JP2020104167A - Laser processing device and beam rotator unit - Google Patents

Abstract

To realize taperless processing by trepanning processing.SOLUTION: In a processing device in which a beam rotator, a galvano-scanner and an fθ lens are provided in this order on an optical path of a laser beam from an emission source to a work-piece, operation for displacing the laser beam so that an irradiation position becomes a closed curve, such as a circle, as a scanning locus by the galvano-scanner, and operation for rotating an irradiation direction of the laser beam while inclining the irradiation direction by the beam rotator and the fθ lens are synchronized, and further, the laser beam enters the work-piece at an incident angle such that an outermost side of the laser beam passing range becomes perpendicular to the work-piece.SELECTED DRAWING: Figure 1

Description

The present invention relates to an apparatus for processing a workpiece using a laser beam and a beam rotator unit used in the apparatus, and more particularly to an apparatus and a unit for processing a through hole in the workpiece.

As one mode of processing using laser light, trepanning processing is widely known in which a laser beam is scanned on a workpiece in a circular shape, for example, to perform punching while leaving the core material. The trepanning process is used for forming a hole having a plane size larger than the beam diameter of laser light, or for taking out a core material having a plane size larger than the beam diameter.

On the other hand, a technique of forming a recess on the surface of the object to be processed by laser light, in addition to a pair of wedge prisms for adjusting the incident angle and wedge prisms for adjusting the radius of rotation, each of which is rotated at high speed by a servo motor A technique of controlling the shape of the side surface of the concave portion by using a laser processing device including a beam rotator incorporating a gradium lens which is an aplanatic lens and a processing head including a galvano scanner is already known (for example, See Patent Document 1).

JP, 2014-133242, A

When drilling holes in a workpiece by trepanning, there is a certain need to make the hole diameter uniform in the thickness direction, in other words, to make the hole a taperless straight column (eg, a regular column). ..

However, when the trepanning process is performed by scanning with the laser beam of the most general irradiation mode, which is irradiated vertically downward in such a manner that the focal point matches the processing target position of the workpiece, the side surface of the hole is tapered. Therefore, a columnar hole cannot be obtained.

On the other hand, Patent Document 1 discloses a mode in which the side surface of the concave portion is made perpendicular to the surface of the workpiece when forming the concave portion on the workpiece, but regarding the taperless trepanning processing, It has not been disclosed or suggested. Further, the processing device disclosed in Patent Document 1 has an essential aspect in which a beam rotator is provided with a gradium lens which is an aberration lens as a focusing optical system.

The present invention has been made in view of the above problems, and an object of the present invention is to realize a taperless drilling process by a trepanning process, and further to realize a trepanning process in which a taper state can be controlled.

In order to solve the above-mentioned problems, the invention of claim 1 is an apparatus for processing a workpiece by irradiating the workpiece with a laser beam, the source of the laser beam and the workpiece during processing. A stage on which a workpiece is placed horizontally, and an optical path of the laser beam from the emission source to the workpiece placed on the stage are sequentially provided from the side of the emission source. A beam rotator, a galvano scanner, and an fθ lens, and control means for controlling the operation of each part of the apparatus are provided, and the laser light that has passed through the fθ lens is irradiated onto the workpiece from above, and the beam rotator is , The incident laser beam is shifted to a position parallel to the incident direction, and is emitted while rotating the incident direction of the laser beam with respect to the beam rotator as a rotation axis, the galvano scanner is the workpiece of the laser beam. Is provided so that the irradiation position in the can be displaced, the laser light, while the laser light passing through the beam rotator and the galvano scanner passes through the fθ lens, while keeping the incident angle to the irradiation position at a predetermined angle, The irradiation direction with respect to the irradiation position is rotated, and the control means causes the galvano scanner to displace the irradiation position of the laser light along a predetermined closed curve, and the beam rotator and the fθ lens. The operation of rotating the irradiation direction of the laser light with respect to the irradiation position is synchronized.

A second aspect of the present invention is the laser processing apparatus according to the first aspect, wherein the laser beam is processed at an incident angle such that an outermost side of a range through which the laser beam passes is perpendicular to the workpiece. The feature is that it is incident on an object.

A third aspect of the present invention is the laser processing apparatus according to the second aspect, wherein the control unit causes the galvano scanner to make one round of the irradiation position of the laser light along a predetermined circle, The operation of rotating the irradiation direction of the laser light with respect to the irradiation position by one rotation is synchronized with the beam rotator and the fθ lens.

According to a fourth aspect of the present invention, in the laser processing apparatus according to the third aspect, the stage is provided so as to be able to move up and down, and the control means displaces the irradiation position of the laser light along the circle. The stage is moved and the workpiece is raised at every timing when one or more rounds are performed.

The invention of claim 5 is a beam rotator unit used in an apparatus for processing a workpiece by irradiating the workpiece with a laser beam, the beam rotator unit being sequentially provided on an optical path of the laser beam. A beam rotator, a galvano scanner, and an fθ lens which are different from each other, and control means for controlling the operation of each part of the beam rotator unit are provided, and the beam rotator places the incident laser light in a position parallel to the incident direction. Along with shifting, the laser light is emitted while rotating with the incident direction of the laser light with respect to the beam rotator as a rotation axis, the galvano scanner is provided to be able to displace the irradiation position of the laser light on the workpiece, and the laser light is When the laser light that has passed through the beam rotator and the galvano scanner passes through the fθ lens, the irradiation direction with respect to the irradiation position is rotated while maintaining the incident angle with respect to the irradiation position at a predetermined angle, and the control means Is an operation in which the galvano scanner displaces the irradiation position of the laser light along a predetermined closed curve, and the beam rotator and the fθ lens rotate the irradiation direction of the laser light with respect to the irradiation position. It is characterized by synchronizing with the motion.

According to the inventions of claims 1 to 5, it is possible to realize the drilling by the laser beam, in which the taper state is intentionally controlled.

Particularly, according to the inventions of claims 3 and 4, taperless drilling is realized.

It is a figure which shows the structure of the processing apparatus 100 typically. FIG. 6 is a diagram for explaining the roles of a beam rotator 20 and an fθ lens 40. 6 is a diagram schematically showing a state of laser light LB during trepanning processing by processing apparatus 100. FIG. FIG. 6 is a schematic cross-sectional view showing the progress of taperless processing realized by performing trepanning processing in the processing apparatus 100. 5 is a diagram showing an enlarged image of a through hole obtained in Example 1. FIG. 5 is a diagram showing an enlarged image of a through hole obtained in Example 2. FIG. FIG. 6 is a diagram showing an enlarged image of a through hole obtained in Example 3.

<Outline of processing equipment>
FIG. 1 is a diagram schematically showing a configuration of a processing apparatus 100 for performing trepanning processing according to the present embodiment. The processing apparatus 100 includes an emission source 10 of a laser beam LB, a beam rotator 20, a galvano scanner 30, an fθ lens 40, a control module 50 for controlling the operation of each part of the apparatus, and a workpiece (hereinafter, also referred to as a workpiece). ) The stage 70 on which W is mounted is mainly provided.

In the processing apparatus 100, the beam rotator 20, the galvano scanner 30, and the fθ lens 40 are provided from the side of the emission source 10 in the optical path of the laser beam LB from the emission source 10 to the workpiece W placed on the stage 70. It is provided in order. Then, under the control of the control module 50, the laser light LB emitted from the emission source 10 and sequentially passed through the beam rotator 20, the galvano scanner 30, and the fθ lens 40 is applied to the workpiece W, whereby the workpiece W is irradiated. Processing proceeds. In FIG. 1, mirrors 61 and 62 are provided between the emission source 10 and the beam rotator 20, and between the beam rotator 20 and the galvano scanner 30, respectively, and the laser beams LB are emitted by these mirrors 61 and 62. The optical path of the laser light LB is bent by the reflection, but this is for convenience of illustration and is not an essential aspect. Alternatively, due to the configuration of the processing apparatus 100, more mirrors may be used and the optical path of the laser light LB may be further bent.

The control module 50 turns on/off the emission of the laser light LB from the emission source 10, rotates the beam rotator 20, rotates (or swings) a galvano mirror (not shown) of the galvano scanner 30, and moves the stage 70. Controls the raising and lowering operations of the.

The stage 70 is a portion on which the work W is placed and fixed during processing. The work W placed on the stage 70 is irradiated with the laser light LB from the fθ lens 40 located above. The stage 70 is provided so that it can be raised and lowered at least in the vertical direction, and is raised and lowered in response to a drive signal from the control module 50. Alternatively, it may be configured so that biaxial movement (translation) operation and rotation operation in a horizontal plane can be performed. In such a case, these operations are also performed in response to the drive signal from the control module 50.

As the laser light LB, those having various wavelengths depending on the material and thickness of the work W, the desired processing mode, etc. may be selected, and the emission source 10 is also capable of emitting the selected laser light LB. It should be done.

FIG. 2 is a diagram for explaining the roles of the beam rotator 20 and the fθ lens 40. Note that, in FIG. 2, for simplicity of explanation, the galvano scanner 30 originally provided on the optical path between the beam rotator 20 and the fθ lens 40 is omitted. Further, the incident direction when the laser light LB is incident on the beam rotator 20 (more specifically, on the prism 21) is the axis AX1.

As shown in FIG. 2, the beam rotator 20 has a configuration in which a pair of prisms 21 and 22 are incorporated inside a hollow motor 23. The pair of prisms 21 and 22 is incorporated in the hollow motor 23 so that the laser light LB that has entered the prism 21 along the axis AX1 is emitted from the prism 22 at a position shifted by a predetermined distance in parallel to the axis AX1. It becomes. In other words, the pair of prisms 21 and 22 are arranged so that the optical path position of the laser light LB at the time of emission from the beam rotator 20 is shifted by a predetermined distance from the optical path position of the laser light LB at the time of incidence on the beam rotator 20. It is built in the hollow motor 23.

More specifically, the laser light LB traveling from the prism 21 to the prism 22 is once inclined by a predetermined angle α with respect to the axis AX1, but is emitted from the prism 22 (that is, from the beam rotator 20) to the outside. The emission direction of the laser light LB is parallel to the axis AX1.

In addition to this, in the beam rotator 20, the hollow motor 23 is adapted to rotate about the axis AX1 as a rotation axis as shown by an arrow AR2. As a result of the combination of such rotation and the above-mentioned shift, the laser light LB is emitted from the beam rotator 20 in a manner of rotating in parallel with and around the axis AX1.

If the contribution of the galvano scanner 30 is ignored (or if the galvano scanner 30 does not change the position of the laser light LB), the laser light LB emitted from the beam rotator 20 is kept parallel to the axis AX1. It is incident on the fθ lens 40 which is arranged with AX1 as the axial center. The fθ lens 40 is provided so as to deflect the incident laser beam LB toward a position on the extension line of the axis AX1 in the work W. As a result, the laser light LB is irradiated onto the work W at the predetermined incident angle β.

However, the beam rotator 20 is rotating as described above. Therefore, the incident position of the laser light LB with respect to the fθ lens 40 also rotates around the axis AX1, and thus the emitting position of the laser light LB from the fθ lens 40 also rotates around the axis AX1. However, since the optical path position of the laser light LB shifted by the beam rotator 20 is isotropic with respect to the axis AX1, the laser light LB is applied to the same position of the work W.

That is, the beam rotator 20 and the fθ lens 40, when the contribution of the galvano scanner 30 is ignored, cause the laser beam LB to be incident on the same position of the work W while rotating while maintaining a predetermined incident angle β. Means having. In other words, it can be said that the beam rotator 20 and the fθ lens 40 have the effect of rotating the laser beam LB so that the direction of incidence of the laser light LB with respect to the irradiation position is constantly changed.

In the actual processing device 100, as described above, the galvano scanner 30 is provided on the optical path between the beam rotator 20 and the fθ lens 40. Under the control of the control module 50, the galvano scanner 30 is provided to displace the irradiation position of the laser beam LB on the work W to an arbitrary position as indicated by an arrow AR1 in FIG. More specifically, the galvano scanner 30 is provided so that the irradiation position of the laser beam LB can be displaced within a predetermined range in the two horizontal axis directions. The work W can be scanned by the laser beam LB by operating the galvano scanner 30. In such a case, the displacement of the irradiation position of the laser light LB by the galvano scanner 30 (that is, the scanning by the laser light LB) is virtually the original position (when the laser light LB is incident on the beam rotator 20) on the axis AX1. Position) can be regarded as a displacement parallel to the position. Therefore, the irradiation of the laser beam LB rotates while maintaining the incident angle β, which is realized by the displacement of the irradiation position according to the operation of the galvano scanner 30 and the action of the beam rotator 20 and the fθ lens 40 described above. This is done in combination with the incidence of the incident light on the irradiation position.

<trepanning processing>
Next, trepanning processing by the processing apparatus 100 having the above-described configuration will be described. FIG. 3 is a diagram schematically showing a state of the laser light LB at the time of trepanning processing by the processing device 100. FIG. 4 is a schematic cross-sectional view showing the progress of taperless drilling (hereinafter, also simply referred to as taperless processing) realized by performing trepanning processing in the processing apparatus 100.

In the following, for simplification of description, as shown by an arrow AR4 in FIG. 3, the irradiation position of the laser beam LB (typically the converging point F) is displaced along a predetermined horizontal circle C ( The case where the trepanning process is performed in a manner of (circulation), that is, in a manner in which the scanning locus by the laser beam LB becomes a circle C is targeted.

The displacement (circular scanning) of the laser beam LB along the circle C is realized by driving the galvano scanner 30 based on the scanning signal from the control module 50. Then, in the processing apparatus 100 according to the present embodiment, due to the displacement of the laser light LB by the galvano scanner 30 along the circle C, the laser light LB by the rotation of the beam rotator 20 as shown by an arrow AR3 in FIG. The trepanning process is performed in a state in which the change in the direction of irradiation is synchronized.

At the time of actual processing, the control module 50 issues an on signal for emitting the laser beam LB to the emission source 10 in a state where the beam rotator 20 and the galvano scanner 30 are synchronized, and the emission source 10 responds to this. Then, the emission of the laser beam LB is started.

More specifically, while the irradiation direction of the laser light LB with respect to the irradiation position makes one rotation by the operation of the beam rotator 20, both operations are performed so that the laser light LB makes exactly one rotation on the circle C by the galvano scanner 30. It is controlled synchronously. This is because the control module 50 causes the galvano scanner 30 to make one round of a circle C according to the timing at which the control module 50 receives the timing signal generated by the beam rotator 20 each time the hollow motor 23 makes one revolution. It is realized by giving a scanning signal for execution.

In such a case, the laser light LB must move along the circle C while rotating within the conical envelope surface CF having the virtual axis AX2 orthogonal to the horizontal plane including the circle C as the central axis on the circle C. become. Then, the shape of the through hole at the time of trepanning is determined by the relationship between the irradiation position of the laser light LB on the circle C and the rotational position (direction of irradiation of the laser light at the irradiation position) within the envelope surface CF. It will be.

The taperless processing is a typical example thereof. That is, the synchronous control of the beam rotator 20 and the galvano scanner 30 by the control module 50 makes the passing range of the laser beam LB irrespective of the position of the laser beam LB emitted from the fθ lens 40 on the circle C. In a mode that is included inside the circle C and the outermost side of the passing range is along the virtual axis AX2 that is orthogonal to the horizontal plane including the circle C on the circle C, that is, the outermost side of the passing range is the work. When it is performed in a mode perpendicular to W, taperless processing is realized.

It should be noted that the virtual axis AX2 can also be considered as a parallel movement of the virtual axis AX1 shown in FIG. 2 as the irradiation position of the laser beam LB by the galvano scanner 30 is displaced. Therefore, in the taperless processing, the angle formed between the outermost side of the passage range of the laser light LB and the optical axis is the beam rotator 20 regardless of the position on the circle C where the irradiation position moved by the galvano scanner 30 is located. It can be said that it is realized by inclining the laser light LB under the condition that coincides with the incident angle β realized by.

As an example, as shown in FIG. 4A, with respect to a plate-shaped work W horizontally arranged on a stage 70 (not shown), a planned surface P (a cross-sectional view) along the thickness direction thereof. 4 is shown as a linear shape), considering the case where a hole having a regular cylindrical shape with a diameter D is to be bored by the taperless processing of the above-mentioned aspect, the laser beam LB is first set to the maximum in the passing range. In a state where the laser beam LB is incident at an incident angle β whose outside is perpendicular to the work W, while the irradiation direction is rotated as shown by an arrow AR5, the irradiation position is changed as shown by an arrow AR6. It is displaced along the scheduled surface P. However, the incident angle β is preferably an angle at which interference or reflection of laser light does not occur. Further, the outermost side of the passage range of the laser light LB does not necessarily need to be strictly perpendicular to the work W, and in practical use, it may be an angle close to perpendicular.

Thereafter, in response to the drive signal from the control module 50 at each timing when the displacement is performed at least once or a plurality of times, in other words, at each timing when the beam rotator 20 makes one rotation or a plurality of rotations of the laser light LB. Then, the work W is raised by a predetermined distance by operating the stage 70. As a result, the converging point F enters the inside of the work W in the thickness direction, and as shown in FIG. 4B, the work W has a machining groove along the planned surface P from the surface toward the thickness direction. (Processing mark) G is gradually formed. At this time, the method of tilting and rotating the laser light LB is the same as that at the time of starting the processing, and therefore the laser light LB does not extend outside the planned surface P. The rising timing of the work W may be appropriately determined according to the material of the work W, the intensity of the laser light LB, and the like.

The stage 70 may be moved up and down as long as the stage 70 is moved up and down relative to the fθ lens 40. It may be a mode of moving up and down without changing the optical distance inside.

Alternatively, the circular scanning of the laser beam LB by the operation of the galvano scanner 30 and the raising of the work W by the operation of the stage 70 may be performed in a synchronized manner. In this case, the focal point F of the laser light LB enters the inside of the work W while drawing a spiral locus.

By repeating the orbital scanning of the laser beam LB and the raising of the work W, the groove G finally penetrates the work W along the planned surface P as shown in FIG. 4C. Then, by removing the cylindrical portion surrounded by the groove G as shown by the arrow AR7, the side surface S becomes both the front surface Wa and the back surface Wb of the work W as shown in FIG. 4D. A through hole H which is perpendicular to the above is formed. That is, the taperless processing is completed.

When the thickness of the work W is small, the groove G is penetrated from the front surface Wa to the back surface Wb along the planned surface P without moving the work W upward by moving the stage 70 in this way. It is possible.

By the way, when forming a cylindrical through hole, it is necessary to make the scanning locus of the laser beam LB circular, but by changing the shape of the closed curve (including polygon) formed by the scanning locus, the through holes of other shapes can be formed. It is also possible to open. For example, if the galvano scanner 30 is controlled so that the scanning locus by the laser light LB becomes a rectangular shape, it is possible to perform processing to form a rectangular through hole. If the laser light LB is incident on the work W at an incident angle that is perpendicular to the work W, the rectangular through hole can be tapered.

As described above, according to the present embodiment, in the processing apparatus in which the beam rotator, the galvano scanner, and the fθ lens are provided in this order in the optical path of the laser light from the emission source to the workpiece, the galvano scanner is used. The operation of displacing the laser light so that the irradiation position becomes a scanning locus of a closed curve such as a circle, and the operation of rotating the irradiation direction by tilting the irradiation direction of the laser light by the beam rotator and the fθ lens. By synchronizing and making the laser light incident on the work piece at an incident angle such that the outermost side of the laser light passage range is perpendicular to the work piece, there is no taper to the work piece. Drilling can be performed.

<Modification>
In the above-described embodiment, in order to realize the taperless processing, the laser light is incident at an incident angle such that the outermost side of the laser light passage range is perpendicular to the workpiece. Instead, the laser light is made incident at an incident angle such that the innermost side of the laser light passage range is perpendicular to the workpiece, and the laser light is made incident in a phase opposite to that of the above-described embodiment. In such a case, it is possible to intentionally perform a drilling process in which the through hole has a tapered shape, preferably, a tapered shape is controlled. Further, by varying the tilted state of the laser beam throughout the processing, or stepwise or continuously during the processing, it is possible to perform drilling of various hole shapes. This means that by controlling the tilted state of the laser light, it is possible to perform the punching process while intentionally controlling the tapered state.

(Example 1)
In this example, a hole having a diameter of 200 μm was drilled in an alumina ceramic plate having a thickness of 0.62 mm. The processing conditions were as follows.
Laser condition→wavelength=532 nm, pulse width<50 ps, repetition frequency=100 kHz, output=7.5 W;
Beam rotator rotation speed=10000 rpm;
Z-axis feed pitch=12 μm.

FIG. 5 is a diagram showing an enlarged image of a through hole obtained by processing. FIG. 5(a) is an image of the alumina ceramic plate viewed from the side after cutting the alumina ceramic plate in a cross section passing through the through hole, and FIG. 5(b) is an image of the surface of the alumina ceramic plate after the cutting. is there.

From FIG. 5, it is confirmed that the taperless through hole is well formed.

(Example 2)
In this embodiment, a SiC plate having a thickness of 0.36 mm was perforated with a diameter of 300 μm. The processing conditions were as follows.
Laser condition→wavelength=532 nm, pulse width<15 ns, repetition frequency=80 kHz, output=4.0 W;
Beam rotator rotation speed = 5000 rpm;
Z-axis feed pitch=20 μm.

FIG. 6 is a diagram showing an enlarged image of a through hole obtained by processing. FIG. 6(a) is an image of the side surface of the through hole after the SiC plate is cut along the cross section passing through the through hole, and FIG. 6(b) is an image of the surface of the SiC plate after the through hole is formed. ..

From FIG. 6, it is confirmed that the taperless through hole is well formed.

(Example 3)
In this example, a Si plate having a thickness of 0.49 mm was perforated with a diameter of 500 μm. The processing conditions were as follows.
Laser condition→wavelength=532 nm, pulse width<15 ns, repetition frequency=50 kHz, output=7.5 W;
Beam rotator rotation speed = 5000 rpm;
Z-axis feed pitch=60 μm.

FIG. 7 is a diagram showing an enlarged image of a through hole obtained by processing. FIG. 7A is an image of the Si plate viewed from the side after dividing the Si plate in a cross section passing through the through hole, and FIG. 7B is an image of the surface of the Si plate after the through hole is formed. ..

From FIG. 7, it is confirmed that the taperless through hole is well formed.

10 Output Source 20 Beam Rotator 21, 22 Prism 23 Hollow Motor 30 Galvano Scanner 40 fθ Lens 50 Control Module 70 Stage 100 Processing Device LB Laser Light F Focusing Point H Through Hole P Planned Surface W Workpiece

Claims (5)

A device for processing a workpiece by irradiating the workpiece with a laser beam,
An emission source of the laser light,
A stage on which the workpiece is placed horizontally during processing,
A beam rotator, a galvano scanner, and an fθ lens sequentially provided from the side of the emission source on the optical path of the laser light from the emission source to the workpiece mounted on the stage,
Control means for controlling the operation of each part of the device,
Equipped with
The laser beam that has passed through the fθ lens is applied to the workpiece from above,
The beam rotator shifts the incident laser light to a position parallel to the incident direction, and emits while rotating the incident direction of the laser light with respect to the beam rotator as a rotation axis.
The galvano scanner is provided so that the irradiation position of the laser light on the workpiece can be displaced.
The laser light is rotated in the irradiation direction with respect to the irradiation position while keeping the incident angle with respect to the irradiation position at a predetermined angle by the laser light passing through the beam rotator and the galvano scanner through the fθ lens. ,
The control means causes the galvano scanner to displace the irradiation position of the laser light along a predetermined closed curve, and the irradiation direction of the laser light with respect to the irradiation position by the beam rotator and the fθ lens. Synchronize with the action of rotating
A laser processing device characterized in that The laser processing apparatus according to claim 1, wherein
Injecting the laser light into the work piece at an incident angle such that the outermost side of the passage range of the laser light is perpendicular to the work piece.
A laser processing device characterized in that The laser processing apparatus according to claim 2, wherein
The control means causes the galvano scanner to make one round of the irradiation position of the laser light along a predetermined circle, and the irradiation of the laser light to the irradiation position by the beam rotator and the fθ lens. Synchronize the action of rotating the direction once,
A laser processing device characterized in that The laser processing apparatus according to claim 3, wherein
The stage is provided so that it can move up and down,
The control means moves the stage and raises the workpiece at every timing when the irradiation position of the laser light along the circle is displaced once or plural times.
A laser processing device characterized in that A beam rotator unit used in an apparatus for processing a workpiece by irradiating the workpiece with a laser beam,
A beam rotator, a galvano scanner, and an fθ lens that are sequentially provided on the optical path of the laser beam; and a control unit that controls the operation of each part of the beam rotator unit,
The beam rotator shifts the incident laser light to a position parallel to the incident direction, and emits while rotating the incident direction of the laser light with respect to the beam rotator as a rotation axis.
The galvano scanner is provided so that the irradiation position of the laser light on the workpiece can be displaced.
The laser light is rotated in the irradiation direction with respect to the irradiation position while keeping the incident angle with respect to the irradiation position at a predetermined angle by the laser light passing through the beam rotator and the galvano scanner through the fθ lens. ,
The control means causes the galvano scanner to displace the irradiation position of the laser light along a predetermined closed curve, and the irradiation direction of the laser light with respect to the irradiation position by the beam rotator and the fθ lens. Synchronize with the action of rotating
Beam rotator unit, which is characterized by