Laser processing device and laser processing method

Abstract

The present invention provides a laser processing device and a laser processing method, wherein the laser processing device comprises: a laser oscillator for oscillating a processing laser that is irradiated toward a processing point on a processing surface of a workpiece; a coupling mirror for deflecting or transmitting the processing laser and a measuring light irradiated toward the processing point; a measuring light deflecting unit for changing the incident angle of the measuring light on the coupling mirror; a lens for focusing the processing laser and the measuring light on the processing point; a control unit for controlling the laser oscillator and the measuring light deflecting unit; a measurement processing unit for measuring the depth of a keyhole generated at the processing point by irradiating the processing laser using an optical interference signal based on interference generated by an optical path difference between the measuring light reflected at the processing point and the reference light; and a beam position measuring unit for measuring the positions of the processing laser and the measuring light.

Description

Technical Field

[0001] The present disclosure relates to a laser processing device and a laser processing method. Background Art

[0002] Patent Document 1 discloses a laser processing device. This device uses OCT (Optical Coherence Tomography) technology, which uses an optical interferometer to visualize the internal structure of a sample, to measure the depth of keyholes created by laser processing in metal. The depth of the keyhole can be determined based on an interference signal corresponding to the optical path difference between the measurement light (reflected light) reflected from the bottom surface of the keyhole and the light from the reference branch (reference light).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application No. 2013-501964

[0006] Patent Document 2: Japanese Patent Application No. 2016-538134 Summary of the Invention

[0007] One embodiment of the present disclosure relates to a laser processing device comprising: a laser oscillator for oscillating a processing laser that is irradiated onto a processing point on a processing surface of a workpiece; a coupling mirror for deflecting or transmitting the processing laser and the measurement light irradiated onto the processing point toward the processing point; a measurement light deflection unit for changing the incident angle of the measurement light onto the coupling mirror; a lens for focusing the processing laser and the measurement light onto the processing point; a control unit for controlling the laser oscillator and the measurement light deflection unit; a measurement processing unit for measuring the depth of a keyhole generated at the processing point by irradiating the processing laser using an optical interference signal based on interference generated by an optical path difference between the measurement light reflected at the processing point and the reference light; and a beam position measurement unit for measuring the positions of the processing laser and the measurement light.

[0008] A laser processing method according to one embodiment of the present disclosure is a laser processing method implemented by a laser processing device, wherein the laser processing device comprises a laser emitting portion for emitting laser light toward a workpiece, and a measuring light emitting portion for emitting measuring light for measuring the irradiation position of the laser light in the workpiece, and the laser processing method includes a step of making the irradiation position of the laser light in the workpiece consistent with the irradiation position of the measuring light. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1It is a diagram schematically showing the structure of the laser processing device 1 according to the first embodiment of the present disclosure.

[0010] Figure 2 This is a diagram schematically showing the laser processing apparatus 1 in a state where the first mirror 13 is moved from the origin position.

[0011] Figure 3 1 is a diagram schematically showing the laser processing apparatus 1 in a state where the deviation of the arrival positions of the processing laser light 11 and the measurement light 15 due to chromatic aberration of magnification has been corrected.

[0012] Figure 4 The diagram schematically shows the trajectories of the processing laser light 11 and the measuring light 15 on the processing surface 19 when the surface of the workpiece 18 (processing surface 19) is scanned in a grid pattern by operating only the first mirror 13 without operating the measuring light deflecting unit 17.

[0013] Figure 5 1 is a diagram showing a configuration example of the beam position measuring unit 38 used to calculate the correction amount at the processing light lattice points 30 .

[0014] Figure 6 This is a flowchart for explaining a method of calculating the correction amount at the processing light lattice point 30 .

[0015] Figure 7 39 is a diagram showing a configuration example of a light beam position measuring unit 38 including two position measuring mirrors 39 a and 39 b .

[0016] Figure 8 This is a flowchart showing a method for creating correction table data.

[0017] Figure 9 This is a diagram showing an example of data items included in the corrected processed data.

[0018] Figure 10 This is a flowchart for explaining a method for creating corrected processed data.

[0019] Figure 11 1 is a diagram showing a machining point position correction table 34 schematically showing the structure of the machining point position correction table data.

[0020] Figure 12 This is a flowchart showing a method for setting the correction amount.

[0021] Figure 13 The scanning angle X and Figure 11The correction table 34 for machining point positions shows a relationship between the scan angle X and the surrounding correction data points when the correction table uses scan angles for any data point 32 does not match.

[0022] Figure 14 This is a flowchart for explaining a laser processing method performed by the laser processing apparatus 1 according to the first embodiment of the present disclosure.

[0023] Figure 15 This is a flowchart for explaining a method for measuring the depth of the keyhole 22 .

[0024] Figure 16 This is a diagram illustrating the trajectories of the processing laser light 11 and the measurement light 15 on the processing surface 19 in a state where the influence of magnification chromatic aberration is corrected by operating the measurement light deflection unit 17 .

[0025] Figure 17 It is a diagram schematically showing the configuration of a laser processing apparatus 1 according to a first modification example of the present disclosure.

[0026] Figure 18 It is a diagram schematically showing the configuration of a laser processing apparatus 1 according to a second modification of the present disclosure.

[0027] Figure 19 This is a schematic diagram showing a laser processing apparatus according to a second embodiment of the present disclosure.

[0028] Figure 20 This is a diagram showing a state in which the beam position measuring unit derives the relative position of the optical axis of the measurement light with respect to the optical axis of the processing light.

[0029] Figure 21 It is a flowchart of the program executed by the control device.

[0030] Figure 22 It is a diagram showing the irradiation position of the processing light and the irradiation position of the measurement light on the imaging element in the first optical adjustment.

[0031] Figure 23 It is a diagram showing the irradiation position of the processing light and the irradiation position of the measurement light on the imaging element in the second and subsequent optical adjustments.

[0032] Figure 24 This is a diagram showing a state in which optical adjustments are performed for the second and subsequent times in the laser processing apparatus according to the modified example of the second embodiment of the present disclosure.

[0033] Figure 25 This is a diagram showing a state in which optical adjustments have been performed for the first and subsequent times in the laser processing apparatus according to the modified example of the second embodiment of the present disclosure.

[0034] Explanation of symbols

[0035] 1. Laser processing device;

[0036] 2 processing head;

[0037] 3. Optical interferometer;

[0038] 4. Measurement and processing department;

[0039] 5. Laser oscillator;

[0040] 6. Control Department;

[0041] 7 1st drive;

[0042] 8 2nd drive;

[0043] 9. Determine the light guide inlet;

[0044] 10 Processing light guide inlet;

[0045] 11. Laser processing;

[0046] 12 dichroic mirrors;

[0047] 13 Mirror 1;

[0048] 14 lenses;

[0049] 15 Determination of light;

[0050] 16 collimating lens;

[0051] 17. Measurement light deflection unit;

[0052] 18. Workpiece;

[0053] 19 machining surface;

[0054] 20 processing points;

[0055] 21 molten pool;

[0056] 22 key holes;

[0057] 23 Determination of optical axis;

[0058] 24 machining optical axis;

[0059] 25 lens optical axis;

[0060] 26 machining origin;

[0061] 27 Determine light trajectory;

[0062] 28 processing light track;

[0063] 29 Determination of light grid points;

[0064] 30 processing light grid points;

[0065] 31 memory;

[0066] 32 data points;

[0067] 33 corrected data points;

[0068] 34 Correction table of processing point positions;

[0069] 35 Mirror 2;

[0070] 36 mobile workbench;

[0071] 37 workbench drive;

[0072] 38. beam position determination unit;

[0073] 39 position measuring mirror;

[0074] 40 two-dimensional imaging element;

[0075] 41 Beam terminator. DETAILED DESCRIPTION

[0076] The preferred embodiments of the present disclosure are described in detail below with reference to the accompanying drawings. In addition, in this specification and the accompanying drawings, components having substantially the same functions are denoted by the same reference numerals, thereby omitting repeated descriptions. Figure 1 Hereinafter, the x-axis direction, the y-axis direction, and the z-axis direction respectively represent the direction parallel to the x-axis, the direction parallel to the y-axis, and the direction parallel to the z-axis. The x-axis direction and the y-axis direction are orthogonal to each other. The x-axis direction and the z-axis direction are orthogonal to each other. The y-axis direction and the z-axis direction are orthogonal to each other. The xy plane represents a virtual plane parallel to the x-axis direction and the y-axis direction. The xz plane represents a virtual plane parallel to the x-axis direction and the z-axis direction. The yz plane represents a virtual plane parallel to the y-axis direction and the z-axis direction. In addition, in Figure 1 Hereinafter, in the x-axis direction, the direction indicated by the arrow is referred to as the positive x-axis direction, and the direction opposite to the arrow is referred to as the negative x-axis direction. Figure 1 Hereinafter, in the y-axis direction, the direction indicated by the arrow is referred to as the positive y-axis direction, and the direction opposite to the arrow is referred to as the negative y-axis direction. Figure 1 Hereinafter, the z-axis direction is the positive z-axis direction, and the direction opposite to the positive z-axis direction is the negative z-axis direction. The z-axis direction is, for example, the vertical direction or the up-down direction, and the x-axis and y-axis directions are, for example, the horizontal direction or the left-right direction.

[0077] (Implementation Method 1)

[0078] In recent years, laser processing devices combining a galvanometer mirror and an fθ lens have become known. A galvanometer mirror is a mirror capable of finely controlling the direction in which laser light is reflected. The fθ lens focuses the laser light at a processing point on the surface of the workpiece. However, applying the method for measuring keyhole depth disclosed in Patent Document 1 to a laser processing device combining a galvanometer mirror and an fθ lens presents the following problems. Specifically, the wavelengths of the processing laser light and the measurement light differ, and the fθ lens has the characteristic of producing chromatic aberration. Consequently, the processing laser light and the measurement light are offset on the surface of the workpiece, making it impossible to accurately measure the keyhole depth.

[0079] An object of one aspect of the present disclosure is to provide a laser processing apparatus and a laser processing method capable of accurately measuring the depth of a keyhole.

[0080] Non-limiting embodiments of the present disclosure contribute to providing a laser processing apparatus and a laser processing method capable of accurately measuring the depth of a keyhole.

[0081] One embodiment of the present disclosure relates to a laser processing device comprising: a laser oscillator for oscillating a processing laser that is irradiated onto a processing point on a processing surface of a workpiece; a coupling mirror for deflecting or transmitting the processing laser and the measuring light irradiated onto the processing point toward the processing point; a measuring light deflecting unit for changing the incident angle of the measuring light onto the coupling mirror; a lens for focusing the processing laser and the measuring light onto the processing point; a control unit for controlling the laser oscillator and the measuring light deflecting unit; a measurement processing unit for measuring the depth of a keyhole generated at the processing point by irradiating the processing laser using an optical interference signal based on interference generated due to an optical path difference between the measuring light reflected at the processing point and the reference light; and a beam position measuring unit for measuring the positions of the processing laser and the measuring light.

[0082] A laser processing method according to an embodiment of the present disclosure is a laser processing method performed by a laser processing device, the laser processing device comprising: a first mirror for changing the traveling directions of a processing laser and a measurement light; a measurement light deflection unit for changing the incident angle of the measurement light on the first mirror; and a lens for focusing the processing laser and the measurement light on a processing point on a processing surface of a workpiece, the laser processing device measuring the depth of a keyhole produced at the processing point by irradiating the processing laser. The laser processing method includes: a step of setting a target position on the processing surface; a step of setting a first instruction value indicating an amount of movement of the first mirror for causing the processing laser to reach the target position; a step of determining a second instruction value indicating an amount of movement of the measurement light deflection unit based on the positions of the processing laser and the measurement light measured by a beam position measurement unit for measuring the positions of the processing laser and the measurement light; and a step of controlling a laser oscillator that oscillates the processing laser, the first mirror, and the measurement light deflection unit based on processing data including the first instruction value and the second instruction value.

[0083] According to one embodiment of the present disclosure, it is possible to configure a laser processing apparatus and a laser processing method that can accurately measure the depth of a keyhole.

[0084] Further advantages and effects of an embodiment of the present disclosure may become apparent from the description and accompanying drawings. The corresponding advantages and / or effects are provided by the features described in several embodiments and the description and accompanying drawings, but it is not necessary to provide all features in order to obtain one or more of the same features.

[0085] The processing data may include a first instruction value indicating the amount of movement of the first mirror and a second instruction value indicating the amount of movement of the measurement light deflecting unit. The beam position measuring unit may include a position measuring mirror for reflecting the processing laser light and the measurement light that have passed through a lens, and a two-dimensional imaging element for measuring the positions of the processing laser light and the measurement light reflected by the position measuring mirror. The control unit may set a target position on the processing surface, set the first instruction value for causing the processing laser light to reach the target position, and calculate the second instruction value based on the positions of the processing laser light and the measurement light measured by the two-dimensional imaging element.

[0086] The position measuring mirror may be set to have a reflectivity of a wavelength of the processing laser light such that the processing laser light has a power that can be input to the two-dimensional imaging element. The two-dimensional imaging element may be disposed at a position where the optical path length from the lens to the two-dimensional imaging element coincides with the optical path length from the lens to the processing point.

[0087] The position measuring mirror may be composed of a plurality of mirrors.

[0088] The reflectivity of the position measuring mirror at the wavelength of the processing laser light may be 0.1% or less.

[0089] The control unit may set a grid pattern on the processing surface and set grid points of the grid pattern as target positions.

[0090] <Structure of Laser Processing Device 1>

[0091] Reference Figure 1 The structure of the laser processing apparatus 1 according to the first embodiment of the present disclosure will be described. Figure 1 It is a diagram schematically showing the structure of the laser processing device 1 according to the first embodiment of the present disclosure.

[0092] The laser processing apparatus 1 includes a processing head 2 , an optical interferometer 3 , a measurement processing unit 4 , a laser oscillator 5 , a control unit 6 , a first driver 7 , and a second driver 8 .

[0093] The optical interferometer 3 emits measurement light 15 for OCT measurement. The measurement light 15 emitted from the optical interferometer 3 is input to the processing head 2 via the measurement light inlet 9. The measurement light inlet 9 is provided on the measurement light deflection unit 17. The measurement light inlet 9 is provided on the processing head 2 at a position capable of introducing the measurement light 15 into the measurement light deflection unit 17.

[0094] The laser oscillator 5 oscillates a processing laser beam 11 for laser processing. The processing laser beam 11 oscillated from the laser oscillator 5 is input to the processing head 2 through the processing light introduction port 10 .

[0095] The machining laser light 11 input to the machining head 2 passes through the dichroic mirror 12 , is reflected by the first mirror 13 , passes through the lens 14 , and is focused onto the surface of the workpiece 18 , ie, the machining surface 19 .

[0096] Thus, the processing point 20 of the workpiece 18 is laser processed. At this time, the processing point 20 irradiated with the processing laser light 11 melts, and a molten pool 21 is formed in the workpiece 18.

[0097] Furthermore, the molten metal evaporates from the molten pool 21 , and the keyhole 22 is formed in the workpiece 18 due to the pressure of the vapor generated during the evaporation.

[0098] The measurement light 15 input from the measurement light inlet 9 to the machining head 2 is converted into parallel light by the collimating lens 16 and reflected by the measurement light deflection unit 17. The measurement light 15 is then reflected by the dichroic mirror 12, then by the first mirror 13, and is then focused by the lens 14 onto a machining point 20 on a machining surface 19 of a workpiece 18. The dichroic mirror 12 is a coupling mirror that couples the measurement light 15 to the machining laser light 11.

[0099] The measuring light 15 is then reflected by the bottom surface of the keyhole 22, traveling in the opposite direction of the propagation path, and reaches the optical interferometer 3. The optical interferometer 3 generates an optical interference signal due to optical interference between the input measuring light 15 and reference light (not shown). The reference light is light emitted from a light source (not shown) of the optical interferometer 3 and directed toward a reference mirror (not shown), which is a reference surface.

[0100] The measurement processing unit 4 measures the depth of the keyhole 22, that is, the penetration depth of the processing point 20, based on the optical interference signal. The penetration depth refers to the distance between the topmost point of the melted portion of the workpiece 18 and the processing surface 19.

[0101] The wavelength (first wavelength) of the processing laser light 11 is different from the wavelength (second wavelength) of the measuring light 15. The dichroic mirror 12 has a characteristic of transmitting the light of the first wavelength and reflecting the light of the second wavelength.

[0102] For example, when a YAG laser or a fiber laser is used as the processing laser 11, the wavelength of the processing laser 11 is 1064 nm. Furthermore, for example, when an OCT light source is used as the measurement light 15, the wavelength of the measurement light 15 is 1300 nm.

[0103] The first mirror 13 and the measurement light deflection unit 17 are movable mirrors that can rotate about two or more axes. The first mirror 13 and the measurement light deflection unit 17 are, for example, galvanometer mirrors.

[0104] The first mirror 13 is connected to the control unit 6 via the first driver 7 . The measurement light deflection unit 17 is connected to the control unit 6 via the second driver 8 .

[0105] The first driver 7 operates the first mirror 13 based on an instruction from the control unit 6 . The second driver 8 operates the measurement light deflection unit 17 based on an instruction from the control unit 6 .

[0106] The control unit 6 includes a memory 31. The memory 31 stores processing data and correction table data for performing desired processing on the workpiece 18. The correction table data will be described in detail later.

[0107] exist Figure 1 1 and 2 , as examples, only the rotational motions about the rotational axis extending in the y-axis direction are shown for the first mirror 13 and the measuring light deflecting unit 17. The rotational motions are indicated by the square dotted lines and double-headed arrow lines in the figure.

[0108] Furthermore, the first mirror 13 and the measurement light deflection unit 17 may each be configured to be rotatable about two or more axes. In such a configuration, the first mirror 13 and the measurement light deflection unit 17 may each be configured to be rotatable about a rotation axis extending in the x-axis direction.

[0109] In the following, for simplicity of description, a case will be described in which the first mirror 13 and the measurement light deflecting unit 17 each perform a rotation operation around a rotation axis extending in the y-axis direction.

[0110] When the measurement light deflecting unit 17 is at the origin position, the measurement optical axis 23 of the measurement light 15 is reflected by the dichroic mirror 12 and then coincides with the processing optical axis 24 of the processing laser light 11 .

[0111] When the first mirror 13 is at the origin, the processing optical axis 24 of the processing laser light 11 is reflected by the first mirror 13 and then passes through the lens 14 , coinciding with the center of the lens 14 , that is, the lens optical axis 25 .

[0112] In the following description, the position where the processing laser light 11 and the measuring light 15 that have passed through the center of the lens 14 reach the processing surface 19 of the workpiece 18 (which may also be referred to as the irradiation position) is referred to as the "processing origin 26" (see Figure 2 ).

[0113] The origin positions of the first mirror 13 and the measurement light deflecting unit 17 are equal to the positions of the centers of the processing laser light 11 and the measurement light 15 passing through the lens 14 .

[0114] The lens 14 is a lens for converging the processing laser light 11 and the measurement light 15 on the processing point 20. The lens 14 is, for example, an fθ lens.

[0115] The first mirror 13 and the lens 14 constitute a general optical scanning system formed of a galvanometer mirror and an fθ lens.

[0116] Therefore, by rotating the first mirror 13 by a predetermined angle from its origin position, the arrival position of the processing laser light 11 on the processing surface 19 can be controlled.

[0117] Hereinafter, the angle by which the first mirror 13 is rotated from its origin position is referred to as “the movement amount of the first mirror 13 ”.

[0118] Furthermore, if the positional relationship of the optical components constituting the machining head 2 and the distance from the lens 14 to the machining surface 19 can be determined, the movement amount of the first mirror 13 for irradiating the machining laser beam 11 to the desired machining point 20 can be uniquely set.

[0119] The distance from the lens 14 to the processing surface 19 is preferably set so that the focal position of the processing laser 11, where the laser beam is most focused, coincides with the processing surface 19, thereby enabling the most efficient processing by the processing laser 11. However, the distance from the lens 14 to the processing surface 19 is not limited to this and may be any distance determined according to the processing application.

[0120] By changing the movement amount of the first mirror 13 in a predetermined movement schedule, the position of the processing point 20 can be scanned on the processing surface 19 .

[0121] Furthermore, by switching the laser oscillator 5 on and off under the control of the control unit 6 , it is possible to laser process any position on the processing surface 19 within the scannable range of the processing laser light 11 in any pattern.

[0122] <Influence caused by chromatic aberration>

[0123] Next, use Figure 2 The influence of chromatic aberration is explained. Figure 2 Schematically shows the laser processing device 1 in a state where the first mirror 13 is moved from the origin position. Figure 2 In FIG, it is assumed that the measuring light deflecting unit 17 is at the origin position.

[0124] like Figure 2 As shown, the processing laser light 11 and the measuring light 15 reflected by the first mirror 13 travel on the same optical axis until reaching the lens 14. However, after passing through the lens 14, the processing laser light 11 and the measuring light 15 are offset in their traveling directions.

[0125] That is, Figure 2 As shown, the position of the machining optical axis 24a, which is the optical axis of the machining laser light 11, is offset from the position of the measurement optical axis 23a, which is the optical axis of the measurement light 15. Therefore, the measurement light 15 reaches a position different from the position of the machining point 20.

[0126] This is caused by chromatic aberration of the lens 14. Chromatic aberration refers to an aberration caused by the property of general optical materials including the lens 14 that the refractive index varies depending on the wavelength of light.

[0127] There are two types of chromatic aberration: axial chromatic aberration and lateral chromatic aberration. Axial chromatic aberration refers to the property that the focal position of a lens varies depending on the wavelength of light.

[0128] On the other hand, chromatic aberration of magnification refers to a property in which the image height on the focal plane differs depending on the wavelength of light.

[0129] Figure 2 The deviation between the traveling direction of the processing laser light 11 (processing optical axis 24 a ) and the traveling direction of the measurement light 15 (measurement optical axis 23 a ) transmitted through the lens 14 is caused by the aforementioned chromatic aberration of magnification.

[0130] The laser processing apparatus 1 of this embodiment also experiences the aforementioned axial chromatic aberration. However, the misalignment between the travel directions of the processing laser light 11 and the travel directions of the measurement light 15 caused by axial chromatic aberration can be addressed as follows. Specifically, the distance between the collimating lens 16 and the measurement light inlet 9 can be adjusted so that the measurement light 15 immediately after passing through the collimating lens 16 is either slightly divergent or slightly convergent compared to a parallel state.

[0131] exist Figure 2 In FIG. 2 , the distance from the position where the measuring light 15 reaches the processing surface 19 to the processing origin 26 is longer than the distance from the position where the processing laser light 11 reaches the processing surface 19 to the processing origin 26 .

[0132] However, due to the lens structure of lens 14 and the relationship between the wavelengths of processing laser light 11 and measurement light 15, the distance of the former may be shorter than the distance of the latter. In addition, generally, long-wavelength light reaches a position farther from processing origin 26 than short-wavelength light.

[0133] One method for correcting chromatic aberration of magnification is to give lens 14 the properties of an achromatic lens. However, giving lens 14 both the properties of an fθ lens and an achromatic lens requires highly advanced optical design technology, and designing lens 14 is time-consuming and costly.

[0134] Therefore, in this embodiment, as described below, chromatic aberration of magnification is corrected at low cost by operating the measurement light deflection unit 17. In the following description, the deflection unit that changes the angle of the measurement optical axis 23 is referred to as the "measurement light deflection unit." The measurement light deflection unit 17 of this embodiment is an example of a measurement light deflection unit.

[0135] <How to Correct Chromatic Aberration of Magnification>

[0136] Next, use Figure 3 The method of correcting chromatic aberration of magnification is described. Figure 3 1 is a diagram schematically showing the laser processing apparatus 1 in a state where the deviation of the arrival positions of the processing laser light 11 and the measurement light 15 due to chromatic aberration of magnification has been corrected.

[0137] exist Figure 3 In the process, the measuring light deflection unit 17 is moved from the origin position by a predetermined movement amount (also called movement angle). Figure 3 As shown, between the dichroic mirror 12 and the lens 14 , the processing optical axis 24 of the processing laser light 11 and the measurement optical axis 23 of the measurement light 15 are not arranged coaxially.

[0138] However, the processing laser light 11 and the measuring light 15 respectively pass through the lens 14 and then reach the same position on the processing surface 19 , that is, the processing point 20 .

[0139] exist Figure 3 In the process, the processing optical axis 24a of the processing laser 11 passes through Figure 2 On the other hand, in the same position as the processing optical axis 24a shown. Figure 3 The measurement light axis 23b of the measurement light 15 corrected by the operation of the measurement light deflection unit 17 passes through the Figure 2 The measurement optical axis 23a is shown at different positions.

[0140] The amount of movement of the measurement light deflection unit 17 (that is, the angle by which the measurement light deflection unit 17 is rotated from its origin position) and the amount of movement of the first mirror 13 are associated one-to-one.

[0141] The amount of movement of the first mirror 13 is uniquely determined by the position of the processed point 20 , and therefore the amount of movement of the measurement light deflection unit 17 is also uniquely determined by the position of the processed point 20 .

[0142] In addition, hereinafter, the operation amount of the measurement light deflection unit 17 is referred to as a “correction amount”.

[0143] <Relationship between Correction Amount and Scan Angle>

[0144] Next, the relationship between the correction amount and the scan angle will be described.

[0145] In the fθ lens, i.e., lens 14, when the focal length of lens 14 is set to f, the angle of the light incident on lens 14 from the lens optical axis 25 is set to θ, and the distance of the light passing through lens 14 from the optical axis (lens optical axis 25) on the image plane (processing surface 19) (hereinafter referred to as image height) is set to h, the relationship h=fθ holds.

[0146] As described above, the first mirror 13 has two axes for rotation. These two axes are assumed to be the x-axis and the y-axis, and the angle of the x-axis component of the light reflected by the first mirror 13 from the lens optical axis 25 is denoted as θx. Similarly, the angle of the y-axis component of the light reflected by the first mirror 13 from the lens optical axis 25 is denoted as θy.

[0147] Furthermore, when the image heights in the x direction and the y direction on the image plane of the light beam that has passed through the lens 14 are respectively represented by x and y, the relationship x=fθx and y=fθy holds.

[0148] Therefore, if the position where the processing laser light 11 reaches the processing surface 19 is defined as (x, y), then (x, y)=(fθx, fθy).

[0149] Furthermore, the emission angle of the reflected light reflected from the mirror 13 after the light enters the mirror 13 is changed by an angle twice the amount of movement of the first mirror 13 .

[0150] Therefore, when the movement amount of the first mirror 13 is set to In the case of In the following description, the movement amount of the first mirror 13 is It is called the "scan angle".

[0151] Thus, in the laser processing apparatus 1 of this embodiment, if the scanning angle of the first mirror 13 can be determined Then, the position (x, y) of the processing point 20 , which is the arrival position of the processing laser light 11 on the processing surface 19 , can also be determined.

[0152] As described above, the scanning angle can be uniquely determined according to the position of the processing point 20 . Similarly, the correction amount can also be uniquely determined according to the position of the processing point 20 .

[0153] Therefore, data (correction table data) for correcting the offset of the measurement light 15 caused by magnification chromatic aberration is calculated in advance. The laser processing apparatus 1 of this embodiment uses this correction table data when processing the workpiece 18, thereby operating the measurement light deflection unit 17 by a correction amount corresponding to the position of the processing point 20. The correction table data is data that indicates the correspondence between the scanning angle and the correction amount for each processing point 20.

[0154] <Details of Correction Table Data>

[0155] Below, refer to Figure 4 The following describes the respective trajectories of the processing laser light 11 and the measurement light 15 on the processing surface 19 , which are prerequisites for calculating the correction amount.

[0156] Figure 4 The diagram schematically shows the trajectories of the processing laser light 11 and the measuring light 15 on the processing surface 19 when the surface of the workpiece 18 (processing surface 19) is scanned in a grid pattern by operating only the first mirror 13 without operating the measuring light deflecting unit 17.

[0157] exist Figure 4 ] shows a state where the processed surface 19 is viewed from the lens 14 side. Figure 4 The orthogonal grid pattern of solid lines represents the trajectory of the processing laser light 11 (processing light trajectory 28 ). Figure 4 The orthogonal grid pattern of dotted lines represents the trajectory of the measurement light 15 (measurement light trajectory 27 ).

[0158] These orthogonal grid patterns are loci when the surface of the workpiece 18 (processing surface 19 ) is scanned in a grid pattern by operating only the first mirror 13 without operating the measurement light deflecting unit 17 .

[0159] exist Figure 4 In the example shown, since the measuring light deflection unit 17 is not in operation, the correction of magnification chromatic aberration is not performed. Figures 1 to 3 In the vicinity of the processing origin 26 shown, the trajectories of the processing laser light 11 and the measurement light 15 coincide with each other, but the deviation between them increases as the distance from the processing origin 26 increases.

[0160] As a result, the processing light trajectory 28 draws an orthogonal grid pattern without distortion, while the measurement light trajectory 27 draws a distorted linear trajectory.

[0161] in addition, Figure 4 The distortion shape of the measurement light trajectory 27 shown can be changed according to the optical characteristics of the lens 14 .

[0162] Furthermore, the amount of deviation between the positions corresponding to the processing light trajectory 28 and the measurement light trajectory 27 also depends on the optical characteristics and optical design of the lens 14 .

[0163] As a general example, in a commercially available fθ lens having a focal length of 250 mm and a processed surface area with a diameter of approximately 200 mm, a deviation of 0.2 mm to 0.4 mm occurs near the outermost periphery of the processed surface area.

[0164] On the other hand, the keyhole 22 (for example, see Figure 1 ) is relatively small, roughly 0.03mm to 0.2mm, although its diameter depends on the power and quality of the processing laser.

[0165] Therefore, due to the positional deviation between the machining laser light 11 and the measuring light 15 caused by the chromatic aberration of the lens 14 , the measuring light 15 does not reach the bottom surface of the keyhole 22 , and accurate penetration cannot be measured.

[0166] In addition, Figure 4 In the figure, an orthogonal grid pattern of 4×4 squares at equal intervals is exemplified, but the shape of the grid pattern is not limited thereto.

[0167] For example, the number of grids in the orthogonal grid pattern may be increased, or the intervals between the grids in a region requiring particularly high precision may be narrowed in conjunction with the lateral chromatic aberration characteristics of the fθ lens.

[0168] In addition, a radial grid pattern may be set instead of the orthogonal grid pattern. However, in this embodiment, the correction amount is set by two axes, the x-axis and the y-axis, so the orthogonal grid pattern is more preferable.

[0169] If Figure 4 Comparing the processing light trajectory 28 and the measurement light trajectory 27 shown, it can be seen that the corresponding grid points on their respective orthogonal grid patterns are offset. In other words, it can be seen that a processing light grid point 30 at a specific location on the processing light trajectory 28 is offset from the corresponding measurement light grid point 29 on the measurement light trajectory 27.

[0170] In order to create the correction table data, it is necessary to calculate the correction amount so that a processing light grid point 30 at a specific location on the processing light trajectory 28 and a corresponding measurement light grid point 29 on the measurement light trajectory 27 are consistent (the grid points of the grid pattern are set as target positions).

[0171] <Calculation Method of Correction Amount>

[0172] Next, a method of calculating the correction amount at the processing light lattice point 30 will be described. Figure 5 1 is a diagram showing a configuration example of the beam position measuring unit 38 used to calculate the correction amount at the processing light lattice points 30 .

[0173] The beam position measuring unit 38 is provided between the lens 14 and the workpiece 18. The beam position measuring unit 38 includes a position measuring mirror 39, a two-dimensional imaging element 40, and a beam terminator 41.

[0174] The position measuring mirror 39 has a function of attenuating the power of the processing laser light 11 , and has a characteristic of separating light of the wavelength of the processing laser light 11 into reflected light and transmitted light, and reflecting light of the wavelength of the measuring light 15 .

[0175] The reflectivity of the position measuring mirror 39 at the wavelength of the processing laser light 11 is set so that the power of the reflected processing laser light 11 is approximately the same as the power of the reflected measuring light 15 .

[0176] For example, when a fiber laser with a rated output of 1 kW or more, which is used in general processing, is selected as the processing laser 11 , the minimum power that can be output by the processing laser 11 is approximately 100 W.

[0177] In contrast, the output of an OCT light source is several tens of mW when used as the measurement light 15. Therefore, in order to reduce the output of the 100-W processing laser light 11 to the same level (several tens of mW) as the measurement light 15 of several tens of mW, it is preferable to set the reflectivity of the position measuring mirror 39 at the wavelength of the processing laser light 11 to 0.1% or less.

[0178] On the other hand, since the measurement light 15 does not need to be attenuated, the reflectivity of the position measuring mirror 39 at the wavelength of the measurement light 15 is preferably set to 90% or more.

[0179] The two-dimensional imaging element 40 has the function of measuring the positions of the processing laser light 11 and the measurement light 15. The two-dimensional imaging element 40 only needs to be sensitive to the wavelengths of the processing laser light 11 and the measurement light 15. Commercially available industrial cameras and two-dimensional beam profilers using elements such as CCDs (charge-coupled devices), CMOSs (complementary metal oxide semiconductors), and InGaAs (indium gallium arsenide) can be used.

[0180] The beam terminator 41 has a function of terminating the processing laser light 11 that has passed through the position measuring mirror 39 .

[0181] The processing laser light 11 and the measuring light 15 transmitted through the lens 14 are separated into the processing laser light 11 a and the measuring light 15 a reflected by the position measuring mirror 39 , and the processing laser light 11 b transmitted through the position measuring mirror 39 .

[0182] The processing laser light 11 b that has passed through the position measuring mirror 39 is stopped by the beam terminator 41 .

[0183] On the other hand, the processing laser light 11a and the measuring light 15a reflected by the position measuring mirror 39 are input to the two-dimensional imaging element 40. The two-dimensional imaging element 40 measures the positions of the input processing laser light 11a and the measuring light 15a.

[0184] In the section from the lens 14 to the two-dimensional imaging element 40 , no optical element for transmitting light is arranged, and only the light reflected by the position measuring mirror 39 can be transmitted.

[0185] The optical path lengths of the processing laser light 11 and the measurement light 15 from the lens 14 to the two-dimensional imaging element 40 match the optical path length from the lens 14 to the processing point 20 when the beam position measuring unit 38 is not provided.

[0186] Therefore, the relative positional relationship of the measurement light 15 with respect to the position of the processing laser 11 measured by the two-dimensional imaging element 40 is consistent with the positional relationship between the processing laser 11 and the measurement light 15 at the processing point 20 when the beam position measuring unit 38 is not provided.

[0187] Figure 6 This is a flowchart for explaining a method of calculating the correction amount at the processing light lattice point 30 .

[0188] In step S1, the beam position measuring unit 38 is installed at the processing light grid point 30 where the correction amount is to be calculated. At this time, the two-dimensional imaging element 40 is installed at a position such that the optical path length from the lens 14 to the two-dimensional imaging element 40 is the same as the optical path length from the lens 14 to the processing point 20 when the beam position measuring unit 38 is not installed.

[0189] In step S2 , the scanning angle of the first mirror 13 is set so that the processing laser light 11 reaches the processing light lattice point 30 for determining the correction amount.

[0190] In step S3 , the processing laser beam 11 is irradiated, and the arrival position of the processing laser beam 11 at the two-dimensional imaging element 40 is determined by the beam position measuring unit 38 .

[0191] At this time, the output of the processing laser light 11 during irradiation is preferably set to an output that is 10% or more of the rated output of the laser oscillator 5. This is because, particularly when the laser oscillator 5 is a fiber laser, if the output is set to less than 10% of the rated output, the oscillation state of the laser light may become unstable, making it impossible to accurately measure the arrival position of the processing laser light 11 at the two-dimensional imaging element 40.

[0192] In step S4 , the measuring light 15 is irradiated, and the arrival position of the measuring light 15 at the two-dimensional imaging element 40 is determined by the light beam position measuring unit 38 .

[0193] In step S5, a correction amount for the measurement light deflection unit 17 is calculated while referring to the measurement results of the two-dimensional imaging element 40 of the beam position measurement unit 38 so that the arrival position of the processing laser light 11 determined in step S3 coincides with the arrival position of the measurement light 15. The correction amount is calculated by the control unit 6, for example.

[0194] The method described above can calculate the correction amount at the processing light grid point 30. By calculating the correction amount, the output of the processing laser light 11 input to the two-dimensional imaging element 40 can be made close to the output of the measurement light 15, so that the same two-dimensional imaging element 40 can be used.

[0195] Generally, when measuring the position of laser beams having a large output difference using the two-dimensional imaging element 40 , it is necessary to use a different two-dimensional imaging element 40 according to the output.

[0196] On the other hand, the above-described method for calculating the correction amount eliminates the need to replace the two-dimensional imaging element 40 when measuring the arrival positions of the processing laser light 11 and the measurement light 15, thereby eliminating any installation errors associated with the two-dimensional imaging element 40. Consequently, the arrival positions of the processing laser light 11 and the measurement light 15 can be determined with high accuracy.

[0197] Furthermore, since the optical path from lens 14 to 2D imaging element 40 includes only reflected light, not light passing through optical components, it is not affected by refraction or chromatic aberration of glass materials. Therefore, the arrival positions of machining laser light 11 and measurement light 15 can be determined with high accuracy.

[0198] In addition, for Figure 5 Although the illustrated beam position measuring unit 38 uses one position measuring mirror 39 , the number of the position measuring mirrors 39 is not limited to one, and may be two or more.

[0199] Figure 7 39 is a diagram showing a configuration example of a light beam position measuring unit 38 including two position measuring mirrors 39 a and 39 b .

[0200] The two position measuring mirrors 39a and 39b are arranged in parallel and spaced apart from each other in the x-axis direction.

[0201] The processing laser light 11 and the measuring light 15 are separated into the processing laser light 11 a and the measuring light 15 a reflected by the position measuring mirror 39 a , and the processing laser light 11 c transmitted through the position measuring mirror 39 a .

[0202] The processing laser light 11 a is divided into the processing laser light 11 b reflected by the position measuring mirror 39 b and the processing laser light 11 d transmitted through the position measuring mirror 39 b . The processing laser light 11 b is input to the two-dimensional imaging element 40 .

[0203] The measurement light 15 a is input to the two-dimensional imaging element 40 as the measurement light 15 b reflected by the position measuring mirror 39 b .

[0204] At this time, the optical path from the position measuring mirror 39 a to the two-dimensional imaging element 40 does not include an optical path that passes through optical components but includes only an optical path where light is reflected.

[0205] The two-dimensional imaging element 40 is provided at a position where the optical path length from the lens 14 to the two-dimensional imaging element 40 matches the optical path length from the lens 14 to the processing point 20 when the beam position measuring unit 38 is not provided.

[0206] The processing laser light 11 c that has passed through the position measuring mirror 39 a is stopped by the beam terminator 41 a .

[0207] The processing laser light 11d having passed through the position measuring mirror 39b is stopped by the beam terminator 41b.

[0208] By combining the plurality of position measuring mirrors 39 a and 39 b in this manner, the powers of the processing laser light 11 and the measuring light 15 reaching the two-dimensional imaging element 40 can be adjusted to be of the same level.

[0209] in addition, Figure 5 as well as Figure 7 The illustrated beam position measuring unit 38 includes a position measuring mirror 39 as an optical element for reflecting the processing laser light 11 and the measuring light 15. However, a total reflection mirror may be combined with the position measuring mirror 39. Even when a total reflection mirror is combined, the optical path from the lens 14 to the two-dimensional imaging element 40 does not include an optical path that passes through optical components but only includes an optical path where light is reflected.

[0210] in addition, Figure 5 as well as Figure 7 The shape of the position measuring mirror 39 shown is not limited to a flat plate shape, and the position measuring mirror 39 may be any shape as long as the reflection surface for the processing laser light 11 and the measurement light 15 is a flat reflection surface.

[0211] in addition, Figure 5 as well as Figure 7 The beam position measuring unit 38 shown has the beam terminator 41 , but may be configured without the beam terminator 41 if there is no problem in terms of safety.

[0212] In addition, Figure 5 In FIG. 1 , the workpiece 18 is illustrated for convenience of explanation. However, the workpiece 18 is not used in the calculation of the correction amount described above, and thus illustration of the workpiece 18 may be omitted.

[0213] Furthermore, the angles of the optical axes of the processing laser light 11 and the measurement light 15 incident on the beam position measuring unit 38 vary depending on the positions of the processing light grid points 30. Therefore, the beam position measuring unit 38 may further include a mechanism for adjusting the angle of the position measuring mirror 39 and a mechanism for adjusting the position of the two-dimensional imaging element 40 so that the processing laser light 11 and the measurement light 15 are input to the two-dimensional imaging element 40.

[0214] The beam position measuring unit 38 functions as the laser processing apparatus 1 and may be a unit incorporated into the laser processing apparatus 1 or a unit other than the laser processing apparatus 1 .

[0215] When the beam position measuring unit 38 is assembled into the laser processing device 1, it can also be configured such that the two-dimensional imaging element 40 is connected to the control unit 6, and based on the measurement results of the two-dimensional imaging element 40, the control unit 6 controls the measurement light deflection unit 17, and the control unit 6 calculates the correction amount of the measurement light deflection unit 17.

[0216] The above-described method of calculating the correction amount is suitable for a case where a laser having excellent beam quality (for example, a single-mode fiber laser) is used in the machining head 2 .

[0217] This is because, in a single-mode fiber laser, the beam diameter at the processing point 20 of the processing laser 11 becomes less than 50 μm, requiring a higher correction amount accuracy (less than 10 μm), but in the correction amount calculation method, the correction amount required for single mode can be calculated.

[0218] <How to create corrected table data>

[0219] Next, refer to Figure 8 This section explains how to create correction table data. Figure 8 This is a flowchart showing a method for creating correction table data.

[0220] In step S11, the control unit 6 sets a range for laser processing, that is, a grid pattern (for example, Figure 4 The processing light trajectory 28 is shown. The hypothetical workpiece 18 is a workpiece used to obtain correction table data.

[0221] Furthermore, the control unit 6 selects one processing light lattice point from among the plurality of processing light lattice points included in the lattice pattern.

[0222] In step S12, the control unit 6 uses the beam position measuring unit 38 to execute Figure 6 The correction amount is calculated by performing the series of processing shown.

[0223] In step S13 , the control unit 6 associates the correction amount calculated in step S12 with the scan angle used when calculating the correction amount, and stores the associated correction amount in the memory 31 as correction table data.

[0224] Then, the control unit 6 executes the process of step S14. In step S14, the control unit 6 determines whether the correction table data has been saved for all of the plurality of processing light grid points included in the grid pattern set in step S11.

[0225] In step S14 , when the storage of the correction table data at all the processing light lattice points has not been completed (step S14 : No), the control unit 6 executes the process of step S15 .

[0226] In step S15 , the control unit 6 selects a new processing light grid point (ie, a processing light grid point for which the correction table data has not been saved), and then repeats the processing from step S12 onwards.

[0227] In step S14, when the correction table data has been saved for all the processing light grid points (step S14: Yes), the control unit 6 ends a series of processing. The correction table data can be obtained through this series of processing.

[0228] In addition, when the grid pattern set in step S11 is Figure 4 In the case of the 4×4 grid pattern shown, correction table data is created only for 16 processing light grid points. Preferably, a grid pattern including 16 or more processing light grid points is set to create more correction table data.

[0229] However, even if a large amount of correction table data is created, the scanning angle of the first mirror 13 can be set to any value as long as it is within the mechanical operating range. Therefore, there is a possibility that the scanning angle may not match the correction table data. In this case, it is necessary to interpolate the correction table data to determine the correction amount. The method of interpolating the correction table data to determine the correction amount will be described later.

[0230] <Processing data>

[0231] Next, processing data used for processing the workpiece 18 will be described.

[0232] In conventional laser processing equipment equipped with an fθ lens and a galvanometer mirror, a control unit controls the laser oscillator and galvanometer mirror using multiple processing data sets set in a time series. Each processing point on the surface of the workpiece is then processed sequentially in a time series. The multiple processing data sets include, for example, output command values to the laser oscillator, scan angles, and processing speeds, which are aggregated for each processing point.

[0233] In this embodiment, the data items of the processing data used by the laser processing device 1 include the output indication value to the laser oscillator 5 (also called laser output data), the position of the processing point 20 (also called the processing point position) and the scanning angle, and the above-mentioned correction amount is also added.

[0234] In the following description, processed data to which the correction amount is added as a data item is referred to as "corrected processed data."

[0235] Reference Figure 9 An example of corrected processed data will be described. Figure 9 This is a diagram showing an example of data items included in the corrected processed data.

[0236] The corrected processing data includes data number k, laser output data L k , processing point position x k , processing point position y k , scanning angle Scan angle Correction ψx k and the correction value ψy k .

[0237] Data number k indicates the order of the processed data. k is an integer greater than or equal to 1. In addition, the subscript k assigned to each data item other than data number k indicates the data item corresponding to the kth data number.

[0238] Laser output data L k Indicates the output instruction value to the laser oscillator 5.

[0239] Processing point position x k Indicates the position of the processing point 20 in the x-axis direction.

[0240] Processing point position y k Indicates the position of the processing point 20 in the y-axis direction.

[0241] Scan angle It shows the scanning angle of the first mirror 13 which is responsible for scanning in the x-axis direction.

[0242] Scan angle It shows the scanning angle of the first mirror 13 which is responsible for scanning in the y-axis direction.

[0243] Correction ψx k The correction amount of the measurement light deflecting unit 17 that corrects the position of the measurement light 15 in the x-axis direction is shown.

[0244] Correction value ψy k The correction amount of the measurement light deflecting unit 17 that corrects the position of the measurement light 15 in the y-axis direction is shown.

[0245] The scan angle in the corrected processed data is an example of the first instruction value. The correction amount in the corrected processed data is an example of the second instruction value.

[0246] Next, refer to Figure 10 This section explains how to create processing data. Figure 10 This is a flowchart for explaining a method for creating processed data.

[0247] In step S21 , the control unit 6 sets the data number k to be referred to to 0. The data number k is assigned to an area in the memory 31 where the processed data is stored.

[0248] In step S22, the control unit 6 sets the laser output data L in the area of data number k in the memory 31. k , processing point position x k And the processing point position y k .

[0249] These values are set by the user of the laser processing apparatus 1 using an operation unit (eg, a keyboard, a mouse, a touch panel, etc.) not shown in the figure in order to realize desired laser processing.

[0250] In step S23, the control unit 6 calculates the processing point position x based on the processing point position x set in step S22. k And the processing point position y k To calculate the scanning angle of the first mirror 13 The calculated scanning angle The data is stored in the area of data number k in the memory 31 .

[0251] When the focal length of the lens 14 is f, there is a relationship between the processing point position and the scanning angle (x k ,y k )=(2f·φx k , 2f·φy k ), so the scanning angle can be automatically determined based on the processing point position.

[0252] In addition, the relationship between the processing point position and the scanning angle, the corresponding table, etc. can also be set in advance by the user. In this case, the relationship between the processing point position and the scanning angle, the corresponding table, etc. can also be used to determine the scanning angle of the first mirror 13.

[0253] In step S24 , the control unit 6 determines whether or not the setting of the processing data has been completed for all the data numbers k.

[0254] In step S24 , when the setting of the processed data has not been completed for all the data numbers k (step S24 : No), the control unit 6 executes the process of step S25 .

[0255] In step S25 , the control unit 6 increments the referenced data number k by one, and then repeats the processing from step S22 onward.

[0256] In step S24 , when the setting of the processed data is completed for all the data numbers k (step S24 : Yes), the control unit 6 ends a series of processes.

[0257] Through the above processing, processing data can be set for all data numbers k.

[0258] <How to set the correction amount>

[0259] Next, the Figure 10 A method of setting the correction amount for each processing point position based on the processing data set according to the process.

[0260] First, use Figure 11 The structure of the correction table data for machining point positions is explained. Figure 11 1 is a diagram showing a machining point position correction table 34 schematically showing the structure of the machining point position correction table data.

[0261] exist Figure 11 , the corrected processing data set for each processing light grid point on the processing surface 19 is schematically shown as a plurality of data points 32 .

[0262] As mentioned above, Figure 11 The data point 32 shown includes a position on the processing surface 19 (ie, a processing point position), a scanning angle, and a correction amount.

[0263] Figure 11 The correction data point 33 shown is a point corresponding to the machining origin 26 on the machining surface 19 .

[0264] In the following description, for convenience, the scanning angle is used The position of each data point 32 in the correction number table 34 indicates the position of the processing point.

[0265] will be related to the scanning angle The data number of the corresponding direction is set to i, and the scanning angle The data number of the corresponding direction is set to j.

[0266] Each data point 32 holds the scan angle (Φx i , Φy j ) and the correction value (Ψx ij , Ψy ij ) combination, namely (Φx i , Φy j , Ψx ij , Ψy ij ).

[0267] Correction table scanning angle (Φx i , Φy j ) has a scanning angle elements.

[0268] Next, use Figure 12 The flow of the method for setting the correction amount will be described. Figure 12 This is a flowchart showing a method for setting the correction amount.

[0269] In step S31 , the control unit 6 sets the referenced data number k to zero.

[0270] In step S32, the control unit 6 checks the scan angle stored in the area of data number k in the memory 31. All correction tables in the correction table 34 of the processing point position are calculated using the scanning angle (Φx i , Φy j ) is compared. Thus, the control unit 6 determines whether there is a and Data numbers i, j.

[0271] That is, in step S32 , it is determined whether or not there is a data entry including a scan angle completely identical to the scan angle set by the user in the correction number table 34 for the machining point position.

[0272] In step S32, if there is and In the case of data numbers i and j (step S32: Yes), the control unit 6 executes the process of step S33.

[0273] In step S32, if there is no and In the case of data numbers i and j (step S32: No), the control unit 6 executes the process of step S34.

[0274] In step S33, the control unit 6 uses and The data number i, j, the correction amount is set to (ψx k ,y k )=(Ψx ij , Ψy ij ).

[0275] That is, in this step S33, since there is a data item including a scan angle completely identical to the scan angle set by the user, the corresponding correction value table correction amount is directly set as the correction amount.

[0276] In step S34, the control unit 6 uses the correction number table 34 of the processing point position to enclose the scanning angle set by the user. The data of the 4 closest points are interpolated and the correction amount (ψx k , ψy k ). The details of step S34 will be described later.

[0277] In step S35, the control unit 6 sets the correction amount (ψx k , ψy k ) is set (saved) to the area of data number k of the processing data in the memory 31.

[0278] In step S36 , the control unit 6 determines whether or not the setting of the correction amount has been completed for all the processing data stored in the memory 31 .

[0279] In step S36 , when the correction amount has not been set for all the processing data (step S36 : No), the control unit 6 executes the process of step S37 .

[0280] In step S37 , the control unit 6 increments the referenced data number k by one, and then repeats the processing from step S32 onward.

[0281] In step S37 , when the setting of the correction amount is completed for all the processed data (step S36 : Yes), the control unit 6 ends the series of processing.

[0282] Through the above processing, Figure 10 In the processing data set according to the process, the correction amount can be set for all data numbers k. In other words, corrected processing data can be generated.

[0283] <Details of interpolation processing>

[0284] Next, we will explain in detail Figure 12 The interpolation process in step S34 is performed at the scanning angle set by the user. The correction table within the data point 32 uses the scanning angle (Φx i , Φy j ) are inconsistent.

[0285] Figure 13 The scanning angle X and Figure 11 The correction table 34 for machining point positions shows a relationship between the scan angle X and the surrounding correction data points when the correction table uses scan angles for any data point 32 does not match.

[0286] and scanning angle The corresponding point is located within the grid formed by the four correction data points A to D.

[0287] The value of the corrected data point A is (Φx i , Φy j , Ψx ij , Ψy ij ). The value of the corrected data point B is (Φx i+1 , Φy j , Ψx i+1j , Ψy i+1j ). The value of the corrected data point C is (Φx i , Φy j+1 , Ψx ij+1 , Ψy ij+1 ). The value of the corrected data point D is (Φx i+1 , Φy j+1 , Ψx i+1j+1 , Ψy i+1j+1 ).

[0288] (equal signs do not hold at the same time), The relationship (the equal signs do not hold at the same time) holds.

[0289] The correction amount at this time (ψx k , ψy k ) Available scanning angle The values of and the values of the corrected data points A, B, C, and D are calculated using the following formulas (1) and (2).

[0290] ψx k =(E×Ψx ij +F×Ψx i+1j +G×Ψx ij+1 +H×Ψx i+1j+1 ) / J (1)

[0291] ψy k =(E×Ψy ij +F×Ψy i+1j +G×ΨY ij+1 +H×Ψy i+1j+1 ) / J (2)

[0292] In addition, E, F, G, H, and J in formulas (1) and (2) can be calculated by the following formulas (3) to (7).

[0293]

[0294]

[0295]

[0296]

[0297] J=(Φx i+1 -Φx i )×(Φy j+1 -Φy j ) (7)

[0298] The interpolation process described above allows the correction amount to be calculated based on the scan angle set by the user. Furthermore, although linear interpolation is used as an example in the interpolation process described above, other well-known two-dimensional interpolation techniques (such as spline interpolation and quadratic surface approximation) can be used instead of linear interpolation.

[0299] Alternatively, the correction value (Ψx ij ,Ψ yij ) to calculate the high-order approximate surface of the correction amount with respect to the scanning angle, and calculate the correction amount corresponding to the scanning angle. "The correction number table on the correction number table 34 uses the correction amount (Ψx ij , Ψyij )"express Figure 11 As a specific example of the calculation method of the approximate surface, a fitting method based on the least squares method can be used. For example, for a three-dimensional data set (x i ,y i , z i )(i=1...n), we can find the equation of a surface z=f(a j , x, y)(j=0...m-1) as an approximate surface. a j By substituting the scanning angle into the “three-dimensional data set (x i ,y i , z i )”, substitute the correction amount (either the x coordinate or the y coordinate) into the “3D data set (x i ,y i , z i )”, from which the scanning angle (Φx i , Φy j ) relative to the correction value Ψx ij The approximate surface, and the scanning angle (Φx i , Φy j ) relative to the correction value Ψy ij In this way, a relationship for obtaining the correction amount based on an arbitrary scanning angle can be derived.

[0300] <Laser processing method>

[0301] Next, use Figure 14 A laser processing method performed by the laser processing apparatus 1 according to an embodiment of the present disclosure will be described. Figure 14 This is a flowchart for explaining a laser processing method performed by the laser processing apparatus 1 according to the embodiment of the present disclosure.

[0302] In step S41 , the control unit 6 sets the referenced data number k to zero.

[0303] In step S42, the control unit 6 reads the corrected processing data (laser output data L) corresponding to the data number k from the memory 31. k , scanning angle and the correction value ψx k , ψy k ).

[0304] In step S43, the control unit 6 performs the following operations based on the scanning angle. The first mirror 13 is operated based on the correction amount (ψx k , ψy k ) to activate the measuring light deflection unit 17.

[0305] Specifically, the control unit 6 notifies the first driver 7 of the scanning angle Thus, the first driver 7 is based on the scanning angle And the first mirror 13 is put into action.

[0306] Furthermore, the control unit 6 notifies the second driver 8 of the correction amount (ψx k , ψy k ). Thus, the second driver 8 is based on the correction amount (ψx k , ψy k ) to activate the measuring light deflection unit 17.

[0307] In step S44, the control unit 6 performs the following operations based on the laser output data L k Then, the processing laser light 11 is oscillated from the laser oscillator 5 .

[0308] Specifically, the control unit 6 generates the laser output data L indicating the laser output value. k The laser oscillator 5 outputs the laser light based on the laser output data L. k The laser beam 11 is oscillated for processing.

[0309] In step S45 , the control unit 6 determines whether or not the laser processing corresponding to all the data numbers k stored in the memory 31 has been completed.

[0310] In step S45 , when the laser processing corresponding to all the data numbers k has not been completed (step S45 : No), the control unit 6 executes the process of step S46 .

[0311] In step S46 , the control unit 6 increments the referenced data number k by one, and then repeats the processing from step S42 onward.

[0312] In step S45 , when the laser processing corresponding to all the data numbers k is completed (step S45 : Yes), the control unit 6 ends the series of processing.

[0313] Through the above-mentioned processing, laser processing can be performed on all data numbers k.

[0314] <Keyhole Depth Measurement Method>

[0315] Next, refer to Figure 15 The flow of a method for measuring the depth of the keyhole 22 when executing the above-mentioned laser processing method will be described. Figure 15 This is a flowchart for explaining a method for measuring the depth of the keyhole 22 .

[0316] In step S51, the control unit 6 starts Figure 14Prior to the laser processing method shown, position data of the processing surface 19 of the unprocessed workpiece 18 is acquired.

[0317] The so-called position data is the height of the processing surface 19 in the unprocessed state (in other words, Figure 1 Furthermore, the control unit 6 outputs a command to the measurement processing unit 4 to start measuring the depth of the keyhole 22.

[0318] like Figure 14 When a series of processes related to the laser processing shown above is started, in step S52 , the measurement processing unit 4 outputs a command to the optical interferometer 3 to cause it to emit the measuring light 15 .

[0319] Then, the optical interferometer 3 generates an optical interference signal according to the optical path difference between the measurement light 15 reflected by the bottom surface of the keyhole 22 and the reference light.

[0320] In step S53, the measurement processing unit 4 calculates the depth (i.e., penetration) of the keyhole 22 using the position data of the machined surface 19 of the unmachined workpiece 18 and the optical interference signal generated by the optical interferometer 3. The control unit 6 then stores data representing the calculated depth of the keyhole 22 in the memory 31.

[0321] In step S54 , the control unit 6 determines whether or not to complete the measurement of the depth of the keyhole 22 .

[0322] For example, when a series of processes related to laser processing are not completed, the control unit 6 continues the measurement of the depth of the keyhole 22 , and when a series of processes related to laser processing are completed, the control unit 6 ends the measurement of the depth of the keyhole 22 .

[0323] In step S54 , when the measurement of the depth of the keyhole 22 has not been completed (step S54 : No), the control unit 6 repeats the processing after step S52 .

[0324] In step S54 , when the measurement of the depth of the keyhole 22 is completed (step S54 : Yes), the control unit 6 executes the process of step S55 .

[0325] In step S55 , after a series of processes related to laser processing are completed, the control unit 6 instructs the measurement processing unit 4 to complete the measurement of the depth of the keyhole 22 .

[0326] Furthermore, the aforementioned command to start the measurement of the depth of the keyhole 22 and the command to end the measurement of the depth of the keyhole 22 may be output from a command output unit (not shown) instead of being output by the control unit 6. In this case, the user can output these commands by operating the command output device via an operation unit such as a keyboard.

[0327] <Effect>

[0328] As described above, the beam position measurement unit 38 of this embodiment includes: a position measurement mirror 39 that reflects the processing laser 11 and the measurement light 15 that have passed through the lens 14; and a two-dimensional imaging element 40 that measures the positions of the processing laser 11 and the measurement light 15 reflected by the position measurement mirror 39.

[0329] The position measuring mirror 39 is set to have a reflectivity such that the processing laser light 11 has a wavelength and a power that allows the processing laser light 11 to be input to the two-dimensional imaging element 40 .

[0330] Furthermore, the two-dimensional imaging element 40 is provided at a position where the optical path length from the lens 14 to the two-dimensional imaging element 40 coincides with the optical path length from the lens 14 to the processing point 20 .

[0331] Furthermore, the laser processing apparatus 1 sets a target position on the processing surface 19 and sets a first instruction value (a scanning angle of the measurement light deflection unit 17 ) for causing the processing laser light 11 to reach the target position.

[0332] Furthermore, the laser processing apparatus 1 is configured to obtain a second instruction value (correction amount of the measurement light deflecting unit 17 ) based on the positions of the processing laser light 11 and the measurement light 15 measured by the beam position measuring unit 38 .

[0333] According to this configuration, it is possible to correct the deviation in the arrival positions of the processing laser light 11 and the measurement light 15 on the processing surface 19 after passing through the lens 14 , which is caused by the chromatic aberration of magnification of the lens 14 .

[0334] This allows the optical interferometer 3 to appropriately measure the depth of the keyhole 22. That is, the depth of the keyhole 22 can be accurately measured.

[0335] Figure 16 This is a diagram illustrating the trajectories of the processing laser light 11 and the measurement light 15 on the processing surface 19 in a state where the influence of magnification chromatic aberration is corrected by operating the measurement light deflection unit 17 .

[0336] according to Figure 16 It can be seen that the machining light locus 28 , which is the locus of the machining laser light 11 , and the measurement light locus 27 , which is the locus of the measurement light 15 , coincide with each other.

[0337] Furthermore, it can be seen that one processing light lattice point 30 at a specific location on the processing light trajectory 28 coincides with the corresponding measurement light lattice point 29 on the measurement light trajectory 27 .

[0338] The present disclosure is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the present disclosure.

[0339] [First Modification]

[0340] In the above-described embodiment, the case where the measurement light deflection unit 17 serving as a galvanometer mirror is used as the measurement light deflection unit for changing the optical axis direction of the measurement light 15 is described as an example, but the present invention is not limited thereto.

[0341] The measurement light deflecting unit used in the laser processing apparatus 1 is provided, for example, between the measurement light inlet 9 and the dichroic mirror 12 , and may be any structure capable of changing the optical axis direction of the measurement light 15 under the control of the control unit 6 .

[0342] An example of the measurement light deflection unit configured in this manner is shown in FIG. Figure 17 . Figure 17 It is a diagram schematically showing the configuration of a laser processing apparatus 1 according to a first modification example of the present disclosure.

[0343] Figure 17 The laser processing device 1 shown replaces Figure 1 The measuring light deflecting unit 17 shown above includes a second mirror 35 , and further includes a moving stage 36 and a stage driver 37 .

[0344] in addition, Figure 17 The laser processing device 1 shown does not have Figure 1 The collimating lens 16 is shown in FIG.

[0345] The second mirror 35 is a parabolic mirror fixed between the measurement light introduction port 9 and the dichroic mirror 12 .

[0346] In addition, the second mirror 35 may be a MEMS (Micro Electro Mechanical Systems) mirror or the like.

[0347] The movable stage 36 is disposed at the measurement light inlet 9. A stage driver 37 is electrically connected to the control unit 6 and operates the movable stage 36 based on instructions from the control unit 6. Consequently, the movable stage 36 moves in the y-axis and z-axis directions in the figure. In other words, the movable stage 36 moves in two directions perpendicular to the measurement optical axis 23.

[0348] The emission end of the measurement light 15 at the measurement light introduction port 9 is arranged to coincide with the focal point of the second mirror 35 . Thus, the measurement light 15 is reflected by the second mirror 35 and then becomes parallel light, which then travels toward the dichroic mirror 12 .

[0349] The movement of the movable stage 36 changes the angle of the measurement optical axis 23 from the second mirror 35 toward the dichroic mirror 12. That is, the measurement light deflection unit is composed of the movable stage 36 and the second mirror 35. This achieves the same effect as when using the galvanometer mirror, i.e., the measurement light deflection unit 17.

[0350] [Second Modification]

[0351] Figure 18 It is a diagram schematically showing the configuration of a laser processing apparatus 1 according to a second modification of the present disclosure. Figure 18 The laser processing device 1 shown replaces Figure 17 The second mirror 35 shown has Figure 1 The collimating lens 16 shown in FIG. further comprises a movable stage 36 and a stage driver 37. In addition, Figure 18 The laser processing device 1 shown does not have Figure 1 The measuring light deflecting unit 17 is shown in FIG.

[0352] In the laser processing apparatus 1 according to the first modification, the angle of the measurement optical axis 23 is changed by the second mirror 35 . In contrast, in the laser processing apparatus 1 according to the second modification, the angle of the measurement optical axis 23 is changed by the collimator lens 16 .

[0353] The movable stage 36 is disposed at the measurement light inlet 9. A stage driver 37 is electrically connected to the control unit 6 and operates the movable stage 36 based on instructions from the control unit 6. Consequently, the movable stage 36 moves in the y-axis and x-axis directions. In other words, the movable stage 36 moves in two directions perpendicular to the measurement optical axis 23.

[0354] The emission end of the measurement light 15 at the measurement light introduction port 9 is arranged to coincide with the focal point of the collimator lens 16 . Thus, the measurement light 15 passes through the collimator lens 16 and becomes parallel light, and then travels toward the dichroic mirror 12 .

[0355] The movement of the movable stage 36 changes the angle of the measurement optical axis 23 from the collimator lens 16 toward the dichroic mirror 12. That is, the measurement light deflection unit is composed of the movable stage 36 and the collimator lens 16. This achieves the same effect as when a galvanometer mirror, i.e., the measurement light deflection unit 17, is used as the measurement light deflection unit.

[0356] (Implementation Method 2)

[0357] Patent Document 2 discloses a method for accurately measuring the penetration depth of a laser beam into a workpiece using measurement light. This measurement is performed by aligning the position of the laser beam irradiated on the workpiece with the position of the measurement light irradiated on the workpiece. The laser processing apparatus employing this method includes optical components such as reflectors and lenses to guide the emitted laser beam and the measurement light to the workpiece.

[0358] In the aforementioned laser processing device, due to the relatively high laser output, the components securing the optical components can be thermally deformed during laser processing. If the laser irradiation position and the measurement light irradiation position within the workpiece are changed under these conditions, the laser irradiation position and the measurement light irradiation position within the workpiece will shift. Consequently, the laser irradiation position cannot be accurately measured.

[0359] One aspect of the present disclosure solves the above-mentioned problems, and an object thereof is to provide a laser processing apparatus that accurately aligns the irradiation position of laser light and the irradiation position of measurement light in a workpiece.

[0360] In order to achieve the above-mentioned purpose, a laser processing device in one embodiment of the present invention includes: a laser emitting unit for emitting laser light for processing a workpiece; a measuring light emitting unit for emitting measuring light for measuring the irradiation position of the laser light in the workpiece; a beam position measuring unit for deriving the relative position of the optical axis of the measuring light with respect to the optical axis of the laser light; and an optical path changing unit for changing the optical path of at least one of the laser light and the measuring light based on the relative position derived by the beam position measuring unit.

[0361] In addition, in order to achieve the above-mentioned purpose, an optical adjustment method of a laser processing device in one embodiment of the present invention is an optical adjustment method of a laser processing device as follows, wherein the laser processing device has a laser emitting portion for emitting laser light toward a workpiece, and a measuring light emitting portion for emitting measuring light for measuring the irradiation position of the laser light in the workpiece, and the optical adjustment method includes: a step of making the irradiation position of the laser light in the workpiece consistent with the irradiation position of the measuring light; a step of deriving the relative position of the optical axis of the measuring light irradiated toward the workpiece relative to the optical axis of the laser; and a step of changing the optical path of at least one of the laser and the measuring light based on the derived relative position.

[0362] According to one aspect of the present disclosure, the position of laser light irradiation and the position of measurement light irradiation in a workpiece can be aligned with high precision.

[0363] The laser processing apparatus may further include: a mirror for reflecting at least one of the laser light and the measurement light toward the workpiece; and a lens disposed between the mirror and the workpiece for converging the laser light and the measurement light on the workpiece. The beam position measuring unit may also be disposed between the mirror and the lens.

[0364] The beam position measuring unit may include: a reflecting unit for reflecting the laser light and the measuring light in a direction other than a direction toward the workpiece; and a light receiving unit for receiving the laser light and the measuring light reflected by the reflecting unit. The relative position may be derived based on the irradiation position of the laser light and the irradiation position of the measuring light on the light receiving unit.

[0365] The reflectivity of the laser beam of the reflecting portion may be set to a predetermined value or less.

[0366] The light beam position measuring unit may include a plurality of the reflecting units.

[0367] The laser processing apparatus may further include a measuring unit for measuring the depth of a processing point. The optical path changing unit may change the optical path of at least one of the laser light and the measurement light based on the depth of the processing point measured by the measuring unit so that the irradiation position of the laser light on the workpiece and the irradiation position of the measurement light coincide with each other, and the optical path of at least one of the laser light and the measurement light may be changed based on the relative position derived by the beam position measuring unit when the irradiation position of the laser light on the workpiece and the irradiation position of the measurement light coincide with each other.

[0368] The measuring unit may be an interferometer that measures the length of the optical path of the measuring light based on a waveform generated by interference between light reflected from the workpiece and the measuring light.

[0369] Hereinafter, the laser processing device 201 according to the second embodiment of the present disclosure will be described using the accompanying drawings. Figure 19 The upper side and the lower side are respectively set as the upper side and the lower side of the laser processing device 201, and similarly, the left side and the right side are respectively set as the left and the right side of the laser processing device 201, and similarly, the front side of the paper and the inside side of the paper are set as the front and the rear of the laser processing device 201 for explanation.

[0370] The laser processing device 201 includes a processing head 202, a measuring unit 203, a measurement processing unit 204, and a laser oscillator 205. The measuring unit 203 is an example of a "measurement light emitting unit." The measurement processing unit 204 is an example of a "measurement unit." The laser oscillator 205 is an example of a "laser emitting unit."

[0371] The processing head 202 receives input of processing light LB, which is laser light used to process the workpiece W. The processing head 202 irradiates the workpiece W, which is positioned below the processing head 202, with the input processing light LB. Furthermore, the processing head 202 receives input of measurement light MB, which is used to measure the irradiation position of the processing light LB on the workpiece W. The processing head 202 irradiates the workpiece W with the input measurement light MB.

[0372] The measuring unit 203 is, for example, an optical interferometer for OCT (Optical Coherence Tomography) measurement. The measuring unit 203 emits laser light for OCT measurement as measurement light MB. The wavelength of the measurement light MB is, for example, 1300 nm. The emitted measurement light MB is input from the measurement light inlet 206 into the machining head 202 and travels downward.

[0373] Laser oscillator 205 oscillates processing light LB. The oscillated processing light LB is input into processing head 202 from processing light inlet 207, located to the left of measurement light inlet 206, and travels downward. Processing light LB is, for example, a YAG laser or a fiber laser. The wavelength of processing light LB differs from that of measurement light MB, for example, being 1064 nm. Below processing light inlet 207 in processing head 202, a first mirror 208 and a first lens 209 are located. First lens 209 is an example of a "lens."

[0374] The processing light LB input from the processing light introduction port 207 passes through the first mirror 208. The first mirror 208 is a dichroic mirror and has the characteristic of transmitting light of the wavelength of the processing light LB and reflecting light of the wavelength of the measurement light MB.

[0375] The processing light LB is then focused by the first lens 209 onto a processing point WP on the processing surface S of the workpiece W. This laser processing of the processing point WP occurs. At this point, the workpiece W melts at the processing point WP, forming a molten pool M. Furthermore, the molten metal in the molten pool M evaporates, and the pressure of the vapor generated by the evaporation forms a keyhole H.

[0376] The measurement light MB input from the measurement light inlet 206 is converted into parallel light by the collimator lens 210, which is arranged below the measurement light inlet 206. Furthermore, the measurement light MB is reflected by the second mirror 211, which is arranged below the collimator lens 210, toward the first mirror 208, which is arranged on the optical path of the processing light LB. The measurement light MB is then reflected by the first mirror 208 toward the processing point WP. The first mirror 208 and the second mirror 211 function as a "mirror."

[0377] Furthermore, the second mirror 211 is provided with an angle adjustment mechanism (not shown). The angle adjustment mechanism changes the angle of the second mirror 211. By changing the angle of the second mirror 211 by the angle adjustment mechanism, the second mirror 211 changes the optical path of the measurement light MB. The second mirror 211 is an example of an "optical path changing unit."

[0378] The measurement light MB is then focused by the first lens 209 and travels toward the processing point WP. As will be described later, the angle of the second mirror 211 is adjusted so that the measurement light MB is irradiated onto the lowest point of the keyhole H formed at the processing point WP.

[0379] Next, the measuring light MB is reflected at the lowest point of the keyhole H and travels back in time along the optical path of the measuring light MB to reach the measuring unit 203. The measuring unit 203 generates an optical interference intensity signal based on interference caused by the difference between the optical path lengths of the reflected measuring light MB and the emitted measuring light MB.

[0380] The measurement processing unit 204 measures the depth of the keyhole H, that is, the penetration depth of the processing point WP, based on the optical interference intensity signal generated by the measurement unit 203. The penetration depth is the distance between the lowest point of the keyhole H and the processing surface S.

[0381] Furthermore, the laser processing apparatus 201 further includes a beam position measuring unit 220 and a control device 230 .

[0382] The beam position measuring unit 220 derives the relative position of the optical axis of the measurement light MB with respect to the optical axis of the processing light LB. The beam position measuring unit 220 is disposed between the first mirror 208 and the first lens 209. The beam position measuring unit 220 includes a reflecting unit 221, a beam terminator 222, a second lens 223, and a light receiving unit 224.

[0383] The reflecting portion 221 and the beam terminator 222 are configured to be able to move at a first position P1 ( Figure 19 ) and the second position P2 ( Figure 20 The second lens 223 and the light receiving unit 224 are arranged on the left side of the reflecting unit 221.

[0384] When located at the second position P2, the reflecting unit 221 is a mirror that reflects the processing light LB and the measurement light MB toward the second lens 223. Furthermore, the reflecting unit 221 has the characteristic of separating light of the wavelength of the processing light LB into reflected light and transmitted light, while totally reflecting light of the wavelength of the measurement light MB. The reflectivity of the processing light LB by the reflecting unit 221 is set to a predetermined value. The predetermined value is a value that ensures that the intensity of the reflected processing light LB incident on the light receiving unit 224 falls within a predetermined range. The predetermined range has a lower limit lower than the intensity of the measurement light MB and an upper limit greater than the intensity of the measurement light MB, and represents the range of light intensities that can be received by the light receiving unit 224.

[0385] For example, if a fiber laser with a rated output of 1 kW or more is selected as processing light LB, the minimum output of processing light LB is approximately 100 W. On the other hand, if an OCT light source is used as measurement light MB, the output of measurement light MB is approximately several tens of mW. Therefore, in order to reduce the output of 100 W processing light LB to the same level (several tens of mW) as measurement light MB, the reflectivity of processing light LB at the reflector 221 is preferably set to 0.1% or less. Furthermore, since measurement light MB does not need to be attenuated, the reflectivity of measurement light MB at the reflector 221 is preferably set to 90% or greater.

[0386] Furthermore, when irradiating the light receiving unit 224 with the processing light LB, the output of the processing light LB is preferably set to 10% or more of the rated output of the laser oscillator 205. This is because, particularly when the laser oscillator 205 is a fiber laser, if the output of the processing light LB is less than 10% of the rated output, the oscillation state of the processing light LB becomes unstable, and the accuracy of the irradiation position LP of the processing light LB on the light receiving unit 224 decreases.

[0387] The beam terminator 222 receives the transmitted light having passed through the reflecting portion 221 at the second position P2 and terminates the transmitted light.

[0388] The second lens 223 converges the reflected light and the measurement light MB. The converged reflected light and the measurement light MB travel toward the light receiving unit 224.

[0389] The light receiving unit 224 receives the reflected light and the measurement light MB. The light receiving unit 224 is a two-dimensional imaging element sensitive to the wavelengths of the processing light LB and the measurement light MB. For example, the light receiving unit 224 may be a commercially available industrial camera or a two-dimensional beam profiler using a device such as a CCD (Charge-Coupled Device), a CMOS (Complementary Metal Oxide Semiconductor), or InGaAs (Indium Gallium Arsenide).

[0390] The shape of the second lens 223 and the distance between the light receiving unit 224 and the second lens 223 are set so that the focal points of the condensed reflected light and measurement light MB are located on the light receiving surface of the light receiving unit 224 that receives the reflected light and measurement light MB.

[0391] The control device 230 is a computer that performs overall control of the laser processing apparatus 201. The control device 230 controls the angle adjustment mechanism to adjust the angle of the second mirror 211.

[0392] Next, use Figure 21 The operation of the laser processing device 201 and the program executed by the control device 230 are explained with reference to the flowchart of FIG. This program performs optical adjustment so that the irradiation position of the processing light LB and the irradiation position of the measurement light MB in the workpiece W are consistent. From the state where the reflecting unit 221 and the beam terminator 222 are located at the first position P1 ( Figure 19 ) begins the description.

[0393] The control device 230 determines in S100 whether the current optical adjustment is the first optical adjustment. If the irradiation position MP of the measurement light MB relative to the irradiation position LP of the processing light LB in the light receiving unit 224, i.e., the relative position R, is not stored in the control device 230, the current optical adjustment is the first optical adjustment. In this case (yes in S100), the control device 230 aligns the irradiation position of the processing light LB and the irradiation position of the measurement light MB on the workpiece W in S102.

[0394] Specifically, the control device 230 irradiates the processing light LB onto the processing surface of an adjustment workpiece (not shown) prepared for optical adjustment, thereby forming a microhole. Next, the control device 230 adjusts the angle of the second mirror 211 to change the optical path of the measurement light MB while scanning the microhole with the measurement light MB. Based on the measurement results of the measurement processing unit 204, the control device 230 derives the lowest point of the microhole, i.e., the position where the optical path length of the measurement light MB is the longest. The lowest point of the microhole corresponds to the irradiation position of the processing light LB. By adjusting the angle of the second mirror 211 so that the irradiation position of the measurement light MB coincides with the lowest point of the microhole, the control device 230 aligns the irradiation position of the processing light LB and the irradiation position of the measurement light MB on the adjustment workpiece. Consequently, the irradiation position of the processing light LB and the irradiation position of the measurement light MB on the actual workpiece W coincide.

[0395] Next, the control device 230 moves the reflecting unit 221 and the beam terminator 222 to the second position P2 ( Figure 20The transmitted light of the machining light LB is terminated by the beam terminator 222. On the other hand, the reflected light of the machining light LB and the measurement light MB are reflected by the reflecting portion 221 and converged by the second lens 223 to be irradiated onto the light receiving portion 224.

[0396] At this time, although the irradiation position of the processing light LB and the irradiation position of the measurement light MB on the workpiece W coincide with each other, the irradiation position LP of the reflected light on the light receiving unit 224 and the irradiation position MP of the measurement light MB do not coincide with each other ( Figure 22 This is because, even if the irradiation position of the processing light LB and the irradiation position of the measurement light MB on the workpiece W coincide, since the processing light LB and the measurement light MB have different wavelengths as described above, the optical axis of the processing light LB and the optical axis of the measurement light MB do not coincide due to the influence of the chromatic aberration of the first lens 209. Furthermore, the processing light LB, i.e., the reflected light, and the measurement light MB irradiated on the light receiving unit 224 are converged by the second lens 223, which has a different chromatic aberration from the first lens 209. For these reasons, the irradiation position LP of the reflected light and the irradiation position MP of the measurement light MB on the light receiving unit 224 do not coincide.

[0397] However, at this time, the relative position R of the irradiation position MP of the measuring light MB in the light receiving portion 224 relative to the irradiation position LP of the reflected light of the processing light LB (i.e., the offset between the irradiation position LP of the reflected light and the irradiation position MP of the measuring light MB) is the relative position R in the light receiving portion 224 when the irradiation position of the processing light LB and the irradiation position of the measuring light MB in the workpiece W are consistent.

[0398] Relative position R is measured by light receiving unit 224. Furthermore, relative position R in light receiving unit 224 is correlated with the relative position of the optical axis of measurement light MB relative to the optical axis of processing light LB. In other words, light receiving unit 224 indirectly derives the relative position of the optical axis of measurement light MB relative to the optical axis of processing light LB. The measurement results of light receiving unit 224 are output to control device 230.

[0399] Through S106, the control device 230 derives and stores the irradiation position MP of the measurement light MB in the light receiving part 224 relative to the irradiation position LP of the reflected light, that is, the relative position R, based on the measurement result of the light receiving part 224, as the relative position R in the light receiving part 224 when the irradiation position of the processing light LB in the workpiece W is consistent with the irradiation position of the measurement light MB.

[0400] Next, the control device 230 moves the reflecting unit 221 and the beam terminator 222 to the first position P1 in S108, thereby terminating the program. The workpiece W is then processed. The control device 230 executes the program at predetermined timings (e.g., predetermined time intervals (10 seconds)) to perform optical adjustments during processing.

[0401] When the program is restarted, the control device 230 determines whether the current optical adjustment is the first optical adjustment in S100. If the relative position R is stored in the control device 230, the current optical adjustment is the second or subsequent optical adjustment. In this case (No in S100), the control device 230 moves the reflecting unit 221 and the beam terminator 222 to the second position P2 ( Figure 20 ). As described above, the processing light LB and the measurement light MB are reflected by the reflecting portion 221 and condensed by the second lens 223 to be irradiated onto the light receiving portion 224.

[0402] At this time, the irradiation position LP of the reflected light of the processing light LB and the irradiation position MP of the measurement light MB (the irradiation position MP of the measurement light MB before adjustment) in the light receiving unit 224 are displaced from the time of the first optical adjustment ( Figure 23 ). That is, the relative position R in the light receiving unit 224 is different from the relative position R derived by the control device 230.

[0403] This is because the processing light LB has a relatively high output, which increases the temperature of the components of the processing head 202, and thus the temperature of the fixing member that secures the components. This causes thermal deformation of the fixing member, which in turn causes displacement of the components, and thus changes the optical paths of the processing light LB and the measurement light MB. Furthermore, at this time, when the reflector 221 and the beam terminator 222 are at the first position P1, the angles of incidence of the processing light LB and the measurement light MB on the first lens 209 also shift, and consequently, the irradiation positions of the processing light LB and the measurement light MB on the workpiece W also shift.

[0404] Next, the control device 230 adjusts the relative position R in the light receiving unit 224 based on the derived relative position R in S112. Specifically, the control device 230 adjusts the angle of the second mirror 211 to change the optical path of the measurement light MB, thereby displacing the irradiation position MP of the measurement light MB in the light receiving unit 224 so that the relative position R in the light receiving unit 224 becomes the derived relative position R. As a result, the adjusted irradiation position MP of the measurement light MB relative to the irradiation position LP of the reflected light in the light receiving unit 224, that is, the adjusted relative position R, becomes consistent with the derived relative position R ( Figure 23 ).

[0405] Then, the control device 230 moves the reflecting unit 221 and the beam terminator 222 to the first position P1 in S108. This causes the processing light LB and the measuring light MB to irradiate the workpiece W. At this time, since the relative position R of the light receiving unit 224 is adjusted, the irradiation position of the processing light LB and the irradiation position of the measuring light MB on the workpiece W coincide.

[0406] In this way, in the second and subsequent optical adjustments, the irradiation position of the processing light LB and the irradiation position of the measurement light MB on the workpiece W can be aligned without scanning the micro-hole with the measurement light MB, allowing the control device 230 to perform optical adjustments more simply. Furthermore, compared to deriving the irradiation position of the measurement light MB corresponding to the lowest point of the micro-hole by scanning the measurement light MB, the control device 230 can more accurately derive the irradiation position of the measurement light MB relative to the irradiation position of the processing light LB on the light receiving unit 224 by deriving the irradiation position MP of the measurement light MB relative to the irradiation position LP of the processing light LB. Consequently, the control device 230 can align the irradiation position of the processing light LB and the irradiation position of the measurement light MB on the workpiece W with high precision. Furthermore, the second optical adjustment does not require the preparation of an adjustment workpiece.

[0407] According to the above-mentioned embodiment, the laser processing device 201 includes: a laser oscillator 205, which emits processing light LB toward the workpiece W; a measuring unit 203, which emits measuring light MB for measuring the irradiation position of the processing light LB in the workpiece W; a light beam position measuring unit 220, which derives the relative position of the optical axis of the measuring light MB with respect to the optical axis of the processing light LB; and a second mirror 211, which changes the optical path of the measuring light MB based on the relative position R derived by the light beam position measuring unit 220.

[0408] Thus, the position of the workpiece W irradiated with the machining light LB and the position of the workpiece W irradiated with the measurement light MB can be aligned easily and with high precision.

[0409] The laser processing apparatus 201 further includes a first mirror 208 and a second mirror 211 for reflecting the measuring light MB toward the irradiation position of the processing light LB in the workpiece W; and a first lens 209 disposed between the first mirror 208 and the second mirror 211 and the workpiece W, for converging the processing light LB and the measuring light MB onto the workpiece W. A beam position measuring unit 220 is disposed between the first mirror 208 and the second mirror 211 and the first lens 209.

[0410] Thus, the beam position measuring unit 220 can derive the relative position of the optical axis of the measuring light MB with respect to the optical axis of the processing light LB, including the influence of changes in the optical path of the measuring light MB caused by the displacement of the first mirror 208 and the second mirror 211 .

[0411] The beam position measuring unit 220 also includes a reflecting unit 221 for reflecting the processing light LB and the measuring light MB in a direction other than the direction toward the workpiece W, and a light receiving unit 224 for receiving the processing light LB and the measuring light MB reflected by the reflecting unit 221. The relative position R is derived based on the irradiation position LP of the processing light LB and the irradiation position MP of the measuring light MB at the light receiving unit 224.

[0412] As a result, the position of the workpiece W irradiated with the machining light LB and the position of the workpiece W irradiated with the measurement light MB can be aligned more simply and with higher accuracy.

[0413] Furthermore, the reflectivity of the processing light LB of the reflecting portion 221 is set to be equal to or less than a predetermined value.

[0414] Thus, the intensity of the reflected light and the intensity of the measurement light MB irradiated on the light receiving unit 224 can be kept within a predetermined range. Therefore, the irradiation position MP of the measurement light MB relative to the irradiation position LP of the reflected light can be easily derived using a single light receiving unit 224, rather than using multiple light receiving units 224. This is because, if either the intensity of the reflected light or the intensity of the measurement light MB deviates from the predetermined range, a light receiving unit 224 corresponding to the respective intensities is required.

[0415] The laser processing apparatus 201 further includes a measurement processing unit 204 for measuring the depth of the processing point WP. The second mirror 211 changes the optical path of the measurement light MB based on the depth of the processing point WP measured by the measurement processing unit 204 so that the irradiation position of the processing light LB on the workpiece W coincides with the irradiation position of the measurement light MB. The second mirror 211 changes the optical path of the measurement light MB based on the relative position R derived by the beam position measurement unit 220 when the irradiation position of the processing light LB on the workpiece W coincides with the irradiation position of the measurement light MB.

[0416] As a result, the alignment between the irradiation position of the processing light LB and the irradiation position of the measurement light MB on the workpiece W can be achieved more reliably and with high precision.

[0417] The measurement processing unit 204 is an interferometer that measures the length of the optical path of the measurement light MB based on a waveform generated by interference between the light reflected by the workpiece W and the measurement light MB.

[0418] Thus, the laser processing apparatus 201 can accurately derive the irradiation position of the measurement light MB in the workpiece W.

[0419] The present disclosure is not limited to the embodiments described above, and various modifications of the embodiments and combinations of components from different embodiments are also within the scope of the present invention without departing from the spirit of the present invention.

[0420] For example, Figure 21 The flowchart shown is described as a program executed by the control device 230, but it can also be executed by the user of the laser processing device 201. Figure 21 In this case, the control device 230 includes a display unit (not shown) for displaying the relative position R in the light receiving unit 224, and an operation unit (not shown) for allowing the user to switch the positions of the reflecting unit 221 and the beam terminator 222 and adjust the angle of the second mirror 211.

[0421] Furthermore, the relative position R in the light receiving unit 224 is adjusted by displacing the irradiation position MP of the measurement light MB in the light receiving unit 224. Alternatively, the relative position R can be adjusted by displacing the irradiation position LP of the reflected light in the light receiving unit 224. In this case, for example, an angle adjustment mechanism can be provided at the processing light inlet 207, and the control device 230 can control this angle adjustment mechanism to change the optical path of the processing light LB. Alternatively, angle adjustment mechanisms can be provided at both the second mirror 211 and the processing light inlet 207, and the control device 230 can control these angle adjustment mechanisms to change the optical paths of the processing light LB and the measurement light MB, thereby adjusting the relative position R in the light receiving unit 224. Furthermore, the angle adjustment mechanism provided at the second mirror 211 can also be provided at the measurement light inlet 206. Furthermore, each angle adjustment mechanism can be controlled by the control device 230 or manually.

[0422] In addition, in the above embodiment, the light beam position measuring unit 220 includes one reflecting unit 221, but may include a plurality of reflecting units 221. In this case, Figure 24 As shown, the optical fiber ...

[0423] Furthermore, the reflecting unit 221 utilizes a mirror that divides the processing light LB into transmitted light and reflected light, but may instead include a mirror that totally reflects the processing light LB. In this case, the beam terminator 222 may not be provided.

[0424] Furthermore, in the above-described embodiment, the processing light LB and the measuring light MB are reflected by the reflecting unit 221 and transmitted through the second lens 223 before being irradiated onto the light receiving unit 224. Alternatively, the processing light LB and the measuring light MB may be transmitted through the second lens 223 and reflected by the reflecting unit 221 before being irradiated onto the light receiving unit 224. In this case, the second lens 223 is configured to be movable. Thus, even when a second lens 223 with a long focal length is selected, the optical paths of the reflected light and the measuring light MB are bent, thereby preventing an increase in the size of the beam position measuring unit 220.

[0425] Alternatively, the beam position measurement unit 220 may be composed of two light receiving units (not shown). During the second optical adjustment, the first light receiving unit is positioned between the processing light inlet 207 and the first mirror 208, and the processing light LB is irradiated onto the first light receiving unit. During the second optical adjustment, the second light receiving unit is positioned between the collimating lens 210 and the second mirror 211, and the measurement light MB is irradiated onto the second light receiving unit. The center of the processing light LB irradiated onto the first light receiving unit corresponds to the optical axis of the processing light. Furthermore, the center of the measurement light irradiated onto the second light receiving unit corresponds to the optical axis of the measurement light MB. Therefore, based on the center positions of the processing light LB irradiated onto the first light receiving unit and the center positions of the measurement light MB irradiated onto the second light receiving unit, the control device 230 can directly derive the relative position of the optical axis of the measurement light MB relative to the optical axis of the processing light LB. Furthermore, in this case, the control device 230 controls the angle adjustment mechanism positioned at the measurement light inlet 206 to adjust the angle of the measurement light inlet 206, thereby changing the optical path of the measurement light MB.

[0426] Furthermore, in the above-described embodiment, the reflecting portion 221 is formed in a plate shape, but the portion that reflects the machining light LB and the measurement light MB only needs to be planar, and may be in a shape other than a plate shape.

[0427] Furthermore, the beam position measuring unit 220 includes the beam terminator 222 . However, if the intensity of the transmitted light is relatively low, the beam terminator 222 may not be included instead.

[0428] Furthermore, the reflecting unit 221 totally reflects the measuring light MB. Alternatively, the reflectivity may be set so that the measuring light MB is divided into reflected light and transmitted light. In this case, the relative position R of the light receiving unit 224 can be derived in real time while the workpiece W is being processed. Therefore, the irradiation position of the processing light LB and the irradiation position of the measuring light MB on the workpiece W can be aligned in real time while the workpiece W is being processed.

[0429] In addition, when using a laser (for example, a single-mode fiber laser) in which the beam diameter at the processing point WP is less than 50 μm, the accuracy of adjusting the irradiation position of the processing light LB and the irradiation position of the measuring light MB is required to be less than 10 μm, but the optical adjustment of the above-mentioned laser processing device 201 can cope with this required accuracy.

[0430] In addition, the first optical adjustment is performed by scanning the micro hole formed in the processing point WP with the measuring light MB as described above, but instead, Figure 25 As shown, the measurement may be performed using a plate member 140 having a slit 141 formed therein and a power meter 150 for detecting the intensity of the processing light LB.

[0431] In this case, the control device 230 changes the optical path of the processing light LB so that the processing light LB scans the slit 141, and the power meter 150 detects changes in the intensity of the processing light LB. Based on the detected changes in the intensity of the processing light LB, the control device 230 adjusts the relative position of the optical path of the processing light LB with respect to the slit 141. Similarly, the control device 230 adjusts the relative position of the optical path of the measurement light MB with respect to the slit 141 so that the irradiation position of the processing light LB and the irradiation position of the measurement light MB on the workpiece W coincide.

[0432] Furthermore, the mirrors that reflect the measurement light MB toward the irradiation position of the processing light LB in the workpiece W are the first mirror 208 and the second mirror 211. However, the number of mirrors is not limited to this, as is self-evident. For example, the number of mirrors can be two or more. Furthermore, the configuration of the measurement light inlet 206 can be changed to only one mirror. In this case, for example, the measurement light inlet 206 and the collimating lens 210 can be placed to the right of the first mirror 208, so that the only mirror is the first mirror 208. Furthermore, in this case, an angle adjustment mechanism can be provided on the first mirror 208.

[0433] The first mirror 208 has the characteristic of transmitting the processing light LB and reflecting the measurement light MB. However, it may also have the characteristic of transmitting the measurement light MB and reflecting the processing light LB. In this case, for example, the processing light LB is incident on the first mirror 208 from the right, and the measurement light MB is incident on the first mirror 208 from above. Alternatively, the first mirror 208 may have the characteristic of reflecting both the processing light LB and the measurement light MB. In this case, for example, the processing light LB and the measurement light MB are incident on the first mirror 208 from the right. In this way, the first mirror reflects at least one of the processing light LB and the measurement light MB toward the workpiece W.

[0434] Industrial applicability

[0435] The laser processing apparatus and laser processing method disclosed herein are useful in laser processing of, for example, automobiles, electronic components, and the like.

Claims

1. A laser processing device comprising: A laser oscillator for oscillating a processing laser beam for irradiating a processing point on a processing surface of a workpiece; a coupling mirror for deflecting or transmitting the processing laser light and the measurement light irradiated to the processing point toward the processing point; a measurement light deflecting unit for changing an incident angle of the measurement light onto the coupling mirror; a lens for focusing the processing laser light and the measurement light on the processing point; a control unit that controls the laser oscillator and the measurement light deflection unit; a measurement processing unit that measures the depth of the keyhole formed at the processing point by irradiating the processing laser beam using an optical interference signal based on interference caused by an optical path difference between the measurement light and the reference light reflected at the processing point; and The beam position measuring unit measures the positions of the processing laser beam and the measurement light.

2. The laser processing device according to claim 1, wherein: It also includes a first mirror that changes the traveling direction of the processing laser light and the measurement light irradiated to the processing point, The control unit further controls the first mirror based on the processing data.

3. The laser processing device according to claim 2, wherein: The processing data includes: a first indicator value indicating the amount of movement of the first mirror; and a second indicator value indicating the amount of movement of the measurement light deflection unit. The beam position measuring unit includes: a position measuring mirror that reflects the processing laser light and the measuring light that have passed through the lens; and a two-dimensional imaging element that measures the positions of the processing laser light and the measuring light reflected by the position measuring mirror. The control unit sets a target position on the processing surface and sets the first instruction value for causing the processing laser to reach the target position, and calculates the second instruction value based on the positions of the processing laser and the measurement light measured by the two-dimensional imaging element.

4. The laser processing device according to claim 3, wherein: The position measuring mirror is set to have a reflectivity of a wavelength of the processing laser light such that the processing laser light has a power capable of being input to the two-dimensional imaging element. The two-dimensional imaging element is provided at a position where the optical path length from the lens to the two-dimensional imaging element matches the optical path length from the lens to the processing point.

5. The laser processing device according to claim 3 or 4, wherein: The position measuring mirror is composed of a plurality of mirrors.

6. The laser processing device according to claim 3 or 4, wherein: The reflectivity of the position measuring mirror at the wavelength of the processing laser light is 0.1% or less.

7. The laser processing device according to claim 3 or 4, wherein: The control unit sets a grid pattern on the processing surface and sets grid points of the grid pattern as the target positions.

8. The laser processing device according to claim 1 or 2, wherein: The beam position measuring unit derives the relative position of the optical axis of the measuring light with respect to the optical axis of the processing laser light. The control unit controls the coupling mirror having an angle adjustment function or the measurement light deflecting unit based on the relative position derived by the beam position measuring unit.

9. The laser processing device according to claim 8, wherein: The lens is arranged between the coupling mirror and the workpiece. The beam position measuring unit is arranged between the coupling mirror and the lens.

10. The laser processing device according to claim 8, wherein: The light beam position measuring unit comprises: a reflecting portion that reflects the processing laser light and the measuring light in a direction other than a direction toward the workpiece; and a light receiving unit that receives the processing laser light and the measurement light reflected by the reflecting unit, The beam position measuring unit derives the relative position based on an irradiation position of the processing laser light and an irradiation position of the measurement light in the light receiving section.

11. The laser processing device according to claim 10, wherein: The reflectivity of the processing laser light of the reflecting portion is set to be equal to or less than a predetermined value.

12. The laser processing device according to claim 10 or 11, wherein: The light beam position measuring unit includes a plurality of the reflecting parts.

13. The laser processing device according to claim 8, wherein: The control unit controls the coupling mirror or the measuring light deflecting unit so as to: changing an optical path of at least one of the processing laser light and the measurement light so that an irradiation position of the processing laser light and an irradiation position of the measurement light on the workpiece coincide with each other; The optical path of at least one of the processing laser light and the measurement light is changed based on the relative position derived by the beam position measuring unit when the irradiation position of the processing laser light and the irradiation position of the measurement light on the workpiece coincide with each other.

14. The laser processing device according to claim 13, wherein: The measurement processing unit is an interferometer that measures the length of the optical path of the measurement light based on the waveform generated by the interference.

15. The laser processing device according to claim 8, wherein The control unit controls the coupling mirror or the measurement light deflecting unit so that the irradiation position of the processing laser light on the workpiece coincides with the irradiation position of the measurement light. When the irradiation position of the processing laser beam on the workpiece coincides with the irradiation position of the measurement light, the control unit stores the relative position derived by the beam position measuring unit. The control unit controls the coupling mirror or the measurement light deflecting unit so that the relative position between the irradiation position of the processing laser light and the irradiation position of the measurement light on the beam position measuring unit matches the stored relative position.

16. A laser processing method performed by a laser processing apparatus comprising: a laser emitting unit for emitting laser light toward a workpiece; and a measurement light emitting unit for emitting measurement light for measuring an irradiation position of the laser light in the workpiece. The laser processing method comprises: A step of aligning an irradiation position of the laser light and an irradiation position of the measurement light on the workpiece based on the positions of the laser light and the measurement light measured by a beam position measuring unit that measures the positions of the laser light and the measurement light.

17. The laser processing method according to claim 16, wherein: Also includes: a step of deriving a relative position of the optical axis of the measurement light irradiated onto the workpiece with respect to the optical axis of the laser light; and A step of changing an optical path of at least one of the laser light and the measurement light based on the derived relative position.

18. The laser processing method according to claim 16, wherein: The laser processing device further includes: a first mirror for changing the traveling directions of the laser light and the measuring light; and a measuring light deflecting unit for changing the incident angle of the measuring light on the first mirror. The step of aligning the irradiation position of the laser light and the irradiation position of the measurement light in the workpiece includes: a step of setting a target position on a processing surface of the workpiece; a step of setting a first instruction value indicating an amount of movement of the first mirror for causing the laser beam to reach the target position; a step of obtaining a second indicator value indicating an amount of operation of the measurement light deflecting unit based on the positions of the laser light and the measurement light measured by the beam position measuring unit; and A step of controlling the laser emitting unit, the first mirror, and the measurement light deflecting unit based on processed data including the first instruction value and the second instruction value.

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