JP2023015423A - Laser processing device - Google Patents

Abstract

To reduce a transmission loss in each laser beam in a laser processing device for transmitting laser beams with different wavelengths by an optical fiber.SOLUTION: A laser processing device 100 includes: first and second laser oscillators 1 and 2 for emitting first and second laser beams LB1 and LB2 with different wavelengths; optical path changing means 30 for changing respective optical paths of the first and second laser beams LB1 and LB2 so that they travel in different directions; an optical fiber 60 for guiding the first and second laser beams LB1 and LB2; and a laser head 70 configured so as to condense the first and second laser beams LB1 and LB2 at a predetermined position of a workpiece 200. The optical path changing means 30 is configured so as to make the first laser beam LB1 incident on a second core 63 of the optical fiber 60, and make the second laser beam LB2 incident on a first core 61 of the optical fiber 60.SELECTED DRAWING: Figure 3

Description

The present invention relates to a laser processing apparatus, and more particularly to a laser processing apparatus that emits a plurality of laser beams having different wavelengths.

Conventionally, laser processing equipment that performs processing such as welding using laser light has been widely used. A device has been proposed (see Patent Document 1, for example).

JP 2014-079802 A

By the way, in recent years, there has been proposed a technique of performing laser processing by simultaneously irradiating a work with infrared laser light and visible laser light. For example, by simultaneously irradiating a work with near-infrared laser light and green laser light or blue laser light, high-speed laser processing can be performed while increasing the laser light absorption rate of the work.

However, optical fibers are generally designed to have minimal or minimal transmission loss when light of a particular wavelength is transmitted. Therefore, when light other than the set wavelength is incident on the optical fiber, its transmission loss increases.

Therefore, when trying to transmit laser beams with significantly different wavelengths, such as infrared laser beam and visible laser beam, through the same core of an optical fiber, the transmission loss of one of the laser beams becomes very large. In particular, when high-output laser light is required, such as in laser processing, if the transmission loss is large, there is a risk that the optical fiber will heat up or break.

The present invention has been made in view of such a point, and its object is to provide a laser processing apparatus that transmits laser beams of different wavelengths through an optical fiber, and that can reduce the transmission loss of each laser beam. to do.

To achieve the above object, a laser processing apparatus according to the present invention includes a first laser oscillator that emits a first laser beam of a first wavelength, a second laser oscillator that emits a second laser beam of a second wavelength, optical path changing means for changing respective optical paths of the first laser light and the second laser light so as to travel in different directions; and the first laser light and the second laser light received from the optical path changing means, respectively and at least an optical fiber for guiding light, and a laser head connected to the optical fiber and configured to focus the first laser beam and the second laser beam on predetermined positions on a workpiece, The optical fiber has at least a first core and a second core, each of which is an optical waveguide and which are spaced apart from each other by a predetermined distance, and the optical path changing means converts the first laser beam into the A second core is configured to allow the second laser light to enter the first core, respectively.

According to the laser processing apparatus of the present invention, the loss of each of the first laser beam and the second laser beam transmitted through the optical fiber can be reduced, and the workpiece can be laser-processed with a desired output.

1 is a schematic configuration diagram of a laser processing apparatus according to Embodiment 1 of the present invention; FIG. It is a schematic diagram which shows the cross-section of an optical fiber. Fig. 2 is a schematic diagram of the internal configuration of the beam combiner/separator; It is an example of output control of the first laser oscillator and the second laser oscillator. FIG. 5 is a schematic diagram of the internal configuration of a beam combiner/separator according to Modification 1; It is a schematic diagram which shows the cross-section of another optical fiber. FIG. 5 is a schematic diagram of the internal configuration of a beam combiner/separator according to Embodiment 2; FIG. 11 is a schematic diagram of the internal configuration of a beam combiner/separator according to Modification 2; FIG. 11 is a schematic diagram of the internal configuration of a beam combiner/separator according to Embodiment 3; FIG. 11 is a schematic diagram of the internal configuration of another beam combiner/separator according to Embodiment 3;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail based on the drawings. The following description of preferred embodiments is merely exemplary in nature and is in no way intended to limit the invention, its applicability or its uses.

(Embodiment 1)
[Configuration of laser processing device]
FIG. 1 shows a schematic configuration diagram of a laser processing apparatus according to this embodiment, and FIG. 2 shows a schematic diagram of a cross-sectional structure of an optical fiber. In the following description, the direction perpendicular to the incident end face 60a of the optical fiber 60 is called the Z direction, and the direction parallel to the incident end face 60a of the optical fiber 60 and orthogonal to the Z direction is called the X direction. , the X direction and the Z direction are called the Y direction. Moreover, FIG. 2 is only a schematic diagram and differs from the actual dimensions of each part of the optical fiber 60 .

As shown in FIG. 1, the laser processing apparatus 100 has at least a first laser oscillator 1, a second laser oscillator 2, a beam combiner/separator 10, an optical fiber 60, and a laser head .

In addition, the laser processing apparatus 100 controls the output of the first laser beam LB1 and the second laser beam LB2 by controlling the power supply for driving the first laser oscillator 1 and the second laser oscillator 2 and the output of the power supply. However, illustration and description of these are omitted for convenience of explanation.

The first laser oscillator 1 emits a first laser beam LB1 having a first wavelength, and the second laser oscillator 2 emits a second laser beam LB2 having a second wavelength. In this embodiment, the first wavelength is shorter than the second wavelength, the first wavelength is about 400 nm to 450 nm, and the second wavelength is about 900 nm to 1100 nm. However, they are not particularly limited to this, and can take different values as appropriate. For example, the first wavelength may be about 500-550 nm. Preferably, the first wavelength ranges from 380 nm to 550 nm, and the second wavelength ranges from 800 nm to 1100 nm.

The first laser oscillator 1 and the second laser oscillator 2 may each be a solid-state laser light source, a gas laser light source, or a fiber laser light source. A semiconductor laser light source that directly uses light emitted from a semiconductor laser may also be used. It may also be a semiconductor laser array comprising a plurality of laser light emitters.

The beam coupler/separator 10 couples the first laser beam LB1 emitted from the first laser oscillator 1 and the second laser beam LB2 emitted from the second laser oscillator 2 so that the optical axes thereof substantially coincide with each other. . The beam combiner/separator 10 also directs the first laser beam LB1 to the second core 63 (see FIG. 2) of the optical fiber 60, and the second laser beam LB2 to the first core 61 (see FIG. 2) of the optical fiber 60. , respectively. The internal configuration of the beam combiner/separator 10 will be detailed later.

In the specification of the present application, "substantially the same" and "substantially match" mean that they are the same or match, including the manufacturing tolerance of each part in the laser processing apparatus 100 and the allowable tolerance of the arrangement of each part. It does not mean that the two to be compared are the same or match in a strict sense.

As shown in FIG. 2, the optical fiber 60 has at least a first core 61 and a second core 63 and a first clad 62 and a second clad 64, each of which is an optical waveguide. The outer peripheral surface is covered with a light shielding film (not shown).

The first core 61 has a circular cross-sectional shape and is arranged at the axial center of the optical fiber 60. The first clad 62 is in contact with the outer peripheral surface of the first core 61 and coaxial with the first core 61. It is arranged and has a ring shape in cross section. The second core 63 is arranged coaxially with the first core 61 in contact with the outer peripheral surface of the first clad 62, and has a ring shape in cross section. The second clad 64 is arranged coaxially with the first core 61 in contact with the outer peripheral surface of the second core 63, and has a ring shape in cross section.

The first core 61 and second core 63 and the first clad 62 and second clad 64 are all made of quartz. However, the refractive index of the first clad 62 is set to be lower than the respective refractive indices of the first core 61 and the second core 63 . Also, the refractive index of the second clad 64 is set to be lower than that of the second core 63 .

The first core 61 has optical characteristics such that the transmission loss of the second laser beam LB2 is minimized or minimized, and the second core 63 has optical characteristics such that the transmission loss of the first laser beam LB1 is minimized or minimized. adjusted. From another point of view, the optical characteristics of the first core 61 are adjusted such that the transmission loss of the second laser beam LB2 is smaller than the transmission loss of the first laser beam LB1. The optical characteristics of the second core 63 are adjusted such that the transmission loss of the first laser beam LB1 is smaller than the transmission loss of the second laser beam LB2. These optical characteristics are adjusted, for example, by appropriately setting the amounts of impurities introduced into the first core 61, the second core 63, the first clad 62, and the second clad 64, respectively. Moreover, it is achieved by appropriately setting the refractive index difference between the first core 61 and the first clad 62 and the refractive index difference between the second core 63 and the first clad 62 and the second clad 64 .

As shown in FIG. 1, the laser head 70 has a second housing 71 and a condensing optical system 80 . The second housing 71 has a second connection port 72 and an emission port 73 , and one end of the optical fiber 60 is connected to the second connection port 72 . After the first laser beam LB1 transmitted to the second core 63 of the optical fiber 60 and the second laser beam LB2 transmitted to the first core 61 of the optical fiber 60 enter the second housing 71, It is transmitted through the condensing optical system 80 and emitted from the exit port 73 toward the workpiece 200 . A protective glass 74 is provided at the exit port 73 to prevent fumes and the like from entering the interior of the laser head 70 .

The condensing optical system 80 is provided inside the second housing 71 and is composed of a collimating lens 81 and a condensing lens 82 .

The collimating lens 81 converts the first laser beam LB1 and the second laser beam LB2 into parallel beams, respectively, and the condenser lens 82 converts the first laser beam LB1 and the second laser beam LB2 transmitted through the collimating lens 81 into workpieces. It is configured to focus on the same 200 positions. In addition, the material of each of the collimating lens 81 and the condenser lens 82 is synthetic quartz, which transmits the first laser beam LB1 and the second laser beam LB2, respectively, and is set so that the loss at the time of transmission is equal to or less than a predetermined value. It is configured.

[Configuration of beam combiner/separator]
FIG. 3 shows a schematic diagram of the internal configuration of the beam combiner/separator. Also, FIG. 4 shows an example of output control of the first laser oscillator and the second laser oscillator. For convenience of explanation, in FIG. is connected to the first connection port 14 . The same applies to FIGS. 5 and 7 to 10 shown below.

As shown in FIG. 3, the beam combiner/separator 10 has a polarization beam combiner 20 and a first axicon lens 40 as an optical path changing means 30 inside the first housing 11 . The first housing 11 has a first window 12 for transmitting the first laser beam LB1 emitted from the first laser oscillator 1 and a second window for transmitting the second laser beam LB2 emitted from the second laser oscillator 2. 13 and a first connection port 14 for connecting with the optical fiber 60 are provided. The first connection port 14 of the first housing 11 and the second connection port 72 of the second housing 71 of the laser head 70 are connected by an optical fiber 60 .

The polarization beam combiner 20 is a plate-shaped optical element, and is configured to transmit the first laser beam LB1 and reflect the second laser beam LB2.

The polarization beam combiner 20 has its surface aligned with the optical axis of the first laser beam LB1 emitted from the first laser oscillator 1 and the optical axis of the second laser beam LB2 emitted from the second laser oscillator 2. , 45 degrees.

The first laser beam LB1 that has passed through the first window 12 and the second laser beam LB2 that has passed through the second window 13 are combined by the polarization beam combiner 20 so that their optical axes substantially coincide.

Note that the polarization beam combiner 20 is configured to reflect the first laser beam LB1 and transmit the second laser beam LB2, so that the first laser beam LB1 and the second laser beam LB2 are separated from each other. They may be combined so that their optical axes substantially coincide.

As shown in FIG. 3, the first axicon lens 40 is arranged between the polarization beam combiner 20 and the incident end face 60a of the optical fiber 60, and is a prism lens having a conical exit side. Light incident on the incident surface of the first axicon lens 40 is emitted as ring-shaped light with a diameter D centered on the optical axis of the incident light. The diameter D is represented by the following formula (1).

D=2Ltan((n−1)α) (1)

here,
L: Distance from the vertex of the first axicon lens 40 to the imaging plane n: Refractive index of the first axicon lens 40 is the angle formed by

As is clear from equation (1), when tan((n−1)α) is in the range of 0 to 1, the diameter D increases as the refractive index n increases.

On the other hand, the first axicon lens 40 is made of synthetic quartz, like the collimator lens 81 and the condenser lens 82 described above. In general, the refractive index of synthetic quartz tends to increase as the wavelength shortens.

Therefore, the short-wavelength first laser beam LB1 is converted into ring-shaped light having a larger diameter than the long-wavelength second laser beam LB2 after passing through the first axicon lens 40 . That is, the optical paths of the first laser beam LB1 and the second laser beam LB2 are changed so that they travel in different directions after passing through the first axicon lens 40 .

Also, the first laser beam LB1 and the second laser beam LB2 that have passed through the first axicon lens 40 are imaged on the incident end face 60a of the optical fiber 60 . At this time, the short-wavelength first laser beam LB1 passes through the first axicon lens 40, and is incident on the second core 63 positioned on the outer peripheral side of the first core 61 and the second core 63. . Further, the second laser beam LB2 having a long wavelength is transmitted through the first axicon lens 40, and reaches the inner peripheral side of the optical fiber 60, in this case, the axial center of the first core 61 and the second core 63. It is incident on the positioned first core 61 .

Also, the beam coupler/separator 10 is configured to be movable in any of the XYZ directions. Specifically, the beam combiner/separator 10 further includes a drive mechanism 31 coupled to the first axicon lens 40 and capable of moving the first axicon lens 40 in any of the XYZ directions.

Using this driving mechanism 31, the incident positions of the first laser beam LB1 and the second laser beam LB2 with respect to the incident end surface 60a of the optical fiber 60 are adjusted. For example, the first laser beam LB1 and the second laser beam LB2 are incident on the first axicon lens 40 at the initial position at a lower output than that used in actual processing, and the first laser beam emitted from the laser head 70 The respective outputs of the light LB1 and the second laser light LB2 are measured. The drive mechanism 31 moves the first axicon lens 40 to determine the position of the first axicon lens 40 where the outputs of the first laser beam LB1 and the second laser beam LB2 are maximized. After that, the first axicon lens 40 is held and fixed at that position.

Also, in the present embodiment, as shown in FIG. 4, does the period for emitting the first laser beam LB1 and the period for emitting the second laser beam LB2 completely overlap ((a) in FIG. 4)? Alternatively, the first laser oscillator 1 and the second laser oscillator 2 are controlled so that they partially overlap (FIG. 4(b)).

That is, the workpiece 200 is laser-processed by simultaneously irradiating the same position of the workpiece 200 with the first laser beam LB1 and the second laser beam LB2.

[Effects, etc.]
As described above, the laser processing apparatus 100 according to the present embodiment includes the first laser oscillator 1 that emits the first laser beam LB1 of the first wavelength and the second laser oscillator 1 that emits the second laser beam LB2 of the second wavelength. It has a laser oscillator 2 and a first axicon lens 40 as an optical path changing means 30 for changing the optical paths of the first laser beam LB1 and the second laser beam LB2 so as to travel in different directions. Also, the first wavelength is shorter than the second wavelength.

In addition, the laser processing apparatus 100 includes an optical fiber 60 that guides the first laser beam LB1 and the second laser beam LB2 received from the first axicon lens 40, and the optical fiber 60 that is connected to the first laser beam LB1. and a laser head 70 configured to converge the second laser beam LB2 on a predetermined position of the workpiece 200, respectively.

The optical fiber 60 has a first core 61 as an axial center, and a second core 63, which is ring-shaped in cross section, is coaxial with the first core 61 and spaced from the outer circumference of the first core 61 at a predetermined interval. is provided. The first core 61 and the second core 63 are optical waveguides, respectively.

The first axicon lens 40 is configured to cause the first laser beam LB1 to enter the second core 63 and the second laser beam LB2 to enter the first core 61, respectively.

By configuring the laser processing apparatus 100 in this way, the first laser beam LB1 and the second laser beam LB2 having different wavelengths can be transmitted from the second core 63, which is a different optical waveguide provided in the optical fiber 60, to the first laser beam LB2. The laser head 70 can irradiate the work 200 by guiding the light to the cores 61 respectively.

As described above, when laser beams of different wavelengths are guided through one core of the optical fiber 60, the optical characteristics of the core are defined so that the transmission loss of light of one wavelength is minimized or minimized. If so, the transmission loss of the light of the other wavelength will increase. In particular, when the cable length of the optical fiber 60 becomes long, this tendency becomes remarkable. In a case where a high-power laser beam is required, such as in laser processing, if the transmission loss is large, there is a risk that the optical fiber 60 will heat up or break.

On the other hand, according to the present embodiment, the first laser beam LB1 and the second laser beam LB2 are guided to the second core 63 and the first core 61 of the optical fiber 60, respectively. By appropriately setting the optical characteristics of the core 63, the loss of each of the first laser beam LB1 and the second laser beam LB2 transmitted to the optical fiber 60 can be reduced, and the workpiece 200 is laser-processed at a desired output. be able to.

The first core 61 has optical characteristics such that the transmission loss of the second laser beam LB2 is minimized or minimized, and the second core 63 has optical characteristics such that the transmission loss of the first laser beam LB1 is minimized or minimized. is adjusted. From another point of view, the first core 61 has the transmission loss of the first laser beam LB1 so that the transmission loss of the second laser beam LB2 is smaller than the transmission loss of the first laser beam LB1. are smaller than the transmission loss LB2 of the second laser light.

By doing so, the loss of each of the first laser beam LB1 and the second laser beam LB2 transmitted through the optical fiber 60 can be appropriately reduced.

Inside the laser head 70, a condensing optical system 80 is provided for condensing the first laser beam LB1 and the second laser beam LB2 emitted from the optical fiber 60 at the same condensing position.

By configuring the laser head 70 in this way, the first laser beam LB1 and the second laser beam LB2, each of which has a reduced transmission loss, can be focused on the same position on the workpiece 200. Desired laser processing can be performed.

The first axicon lens 40 is configured to be movable in the XY plane, which is a direction substantially parallel to the incident end face 60a of the optical fiber 60, and in the Z direction, which is a direction perpendicular to the incident end face 60a. Specifically, the beam combiner/separator 10 further includes a drive mechanism 31 coupled to the first axicon lens 40 and capable of moving the first axicon lens 40 in any of the XYZ directions.

By doing so, the second laser beam LB2 and the first laser beam LB1 can be reliably made incident on the first core 61 and the second core 63, respectively. As a result, the loss of each of the first laser beam LB1 and the second laser beam LB2 can be reliably reduced, and the laser processing of the workpiece 200 can be performed with a desired output.

<Modification 1>
FIG. 5 shows a schematic diagram of the internal configuration of the beam combiner/separator according to this modification. In addition, in FIG. 5 and subsequent drawings, portions similar to those of the first embodiment are assigned the same reference numerals, and detailed description thereof will be omitted. Although not shown, in the laser processing apparatus 100 according to this modification, the components other than the beam combiner/separator 10 are the same as those shown in FIG.

The beam combiner/separator 10 shown in FIG. 5 differs from the beam combiner/separator 10 shown in FIG. 3 in that the optical path changing means 30 is the first prism 41 . The first prism 41 is made of synthetic quartz.

As shown in this modified example, the optical path changing means 30 may be a prism. When the first laser beam LB1 and the second laser beam LB2 respectively enter the first prism 41, the optical path of the second laser beam with the longer wavelength is not bent significantly. On the other hand, the optical path of the short-wavelength first laser beam LB1 is bent more than the optical path of the second laser beam LB2. By appropriately setting the positional relationship between the first prism 41 and the incident end surface 60a of the optical fiber 60, the first laser beam LB1 and the second laser beam LB2 are caused to enter the second core 63, respectively. be able to.

Specifically, the short-wavelength first laser beam LB1 passes through the first prism 41 and is incident on the second core 63 positioned on the outer peripheral side of the first core 61 and the second core 63. be. In addition, the second laser beam LB2 having a long wavelength passes through the first prism 41, and is located on the inner peripheral side of the optical fiber 60, in this case, at the axial center of the first core 61 and the second core 63. It is incident on the first core 61 .

As a result, the same effect as that of the configuration shown in the first embodiment can be obtained. That is, the loss of each of the first laser beam LB1 and the second laser beam LB2 guided by the optical fiber 60 can be reduced, and the workpiece 200 can be laser-processed with a desired output.

When a prism is used as the optical path changing means 30, the structure of the optical fiber 60 may be different from that shown in FIG. 2. As shown in FIG. The core 631 may be arranged with a gap therebetween with the first clad 621 interposed therebetween. Moreover, FIG. 6 is only a schematic diagram and differs from the actual dimensions of each part of the optical fiber 60 .

As in the first embodiment, the first core 61 has a minimum or minimum transmission loss of the second laser beam LB2, and the second core 63 has a transmission loss of the first laser beam LB1. Each optical characteristic is adjusted to be the minimum or minimum. From another point of view, the optical characteristics of the first core 61 are adjusted such that the transmission loss of the second laser beam LB2 is smaller than the transmission loss of the first laser beam LB1. The optical characteristics of the second core 63 are adjusted such that the transmission loss of the first laser beam LB1 is smaller than the transmission loss LB2 of the second laser beam.

By doing so, similarly to the first embodiment, the loss of each of the first laser beam LB1 and the second laser beam LB2 guided by the optical fiber 60 can be greatly reduced, and the workpiece can be produced at a desired output. 200 laser processes can be performed.

When the optical fiber 60 shown in FIG. 6 is used, an optical component (not shown) is arranged inside the laser head 70 so that the optical axis of the first laser beam LB1 and the optical axis of the second laser beam LB2 are substantially aligned. preferably. By doing so, the first laser beam LB<b>1 and the second laser beam LB<b>2 can be focused on the same position on the workpiece 200 .

(Embodiment 2)
FIG. 7 shows a schematic diagram of the internal configuration of the beam combiner/separator according to this embodiment. Although not shown, in the laser processing apparatus 100 according to this embodiment, the components other than the beam combiner/separator 10 are the same as those shown in FIG.

The beam combiner/separator 10 shown in FIG. 7 has a second axicon lens (second component) 50 arranged between a first axicon lens (first component) 40 and an incident end surface 60 a of an optical fiber 60 . 3 in that it differs from the beam combiner/separator 10 shown in FIG. As will be shown later, the second axicon lens 50 is also the optical path changing means 30 . Also, the first axicon lens 40 and the second axicon lens 50 are made of synthetic quartz. Also, the second axicon lens 50 has the same shape as the first axicon lens 40 or a similar shape.

As shown in FIG. 7, the second axicon lens 50 is spaced apart from the first axicon lens 40 by a predetermined distance in the Z direction, and the conical portions of the first axicon lens 40 face each other. are placed.

By arranging the first axicon lens 40 and the second axicon lens 50 in this manner, the optical paths of the first laser beam LB1 and the second laser beam LB2 can be changed as follows.

First, as described above, by passing through the first axicon lens 40, the optical paths of the first laser beam LB1 and the second laser beam LB2 are changed so that they travel in different directions.

When the first laser beam LB1 transmitted through the first axicon lens 40 is incident on the second axicon lens 50, it is refracted by the second axicon lens 50 again. At this time, the second axicon lens 50 has the same shape as the first axicon lens 40 or a similar shape. Also, the first axicon lens 40 and the second axicon lens 50 have the arrangement relationship described above. Therefore, the refracted light travels in a direction parallel to the original traveling direction. That is, in this case, the optical path of the first laser beam LB1 is changed so as to travel in a direction perpendicular to the incident end face 60a of the optical fiber 60. FIG.

Similarly, the second laser beam LB2 is also refracted again by the second axicon lens 50 and travels in a direction parallel to the original traveling direction. That is, the optical path of the second laser beam LB2 is changed so that it travels in a direction perpendicular to the incident end face 60a of the optical fiber 60. FIG.

According to this embodiment, the same effects as those of the configuration shown in the first embodiment can be obtained. That is, the loss of each of the first laser beam LB1 and the second laser beam LB2 guided by the optical fiber 60 can be greatly reduced, and the workpiece 200 can be laser-processed with a desired output.

Also, the first laser beam LB1 and the second laser beam LB2 can be made incident from a direction perpendicular to the incident end surface 60a of the optical fiber 60. As shown in FIG. As a result, the beam quality of the first laser beam LB1 and the second laser beam LB2 emitted from the optical fiber 60, and the beam quality of the first laser beam LB1 and the second laser beam LB2 irradiated to the workpiece 200 are improved. be able to.

As is conventionally known, the incident angle of the laser light on the incident end face 60a of the optical fiber 60 corresponds to the emission angle of the laser light from the outgoing end face of the optical fiber 60. FIG. Therefore, if the incident angle deviates significantly from 90 degrees, the laser light emitted from the optical fiber 60 will also spread greatly according to the angle.

As shown in FIG. 1, the laser head 70 is provided with a condensing optical system 80, and the first laser beam LB1 and the second laser beam LB2 are condensed to form a spot on the surface of the workpiece 200. FIG. However, if the laser light emitted from the optical fiber 60 is greatly spread and enters the condensing optical system 80, the laser light cannot be sufficiently condensed, resulting in deterioration of beam quality. That is, the spot diameter on the surface of the workpiece 200 becomes large. Therefore, there is a possibility that the workpiece 200 cannot be processed to the desired dimensions.

On the other hand, according to the present embodiment, the first laser beam LB1 and the second laser beam LB2 are caused to be incident on the workpiece 200 from a direction perpendicular to the incident end surface 60a of the optical fiber 60. The beam quality of the second laser beam LB2 can be improved. As a result, the workpiece 200 can be processed with desired dimensions.

<Modification 2>
FIG. 8 shows a schematic diagram of the internal configuration of the beam combiner/separator according to this modification. Although not shown, in the laser processing apparatus 100 according to this modification, the components other than the beam combiner/separator 10 are the same as those shown in FIG.

The beam combiner/separator 10 shown in FIG. 8 is provided with a second prism 51 in addition to the first prism 41 as the optical path changing means 30. 10 different. The first prism (first component) 41 and the second prism (second component) 51 are the first axicon lens (first component) 40 and the second axicon lens (second component) shown in the second embodiment, respectively. It corresponds to 50. Both the first prism 41 and the second prism 51 are made of synthetic quartz.

By passing through the first prism 41, the optical paths of the first laser beam LB1 and the second laser beam LB2 are changed so that they travel in different directions.

When the first laser beam LB1 that passes through the first prism 41 and travels in a different direction from the second laser beam LB2 enters the second prism 51, it is refracted by the second prism 51 again. The refracted first laser beam LB1 travels in a direction parallel to the original traveling direction. That is, in this case, the optical path of the first laser beam LB1 is changed so as to travel in a direction perpendicular to the incident end face 60a of the optical fiber 60. FIG.

Similarly, the second laser beam LB2 is refracted again by the second prism 51 and travels in a direction parallel to the original traveling direction. That is, the optical path of the second laser beam LB2 is changed so that it travels in a direction perpendicular to the incident end face 60a of the optical fiber 60. FIG.

According to this modified example, it is possible to obtain the same effect as the configuration shown in the second embodiment. That is, the loss of each of the first laser beam LB1 and the second laser beam LB2 guided by the optical fiber 60 can be greatly reduced, and the workpiece 200 can be laser-processed with a desired output. Moreover, by making the first laser beam LB1 and the second laser beam LB2 enter from a direction perpendicular to the incident end surface 60a of the optical fiber 60, the beams of the first laser beam LB1 and the second laser beam LB2 irradiated to the workpiece 200 Quality can be improved. As a result, the workpiece 200 can be processed with desired dimensions.

In addition, in the laser processing apparatus 100 of this modified example, it is possible to use not only the optical fiber 60 having the structure shown in FIG. 2 but also the optical fiber 60 having the structure shown in FIG. Needless to say.

(Embodiment 3)
FIG. 9 shows a schematic diagram of the internal configuration of the beam combiner/separator according to this embodiment, and FIG. 10 shows a schematic diagram of the internal configuration of another beam combiner/separator. Although not shown, in the laser processing apparatus 100 according to this embodiment, the components other than the beam combiner/separator 10 are the same as those shown in FIG.

The beam combiner/separator 10 shown in FIG. 9 differs from the beam combiner/separator 10 shown in FIGS. 3 and 5 in that the optical path changing means 30 is the first diffraction grating 42 . The beam combiner/separator 10 shown in FIG. 10 has a first diffraction grating (first component) 42 and a second diffraction grating (second component) 52 as the optical path changing means 30, which is different from that shown in FIGS. differs from the beam combiner/separator 10 shown in FIG. In addition, in this embodiment, the first diffraction grating 42 and the second diffraction grating 52 are respectively transmissive diffraction gratings.

Further, the optical fiber 60 used in the laser processing apparatus 100 of this embodiment differs from the optical fiber 60 shown in FIG. 2 in the following points.

First, the first core 61 has optical characteristics such that the transmission loss of the first laser beam LB1 is minimized or minimized, and the second core 63 has optical characteristics such that the transmission loss of the second laser beam LB2 is minimized or minimized. adjusted. From another point of view, the optical characteristics of the first core 61 are adjusted such that the transmission loss of the first laser beam LB1 is smaller than the transmission loss of the second laser beam LB2. The optical characteristics of the second core 63 are adjusted such that the transmission loss of the second laser beam LB2 is smaller than the transmission loss of the first laser beam LB1.

As shown in FIG. 9, when the first laser beam LB1 and the second laser beam LB2 each pass through the first diffraction grating 42, the second laser beam LB2 with the longer wavelength is transmitted through the first laser beam LB1 with the shorter wavelength. is diffracted at angles greater than Therefore, the second laser beam LB2 is incident on the second core 63 positioned on the outer peripheral side of the first core 61 and the second core 63 . Also, the first laser beam LB1 is incident on the first core 61 positioned on the inner peripheral side of the optical fiber 60, in this case, at the axial center, out of the first core 61 and the second core 63. As shown in FIG.

Further, as shown in FIG. 10, a second diffraction grating 52 is provided after the first diffraction grating 42, and the angle of the main surface of the second diffraction grating 52 with respect to the main surface of the first diffraction grating 42 and the angle of the first diffraction grating 52 By appropriately setting the respective diffraction pitches of the grating 42 and the second diffraction grating 52, the first laser beam LB1 and the second laser beam LB2 can be made incident from a direction perpendicular to the incident end face 60a of the optical fiber 60. .

According to the configuration shown in FIG. 9, it is possible to achieve the same effect as the configuration shown in the first embodiment and the first modification. That is, the loss of each of the first laser beam LB1 and the second laser beam LB2 guided by the optical fiber 60 can be greatly reduced, and the workpiece 200 can be laser-processed with a desired output.

Moreover, according to the structure shown in FIG. 10, in addition to the above, the same effects as those of the structures shown in the second embodiment and the modified example 2 can be obtained. In other words, the beams of the first laser beam LB1 and the second laser beam LB2 that irradiate the workpiece 200 are caused by making the first laser beam LB1 and the second laser beam LB2 enter from the direction perpendicular to the incident end surface 60a of the optical fiber 60. quality can be improved. As a result, the workpiece 200 can be processed with desired dimensions.

In addition, in the laser processing apparatus 100 of the present embodiment, not only the optical fiber 60 having the structure shown in FIG. 2 but also the optical fiber 60 having the structure similar to that shown in FIG. It goes without saying that it is possible. However, the first diffraction grating 42 and the second diffraction grating 52 and the first core 61 and the second laser beam LB2 are arranged so that the first laser beam LB1 is incident on the first core 61 and the second laser beam LB2 is incident on the second core 63, respectively. It is necessary to set the layout relationship with the 2 cores 63 .

Further, in this embodiment, since the first diffraction grating 42 and the second diffraction grating 52 are used as the optical path changing means 30 , part of the laser light is not transmitted to the optical fiber 60 . Therefore, in order to increase the light amount of the laser light of the diffraction order used for transmission to the optical fiber 60, it is preferable to increase the diffraction efficiency in the order as much as possible. For example, when +1st-order diffracted light is used, the diffraction efficiency may be increased by adjusting the depth of the diffraction grooves of the first diffraction grating 42 and the second diffraction grating 52 .

(Other embodiments)
In the specification of the present application, the beam combiner/separator 10 in which the polarization beam combiner 20 and the optical path changing means 30 are arranged inside the same first housing 11 is shown as an example. It may be placed on the body. That is, the beam combiner and the beam separator may be provided separately. Other optical components may also be arranged in the beam combiner/separator 10 .

Even when the beam combiner and the beam separator are provided separately, the optical axis of the first laser beam LB1 and the optical axis of the second laser beam LB2 that enter the beam separator are substantially aligned. is preferred.

Further, in the laser processing apparatus 100 shown in each embodiment and each modification, when the difference between the first wavelength and the second wavelength is large, for example, the first wavelength is in the range of 380 nm or more and 550 nm or less, and the second wavelength is in the range of 380 nm or more and 550 nm or less. It is particularly useful when the wavelength is in the range of 800 nm or more and 1100 nm or less. The laser processing of the workpiece 200 can be performed with the output of .

For example, a copper material has a low light absorptivity in the wavelength region of the second wavelength. Light absorption is enhanced, and the temperature of the portion irradiated with the first laser beam LB1 and the second laser beam LB2 rises in a short period of time. In addition, when the temperature of the copper material approaches the melting point, the optical absorption rate in the wavelength region of the second wavelength sharply increases. Available.

Moreover, by setting the wavelength regions of the first wavelength and the second wavelength as described above, it is possible to suppress the generation of spatters and debris during laser processing of the workpiece 200 . Thereby, the machining quality of the work 200 can be improved.

Note that the laser head 70 may be held by a robot arm (not shown). By doing so, the laser head 70 can be brought to an appropriate position even for the workpiece 200 having a complicated shape, and the desired laser processing can be performed on the workpiece 200 .

INDUSTRIAL APPLICABILITY The laser processing apparatus of the present invention can irradiate a workpiece with laser beams having different wavelengths while reducing transmission loss in an optical fiber, and is therefore useful for performing laser processing that requires high-power laser beams.

1 First Laser Oscillator 2 Second Laser Oscillator 10 Beam Combiner/Separator 11 First Housing 12 First Window 13 Second Window 14 First Connection Port 20 Polarization Beam Combiner 30 Optical Path Changing Means 31 Drive Mechanism 40 First Axicon Lens (Part 1)
41 first prism (first part)
42 first diffraction grating (first part)
50 second axicon lens (second part)
51 second prism (second part)
52 second diffraction grating (second component)
60 Optical fiber 60a Incident end face 61, 611 First core 62, 621 First clad 63, 631 Second core 64 Second clad 70 Laser head 71 Second housing 72 Second connection port 73 Output port 74 Protective glass 80 Focusing Optical system 81 Collimating lens 82 Condensing lens 100 Laser processing device 200 Work

Claims (17)

a first laser oscillator that emits a first laser beam of a first wavelength;
a second laser oscillator that emits a second laser beam of a second wavelength;
optical path changing means for changing respective optical paths of the first laser beam and the second laser beam so as to travel in different directions;
an optical fiber that guides each of the first laser beam and the second laser beam received from the optical path changing means;
at least a laser head connected to the optical fiber and configured to focus the first laser beam and the second laser beam on predetermined positions of a workpiece;
The optical fiber has at least a first core and a second core, each of which is an optical waveguide and which are spaced apart from each other by a predetermined distance,
The laser processing apparatus, wherein the optical path changing means is configured to cause the first laser beam to enter the second core and the second laser beam to enter the first core, respectively. In the laser processing apparatus according to claim 1,
The laser processing apparatus, wherein the optical path changing means is an axicon lens. In the laser processing apparatus according to claim 1,
The laser processing apparatus, wherein the optical path changing means is a prism. In the laser processing apparatus according to claim 1 or 2,
The optical fiber has the first core as an axial center, and the second core, which is ring-shaped in a cross-sectional view, is coaxial with the first core and spaced from the outer circumference of the first core at a predetermined distance. A laser processing device, characterized by comprising: In the laser processing apparatus according to claim 1,
The optical path changing means is
a first component that changes optical paths such that the first laser beam and the second laser beam travel in different directions;
and a second component which is provided after the first component and changes the respective optical paths so that the first laser light and the second laser light travel in a direction perpendicular to the incident end surface of the optical fiber. A laser processing device characterized by comprising: In the laser processing apparatus according to claim 5,
A laser processing apparatus, wherein the first component and the second component are axicon lenses, respectively. In the laser processing apparatus according to claim 5,
A laser processing apparatus, wherein the first component and the second component are prisms, respectively. In the laser processing apparatus according to claim 5 or 6,
The optical fiber has the first core as an axial center, and the second core, which is ring-shaped in a cross-sectional view, is coaxial with the first core and spaced from the outer circumference of the first core at a predetermined distance. A laser processing device, characterized by comprising: In the laser processing apparatus according to any one of claims 1 to 8,
The first core has a minimum or minimum transmission loss of the second laser light,
The second core has a minimum or minimum transmission loss of the first laser light,
A laser processing apparatus, wherein optical characteristics of each are adjusted. a first laser oscillator that emits a first laser beam of a first wavelength;
a second laser oscillator that emits a second laser beam of a second wavelength;
optical path changing means for changing respective optical paths of the first laser beam and the second laser beam so as to travel in different directions;
an optical fiber that guides each of the first laser beam and the second laser beam received from the optical path changing means;
at least a laser head connected to the optical fiber and configured to focus the first laser beam and the second laser beam on predetermined positions of a workpiece;
The optical fiber has at least a first core and a second core, each of which is an optical waveguide and which are spaced apart from each other by a predetermined distance,
The laser processing apparatus, wherein the optical path changing means is configured to cause the first laser beam to enter the first core and the second laser beam to enter the second core, respectively. In the laser processing apparatus according to claim 10,
The laser processing apparatus, wherein the optical path changing means is a diffraction grating. In the laser processing apparatus according to claim 10 or 11,
The optical path changing means is
a first component that changes optical paths such that the first laser beam and the second laser beam travel in different directions;
and a second component which is provided after the first component and changes the respective optical paths so that the first laser light and the second laser light travel in a direction perpendicular to the incident end surface of the optical fiber. A laser processing device characterized by comprising: In the laser processing apparatus according to claim 12,
A laser processing apparatus, wherein the first component and the second component are diffraction gratings, respectively. In the laser processing apparatus according to any one of claims 10 to 13,
The first core has a minimum or minimum transmission loss of the first laser light,
The second core has a minimum or minimum transmission loss of the second laser light,
A laser processing apparatus, wherein optical characteristics of each are adjusted. In the laser processing apparatus according to any one of claims 1 to 14,
The laser processing apparatus, wherein the optical path changing means is movable in a direction substantially parallel to and perpendicular to the incident end face of the optical fiber. In the laser processing apparatus according to any one of claims 1 to 15,
A focusing optical system is provided inside the laser head for focusing the first laser beam and the second laser beam emitted from the optical fiber at the same focusing position. laser processing equipment. In the laser processing apparatus according to any one of claims 1 to 16,
the first wavelength is in the range of 380 nm or more and 550 nm or less;
The laser processing apparatus, wherein the second wavelength is in the range of 800 nm or more and 1100 nm or less.

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