CN111375913A

CN111375913A - Laser processing device and beam rotator unit

Info

Publication number: CN111375913A
Application number: CN201911326219.XA
Authority: CN
Inventors: 林尚久; 佐岛德武; 前田宪一; 栗山规由; 熊谷透; 清水政二
Original assignee: Mitsuboshi Diamond Industrial Co Ltd
Current assignee: Mitsuboshi Diamond Industrial Co Ltd
Priority date: 2018-12-28
Filing date: 2019-12-20
Publication date: 2020-07-07
Also published as: KR20200083249A; TW202035054A; JP2020104167A

Abstract

The invention realizes the zero-taper processing based on the nesting processing. In the present invention, a beam rotator, a scanning galvanometer, and an f θ lens are provided in this order in an optical path of laser light from an emission source to a workpiece, and an operation of displacing the laser light by the scanning galvanometer so that an irradiation position becomes a scanning locus of a closed curve such as a circle, and an operation of rotating the irradiation direction while inclining the irradiation direction of the laser light by the beam rotator and the f θ lens are synchronized, and the laser light is incident on the workpiece at an incident angle at which the outermost side of a laser light passage range is perpendicular to the workpiece.

Description

Laser processing device and beam rotator unit

Technical Field

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

Background

Trepanning is a well-known method of machining using a laser beam, in which a laser beam is scanned, for example, in a circular shape, over a workpiece to be machined, thereby performing hole drilling while leaving a core material. The trepanning processing is processing for opening a hole having a planar size larger than the beam diameter of the laser, or processing for taking out a core material having a planar size larger than the beam diameter.

On the other hand, there is known a technique of forming a concave portion on a surface of a processing object by laser light, in which a shape of a side surface of the concave portion is controlled by using a laser processing device having a pair of wedges for adjusting an incident angle and a wedge for adjusting a rotation radius, which are rotated at high speed by a servo motor, respectively, and a beam rotator in which a GRADIUM lens as an aberration-eliminating lens is incorporated, and a processing head including a scanning galvanometer (for example, see patent document 1).

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2014-133242.

Problems to be solved by the invention

In the case of drilling a workpiece by trepanning, it is necessary to make the hole diameter uniform in the thickness direction, in other words, to make the hole a straight columnar shape (for example, a right columnar shape) without a taper.

However, in the case of the method of aligning the focal point with the processing target position of the workpiece, when trepanning is performed by scanning with the laser beam of the most general irradiation method that irradiates the workpiece vertically downward, the side surface of the hole becomes a conical shape, and a straight columnar hole cannot be obtained.

On the other hand, patent document 1 discloses a method of making a side surface of a recess perpendicular to a surface of a workpiece when the recess is formed in the workpiece, but does not disclose or suggest any taper-free trepanning. In the processing apparatus disclosed in patent document 1, a gradim lens, which is an anti-aberration lens as a condensing optical system, is necessarily provided in the beam rotator.

Disclosure of Invention

The present invention has been made in view of the above problems, and an object of the present invention is to: the non-taper hole drilling processing is realized through the trepanning processing, and then the trepanning processing capable of controlling the taper state is realized.

Means for solving the problems

In order to solve the above problem, the invention of claim 1 is a laser processing apparatus for processing a workpiece by irradiating the workpiece with a laser beam, the laser processing apparatus including: an emission source of the laser; a table on which the workpiece is horizontally placed during machining; a beam rotator, a scanning galvanometer, and an f θ lens, which are provided on an optical path of the laser beam from the emission source to the workpiece placed on the table in this order from the emission source side; and a control unit that controls operations of the respective units of the apparatus, wherein the laser light having passed through the f θ lens is irradiated from above onto the workpiece, the beam rotator shifts the incident laser light to a position parallel to an incident direction and emits the laser light while rotating the laser light about an incident direction of the beam rotator as a rotation axis, the scanning galvanometer is provided so as to be able to displace an irradiation position of the laser light on the workpiece, and the laser light having passed through the beam rotator and the scanning galvanometer passes through the f θ lens, whereby the laser light is rotated in the irradiation direction with respect to the irradiation position while maintaining an incident angle thereof with respect to the irradiation position at a predetermined angle, and the control unit synchronizes operations of the scanning galvanometer displacing the irradiation position of the laser light along a predetermined closed curve, and an operation of rotating the laser beam in the irradiation direction with respect to the irradiation position by the beam rotator and the f θ lens.

The invention according to claim 2 is the laser processing apparatus according to claim 1, wherein the laser beam is incident on the workpiece at an incident angle at which an outermost side of a passing range of the laser beam is perpendicular to the workpiece.

The invention according to claim 3 is the laser processing apparatus according to claim 2, wherein the control unit synchronizes an operation of the scanning galvanometer rotating the irradiation position of the laser beam by one rotation along a predetermined circle with an operation of rotating the laser beam by one rotation in the irradiation direction with respect to the irradiation position by the beam rotator and the f θ lens.

The invention of claim 4 is the laser processing apparatus of claim 3, wherein the table is provided to be movable up and down, and the control unit moves the table to raise the workpiece every time the irradiation position of the laser beam is displaced by one or more circles along the circle.

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 including a beam rotator, a scanning galvanometer, an f θ lens, and a control unit for controlling operations of the respective parts of the beam rotator unit, the beam rotator being provided in this order on an optical path of the laser beam, the beam rotator being configured to shift an incident position of the laser beam in the workpiece to a position parallel to an incident direction and to emit the laser beam while rotating the laser beam around an incident direction of the laser beam with respect to the beam rotator as a rotation axis, the scanning galvanometer being configured to displace an irradiation position of the laser beam on the workpiece, and the laser beam having passed through the beam rotator and the scanning galvanometer being passed through the f θ lens, whereby the laser beam maintains an incident angle thereof with respect to the irradiation position at a predetermined angle and is caused to pass through the f θ lens The control unit synchronizes an operation of displacing the irradiation position of the laser beam along a predetermined closed curve by the scanning galvanometer and an operation of rotating the laser beam in the irradiation direction with respect to the irradiation position by the beam rotator and the f θ lens.

Effects of the invention

According to the inventions of claims 1 to 5, the state of the taper is intentionally controlled, and laser-based hole forming processing is realized.

In particular, according to the inventions of claim 3 and claim 4, the boring work without taper is realized.

Drawings

Fig. 1 is a diagram schematically showing the configuration of a processing apparatus 100.

Fig. 2 is a diagram for explaining the operation of the beam rotator 20 and the f θ lens 40.

Fig. 3 is a diagram schematically showing a state of the laser beam LB at the time of trepanning by the machining apparatus 100.

Fig. 4 is a schematic cross-sectional view showing a case where the blank working is performed by the working apparatus 100 to perform the zero taper working.

Fig. 5 is a diagram showing an enlarged image of the through-hole obtained in example 1.

Fig. 6 is a diagram showing an enlarged image of the through-hole obtained in example 2.

Fig. 7 is a diagram showing an enlarged image of the through-hole obtained in example 3.

Detailed Description

< outline of processing apparatus >

Fig. 1 is a diagram schematically showing the configuration of a processing apparatus 100 for performing trepanning in the present embodiment. The machining apparatus 100 mainly includes an emission source 10 of a laser beam LB, a beam rotator 20, a scanning galvanometer 30, an f θ lens 40, a control module 50 for controlling operations of respective parts of the apparatus, and a table 70 on which a workpiece (hereinafter, also referred to as a workpiece) W is placed.

In the processing apparatus 100, in brief, a beam rotator 20, a scanning galvanometer 30, and an f θ lens 40 are provided in this order 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 mounted on the stage 70. Under the control of the control module 50, the laser beam LB is emitted from the emission source 10, and is irradiated onto the workpiece W through the beam rotator 20, the scanning galvanometer 30, and the f θ lens 40 in this order, thereby processing the workpiece W. In fig. 1, a mirror 61 and a mirror 62 are respectively provided between the emission source 10 and the beam rotator 20 and between the beam rotator 20 and the scanning galvanometer 30, and the optical path of the laser beam LB is bent by reflecting the laser beam LB by the mirror 61 and the mirror 62, which is convenient and not necessary for illustration. Alternatively, depending on the configuration of the processing apparatus 100, the optical path of the laser beam LB may be further bent using more mirror surfaces.

The control module 50 controls on/off operation of the laser beam LB emitted from the emission source 10, rotation operation of the beam rotator 20, rotation (or oscillation) operation of the galvanometer of the scanning galvanometer 30 (not shown), and up/down operation of the table 70.

The table 70 is a portion on which the workpiece W is placed and fixed during machining. The laser beam LB is irradiated from the f θ lens 40 positioned above the workpiece W placed on the stage 70. The table 70 is vertically movable at least and is moved up and down in accordance with a drive signal from the control module 50. Alternatively, the device may be configured to be capable of performing a two-axis movement (parallel movement) operation or a rotation operation in the horizontal plane. In this case, these operations are also performed in response to a drive signal from the control module 50.

The laser beam LB may be selected from various wavelengths depending on the material and thickness of the workpiece W and the desired processing method, and the emission source 10 may be prepared as long as it can emit the selected laser beam LB.

Fig. 2 is a diagram for explaining division of the beam rotator 20 and the f θ lens 40. In fig. 2, the scanning galvanometer 30 provided on the optical path between the beam rotator 20 and the f θ lens 40 is omitted in the related art for the sake of simplicity of description. The incident direction of the laser beam LB upon the beam rotator 20 (more specifically, the prism 21) is defined as an axis AX 1.

As shown in fig. 2, the beam rotator 20 has a structure in which a pair of

prisms

21 and 22 are assembled inside a hollow motor 23. The pair of

prisms

21 and 22 are incorporated in the hollow motor 23 in such a manner that the laser beam LB incident on the prism 21 along the axis AX1 is emitted from the prism 22 at a position shifted by a predetermined distance in parallel with the axis AX 1. In other words, the pair of

prisms

21 and 22 are incorporated in the hollow motor 23 such that the optical path position when the laser beam LB is emitted from the beam rotator 20 is offset by a predetermined distance from the optical path position when the laser beam LB is incident on the beam rotator 20.

More specifically, the laser beam LB from the prism 21 to the prism 22 is once inclined at a predetermined angle α with respect to the axis AX1, but the emission direction of the laser beam LB when emitted from the prism 22 (i.e., from the beam rotator 20) to the outside is parallel to the axis AX 1.

In addition, in the beam rotator 20, the hollow motor 23 rotates about the axis AX1 as a rotation axis as indicated by an arrow AR 2. As a result of this rotation in combination with the above-described offset, the exit of the laser light LB from the beam rotator 20 is implemented in a manner parallel to the axis AX1 and rotating around the axis AX 1.

When the influence of the scanning galvanometer 30 is ignored (or if the scanning galvanometer 30 does not change the position of the laser beam LB), the laser beam LB emitted from the beam rotator 20 is kept parallel to the axis AX1, and is incident on an f θ lens 40 disposed with the axis AX1 as the axis center, the f θ lens 40 is disposed so as to deflect the incident laser beam LB toward a position on an extension line of the axis AX1 in the workpiece W, whereby the laser beam LB is irradiated at a prescribed incident angle β to the workpiece W.

Only, as described above, the beam rotator 20 is rotated. Therefore, the incident position of the laser beam LB to the f θ lens 40 also rotates around the axis AX1, and the emission position of the laser beam LB emitted from the f θ lens 40 also rotates around the axis AX 1. However, since the optical path position of the laser beam LB shifted by the beam rotator 20 is isotropic with respect to the axis AX1, the laser beam LB is irradiated to the same position of the workpiece W.

This means that, when the influence of the scanning galvanometer 30 is ignored, the beam rotator 20 and the f θ lens 40 have a function of rotating the laser beam LB with respect to the workpiece W while keeping the same position thereof at a predetermined incident angle β and, in other words, the beam rotator 20 and the f θ lens 40 can be said to have a function of continuously changing the direction of incidence of the rotating laser beam LB with respect to the irradiation position.

In the actual machining apparatus 100, as described above, the scanning galvanometer 30 is provided on the optical path between the beam rotator 20 and the f θ lens 40, and the scanning galvanometer 30 is provided so that the irradiation position of the laser beam LB with respect to the workpiece W is displaced to an arbitrary position as indicated by an arrow AR1 in fig. 1 under the control of the control module 50. more specifically, the scanning galvanometer 30 is provided so that the irradiation position of the laser beam LB is freely displaced within a predetermined range in the horizontal two-axis direction, and further, based on the operation of the scanning galvanometer 30, the scanning of the workpiece W by the laser beam LB is enabled, and in this case, the irradiation of the laser beam LB is performed by combining the displacement of the irradiation position of the laser beam LB by the scanning galvanometer 30 (that is, the scanning by the laser beam LB) with the axis AX1 virtually displaced to a position parallel to the original position (the position at which the laser beam LB enters the beam rotator 20) and the irradiation position of the laser beam LB with the incidence angle β maintained by the operation of the beam rotator 20 and the θ lens 40.

< processing of nesting >

Next, the nesting process 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 beam LB when the machining apparatus 100 performs the trepanning process. Fig. 4 is a schematic cross-sectional view showing a case where trepanning is performed by the machining apparatus 100 to perform drilling of a hole having no taper (hereinafter, simply referred to as "zero taper machining").

In the following description, for the sake of simplicity of explanation, as shown by an arrow AR4 in fig. 3, the nesting process is performed so that the irradiation position of the laser beam LB (represented by the focal point F) is displaced (rounded) along a predetermined horizontal circle C, that is, so that the scanning locus by the laser beam LB is a circle C.

The displacement of the laser LB along the circle C (wrap around scanning) is achieved by driving the scanning galvanometer 30 based on a scanning signal from the control module 50. In the processing apparatus 100 of the present embodiment, the nesting processing is performed in a state in which the change in the irradiation direction of the laser beam LB caused by the rotation of the beam rotator 20 indicated by the arrow AR3 in fig. 3 is synchronized with the displacement of the laser beam LB along the circle C caused by the scanning galvanometer 30.

In actual machining, the control module 50 sends an on signal for emitting the laser beam LB to the emission source 10 in a state where synchronization between the beam rotator 20 and the scanning galvanometer 30 is established, and the emission source 10 starts emitting the laser beam LB in response to the on signal.

More specifically, when the laser beam LB is rotated once in the irradiation direction with respect to the irradiation position by the operation of the beam rotator 20, the laser beam LB is rotated exactly once on the circle C by the scanning galvanometer 30, and the operations of both are controlled in synchronization with each other. The timing signal transmitted from the beam rotator 20 every rotation of the hollow motor 23 is received by the control module 50, and the control module 50 supplies a scanning signal for performing one-turn scanning on the circle C to the scanning galvanometer 30 according to this reception timing, thereby realizing synchronous control.

In this case, the laser beam LB moves along the circle C while rotating within a conical envelope CF centered on a virtual axis AX2 on the circle C and orthogonal to a horizontal plane including the circle C. Then, the shape of the through hole in the trepanning process is determined based on the relationship between the irradiation position of the laser beam LB on the circle C and the rotational position (irradiation direction of the laser beam toward the irradiation position) within the envelope CF.

Conitless processing is one representative way of doing this. That is, the control module 50 synchronously controls the beam rotator 20 and the scanning galvanometer 30, and the zero-taper machining is performed in such a manner that the passage range of the laser beam LB is included inside the circle C and the outermost side of the passage range is along the virtual axis AX2 on the circle C and orthogonal to the horizontal plane including the circle C, that is, the outermost side of the passage range is perpendicular to the workpiece W, regardless of the position of the laser beam LB emitted from the f θ lens 40 on the circle C.

The virtual axis AX2 can also be considered to be a result of the virtual axis AX1 shown in fig. 2 moving in parallel with the displacement of the irradiation position of the laser beam LB by the scanning galvanometer 30, and therefore, the zero-taper processing can be realized by tilting the laser beam LB under the condition that the angle formed by the optical axis and the outermost side of the laser beam LB passage range coincides with the incident angle β by the beam rotator 20, regardless of where the irradiation position moved by the scanning galvanometer 30 is located on the circle C.

As an example, as shown in fig. 4 (a), when a plate-shaped workpiece W horizontally disposed on a not-shown table 70 is to be drilled with a right circular cylindrical hole having a diameter D by the above-described non-taper machining along a machining predetermined plane P (shown as a line in fig. 4 as a cross-sectional view) in the thickness direction, the laser beam LB is first incident at an incident angle β at which the outermost side of the passage range is perpendicular to the workpiece W, and in this state, the irradiation position is displaced along the machining predetermined plane P as shown by an arrow AR6 while rotating the irradiation direction as shown by an arrow AR 5.

Thereafter, the stage 70 is operated in response to a drive signal from the control module 50 to raise the workpiece W by a predetermined distance every time the displacement is performed for at least one or more revolutions, in other words, every time the beam rotator 20 rotates the laser beam LB for one or more revolutions. As a result, the converging point F enters the inside of the workpiece W in the thickness direction, and as shown in fig. 4 (b), a machining groove (machining trace) G is formed in the workpiece W from the front surface toward the thickness direction along the machining-planned plane P. At this time, since the inclination and rotation of the laser beam LB are the same as those at the start of machining, the laser beam LB does not go beyond the machining-scheduled surface P. The timing at which the workpiece W rises can be appropriately determined depending on the material of the workpiece W, the intensity of the laser beam LB, and the like.

The elevation of the table 70 may be performed as long as the table is elevated with respect to the f θ lens 40, and the optical system may be elevated instead of the elevation of the table 70 or in conjunction with the elevation of the table 70 without changing the optical distance in the optical system including the f θ lens 40.

Alternatively, the circling scanning of the laser beam LB by the movement of the scanning galvanometer 30 and the raising of the workpiece W by the movement of the table 70 may be performed in synchronization with each other. In this case, the converging point F of the laser beam LB enters the inside of the workpiece W while tracing a spiral trajectory.

By repeating the circling scan of the laser beam LB and the raising of the workpiece W, finally, as shown in fig. 4 (c), the groove G penetrates the workpiece W along the predetermined machining plane P. When the columnar portion surrounded by the groove G is separated as indicated by the arrow AR7, a through hole H having a side surface S perpendicular to both the front surface Wa and the back surface Wb of the workpiece W is formed as shown in fig. 4 (d). That is, the zero taper processing is completed.

When the thickness of the workpiece W is small, the groove G can penetrate from the front surface Wa to the back surface Wb along the planned processing plane P without moving the workpiece W upward by operating the table 70 in this manner.

However, in the case of opening a cylindrical through hole, the scanning locus of the laser beam LB needs to be circular, but a through hole having another shape can be opened by changing the shape of a closed curve (including a polygon) forming the scanning locus. For example, if the scanning galvanometer 30 is controlled to make the scanning locus of the laser beam LB rectangular, the machining for forming a rectangular through hole can be performed, and in this case, the laser beam LB is made incident on the workpiece W at an incident angle perpendicular to the workpiece W at the outermost side of the passage range of the laser beam LB, and if such a relationship is satisfied, the rectangular through hole can be made free of taper.

As described above, according to the present embodiment, in the optical path of the laser light from the emission source to the workpiece, the machining device is provided with the beam rotator, the scanning galvanometer, and the f θ lens in this order, and the operation of shifting the laser light by the scanning galvanometer so that the irradiation position becomes the scanning locus of a closed curve such as a circle and the operation of rotating the irradiation direction while inclining the laser light irradiation direction by the beam rotator and the f θ lens are synchronized with each other, and the laser light is made to enter the workpiece at the incident angle at which the outermost side of the passage range becomes perpendicular to the workpiece, thereby enabling the non-tapered hole drilling of the workpiece.

< modification example >

In the above embodiment, the non-taper machining is realized by making the laser beam incident at the angle of incidence perpendicular to the workpiece at the outermost side of the laser beam passage range, but instead of this, when the laser beam is made incident at the angle of incidence perpendicular to the workpiece at the innermost side of the laser beam passage range, in a manner opposite to the above embodiment, the hole forming process of making the through hole into a conical shape can be intentionally performed, and the machining of the shape in which the taper is controlled is preferable. Further, by changing the inclination of the laser beam stepwise or continuously during the entire process of the machining or during the machining, the drilling of various hole shapes can be performed. This means that by controlling the inclination of the laser beam, it is possible to perform the drilling process in which the taper state is intentionally controlled.

Examples

(example 1)

In this example, an alumina ceramic plate having a thickness of 0.62mm was subjected to a punching process with a diameter of 200 μm. Specific processing conditions are as follows.

Under the laser condition → 532nm in wavelength, the pulse width is less than 50ps, the repetition frequency is 100kHz, and the output power is 7.5W;

the rotating speed of the light beam rotator is 10000 rpm;

the Z-axis feed pitch was 12 μm.

Fig. 5 is a diagram showing an enlarged image of the through hole obtained by the machining. Fig. 5 (a) is an image of the alumina ceramic plate cut from a cross section of the through hole and viewed from the side of the through hole, and fig. 5 (b) is an image of the surface of the alumina ceramic plate after the cutting.

It can be confirmed from fig. 5 that the through hole having no taper is formed satisfactorily.

(example 2)

In this example, a SiC plate having a thickness of 0.36mm was subjected to a drilling process of 300 μm in diameter. Specific processing conditions are as follows.

Under the laser condition → 532nm in wavelength, less than 15ns in pulse width, 80kHz in repetition frequency and 4.0W in output power;

the rotating speed of the light beam rotator is 5000 rpm;

the Z-axis feed pitch was 20 μm.

Fig. 6 is a diagram showing an enlarged image of the through hole obtained by the machining. Fig. 6 (a) is an image of the SiC plate viewed from the side of the through-hole after the SiC plate is cut by the cross-section passing through the through-hole, and fig. 6 (b) is an image of the SiC plate surface after the through-hole is formed.

It can be confirmed from fig. 6 that the through hole having no taper is formed satisfactorily.

(example 3)

In this example, a Si plate having a thickness of 0.49mm was subjected to a drilling process of 500 μm in diameter. Specific processing conditions are as follows.

Under the laser condition → 532nm in wavelength, less than 15ns in pulse width, 50kHz in repetition frequency and 7.5W in output power;

the rotating speed of the light beam rotator is 5000 rpm;

the Z-axis feed pitch was 60 μm.

Fig. 7 is a diagram showing an enlarged image of the through hole obtained by the machining. Fig. 7 (a) is an image of the Si plate viewed from the side of the through-hole after the Si plate is cut through the cross-section of the through-hole, and fig. 7 (b) is an image of the Si plate surface after the through-hole is formed.

It can be confirmed from FIG. 7 that a through hole having no taper is formed satisfactorily

Description of the reference numerals

10: a radiation source is output;

20: a beam rotator;

21. 22: a prism;

23: a hollow motor;

30: scanning a galvanometer;

40: an f θ lens;

50: a control module;

70: a work table;

100: a processing device;

LB: laser;

f: a light-gathering point;

h: a through hole;

p: processing a predetermined surface;

w: and (5) a workpiece.

Claims

1. A laser processing apparatus for processing a workpiece by irradiating the workpiece with a laser beam, comprising:

an emission source of the laser;

a table on which the workpiece is horizontally placed during machining;

a beam rotator, a scanning galvanometer, and an f θ lens, which are provided on an optical path of the laser beam from the emission source to the workpiece placed on the table in this order from the emission source side; and

a control unit for controlling the operation of each part of the device,

the laser beam having passed through the f θ lens is irradiated from above onto the workpiece,

the beam rotator shifts the laser beam incident thereon to a position parallel to the incident direction and emits the laser beam while rotating the laser beam around the incident direction of the beam rotator as a rotation axis,

the scanning galvanometer is arranged to displace the irradiation position of the laser beam in the workpiece,

the laser light having passed through the beam rotator and the scanning galvanometer passes through the f θ lens, whereby the irradiation direction of the laser light with respect to the irradiation position is rotated while keeping an incident angle thereof with respect to the irradiation position at a prescribed angle,

the control unit synchronizes an operation of displacing the irradiation position of the laser beam along a predetermined closed curve by the scanning galvanometer and an operation of rotating the laser beam in the irradiation direction with respect to the irradiation position by the beam rotator and the f θ lens.

2. Laser processing apparatus according to claim 1,

the laser beam is incident on the workpiece at an incident angle at which the outermost side of the laser beam passing range is perpendicular to the workpiece.

3. Laser processing apparatus according to claim 2,

the control unit synchronizes an operation of the scanning galvanometer rotating the irradiation position of the laser beam by one rotation along a predetermined circle with an operation of rotating the laser beam by one rotation in the irradiation direction with respect to the irradiation position by the beam rotator and the f θ lens.

4. Laser processing apparatus according to claim 3,

the working table is set to be freely lifted,

the control unit moves the table to raise the workpiece every time the irradiation position of the laser beam is displaced by one or more circles along the circle.

5. A beam rotator unit used in an apparatus for processing a workpiece by irradiating the workpiece with laser light, characterized in that,

comprises a beam rotator, a scanning galvanometer, an f theta lens and a control unit for controlling the actions of each part of the beam rotator unit,