Laser device and laser processing device

Abstract

The laser device (110) includes a laser light source (1) having a light emitting point (1a) that emits a laser beam (r), an optical element (E), a transmission type diffraction grating (5), and an output coupler (6). The transmission type diffraction grating (5) is disposed at an overlapping position (S) where the laser beams (r) emitted from each of the multiple laser light sources (1) overlap, and is disposed parallel to a direction perpendicular to the plane. A first gap (7) is formed between two adjacent laser light sources (1) among the multiple laser light sources (1), and is located on the optical path of the reflected first-order diffracted light (r2) emitted from the transmission type diffraction grating (5). A first angle (θ1) formed by a virtual line (C1) connecting the overlap position (S) and a light-emitting point (1b) located on one side of the first gap (7) and closest to the first gap (7), and a virtual line (C2) connecting the overlap position (S) and a light-emitting point (1c) located on the other side of the first gap (7) and closest to the first gap (7), is 0.15 degrees or more.

Description

[Technical field]

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

[0002] Conventionally, there is known a laser device including a plurality of laser light sources, an optical element, a transmission type diffraction grating, and an output coupler. The laser light source emits a laser beam. The optical element collimates the laser beam emitted from the laser light source. The transmission type diffraction grating coaxially superimposes a portion of the laser beam emitted from the optical element, and emits the coaxially superimposed laser beam as transmitted first-order diffracted light. The output coupler reflects a portion of the transmitted first-order diffracted light emitted from the transmission type diffraction grating toward the laser light source, and emits the remaining portion of the transmitted first-order diffracted light emitted from the transmission type diffraction grating.

[0003] When a laser beam is incident on a transmission grating, not only the transmitted first-order diffracted light but also the reflected first-order diffracted light is emitted from the transmission grating. The reflected first-order diffracted light is a light in which multiple laser beams are superimposed on the same axis, just like the transmitted first-order diffracted light, so the light intensity of the reflected first-order diffracted light is relatively high. The reflected first-order diffracted light is emitted from the transmission grating toward the laser light source. If the reflected first-order diffracted light is irradiated onto the laser light source, there is a problem that it may cause damage to the laser light source. In particular, the higher the output of the laser beam emitted from the laser light source, the higher the output of the reflected first-order diffracted light will be, which may cause damage to the laser light source, so there is a demand for technology to suppress the irradiation of the laser light source by the reflected first-order diffracted light.

[0004] For example, Patent Document 1 discloses a technique in which a plurality of laser light sources and a transmission type diffraction grating are arranged on the same plane, and the transmission type diffraction grating is tilted with respect to a direction perpendicular to the same plane. In the technique disclosed in Patent Document 1, the reflected first-order diffracted light emitted from the transmission type diffraction grating passes through a position shifted from the laser light source in a direction perpendicular to the same plane, so that it is possible to prevent the reflected first-order diffracted light from being irradiated onto the laser light source. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 2021-524161 Summary of the Invention [Problem to be solved by the invention]

[0006] However, as disclosed in Patent Document 1, when a transmission grating is tilted in a direction perpendicular to the same plane, the transmitted first-order diffracted light emitted from the transmission grating is twisted or tilted, which causes a problem of deteriorating the quality of the laser beam emitted from the output coupler.

[0007] The present disclosure has been made in consideration of the above, and aims to provide a laser device that can suppress damage to a light source caused by reflected first-order diffracted light while suppressing deterioration of the quality of a laser beam. [Means for solving the problem]

[0008] In order to solve the above problems and achieve the object, the laser device according to the present disclosure includes a plurality of laser light sources arranged side by side on the same plane, each having one or more light emitting points for emitting a laser beam, and an optical element for collimating the laser beam emitted from each of the plurality of laser light sources. The laser device according to the present disclosure also includes a transmission type diffraction grating for coaxially superimposing a portion of the laser beam emitted from the optical element and emitting the coaxially superimposed laser beam as a transmitted first-order diffracted light, and an output coupler for reflecting a portion of the transmitted first-order diffracted light emitted from the transmission type diffraction grating toward the laser light source and emitting the remaining portion of the transmitted first-order diffracted light emitted from the transmission type diffraction grating. The laser beams emitted from each of the plurality of laser light sources overlap at a position away from each laser light source. The transmission type diffraction grating is arranged at an overlapping position where the laser beams emitted from each of the plurality of laser light sources overlap, and is arranged parallel to a direction perpendicular to the same plane. Between two adjacent laser light sources among the plurality of laser light sources, a first gap is formed located on the optical path of the reflected first-order diffracted light emitted from the transmission diffraction grating. A first angle formed by a virtual line connecting a light emitting point disposed on one side of the first gap and closest to the first gap and the overlapping position, and a virtual line connecting a light emitting point disposed on the other side of the first gap and closest to the first gap and the overlapping position, is 0.15 degrees or more. Effect of the Invention

[0009] The laser device according to the present disclosure has an advantage in that it is possible to suppress damage to the light source caused by reflected first-order diffracted light, while suppressing deterioration of the quality of the laser beam. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram showing a laser processing apparatus including a laser device according to a first embodiment; [Diagram 2] FIG. 1 is a schematic diagram showing a laser device according to a first embodiment. [Diagram 3]FIG. 3 is a schematic diagram showing the laser device according to the first embodiment, as viewed along the Y-axis direction in FIG. [Figure 4] FIG. 1 is a perspective view for explaining the function of a first fast axis collimating lens and a slow axis collimating lens according to a first embodiment; [Diagram 5] FIG. 5 is a diagram for explaining the function of the first fast axis collimator lens according to the first embodiment, as viewed along the Y-axis direction in FIG. 4; [Figure 6] FIG. 5 is a diagram for explaining the function of the slow axis collimator lens according to the first embodiment, as viewed along the Z-axis direction in FIG. [Figure 7] FIG. 1 is a perspective view showing an example of a peripheral configuration of a laser light source according to a first embodiment; [Figure 8] FIG. 1 is a side view showing an example of a peripheral configuration of a laser light source according to a first embodiment; [Figure 9] FIG. 1 is a schematic diagram showing a laser device according to a second embodiment. [Figure 10] FIG. 13 is a schematic diagram showing a laser device according to a third embodiment. [Figure 11] FIG. 13 is a schematic diagram showing a laser device according to a fourth embodiment. [Figure 12] FIG. 13 is a schematic diagram showing a laser device according to a fifth embodiment. [Figure 13] FIG. 13 is a schematic diagram showing a laser device according to a sixth embodiment. [Figure 14] FIG. 13 is a schematic diagram showing a laser device according to a seventh embodiment. [Figure 15] FIG. 15 is a schematic diagram showing a laser device according to a seventh embodiment, as viewed along the Y-axis direction in FIG. [Figure 16] FIG. 13 is a schematic diagram showing a laser device according to an eighth embodiment. [Figure 17] FIG. 13 is a perspective view showing a beam rotating element of a laser device according to an eighth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A laser device and a laser processing device according to embodiments will be described in detail below with reference to the drawings.

[0012] Embodiment 1 FIG. 1 is a schematic diagram showing a laser processing apparatus 100 including a laser device 110 according to a first embodiment. The laser processing apparatus 100 processes a workpiece 140 by irradiating the workpiece 140 with a laser beam r. The processing includes, for example, cutting, welding, and drilling. The workpiece 140 is, for example, a metal plate or a substrate. The laser processing apparatus 100 includes the laser device 110, a propagation member 120, a processing head 130, and a processing table 150.

[0013] The laser device 110 emits a laser beam r. Details of the laser device 110 will be described later. The propagation member 120 propagates the laser beam r emitted from the laser device 110. The laser beam r emitted from the laser device 110 propagates to the processing head 130 via the propagation member 120. The propagation member 120 is, for example, a beam transmission optical path or an optical fiber.

[0014] The processing head 130 focuses the laser beam r propagated from the propagation member 120 and irradiates the laser beam r onto the workpiece 140. The workpiece 140 irradiated with the laser beam r is burned, melted, or sublimated. As a result, the workpiece 140 is subjected to processing such as cutting, welding, and drilling.

[0015] The processing table 150 holds the workpiece 140 and also plays a role in moving the position of the workpiece 140. The processing table 150 holds the workpiece 140 by, for example, adsorbing the workpiece 140. The processing table 150 is movable, for example, in two axial directions, and is capable of moving the workpiece 140 in the two axial directions. Note that the configuration of the laser processing device 100 shown in the figure is an example and may be changed as appropriate. For example, the laser device 110 may be applied to a 3D printer or the like by combining it with a commonly known laser processing device.

[0016] Next, the laser device 110 will be described in detail. FIG. 2 is a schematic diagram showing the laser device 110 according to the first embodiment. FIG. 3 is a schematic diagram showing the laser device 110 according to the first embodiment, and is a diagram when viewed along the Y-axis direction in FIG. 2. FIG. 4 is a perspective view for explaining the operation of the first fast-axis collimating lens 2 and the slow-axis collimating lens 3 according to the first embodiment. FIG. 5 is a diagram for explaining the operation of the first fast-axis collimating lens 2 according to the first embodiment, and is a diagram when viewed along the Y-axis direction in FIG. 4. FIG. 6 is a diagram for explaining the operation of the slow-axis collimating lens 3 according to the first embodiment, and is a diagram when viewed along the Z-axis direction in FIG. 4. In the following description, the directions are described according to the X-axis direction, the Y-axis direction, and the Z-axis direction shown in FIG. 2. The X-axis direction, the Y-axis direction, and the Z-axis direction shown in FIG. 2 are perpendicular to each other.

[0017] The laser device 110 includes a plurality of laser light sources 1, an optical element E, a transmission type diffraction grating 5, and an output coupler 6.

[0018] The laser light source 1 is a member that emits a laser beam r. The multiple laser light sources 1 are arranged side by side on the same plane, and have multiple light emitting points 1a that emit the laser beam r. In FIG. 2 and subsequent figures, for ease of understanding, the laser beam r emitted from each laser light source 1 is drawn with a single line, but in reality, multiple laser beams r are emitted from each of the multiple light emitting points 1a of each laser light source 1. The multiple laser light sources 1 are arranged in the XY plane. In the following description, the light emitting point 1a that is arranged on one side across the first gap 7 described below and closest to the first gap 7 is referred to as light emitting point 1b. Also, the light emitting point 1a that is arranged on the other side across the first gap 7 and closest to the first gap 7 is referred to as light emitting point 1c. Also, the light emitting point 1a that is arranged on one side across the first gap 7 and farthest from the first gap 7 is referred to as light emitting point 1d. Moreover, the light-emitting point 1a disposed on the other side of the first gap 7 and farthest from the first gap 7 is referred to as a light-emitting point 1e.

[0019] The laser beams r emitted from each of the multiple laser light sources 1 overlap at a position away from each laser light source 1. The laser beams r overlap on the transmission grating 5. Hereinafter, the position where the laser beams r overlap is referred to as the overlapping position S. The overlapping of the laser beams r on the transmission grating 5 includes a state where the laser beams r overlap at one point on the transmission grating 5, as well as a state where the laser beams r are close to each other on the transmission grating 5. The close state refers to a state where the laser beams r are close enough to each other that the first-order light of each laser beam r can be overlapped on the same axis by the diffraction of each laser beam r in the transmission grating 5. In this embodiment, the multiple laser light sources 1 are arranged on one arc centered on the overlapping position S, but they may be arranged on approximately one arc centered on the overlapping position S. In addition, in the present disclosure, the arrangement on approximately one arc means that a certain error is allowed in the arrangement of the laser light sources 1. And, the range of the certain error means a range in which the effect of the present disclosure can be achieved. That is, the position of the laser light source 1 may deviate from one arc centered on the overlapping position S as long as the laser beam r having the necessary characteristics can be obtained by superimposing the laser beams r emitted from each of the multiple light emitting points 1a for the purpose of laser processing such as cutting and welding. Therefore, even if there is a deviation of the laser light source 1 due to the requirements of the optical design, a processing tolerance occurring during the manufacture of the product, or a deviation of the laser light source 1 due to the arrangement work, it is considered to be included in the range of approximately one arc. When the change in the output of the laser beam r, the quality of the laser beam r, etc. is examined by changing the distance of the laser light source 1 from the overlapping position S, in many cases, a variation of at least about ±5% is acceptable for the distance of the laser light source 1 from the overlapping position S. Here, the deviation of the laser light source 1 due to the requirements of the optical design is a deviation of the distance of each laser light source 1 from the overlapping position S that is intentionally set in the optical design in order to equalize the optical operating characteristics of the multiple laser light sources 1.

[0020] In this embodiment, the laser light source 1 is a semiconductor laser bar. The laser light source 1 shown in FIG. 2 is a semiconductor laser array element having a plurality of light emitting points 1a that emit a laser beam r. The number of light emitting points 1a of each laser light source 1 is three in this embodiment, but may be changed as appropriate. The laser light sources 1 are arranged on one side and the other side of a first gap 7 described later. The number of laser light sources 1 is five in this embodiment, but may be a number other than five. It is sufficient that at least one laser light source 1 is arranged on one side and the other side of the first gap 7.

[0021] A first gap 7 is formed between two adjacent laser light sources 1 among the multiple laser light sources 1. The first gap 7 is located on the optical path of the reflected first-order diffracted light r2 emitted from the transmission diffraction grating 5. In this embodiment, the first gap 7 is formed between the third laser light source 1 from the top of the paper in Fig. 2 and the fourth laser light source 1 from the top of the paper in Fig. 2, but the position of the first gap 7 is appropriately changed depending on the number of laser light sources 1 and the optical path of the reflected first-order diffracted light r2.

[0022] A virtual line C1 is a virtual line connecting the light emitting point 1b, which is disposed on one side of the first gap 7 and is closest to the first gap 7, and the overlapping position S. Meanwhile, a virtual line C2 is a virtual line connecting the light emitting point 1c, which is disposed on the other side of the first gap 7 and is closest to the first gap 7, and the overlapping position S. The first angle θ1 formed by the virtual lines C1 and C2 is 0.15 degrees or more. In addition, it is preferable that the first angle θ1 is 1.0 degrees or less. A virtual line C3 is a virtual line connecting the light emitting point 1d, which is disposed on one side of the first gap 7 and is farthest from the first gap 7, and the overlapping position S. Meanwhile, a virtual line C4 is a virtual line connecting the light emitting point 1e, which is disposed on the other side of the first gap 7 and is farthest from the first gap 7, and the overlapping position S. It is preferable that the second angle θ2 formed by the virtual lines C3 and C4 is 5 degrees or more.

[0023] The optical element E is a member that collimates the laser beam r emitted from each of the multiple laser light sources 1. The optical element E serves to reduce the variation in the angle of incidence of each laser beam r incident on the transmission diffraction grating 5. The laser device 110 includes the optical element E, so that the utilization efficiency of the laser beam r can be improved. The optical element E has a plurality of first fast axis collimating lenses 2, a plurality of slow axis collimating lenses 3, and a second fast axis collimating lens 4. The first fast axis collimating lens 2, the plurality of slow axis collimating lenses 3, and the second fast axis collimating lens 4 are cylindrical lenses.

[0024] The multiple first fast axis collimating lenses 2 are members provided for each of the multiple laser light sources 1 and collimate the laser beam r emitted from each of the multiple laser light sources 1 in the fast axis direction. The multiple first fast axis collimating lenses 2 are provided for each of the multiple laser light sources 1. In this embodiment, the fast axis direction is parallel to the Z axis direction. As shown in FIG. 4 and FIG. 5, the first fast axis collimating lens 2 reduces the divergence angle of the laser beam r in the Z axis direction.

[0025] As shown in FIG. 2, the slow-axis collimating lenses 3 are provided for each of the laser light sources 1, and are members that collimate the laser beam r emitted from each of the first fast-axis collimating lenses 2 in the slow-axis direction. The slow-axis collimating lenses 3 are provided for each of the laser light sources 1. In this embodiment, the slow-axis direction is the direction in which the light-emitting points 1a are lined up in the XY plane. In FIG. 2, the slow-axis direction is illustrated by the arrow Sa. As shown in FIG. 4 and FIG. 6, the slow-axis collimating lens 3 reduces the divergence angle of the laser beam r in the slow-axis direction.

[0026] As shown in Fig. 2, the second fast axis collimating lens 4 is a member that collimates the laser beam r emitted from each of the multiple slow axis collimating lenses 3 in the fast axis direction. That is, the second fast axis collimating lens 4 recollimates each laser beam r that has expanded in the fast axis direction after being emitted from each of the multiple slow axis collimating lenses 3 in the fast axis direction. The laser beam r emitted from each of the multiple slow axis collimating lenses 3 is incident on the second fast axis collimating lens 4. The second fast axis collimating lens 4, like the first fast axis collimating lens 2, reduces the divergence angle of the laser beam r in the Z axis direction.

[0027] The transmission grating 5 is a member that coaxially superimposes a part of the laser beam r emitted from the optical element E and emits the coaxially superimposed laser beam r as transmitted first-order diffracted light r1. The transmission grating 5 diffracts each of the multiple laser beams r emitted from the optical element E in the XY plane by wavelength dispersion and separates it into each order. The transmission grating 5 coaxially superimposes each first-order light of the multiple laser beams r and emits it as transmitted first-order diffracted light r1. The transmitted first-order diffracted light r1 is emitted toward the output coupler 6. The transmission grating 5 also emits reflected first-order diffracted light r2 in a direction different from the emission direction of the transmitted first-order diffracted light r1. The reflected first-order diffracted light r2 is emitted toward the laser light source 1.

[0028] The transmission grating 5 is disposed at an overlapping position S where the laser beams r emitted from the respective laser light sources 1 overlap. The transmission grating 5 is inclined in the X-axis direction and the Y-axis direction in the XY plane. As shown in FIG. 3, the laser light source 1 and the transmission grating 5 are disposed on the same plane in the XY plane. The transmission grating 5 is disposed parallel to a direction perpendicular to the same plane on which the multiple laser light sources 1 are disposed. In this embodiment, the direction perpendicular to the same plane is the Z-axis direction. The transmission grating 5 is disposed parallel to the Z-axis direction. In this embodiment, the laser light source 1, the first fast axis collimating lens 2, the slow axis collimating lens 3, the second fast axis collimating lens 4, the transmission grating 5, and the output coupler 6 are disposed on the same plane in the XY plane.

[0029] As shown in Fig. 2, the output coupler 6 is a member that reflects a part of the transmitted first-order diffracted light r1 emitted from the transmission grating 5 toward the laser light source 1 and emits the remaining part of the transmitted first-order diffracted light r1 emitted from the transmission grating 5. Fig. 2 shows only the remaining part of the transmitted first-order diffracted light r1 emitted from the output coupler 6. The output coupler 6 is, for example, a partial reflection mirror.

[0030] The multiple laser light sources 1 and the output coupler 6 form a resonator. The laser beam r emitted from the multiple laser light sources 1 is amplified by repeatedly reflecting between the laser light sources 1 and the output coupler 6. A part of the amplified laser beam r is emitted from the output coupler 6 to the outside of the laser device 110 and propagates to the processing head 130 via the propagation member 120 shown in FIG.

[0031] Next, the configuration of the laser light source 1 and the first fast axis collimator lens 2 will be described with reference to Fig. 7 and Fig. 8. Fig. 7 is a perspective view showing an example of the configuration of the laser light source 1 according to the first embodiment. Fig. 8 is a side view showing an example of the configuration of the laser light source 1 according to the first embodiment.

[0032] As shown in FIGS. 7 and 8, around the laser light source 1 and the first fast axis collimator lens 2, a first power supply member 8, a second power supply member 10, an insulating plate 11, and an electric wire 12 are arranged.

[0033] As shown in FIG. 7, the first power supply member 8 is a member that supplies power to the laser light source 1. The shape of the first power supply member 8 is a rectangular parallelepiped in this embodiment, but may be changed as appropriate. The laser light source 1 is installed on one end surface of the first power supply member 8 in the Z-axis direction. The first fast axis collimator lens 2 is fixed to one end surface of the first power supply member 8 in the X-axis direction by an adhesive or the like. The first fast axis collimator lens 2 covers the emission surface of the laser light source 1. As shown in FIG. 8, a cooling mechanism 9 for cooling the laser light source 1 is provided inside the first power supply member 8. The cooling mechanism 9 is, for example, a cooling water channel through which cooling water flows.

[0034] As shown in FIG. 7, the second power supply member 10 is a member that supplies power to the laser light source 1. The shape of the second power supply member 10 is a rectangular parallelepiped in this embodiment, but may be changed as appropriate. The size of the second power supply member 10 is smaller than that of the first power supply member 8. The second power supply member 10 is installed on one end surface of the first power supply member 8 in the Z-axis direction. The second power supply member 10 and the laser light source 1 are installed apart from each other in the X-axis direction. The second power supply member 10 and the laser light source 1 are electrically connected via a plurality of electric wires 12. An insulating plate 11 that electrically insulates the first power supply member 8 and the second power supply member 10 is installed between them. Note that the configuration around the laser light source 1 and the first fast axis collimator lens 2 shown in the figure is an example, and may be changed as appropriate.

[0035] Next, the effects of the laser device 110 according to this embodiment will be described.

[0036] In this embodiment, as shown in Fig. 2, a first gap 7 is formed between two adjacent laser light sources 1 among the plurality of laser light sources 1, the first gap 7 being located on the optical path of the reflected first-order diffracted light r2 emitted from the transmission grating 5. In this embodiment, the first angle θ1 formed by a virtual straight line C1 connecting the light emitting point 1b, which is disposed on one side of the first gap 7 and closest to the first gap 7, and the overlapping position S, and a virtual straight line C2 connecting the light emitting point 1c, which is disposed on the other side of the first gap 7 and closest to the first gap 7, and the overlapping position S, is 0.15 degrees or more. With these configurations, the reflected first-order diffracted light r2 does not pass through the first gap 7 and is not irradiated to the laser light source 1, so that damage to the laser light source 1 caused by the reflected first-order diffracted light r2 can be suppressed. In addition, with the above-mentioned configuration, the reflected first-order diffracted light r2 does not pass through the first gap 7 and is not irradiated to the first fast-axis collimating lens 2 and the slow-axis collimating lens 3, so that damage to the first fast-axis collimating lens 2 and the slow-axis collimating lens 3 due to the reflected first-order diffracted light r2 can also be suppressed. According to the experiments and research of the present applicant, it has been found that the optical path of the reflected first-order diffracted light r2 changes due to the influence of the positional deviation, the angle deviation, etc. of the laser light source 1 and the optical element E. When the first angle θ1 is 0.15 degrees or more as in the present embodiment, even if the optical path of the reflected first-order diffracted light r2 changes due to the influence of the positional deviation, the angle deviation, etc., the reflected first-order diffracted light r2 passes through the first gap 7, so that it is possible to suppress the reflected first-order diffracted light r2 from being irradiated to the laser light source 1. On the other hand, when the first angle θ1 is 1.0 degree or less, the increase in the first gap 7 can be suppressed, and the multiple laser light sources 1 can be arranged compactly, so that it is possible to suppress the increase in size of the laser device 110.

[0037] In order to increase the output of the laser beam r, it is necessary to suppress the reflected first-order diffracted light r2 from being irradiated at least onto the laser light source 1. On the other hand, it is preferable to prevent the reflected first-order diffracted light r2 from being irradiated onto the first power supply member 8, the second power supply member 10, the cooling mechanism 9, and the like, which are arranged around the laser light source 1 shown in Figs. 7 and 8. It is also preferable to prevent the reflected first-order diffracted light r2 from being irradiated onto the adhesive of the fixing portion of the first fast axis collimator lens 2 in the first power supply member 8. In order to prevent the reflected first-order diffracted light r2 from being irradiated onto the first power supply member 8, and the like, which are arranged around the laser light source 1, the first angle θ1 shown in Fig. 2 may be appropriately adjusted.

[0038] 3, in this embodiment, the transmission grating 5 is arranged parallel to a direction perpendicular to the same plane on which the multiple laser light sources 1 are arranged. With this configuration, the transmitted first-order diffracted light r1 emitted from the transmission grating 5 is less likely to be twisted or tilted, so that the quality of the laser beam r emitted from the output coupler 6 can be improved. In other words, in this embodiment, a laser device 110 can be obtained that can suppress damage to the laser light source 1 caused by the reflected first-order diffracted light r2 while suppressing deterioration in the quality of the laser beam r.

[0039] 2, in this embodiment, the laser light sources 1 are arranged on both sides of the first gap 7. With this configuration, the number of laser light sources 1 can be increased compared to the case where the laser light sources 1 are arranged only on one side of the first gap 7, and therefore the total output of the laser beam r can be increased.

[0040] In this embodiment, the laser light source 1 is a semiconductor laser array element having a plurality of light emitting points 1a, as shown in Fig. 2. With this configuration, it is possible to realize high output of the laser beam r of the laser device 110.

[0041] In this embodiment, as shown in FIG. 2, the optical element E has a configuration including a plurality of first fast-axis collimating lenses 2, a plurality of slow-axis collimating lenses 3, and a second fast-axis collimating lens 4. This configuration can reduce the variation in the incident angle of each laser beam r incident on the transmission diffraction grating 5, thereby improving the utilization efficiency of the laser beam r. On the other hand, the configuration of the optical element E described above makes it easier for the reflected first-order diffracted light r2 to be focused toward the laser light source 1, which is a disadvantage in that the reflected first-order diffracted light r2 is more likely to damage the laser light source 1. In this regard, in this embodiment, the first gap 7 located on the optical path of the reflected first-order diffracted light r2 is formed, and the first angle θ1 is 0.15 degrees or more, so that the reflected first-order diffracted light r2 does not pass through the first gap 7 and is not irradiated to the laser light source 1, thereby suppressing damage to the laser light source 1 due to the reflected first-order diffracted light r2. In other words, the disadvantages due to the configuration of the optical element E described above can be eliminated. As a result, in this embodiment, it is possible to increase the utilization efficiency of the laser beam r to realize a high output of the laser beam r from the laser device 110, while suppressing damage to the laser light source 1 caused by the reflected first-order diffracted light r2.

[0042] The laser device 110 according to the present embodiment is preferably used to realize high output of the laser beam r in the Wavelength Beam Combining (WBC) technology. When the laser device 110 according to the present embodiment is used for such a purpose, it is preferable to satisfy the following four conditions. (1) The output of the laser beam r emitted from the output coupler 6 is 2 kW or more. (2) The number of laser light sources 1 is 12 or more. (3) The diffraction angle of the transmitted first-order diffracted light r1 emitted from the transmission type diffraction grating 5 is 60 degrees or more. (4) The second angle θ2 of the laser beam r incident on the transmission diffraction grating 5 is 5 degrees or more.

[0043] First, the basis of the above-mentioned condition (1) will be explained. The reflected first-order diffracted light r2 has an output equivalent to about 1% of the output of the laser beam r outputted from the output coupler 6. According to the applicant's experiments and research, it has been found that when the output of the reflected first-order diffracted light r2 exceeds 20 W, damage to the laser light source 1 and the like becomes evident. For this reason, it is preferable that the output of the laser beam r outputted from the output coupler 6 is 2 kW or more.

[0044] Next, the basis of the condition (2) described above will be explained. As a laser light source 1 that enables high output suitable for laser processing in the wavelength beam combining technology, a semiconductor laser bar in which multiple light emitting points 1a are integrally formed on a semiconductor chip with a width of 10 mm is useful and common. The upper limit of the output of semiconductor laser bars available on the market is currently about 200 W. When using a semiconductor laser bar in the wavelength beam combining technology, the output of the laser beam r emitted from the output coupler 6 is reduced by about 20% from the output of the semiconductor laser bar. Considering this reduction, in order for the output of the laser beam r emitted from the output coupler 6 to be 2 kW or more, the number of semiconductor laser bars is preferably 12.5 from the following formula (1), and more preferably 12 or more, omitting the decimal point. 2kW / (200W×0.8)=12.5 (1)

[0045] Next, the basis of the condition (3) described above will be explained. In order to combine the wavelength beams of the laser beam r in a narrower wavelength range, it is preferable to increase the diffraction angle of the transmitted first-order diffracted light r1 to increase the wavelength resolution. For example, the theoretical limit of the transmission type diffraction grating 5 applicable to the laser beam r having a wavelength of about 980 nm in the near infrared region is a number of grooves of about 2000 / mm, and the limit of the number of grooves of products available on the market is a number of grooves of about 1850 / mm. When a transmission type diffraction grating 5 having a number of grooves of about 1850 / mm is used, the diffraction angle of the transmission type diffraction grating 5 at which the diffraction efficiency of the transmission type diffraction grating 5 is maximized is about 65 degrees. For this reason, it is preferable that the diffraction angle of the transmitted first-order diffracted light r1 emitted from the transmission type diffraction grating 5 is 60 degrees or more. The numerical value of the diffraction angle of the transmission type diffraction grating 5 under this condition will be the same even if the wavelength band used is changed to, for example, about 450 nm of a blue laser.

[0046] Finally, the basis of the condition (4) will be described. For example, in a configuration in which the diffraction angle of the transmitted first-order diffracted light r1 is 60 degrees and the second angle θ2 is less than 5 degrees, the incident angle of the laser beam r to the transmission grating 5 is set in the range of 55 degrees to 59 degrees, so that efficient wavelength beam combining can be performed while suppressing the reflected first-order diffracted light r2 from being irradiated onto the laser light source 1. However, in order for the output of the laser beam r output from the output coupler 6 in this configuration to be 2 kW or more, the distance between the laser light source 1 and the transmission grating 5 needs to be 2 m or more, and considering the size of the laser device 110 for the laser processing device 100, it is difficult to achieve a distance of 2 m or more between the laser light source 1 and the transmission grating 5. For this reason, the second angle θ2 of the laser beam r incident on the transmission grating 5 is preferably 5 degrees or more.

[0047] Next, a modification of the first embodiment will be described.

[0048] 2 is a semiconductor laser array element, it may be a semiconductor laser bar other than the semiconductor laser array element. The laser light source 1 may be, for example, an edge-emitting type semiconductor laser bar having one light-emitting point 1a, or a surface-emitting type semiconductor laser bar having one or more light-emitting points 1a.

[0049] 2 includes a plurality of first fast axis collimating lenses 2, a plurality of slow axis collimating lenses 3, and a second fast axis collimating lens 4, but the configuration of the optical element E may be changed as appropriate. For example, the second fast axis collimating lens 4 may be omitted from the optical element E.

[0050] Embodiment 2 Next, a laser device 110A according to a second embodiment will be described with reference to Fig. 9. Fig. 9 is a schematic diagram showing the laser device 110A according to the second embodiment. This embodiment differs from the first embodiment in that the laser device 110A further includes an output monitor member 13. In the second embodiment, the same reference numerals are used for parts that overlap with the first embodiment, and descriptions thereof will be omitted.

[0051] The output monitor member 13 is a member disposed in the first gap 7 and measures the output fluctuation of the reflected first-order diffracted light r2. The output monitor member 13 is, for example, a thermopile sensor. The output monitor member 13 has an incident surface 13a on which the reflected first-order diffracted light r2 is incident. The incident surface 13a is a flat surface parallel to the Z-axis direction and the Y-axis direction. The incident surface 13a is a surface perpendicular to the optical axis of the reflected first-order diffracted light r2.

[0052] Next, the effects of the laser device 110A according to this embodiment will be described.

[0053] In this embodiment, the laser device 110A further includes an output monitor member 13 disposed in the first gap 7 for measuring output fluctuations of the reflected first-order diffracted light r2. With this configuration, it is possible to indirectly monitor output fluctuations of the transmitted first-order diffracted light r1 by utilizing the reflected first-order diffracted light r2, which has a lower output than the transmitted first-order diffracted light r1.

[0054] The output monitor member 13 may be a photodiode, which makes it possible to measure the output fluctuation of the reflected first-order diffracted light r2 at high speed.

[0055] Embodiment 3 Next, a laser device 110B according to a third embodiment will be described with reference to FIG. 10. FIG. 10 is a schematic diagram showing a laser device 110B according to a third embodiment. This embodiment differs from the first and second embodiments in that the laser device 110B further includes a shielding member 14. In the third embodiment, the same reference numerals are used for parts that overlap with the first and second embodiments, and descriptions thereof will be omitted. In FIG. 10, members other than the output monitor member 13 and the shielding member 14 are omitted.

[0056] The shielding member 14 is disposed on the output monitor member 13 and surrounds the periphery of the incident surface 13a. The shielding member 14 is a cylindrical member extending along the periphery of the incident surface 13a. The shielding member 14 serves to block light M that is obliquely incident on the incident surface 13a of the output monitor member 13. The obliquely incident light M is scattered light around the output monitor member 13, and is not the light to be measured by the output monitor member 13.

[0057] Next, the effects of the laser device 110B according to this embodiment will be described.

[0058] In this embodiment, the laser device 110B further includes a shielding member 14 that is installed on the output monitor member 13 and surrounds the periphery of the incident surface 13a. This configuration can block the light M that is obliquely incident on the incident surface 13a of the output monitor member 13, thereby improving the measurement accuracy of the output fluctuation of the reflected first-order diffracted light r2.

[0059] Embodiment 4 Next, a laser device 110C according to a fourth embodiment will be described with reference to FIG. 11. FIG. 11 is a schematic diagram showing the laser device 110C according to the fourth embodiment. This embodiment differs from the first to third embodiments in that the laser device 110C further includes an object-side telecentric lens 15. In the fourth embodiment, the same reference numerals are used for parts that overlap with the first to third embodiments, and descriptions thereof will be omitted. In FIG. 11, members other than the output monitor member 13 and the object-side telecentric lens 15 are omitted.

[0060] The object-side telecentric lens 15 is disposed on the incident surface 13a of the output monitor member 13 and is a member that transmits only the reflected first-order diffracted light r2 that is perpendicularly incident on the incident surface 13a. The object-side telecentric lens 15 serves to cut off the light M that is obliquely incident on the incident surface 13a.

[0061] Next, the effects of the laser device 110C according to this embodiment will be described.

[0062] In this embodiment, the laser device 110C further includes an object-side telecentric lens 15 that is disposed on the incident surface 13a of the output monitor member 13 and transmits only the reflected first-order diffracted light r2 that is perpendicularly incident on the incident surface 13a. This configuration can cut off the light M that is obliquely incident on the incident surface 13a of the output monitor member 13, thereby improving the measurement accuracy of the output fluctuation of the reflected first-order diffracted light r2.

[0063] Embodiment 5. Next, a laser device 110D according to a fifth embodiment will be described with reference to FIG. 12. FIG. 12 is a schematic diagram showing a laser device 110D according to a fifth embodiment. This embodiment differs from the first to fifth embodiments in that the laser device 110D further includes a light-attenuating optical element 16. In the fifth embodiment, the same reference numerals are used for parts that overlap with the first to fourth embodiments, and descriptions thereof will be omitted. In FIG. 12, members other than the output monitor member 13 and the light-attenuating optical element 16 are omitted.

[0064] The light-attenuating optical element 16 is a member that is disposed between the incident surface 13a of the output monitor member 13 and the transmission type diffraction grating 5 shown in Fig. 9, and attenuates the light intensity of the reflected first-order diffracted light r2 incident on the output monitor member 13. The light-attenuating optical element 16 is disposed ahead of the second fast axis collimator lens 4 shown in Fig. 9 in the traveling direction of the reflected first-order diffracted light r2. In this embodiment, the light-attenuating optical element 16 is disposed on the incident surface 13a of the output monitor member 13. The light-attenuating optical element 16 is, for example, an ND (Neutral Density) filter or a partial reflection mirror.

[0065] Next, the effects of the laser device 110D according to this embodiment will be described.

[0066] In this embodiment, the laser device 110D further includes a light-attenuating optical element 16 that is disposed between the incident surface 13a of the output monitor member 13 and the transmission diffraction grating 5 and attenuates the light intensity of the reflected first-order diffracted light r2 incident on the output monitor member 13. With this configuration, it is possible to measure the output fluctuation of the reflected first-order diffracted light r2 while suppressing damage to the output monitor member 13 caused by the reflected first-order diffracted light r2.

[0067] When a photodiode having a lower upper limit of the amount of incident light compared to a thermopile sensor or the like is used as the output monitor member 13, it is advisable to use the photodiode in combination with the light-reducing optical element 16. In this way, the amount of reflected first-order diffracted light r2 can be attenuated by the light-reducing optical element 16 before the reflected first-order diffracted light r2 enters the photodiode. Therefore, the output fluctuation of the reflected first-order diffracted light r2 can be appropriately measured by the photodiode.

[0068] It is also possible to use the light-attenuating optical element 16 in combination with the object-side telecentric lens 15 shown in Fig. 11. In such a configuration, it is preferable to arrange the light-attenuating optical element 16, the object-side telecentric lens 15, and the output monitor member 13 in this order along the traveling direction of the reflected first-order diffracted light r2. In other words, it is preferable that the light-attenuating optical element 16 is disposed on the entrance surface 13a of the output monitor member 13 via the object-side telecentric lens 15.

[0069] Embodiment 6 Next, a laser device 110E according to a sixth embodiment will be described with reference to Fig. 13. Fig. 13 is a schematic diagram showing a laser device 110E according to a sixth embodiment. This embodiment differs from the first to fifth embodiments in that the laser device 110E further includes a damper 17. In the sixth embodiment, the same reference numerals are used for parts that overlap with the first to fifth embodiments, and descriptions thereof will be omitted.

[0070] The damper 17 is a member that is disposed in the first gap 7 and absorbs the reflected first-order diffracted light r2.

[0071] Next, the effects of the laser device 110E according to this embodiment will be described.

[0072] In this embodiment, the laser device 110E further includes a damper 17 disposed in the first gap 7 to absorb the reflected first-order diffracted light r2. This configuration can suppress the generation of stray light due to the reflected first-order diffracted light r2, and can also suppress heating of components in the laser device 110E due to the reflected first-order diffracted light r2.

[0073] Embodiment 7 Next, a laser device 110F according to a seventh embodiment will be described with reference to FIG. 14 and FIG. 15. FIG. 14 is a schematic diagram showing the laser device 110F according to the seventh embodiment. FIG. 15 is a schematic diagram showing the laser device 110F according to the seventh embodiment, as viewed along the Y-axis direction in FIG. 14. This embodiment is different from the first to sixth embodiments in that the laser light source 1, the first fast-axis collimating lens 2, the slow-axis collimating lens 3, the second fast-axis collimating lens 4, the transmission grating 5, and the output coupler 6 are not arranged on the same plane, and the laser device 110F further includes a mirror 18. In addition, in the seventh embodiment, the same reference numerals are used for the parts that overlap with the first to sixth embodiments, and the description thereof will be omitted.

[0074] 15, the laser light source 1, the first fast axis collimating lens 2, and the slow axis collimating lens 3 are arranged to be shifted in the Z-axis direction, which is a direction perpendicular to the second fast axis collimating lens 4, the transmission diffraction grating 5, and the output coupler 6. The laser light source 1, the first fast axis collimating lens 2, and the slow axis collimating lens 3 are tilted with respect to the Z-axis direction. The optical axis of the laser beam r emitted from each of the laser light source 1, the first fast axis collimating lens 2, and the slow axis collimating lens 3 is tilted with respect to the Z-axis direction.

[0075] The mirror 18 is disposed between the slow axis collimator lens 3 and the second fast axis collimator lens 4. The mirror 18 reflects the laser beam r emitted from the slow axis collimator lens 3 toward the second fast axis collimator lens 4. The mirror 18 is inclined so as to move away from the slow axis collimator lens 3 in the Z-axis direction as it moves from the slow axis collimator lens 3 toward the second fast axis collimator lens 4.

[0076] As shown in Fig. 14, the mirror 18 is divided into two in a direction intersecting the optical axis of the laser beam r emitted from each of the multiple slow-axis collimating lenses 3. In this embodiment, the mirror 18 is divided into two in the Y-axis direction. A second gap 19 is formed between two adjacent mirrors 18 and is located on the optical path of the reflected first-order diffracted light r2. The first gap 7 and the second gap 19 are aligned in the Y-axis direction. The first gap 7 and the second gap 19 are misaligned in the X-axis direction and the Z-axis direction.

[0077] Next, the effects of the laser device 110F according to this embodiment will be described.

[0078] In this embodiment, as shown in FIG. 15, the laser light source 1, the first fast axis collimating lens 2, and the slow axis collimating lens 3 are arranged to be shifted in the Z-axis direction with respect to the second fast axis collimating lens 4, the transmission type diffraction grating 5, and the output coupler 6. In this embodiment, the laser device 110F further includes a mirror 18 arranged between the slow axis collimating lens 3 and the second fast axis collimating lens 4 to reflect the laser beam r emitted from the slow axis collimating lens 3 toward the second fast axis collimating lens 4. In this embodiment, as shown in FIG. 14, the mirror 18 is divided into two, and a second gap 19 located on the optical path of the reflected first-order diffracted light r2 is formed between the two adjacent mirrors 18. With these configurations, as shown in FIG. 15, the reflected first-order diffracted light r2 passes through a position shifted from the laser light source 1 in the Z-axis direction, so that the reflected first-order diffracted light r2 can be prevented from being irradiated onto the laser light source 1. Therefore, damage to the laser light source 1 caused by the reflected first-order diffracted light r2 can be suppressed.

[0079] When the output monitor member 13 or the damper 17 is installed, the output monitor member 13 or the damper 17 is installed ahead of the second gap 19 in the traveling direction of the reflected first-order diffracted light r2. With this configuration, the reflected first-order diffracted light r2 emitted from the transmission grating 5 passes through the second gap 19 and then enters the output monitor member 13 or the damper 17. Therefore, even when the mirror 18 is provided, it becomes easy to monitor the output fluctuation of the reflected first-order diffracted light r2 by the output monitor member 13, and it becomes easy to absorb the reflected first-order diffracted light r2 by the damper 17. Although not shown in the figure, it is also possible to use three or more mirrors 18 to arrange the laser light source 1, the first fast axis collimating lens 2, and the slow axis collimating lens 3 so as not to be shifted in the Z-axis direction, which is a direction perpendicular to the second fast axis collimating lens 4, the transmission grating 5, and the output coupler 6.

[0080] Embodiment 8 Next, a laser device 110G according to an eighth embodiment will be described with reference to Fig. 16 and Fig. 17. Fig. 16 is a schematic diagram showing the laser device 110G according to the eighth embodiment. Fig. 17 is a perspective view showing a beam rotation element 20 of the laser device 110G according to the eighth embodiment. This embodiment differs from the first to seventh embodiments in that the laser device 110G further includes a beam rotation element 20. In the eighth embodiment, the same reference numerals are used for parts that overlap with the first to seventh embodiments, and description thereof will be omitted.

[0081] As shown in Fig. 16, the beam rotation element 20 is disposed between the first fast axis collimator lens 2 and the slow axis collimator lens 3. The beam rotation element 20 serves to rotate the laser beam r by 90 degrees around the optical axis of the laser beam r. That is, as shown in Fig. 17, the beam rotation element 20 is a rotation optical system that rotates an image by 90 degrees around the optical axis of the laser beam r. The beam rotation element 20 shown in Fig. 17 is a lens array having a plurality of lenses.

[0082] As shown in FIG. 16 and FIG. 17, a surface of the beam rotation element 20 facing the first fast axis collimating lens 2 and a surface facing the opposite side to the first fast axis collimating lens 2 each have a plurality of cylindrical surfaces arranged in one direction. Each cylindrical surface is a convex surface. Each cylindrical surface is inclined at 45 degrees with respect to a vertical axis Va perpendicular to the horizontal axis Ha. The arrangement pitch of the plurality of lenses is the same as the arrangement pitch of the plurality of light emitting points 1a in the laser light source 1. When the focal length due to refraction on the cylindrical surface is f, the distance L between the cylindrical surface facing the first fast axis collimating lens 2 and the cylindrical surface facing the opposite side to the first fast axis collimating lens 2 is 2f.

[0083] The long axis direction of the incident light, which is the laser beam r incident on the beam rotation element 20 from the first fast axis collimator lens 2, is the direction of the vertical axis Va. The short axis direction of the incident light is the direction of the horizontal axis Ha. In contrast, the long axis direction of the outgoing light, which is the laser beam r incident on the beam rotation element 20 from the first fast axis collimator lens 2 and then emitted from the beam rotation element 20, is the direction of the horizontal axis Ha. The short axis direction of the outgoing light is the direction of the vertical axis Va. In this way, the beam rotation element 20 emits outgoing light whose long axis and short axis directions are interchanged with those of the incident light. In this way, the beam rotation element 20 rotates the laser beam r by 90 degrees around the optical axis of the laser beam r.

[0084] For example, when the laser light source 1 is a semiconductor laser bar that emits a laser beam r of 900 nm to 1000 nm, the total angle of the divergence angle of the laser beam r in the slow axis direction is generally about 5 degrees to 10 degrees, whereas the total angle of the divergence angle of the laser beam r in the fast axis direction is about 30 degrees to 60 degrees. That is, the divergence angle of the laser beam r in the fast axis direction is larger than the divergence angle of the laser beam r in the slow axis direction. Also, the focusing performance of the semiconductor laser bar in the slow axis direction is lower than the focusing performance of the semiconductor laser bar in the fast axis direction.

[0085] The focusing performance referred to here is a characteristic expressed as BPP (Beam Parameter Product). BPP is an index defined as the product of the radius of the beam waist when focused and the half angle of the beam divergence after focusing. The unit of BPP is expressed in mm mrad. The smaller the BPP value, the higher the focusing ability, meaning that the laser beam r can be focused on a smaller area. The more the laser beam r can be focused on a smaller area, the higher the energy density that can be obtained. In laser processing applications, the higher the energy density, the better the processing quality and processing speed can be improved.

[0086] A semiconductor laser bar may have a deformation called a smile due to the manufacturing process of the semiconductor laser bar. The smile causes the positions of the multiple light emitting points 1a to vary in the fast axis direction. According to this embodiment, the beam rotation element 20 rotates the laser beam r by 90 degrees around the optical axis of the laser beam r, so that the direction in which the positions of the light emitting points 1a vary due to the smile is converted to the slow axis direction in which the focusing performance is relatively poor. This makes it possible to reduce the deterioration of the focusing performance caused by the smile.

[0087] For example, when a first fast axis collimating lens 2 made of a lens having a cylindrical surface is used, the first fast axis collimating lens 2 is installed at a slight inclination with respect to the XY plane, so that the laser beam r is emitted from the first fast axis collimating lens 2 with an angle in the Z axis direction. When a beam rotating element 20 is installed immediately after the first fast axis collimating lens 2, the laser beam r is converted from an angle in the Z axis direction to an angle in the XY plane by passing through the beam rotating element 20. By appropriately setting the inclination angle of the first fast axis collimating lens 2 with respect to the XY plane, the laser beams r can be brought closer to each other while traveling toward the transmission type diffraction grating 5.

[0088] Next, the effects of the laser device 110G according to this embodiment will be described.

[0089] In this embodiment, the laser device 110G further includes a beam rotation element 20 that is disposed between the first fast axis collimating lens 2 and the slow axis collimating lens 3 and rotates the laser beam r by 90 degrees around the optical axis of the laser beam r. This configuration provides the laser device 110G that can realize high output of the laser beam r while reducing the deterioration of the focusing performance caused by the smile.

[0090] The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies, or the embodiments may be combined with each other. Also, parts of the configurations may be omitted or modified without departing from the spirit of the invention. [Explanation of symbols]

[0091] 1 laser light source, 1a, 1b, 1c, 1d, 1e light emitting point, 2 first fast axis collimating lens, 3 slow axis collimating lens, 4 second fast axis collimating lens, 5 transmission type diffraction grating, 6 output coupler, 7 first gap, 8 first power supply member, 9 cooling mechanism, 10 second power supply member, 11 insulating plate, 12 electric wire, 13 output monitor member, 13a incident surface, 14 shielding member, 15 object side telecentric lens, 16 dimming optical element, 17 damper, 18 mirror, 19 second gap, 20 beam rotation element, 100 laser processing device, 110, 110A, 110B, 110C, 110D, 110E, 110F, 110G laser device, 120 propagation member, 130 processing head, 140 Workpiece, 150 machining table, C1, C2, C3, C4 virtual line, E optical element, r laser beam, r1 transmitted first-order diffracted light, r2 reflected first-order diffracted light, S overlapping position, θ1 first angle, θ2 second angle.

Claims

1. A plurality of laser light sources arranged side by side on the same plane and having one or more light emitting points for emitting a laser beam, an optical element for collimating the laser beam emitted from each of the plurality of laser light sources, a transmission diffraction grating that superimposes a part of the laser beam emitted from the optical element coaxially and emits the coaxially superimposed laser beam as transmitted first-order diffracted light, an output coupler that reflects a part of the transmitted first-order diffracted light emitted from the transmission diffraction grating toward the laser light source and emits the remaining part of the transmitted first-order diffracted light emitted from the transmission diffraction grating, comprising the laser beams emitted from each of the plurality of laser light sources overlap at a position away from each laser light source, the transmission diffraction grating is arranged at a polymerization position where the laser beams emitted from each of the plurality of laser light sources overlap, and is arranged parallel to a direction perpendicular to the same plane, a first gap is formed between two adjacent laser light sources among the plurality of laser light sources, and the first gap is located on the optical path of the reflected first-order diffracted light emitted from the transmission diffraction grating, a first angle formed by a virtual straight line connecting the light emitting point closest to the first gap and the polymerization position, which is arranged on one side with the first gap interposed therebetween, and a virtual straight line connecting the light emitting point closest to the first gap and the polymerization position, which is arranged on the other side with the first gap interposed therebetween, is 0.15 degrees or more. A laser device characterized by this.

2. The laser device according to claim 1, wherein the first angle is 1.0 degree or less.

3. The laser device according to claim 1 or 2, wherein the laser light source is a semiconductor laser array element having a plurality of light emitting points.

4. Further provided with an output monitor member disposed in the first gap for measuring the output fluctuation of the reflected first-order diffracted light. The laser device according to claim 1 or 2, wherein the output monitor member has an incident surface on which the reflected first-order diffracted light is incident.

5. The laser device according to claim 4, further comprising a shielding member installed on the output monitor member and surrounding the periphery of the incident surface.

6. The laser device according to claim 4, further comprising an object-side telecentric lens installed on the incident surface of the output monitor member and transmitting only the reflected first-order diffracted light incident perpendicularly to the incident surface.

7. The laser device according to claim 4, wherein the output monitor member is a photodiode.

8. The laser device according to claim 4, further comprising a light attenuation optical element installed between the incident surface of the output monitor member and the transmissive diffraction grating for attenuating the light intensity of the reflected first-order diffracted light incident on the output monitor member.

9. The laser device according to claim 1 or 2, further comprising a damper disposed in the first gap for absorbing the reflected first-order diffracted light.

10. The optical element is A plurality of first fast-axis collimating lenses provided for each of the plurality of laser light sources for collimating the laser beams emitted from each of the plurality of laser light sources in the fast-axis direction, A plurality of slow-axis collimating lenses provided for each of the plurality of laser light sources for collimating the laser beams emitted from each of the plurality of first fast-axis collimating lenses in the slow-axis direction, A second fast-axis collimating lens for collimating the laser beams emitted from each of the plurality of slow-axis collimating lenses in the fast-axis direction, and has A mirror is further provided between the slow-axis collimating lens and the second fast-axis collimating lens, and reflects the laser beam emitted from the slow-axis collimating lens toward the second fast-axis collimating lens. The mirror is divided into two parts. The laser device according to claim 1 or 2, characterized in that a second gap is formed between two adjacent mirrors and is located on the optical path of the reflected first-order diffracted light.

11. The optical element includes a plurality of first fast-axis collimating lenses provided for each of the plurality of laser light sources and collimating the laser beam emitted from each of the plurality of laser light sources in the fast-axis direction, a plurality of slow-axis collimating lenses provided for each of the plurality of laser light sources and collimating the laser beam emitted from each of the plurality of first fast-axis collimating lenses in the slow-axis direction, a second fast-axis collimating lens that collimates the laser beam emitted from each of the plurality of slow-axis collimating lenses in the fast-axis direction, and The laser device according to claim 1 or 2, further comprising a beam rotation element disposed between the first fast-axis collimating lens and the slow-axis collimating lens and rotating the laser beam 90 degrees around the optical axis of the laser beam.

12. The diffraction angle of the transmitted first-order diffracted light emitted from the transmission type diffraction grating is 60 degrees or more, and the laser device according to claim 1 or 2 is characterized in that.

13. A second angle formed by a virtual straight line connecting the light emitting point farthest from the first gap and the polymerization position and disposed on one side across the first gap and a virtual straight line connecting the light emitting point farthest from the first gap and the polymerization position and disposed on the other side across the first gap is 5 degrees or more, and the laser device according to claim 1 or 2 is characterized in that.

14. The laser device according to claim 1 or 2, and a propagation member that propagates the laser beam emitted from the laser device, and a processing head that condenses the laser beam propagated from the propagation member and irradiates the workpiece therewith, characterized by comprising.

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