Laser processing device and laser processing method

Abstract

This invention provides a laser processing apparatus and a laser processing method. The laser processing apparatus sets a processing zone through a target position on a processing surface. Within the processing zone, a measurement zone centered on the target position is set. Within the measurement zone, multiple data acquisition positions, i.e., trajectories perpendicular to the processing direction, are set. Further, during processing within the processing zone, the laser processing apparatus acquires measurement data representing the shape of each small hole at each data acquisition position, creating projection data that overlaps the measurement data projected onto the processing direction. Based on the projection data, the laser processing apparatus calculates a second indication value in the direction perpendicular to the processing direction at the target position. Thus, a laser processing apparatus and laser processing method capable of accurately measuring the depth of small holes can be provided.

Description

Technical Field

[0001] This disclosure relates to laser processing apparatus and laser processing methods. Background Technology

[0002] For example, Japanese Patent Publication No. 2018-501964 (hereinafter referred to as "Patent Document 1") discloses a laser processing apparatus. The laser processing apparatus uses OCT (Optical Coherence Tomography) technology, which uses optical interferometry to visualize the internal structure of a sample, to measure the depth of a keyhole generated during metal processing by a laser.

[0003] The following uses Figure 26 The laser processing apparatus of Patent Document 1 will be described. Figure 26 This is a schematic diagram showing the structure of the laser processing apparatus disclosed in Patent Document 1.

[0004] like Figure 26 As shown, a processing laser 107 and a measuring light 105 are introduced into the welding head 108. The measuring light 105 is collimated by a collimation module 106 and a dichroic mirror 110, thus becoming a coaxial structure that shares the optical axis with the processing laser 107.

[0005] The measuring instrument includes an OCT optical system using an optical interferometer, which comprises: an analysis unit 100, an optical fiber 101, a beam splitter 103, an optical fiber 104, a reference arm 102, and a measuring arm 109. The measuring light 105, as the measuring light of the OCT optical system, is illuminated through the optical fiber 104.

[0006] The processing laser 107 and the measuring light 105 are focused by the condenser lens 111 and irradiated onto the workpiece 112. The workpiece 112 is processed by the processing laser 107. In other words, if the focused processing laser 107 irradiates the processing section 113 of the workpiece 112, the metal of the workpiece 112 melts. As a result, a small hole is formed by the pressure of the molten metal evaporating. Furthermore, the measuring light 105 is irradiated onto the bottom surface of the small hole.

[0007] At this time, an interference signal is generated based on the optical path difference between the measuring light 105 (reflected light) reflected by the pinhole and the light on the reference arm 102 side (reference light). Therefore, the depth of the pinhole can be determined based on the interference signal. The pinhole is immediately filled with the surrounding molten metal after its formation. Therefore, the depth of the pinhole is almost the same as the depth of the molten portion of the metal processing section (hereinafter referred to as "melting depth"). Therefore, the melting depth of the processing section 113 can be measured.

[0008] In recent years, laser processing apparatuses combining current mirrors and fθ lenses have become known. A current mirror is a reflector that allows precise control over the direction of laser reflection. An fθ lens is a lens that focuses the laser beam onto a processing point on the surface of the workpiece.

[0009] Therefore, it is considered to apply the method for measuring the depth of a pinhole disclosed in Patent Document 1 to the structure of a laser processing apparatus that combines a current mirror and an fθ lens. In this case, the following problem arises: Because the wavelengths of the processing laser and the measuring light are different, chromatic aberration occurs in the fθ lens. Consequently, a deviation occurs on the surface of the workpiece at the irradiation positions of the processing laser and the measuring light. Therefore, there is concern that the depth of the pinhole cannot be accurately measured using the measuring light. Summary of the Invention

[0010] This disclosure provides a laser processing apparatus and a laser processing method capable of accurately measuring the depth of a pinhole.

[0011] The laser processing apparatus disclosed herein includes: a laser oscillator that oscillates a processing laser to irradiate a processing point on the processing surface of a workpiece; and an optical interferometer that emits measurement light irradiating the processing point and generates an optical interference signal based on the interference caused by the optical path difference between the measurement light reflected at the processing point and a reference light. Furthermore, the laser processing apparatus includes: a first reflecting mirror that changes the travel direction of the processing laser and the measurement light; a second reflecting mirror that changes the incident angle of the measurement light toward the first reflecting mirror; and a lens that focuses the processing laser and the measurement light onto the processing point. Further, the laser processing apparatus includes: a control unit that controls the laser oscillator, the first reflecting mirror, and the second reflecting mirror based on corrected processing data; and a measurement processing unit that measures the depth of a small hole generated at the processing point by the irradiation of the processing laser based on the optical interference signal. The corrected processing data is used to eliminate deviations in the arrival positions of the processing laser and the measurement light on the processing surface caused by chromatic aberration of the lens. It includes an output indication value, a first indication value, and a second indication value set for each processing point. The output indication value represents the oscillation intensity of the processing laser, the first indication value represents the movement amount of the first reflector, and the second indication value represents the movement amount of the second reflector. The control unit sets a processing interval through a target position on the processing surface. Within the processing interval, a measurement interval centered on the target position is set. Within the measurement interval, multiple data acquisition positions, i.e., trajectories perpendicular to the processing direction, are set. Further, during processing within the processing interval, the control unit acquires measurement data representing the shape of the small holes at each data acquisition position, creates projection data that superimposes the measurement data onto the processing direction, and calculates a second indication value in the direction perpendicular to the processing direction at the target position based on the projection data.

[0012] Furthermore, in one aspect of the laser processing method disclosed herein, the method comprises: a first reflecting mirror that changes the travel direction of the processing laser and the measurement light; a second reflecting mirror that changes the incident angle of the measurement light toward the first reflecting mirror; and a lens that focuses the processing laser and the measurement light onto a processing point on the processing surface of the workpiece. The laser processing method, based on corrected processing data, controls the first and second reflecting mirrors to irradiate the workpiece with the processing laser and the measurement light, and measures the depth of a small hole formed at the processing point by irradiating the processing laser based on the interference caused by the optical path difference between the measurement light reflected at the processing point and the reference light. The corrected processing data is data used to eliminate deviations in the arrival position of at least one of the processing laser and the measurement light on the processing surface caused by chromatic aberration of the lens. The data includes an output indication value, a first indication value, and a second indication value preset for each processing point, wherein the output indication value represents the oscillation intensity of the processing laser, the first indication value represents the amount of movement of the first reflecting mirror, and the second indication value represents the amount of movement of the second reflecting mirror. Furthermore, the laser processing apparatus sets a processing zone through the target position on the processing surface. Within the processing zone, a measurement zone centered on the target position is set. Within the measurement zone, multiple data acquisition positions, i.e., trajectories perpendicular to the processing direction, are set. Further, during processing within the processing zone, the laser processing apparatus acquires measurement data representing the shape of the small holes at each data acquisition position, creating projection data that superimposes the measurement data onto the processing direction. Based on the projection data, a second indication value in the direction perpendicular to the processing direction at the target position is calculated.

[0013] This disclosure provides a laser processing apparatus and a laser processing method capable of accurately measuring the depth of a pinhole. Attached Figure Description

[0014] Figure 1 This is a diagram schematically illustrating the structure of a laser processing apparatus according to an embodiment of the present disclosure.

[0015] Figure 2 This is a schematic diagram of a laser processing apparatus that shows the state in which the first mirror moves from the origin position.

[0016] Figure 3 This diagram schematically illustrates a laser processing apparatus that corrects for deviations in the processing laser caused by magnification chromatic aberration and measures the respective arrival positions of the light.

[0017] Figure 4 It is a schematic diagram showing the processing laser on the processing surface and the trajectory of each light beam when only the first mirror is activated and scans the surface of the workpiece in a grid pattern.

[0018] Figure 5This is a flowchart illustrating the calculation method for the correction angle in a specified machining lattice point.

[0019] Figure 6 This is a diagram that schematically illustrates an example of the machining range and data acquisition range set when the y-axis is selected as the axis for obtaining the correction angle.

[0020] Figure 7 It is a diagram that schematically illustrates the relationship between the processing point and the data acquisition location during processing.

[0021] Figure 8 This is a chart showing an example of the measurement results of the pinhole shape in the x-direction when the machining direction is +x.

[0022] Figure 9 This is a chart showing an example of the measurement results of the small hole shape in the x-direction when the processing direction is -x.

[0023] Figure 10 This is a chart showing an example of the measurement results of the small hole shape in the y direction when the machining direction is +x.

[0024] Figure 11 This is a chart showing an example of the measurement results of the small hole shape in the y direction when the machining direction is -x.

[0025] Figure 12 This is an illustrative diagram used to illustrate an example of overlapping multiple measurement data.

[0026] Figure 13 It is a diagram illustrating an example of how to calculate the correction angle based on projection data.

[0027] Figure 14 It is a schematic diagram showing the cross-shaped machining marks where the machining lattice points intersect.

[0028] Figure 15 This is a flowchart illustrating the method for creating modified numerical data tables.

[0029] Figure 16 This diagram schematically illustrates an example of cross-shaped machining marks formed across all the machined light grid points.

[0030] Figure 17 This is a diagram illustrating an example of the structure of the corrected processing data.

[0031] Figure 18 It is a flowchart showing the method for creating processing data.

[0032] Figure 19 It is a diagram representing a modified number table that schematically illustrates the structure of the modified number table data.

[0033] Figure 20 This is a flowchart illustrating the method for setting the correction angle.

[0034] Figure 21 This is a graph showing the relationship between the scan angle X set by the user and the scan angles around it when the scan angles used for any data point in the correction table are inconsistent.

[0035] Figure 22 This is a flowchart illustrating a laser processing method.

[0036] Figure 23 This is a flowchart illustrating the method for measuring the depth of a pinhole.

[0037] Figure 24 It is a schematic diagram showing the trajectory of the processing laser and the measurement light in the processing surface, indicating the state of the state after the operation of the second reflecting mirror corrects the effect of magnification chromatic aberration.

[0038] Figure 25 This is a diagram schematically illustrating the structure of the laser processing apparatus involved in Modification 1 of this disclosure.

[0039] Figure 26 This is a schematic diagram of the laser processing apparatus disclosed in Patent Document 1. Detailed Implementation

[0040] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. Furthermore, common structural elements in the various drawings will be given the same reference numerals, and their descriptions will be omitted where appropriate.

[0041] (Implementation Method)

[0042] The following describes the laser processing apparatus according to embodiments of this disclosure in detail.

[0043] <Structure of Laser Processing Equipment>

[0044] First, use Figure 1 The structure of the laser processing apparatus 1 according to the embodiments of this disclosure will be explained.

[0045] Figure 1 This is a schematic diagram showing the structure of the laser processing apparatus 1 of this embodiment.

[0046] like Figure 1 As shown, the laser processing apparatus 1 of this embodiment includes: a processing head 2, an optical interferometer 3, a measurement and processing unit 4, a laser oscillator 5, a control unit 6, a first driver 7, a second driver 8, etc.

[0047] The optical interferometer 3 emits measurement light 15 for OCT measurement. The emitted measurement light 15 is input to the processing head 2 through the measurement light inlet 9 provided on the second reflector 17.

[0048] The laser oscillator 5 oscillates to generate a processing laser 11 for laser processing. The oscillated processing laser 11 is input into the processing head 2 from the processing light inlet 10.

[0049] The processing laser 11 input to the processing head 2 is transmitted through the dichroic mirror 12 and reflected by the first reflecting mirror 13. The reflected processing laser 11 is transmitted through the lens 14 and focused onto the surface of the workpiece 18, i.e., the processing surface 19. As a result, the processing point 20 on the processing surface 19 of the workpiece 18 is processed by the laser. At this time, the processing point 20 irradiated by the processing laser 11 melts, forming a molten pool 21. Furthermore, molten metal evaporates from the formed molten pool 21. As a result, the pressure of the vapor generated during the evaporation of the molten metal forms a small hole 22 in the workpiece 18.

[0050] On the other hand, the measurement light 15 input to the processing head 2 is converted into parallel light by the collimating lens 16 and reflected by the second reflecting mirror 17. Then, the measurement light 15 is reflected by the dichroic mirror 12 and then by the first reflecting mirror 13. The reflected measurement light 15 passes through the lens 14 and is focused on the processing point 20 of the processing surface 19 of the workpiece 18. The focused measurement light 15 is reflected by the bottom surface of the pinhole 22 and returns to the above propagation path, reaching the optical interferometer 3. At this time, the measurement light 15 performs optical interference with a reference light (not shown) in the optical interferometer 3, generating an optical interference signal.

[0051] The measurement and processing unit 4 measures the depth of the pinhole 22, i.e., the melting depth of the processing point 20, based on the optical interference signal generated in the optical interferometer 3. Here, the "melting depth" refers to the distance between the highest point of the molten portion of the workpiece 18 and the processing surface 19.

[0052] Furthermore, generally, the wavelength of the processing laser 11 is different from the wavelength of the measuring light 15. Specifically, when a YAG laser or fiber laser is used as the processing laser 11, the wavelength of the processing laser 11 is 1064 nm. On the other hand, when an OCT light source is used as the measuring light 15, the wavelength of the measuring light 15 is 1300 nm.

[0053] Furthermore, the dichroic mirror 12 described above has the characteristic of transmitting light of the wavelength of the processing laser 11 and reflecting light of the wavelength of the measuring light 15.

[0054] The first reflector 13 and the second reflector 17 include movable reflectors capable of rotating along two or more axes. The first reflector 13 and the second reflector 17 are, for example, current mirrors. Furthermore, the aforementioned two axes are, for example, equivalent to... Figure 1The x-axis and y-axis are shown in the middle.

[0055] The first reflector 13 and the second reflector 17 are connected to the control unit 6 via the first driver 7 and the second driver 8, respectively, and operate based on the control of the control unit 6. Specifically, the first driver 7 operates the first reflector 13 based on the instruction from the control unit 6. The second driver 8 operates the second reflector 17 based on the instruction from the control unit 6.

[0056] The control unit 6 includes a memory 31. The memory 31 stores processing data for performing desired processing on the workpiece 18, and correction data for making corrections as described later.

[0057] In addition, Figure 1 In the illustration, as an example, only the rotational motion centered on the y-axis is shown for the first reflector 13 and the second reflector 17 (see the dotted line portion and the two arrows in the illustration). However, in reality, the first reflector 13 and the second reflector 17 are configured as described above to be capable of rotational motion along two or more axes. Therefore, the first reflector 13 and the second reflector 17 can also, for example, perform rotational motion centered on the x-axis (see arrow x in the illustration).

[0058] To simplify the explanation, the following describes the case where the first reflector 13 and the second reflector 17 each rotate only around the rotation axis in the y direction (see arrow y in the figure).

[0059] When the second reflecting mirror 17 is at the origin position, such as Figure 1 As shown, the measuring optical axis 23 of the measuring light 15 is reflected by the dichroic mirror 12 and is aligned with the processing optical axis 24 of the processing laser 11.

[0060] Furthermore, when the first reflecting mirror 13 is at the origin position, such as Figure 1 As shown, when the processing optical axis 24 of the processing laser 11 is reflected by the first reflecting mirror 13 and transmitted through the lens 14, it is aligned with the center of the lens 14, i.e., the lens optical axis 25.

[0061] Furthermore, the position of the processing laser 11 at the center of the transmission lens 14 and the position of the measuring light 15 reaching the processing surface 19 of the workpiece 18 (corresponding to the irradiation position) will be referred to as the "processing origin 26" (see reference). Figure 2 To illustrate, the origin positions of the first reflector 13 and the second reflector 17 are the positions of the centers of the processing laser 11 and the transmission lens 14 of the measuring light 15.

[0062] Lens 14 is used to focus the processing laser 11 and the measuring light 15 onto the processing point 20. Lens 14 is, for example, an fθ lens.

[0063] The first reflecting mirror 13 and the lens 14 constitute a general optical scanning system based on a current mirror and an fθ lens. Therefore, by rotating the first reflecting mirror 13 from the origin position by a predetermined angle, the arrival position of the processing laser 11 on the processing surface 19 can be controlled. Hereinafter, the angle by which the first reflecting mirror 13 is rotated from the origin position will be referred to as the "operation amount of the first reflecting mirror 13". In addition, if the positional relationship of each optical component constituting the processing head 2 and the distance from the lens 14 to the processing surface 19 are determined, the operation amount of the first reflecting mirror 13 can be uniquely set. As a result, the processing laser 11 can be directed to the desired processing point 20.

[0064] At this point, it is preferable to set the distance from lens 14 to processing surface 19 such that the focal point of the processing laser 11 is most focused on the processing surface 19. This allows for the most efficient processing of the workpiece 18 based on the processing laser 11. However, the distance from lens 14 to processing surface 19 is not limited to this; any appropriate distance can be determined depending on the application of the processing.

[0065] Furthermore, the first reflector 13 varies its movement according to a predetermined schedule. As a result, the processing laser 11 can scan and irradiate any processing point 20 on the processing surface 19.

[0066] Furthermore, the control unit 6 controls the switching of the laser oscillator 5 on and off. This allows laser processing to be performed on any position on the processing surface 19 within the scannable range of the processing laser 11, using any pattern.

[0067] <Based on the Influence of Color Difference>

[0068] Next, use Figure 2 The effects of chromatic aberration caused by lens 14 will be explained.

[0069] Figure 2 This is a schematic diagram of a laser processing apparatus 1 in which the first reflecting mirror 13 is moved from its origin position. Additionally, in Figure 2 In the middle, the second reflecting mirror 17 is set to the origin position.

[0070] like Figure 2 As shown, the processing laser 11 and the measuring light 15, reflected by the first reflecting mirror 13, travel along the same optical axis until they reach the lens 14. However, after the transmission lens 14, the travel directions of the processing laser 11 and the measuring light 15 deviate. That is, as... Figure 2As shown, the optical axis of the processing laser 11, i.e., the processing optical axis 24a, deviates from the optical axis of the measuring light 15, i.e., the measuring optical axis 23a. Therefore, the measuring light 15 reaches a position different from the processing point 20.

[0071] This is due to the chromatic aberration of lens 14. Chromatic aberration refers to the aberration that occurs when the general optical materials containing lens 14 have different refractive indices for different wavelengths of light.

[0072] Chromatic aberration includes two types: on-axis chromatic aberration and magnification chromatic aberration. On-axis chromatic aberration is an aberration caused by the difference in focal position of the lens depending on the wavelength of light. On the other hand, magnification chromatic aberration is an aberration caused by the difference in image height at the focal plane (processed surface 19) depending on the wavelength of light. Furthermore, Figure 2 The deviation between the direction of travel of the processing laser 11 (processing optical axis 24a) transmitted through the lens 14 and the measuring light 15 (measuring optical axis 23a) is caused by the aforementioned magnification chromatic aberration.

[0073] At this time, axial chromatic aberration also occurs in the laser processing apparatus 1 of this embodiment. However, by adjusting the distance between the collimating lens 16 and the measurement light inlet 9, the deviation between the processing laser 11 and the measurement light 15 caused by axial chromatic aberration can be addressed. In other words, by using the collimating lens 16, the transmitted measurement light 15 is set from a parallel light state to a slightly divergent or convergent state, thereby suppressing the generation of axial chromatic aberration.

[0074] In addition, Figure 2 In this case, from the perspective of the processing origin 26, the position where the measuring light 15 reaches the processing surface 19 is farther than the position where the processing laser 11 reaches the processing surface 19. However, the above positional relationship is just one example. In other words, depending on the lens structure of the lens 14 and the wavelength relationship between the processing laser 11 and the measuring light 15, it is also possible that the measuring light 15 reaches a position closer to the processing origin 26 than the processing laser 11. Generally, longer wavelength light reaches positions farther away from the processing origin 26.

[0075] Furthermore, as a method to correct the aforementioned magnification chromatic aberration, there are methods that give lens 14 the properties of an achromatic lens. However, to give lens 14 both the properties of an fθ lens and the properties of an achromatic lens requires a very high level of optical design skill. Therefore, the design of lens 14 involves a significant amount of time and cost.

[0076] Therefore, in the laser processing apparatus 1 of this embodiment, as described below, the second reflector 17 is moved to achieve magnification chromatic aberration correction at low cost.

[0077] <Methods for Correcting Color Difference Based on Magnification>

[0078] Next, use Figure 3 The method for correcting the magnification chromatic aberration of the lens 14 described above will be explained.

[0079] Figure 3 This is a schematic diagram of a laser processing apparatus 1 in which the deviations in the arrival positions of the processing laser 11 and the measuring light 15 caused by magnification color difference are corrected.

[0080] exist Figure 3 In this process, the second reflecting mirror 17 is moved from its origin position by a specified amount of motion (motion angle). Thus, as... Figure 3 As shown, during the period from the dichroic mirror 12 to the lens 14, the processing optical axis 24 of the processing laser 11 and the measuring optical axis 23 of the measuring light 15 are not coaxial. However, after passing through the lens 14, the processing laser 11 and the measuring light 15 reach the same position on the processing surface 19, namely the processing point 20.

[0081] At this time, as Figure 3 As shown, the processing optical axis 24a of the processing laser 11 passes through and... Figure 2 The processing optical axis 24a is located at the same position as shown. On the other hand, the measuring optical axis 23b of the measuring light 15, which is corrected by the operation of the second reflecting mirror 17 described above, passes through the same position as... Figure 2 The measurements show different positions of the optical axis 23a.

[0082] Furthermore, the amount of motion of the second reflector 17 (i.e., the angle by which the second reflector 17 rotates from the origin position) is established in a one-to-one correspondence with the amount of motion of the first reflector 13. At this time, the amount of motion of the first reflector 13 is uniquely determined based on the position of the machining point 20. Therefore, the amount of motion of the second reflector 17 is also uniquely determined based on the position of the machining point 20.

[0083] Furthermore, the amount of movement of the second reflector 17 will be referred to as the "correction angle" (corresponding to the "second indicator value" described later), and the method for obtaining the correction angle will be explained.

[0084] <Relationship between correction angle and scan angle>

[0085] Next, the relationship between the correction angle of the second reflector 17 and the scanning angle of the first reflector 13 will be explained.

[0086] Here, the focal distance of lens 14 is set as f, the angle between the incident light from lens 14 and the optical axis 25 is set as θ, and the distance from the optical axis to the image plane of the transmitted light from lens 14 (hereinafter referred to as "image height") is set as h. In this case, the relationship h = fθ holds true in the fθ lens, i.e., lens 14.

[0087] Furthermore, as described above, the first reflector 13 has two axes for rotational movement.

[0088] Therefore, assuming the two axes are the x-axis and y-axis, the angle between the light reflected by the first reflecting mirror 13 and the x-axis component of the lens optical axis 25 is set as θx, and similarly, the angle between the light reflected by the first reflecting mirror 13 and the y-axis component of the lens optical axis 25 is set as θy. Furthermore, when the image heights in the x and y directions of the image plane are set as x and y respectively, the relationships x = fθx and y = fθy hold. Thus, if the position of the processing laser 11 reaching the processing surface 19 is set as (x, y), then (x, y) = (fθx, fθy).

[0089] Furthermore, the exit angle of the reflected light from the mirror when light is incident on the mirror is changed by a factor of 2. Therefore, the actuation amount of the first mirror 13 is set to... In this case, The relationship is established. Furthermore, in the following explanation, the motion of the first reflecting mirror 13 will be... This is recorded as the "scan angle" (corresponding to the "first indication value" described later).

[0090] As described above, in the laser processing apparatus 1 of this embodiment, if the scanning angle of the first reflecting mirror 13 is determined... The position (x, y) of the processing point 20, which is the position reached by the processing laser 11 on the processing surface 19, is also determined.

[0091] As described above, the scanning angle is uniquely determined based on the position of the machining point 20. Similarly, the correction amount of the second reflector 17 is also uniquely determined based on the position of the machining point 20.

[0092] Therefore, in this embodiment, the relationship between the scanning angle and the correction amount is pre-calculated according to the position of each predetermined processing point 20. Thus, during processing, the correction amount corresponding to the position of the processing point 20 is adjusted by moving the second reflector 17. This corrects the deviation between the irradiation position of the measuring light 15 and the irradiation position of the processing laser 11 caused by the magnification chromatic aberration of the lens 14.

[0093] <Corrected data table>

[0094] Next, the data in the correction table will be explained.

[0095] The correction table data represents the correspondence between the scan angle and the correction angle at each processing point 20 (an example of processing data for completing the correction).

[0096] First, use Figure 4 The trajectories of the processing laser 11 and the measuring light 15 on the processing surface 19 of the workpiece 18 are explained.

[0097] Figure 4 This diagram schematically illustrates the trajectories of the processing laser 11 and the measurement light 15 on the processing surface 19 of the workpiece 18 when only the first mirror 13 is activated without the second mirror 17, in order to scan the processing surface 19 of the workpiece 18 in a grid pattern.

[0098] in addition, Figure 4 This indicates the state of the machined surface 19 as viewed from the lens 14 side. Figure 4 The solid line represents the trajectory of the processing laser 11, i.e., the processing light trajectory 28, and the dashed line represents the trajectory of the measuring light 15, i.e., the measuring light trajectory 27.

[0099] exist Figure 4 In the example shown, since the second reflecting mirror 17 is not activated, the trajectories of the processing laser 11 and the measuring light 15 are represented without correction for magnification chromatic aberration. Therefore, near the processing origin 26, the trajectories of the processing laser 11 and the measuring light 15 are consistent. However, due to magnification chromatic aberration, the deviation between their trajectories increases with distance from the processing origin 26. In other words, the processing light trajectory 28 depicts a lattice pattern without distortion. On the other hand, the measuring light trajectory 27 depicts a distorted pincushion-shaped trajectory. Furthermore, Figure 4 The shape of the measuring light trajectory 27 shown is an example. In other words, the deformed shape of the measuring light trajectory 27 varies according to the optical properties of the lens 14.

[0100] Furthermore, the deviations in the positions corresponding to the processing light trajectory 28 and the measurement light trajectory 27 also depend on the optical characteristics and optical design of the lens 14. As a general example, in the case of a commercially available fθ lens with a focal distance of 250 mm and a processing surface area of ​​approximately 200 mm in diameter, the trajectory of the processing laser 11 and the measurement light 15 will deviate by 0.2 mm to 0.4 mm near the outermost periphery of the processing surface area.

[0101] In contrast, although the small hole 22 is generated by irradiating the processing point 20 with the processing laser 11 (for example, see reference 20), Figure 1 The diameter of the aperture 11 also depends on the power of the processing laser, spatial coherence, and focusing ability of the lens 14, but it is relatively small, approximately 0.03 mm to 0.2 mm. Therefore, due to the chromatic aberration of the lens 14, the position of the processing laser 11 and the measuring light 15 may be offset, and the measuring light 15 may not reach the bottom surface of the aperture 22. As a result, the accurate melting depth cannot be determined by the measuring light 15.

[0102] In addition, Figure 4In this illustration, a 4×4 grid pattern with equal intervals is used as an example, but this disclosure is not limited to this. The grid pattern used for scanning can also be set with a finer unit number. Furthermore, in relation to the magnification and chromatic aberration characteristics of the fθ lens, particularly in areas requiring precision, the grid spacing of the grid pattern can be narrower. Further, a radial grid pattern can also be used. However, in this embodiment, the correction angle is set using both the x-axis and y-axis, which is therefore more preferable. Figure 4 The pattern shown is an orthogonal lattice.

[0103] Therefore, if for Figure 4 By comparing the processing light trajectory 28 shown with the measurement light trajectory 27, it can be seen that a deviation occurs at each grid point in the grid pattern.

[0104] In other words, in order to generate the correction data, it is necessary to determine the correction amount so that a certain grid point on the processing light trajectory 28, namely the processing light grid point 30, is consistent with the corresponding measurement light grid point 29 on the measurement light trajectory 27.

[0105] <Method for calculating the correction angle>

[0106] Next, use Figure 5 The method for calculating the correction angle at the specified grid point position is explained.

[0107] Figure 5 This is a flowchart illustrating the calculation method for the correction angle at a specified processing grid point 30.

[0108] For simplicity, the following explanation will state that the x-axis of the first reflecting mirror 13 coincides with the x-axis of the second reflecting mirror 17, and the y-axis of the first reflecting mirror 13 coincides with the y-axis of the second reflecting mirror 17. Furthermore, the scanning angle of the first reflecting mirror 13 will be described as ( The correction angle of the second reflecting mirror 17 is defined as (ψx, ψy).

[0109] like Figure 5 As shown, firstly, the control unit 6 of the laser processing apparatus 1 sets the processing light grid point 30 (an example of the target position) for obtaining the correction angle (step S1).

[0110] Next, the control unit 6 selects the axis of the desired correction angle (step S2).

[0111] Specifically, for example, in Figure 4 In the grid pattern shown, choose either the x-axis or the y-axis. The following example illustrates the case where the y-axis is selected as the axis for the desired correction angle. Alternatively, if the x-axis is selected, the explanation below will simply interchange the x-axis and y-axis.

[0112] Next, the control unit 6 moves along an axis orthogonal to the axis of the selected correction angle, for example... Figure 6 As shown, the processing range Wx of the processing light grid point 30 is set (step S3).

[0113] Figure 6 This is a diagram schematically illustrating an example of the machining interval Wx and data acquisition interval Mx (described in detail later) set when the y-axis is selected as the axis of the desired correction angle. Specifically, for example, in step S3, as... Figure 6 As shown, the machining interval Wx of the machining grid point 30 in the x-axis direction orthogonal to the selected y-axis is set. Therefore, the motion plan of the first reflector 13 during machining execution is determined.

[0114] Next, within the set processing range Wx, the control unit 6 sets a data acquisition range Mx (an example of a measurement range) centered on the processed optical grid point 30 (step S4). Specifically, for example, in step S4, as... Figure 6 As shown, within the set processing range Wx, a data acquisition range Mx is set with the processing light grid point 30 as the center.

[0115] Next, the control unit 6 sets multiple data acquisition positions 38 perpendicular to the processing direction within the set data acquisition range Mx (step S5). Specifically, for example, in step S5, such as... Figure 6 As shown, within the set data acquisition interval Mx, data acquisition positions 38 (38a, 38b, 38c) are set in the y-axis direction, which is orthogonal to the processing direction (the direction of the processing interval Wx, for example, the x-axis direction).

[0116] At this time, scanning in the direction perpendicular to the processing direction of the data acquisition position 38 (e.g., the y-axis direction) is performed solely by the movement of the second mirror 17. Furthermore, the scanning range of the second mirror 17 is not dependent on the data acquisition position 38. In other words, the position of the processing direction of the data acquisition position 38 is determined by the position of the first mirror 13 during processing. Therefore, the movement plan of the second mirror 17 is determined such that, for example, the following... Figure 7 As shown, the action is performed only when the specified data acquisition position 38 is reached.

[0117] Figure 7 This is a diagram that schematically illustrates the relationship between processing point 20 and data acquisition location 38 during processing.

[0118] like Figure 7As shown, the data acquisition position 38 is a trajectory on the small hole 22 orthogonal to the processing direction (e.g., the x-axis direction). Furthermore, the positional relationship between the processing point 20 in the processing direction and the data acquisition position 38 is the same, except for the effect of the positional offset between the processing laser 11 and the measuring light 15 caused by the magnification chromatic aberration of the lens 14. Therefore, Figure 6 The data acquisition positions 38a, 38b, and 38c shown are almost identical (including identical) positions on the small hole 22 in the machining direction.

[0119] In addition, Figure 6 The illustration shows the case where the data acquisition position 38 is set to three positions: data acquisition position 38a, data acquisition position 38b, and data acquisition position 38c. However, it is actually preferable to set more than three data acquisition positions 38.

[0120] Furthermore, the scanning range in the direction perpendicular to the processing direction of the data acquisition position 38 is preferably set as follows. Specifically, firstly, the correction angle of the measurement light 15 located at the processing light grid point 30 is determined through optical simulation. Then, the scanning range of the data acquisition position 38 is set with the determined correction angle as the center. Thus, Figure 7 The difference between the position of machining point 20 in the machining direction and the position of data acquisition position 38 is the difference between the correction angle obtained through optical simulation and the actual correction angle. As a result, the position of the small hole 22 can be determined at a position closer to machining point 20.

[0121] The following uses Figures 8 to 11 This explains why the data acquisition position is set in the direction perpendicular to the processing direction.

[0122] Here, the position of the aperture 22 coincides with the position of the processing point 20 of the processing laser 11. In other words, for example, if the center position of the shape of the aperture 22 at the processing light grid point 30 is determined, the measuring light 15 can be aligned with the processing light grid point 30.

[0123] Figures 8 to 11 Examples of the measurement results showing the shape of the small hole 22.

[0124] Specifically, Figure 8 This is a diagram illustrating an example of how the shape of the small hole 22 in the x-direction is determined by the laser processing device 1 when the processing direction is +x. Figure 9 This is a diagram illustrating an example of how the shape of the small hole 22 in the x-direction is determined by the laser processing device 1 when the processing direction is -x. Figure 10This is a diagram showing an example of the results of measuring the shape of the small hole 22 in the y direction using the laser processing device 1 when the processing direction is +x. Figure 11 This is a diagram illustrating an example of how the shape of the small hole 22 in the y direction is determined by the laser processing device 1 when the processing direction is -x.

[0125] Figures 8 to 11 The measurement results shown represent the shapes of the small hole 22 at the machining origin 26. Additionally, Figures 8 to 11 The measurement results shown are the average output values ​​obtained by measuring multiple times using a method different from that in this embodiment.

[0126] Here, the vertical axis in the figure represents the depth z of the pinhole 22 as measured by the optical interferometer 3. The horizontal axis in the figure represents the coordinates of the machined surface 19 (in μm).

[0127] First, to determine the center position of the small hole 22, the center position of the shape transversely cut by the depth direction threshold Zth is determined. The result, when the processing direction is +x, is as follows: Figure 8 As shown, the center position x of the small hole 22 in the machining direction is -15μm. On the other hand, when the machining direction is -x, as... Figure 9 As shown, the center position x of the small hole 22 in the machining direction is 5μm. That is, depending on the machining direction, a difference of 20μm is confirmed.

[0128] Furthermore, it is generally known that the shape of the small hole 22 in the machining direction is slightly pulled downwards towards the rear of the machining direction due to the viscosity of the molten metal. Therefore, it is assumed that the above-mentioned difference is due to the deviation of the center position of the small hole 22 caused by the different machining directions.

[0129] Furthermore, when the machining direction is +x, such as Figure 10 As shown, the center position y of the small hole 22 perpendicular to the machining direction is -20μm. On the other hand, when the machining direction is -x, as... Figure 11 As shown, the center position y of the small hole 22 perpendicular to the machining direction is -20μm. That is, it can be confirmed that the center position y of the small hole 22 is reproduced (the same) regardless of the machining direction.

[0130] In other words, by measuring the shape of the small hole 22 perpendicular to the processing direction, the position of the small hole 22 can be determined with higher accuracy. Therefore, in this embodiment, the data acquisition position 38 is set in the direction perpendicular to the processing direction.

[0131] Next, the control unit 6 performs machining on the machining surface 19 and acquires multiple measurement data (step S6). Furthermore, the multiple measurement data represent the measurement results of each of the multiple data acquisition locations 38.

[0132] For example, when the y-axis is selected, in step S6, in Figure 6 During the processing of the processing interval Wx shown, the measurement data corresponding to positions 38a, 38b, and 38c are acquired. Then, when the processing is completed, a processing mark 39 in the x-axis direction is formed in the processing interval Wx (refer to...). Figure 14 Additionally, when the x-axis is selected, machining marks 39 are formed in the y-axis direction (see reference). Figure 14 ).

[0133] Next, the control unit 6 overlays the acquired measurement data to project it in the processing direction, thus creating projection data (step S7).

[0134] The following uses Figure 12 Here is a specific example of step S7 for creating projection data.

[0135] Figure 12 It is a chart used to illustrate examples where multiple measurement data overlap.

[0136] in addition, Figure 12 Positions a, b, and c shown correspond to respectively Figure 6 The data acquisition locations shown are 38a, 38b, and 38c.

[0137] The vertical axis of the measurement data corresponding to data acquisition positions 38a, 38b, and 38c represents the depth z (vertical axis) measured by the optical interferometer 3, and the horizontal axis represents the correction angle ψy (horizontal axis) of the scanning direction of data acquisition position 38.

[0138] The point clusters in the graphs for locations a, b, and c represent depth data measured using an optical interferometer 3 at each ψy coordinate. For example... Figure 7 As shown, data acquisition position 38 is on the small hole 22, orthogonal to the machining direction. Therefore, the graphs for positions a, b, and c are equal to the results measured on the cross-section orthogonal to the machining direction of the small hole 22.

[0139] At this point, in order to determine the correction angle of the machining grid point 30, the center position of the small hole 22 can be determined based on the chart of position b. However, there is relatively little effective data representing the shape of the small hole 22 in the various point group data. Therefore, the center position of the small hole 22 cannot be determined with sufficient accuracy.

[0140] Furthermore, the data at positions a, b, and c are obtained at different scanning angles of lens 14. Therefore, the ψy coordinates AA, BB, and CC of the center position of the small hole 22 at positions a, b, and c are deviated due to the magnification chromatic aberration of lens 14.

[0141] Here, the magnification color difference can be approximated linearly within a narrow range. Therefore, with the coordinate BB of the position b of the processed light grid point 30 as the center, the distances between coordinates AA and BB are almost the same (including the same).

[0142] Therefore, in this embodiment, by using data that overlaps at the same coordinates (referencing) Figure 12 (Use the chart shown at the bottom) to create point cluster data for each chart at position a, position b, and position c.

[0143] In other words, such as Figure 6 As shown, data acquisition locations 38a, 38b, and 38c are orthogonal to the processing interval Wx. Therefore, Figure 12 The overlapping charts shown are projection data of the charts at positions a, b, and c projected and overlapped in the processing direction.

[0144] At this point, the projection data is the data that overlaps the distribution of point group data at positions a and c, which are equally offset to the left and right, with position b of the processing light grid point 30 as the center. Therefore, the center position P of the projection data is consistent with the coordinate BB of the center position b of the processing light grid point 30.

[0145] Therefore, by determining the center position P of the projection data, the correction angle of the processed light grid point 30 can be obtained. By employing the above method, the effective data for determining the correction angle of the processed light grid point 30 can be increased without being affected by magnification chromatic aberration. This improves the accuracy of the depth measurement of the pinhole 22.

[0146] Next, the control unit 6 calculates the correction angle of the selected axis based on the above projection data.

[0147] The following uses Figure 13 Let's illustrate step S8 with a specific example. Figure 13 It is a diagram used to illustrate an example of determining the correction angle based on projection data.

[0148] Typically, the pinhole 22 is formed by the pressure of the vapor generated during the evaporation of molten metal, and therefore its shape is constantly changing. Thus, Figure 13The point cluster data in the chart becomes a distribution extending in the depth z direction. At this point, the bottom of hole 22 is at the deepest position. Therefore, the area near the lowest point of the point cluster data is extracted. Thus, the shape distribution 40 of the data acquisition location 38 can be obtained.

[0149] Specifically, for example, in the correction angle ψy-axis direction, processing is performed to extract the 5% of data with smaller z values ​​from the point group data existing within a certain interval in the correction angle ψy-axis direction. This yields the shape distribution 40 of the data acquisition position 38. Furthermore, the center position P of the two points of the obtained shape distribution 40 of the data acquisition position 38 with respect to the threshold Zth in the transverse depth direction is determined. This allows the determination of the correction angle of the y-axis of the processed light grid point 30.

[0150] Next, the control unit 6 determines whether to obtain the correction angles for the x-axis and y-axis of the first reflector 13 and the second reflector 17 during their rotation (step S9). If both x-axis and y-axis data are obtained (yes in step S9), the process ends.

[0151] On the other hand, if neither the x-axis nor the y-axis data is obtained (No in step S9), the process returns to step S2. Specifically, for example, if the y-axis is selected in step S2, and the correction angle for the y-axis is calculated in step S8, the process returns to step S2, where the x-axis is selected. Then, the correction angle for the x-axis is calculated in steps S3 to S8.

[0152] Through the above process, the scanning angle of the specified processing lattice point 30 can be obtained. The correction angle (ψx, ψy) in the equation.

[0153] Furthermore, after the above process is completed, such as Figure 14 As shown, on the machining surface 19, a cross-shaped machining mark 39 is formed where the machining light grid points 30 intersect.

[0154] In other words, the above method can determine the correction angle of the processed optical lattice point 30 with an accuracy of less than 10 μm.

[0155] Therefore, in the processing head 2 of this disclosure, the above method is suitable when using a laser with excellent beam quality (e.g., a single-mode fiber laser). In other words, in the case of a single-mode fiber laser, the beam diameter at the processing point 20 of the processing laser 11 is 50 μm or less. Therefore, the above method, which achieves a correction angle accuracy of 10 μm or less in the processing lattice point 30, is also more effective when using a single-mode fiber laser.

[0156] <Method for creating modified data tables>

[0157] Next, use Figure 15 This section explains the method for creating the corrected data table. Figure 15 This is a flowchart illustrating the method for creating modified numerical data tables.

[0158] like Figure 15 As shown, firstly, the control unit 6 of the laser processing apparatus 1 sets the range for laser processing of the processing surface 19 of the temporary workpiece 18 (e.g., a metal plate), i.e., the grid pattern (e.g., ...). Figure 4 The processing light trajectory 28 shown (step S11). Then, select one of the multiple grid points contained in the grid pattern.

[0159] Next, control unit 6 uses Figure 5 The method shown calculates the correction angle based on measurement data in the direction perpendicular to the processing direction (step S12).

[0160] Next, the control unit 6 saves the correction angle obtained in step S12 and the current scanning angle as correction table data in the memory 31 (step S13).

[0161] Next, the control unit 6 checks all grid points of the grid pattern set in step S11 to determine whether the correction table data has been saved (step S14). If the correction table data has been saved in all grid points (yes in step S14), the control unit 6 ends the process.

[0162] On the other hand, if the correction table data is not saved in all the grid points (No in step S14), the control unit 6 selects a new grid point (i.e., the grid point where the correction table data has not been saved) (step S15). Then, the control unit 6 returns the process to step S12 and performs the following steps.

[0163] The corrected data table can be obtained by using the methods described above.

[0164] Furthermore, through the execution of the above methods, such as Figure 16 As shown, this corresponds to all processed optical lattice points 30 (reference). Figure 4 Multiple cross-shaped machining marks 39 are formed on the machining surface 19.

[0165] In addition, the grid pattern set in step S11 is Figure 4 In the case of the 4×4 grid pattern shown, only correction table data with 16 grid points can be generated. Therefore, as described above, it is more preferable to set a grid pattern with more than 16 grid points. This allows for the generation of more correction table data.

[0166] Even with a large number of correction data tables, the scanning angle of the first reflector 13 can be set to any value if it is within the operating range of the mechanism. Therefore, it is possible for the scanning angle of the first reflector 13 to be inconsistent with the correction data tables. In this case, interpolation processing of the correction data tables is required to obtain the correction angle.

[0167] The following describes the method of obtaining the correction angle by performing difference processing on the data in the above correction table.

[0168] <Processing Data>

[0169] Next, the processing data used in the processing of workpiece 18 will be explained.

[0170] Conventionally, the control unit of a laser processing apparatus equipped with an fθ lens and a current mirror controls the laser oscillator and the current mirror using multiple processing data sets configured in a time sequence. This allows for the processing of each processing point on the surface of the workpiece in a time sequence. Furthermore, the aforementioned processing data includes, for example, data items such as the output indication value to the laser oscillator, the scanning angle, and the processing speed, grouped according to each processing point. Here, the output indication value represents the oscillation intensity of the laser used for processing.

[0171] However, in this embodiment, the data items used as processing data in the laser processing apparatus 1 include, in addition to the output indication value to the laser oscillator 5 (laser output data), the position of the processing point 20 (processing point position), and the scanning angle, a correction angle is also added. Furthermore, in the following description, the processing data in which the correction angle is added as a data item will be described as "processing data with correction completed".

[0172] The following uses Figure 17 Here is an example of the corrected processing data described above. Figure 17 This is a diagram illustrating an example of the structure of the corrected processing data.

[0173] like Figure 17 As shown, the corrected processing data is presented as a set of data items, including data number k and laser output data L. k Processing point location x k Location of processing point y k Scanning angle Scan angle Correction angle ψx k Correction angle ψy k .

[0174] Data number k indicates the order of the processing data. Laser output data L k This indicates the output indication value to laser oscillator 5. Processing point position x kThis indicates the position of machining point 20 in the x-direction. Machining point position y k This indicates the position of machining point 20 in the y-direction. (Scan angle) This indicates the scanning angle of the first reflecting mirror 13, which bears the load of scanning in the x-direction. Scanning angle This represents the scanning angle of the first reflecting mirror 13, which bears the y-direction scan. Correction angle ψx k The correction angle ψy represents the correction angle of the second reflecting mirror 17 for the position of the measuring light 15 in the x-direction. k The correction angle of the second reflecting mirror 17 indicates the correction of the position of the measuring light 15 in the y-direction.

[0175] In addition, Figure 17 In this context, the suffix 'k' appended to each data item other than data number 'k' indicates the data item corresponding to the k-th data number. An example of the scan angle in the corrected machining data being the first indicated value. An example of the correction angle in the corrected machining data being the second indicated value.

[0176] As explained above, this constitutes the complete and corrected processing data.

[0177] The following uses Figure 18 The method for creating the processing data (the revised processing data) is explained. Figure 18 It is a flowchart showing the method for creating processing data.

[0178] like Figure 18 As shown, the control unit 6 of the laser processing apparatus 1 first sets the reference data number k to zero (0) (step S21). In addition, the data number k is attached to the area in the memory 31 where the processing data is stored.

[0179] Next, the control unit 6 sets (saves) the laser output data L in the region (memory location) of data number k in the memory 31. k Processing point location x k y k (Step S22). These values ​​are settings set by the user of the laser processing apparatus 1 using an operation unit (e.g., keyboard, mouse, touch panel, etc.) not shown to achieve the desired laser processing.

[0180] Next, the control unit 6 will determine the machining point position x set in step S22. k y k Calculate the scanning angle of the first reflecting mirror 13. The scanning angle The area of ​​data number k stored in memory 31 (step S23). At this time, when the focal distance of lens 14 is f, there exists a gap between the processing point position and the scanning angle. Therefore, the scanning angle is automatically determined based on the location of the processing point.

[0181] Furthermore, the relationship between the machining point position and the scanning angle, as well as the corresponding numerical table, can be preset by the user. In this case, the relationship between the machining point position and the scanning angle, as well as the corresponding numerical table, can be used to further determine the scanning angle of the first reflecting mirror 13.

[0182] Next, the control unit 6 determines whether the setting of processing data is complete for all data numbers k (step S24). At this time, if the setting of processing data is complete for all data numbers k (yes in step S24), the control unit 6 ends the process.

[0183] On the other hand, if the setting of processing data for all data numbers k is not completed (No in step S24), the control unit 6 increments the referenced data number k by one (step S25). Then, the control unit 6 returns the process to step S22 and executes the following steps.

[0184] Based on the above, for all data number k, we can set the data that can be processed (the processed data that has been corrected).

[0185] <Method for setting the correction angle>

[0186] Next, use Figure 19 as well as Figure 20 To explain the purpose of passing Figure 18 The method of setting the correction angle (second indication value) for each processing point position based on the processing data set in the process flow.

[0187] First, use Figure 19 The structure of the correction table data for the processing position is explained. Figure 19 This is a diagram representing the correction table 34 for the processing position, which schematically represents the structure of the correction table data for the processing position.

[0188] in other words, Figure 19 The corrected machining data, set for each grid point in the machining surface 19, is schematically represented as data point 32. As described above, the corrected machining data, i.e., each data point 32, includes the position on the machining surface 19 (i.e., the machining point position), the scanning angle, and the correction angle. Furthermore, Figure 19 The correction data point 33 shown is the point corresponding to the machining origin 26 on the machining surface 19.

[0189] In the following description, for convenience, the positions of each data point 32 in the correction table 34 for the machining position are represented as scanning angles. Furthermore, the scanning angle The data number corresponding to the direction is denoted as i, and the scanning angle is... The data number corresponding to the direction is denoted as j.

[0190] At this time, each data point 32 maintains the correction table using the scan angle (Φx) i ,Φy j The correction angle (Ψx) is used in the table of correction values. ij Ψy ij The group is (Φx) i ,Φy j Ψx ij Ψy ij In other words, the correction table uses the scan angle (Φx) i ,Φy j It has a scanning angle The elements.

[0191] Next, use Figure 20 The method for setting the correction angle (second indicator value) will be explained. Figure 20 This is a flowchart illustrating the method for setting the correction angle.

[0192] like Figure 20 As shown, the control unit 6 first sets the reference data number k to zero (0) (step S31).

[0193] Next, the control unit 6 stores the scan angle in the region of data number k in the memory 31. All correction values ​​in Table 34 for machining position are represented by the scan angle (Φx). i ,Φy j The comparison is performed. Furthermore, control unit 6 determines whether... and The data numbers i and j are determined in step S32. Specifically, in step S32, the control unit 6 determines whether there is a data item in the correction table 34 of the processing position that contains a scanning angle that is exactly the same as the scanning angle set by the user.

[0194] At this time, in existence and If the data numbers are i and j (as in step S32), the control unit 6 will proceed to step S33 as described below. On the other hand, if no data numbers are present... and If the data numbers are i or j (no in step S32), the control unit 6 will proceed to step S34.

[0195] Furthermore, in step S33, the control unit 6 uses and For data numbers i and j, the correction angle is set to (ψx).k ψy k )=(Ψx ij Ψy ij That is, in this step S33, since there are data items that contain scanning angles that are exactly the same as the scanning angles set by the user, the control unit 6 directly sets the corresponding correction table as the correction angle.

[0196] Furthermore, in step S34, the control unit 6 uses the scanning angle surrounding the user-set value within the correction table 34. The data from the four closest points are interpolated, and a correction angle (ψx) is set. k ψy k Furthermore, the details of step S34 will be described later.

[0197] Next, the control unit 6 will set the correction angle (ψx) in step S33 or step S34. k ψy k Set (save) the area of ​​data number k of the processing data in memory 31 (step S35).

[0198] Next, the control unit 6 determines whether the setting of the correction angle is complete for all the processing data stored in the memory 31 (step S36). If the setting of the correction angle is complete for all the processing data (yes in step S36), the control unit 6 ends the process.

[0199] On the other hand, if the setting of the correction angle is not completed for all the processing data (No in step S36), the control unit 6 increments the reference data number k by one (step S37). Then, the control unit 6 returns the process to step S32 and executes the following steps.

[0200] Based on the above, in the process of... Figure 18 In the processing data set according to the illustrated process, a correction angle is set for all data numbers k. In other words, the corrected processing data is generated.

[0201] <Details of interpolation processing>

[0202] Next, use Figure 21 ,right Figure 20 The interpolation process in step S34 is explained in detail.

[0203] In addition, the interpolation process in step S34 is performed at the scan angle set by the user. The correction table within data point 32 is scanned using the angle (Φx). i ,Φy j ) Execute if any of them are inconsistent.

[0204] Figure 21 This represents the scan angle X set by the user as processing data. and Figure 19 The correction table for any data point 32 in the correction table 34 of the machining position shown uses the scan angle (Φx) i ,Φy j Inconsistent scanning angle X A graph showing the relationship between the data points and the surrounding corrected data points.

[0205] like Figure 21 As shown, the scanning angle X The corresponding point is located at the point of correction of data point A(Φx) i ,Φy j Ψx ij Ψy ij Corrected data point B (Φx) i+1， Φy j Ψx i+1j Ψy i+1j Corrected data point C(Φx) i ,Φy j+1 Ψx ij+1 Ψy ij+1 Corrected data point D(Φx) i+1 ,Φy j+1 Ψx i+1j+1 Ψy i+1j+1 Within the grid formed by the 4 points of ) . At this time, (The equality sign cannot be true at the same time), The relationship is valid even if the equality signs do not both hold.

[0206] Furthermore, the correction angle (ψx) k ψy k Using scan angle X The values ​​of and the values ​​of the corrected data points A, B, C, and D are obtained by equations (1) and (2) shown below.

[0207] ψx k =(EΨx) ij +FΨx i+1i +GΨx ij+1 +HΨx i+1j+1 ) / J ···(1)

[0208] ψy k =(EΨy ij +FΨy i+1j +GΨy ij+1 +HΨy i+1j+1 ) / J ···(2)

[0209] In addition, E, F, G, H and J in equations (1) and (2) are obtained by equations (3) to (7) as shown below.

[0210]

[0211]

[0212]

[0213]

[0214] J=(Φx i+1 -Φx i )(Φy j+1 -Φy j ) ···(7)

[0215] Through the interpolation process described above, the correction angle can be calculated based on the scan angle set by the user.

[0216] Furthermore, while the above interpolation process used linear interpolation as an example, it is not limited to this. For example, well-known two-dimensional interpolation techniques (spline interpolation, quadratic surface approximation, etc.) can also be used as interpolation methods. Additionally, as interpolation methods, a correction angle (Ψx) can be used in advance based on the correction table 34 for the machining position. ij Ψy ij ), calculate the approximate continuous surface of the higher order of the correction angle relative to the scan angle, and calculate the correction angle corresponding to the scan angle.

[0217] Laser Processing Methods

[0218] Next, use Figure 22 The laser processing method based on laser processing device 1 will be described.

[0219] Figure 22 This is a flowchart illustrating a laser processing method.

[0220] like Figure 22 As shown, firstly, the control unit 6 of the laser processing apparatus 1 sets the reference data number k to zero (0) (step S41).

[0221] Next, the control unit 6 reads the completed machining data (laser output data L) corresponding to data number k from the memory 31. k Scanning angle Correction angle (ψx) k ψy k (Step S42).

[0222] Next, the control unit 6 uses the scan angle of the readout. To make the first reflecting mirror 13 operate, based on the correction angle (ψx) k ψy k This causes the second reflector 17 to operate (step S43).

[0223] Specifically, control unit 6 notifies the first driver 7 of the scanning angle. Therefore, the first driver 7 is based on the scan angle The first reflector 13 is activated. Furthermore, the control unit 6 notifies the second actuator 8 of the correction angle (ψx). k ψy k Therefore, the second driver 8 is based on the correction angle (ψx) k ψy k This causes the second reflecting mirror 17 to operate.

[0224] Next, the control unit 6, based on the read laser output data L, k The processing laser 11 is oscillated by the laser oscillator 5 (step S44).

[0225] Specifically, the control unit 6 will use the laser output data L, which is the laser output value, as the control unit. k The data is sent to laser oscillator 5. Therefore, laser oscillator 5 uses the laser output data L... k The laser 11 for processing is oscillated.

[0226] Next, the control unit 6 determines whether the laser processing corresponding to all data numbers k stored in the memory 31 has ended (step S45). If the laser processing corresponding to all data numbers k has ended (yes in step S45), the control unit 6 ends the process.

[0227] On the other hand, if the laser processing corresponding to all data number k has not been completed (No in step S45), the control unit 6 increases the referenced data number k by one (step S46).

[0228] Then, the control unit 6 returns the process to step S42 and executes the following steps.

[0229] Following the above process, laser processing is performed on all data numbered k.

[0230] <Method for measuring the depth of a small hole>

[0231] Next, use Figure 23 The small hole 22 during the execution of the above-mentioned laser processing method (for example, referring to...) Figure 1 The method for measuring the depth of the object will be explained.

[0232] Figure 23 This is a flowchart illustrating the method for measuring the depth of the small hole 22.

[0233] First, the control unit 6 of the laser processing device 1 starts... Figure 22 Before the laser processing method shown, position data of the processing surface 19 of the unprocessed workpiece 18 is acquired. This position data represents the height of the processing surface 19 in its unprocessed state (in other words, Figure 1 The data shows the position of the machined surface 19 in the z-axis direction (as shown).

[0234] Next, as Figure 23 As shown, the control unit 6 issues a command to the measurement processing unit 4 to start the measurement of the depth of the small hole 22 (step S51).

[0235] Next, if Figure 22 When the laser processing method shown begins, the measurement processing unit 4 causes the measurement light 15 to be emitted from the optical interferometer 3. Furthermore, the measurement processing unit 4 generates an optical interference signal corresponding to the optical path difference between the measurement light 15 reflected back from the aperture 22 and the reference light (step S52).

[0236] Next, the measurement processing unit 4 uses the position data and the generated optical interference signal to calculate the depth of the pinhole 22 (i.e., the penetration depth). Then, the control unit 6 stores the data representing the calculated depth of the pinhole 22 (hereinafter referred to as "pinhole depth data") in the memory 31 (step S53).

[0237] Next, the control unit 6 determines whether to end the measurement of the depth of the small hole 22 (step S54). If the measurement has not ended (no in step S54), the control unit 6 returns the process to step S52 and executes the following steps.

[0238] On the other hand, in the case of ending the measurement (as in step S54), the control unit 6... Figure 22 After the laser processing method shown is completed, the measurement processing unit 4 is given a command to end the measurement of the depth of the small hole 22 (step S55).

[0239] Furthermore, the commands to start measuring the depth of the small hole 22 in step S51 and to end measuring the depth of the small hole 22 in step S55 do not need to be executed by the control unit 6. For example, the commands can be executed by a user using an operation unit (not shown). Thus, for example, the function of controlling the small hole depth measurement and the function of controlling laser processing can be separated. Therefore, the design freedom of the laser processing apparatus 1 is increased.

[0240] <Effect>

[0241] As explained above, in this embodiment, the laser processing apparatus 1 sets a processing interval Wx through the processing light grid points 30 on the processing surface 19. Within the processing interval Wx, a data acquisition interval Mx centered on the processing light grid points 30 is set. Within the data acquisition interval Mx, a trajectory perpendicular to the processing direction, i.e., multiple data acquisition positions 38, is set. Further, during processing in the processing interval Wx, the laser processing apparatus 1 acquires measurement data representing the shape of each small hole 22 at the data acquisition positions 38, and creates projection data that projects and overlaps the measurement data in the processing direction. Based on the projection data, a second indication value (correction angle of the second reflector 17) in the direction perpendicular to the processing direction in the processing light grid points 30 is obtained.

[0242] This structure corrects for the deviation between the arrival position of the processing laser 11 at the processing surface 19 after transmission through the lens 14 and the arrival position of the measurement light 15, caused by the magnification chromatic aberration of the lens 14. Therefore, it is possible to appropriately measure the depth of the pinhole 22 based on the optical interferometer 3. As a result, the depth of the pinhole can be measured more accurately.

[0243] The following uses Figure 24 The correction results for the magnification chromatic aberration of the lens 14 in the laser processing apparatus 1 with the above structure will be explained.

[0244] Figure 24 This is a diagram showing an example of the trajectory of the processing laser 11 and the measuring light 15 at the processing surface 19 under a state that corrects for the magnification chromatic aberration based on the operation of the second mirror 17.

[0245] like Figure 24 As shown, through the above corrections, the trajectory of the processing laser 11 (processing light trajectory 28), the trajectory of the measuring light 15 (measuring light trajectory 27), and the coordinates of each grid point with... Figure 4 Different, yet consistent.

[0246] Furthermore, this disclosure is not limited to the description of the above embodiments, and various modifications can be made without departing from its spirit. Hereinafter, specific examples of modifications will be described.

[0247] [Variation 1]

[0248] In the above embodiment, in order to change the optical axis direction of the measuring light 15, the case of using a current mirror, i.e., the second reflecting mirror 17, is used as an example, but it is not limited to this.

[0249] The second reflector used in the laser processing apparatus 1 may, for example, be structured as follows: positioned between the measurement light inlet 9 and the dichroic mirror 12, and capable of changing the optical axis direction of the measurement light 15 based on the control of the control unit 6, for example... Figure 25The structure of the second reflecting mirror 35 is shown.

[0250] Figure 25 This is a schematic diagram of a laser processing apparatus 1 using the second reflector 35.

[0251] Figure 25 The laser processing device 1 shown replaces Figure 1 The second reflector 17 shown, etc., has a second reflector 35, and further includes a movable stage 36 and a stage driver 37. Additionally, Figure 25 The laser processing device 1 shown does not have Figure 1 Collimating lens 16, as shown.

[0252] The second reflecting mirror 35 is a parabolic reflecting mirror fixed between the measuring light inlet 9 and the dichroic mirror 12. Alternatively, the second reflecting mirror 35 may also include a MEMS (Micro Electro Mechanical Systems) reflecting mirror, etc.

[0253] In addition, the movable stage 36 is set at the light inlet 9 for measurement.

[0254] The table driver 37 is electrically connected to the control unit 6 and, based on instructions from the control unit 6, causes the movable table 36 to move. Thus, the movable table 36... Figure 25 The stage 36 moves in the yz direction (refer to the two arrows pointing up and down in the diagram). That is, the moving direction of the stage 36 is the two-axis direction perpendicular to the measuring optical axis 23.

[0255] Furthermore, the exit end of the measuring light 15 in the measuring light inlet 9 is configured to coincide with the focal point of the second reflecting mirror 35. As a result, the measuring light 15 becomes parallel light after being reflected by the second reflecting mirror 35 and is directed toward the dichroic mirror 12.

[0256] At this time, by moving the movable stage 36, the angle of the measuring optical axis 23 from the second reflecting mirror 35 toward the dichroic mirror 12 changes. Thus, the same effect as when using the current mirror, i.e., the second reflecting mirror 17, can be obtained.

Claims

1. A laser processing apparatus, comprising: A laser oscillator that oscillates to produce a processing laser that irradiates a processing point on the processing surface of the workpiece; An optical interferometer emits measurement light that illuminates the processing point and generates an optical interference signal based on the interference caused by the optical path difference between the measurement light reflected at the processing point and the reference light. The first reflecting mirror causes a change in the direction of travel of the processing laser and the measuring light; The second reflecting mirror causes the incident angle of the measuring light toward the first reflecting mirror to change; A lens that focuses the processing laser and the measuring light onto the processing point; The control unit controls the laser oscillator, the first reflector, and the second reflector based on the corrected processing data. and The measurement processing unit measures the depth of the small hole generated at the processing point by irradiating the processing laser, based on the optical interference signal. The corrected processing data is used to eliminate deviations in the arrival positions of at least one of the processing laser and the measurement light on the processing surface caused by the chromatic aberration of the lens. It includes an output indication value, a first indication value, and a second indication value set for each processing point. The output indication value represents the oscillation intensity of the processing laser, the first indication value represents the amount of movement of the first reflector, and the second indication value represents the amount of movement of the second reflector. The control unit sets the processing range through the target position on the processing surface. The control unit sets a measurement range centered on the target position within the processing range. The control unit sets multiple data acquisition positions, which are perpendicular to the processing direction, within the measurement range. During processing in the processing zone, the control unit acquires measurement data representing the shape of the small hole at each of the data acquisition locations. The control unit generates projection data that superimposes the measured data onto the machining direction. Based on the projection data, the control unit calculates the second indication value in the direction perpendicular to the processing direction at the target position.

2. The laser processing apparatus according to claim 1, wherein, The control unit calculates the second indication value at the target position in the direction perpendicular to the processing direction for each of the x-axis and y-axis axes that rotate the first and second reflectors.

3. The laser processing apparatus according to claim 1 or 2, wherein, The control unit sets a grid pattern on the processing surface. The control unit sets the grid points of the grid pattern as the target positions.

4. The laser processing apparatus according to claim 1 or 2, wherein, The control unit generates and stores the corrected processing data.

5. A laser processing method, wherein the laser processing is performed by a laser processing device. The laser processing apparatus includes: a first reflecting mirror that changes the travel direction of the processing laser and the measurement light; a second reflecting mirror that changes the incident angle of the measurement light toward the first reflecting mirror; and a lens that focuses the processing laser and the measurement light onto a processing point on the processing surface of the workpiece. Based on corrected processing data, the laser processing apparatus controls the first and second reflecting mirrors to irradiate the workpiece with the processing laser and the measurement light. Based on the interference caused by the optical path difference between the measurement light reflected at the processing point and a reference light, the depth of the small hole formed at the processing point by irradiating the processing laser is measured. The corrected processing data is used to eliminate deviations in the arrival positions of at least one of the processing laser and the measurement light on the processing surface caused by the chromatic aberration of the lens. It includes a pre-set output indication value, a first indication value, and a second indication value for each processing point. The output indication value represents the oscillation intensity of the processing laser, the first indication value represents the amount of movement of the first reflector, and the second indication value represents the amount of movement of the second reflector. The laser processing device is configured to process a range through the target position on the processing surface. The laser processing device sets a measurement range centered on the target position within the processing area. Within the measurement range, the laser processing device sets multiple data acquisition positions along a trajectory perpendicular to the processing direction. During processing within the processing area, the laser processing device acquires measurement data representing the shape of the small hole at each of the data acquisition locations. The laser processing apparatus is configured to generate projection data that superimposes the measured data onto the processing direction. The laser processing device calculates the second indication value of the direction perpendicular to the processing direction at the target position based on the projection data.

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