Laser device

Abstract

To provide a laser device capable of guiding laser beams emitted from one laser source to different fibers at any power ratio.SOLUTION: The laser device includes: a laser source 2 that emits a laser beam L1; a diffractive optical element 3 for splitting the laser beam with a power ratio based on the incident position of the laser beam; multiple light collection lenses 4A, 4B each collecting multiple laser beams L2A and L2B split by the diffractive optical element; multiple prisms 5A and 5B that change the angle of the laser beams L3A and L3B, which are respectively focused by the multiple light collection lenses, with respect to the end face of the fiber on the input side; and multiple fibers 6A and 6B each allow laser beams L4A and L4B which have passed through the multiple prisms to incident on the end faces of the fiber on the incident side and transit the same therethrough.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a laser device that emits a laser beam. [Background technology]

[0002] 2. Description of the Related Art There is a laser device having a beam switch that splits a laser beam emitted from a laser light source using, for example, an optical element, and enables the laser beam to be guided to different fibers.

[0003] Beam switches, for example, can reduce the number of laser light sources required in production facilities with multiple lines, which is effective in reducing facility installation costs. Also, even if the fiber is damaged for some reason, the presence of a beam switch can reduce the risk of directly affecting the laser light source.

[0004] Patent Document 1 discloses a laser device having a beam switch, which includes a mirror for selectively switching so that a laser beam emitted from one laser light source is guided to one of multiple fibers or multiple fibers, two focusing lenses for focusing the laser beam, and two fibers. Fig. 21 is a schematic diagram showing the configuration of a laser device 101 of the prior art.

[0005] 21 includes a laser light source 102, a motor 103, a beam splitter 104, a total reflection mirror 105, a first fiber 106A, and a second fiber 106B. The laser light source 102 emits a laser beam L101. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] U.S. Patent No. 7,982,935 Summary of the Invention [Problem to be solved by the invention]

[0007] In the laser device 101, the laser beam L101 emitted from the laser light source 102 is split using the beam splitter 104. Therefore, the laser power ratio guided to each fiber 106A, 106B is determined by the optical specifications of the beam splitter 104, and it is difficult to guide the laser beam to multiple fibers at an arbitrary power ratio.

[0008] Therefore, the present disclosure has been made in consideration of such circumstances, and aims to provide a laser device that can guide a laser beam from a laser light source to multiple fibers at any power ratio. [Means for solving the problem]

[0009] In order to achieve the above object, a laser device according to one aspect of the present disclosure includes: a laser light source that emits a laser beam; a diffractive optical element that splits the laser beam at a power ratio based on an incident position of the laser beam; a plurality of condenser lenses that condense the plurality of laser beams branched by the diffractive optical element, respectively; a plurality of prisms for changing the angles of the laser beams respectively focused by the plurality of focusing lenses with respect to the end faces of the fibers on the entrance side; and a plurality of fibers for transmitting the laser beams transmitted through the plurality of prisms by making the laser beams incident on the end faces of the fibers. [Effects of the Invention]

[0010] According to the laser device according to the aspect of the present disclosure, for example, a laser beam emitted from one laser light source can be split into the plurality of laser beams using a diffractive optical element at a power ratio based on the incident position of the laser beam, and the light can be guided to different fibers at any power ratio. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic diagram showing a configuration of a laser device according to a first embodiment of the present disclosure; [Figure 2A] A diagram showing the end face of the fiber when a laser beam is incident on the fiber. [Figure 2B] A diagram showing the cross section of a fiber when a laser beam is incident on it. [Figure 3A] FIG. 10 is a diagram showing a case where a laser beam with 70% of the total power is guided to a first fiber and a laser beam with 30% of the total power is guided to a second fiber according to the first embodiment. [Figure 3B] FIG. 10 is a diagram showing a case where a laser beam with 100% of the total power is guided to a first fiber according to the first embodiment. [Figure 3C] FIG. 10 is a diagram showing a case where a laser beam with 30% of the total power is guided to a first fiber and a laser beam with 70% of the total power is guided to a second fiber according to the first embodiment. [Figure 3D] FIG. 10 is a diagram showing a case where a laser beam with 100% of the total power is guided to a second fiber according to the first embodiment. [Figure 4] FIG. 1 is a diagram showing an example of the configuration of a laser device using a diffractive optical element having three diffraction grating patterns in the case of three fibers according to the first embodiment; [Figure 5] FIG. 1 is a diagram showing an example of the configuration of a laser device in which laser beam branching points are provided in multiple stages when there are three fibers according to the first embodiment; [Figure 6] FIG. 10 is a schematic diagram showing the configuration of a laser device according to a second embodiment of the present disclosure. [Figure 7] A flowchart showing the position control of the diffractive optical element of the laser device of FIG. [Figure 8] FIG. 7 shows the relationship between the actual laser power at the fiber output end of FIG. 6 and the detected value of the power meter. [Figure 9] FIG. 7 is a diagram showing the relationship between the detected value of the power meter in FIG. 6 and the position of the diffractive optical element. [Figure 10] FIG. 7 is a diagram showing the relationship between the position of the diffractive optical element in FIG. 6 and the laser power ratio. [Figure 11]A flowchart showing real-time position control of the diffractive optical element of the laser device of FIG. [Figure 12] A diagram showing the laser beam profile from a laser light source. [Figure 13] FIG. 7 is a diagram showing the time transition of the power ratio between the first fiber and the second fiber when the position of the diffractive optical element in FIG. 6 is not corrected. [Figure 14] FIG. 7 is a diagram showing the time transition of the power ratio between the first fiber and the second fiber when the position of the diffractive optical element in FIG. 6 is corrected. [Figure 15] FIG. 10 is a schematic diagram showing the configuration of a laser device according to a third embodiment of the present disclosure. [Figure 16] A flowchart showing the position control of the fiber of the laser device of FIG. [Figure 17] 16 is a diagram showing the relationship between the amount of change in the profile of FIG. 15 and the amount of deviation of the focal position. [Figure 18] 1 is a diagram showing a profile of a laser beam emitted from the laser device 1. [Figure 19] 19 is a diagram showing an end face on the incident side of the first fiber 6A of FIG. 18. [Figure 20] FIG. 10 is a schematic diagram showing the configuration of a laser device according to a fourth embodiment. [Figure 21] FIG. 1 shows a laser device equipped with a conventional beam switch. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, a laser device according to an embodiment of the present disclosure will be described with reference to FIGS.

[0013] (First embodiment) First, the configuration of a laser device according to a first embodiment of the present disclosure will be described with reference to Fig. 1 to Fig. 5. Fig. 1 is a schematic diagram showing the configuration of a laser device 1 according to a first embodiment of the present disclosure.

[0014] The laser device 1 in Figure 1 is shown in the XZ plane and includes a laser light source 2, a diffractive optical element 3, two focusing lenses 4A and 4B, two prisms 5A and 5B, a first fiber 6A, a second fiber 6B, and a driver 14.

[0015] The laser light source 2 has an internal function of collimating a laser beam and can emit a parallel laser beam L1 from its emission port. For example, a continuous wave fiber laser with a wavelength of 1070 nm and a maximum power of 3 kW can be used as the laser light source 2. In this first embodiment, the laser beam L1 emitted from the laser light source 2 is parallel and has a Gaussian intensity distribution.

[0016] It should be noted that the type of laser light source 2 is not limited to this. For example, the wavelength, power, emission pattern, etc. of the laser may be in the wavelength range of green, blue, UV, etc., or a pulse laser may be used.

[0017] The laser beam L1 emitted from the laser light source 2 travels in the X-axis direction and enters the diffractive optical element 3.

[0018] The diffractive optical element 3 splits the incident laser beam L1 into two laser beams L2A and L2B and emits the two laser beams L2A and L2B. The diffractive optical element 3 is also positioned so as to intersect with the optical axis of the laser beam L1.

[0019] In this first embodiment, the diffractive optical element 3 is formed by processing a fine diffraction grating pattern on the surface of a synthetic quartz plate, and is capable of transmitting at least 50%, preferably 80%, of the incident laser beam L1. Also, Fig. 1 shows a schematic diagram of the diffractive optical element 3. As an example, the diffractive optical element 3 is circular, and the regions of the two types of first and second diffraction grating patterns 3a and 3b are rectangular, and are formed on the surface with no gaps in the Z direction. However, the present disclosure is not limited to this, and three or more types of diffraction grating patterns may be formed.

[0020] 1, for example, the diffractive optical element 3 is disposed so as to intersect perpendicularly with the optical axis of the laser beam L1. However, the present disclosure is not limited to this, and the diffractive optical element 3 may be disposed so as to intersect with the laser beam L1 at any angle. For example, if it is anticipated that a portion of the laser beam L1 incident on the diffractive optical element 3 will not be transmitted and the reflected light from the diffractive optical element 3 will return to the laser light source 2, damaging the laser light source 2, then, for example, the risk of damaging the laser light source 2 can be reduced by tilting the diffractive optical element 3 by about 10° with respect to the optical axis of the laser beam L1.

[0021] Laser beam L2A is a laser beam having an arbitrary first divergence angle that has been transmitted through first diffraction grating pattern 3a of diffractive optical element 3. Laser beam L2B is a laser beam having an arbitrary second divergence angle that is different from the first divergence angle that has been transmitted through second diffraction grating pattern 3b of diffractive optical element 3.

[0022] The first focusing lens 4A receives the parallel laser beam L2A and guides the laser beam L3A, and collects the laser beam L4A at the incident end face of the first fiber 6A via the first prism 5A, causing it to be incident on the first fiber core 6Aa. Similarly, the second focusing lens 4B receives the parallel laser beam L2B and guides the laser beam L3B, and collects the laser beam L4B at the incident end face of the second fiber 6B via the second prism 5B, causing it to be incident on the second fiber core 6Ba.

[0023] In the first embodiment, the first and second condenser lenses 4A and 4B are each spherical convex lenses with a transmittance of at least 50%, preferably 90% or more. Note that the present disclosure is not limited to such condenser lens configurations. That is, the first and second condenser lenses 4A and 4B are not limited to spherical convex lenses, and may be, for example, high-power composite lenses or aspherical lenses, and may be formed from a single lens element or a lens optical system including multiple lens elements.

[0024] When the laser beam L3A having an arbitrary divergence angle from the first focusing lens 4A is incident on the first prism 5A, the first prism 5A guides the laser beam L3A as a laser beam L4A perpendicular to the incident end face of the first fiber 6A. Similarly, when the laser beam L3B having an arbitrary divergence angle from the second focusing lens 4B is incident on the second prism 5B, the second prism 5B guides the laser beam L3B as a laser beam L4B perpendicular to the incident end face of the second fiber 6B.

[0025] In the first embodiment, the first and second prisms 5A and 5B each have a transmittance of at least 50%, preferably 90% or more. While the present disclosure illustrates an example in which such first and second prisms 5A and 5B are used, the present disclosure is not limited to this. For example, a total reflection mirror may be used to cause laser beams L3A and L3B to be incident at an arbitrary angle of incidence, and the laser beams may be guided perpendicularly to the incident end faces of the first and second fibers 6A and 6B as laser beams L4A and L4B.

[0026] FIG. 2A shows the end face of the fiber on the input side when a laser beam L4A is incident on the first fiber 6A, and the laser beam L4A is aligned so that it is centered at the fiber core 6Aa. FIG. 2B shows a cross section of the fiber along its optical axis (however, hatching is omitted to facilitate understanding of light propagation). The first fiber 6A has at least a fiber core 6Aa and a fiber clad 6Ab, which are optical waveguides, and the outer peripheral surface of the fiber clad 6Ab is covered with a light-shielding coating 6Ac. The fiber core 6Aa has a circular shape in a cross section perpendicular to the optical axis direction and is disposed at the axial center of the first fiber 6A. The fiber clad 6Ab is in contact with the outer peripheral surface of the fiber core 6Aa and is disposed coaxially with the fiber core 6Aa, and is ring-shaped in the same cross section.

[0027] The fiber core 6Aa and the fiber clad 6Ab are both made of quartz, for example, but the refractive index nb of the fiber clad 6Ab is set to be lower than the refractive index na of the fiber core 6Aa.

[0028] The second fiber 6B has a similar configuration to the first fiber 6A.

[0029] Using Figure 2B, we will explain why a laser beam is guided perpendicular to the end face on the fiber's input side. The numerical aperture NA of a fiber can be expressed by the following formula (1). The numerical aperture of a fiber indicates the maximum angles of incidence θ1 and θ2 of a laser beam with respect to the fiber at which a laser beam that can propagate through the fiber can be incident. Let the refractive index of the fiber core 6Aa be na, and the refractive index of the fiber cladding 6Ab be nb.

[0030] NA=√(na 2 -nb 2 ) (1) The maximum incident angle θmax that can be propagated can be expressed by the following formula (2) using the numerical aperture NA.

[0031] θmax=sin -1 (NA) (2) Considering a specific example, if the refractive index na of the fiber core 6Aa is 1.465 and the refractive index nb of the fiber cladding 6Ab is 1.451, that is, na = 1.465, nb = 1.451, the maximum incident angle θmax that can be propagated is approximately 11.657°. In this way, θmax is determined by each refractive index.

[0032] When the incident angle θ1 is smaller than the maximum incident angle θmax at which propagation is possible (solid arrow in FIG. 2B), the light is totally reflected within the fiber core 6Aa and propagates.

[0033] On the other hand, if the incident angle θ2 is larger than the maximum incident angle θmax (shown by the dashed arrow in Figure 2B), the laser beam propagates from the fiber core 6Aa into the fiber cladding 6Ab and eventually scatters around the outer periphery of the fiber cladding 6Ab, becoming radiated light. In this case, the radiated light may damage the fiber, which may cause a phenomenon similar to a fiber fuse, resulting in a failure of the fiber. Therefore, it is preferable to guide the laser beam perpendicular to the end face of the fiber on the incident side.

[0034] The drive unit 14 is used to rotate the screw shaft forward and backward, for example, by rotating a motor forward and backward, thereby moving the diffractive optical element 3 engaged with the screw shaft in a direction intersecting the propagation direction of the laser beam (for example, moving it forward and backward in the Z direction in Figure 1), and adjust the incident position of the laser beam L1 on the diffractive optical element 3.

[0035] In the first embodiment, the driver 14 can be configured to be used as a mechanism for moving, in the Z direction, a support holder that has an opening to transmit the laser beam and that fixes and supports the diffractive optical element 3. Therefore, by moving the diffractive optical element 3 in the Z-axis direction using the driver 14, the first and second diffraction grating patterns 3a, 3b are moved, and the incident positions of the laser beam L1 within the first and second diffraction grating patterns 3a, 3b are changed, thereby changing the power ratio based on the incident positions.

[0036] 3A, 3B, 3C, and 3D are schematic diagrams showing the laser device 1 when the diffractive optical element 3 is moved using the driving unit 14. Using these diagrams, a detailed description will be given of the change in the power ratio of the laser beams of the first fiber 6A and the second fiber 6B.

[0037] Figure 3A shows the case where 70% of the laser beam L1 is incident on the area of ​​the first diffraction grating pattern 3a of the diffractive optical element 3 and 30% is incident on the area of ​​the second diffraction grating pattern 3b, and 70% of the power of the laser beam L1 is guided to the first fiber 6A and 30% of the power of the laser beam L1 is guided to the second fiber 6B.

[0038] FIG. 3B shows the case where 100% of the laser beam L1 is incident on the area of ​​the first diffraction grating pattern 3a, and 100% of the power of the laser beam L1 is guided to the first fiber 6A, and the laser beam L1 is not guided to the second fiber 6B.

[0039] FIG. 3C shows a case where 30% of the laser beam L1 is incident on the region of the first diffraction grating pattern 3a of the diffractive optical element 3 and 70% is incident on the region of the second diffraction grating pattern 3b, and 30% of the power of the laser beam L1 is guided to the first fiber 6A and 70% of the power of the laser beam L1 is guided to the second fiber 6B.

[0040] FIG. 3D shows the case where 100% of the laser beam L1 is incident on the region of the second diffraction grating pattern 3b, and the laser beam L1 is not guided to the first fiber 6A, and 100% of the power of the laser beam L1 is guided to the second fiber.

[0041] Specifically, for example, when laser processing two types of workpieces A and B (workpiece A: lap welded SPCC (cold-rolled steel plate) with a thickness of 3 mm, and workpiece B: lap welded SPCC with a thickness of 1 mm) using laser device 1, it is assumed that workpiece A is irradiated with a laser at 2,100 W and workpiece B is irradiated with a laser at 900 W. The power of the first fiber emitting the laser beam on the workpiece A side is set to 2,100 W, and the power of the second fiber emitting the laser beam on the workpiece B side is set to 900 W. In this case, the position of the diffractive optical element 3 is adjusted using the drive unit 14 as shown in FIG. 3A, and the laser light source 2 emits a laser beam L1 with a power of 3,000 W. This allows processing to be performed under the target power ratio conditions appropriate for each workpiece A and B. Furthermore, it is assumed that, for example, during the above laser processing, laser irradiation on the workpiece A side is continued while irradiation on the workpiece B side is stopped. In this case, the drive unit 14 is used to adjust the position of the diffractive optical element 3 as shown in Fig. 3B, and the laser beam L1 is guided only to the first fiber 6A. Also, the power ratio conditions are changed so that the laser light source 2 emits the laser beam L1 with a power of 2,100 W. This makes it possible to change the target power ratio conditions to those suitable for the individual workpieces A and B, which have different processing times, even during laser processing.

[0042] In the first embodiment, the first and second diffraction grating patterns 3a, 3b of the diffractive optical element 3 are rectangular and aligned in the Z-axis direction with no gaps between them, and the position of the diffractive optical element 3 is adjusted in the Z-axis direction using the driver 14. However, the present disclosure is not limited to this. For example, if the first and second diffraction grating patterns 3a, 3b of the diffractive optical element 3 are aligned in the Y-axis direction with no gaps between them, the position of the diffractive optical element 3 can be adjusted in the Y-axis direction, and the movement direction can be changed in any direction to match any shape or arrangement of the diffraction grating patterns.

[0043] In addition, in this first embodiment, when there are two fibers, the laser beam L1 is split into laser beam L2A and laser beam L2B at an arbitrary power ratio and guided to each fiber 6A, 6B, but this can also be applied to when there are three or more fibers.

[0044] Fig. 4 shows a configuration example in which there are three fibers. The laser device 1 is shown on the XZ plane and includes a laser light source 2, a diffractive optical element 3, three focusing lenses 4A, 4B, and 4C, three prisms 5A, 5B, and 5C, a first fiber 6A, a second fiber 6B, a third fiber 6C, and a driver 14. Detailed explanations of parts having the same configuration as the first embodiment shown in Fig. 1 will be omitted. The third fiber 6C has the same configuration as the first fiber 6A.

[0045] The diffractive optical element 3 has a circular shape, and the regions of the three types of diffraction grating patterns 3a, 3b, and 3c are each rectangular and formed in a horizontal T shape with no gaps in the Z-axis and Y-axis directions.

[0046] Laser beam L2A is a laser beam with an arbitrary divergence angle that has been transmitted through diffraction grating pattern 3a of diffractive optical element 3. Laser beam L2B is a laser beam with an arbitrary divergence angle that has been transmitted through diffraction grating pattern 3b of diffractive optical element 3. Laser beam L2C is a laser beam with an arbitrary divergence angle that has been transmitted through diffraction grating pattern 3c of diffractive optical element 3. The three divergence angles are different from each other.

[0047] The driving unit 14 can be configured to have an opening that allows the laser beam L1 to pass through and to be used as a support holder for fixing and supporting the diffractive optical element 3. The driving unit 14 can also move the diffractive optical element 3 in the Z-axis direction and the Y-axis direction. Thus, the driving unit 14 is used to move the diffractive optical element 3 back and forth in the Z-axis direction and the Y-axis direction in FIG. 4, thereby adjusting the incident position of the laser beam L1 on the diffractive optical element 3.

[0048] Regarding the change in the power ratio of the laser beam L1 among the first fiber 6A, the second fiber 6B, and the third fiber 6C, for example, when the laser beam L1 is incident on the region of the diffraction grating pattern 3a of the diffractive optical element 3 at 50%, on the region of the diffraction grating pattern 3b at 30%, and on the region of the diffraction grating pattern 3c at 20%, 50% of the total laser beam power is guided to the first fiber 6A, 30% of the total laser beam power is guided to the second fiber 6B, and 20% of the total laser beam power is guided to the third fiber 6C.

[0049] 5 shows another example of a configuration in which light is guided to three fibers. The laser device 1 is shown in the XZ plane and includes a laser light source 2, two diffractive optical elements 3 and 7, three condenser lenses 4A, 4E, and 4D, four prisms 5A, 5B, 5D, and 5E, three first fibers 6A, a fourth fiber 6D, and a fifth fiber 6E, and two drivers 14 and 15. Detailed descriptions of components similar to those of the first embodiment shown in FIG. 1 will be omitted.

[0050] This configuration example has two diffractive optical elements 3 and 7. The first diffractive optical element 3 splits the laser beam L1 from the laser light source 2 into two beams, and one of the split laser beams, L2A, is finally guided to the first fiber 6A. The other split laser beam, L2B, passes through the prism 5B and is guided to the second diffractive optical element 7 as the laser beam L4F. The diffractive optical element 7 then splits the laser beam L4F into two beams, and one of the split laser beams, L2D, is guided to the fourth fiber 6D, and the other of the split laser beams, L2E, is guided to the fifth fiber 6E. In this way, the splitting optical system using the diffractive optical elements 3 and 7 is provided in multiple stages. However, this is not limited to this, and a multi-stage system with three or more stages may also be used. The area shape of the diffraction grating pattern of the diffractive optical element used may also be arbitrary, and the number of diffraction grating patterns may be three or more.

[0051] Laser beam L2D is a laser beam with an arbitrary divergence angle that has passed through diffraction grating pattern 7a of diffractive optical element 7. Laser beam L2E is a laser beam with an arbitrary divergence angle that has passed through diffraction grating pattern 7b of diffractive optical element 7. The two divergence angles are different from each other.

[0052] The driving unit 15 can be configured to have an opening that allows the laser beam L4F to pass through and to be used as a support holder for fixing and supporting the diffractive optical element 7. The driving unit 15 is also used to move the diffractive optical element 7 back and forth in the Z-axis direction to adjust the incident position of the laser beam L4F on the diffractive optical element 7.

[0053] Regarding the change in the power ratio of the laser beam L1 among the first fiber 6A, the fourth fiber 6D, and the fifth fiber 6E, for example, if the laser beam L1 is incident 50% on the region of the diffraction grating pattern 3a of the diffractive optical element 3 and 50% on the region of the diffraction grating pattern 3b, and the laser beam L4F is incident 60% on the region of the diffraction grating pattern 7a of the diffractive optical element 7 and 40% on the region of the diffraction grating pattern 7b, then 50% of the total laser beam power is guided to the first fiber 6A, 30% of the total laser beam power is guided to the fourth fiber 6D, and 20% of the total laser beam power is guided to the fifth fiber 6E.

[0054] As described above, in the first embodiment, the laser device 1 can branch the laser beam L1 from the laser light source 2 into multiple laser beams using one or multiple diffractive optical elements 3 or 3, 7, so that the laser beams can be branched to be guided to multiple fibers 6A, 6B or 6A, 6B, 6C or 6A, 6D, 6E. Furthermore, by changing the incident position of the laser beam L1 or L1, L4F with respect to the diffractive optical element 3 or 3, 7 on which multiple diffraction grating patterns 3a, 3b or 3a, 3b, 3c or 3a, 3b, 7a, 7b are formed, the laser beam L1 or L1, L4F can be guided at any power ratio to multiple fibers 6A, 6B or 6A, 6B, 6C or 6A, 6D, 6E.

[0055] (Second embodiment) Below, we will explain a laser device according to another embodiment of the present disclosure, which can correct fluctuations in the state of a laser beam using the power of the reflected light of the laser beam from a prism as an example of a characteristic quantity that indicates fluctuations in the state of the laser beam during laser irradiation.

[0056] The configuration of a laser device according to a second embodiment of the present disclosure will be described with reference to Fig. 6 to Fig. 14. Fig. 6 is a schematic diagram showing the configuration of a laser device 1 according to a second embodiment of the present disclosure. In Fig. 6, the same components as those in the laser device 1 according to the first embodiment shown in Fig. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0057] The laser device 1 in Figure 6 is shown in the XZ plane and includes a laser light source 2, a diffractive optical element 3, two focusing lenses 4A and 4B, two prisms 5A and 5B, a first fiber 6A, a second fiber 6B, power meters 8A and 8B as an example of a detection unit, a calculation unit 9, a control unit 10, and a drive unit 14.

[0058] Power meter 8A is used to detect the relative power of laser beam L3A by receiving reflected light 11A from prism 5A and measuring its power, and the detected power detection data is sent to calculation unit 9. Power meter 8B is used to detect the relative power of laser beam L3B by receiving reflected light 11B from prism 5B and measuring its power, and the detected power detection data is sent to calculation unit 9. In the second embodiment, for example, power meters 8A and 8B can be configured with visible light photodiodes that are sensitive to the wavelength band of the laser beam. However, without being limited to this, a thermopile-type power sensor or the like may also be used.

[0059] The calculation unit 9 calculates the position of the diffractive optical element 3 based on the data detected by the power meters 8A and 8B. Data on the relationship between the detection value of the power meter 8A and the actual laser power at the output end of the first fiber 6A, and the relationship between the detection value of the power meter 8B and the actual laser power at the output end of the second fiber 6B are acquired in advance. Using these data, the power meters 8A and 8B can monitor the relative actual laser powers at the output ends of the first fiber 6A and the second fiber 6B. Furthermore, by calculating the position of the diffractive optical element 3 so as to correct fluctuations in the power ratio between the power meters 8A and 8B, it is possible to correct fluctuations in the ratio of the actual laser powers at the output ends of the first fiber 6A and the second fiber 6B. In the second embodiment, the calculation unit 9 is, for example, a computer device. A general-purpose computer device can be used as this computer device, and it may include an input device, a storage device, an interface, etc.

[0060] The control unit 10 can control the power ratio of the power meters 8A, 8B to match the set power ratio conditions based on the position of the diffractive optical element 3 calculated by the calculation unit 9, and can also control the power meters 8A, 8B to correct fluctuations in the power ratio during laser beam irradiation. In the second embodiment, the control unit 10 uses the drive unit 14 to move the position of the diffractive optical element 3 based on the position data of the diffractive optical element 3 received from the calculation unit 9, thereby controlling the power ratio.

[0061] The control process of the actual laser power ratio at the output ends of the first fiber 6A and the second fiber 6B by the calculation unit 9 and the control unit 10 of the laser device 1 according to the second embodiment of the present disclosure will be described below with reference to Figures 6 to 14.

[0062] FIG. 7 is a flowchart showing a control process of the power ratio between the first fiber 6A and the second fiber 6B by the calculation unit 9 and the control unit 10 of the laser device 1 according to the second embodiment.

[0063] First, in step S1, the laser light source 2 emits a laser beam L1 under the control of the control unit 10. At that time, data on the relationship between the actual laser power at the output end of the first fiber 6A and the value detected by the power meter 8A, and data on the relationship between the actual laser power at the output end of the second fiber 6B and the value detected by the power meter 8B are acquired by the calculation unit 9. The actual laser power at the output end of each fiber 6A, 6B may be measured, for example, by using a thermopile-type power sensor at the fiber output end. Figure 8 is an example graph showing the relationship between the actual laser power at the output end of the first fiber 6A and the value detected by the power meter 8A, and such data is acquired in step S1.

[0064] Next, in step S2, the calculation unit 9 acquires data relating to the relationship between the detected values ​​of the power meters 8A and 8B and the position of the diffractive optical element 3. FIG. 9 is an example graph showing the relationship between the positions of the power meter 8A and the diffractive optical element 3. Moving the diffractive optical element 3 in the positive direction of the Z axis reduces the incidence rate of the laser beam L1 on the region of the diffraction grating pattern 3a formed on the diffractive optical element 3. This reduces the power of the laser beam L3A after passing through the diffraction grating pattern 3a, and accordingly reduces the power of the reflected light 11A from the prism 5A. Therefore, moving the diffractive optical element 3 in the positive direction of the Z axis reduces the detected value of the power meter 8A. On the other hand, moving the diffractive optical element 3 in the negative direction of the Z axis increases the incidence rate of the laser beam L1 on the region of the diffraction grating pattern 3a formed on the diffractive optical element 3. This increases the power of the laser beam L3A after passing through the diffraction grating pattern 3a, and accordingly increases the power of the reflected light 11A from the prism 5A. Therefore, when the diffractive optical element 3 is moved in the negative direction of the Z axis, the detected value of the power meter 8A increases. In step S2, the calculation unit 9 acquires such data.

[0065] Next, in step S3, the calculation unit 9 derives the relationship between the position of the diffractive optical element 3 and the laser power ratio between the first fiber 6A and the second fiber 6B. FIG. 10 is a graph showing an example of the relationship between the position of the diffractive optical element 3 and the power ratio between the first fiber 6A and the second fiber 6B. The relationship data between the actual laser power at the output end of the first fiber 6A and the value detected by the power meter 8A, and the relationship data between the actual laser power at the output end of the second fiber 6B and the value detected by the power meter 8B, obtained in step S1, are used. Furthermore, the relationship data between the positions of the power meters 8A and 8B and the diffractive optical element 3, obtained in step S2, is used. Using these data, the calculation unit 9 derives the relationship between the position of the diffractive optical element 3 and the power ratio between the first fiber 6A and the second fiber 6B.

[0066] Next, in step S4, the calculation unit 9 calculates the position of the diffractive optical element 3 using the relationship between the position of the diffractive optical element 3 derived in step S3 and the power ratio between the first fiber 6A and the second fiber 6B so as to match the set power ratio condition. This position data is sent from the calculation unit 9 to the control unit 10, and the diffractive optical element 3 moves to the calculated position.

[0067] Next, in step S5, irradiation of the laser light source 2 is started, whereby the laser beams L4A and L4B are guided to the fibers 6A and 6B, respectively, and the laser beams are emitted from the fibers 6A and 6B.

[0068] Next, in step S6, the calculation unit 9 calculates the position of the diffractive optical element 3 in accordance with the set power ratio conditions while the laser beam L1 is being irradiated from the laser light source 2. This position data is sent from the calculation unit 9 to the control unit 10, and under the control of the control unit 10, the drive unit 14 moves the diffractive optical element 3 to the calculated position.

[0069] The reason for performing the same movement operation as in step S4 during laser beam irradiation in step S6 is to accommodate a change in the set power ratio conditions in step S4. For example, suppose that during laser processing, laser irradiation on workpiece A continues while irradiation on workpiece B is stopped. In this case, the drive unit 14 is used to move and adjust the position of the diffractive optical element 3 as shown in FIG. 3B, and the laser beam L1 is guided only to the first fiber 6A. In addition, the power ratio conditions are changed so that the laser light source 2 emits a laser beam L1 with a power of 2,100 W. This allows the power ratio conditions to be changed during laser processing to suit the individual workpieces A and B, which have different processing times.

[0070] Next, in step S7, the control unit 10 determines whether or not the laser irradiation is complete, and the control unit 10 repeatedly executes the process of step S6 until the laser irradiation is complete.

[0071] As described above, in the second embodiment, the laser device 1 uses the diffractive optical element 3 to split the laser beam L1 from the laser light source into multiple laser beams L2A and L2B, thereby enabling the splitting to be guided to multiple fibers 6A and 6B. Furthermore, the power ratio between each fiber 6A and 6B is determined by detecting reflected light 11A and 11B from the prisms 5A and 5B in advance, and using the power of the detected reflected light 11A and 11B, the calculation unit 9 derives the relationship between the position of the diffractive optical element 3 and the power ratio of each fiber 6A and 6B. Based on this data, the position of the diffractive optical element 3 is moved to achieve a set power ratio condition, thereby changing the incident position of the laser beam L1 relative to the diffractive optical element 3 on which multiple diffraction grating patterns 3a and 3b are formed. This allows the laser beam L1 to be guided to multiple fibers 6A and 6B at any desired power ratio.

[0072] FIG. 11 is a flowchart showing a real-time correction control process of the power ratio between the fibers 6A and 6B by the control unit 10 of the laser device 1 according to the second embodiment.

[0073] Figure 12 shows the beam profile of the laser beam L1 from the laser light source 2. P1 is a beam profile with a normal distribution, which is the expected beam profile. However, during continuous oscillation of the laser beam L1, the beam profile may become unstable and fluctuate. For example, it is possible that the beam profile may become biased as shown in P2 or have a concave portion as shown in P3 during laser irradiation. This changes the incidence rate of the laser beam L1 on the diffraction grating patterns 3a and 3b formed on the diffractive optical element 3, even if the position of the diffractive optical element 3 remains unchanged. As a result, the power of the branched laser beams L2A and L2B transmitted through the diffractive optical element 3 changes due to the profile fluctuation, which may result in a discrepancy between the laser power output from each fiber 6A and 6B and the set power ratio conditions.

[0074] Therefore, in the second embodiment, even if fluctuations occur in the beam profile, the power ratio between the fibers 6A and 6B can be corrected in real time by executing the following steps S11 to S15.

[0075] First, the processes in steps S8, S9, and S10 are the same as steps S1 to S5 in the flowchart of FIG. 7, and therefore a description thereof will be omitted.

[0076] Next, in step S11, the power meters 8A and 8B detect the reflected lights 11A and 11B from the prisms 5A and 5B, respectively, during irradiation of the laser beam L1 from the laser light source 2. The detected values ​​are sent to the calculation unit 9.

[0077] Next, in step S12, the calculation unit 9 determines in real time during laser beam irradiation whether the detected value is different from the set power ratio condition between the fibers 6A and 6B. Fig. 13 shows an example of the time transition of the power ratio between the first fiber 6A and the second fiber 6B when there is no real-time correction of the position of the diffractive optical element 3. For example, this shows a case where the set power ratio condition is set to 50% for the first fiber 6A and 50% for the second fiber 6B, and due to fluctuations in the beam profile as shown in Fig. 12, the actual power ratio differs from the set power ratio condition.

[0078] Next, in step S13, when the deviation is equal to or greater than a predetermined value taking into account an error, the calculation unit 9 determines the position of the diffractive optical element 3, as an example of an optical component, so as to correct the deviation (i.e., the amount of deviation) in the power ratio between the fibers 6A and 6B. For example, suppose that, for the set power ratio condition in step S12, the calculation unit 9 derives the actual power ratios of 46% for the first fiber 6A and 54% for the second fiber 6B using the detected values ​​of the power meters 8A and 8B, respectively. At this time, the calculation unit 9 calculates the position of the diffractive optical element 3 so that the actual power ratio between the first fiber 6A and the second fiber 6B satisfies the set power ratio condition.

[0079] Next, in step S14, data on the position of the diffractive optical element 3 calculated by the calculation unit 9 is sent to the control unit 10, and the driver 14 is driven under the control of the control unit 10 to move the diffractive optical element 3 to the calculated position. As a result, it is possible to correct in real time any deviation of the actual power ratio from the set power ratio condition. For example, using the data on the position of the diffractive optical element 3 calculated in step S13, the driver 14 is driven under the control of the control unit 10 to move the diffractive optical element 3 to the calculated position in the negative direction of the Z axis. FIG. 14 shows an example of the time transition of the power ratio of the first fiber 6A and the second fiber 6B when real-time correction of the position of the diffractive optical element 3 is performed. This shows that even when fluctuations in the beam profile occur, it is possible to correct in real time any deviation of the actual power ratio from the set power ratio condition.

[0080] Next, in step S15, it is determined whether or not the laser irradiation is complete, and the processes from steps S11 to S14 are repeatedly executed until the laser irradiation is complete.

[0081] In this way, in the second embodiment, the laser device 1 can use the power meters 8A and 8B during laser beam irradiation to calculate the position of the diffractive optical element 3 in real time from the deviation in the power ratio between the fibers 6A and 6B, thereby guiding light to the multiple fibers 6A and 6B while correcting the deviation in the power ratio.

[0082] (Third embodiment) In the laser device 1, while the laser light source 2 is irradiating the fibers 6A and 6B, a shift in the focal position of the laser beams L4A and L4B may occur due to the thermal lens effect of the optical system, such as the condenser lenses 4A and 4B. This may cause the laser beams L4A and L4B to not fit completely into the fiber core at the end face on the incident side, leading to fiber damage. Below, we will describe a laser device according to another embodiment of the present disclosure, which can correct the shift in the focal position of the laser beams L4A and L4B using the size of the profile of the reflected light 11A and 11B of the laser beams L3A and L3B from the prisms 5A and 5B as a characteristic quantity indicating fluctuations in the state of the laser beam.

[0083] The configuration of a laser device according to a third embodiment of the present disclosure will be described with reference to Fig. 15 to Fig. 17. Fig. 15 is a schematic diagram showing the configuration of a laser device 1 according to a third embodiment of the present disclosure. In Fig. 15, components similar to those of the laser device 1 according to the first embodiment shown in Fig. 1 and the laser device 1 according to the second embodiment shown in Fig. 6 are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0084] The laser device 1 in Figure 15 is shown in the XZ plane and includes a laser light source 2, a diffractive optical element 3, two focusing lenses 4A and 4B, two prisms 5A and 5B, a first fiber 6A, a second fiber 6B, a calculation unit 9, a control unit 10, two profilers 12A and 12B, and three driving units 14, 16, and 17.

[0085] The driving units 16 and 17 are devices similar to the driving unit 14, and are used to rotate the screw shaft forward and backward by, for example, rotating a motor forward and backward, thereby moving the first fiber 6A and the second fiber 6B engaged with the screw shaft forward and backward in the X-axis direction in Figure 15, thereby aligning the incident side end face of the first fiber 6A with the focal point of the laser beam L4A and aligning the incident side end face of the second fiber 6B with the focal point of the laser beam L4B.

[0086] Profiler 12A receives reflected light 11A from prism 5A and detects a profile, and the detected profile detection data is transmitted to calculation unit 9. Profiler 12B receives reflected light 11B from prism 5B and detects a profile, and the detected profile detection data is transmitted to calculation unit 9. In the third embodiment, for example, profilers 12A and 12B can be configured as CMOS camera type profilers capable of measuring the wavelength bands of laser beams L3A and L3B. However, without being limited to this, CCD camera type profilers or the like may also be used.

[0087] The calculation unit 9 is used to calculate the respective positions of the first fiber 6A and the second fiber 6B, based on the profiles detected by the profilers 12A and 12B, such that the focal point of the laser beam L4A coincides with the incident end face of the first fiber 6A during laser beam irradiation, and such that the focal point of the laser beam L4B coincides with the incident end face of the second fiber 6B. Specifically, for example, a database is created in the calculation unit 9, which is a relationship table calculated in advance by a simulation such as that shown in FIG. 17 between the diameters of the profiles detected by the profilers 12A and 12B and the deviations of the laser beam focal positions. The calculation unit 9 calculates the profile change amount ΔD based on the data detected by the profilers 12A and 12B, and the calculation unit 9 can obtain the fiber position correction amount Zf as an output value based on the created database and the profile change amount ΔD.

[0088] The control unit 10 can drive and control the drivers 16 and 17 so as to correct the position of the first fiber 6A and the position of the second fiber 6B, respectively, based on the fiber position correction amount Zf calculated by the calculation unit 9. In the third embodiment, the control unit 10 controls the positions of the first fiber 6A and the second fiber 6B by using the drivers 16 and 17, based on the positions received from the calculation unit 9.

[0089] Although the present disclosure shows an example in which the positions of the first fiber 6A and the second fiber 6B are adjusted, the present disclosure is not limited to this. For example, a configuration may be adopted in which the positions of the condenser lenses 4A and 4B are adjusted so that the focal point of the laser beam L4A coincides with the incident end face of the first fiber 6A and the focal point of the laser beam L4B coincides with the incident end face of the second fiber 6B.

[0090] A control process for correcting the positions of the first fiber 6A and the second fiber 6B by the control unit 10 and the calculation unit 9 of the laser device 1 according to the third embodiment of the present disclosure will be described below with reference to FIGS.

[0091] FIG. 16 is a flowchart showing a control process for correcting the positions of the first fiber 6A and the second fiber 6B by the control unit 10 and the calculation unit 9 of the laser device 1 according to the third embodiment.

[0092] First, in step S16, a relationship table between the diameter of the profiles detected by the profilers 12A and 12B and the deviation amount of the laser beam focal position, which is calculated in advance by a simulation such as that shown in Figure 17, is created and stored as a database in the calculation unit 9.

[0093] After the start of irradiation in step S17, in step S18, profilers 12A and 12B detect reflected light 11A and 11B from prisms 5A and 5B during irradiation of laser beam L1 from laser light source 2, and the detected data is sent to calculation unit 9.

[0094] Next, in step S19, the calculation unit 9 determines the deviation of the focal position in real time during the laser beam irradiation. For example, suppose that due to the thermal lens effect of the optical system of the laser device 1, the profiler 12A detects a profile diameter D1 that is larger than the profile diameter D0 when no deviation of the focal position occurs. In other words, by using the diameters D1 and D0 as input values ​​before and after the occurrence of the thermal lens effect, the calculation unit 9 derives and determines that a profile change amount ΔD has occurred, where ΔD=D1-D0 Next, in step S20, the calculation unit 9 calculates the amount of deviation of the focal positions of the laser beams L4A and L4B with respect to the fibers 6A and 6B based on the profile change amount ΔD derived by the calculation unit 9. In other words, the calculation unit 9 reads out a relationship table ( FIG. 17 ) calculated in advance between the diameters of the profiles detected by the profilers 12A and 12B and the amount of deviation of the laser beam focal positions, and by using the read-out relationship table and the profile change amount ΔD during laser irradiation, the calculation unit 9 can obtain the fiber position correction amount Zf as an output value. Data on the calculated fiber position correction amount Zf is sent from the calculation unit 9 to the control unit 10.

[0095] Next, in step S21, the control unit 10 transmits the positions of the fibers 6A and 6B to the driving units 16 and 17 based on the fiber position correction amount Zf received from the calculation unit 9. For example, as shown in FIG. 15, the driving unit 16 operates to move the first fiber 6A, as an example of an optical component, in the negative direction of the X-axis, thereby moving the first fiber 6A from the position indicated by the dashed line to the position indicated by the solid line (in other words, the position of the transmitted first fiber 6A), and the focal point of the laser beam L4A is aligned with the end face of the incident side of the first fiber 6A during laser beam irradiation. In addition, the driving unit 17 operates to move the second fiber 6B, as an example of an optical component, in the positive direction of the X-axis, thereby moving the second fiber 6B from the position indicated by the dashed line to the position indicated by the solid line (in other words, the position of the transmitted second fiber 6B), and the focal point of the laser beam L4B is aligned with the end face of the incident side of the second fiber 6B during laser beam irradiation.

[0096] Next, in step S22, the control unit 10 determines whether or not the laser irradiation is complete, and the control unit 10 repeats the processes from steps S18 to S21 until the laser irradiation is complete.

[0097] In this way, in the third embodiment, the laser device 1 uses the profilers 12A, 12B during laser beam irradiation to calculate in real time in the calculation unit 9 the amount of correction for the positions of the fibers 6A, 6B from the amount of deviation of the focal position relative to the fibers 6A, 6B, thereby being able to guide the light to multiple fibers 6A, 6B while correcting the deviation of the focal position.

[0098] When the amount of focal position shift is calculated by the calculation unit 9, the amount of focal position shift of the laser beam may be corrected by moving the position of the condenser lenses 4A, 4B, as another example of an optical component, instead of the position of the end face on the fiber entrance side. In this case, as a driving unit for moving the positions of the optical components, driving units similar to the driving units 16, 17 for moving the position of the end face on the fiber entrance side may be provided for moving the positions of the condenser lenses 4A, 4B.

[0099] (Fourth embodiment) In the laser device 1, a laser beam L3A having an arbitrary branching angle passes through the diffractive optical element 3 and enters the prism 5A, where it is guided as a laser beam L4A perpendicular to the end face of the incident side of the first fiber 6A. Furthermore, a laser beam L3B having an arbitrary branching angle enters the prism 5B, where it is guided as a laser beam L4B perpendicular to the end face of the incident side of the second fiber 6B. At this time, the profile shapes of the laser beams L3A and L3B may change as they pass through the prisms 5A and 5B. For example, as shown in FIG. 18, the beam shape emitted from the laser light source 2 is circular (i.e., laser beam profile shape L1P), and after passing through the diffractive optical element 3, the beam shape becomes circular as the laser beam L2A (i.e., laser beam profile shape L2AP). The laser beam L3A then passes through the condenser lens 4A and then through the prism 5A, whereby the laser beam L4A has an elliptical beam shape (i.e., laser beam profile shape L4AP). In this case, as shown in FIG. 19, it is necessary to prepare a first fiber 6A such that the elliptical laser beam profile shape L4AP fits within the fiber core 6Aa. This requires that the diameter of the fiber core 6Aa be larger than in the case of a circular laser beam profile shape (shown by the dashed line), which affects the laser beam quality at the fiber output end. Below, we will describe a laser device according to another embodiment of the present disclosure, in which the laser beam shape of the laser device is adjusted to match the fiber core shape.

[0100] The configuration of a laser device according to a fourth embodiment of the present disclosure will be described with reference to Fig. 20. Fig. 20 is a schematic diagram showing the configuration of a laser device 1 according to the fourth embodiment of the present disclosure. In Fig. 20, the same components as those in the laser device 1 according to the first embodiment shown in Fig. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0101] The laser device 1 in Figure 20 is shown in the XZ plane and includes a laser light source 2, a diffractive optical element 3, two focusing lenses 4A and 4B, two prisms 5A and 5B, a first fiber 6A, a second fiber 6B, and a cylindrical lens 13.

[0102] The cylindrical lens 13 is disposed between the laser light source 2 and the diffractive optical element 3. When the laser beam L1 emitted from the laser light source 2 passes through the cylindrical lens 13, the laser beam L1 after passing through the cylindrical lens 13 becomes an ellipse with a laser beam profile shape L1P. The elliptical laser beam L1 then passes through the diffractive optical element 3, and the laser beam L2A becomes an ellipse as shown by the laser beam profile shape L2AP, and the laser beam L2B becomes an ellipse as shown by the laser beam profile shape L2BP. The laser beam L2A passes through the condenser lens 4A and the prism 5A, and becomes a circular laser beam L4A as shown by the laser beam profile shape L4AP. The laser beam L2B passes through the condenser lens 4B and the prism 5B, and becomes a circular laser beam L4B as shown by the laser beam profile shape L4BP.

[0103] In this way, in the fourth embodiment, the laser beam shape of the laser device can be guided in a configuration that matches the shape of the fiber core.

[0104] It should be noted that any of the various embodiments or modifications described above can be appropriately combined to achieve the effects of each. In addition, combinations of embodiments, combinations of examples, or combinations of embodiments and examples are possible, and combinations of features from different embodiments or examples are also possible.

[0105] (Addendum) The above description of the embodiments discloses the following techniques.

[0106] (Technology 1) A laser light source that emits a laser beam; a diffractive optical element that splits the laser beam at a power ratio based on an incident position of the laser beam; a plurality of condenser lenses that condense the plurality of laser beams branched by the diffractive optical element, respectively; a plurality of prisms for changing the angles of the laser beams respectively focused by the plurality of focusing lenses with respect to the end faces of the fibers on the entrance side; a plurality of fibers for transmitting the laser beams transmitted through the plurality of prisms by making the laser beams incident on the end faces of the fibers.

[0107] (Technology 2) The diffractive optical element has a plurality of diffraction grating patterns different from one another on its surface, The laser device according to technique 1 further comprises a driving unit that moves the diffractive optical element in a direction intersecting the propagation direction of the laser beam to change the incident position of the laser beam with respect to the plurality of diffraction grating patterns.

[0108] (Technology 3) A detection unit that detects a characteristic quantity that indicates a change in the state of the laser beam during laser irradiation; a calculation unit that calculates at least one of a power deviation amount and a focus deviation amount of the laser beam based on the characteristic amount detected by the detection unit; The laser device according to Art. 2, further comprising: a control unit that controls movement of a position of an optical component of the laser device so as to correct at least one of the power deviation amount and the focus deviation amount of the laser beam calculated by the calculation unit.

[0109] (Technology 4) A laser device according to Technology 3, wherein when the power deviation is calculated by the calculation unit, the power deviation of the laser beam is corrected by moving the position of the diffractive optical element as the optical component.

[0110] (Technology 5) A laser device according to Technology 3, wherein when the calculation unit calculates the amount of focus deviation, the amount of focus deviation of the laser beam is corrected by moving at least one of the position of the end face on the fiber entrance side and the position of the focusing lens as the optical component.

[0111] (Technology 6) The laser device according to any one of Technologies 1 to 5, further comprising an optical system for changing the profile shape of the laser beam incident on the diffractive optical element.

[0112] With each of these configurations, for example, a laser beam emitted from one laser light source can be split into multiple laser beams using a diffractive optical element at a power ratio based on the incident position of the laser beam, and the light can be guided to different fibers at any power ratio. [Industrial Applicability]

[0113] The present disclosure is applicable to, for example, a laser device that enables laser beams emitted from one laser light source to be branched into different fibers at an arbitrary power ratio and guided therethrough. [Explanation of symbols]

[0114] 1: Laser device 2: Laser light source 3: Diffractive optical element 3a, 3b: Diffraction grating pattern 4A, 4B, 4C: Condenser lenses 5A, 5B, 5C: Prism 6A: First fiber 6B: Second fiber 6C: Third fiber 6Aa, 6Ba, 6Ca: fiber core 6Ab, 6Bb, 6Cb: Fiber cladding 6Ac, 6Bc, 6Cc: Coating L1, L2A, L3A, L4A, L2B, L3B, L4B, L2C, L3C, L4C: Laser beam 7: Diffractive optical element 8A, 8B: Power meter 9: Arithmetic section 10: Control unit 11A, 11B: Reflected light 12A, 12B: Profiler 13: Cylindrical lens 14, 15, 16, 17: Drive unit L1P, L2AP, L4AP, L2BP, L4BP: Laser beam profile shapes 101: Laser device 102: Laser light source 103: Motor 104: Beam splitter 105: Total reflection mirror 106A: First fiber 106B: Second fiber L101: Laser beam

Claims

1. a laser light source that emits a laser beam; a diffractive optical element that splits the laser beam at a power ratio based on an incident position of the laser beam; a plurality of condenser lenses that condense the plurality of laser beams branched by the diffractive optical element, respectively; a plurality of prisms for changing the angles of the laser beams respectively focused by the plurality of focusing lenses with respect to the end faces of the fibers on the entrance side; a plurality of fibers for transmitting the laser beams transmitted through the plurality of prisms by making the laser beams incident on the end faces of the fibers.

2. the diffractive optical element has a plurality of diffraction grating patterns different from one another on a surface thereof; 2. The laser device according to claim 1, further comprising a drive unit that moves the diffractive optical element in a direction intersecting a propagation direction of the laser beam to change an incident position of the laser beam with respect to the plurality of diffraction grating patterns.

3. a detection unit that detects a characteristic quantity that indicates a change in the state of the laser beam during laser irradiation; a calculation unit that calculates at least one of a power ratio deviation amount and a focal position deviation amount of the laser beam based on the characteristic amount detected by the detection unit; 3. The laser device according to claim 2, further comprising: a control unit that controls movement of a position of an optical component of the laser device so as to correct at least one of the power ratio deviation amount and the focal position deviation amount of the laser beam calculated by the calculation unit.

4. 4. The laser device according to claim 3, wherein when the power ratio deviation amount is calculated by the calculation unit, the power ratio deviation amount of the laser beam is corrected by moving the position of the diffractive optical element as the optical component.

5. 4. The laser device according to claim 3, wherein when the calculation unit calculates the amount of focal position shift, the amount of focal position shift of the laser beam is corrected by moving at least one of the position of the end face on the fiber incident side and the position of the focusing lens as the optical component.

6. The laser device according to claim 1 , further comprising an optical system that changes a profile shape of the laser beam incident on the diffractive optical element.

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