Laser processing device

Abstract

To provide a laser processor which overlaps a plurality of laser beams with wavelengths different from each other, and can satisfactorily irradiate any place on an object to be processed with the same via a galvano-scanner.SOLUTION: A laser processor 0 comprises: a combiner part 3 which overlaps a plurality of laser beams L1, L2 with wavelengths different from each other on a same optical axis; a focus shifter part 4 which adjusts a focal distance of the laser beams L1, L2 overlapped by the combiner part 3; and a galvano-scanner part 5 which is located on a downstream side of the focus shifter part 4, and displaces a direction of the optical axis of the laser beams L1, L2 directed to the object to be processed. The laser processor synchronizes adjustment of the focal distance by the focus shifter part 4 and displacement of the direction of the optical axis by the galvano-scanner part 5.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a laser processing apparatus that irradiates an arbitrary portion of a workpiece (or a workpiece to be processed) with a laser beam to perform a desired process on the workpiece.

Background Art

[0002] As a laser processing apparatus that irradiates an arbitrary portion on a workpiece with a laser beam, a device that displaces the optical axis of a laser beam using a galvanometer scanner is known. A galvanometer scanner includes a mirror that reflects a laser beam and a servo motor or a stepping motor that rotates the angle of the mirror at high speed and with high precision.

[0003] When the direction of the mirror of the galvanometer scanner, and thus the direction of the laser optical axis, is displaced, the angle at which the laser optical axis intersects the workpiece changes, and at the same time, the optical path length from the mirror to the workpiece expands or contracts. Therefore, generally, an fθ lens or a telecentric lens is provided between the mirror of the galvanometer scanner and the workpiece so that the focus of the laser beam passing through the lens is always appropriately focused on the upper surface of the workpiece (for the above, see, for example, the following patent documents).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the welding process of copper plates, copper terminals, etc., it may be desired to irradiate an arbitrary location on the workpiece by superimposing two or more types of laser light having different wavelengths. Typically, after superimposing blue laser light and infrared laser light, the welding location on the workpiece is irradiated. Copper absorbs blue light well, but since the output of existing blue laser light sources is not necessarily sufficiently large, a high-power infrared laser light source is used in combination.

[0006] As described above, galvanoscanners are usually used together with fθ lenses. However, in the case of lenses that transmit laser light, chromatic aberration inevitably occurs as an inevitable physical law (due to the refractive index of light depending on the wavelength of that light). Therefore, when attempting to irradiate a workpiece with a superimposed plurality of laser lights having different wavelengths through an fθ lens, the irradiation position of the laser light of one wavelength and the irradiation position of the other laser light that should be superimposed thereon will shift on the workpiece. Due to this shift, there is a concern that the desired laser treatment or processing result cannot be obtained.

[0007] Therefore, conventionally, a galvanoscanner could not be used, and instead, an XY stage (which supports the workpiece or the laser processing nozzle) was used to relatively move the workpiece with respect to the laser optical axis.

[0008] Although there are also lenses made of glass materials with relatively little chromatic aberration, when laser light is absorbed, a change in refractive index occurs as a thermal lens effect, so it is practically difficult to apply them to kW-class high-power lasers.

[0009] The present invention aims to provide a laser processing apparatus that can superimpose a plurality of laser lights having different wavelengths on each other and suitably irradiate an arbitrary location on a workpiece through a galvanoscanner.

Means for Solving the Problem

[0010] In the present invention, a combiner unit that superimposes a plurality of laser lights having different wavelengths on the same optical axis, and the combiner unit is arranged on the downstream side of the optical path and the combiner unit superimposed byand A laser processing apparatus is configured that includes a focus shifter unit that adjusts the focal length of a laser beam, and a galvanometer scanner unit that is downstream of the focus shifter unit and displaces the direction of the optical axis of the laser beam directed toward a workpiece, and synchronizes the adjustment of the focal length by the focus shifter unit and the displacement of the direction of the optical axis by the galvanometer scanner unit.

[0011] Ideally, there is no lens that allows the laser beam to pass between the galvanometer scanner unit and the workpiece. However, if chromatic aberration (including the thermal lens effect) occurs only to such an extent that the deviation of the irradiation position of each laser beam can be ignored, it does not prevent the interposition of some lens that transmits the laser beam (a plurality of laser beams having different wavelengths superimposed) between the galvanometer scanner unit and the workpiece.

[0012] The focus shifter unit has a lens that adjusts the focal length of the laser beam by moving forward and backward along the optical axis of the laser beam. 。

[0013] The focus shifter unit has, for example, a lens that expands the diameter of the laser beam superimposed by the combiner unit, and a lens that reduces the diameter of the laser beam that has passed through the lens, and expands and contracts the relative distance between the two lenses along the optical axis of the laser beam in synchronization with the displacement of the direction of the optical axis by the galvanometer scanner unit.

[0014] The laser processing apparatus according to the present invention is used, for example, for performing welding by irradiating a workpiece with a laser beam. This laser processing apparatus irradiates the workpiece through, for example, the focus shifter unit and the galvanometer scanner unit with a blue laser beam and an infrared laser beam via the combiner unit. superimposed thereon, and the superimposed laser light Irradiate the workpiece through the focus shifter unit and the galvanometer scanner unit.

Advantages of the Invention

[0015] According to the present invention, it is possible to realize a laser processing apparatus that can superimpose a plurality of laser beams having different wavelengths and suitably irradiate an arbitrary location on a workpiece through a galvanometer scanner.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0017] An embodiment of the present invention will be described with reference to the drawings. The laser processing apparatus 0 of the present embodiment can irradiate an arbitrary position on a workpiece (or a work piece, a workpiece) W with a plurality of laser beams L1, L2 having different wavelengths after superimposing them.

[0018] The laser processing apparatus 0 of the present embodiment shown in FIGS. 1 to 3 includes a laser light source 1, 2 that outputs a plurality of laser beams L1, L2 having different wavelengths, respectively, a combiner section 3 that superimposes the plurality of laser beams L1, L2 supplied from the laser light sources 1, 2 on the same optical axis, a focus shifter section 4 that adjusts the focal length of the laser beams L1, L2 superimposed on the same optical axis downstream of the combiner section 3, and a galvanometer scanner section 5 that displaces the direction of the optical axis of the laser beams L1, L2 heading toward the workpiece W downstream of the focus shifter section 4.

[0019] This laser processing apparatus 0 is mainly assumed to perform laser welding processing by irradiating laser beams L1 and L2 onto a copper plate as the workpiece W or copper contacts on the workpiece W to weld them. This laser processing apparatus 0 is equipped with, for example, a light source 1 that outputs blue laser light L1 with a wavelength of approximately 450 nm and a light source 2 that outputs near-infrared laser light L2 with a wavelength of approximately 1070 nm, and superimposes both laser beams L1 and L2 supplied from these respective light sources 1 and 2 in a combiner unit 3 first.

[0020] As shown in FIG. 1, the combiner unit 3 has, for example, lenses (such as collimation lenses) 31 and 32 that collimate the laser beams L1 and L2 supplied from the light sources 1 and 2 respectively, and mirrors (including beam splitters, half mirrors, combiners, etc.) 33 and 34 necessary to align the optical axes of the respective laser beams L1 and L2 that have passed through the lenses 31 and 32. Of course, the combiner unit 3 may have optical elements, optical fibers, or others other than the above. Also, the wavelengths of the laser beams L1 and L2 supplied from the respective light sources 1 and 2 are not particularly limited. Instead of the blue laser beam L1, a green laser beam may be employed, or a near-infrared laser beam with a wavelength different from that of the laser beam L2 (for example, approximately 808 nm) may be employed. In addition, in the combiner unit 3, it is also possible to superimpose three or more types of laser beams with different wavelengths.

[0021] As shown in FIG. 2, the focus shifter unit 4 has a lens (concave lens, especially a double concave lens, etc.) 41 that expands the diameters of the laser beams L1 and L2 superimposed in the combiner unit 3, and lenses (a plurality of convex lenses, especially plano-convex lenses that serve as collimation lenses or condenser lenses, etc.) 42 and 43 that reduce the diameters of the laser beams L1 and L2 that have passed through the lens 41. Of course, the focus shifter unit 4 may have optical elements, optical fibers, or others other than the above.

[0022] The focus shifter unit 4 variably adjusts the focal length F of the laser beams L1 and L2 provided by the combiner unit 3. For this purpose, in the example shown in FIG. 2, at least one of the concave lens 41 and the convex lens 42 is supported by a linear motor carriage or other appropriate drive mechanism so that the relative distance D along the axes of the laser beams L1 and L2 between the concave lens 41 and the convex lens 42 can be variably adjusted, and is made movable forward and backward along the optical axis direction. Incidentally, the terminal condenser lens 43 does not have to move forward and backward along the optical axis direction.

[0023] As shown in (A) in FIG. 2, the shorter the distance D between the concave lens 41 and the convex lens 42, the longer the focal length F of the laser beams L1 and L2 that have passed through the lenses 41, 42, and 43 of the focus shifter unit 4. That is, the foci of the laser beams L1 and L2 move away from the lens 43 at the terminal of the focus shifter unit 4.

[0024] Conversely, as shown in (B) in FIG. 2, the longer the distance D between the concave lens 41 and the convex lens 42, the shorter the focal length F of the laser beams L1 and L2 that have passed through the lenses 41, 42, and 43 of the focus shifter unit 4. That is, the foci of the laser beams L1 and L2 approach the lens 43 at the terminal of the focus shifter unit 4.

[0025] Note that chromatic aberration may also occur in the lenses 41, 42, and 43. Therefore, in practice, the positions of the lens 31 and / or the lens 32 that allow the laser beams L1 and L2 output from the respective laser light sources 1 and 2 to pass through are adjusted so that the foci of the overlapping laser beam L1 and the laser beam L2 are aligned.

[0026] As shown in FIGS. 1 and 3, the galvanometer scanner unit 5 is a known one that rotates mirrors 53 and 54, which reflect the laser beams L1 and L2 provided by the focus shifter unit 4, via a drive mechanism of servo motors, stepping motors, etc. 51 and 52. In short, the galvanometer scanner unit 5 can displace the directions of the optical axes of the laser beams L1 and L2 reflected by the mirrors 53 and 54. The galvanometer scanner unit 5 in the present embodiment includes an X-axis galvanometer scanner 51 and 53 that change the optical axes of the laser beams L1 and L2 toward the workpiece W along the X-axis direction on the workpiece W, and a Y-axis galvanometer scanner 52 and 54 that change the optical axes of the same laser beams L1 and L2 along the Y-axis direction on the workpiece W. The laser beams L1 and L2 are scanned in the XY two-dimensional direction with respect to the workpiece W, so that the irradiation positions of the laser beams L1 and L2 on the workpiece W can be controlled two-dimensionally.

[0027] As a feature of the laser processing apparatus 0 of the present embodiment, synchronization of the adjustment of the focal length F by the focus shifter unit 4 and the displacement of the direction of the optical axis by the galvanometer scanner unit 5 can be mentioned.

[0028] The closer the angle θ of the optical axes of the laser beams L1 and L2 with respect to the workpiece W via the mirrors 53 and 54 of the galvanometer scanner unit 5 is to being perpendicular, the shorter the optical path length from the mirror 53 to the workpiece W becomes. Therefore, as the angle θ of the laser beams L1 and L2 axes with respect to the workpiece W approaches perpendicular (90°), the focus shifter unit 4 and the galvanometer scanner unit 5 are synchronously controlled so as to shorten the focal length F realized by the focus shifter unit 4.

[0029] Conversely, the more the angle θ of the optical axes of the laser beams L1 and L2 with respect to the workpiece W via the mirrors 53 and 54 of the galvanometer scanner unit 5 is inclined from perpendicular, the longer the optical path length from the mirror 53 to the workpiece W becomes. Therefore, as the angle θ of the laser beams L1 and L2 axes with respect to the workpiece W inclines (moves away from 90°), the focus shifter unit 4 and the galvanometer scanner unit 5 are synchronously controlled so as to increase the focal length F realized by the focus shifter unit 4.

[0030] Through the synchronization control of the lenses 41 and 42 of the focus shifter unit 4 and the mirrors 53 and 54 of the galvanometer scanner unit 5 described above, the laser beams L1 and L2 can be irradiated onto any location on the object W to be processed, and moreover, the foci of the laser beams L1 and L2 can be accurately aligned with the desired processing target surface of the object W to be processed.

[0031] It is desirable that there is no lens (such as an fθ lens) that allows the laser beams L1 and L2 to pass between the mirrors 53 and 54 of the galvanometer scanner unit 5 and the object W to be processed. In this way, the problem of chromatic aberration that occurs when the laser beams L1 and L2 whose optical axis directions are manipulated by the galvanometer scanner unit 5 pass through the lens can be reliably avoided. That is, there is no shift between the position where the laser beam L1 of a certain wavelength hits the object W and the position where the laser beam L2 superimposed thereon hits the object W. Therefore, the desired laser processing or machining results can be obtained.

[0032] However, if chromatic aberration occurs only to such an extent that the shift in the irradiation positions of the laser beams L1 and L2 can be ignored, it does not prevent the intervention of some lens that transmits the laser beams L1 and L2 between the mirrors 53 and 54 of the galvanometer scanner unit 5 and the object W to be processed.

[0033] Note that the present invention is not limited to the embodiments described in detail above. In the above embodiments, the biconcave lens 41, the collimation lens 42, and the condenser lens 43, which are elements of the focus shifter unit 4, were all located downstream of the mirrors 33 and 34, which are elements of the combiner unit 3. However, the arrangement of these optical elements 33, 34, 41, 42, and 43 is not limited to that shown in FIG. 1.

[0034] As shown in FIG. 4 Reference Example In this case, the biconcave lens 41 and the collimation lens 42 are arranged on the optical axes of the laser beam L1 output from the laser light source 1 and the optical axis of the laser beam L2 output from the laser light source 2, respectively. In short, there are two biconcave lenses 41 and two collimation lenses 42.

[0035] Then, the laser light L1 and the laser light L2 that have passed through the biconcave lens 41 and the collimation lens 42 are superimposed on each other via the mirrors 33 and 34 which are elements of the combiner unit 3, and then passed through the condenser lens 43 to be finally condensed and input to the galvanometer scanner unit 5.

[0036] shown in FIG. 4 Reference Example Even in the case of, similar to the above-described embodiment, the relative distance D along the axes of the laser lights L1 and L2 between the concave lens 41 and the convex lens 42 is made variably adjustable. For this purpose, at least one of the concave lens 41 and / or the convex lens 42 on each of the laser light axes L1 and L2 is supported by a linear motor carriage or other appropriate drive mechanism so as to be movable forward and backward along the optical axis direction.

[0037] For example, the concave lens 41 existing on the optical axis L1 and the concave lens 41 existing on the optical axis L2 are simultaneously controlled by a single axis so that these concave lenses 41 can both move forward and backward along the optical axis direction. The positions of the convex lenses 42 existing on the optical axes L1 and L2 along the optical axis directions are adjusted in advance in accordance with the wavelengths of the laser lights L1 and L2.

[0038] Needless to say, the adjustment of the relative distance D described above, in other words, the adjustment of the focal length F by the focus shifter unit 4, and the displacement of the direction of the optical axis by the galvanometer scanner unit 5 are synchronized.

[0039] In the example shown in FIG. 1, after the laser lights L1 and L2 having different wavelengths are superimposed by the mirrors 33 and 34 of the combiner unit 3, the focal length is adjusted by the lenses 41, 42, and 43 of the focus shifter unit 4. On the other hand, in the case shown in FIG. 4 Reference Example after adjusting the focal lengths of the respective laser lights L1 and L2 with the lenses 41 and 42 of the focus shifter unit 4, the laser lights L1 and L2 are superimposed by the mirrors 33 and 34 of the combiner unit 3. Thereby, the occurrence of chromatic aberration in the lenses 41 and 42 can be preferably avoided, and the laser lights L1 and L2 can be irradiated to a desired irradiation position on the workpiece W with higher accuracy using the galvanometer scanner 5.

[0040] shown in FIG. 5Reference Example On the optical axes of the laser beam L1 output from the laser light source 1 and the laser beam L2 output from the laser light source 2, the biconcave lens 41, the collimation lens 42, and the condenser lens 43 are arranged in sequence. In short, there are two biconcave lenses 41, two collimation lenses 42, and two condenser lenses 43.

[0041] Then, the laser beam L1 and the laser beam L2 that have passed through the biconcave lens 41, the collimation lens 42, and the condenser lens 43 are superimposed on each other via the mirrors 33 and 34 which are elements of the combiner unit 3, and then input to the galvanometer scanner unit 5.

[0042] As shown in FIG. 5 Reference Example Even in the case shown in the above embodiment, similar to the above embodiment, the relative distance D along the laser beam L1 and L2 axes between the concave lens 41 and the convex lens 42 can be variably adjusted. For this purpose, at least one of the concave lens 41 and / or the convex lens 42 on each of the laser beam L1 and L2 axes is supported by a linear motor carriage or other appropriate drive mechanism so as to be movable forward and backward along the optical axis direction.

[0043] For example, the biconcave lens 41 existing on the optical axis L1 and the biconcave lens 41 existing on the optical axis L2 are simultaneously controlled on one axis so that these biconcave lenses 41 can both move forward and backward along the optical axis direction. The positions of the convex lenses 42 existing on the optical axes L1 and L2 along the optical axis direction are adjusted in advance in accordance with the wavelengths of the laser beams L1 and L2.

[0044] Needless to say, the adjustment of the relative distance D described above, in other words, the adjustment of the focal length F by the focus shifter unit 4, is synchronized with the displacement of the optical axis direction by the galvanometer scanner unit 5.

[0045] As shown in FIG. 5 Reference ExampleThen, after adjusting the focal lengths of the respective laser beams L1 and L2 with the lenses 41, 42, and 43 of the focus shifter unit 4, the laser beams L1 and L2 are superimposed by the mirrors 33 and 34 of the combiner unit 3. As a result, the occurrence of chromatic aberration in the lenses 41, 42, and 43 can be suitably avoided, and the laser beams L1 and L2 can be irradiated onto a desired irradiation position on the workpiece W with higher accuracy using the galvanometer scanner 5.

[0046] In addition, the specific configuration of each part can be variously modified without departing from the gist of the present invention.

Explanation of Reference Numerals

[0047] 0…Laser processing apparatus 3…Combiner unit 4…Focus shifter unit 5…Galvanometer scanner unit L1, L2…Laser beams W…Workpiece

Claims

1. A combiner unit that superimposes a plurality of laser beams having different wavelengths on the same optical axis, a focus shifter unit that is disposed downstream of the combiner unit in the optical path and adjusts the focal length of the laser beams superimposed by the combiner unit, and a galvanometer scanner unit that is downstream of the focus shifter unit and displaces the direction of the optical axis of the laser beam directed toward the workpiece, and comprising a laser processing apparatus that synchronizes the adjustment of the focal length by the focus shifter unit and the displacement of the direction of the optical axis by the galvanometer scanner unit.

2. The laser processing apparatus according to claim 1, wherein there is no lens that allows the laser beam to pass between the galvanometer scanner unit and the workpiece.

3. The laser processing apparatus according to claim 1 or 2, wherein the focus shifter unit has a lens that adjusts the focal length of the laser beam by moving forward and backward along the optical axis of the laser beam.

4. The focus shifter unit has a lens that expands the diameter of the laser beam superimposed by the combiner unit and a lens that reduces the diameter of the laser beam that has passed through the lens, and expands and contracts the relative distance between the two lenses along the optical axis of the laser beam in synchronization with the displacement of the direction of the optical axis by the galvanometer scanner unit. The laser processing apparatus according to claim 1, 2, or 3.

5. It is for performing welding by irradiating a workpiece with a laser beam, and a blue laser beam and an infrared laser beam are superimposed by the combiner unit, and the superimposed laser beam is irradiated onto the workpiece through the focus shifter unit and the galvanometer scanner unit. The laser processing apparatus according to claim 1, 2, 3, or 4.

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