Processing status monitoring device and processing status monitoring method

Abstract

To provide a processing state monitoring device that can improve the accuracy of detecting light from the processing surface during laser processing. [Solution] The processing state monitoring device according to the present disclosure is a device for monitoring the processing state in laser processing, which is performed by irradiating the processing surface of a workpiece with laser light, and comprises at least one photodetector that detects first light that is propagated from a molten region formed around the irradiation spot of the laser light on the processing surface and includes light of a different wavelength from the wavelength of the laser light, and an optical propagation correction element disposed between the processing surface and the at least one photodetector, wherein the optical propagation correction element receives the first light from the molten region and corrects the propagation direction of the first light according to the position of the molten region on the processing surface and emits it to the at least one photodetector.

Description

Technical Field

[0001] The present disclosure relates to a processing state monitoring device and a processing state monitoring method for monitoring a laser processing state.

Background Art

[0002] Laser processing technology is a processing technology that irradiates a workpiece with laser light emitted from a laser oscillator and performs welding, cutting, drilling, marking, surface treatment, etching, deposition, etc. on the workpiece using the heat of the laser light, and is used in a wide variety of fields.

[0003] During laser processing, the processing state can be monitored by detecting the welding light radiated from the molten region on the processing surface, and the quality of the processing can be evaluated in real time. A laser processing device capable of monitoring the processing state is, for example, the processing device disclosed in Patent Document 1.

[0004] The laser processing device of Patent Document 1 is configured to monitor the processing state by propagating light having a plurality of different wavelengths generated on the processing surface of the workpiece during irradiation with the laser light to corresponding optical sensors and detecting them separately.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In recent years, a configuration in which a scanning mechanism is used to scan the laser beam while processing the workpiece surface has been widely adopted in laser processing. However, in the configuration for monitoring the processing state described in Patent Document 1, at processing points near the periphery of the processing surface, the wavelength of the generated light can cause a deviation in the direction of light propagation during propagation from the processing surface to the optical sensor, making it difficult to accurately detect the light. Therefore, there is still room for improvement in the accuracy of detecting light from the processing surface during laser processing in conventional processing state monitoring devices.

[0007] Therefore, this disclosure aims to solve the above-mentioned conventional problems and to provide a processing state monitoring device and a processing state monitoring method that can improve the accuracy of detecting light from the processing surface during laser processing. [Means for solving the problem]

[0008] To achieve the above objective, a processing state monitoring device according to one aspect of the present disclosure is a device for monitoring the processing state in laser processing, which is performed by irradiating a workpiece surface with laser light, and comprises at least one photodetector that detects first light propagating from a molten region formed around the irradiation spot of the laser light on the processing surface and which includes light of a different wavelength from the wavelength of the laser light, and an optical propagation correction element disposed between the processing surface and the at least one photodetector, wherein the optical propagation correction element receives the first light from the molten region and corrects the propagation direction of the first light according to the position of the molten region on the processing surface before emitting it to the at least one photodetector.

[0009] Furthermore, in order to achieve the above objective, a processing state monitoring method according to one aspect of the present disclosure is a method for monitoring the processing state in laser processing performed by irradiating a workpiece surface with laser light, and includes: guiding a first light, which is propagated from a molten region formed around the irradiation spot of the laser light and includes light of a different wavelength from the wavelength of the laser light, to an optical propagation correction element; correcting the propagation direction of the first light in the optical propagation correction element according to the position of the molten region on the processing surface and emitting it to at least one photodetector; and detecting the first light emitted from the optical propagation correction element in at least one photodetector. [Effects of the Invention]

[0010] According to one aspect of this disclosure, the accuracy of detecting light from the processing surface can be improved during laser processing. [Brief explanation of the drawing]

[0011] [Figure 1] A schematic plan view showing an example of the configuration of a laser processing apparatus according to Embodiment 1 of this disclosure. [Figure 2] This diagram conceptually illustrates the deviation in the direction of detected light propagation caused by the position of the molten region on the processed surface, in a processing state monitoring device that does not have a light propagation correction element. [Figure 3] Block diagram showing an example of the configuration of the control device for the processing state monitoring device according to Embodiment 1 of this disclosure. [Figure 4] Flowchart showing the detection light propagation direction correction process of the processing state monitoring device according to Embodiment 1 of this disclosure. [Figure 5] A diagram conceptually illustrating the calculation of the location of the molten region. [Figure 6] This diagram conceptually illustrates how to obtain the propagation direction correction amount by referring to correction reference data. [Figure 7] An example configuration of a laser processing apparatus equipped with a processing state monitoring device according to Embodiment 1 of the present disclosure, the schematic plan view showing the operation of the processing state monitoring device. [Figure 8]Another configuration example of a laser processing apparatus equipped with a processing state monitoring device according to Embodiment 1 of this disclosure, the schematic plan view showing the operation of the processing state monitoring device. [Modes for carrying out the invention]

[0012] The embodiments will be described in detail below, with reference to the drawings as appropriate. However, unnecessarily detailed explanations may be omitted. For example, detailed explanations of already well-known matters and redundant explanations of substantially identical configurations may be omitted. This is to avoid the following explanation becoming unnecessarily verbose and to facilitate understanding for those skilled in the art.

[0013] A machining state monitoring device and a machining state monitoring method according to embodiments of this disclosure will be described with reference to Figures 1 to 8. The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this disclosure and are not intended to limit the subject matter described in the claims. In addition, elements in each figure are exaggerated to facilitate explanation. Substantially identical components in the drawings are denoted by the same reference numerals.

[0014] <Embodiment 1> (Configuration of laser processing equipment) The configuration of the laser processing apparatus according to Embodiment 1 of this disclosure will be described with reference to Figure 1. Figure 1 is a schematic plan view showing an example of the configuration of the laser processing apparatus 100 according to Embodiment 1 of this disclosure.

[0015] The laser processing apparatus 100 shown in the X-Z plane includes a processing system 10, a processing state monitoring device 20, a photodetector 41, and a control system 50. The processing system 10 performs laser processing by irradiating a processing surface of a workpiece 70 with laser light. The processing state monitoring device 20 detects light generated on the processing surface of the workpiece 70 during irradiation of the laser light by the processing system 10. The control system 50 can determine the processing state on the processing surface of the workpiece 70 based on the information of the light detected by the processing state monitoring device 20. Further, the control system 50 can feedback the determination result of the processing state to the processing system 10 according to the application and adjust the irradiation of the laser light. Hereinafter, the components and operations of the laser processing apparatus 100 will be described in detail. In the following, laser welding is taken as an example to describe the laser processing by the laser processing apparatus 100, but the present disclosure is not limited thereto. For example, other laser processing such as cutting and drilling may be performed using the laser processing apparatus 100.

[0016] (Configuration of the processing system) In the present embodiment, the processing system 10 includes a laser oscillator 11 that is a processing light source, a processing control unit 12, a collimating lens 13, a partial reflection mirror 14, a movable mirror 15, and an fθ lens 16. Note that the processing system 10 can further include other optical elements (not shown) such as mirrors, lenses, and light shielding elements according to the application.

[0017] The laser oscillator 11 is composed of, for example, a gas laser such as a carbon dioxide laser, or a solid laser such as a YAG laser, a semiconductor laser, or a fiber laser, and generates laser light with a predetermined wavelength and a predetermined output. As an example, the laser light may be a continuous wave (CW) with a wavelength of 1070 nm, and an optimal laser wavelength can be selected according to the light absorption characteristics of the workpiece 70 for processing. For example, when the workpiece 70 is copper (Cu) or gold (Au), it can be processed with laser light having a relatively short wavelength of 405 nm or more and 450 nm or less. Also, for example, when the workpiece 70 is aluminum, since good welding is possible due to good light absorption characteristics, it can be processed with laser light having a wavelength near 800 nm. Note that the laser light for processing may be continuous wave laser light or pulsed wave laser light. When continuous wave laser light is used, it can be said that the amount of heat input to the workpiece is large and the productivity is high compared to pulsed wave laser light. On the other hand, when pulsed wave laser light is used, the heat influence during processing can be reduced compared to continuous wave laser light.

[0018] The laser oscillator 11 is communicably connected to the processing control unit 12 and can control the laser beam output by the laser oscillator 11 according to commands from the processing control unit 12. For example, the output power of the laser oscillator 11 can be controlled by the processing control unit 12, and in the case of pulsed wave laser light, the output period or duty cycle of the laser oscillator 11 can be controlled.

[0019] The processing control unit 12 is, for example, a computer device. As the computer device constituting the processing control unit 12, a general-purpose computer device can be used, and it can include, for example, a processor such as a central processing operator (CPU) and a storage device such as a hard disk drive (HDD) or a solid-state drive (SSD). Also, the processing control unit 12 may further include a display device, an input / output device, an interface, etc.

[0020] The processing control unit 12 can control the processing laser beam. In this embodiment, the processing control unit 12 is communicatively connected to the laser oscillator 11 and also communicatively connected to the processing stage (not shown) that supports the movable mirror 15 and the workpiece 70, and controls the scanning of the laser beam onto the workpiece 70 and the irradiation pattern of the laser beam.

[0021] The storage device of the processing control unit 12 stores, for example, a laser beam output control program and a laser beam scanning program. The storage device of the processing control unit 12 also stores various processing parameters that define the laser beam irradiation spot. These stored processing parameters may include, for example, the scanning position of the laser beam applied during processing, and a beam pattern that defines the shape and size of the irradiation spot. The processor of the processing control unit 12 controls the output of the laser oscillator 11 by executing the laser beam output control program stored in the storage device. The processor of the processing control unit 12 also controls the operation of the movable mirror 15 and the processing stage by executing the laser beam scanning program, scanning the laser beam across the processing surface. The laser beam is irradiated at predetermined scanning positions on the processing surface with the set beam pattern, and processing is performed. The transmission of commands from the processing control unit 12 to the laser oscillator 11, movable mirror 15, and processing stage may be achieved by wired connection or by wireless transmission.

[0022] The laser beam L11 from the laser oscillator 11 may be emitted, for example, through an optical fiber. The emitted laser beam L11 travels along the optical axis Oa in the direction -Z shown in the figure, passes through the collimating lens 13, and is converted into a parallel light beam. The parallel light beam of laser beam L11 continues to travel in the -Z direction and is incident on the partial reflection mirror 14.

[0023] The partial reflection mirror 14 has the function of reflecting most of the laser light L11 from the collimating lens 13 and transmitting a portion of it. In this embodiment, the partial reflection mirror 14 may be, for example, a dichroic mirror, and may be configured to reflect 90% or more of the light in the wavelength range of the laser light emitted from the laser oscillator 11 and transmit 50% or more of the remaining light in the wavelength range of 350 nm to 2000 nm. Note that this disclosure is not limited to the optical properties of the partial reflection mirror 13. The partial reflection mirror 14 can be configured to have desired optical properties.

[0024] A portion of the laser light L11a that passes through the partial reflection mirror 14 travels in the -Z direction and is received by the photodetector 41. The photodetector 41 includes, for example, a photodiode and an A / D converter, and detects the intensity of a portion of the laser light L11a output from the laser oscillator 11, converting it into an electrical signal S1 such as a voltage or current value. The electrical signal S1 is transmitted to the control system 50 and used to control the irradiation of the laser light. If the output of the laser oscillator 11 is high, an optical element (not shown) that attenuates light may be installed in front of the photodetector 41.

[0025] The remaining portion L11b of the laser beam L11 reflected by the partial reflection mirror 14 travels in the -X direction and is incident on the movable mirror 15. The laser beam L11b is guided to the workpiece 70 and performs machining on the workpiece 70a.

[0026] The movable mirror 15 is connected to the processing control unit 12 in a communicative manner, and by changing its operating angle according to a predetermined operating schedule in response to commands from the processing control unit 12, the laser beam L11b can be scanned over the workpiece 70. This allows for the selection of a desired processing point and the switching of the laser oscillator 11 on and off, enabling laser processing with any beam pattern at any scanning position on the processing surface 70a.

[0027] In this embodiment, the movable mirror 15 may be a galvanometer mirror. The movable mirror 15 can be configured to rotate on two or more axes, for example, it can rotate around a rotation axis in the Y direction shown in the figure, and / or around a rotation axis parallel to the XZ plane shown in the figure.

[0028] The laser beam L11b reflected by the movable mirror 15 is focused by the fθ lens 16 and then irradiated onto the processing surface 70a of the workpiece 70. In the embodiment shown in Figure 1, the laser beam L11b irradiates the processing surface 70a along the optical axis Ob of the fθ lens 16, and a melting region 71 is formed around the irradiation spot in the center of the processing surface 70a. In the melting region 71, a large amount of thermal energy is input by the laser beam L11b, and the portion exceeding the melting point melts, allowing laser processing such as welding or cutting to be performed. The distance between the fθ lens 16 and the processing surface 70a can be adjusted so that the processing surface 70a is at the focusing position of the fθ lens 16, so that processing by the laser beam L11b is performed most efficiently. Note that this disclosure is not limited to the distance from the fθ lens 16 to the processing surface 70a; the position of the processing surface 70a relative to the fθ lens 16 may be adjusted according to the actual application.

[0029] The workpiece 70, which is the object to be processed, may be supported by a processing stage (not shown) composed of, for example, an XYZθ table. The processing stage is also connected to a processing control unit 12 in a communicative manner, and in response to a command from the processing control unit 12, the processing stage moves either together with or with a movable mirror 15 to adjust the three-dimensional relative position and / or relative angle between the workpiece 70 and the beam of the processing laser light L11b, thereby enabling the desired processing.

[0030] The workpiece 70 is a material processed by the laser beam L11b, and may be an iron-based metal such as SPCC or SUS. Furthermore, the workpiece 70 is not limited to iron-based materials, and may also be a non-ferrous metal such as aluminum or copper, or even a brittle material such as resin or ceramic.

[0031] The laser beam L11b is irradiated onto the processing surface 70a of the workpiece 70, forming a molten region 71 around the irradiation spot, and welding light is generated from the molten region 71. The welding light can include, for example, thermal radiation light emitted from the molten region 71 (e.g., light with a wavelength range of 1300 nm to 1550 nm), plasma light (e.g., light with a wavelength range of 400 nm to 700 nm), and reflected light from the laser beam L11b reflected by the workpiece 70 (e.g., light with a wavelength of around 1070 nm). In this embodiment, one or more of these different wavelengths of light contained in the welding light are propagated to the processing state monitoring device 20 and detected. In this embodiment, as shown in Figure 1, the detection light L20, which includes the first detection light L21 and the second detection light L22, is guided to the processing state monitoring device 20, and the first detection light L21 and the second detection light L22 are detected separately by the photodetectors 42 and 43 of the processing state monitoring device 20. The configuration of the processing state monitoring device 20 will be described in detail later.

[0032] In this specification, "detection light" refers to welding light generated in the molten region of the processing surface during laser irradiation, which is guided from the processing surface to the processing state monitoring device and detected. In this specification, the detection light includes light of a different wavelength from the wavelength of the processing laser light, may include light of one wavelength, or may include light of two or more different wavelengths, and includes at least one of light in the infrared wavelength range and light in the visible range emitted from the molten region. In this specification, "detection light" may be referred to as "first light".

[0033] Furthermore, this disclosure is not limited to the number of detection lights that are guided to and detected by the processing state monitoring device. In addition, the photodetectors in the processing state monitoring device 20 only need to be arranged to correspond to the detection lights to be detected.

[0034] (Control system configuration) The control system 50 is, for example, a computer device. A general-purpose computer device can be used as the computer device constituting the control system 50, and may include, for example, a processor such as a central processing unit (CPU) and a storage device such as a hard disk drive (HDD) or SSD. Furthermore, the machining control unit 12 may also include a display device, an input / output device, an interface, etc.

[0035] The control system 50 receives a signal S1 of laser light L11a from the photodetector 41, and also receives signals S2 and S3 of welding light generated in the molten region 71 from the photodetectors 42 and 43. Based on the signal S1 of laser light L11a, for example, the stability of the output of the laser oscillator 11 can be determined. On the other hand, the signals S2 and S3 of welding light from the molten region 71 on the processed surface 70a can reflect the processing state of the workpiece 70. The processor of the control system 50 can, for example, execute a processing state determination program stored in the memory device to determine the processing state of the workpiece 70 based on signals S2 and S3, and perform a quality inspection of the laser processing. Furthermore, in the laser processing apparatus 100 of this embodiment, the control system 50 is further connected to the processing control unit 12 in a communicative manner, and during laser processing, it can send a signal T to the processing control unit 12 to provide feedback on the stability of the laser beam and the processing state of the workpiece, thereby adjusting the laser beam. This reduces processing defects and enables stabilization of the quality of the processed product.

[0036] The control system 50 may be mounted within the laser processing apparatus 100, or it may be provided separately as an external device and connected to the laser processing apparatus in a communicative manner. Furthermore, the transmission and reception of signals by the control system 50 may be achieved by wired connection or by wireless transmission.In this embodiment, the control system 50 is connected to the processing control unit 12 of the processing system 10 in a communicative manner, but the disclosure is not limited thereto.For example, the control system 50 may be connected to the laser oscillator 11 of the processing system 10, and the output of the laser oscillator 11 may be controlled based on the detected laser light signal and the welding light signal generated in the molten region.

[0037] As described above, the laser processing apparatus 100 of this embodiment can grasp the processing state of the workpiece 70 by detecting the welding light generated in the molten region on the processing surface. The configuration of the processing state monitoring device 20 of the laser processing apparatus 100 of this disclosure will be described in detail below.

[0038] (Configuration of the processing status monitoring device) In this embodiment, the processing state monitoring device 20 includes a light propagation correction element 30, a control device 35, a partial reflection mirror 23, a mirror 24, lenses 27 and 28, and photodetectors 42 and 43. This disclosure is not limited to the number of photodetectors included in the processing state monitoring device. For example, the processing state monitoring device 20 may include one photodetector to measure, for example, one of the thermal radiation light or plasma light contained in the welding light, or it may include two or more photodetectors to measure multiple different wavelengths of light contained in the welding light.

[0039] As shown in Figure 1, the detection light L20, which includes the first detection light L21 and the second detection light L22 generated from the molten region 71, enters the fθ lens 16, is reflected by the movable mirror 15, and then passes through the partial reflection mirror 14 before entering the processing state monitoring device 20.

[0040] In the processing state monitoring device 20, the propagation direction of the detected light L20 is corrected by the optical propagation correction element 30. The control device 35 is used to control the operation of the optical propagation correction element 30. The optical propagation correction element 30 and the control device 35 will be described in detail later.

[0041] The detection light L20 reaches the partial reflection mirror 23 after its propagation direction is corrected by the optical propagation correction element 30. In this embodiment, the partial reflection mirror 23 may be, for example, a dichroic mirror, which can transmit light in the wavelength range of the laser light and reflect light in other wavelength ranges. The partial reflection mirror 23 can be configured by selecting desired optical properties according to the application, and the ratio of transmitted light to reflected light may be changed as needed. In this embodiment, the detection light L20 includes a first detection light L21 and a second detection light L22. The first detection light L21 is reflected light from the laser light, and the second detection light L22 is light with a different wavelength from the laser light, for example, thermal radiation light in the infrared wavelength range or plasma light in the visible range. In this case, the first detection light L21, which is reflected light from the laser light, passes through the partial reflection mirror 23, is focused by the focusing lens 27, and is detected by the photodetector 42. Meanwhile, the second detection light L22, which has a different wavelength from the laser light, is reflected by the partial reflection mirror 23, then reflected again by the reflection mirror 24, and then focused by the focusing lens 28 and detected by the photodetector 43.

[0042] The photodetectors 42 and 43 may be positioned so that their light-receiving surfaces are located at the focal planes of the condensing lenses 27 and 28, or they may be positioned on the optical axes Oc and Od of the condensing lenses 27 and 28, in order to receive the first detection light L21 and the second detection light L22 to the maximum extent. The photodetectors 42 and 43 include, for example, a photodiode and an A / D converter, and detect the intensity of the first detection light L21 and the second detection light L22, and convert them into electrical signals S2 and S3 such as voltage or current values. Furthermore, the photodetectors 42 and 43 are communicably connected to the control system 50, and the signals S2 and S3 of the first detection light L21 and the second detection light L22 are transmitted to the control system 50 and used to determine the machining state on the machined surface 70a of the workpiece 70.

[0043] (Deviation in the direction of detection light propagation) Referring to Figure 2, the deviation in the propagation direction of the detected light L20 during propagation from the processing surface to the photodetector will be explained. Figure 2 is a conceptual diagram showing the deviation in the propagation direction of the detected light caused by the position of the molten region on the processing surface in a processing state monitoring device 20a that does not have a light propagation correction element.

[0044] In the laser processing apparatus 100a shown in Figure 2, the processing state monitoring device 20a does not have a light propagation correction element 30 and its control device 35, and a mirror 22 is placed in the position of the light propagation correction element 30 in Figure 1. The detection light L20 incident on the processing state monitoring device 20a is reflected by the mirror 22 and then reaches the partial reflection mirror 23.

[0045] Figure 2 shows the state in which the processing laser beam L11b is irradiated by the movable mirror 15 to a scanning position near the periphery of the processing surface 70a. At this time, the laser beam L11b moves away from the optical axis Ob of the fθ lens 16 and irradiates the processing point near the periphery of the processing surface 70a. A melting region 72 is formed around the irradiation spot of the light beam, and detection light L20 is generated from the melting region 72. Until the detection light L20 reaches the fθ lens 16, it travels in the same way as the first detection light L21 and the second detection light L22. However, after passing through the fθ lens 16, a deviation occurs in the direction of travel between the first detection light L21 and the second detection light L22, as shown in Figure 2.

[0046] The first detection light L21, which is the reflected light of the laser beam, passes through the fθ lens 16 and then passes through the center of the movable mirror 15, partial reflection mirror 14, mirror 22, and partial reflection mirror 23 as a substantially parallel light beam, is focused on the optical axis Oc of the focusing lens 27, and is detected by the photodetector 42.

[0047] On the other hand, the second detection light L22, which has a different wavelength from the laser light, passes through the fθ lens 16, then through the movable mirror 15, partial reflection mirror 14, mirror 22, partial reflection mirror 23, and mirror 24, and reaches the focusing lens 28 at an angle to the optical axis Od of the focusing lens 28. In this way, when the laser beam L11b is irradiated near the periphery of the processed surface 70a, a deviation in the propagation direction occurs when the second detection light L22, which has a different wavelength from the laser light, propagates from the processed surface to the photodetector.

[0048] The cause of this propagation direction deviation lies in the chromatic aberration of the fθ lens 16. The fθ lens 16 has the property that when light is transmitted through it, the refractive index differs depending on the wavelength of the light. Furthermore, the fθ lens 16 is adapted to the wavelength of the laser light in order to transmit the beam of the processing laser light L11b and focus it on the processing surface 70a. Therefore, as shown in Figure 2, the first detection light L21, which is the reflected light of the laser light, after passing through the fθ lens 16, is reflected by the movable mirror 15 while maintaining a substantially parallel light beam and can be incident on the optical axis of the partial reflection mirror 14 to the processing state monitoring device 20a. On the other hand, the second detection light L22, which has a different wavelength from the laser light, cannot maintain a parallel light beam after passing through the fθ lens 16 due to the chromatic aberration of the fθ lens 16, and is incident on the processing state monitoring device 20a at an angle to the optical axis of the partial reflection mirror 14, resulting in a propagation direction deviation.

[0049] Furthermore, the amount of deviation in the propagation direction of the second detection light L22 differs depending on the position where the laser beam L11b irradiates the processed surface 70a. For example, as shown in Figure 1, when the laser beam L11b irradiates the processed surface 70a along the optical axis Ob of the fθ lens 16, the detection light L20 generated from the molten region 71 in the central part of the processed surface 70a is transmitted through the fθ lens 16 in an approximately orthogonal direction, so there is almost no deviation in the propagation direction of the second detection light L22 due to chromatic aberration of the fθ lens 16. On the other hand, as shown in Figure 2, when the laser beam L11b irradiates the processed surface 70a away from the optical axis of the fθ lens 16, a large deviation in the propagation direction of the second detection light L22 occurs after the detection light L20 generated from the molten region 72 near the periphery of the processed surface 70a is transmitted through the fθ lens 16.

[0050] Thus, as the scanning angle of the movable mirror 15 increases, that is, as the molten region approaches the periphery of the processed surface 70a, the deviation in the propagation direction of the detection light, which has a different wavelength from the laser light, becomes larger. Since such detection light cannot be adequately detected by the photodetector of the processing state monitoring device, it is difficult to accurately detect the welding light from the processed surface 70a.

[0051] Therefore, the processing state monitoring device 20 according to the embodiment of this disclosure, as shown in Figure 1, includes an optical propagation correction element 30. The optical propagation correction element 30 receives detection light L20 from the molten region and corrects the propagation direction of the detection light L20 according to the position of the molten region on the processing surface 70a before emitting it to a photodetector. Furthermore, the detection light L20 propagated from the molten region may include light of two or more different wavelengths, and the optical propagation correction element 30 can correct the propagation direction of each of the two or more different wavelengths of light in the detection light L20 and emit them to the corresponding photodetectors.

[0052] In this embodiment, the optical propagation correction element 30 can be configured as a spatial light modulator (also referred to as SLM). The spatial light modulator (SLM) has a structure in which ellipsoidal liquid crystals are arranged in a two-dimensional tessellation on a substrate that receives incident light. When a control signal is input, the liquid crystal molecules tilt, changing the refractive index for the received light. The spatial light modulator (SLM) can adjust the wavefront of the emitted light by electrically controlling the phase distribution of the emitted light and spatially modulating it by independently controlling the voltage for each pixel and adjusting the arrangement of the liquid crystal molecules. The optical propagation correction element 30 configured as a spatial light modulator (SLM) is arranged to receive detection light L20, which includes detection light L21 and L22 of different wavelengths from the molten region 72, as shown in Figure 7 which will be described in detail later. At this time, the optical propagation correction element 30 can correct the phase distribution of the detection light L21 and L22 according to the position of the molten region on the processed surface and emit detection light L20 having an adjusted wavefront. The corrected detection light L21 and L22 are emitted so as to propagate to the corresponding photodetectors 42 and 43, respectively.

[0053] Furthermore, the light propagation correction element can be composed of one or more galvanometer mirrors. As shown in Figure 8, which will be described in detail later, the light propagation correction element 30A composed of galvanometer mirrors is arranged to include galvanometer mirrors 31 and 32 so as to separately receive detection light L22 and L23 of different wavelengths from the molten region 72. In this case, the light propagation correction element 30A can correct the reflection angle of each of the detection light L22 and L23 at the corresponding galvanometer mirrors 31 and 32 according to the position of the molten region on the processed surface. The corrected detection light L21, L22, and L23 of different wavelengths are emitted so as to propagate to the corresponding photodetectors 42, 43, and 44, respectively.

[0054] The operation of the optical propagation correction elements 30 and 30A, which are composed of spatial light modulators (SLMs) or galvanometer mirrors, will be described in more detail later.

[0055] Thus, the processing state monitoring device of this disclosure corrects the propagation direction of detected light according to the position of the molten region on the processing surface in the light propagation correction element and emits it to the photodetector, thereby improving the accuracy of detecting light from the processing surface. As a result, the processing state of the workpiece can be accurately grasped during laser processing.

[0056] In this embodiment, the processing state monitoring device 20 further includes a control device 35, which controls the operation of the optical propagation correction element 30. This disclosure is not limited to providing the control device within the processing state monitoring device; for example, the operation of the optical propagation correction element 30 can also be controlled by an external control device. The control of the control device 35 and the operation of the processing state monitoring device will be specifically described below with reference to Figures 3 to 7.

[0057] (Control device) The control device 35 controls the operation of the optical propagation correction element 30. For example, the control device 35 can receive data signals D related to processing parameters from the processing control unit 12, calculate the optical propagation correction amount based on the signals D, and control the operation of the optical propagation correction element 30. The configuration of the control device 35 will be described below with reference to Figure 3.

[0058] Figure 3 is a block diagram showing an example configuration of a control device 35 of a processing state monitoring device according to Embodiment 1 of the present disclosure. The control device 35 comprises a processor 351 and a storage device 352. The control device 35 realizes predetermined functions by having the processor 351 execute instructions stored in the storage device 352. The functions of the control device 35 may be configured with hardware alone, or they may be realized by a combination of hardware and software. Furthermore, the control device 35 may comprise one or more processors 351.

[0059] The processor 351 can be composed of, for example, a microcontroller, CPU, MPU, GPU, DSU, FPGA, ASIC, etc. The processor 351 may also consist of dedicated electronic circuits designed to perform a predetermined function.

[0060] The storage device 352 is a storage medium that stores programs and data for realizing the functions of the control device 35. The storage device 352 can be implemented, for example, by a hard disk (HDD), SSD, RAM, DRAM, ferroelectric memory, flash memory, magnetic disk, or a combination thereof.

[0061] For example, the control device 35 can store data signals D related to machining parameters received from the machining control unit 12 in the storage device 352, and further store various data calculated based on the data D in the storage device 352. The transmission and reception of signals by the control device 35 may be achieved by wired connection or by wireless transmission.

[0062] The storage device 352 stores the correction reference data 353 and the detected light propagation direction correction program 354. If the control device 35 is connected to a network, the correction reference data 353 and the detected light propagation direction correction program 354 may be downloaded from the network as needed. The operation of the light propagation correction element 30 can be controlled by the processor 351 using the detected light propagation direction correction program 354. The correction reference data 353 will be described in detail later.

[0063] The detected light propagation direction correction program 354 controls the operation of the light propagation correction element 30. It reads from the storage device 352 and uses the correction reference data 353 read from the storage device 352 to cause the processor 351 to execute the detected light propagation direction correction process. The operation of the detected light propagation direction correction process 350 and the light propagation correction element 30 will be described below with reference to Figure 4-7.

[0064] Figure 4 is a flowchart of the detection light propagation direction correction process 350 of the processing state monitoring device according to Embodiment 1 of the present disclosure. Figure 5 is a diagram conceptually showing the calculation of the position of the melting region. Figure 6 is a diagram conceptually showing the acquisition of the propagation direction correction amount by referring to the correction reference data. Figure 7 is a schematic plan view showing the operation of the processing state monitoring device 20, which is an example configuration of a laser processing apparatus 100 equipped with the processing state monitoring device 20 according to Embodiment 1 of the present disclosure. Figure 8 is a schematic plan view showing the operation of the processing state monitoring device 20A, which is an example configuration of a laser processing apparatus 100A equipped with the processing state monitoring device 20A according to Embodiment 1 of the present disclosure.

[0065] (An example configuration of a laser processing apparatus equipped with a processing status monitoring device) In the laser processing apparatus 100 shown in Figure 7, when laser processing is started, the laser oscillator 11 receives a command from the processing control unit 12 and outputs laser light L11 at a set power. The processing control unit 12 operates a processing stage (not shown) that supports the movable mirror 15 and / or the workpiece 70 and scans the beam of processing laser light L11b over the processing surface 70a of the workpiece 70. At a predetermined scanning position, the laser light beam irradiates the processing surface 70a with an irradiation spot having a shape and size defined by the applied beam pattern. As shown in Figure 7, in this embodiment, the laser light L11b beam irradiates near the periphery of the processing surface 70a of the workpiece 70, forming a molten region 72 around the irradiation spot, and welding light is generated from the molten region 72.

[0066] From the welding light generated from the molten region 72 near the periphery of the processed surface 70a, detection light L20 is propagated from the processed surface 70a to the processing state monitoring device 20 for detection. In this embodiment, detection light L20 includes a first detection light L21 and a second detection light L22. The first detection light L21 is reflected light from a laser beam, and the second detection light L22 is light with a wavelength different from that of the laser beam, and may be, for example, thermal radiation light in the infrared wavelength range or plasma light in the visible range.

[0067] The detection light L20 passes through the fθ lens 16, through the movable mirror 15 and the partial reflection mirror 14, enters the processing state monitoring device 20, and reaches the light propagation correction element 30. As described above, due to the chromatic aberration of the fθ lens 16, a deviation in the propagation direction of the second detection light L22 occurs, and the two detection lights L21 and L22 reach the light propagation correction element 30 at an angle.

[0068] The optical propagation correction element 30 of the processing state monitoring device 20 in Figure 7 is composed of a spatial light modulator (SLM) and is positioned to receive the first detection light L21 and the second detection light L22 from the molten region 72. The control device 35 that controls the optical propagation correction element 30 executes the detection light propagation direction correction process 350 shown in Figure 4 to correct the phase distribution of the incident detection light L20.

[0069] (Detection light propagation direction correction process) In step S101, processing parameters that define the laser beam irradiation spot forming the molten region are acquired. At this time, the control device 35 can receive data signals D related to the processing parameters from the processing control unit 12.

[0070] Figure 5 shows an example of a schematic diagram of processing by irradiating the workable area 70A of the workable surface 70a with multiple laser beams L11b. In the illustrated example, the workable area 70A includes nine irradiation areas A11-A33, and the laser beam L11b scans each irradiation area to perform processing. At the scanning position within each irradiation area, the laser beam L11b irradiates the workable surface with a roughly circular irradiation spot 72A of a predetermined size according to the applied beam pattern, and a melted area 72 is formed around the irradiation spot 72A.

[0071] At this time, the processing control unit 12 acquires processing parameters that define the irradiation spot 72A of the laser beam L11b that forms the melting region 72. The acquired processing parameters include the position of the irradiation region A11 that defines the scanning position of the irradiation spot 72A on the processing surface 70a, and the beam pattern of the laser beam L11b that defines the shape and size of the irradiation spot 72A.

[0072] This disclosure is not limited to the number of irradiation areas included in the machinable area 70A. The machinable area 70A can include any number of irradiation areas. Furthermore, the processing parameters described above are merely examples, and this disclosure is not limited thereto. The processing parameters can be configured according to the actual laser processing.

[0073] Next, in step S102, the position of the melting region is calculated. At this time, the control device 35 uses the processing parameters acquired in step S101 to calculate the position 82 of the melting region 72 formed by the irradiation spot 72A. Specifically, the position coordinates (x,y) of the position 82 of the melting region 72 are calculated based on the scanning position of the irradiation spot 72A defined by the position of the irradiation region A11 and the shape and size of the irradiation spot 72A defined by the beam pattern of the laser light L11b. In this embodiment, the position coordinates (x,y) of the position 82 of the melting region 72 can be calculated as the geometric center of the generally circular irradiation spot 72A.

[0074] This disclosure is not limited to the shape or size of the irradiation spot. The irradiation spot may be defined by any beam pattern of the laser light. The control device 35 may, for example, use a predetermined algorithm to calculate the position of the melting region formed by the irradiation spot of the laser light beam to which a predetermined beam pattern is applied at a predetermined scanning position.

[0075] Next, in step S103, the optical propagation correction element 30 obtains a propagation direction correction amount for the detected light L20 that has been propagated. At this time, the control device 35 can obtain a propagation direction correction amount corresponding to the position 82 of the melted region calculated in step S102 by referring to the correction reference data 353 stored in the storage device 352.

[0076] In this specification, the correction reference data 353 stored in the storage device 352 of the control device 35 includes data showing the correlation between a reference position on the processed surface and the amount of propagation direction correction applied to the light propagation correction element 30 by the detected light L20 propagated from the reference position to the light propagation correction element 30.

[0077] In the laser processing apparatus 100 shown in Figure 7, the optical propagation correction element 30 of the processing state monitoring device 20 is composed of a spatial light modulator (SLM). In this case, the correction reference data 353 includes data showing the correlation between a reference position on the processing surface and the amount of phase distribution correction corrected by the optical propagation correction element 30 so that the detected light L21 and L22 propagated from the reference position to the optical propagation correction element 30 propagates to the corresponding photodetectors 42 and 43.

[0078] Specifically, when the optical propagation correction element 30 is composed of a spatial light modulator (SLM), the correction reference data 353 may be, for example, the correction table 90 shown in Figure 6. The grid points of the correction table 90 are used as reference positions on the processing surface, and the phase distribution correction amount that the detected light propagated from each reference position to the optical propagation correction element 30 is corrected by the optical propagation correction element 30 is calculated in advance by simulation, for example, and recorded in the correction table 90. The correction table 90 may, for example, divide the machinable area 70A on the processing surface shown in Figure 5 into 32 × 32 and define each grid point as a reference position, but this disclosure is not limited to the number of reference positions included in the correction table 90. For example, the machinable area 70A on the processing surface can be further divided, and high-precision correction can be performed on the detected light based on the phase distribution correction amount corresponding to a large number of reference positions.

[0079] In step S103, when calculating the propagation direction correction amount for the detected light L20, as shown in Figure 6, a reference position 92 is calculated, which is a grid point of the correction table 90 having the position coordinates (x1,y1) closest to the position coordinates (x,y) of the melted region position 82 calculated in step S102. Then, the phase distribution correction amount corresponding to the reference position 92 recorded in the correction table 90 can be obtained as the propagation direction correction amount for the detected light L20 propagated by the optical propagation correction element 30.

[0080] Next, in step S104, the control device 35 transmits a control signal E to the optical propagation correction element 30, and operates the optical propagation correction element 30 to correct the detected light L20 using the propagation direction correction amount obtained in step S103. The optical propagation correction element 30 of the processing state monitoring device 20 corrects the phase distribution of the detected light L20, thereby correcting the deviation in the propagation direction that occurred in the second detected light L22, which has a different wavelength from the laser light, due to the chromatic aberration of the fθ lens 16. As shown in Figure 7, the corrected detected light L20 has its wavefront adjusted and is emitted from the optical propagation correction element 30 as an approximately parallel light beam and propagates to the photodetectors 42 and 43.

[0081] Figure 7 shows an example in which a processing state monitoring device 20 detects detection light L20, which includes a first detection light L21 that is reflected light from a laser beam and a second detection light L22 that has a different wavelength from the laser beam, but the disclosure is not limited thereto. The detection light propagated to and detected by the processing state monitoring device 20 may include, for example, light with a different wavelength from one of the laser beams, or light with two or more different wavelengths. For example, in the configuration example of the laser processing apparatus 100 shown in Figure 7, both the first detection light L21 and the second detection light L22 may have different wavelengths from the laser beam, and the first detection light L21 and the second detection light L22, which have different wavelengths from the laser beam, can be propagated to the photodetectors 42 and 43, respectively, by similarly correcting the phase distribution of the light propagation correction element 30.

[0082] The optical propagation correction element 30, composed of a spatial light modulator (SLM), corrects the phase distribution of the detected light and adjusts the wavefront of the emitted light to correct the propagation direction of the detected light. As a result, deviations in the propagation direction that occur in light of different wavelengths from the multiple laser light wavelengths contained in the detected light are corrected simultaneously. Therefore, a processing state monitoring device equipped with an optical propagation correction element 30 composed of a spatial light modulator (SLM) has an optical system composed of a small number of optical components, and the propagation directions of multiple different wavelengths of detected light can be corrected simultaneously with simple optical axis adjustment.

[0083] After being emitted from the light propagation correction element 30, the first detection light L21, which is reflected light of the laser beam, passes through the partial reflection mirror 23, is focused on the optical axis Oc of the focusing lens 27, and is detected by the photodetector 42. The second detection light L22, which is light with a different wavelength from the laser beam, is reflected by the partial reflection mirror 23 and the reflection mirror 24, is focused on the optical axis Od of the focusing lens 28, and is detected by the photodetector 43.

[0084] After step S104 is performed, the process proceeds to step S105. In step S105, it is determined whether or not the laser processing is complete, and the detected light propagation direction correction process 350 is repeatedly executed from step S101 to step S105 until the laser processing is complete.

[0085] In this way, the processing state monitoring device 20 corrects the propagation direction of the detected light propagated according to the position of the molten region on the processing surface in the light propagation correction element 30, thereby emitting and detecting detected light of each wavelength so that it propagates to the corresponding photodetector. In this manner, the processing state monitoring device 20 can improve the accuracy of detecting light from the processing surface, and based on the detection results of the processing state monitoring device 20, it can accurately grasp the processing state of the workpiece during laser processing.

[0086] (Other configuration examples of laser processing equipment equipped with a processing status monitoring device) The laser processing apparatus 100A shown in Figure 8 differs from the laser processing apparatus 100 shown in Figure 7 in the configuration of the processing status monitoring device 20A. The laser processing apparatus 100A will be described below, focusing on these differences. Note that in Figure 8, components that are substantially identical to those in the laser processing apparatus 100 of Figure 7 are given the same reference numerals.

[0087] In the configuration example shown in Figure 8, detection light L20A is propagated from the welding light generated from the molten region 72 near the periphery of the processed surface 70a to the processing state monitoring device 20A for detection. In this embodiment, detection light L20A includes a first detection light L21, a second detection light L22, and a third detection light L23. The first detection light L21 is reflected light from the laser beam, and the second detection light L22 and the third detection light L23 have different wavelengths from each other and are light with wavelengths different from the laser beam. For example, the second detection light L22 and the third detection light L23 may be thermal radiation light in the infrared wavelength range and plasma light in the visible range, respectively.

[0088] The detection light L20A passes through the fθ lens 16, through the movable mirror 15 and the partial reflection mirror 14, enters the processing state monitoring device 20A, and reaches the partial reflection mirror 22. As mentioned above, due to the chromatic aberration of the fθ lens 16, a deviation in the propagation direction occurs between the second detection light L22 and the third detection light L23, so the three detection lights L21, L22, and L23 reach the partial reflection mirror 22 at an angle.

[0089] The optical propagation correction element 30A of the processing state monitoring device 20A in Figure 8 is composed of galvanometer mirrors 31 and 32. The third detection light L23 from the molten region 72 passes through the partial reflection mirror 22 and reaches the galvanometer mirror 31. The first detection light L21 and the second detection light L22 are reflected by the partial reflection mirror 22 and then reach the partial reflection mirror 23. The second detection light L22 is reflected by the partial reflection mirror 23 and reaches the galvanometer mirror 32. In this way, in the optical propagation correction element 30A, the galvanometer mirrors 31 and 32 are arranged to receive the second detection light L22 and the third detection light L23, which have different wavelengths from the laser light, separately. The first detection light L21 passes through the partial reflection mirror 23, is focused by the focusing lens 27, and is detected by the photodetector 42.

[0090] Furthermore, the number of galvanometer mirrors constituting the optical propagation correction element can be provided in proportion to the number of detected light wavelengths different from the wavelength of the detected laser light, and this disclosure is not limited to the number of galvanometer mirrors constituting the optical propagation correction element.

[0091] The optical propagation correction element 30A, composed of galvanometer mirrors 31 and 32, is controlled by a control device 35A. The control device 35A may have a configuration similar to that of the control device 35 shown in Figure 3, and the operation of the optical propagation correction element 30A can be controlled by executing the detected optical propagation direction correction process 350 shown in Figure 4.

[0092] In executing the detection light propagation direction correction process 350, in steps S101 to S102, the control device 35A processes in the same way as the control device 35 of the processing state monitoring device 20. In step S103, when the control device 35A obtains the propagation direction correction amount for the detection light L20A, the correction reference data 353 that is referenced has a different configuration from that of the control device 35.

[0093] In the laser processing apparatus 100A shown in Figure 8, the optical propagation correction element 30A of the processing state monitoring device 20A is composed of galvanometer mirrors 31 and 32. In this case, the correction reference data 353 includes data showing the correlation between a reference position on the processing surface and the amount of reflection angle correction corrected by the galvanometer mirrors 31 and 32 so that the detected light L22 and L23 propagated from the reference position to the galvanometer mirrors 31 and 32 propagates to the corresponding photodetectors 43 and 44.

[0094] Specifically, when the optical propagation correction element 30A is composed of galvanometer mirrors 31 and 32, the correction reference data 353 stored in the memory of the control device 35A may be, for example, the correction table 90 shown in Figure 6. The grid points of the correction table 90 are used as reference positions on the processed surface, and the amount of reflection angle correction corrected by each galvanometer mirror so that the detected light propagated from each reference position to each galvanometer mirror propagates to the corresponding photodetector is calculated in advance by simulation, for example, and recorded in the correction table 90. At this time, each reflection angle correction amount is calculated in accordance with the wavelength of the detected light propagated to each galvanometer mirror and is used to correct the propagation direction in the corresponding galvanometer mirror.

[0095] In step S103, the propagation direction correction amount for the detected light L20A is calculated, for example, as shown in Figure 6, to be a reference position 92 which is a grid point of the correction table 90 having a position coordinate (x1,y1) closest to the position coordinate (x,y) of the melted region position 82 calculated in step S102. In the optical propagation correction element 30A of the processing state monitoring device 20A shown in Figure 8, galvanometer mirrors 31 and 32 are provided corresponding to the second detected light L22 and the third detected light L23, which have different wavelengths. The galvanometer mirrors 31 and 32 are calculated for the reference position 92 recorded in the correction table 90, and the propagation direction of the second detected light L22 and the third detected light L23 is corrected using the reflection angle correction amount corresponding to the detected light L22 and L23, respectively.

[0096] The correction reference data 353 stored in the storage device of the control device 35A is not limited to the format of the correction table 90. For example, the correction reference data 353 may be in graph form, representing the values ​​of the reflection angle correction amount corrected by the corresponding galvanometer mirror according to each reference position on the machined surface. This graph may be calculated in advance by simulation, for example, and stored in the storage device of the control device 35A as the correction reference data 353.

[0097] In step S104 of the detection light propagation direction correction process 350 shown in Figure 4, the control device 35A transmits control signals E1 and E2 to the galvanometer mirrors 31 and 32, respectively, which constitute the light propagation correction element 30A, and operates the galvanometer mirrors 31 and 32 to correct the detection light L22 and L23 using the propagation direction correction amount obtained in step S103. At this time, the control device 35A operates the galvanometer mirrors 31 and 32 using the calculated respective reflection angle correction amounts to correct the deviation in propagation direction that occurred between the second detection light L22 and the third detection light L23.

[0098] Returning to Figure 8, the third detection light L23 emitted from the galvanometer mirror 31 has its propagation direction deviation corrected and is substantially focused on the optical axis Oe of the focusing lens 29, where it is detected by the photodetector 44. Similarly, the second detection light L22 emitted from the galvanometer mirror 32 also has its propagation direction deviation corrected and is substantially focused on the optical axis Od of the focusing lens 28, where it is detected by the photodetector 43.

[0099] From S104 onward, the control device 35A processes in the same manner as the control device 35 of the processing state monitoring device 20.

[0100] In this way, the processing state monitoring device 20A corrects the propagation direction of the detected light propagated according to the position of the molten region on the processing surface in the light propagation correction element 30A, thereby emitting and detecting detected light of each wavelength so that it propagates to the corresponding photodetector. In this manner, the processing state monitoring device 20A can improve the accuracy of detecting light from the processing surface, and based on the detection results of the processing state monitoring device 20A, it is possible to accurately grasp the processing state of the workpiece during laser processing.

[0101] (Other embodiments) (Note) Based on the above description of embodiments, the following technologies are disclosed. (Technology 1) A device for monitoring the processing state in laser processing, which is performed by irradiating the processing surface of a workpiece with laser light, comprising: at least one photodetector that detects first light propagating from a molten region formed around the irradiation spot of the laser light on the processing surface and containing light of a different wavelength from the wavelength of the laser light; and an optical propagation correction element disposed between the processing surface and at least one photodetector, wherein the optical propagation correction element receives the first light from the molten region and corrects the propagation direction of the first light according to the position of the molten region on the processing surface before emitting it to at least one photodetector.

[0102] This configuration improves the accuracy of detecting light from the processing surface during laser processing.

[0103] (Technology 2) The processing state monitoring apparatus according to Technology 1, wherein the first light comprises light of two or more different wavelengths, at least one photodetector separately detects light of two or more different wavelengths, and an optical propagation correction element corrects the propagation direction of light of two or more different wavelengths in the first light.

[0104] This configuration improves the accuracy of detecting two or more different wavelengths of light from the processing surface during laser processing.

[0105] (Technology 3) The machining state monitoring device according to Technology 2, further comprising a control device for controlling an optical propagation correction element, the control device comprising a processor and a memory device storing instructions executed by the processor and correction reference data, wherein the correction reference data includes data showing a correlation between a reference position on the machining surface and a propagation direction correction amount corrected by the optical propagation correction element for first light propagated from the reference position to the optical propagation correction element, and the instruction includes operating the optical propagation correction element to correct the propagation direction of the first light by a propagation direction correction amount calculated based on the position of the molten region and the correction reference data.

[0106] This configuration allows for control during laser processing to improve the accuracy of detecting light from the processing surface.

[0107] (Technical 4) The processing state monitoring device according to Technical 3, wherein operating an optical propagation correction element to correct the propagation direction of the first light with a propagation direction correction amount calculated based on the position of the molten region and correction reference data includes: acquiring processing parameters that define the irradiation spot of the laser light forming the molten region; calculating the position of the molten region on the processing surface based on the acquired processing parameters; obtaining a propagation direction correction amount corresponding to the calculated position of the molten region by referring to correction reference data; and operating an optical propagation correction element to correct the propagation direction of the first light using the obtained propagation direction correction amount.

[0108] This configuration allows for control during laser processing to improve the accuracy of detecting light from the processing surface.

[0109] (Technical 5) The processing state monitoring device according to Technical 3, wherein the optical propagation correction element is a spatial light modulator arranged to receive first light of each wavelength from the molten region, and the correction reference data includes data showing the correlation between a reference position on the processing surface and the amount of phase distribution correction that is corrected by the optical propagation correction element for the first light propagated from the reference position to the optical propagation correction element.

[0110] This configuration allows for improved detection accuracy of light from the processing surface during laser processing using a spatial light modulator.

[0111] (Technical 6) The processing state monitoring device according to Technical 3, wherein the optical propagation correction element is one or more galvano mirrors arranged to separately receive first light of each wavelength from the molten region, and the correction reference data includes data showing the correlation between a reference position on the processing surface and the amount of reflection angle correction that the first light propagated from the reference position to one or more galvano mirrors is corrected by one or more galvano mirrors.

[0112] This configuration allows for improved accuracy in detecting light from the processing surface during laser processing by using one or more galvanometer mirrors.

[0113] (Technical 7) The processing state monitoring apparatus according to any one of Technical 1 to Technical 6, wherein the first light includes at least one of light in the infrared wavelength range and light in the visible range emitted from the molten region during laser irradiation.

[0114] This configuration allows for improved control during laser processing to enhance the detection accuracy of light, including infrared and / or visible light, emanating from the processing surface.

[0115] (Technical 8) A laser processing apparatus comprising a processing system that emits laser light and irradiates the processing surface of a workpiece to perform laser processing, and a processing state monitoring device described in any one of Technical 1 to Technical 7.

[0116] This configuration allows for laser processing that improves the accuracy of light detection from the processing surface.

[0117] (Technical 9) A method for monitoring the processing state in laser processing, which is performed by irradiating the processing surface of a workpiece with laser light, comprising: guiding a first light, which is propagated from a molten region formed around the irradiation spot of the laser light and includes light of a different wavelength from the wavelength of the laser light, to an optical propagation correction element; correcting the propagation direction of the first light in the optical propagation correction element according to the position of the molten region on the processing surface and emitting it to at least one photodetector; and detecting the first light emitted from the optical propagation correction element in at least one photodetector.

[0118] This method improves the accuracy of detecting light from the processing surface during laser processing.

[0119] (Technical 10) The processing state monitoring method according to Technical 9, wherein guiding a first light to an optical propagation correction element comprises guiding a first light containing two or more different wavelengths of light to an optical propagation correction element, correcting the propagation direction of the first light and emitting it to at least one photodetector comprises correcting the propagation direction of two or more different wavelengths of light in the first light, and detecting the first light emitted from the optical propagation correction element comprises separately detecting two or more different wavelengths of light.

[0120] This method improves the accuracy of detecting two or more different wavelengths of light from the processing surface during laser processing.

[0121] (Technical 11) A method for monitoring the processing state according to Technical 9 or 10, wherein, in an optical propagation correction element, correcting the propagation direction of first light according to the position of a molten region on a processing surface and emitting it to at least one photodetector includes: acquiring processing parameters that define the irradiation spot of the laser light forming the molten region; calculating the position of the molten region on the processing surface based on the acquired processing parameters; obtaining a propagation direction correction amount corresponding to the calculated position of the molten region by referring to correction reference data; and operating the optical propagation correction element to correct the propagation direction of first light using the obtained propagation direction correction amount, wherein the correction reference data includes data showing the correlation between a reference position on the processing surface and the propagation direction correction amount corrected by the optical propagation correction element for first light propagated from the reference position to the optical propagation correction element.

[0122] This method allows for control during laser processing to improve the accuracy of detecting light from the processing surface.

[0123] Furthermore, by appropriately combining any of the above various embodiments, the effects of each can be achieved.

[0124] As described above, the attached drawings and detailed description are provided to illustrate the embodiments of the technology described herein. Therefore, the components described in the attached drawings and detailed description may include not only components essential for solving the problem, but also components that are not essential for solving the problem, in order to illustrate the technology described above. Therefore, the mere presence of such non-essential components in the attached drawings and detailed description should not be immediately assumed to mean that those non-essential components are essential.

[0125] While this disclosure is fully described in relation to preferred embodiments with reference to the accompanying drawings, various modifications are possible within the scope of the claims. Such modifications, as well as embodiments obtained by appropriately combining the technical means disclosed in different embodiments, are also included in the technical scope of this disclosure. [Industrial applicability]

[0126] This disclosure is applicable to devices for monitoring the processing state in laser processing. This disclosure is applicable to laser processing for monitoring the processing state. [Explanation of Symbols]

[0127] 10 Processing Systems 11. Laser Oscillator 12 Machining Control Unit 13. Collimating lenses 14. Partially reflective mirror 15. Movable Mirror 16 fθ lens 20,20A Processing Status Monitoring Device 22,23 Partially reflective mirror 24 Mirror 27, 28, 29 lenses 30,30A Optical propagation correction element 31,32 Galvano Mirror 35,35A Control device 41, 42, 43, 44 Photodetectors 50 Control Systems 70 Work 70a Machined surface 70A machinable area 71,72 Melting region 72A Irradiation Spot 82 Location of the molten region 90 Correction Table 92 Reference position 100, 100A Laser Processing Machine 353 Correction Reference Data L11, L11a, L11b laser light L20, L21, L22, L23 detection light

Claims

1. In laser processing, which involves irradiating the processing surface of a workpiece with laser light, a device for monitoring the processing state is provided. A photodetector that detects first light, which is propagated from a molten region formed around the laser beam irradiation spot on the processed surface and includes light of a different wavelength from the laser beam, A light propagation correction element is disposed between the processed surface and at least one of the photodetectors, Equipped with, The light propagation correction element receives the first light from the molten region and corrects the propagation direction of the first light according to the position of the molten region on the processed surface before emitting it to at least one of the photodetectors. Processing status monitoring device.

2. The first light comprises light of two or more different wavelengths, At least one of the photodetectors separately detects the two or more different wavelengths of light, The optical propagation correction element corrects the propagation direction of the two or more different wavelengths of light in the first light. The processing state monitoring device according to claim 1.

3. The system further includes a control device for controlling the aforementioned optical propagation correction element, The control device is Processor and A storage device that stores instructions executed by the processor and correction reference data, Equipped with, The correction reference data includes data showing the correlation between the reference position on the processed surface and the amount of propagation direction correction applied to the first light propagated from the reference position to the light propagation correction element, which is corrected by the light propagation correction element. The instruction includes activating the optical propagation correction element to correct the propagation direction of the first light by a propagation direction correction amount calculated based on the location of the melted region and the correction reference data. The processing state monitoring device according to claim 2.

4. Operating the optical propagation correction element to correct the propagation direction of the first light by a propagation direction correction amount calculated based on the position of the melted region and the correction reference data is: To obtain processing parameters that define the irradiation spot of the laser beam that forms the molten region, Based on the acquired processing parameters, the position of the molten region on the processed surface is calculated, By referring to the aforementioned correction reference data, a propagation direction correction amount corresponding to the calculated position of the melted region is obtained, The optical propagation correction element is operated to correct the propagation direction of the first light using the obtained propagation direction correction amount, including, The processing state monitoring device according to claim 3.

5. The light propagation correction element is a spatial light modulator arranged to receive the first light of each wavelength from the melted region, The correction reference data includes data showing the correlation between a reference position on the processed surface and the amount of phase distribution correction applied to the first light propagated from the reference position to the optical propagation correction element. The processing state monitoring device according to claim 3.

6. The light propagation correction element comprises one or more galvanometer mirrors arranged to separately receive the first light of each wavelength from the molten region, The correction reference data includes data showing the correlation between a reference position on the processed surface and the amount of reflection angle correction applied to the first light propagated from the reference position to one or more of the galvanometer mirrors, which is corrected by one or more of the galvanometer mirrors. The processing state monitoring device according to claim 3.

7. The first light includes at least one of light in the infrared wavelength range and light in the visible range emitted from the melting region during irradiation with the laser light. A processing state monitoring device according to any one of claims 1 to 6.

8. A processing system that emits laser light and irradiates the processing surface of a workpiece to perform laser processing, The processing state monitoring device according to any one of claims 1 to 6, Equipped with, Laser processing equipment.

9. A method for monitoring the processing state in laser processing, which is performed by irradiating the processing surface of a workpiece with laser light, To guide the first light, which propagates from the molten region formed around the laser beam irradiation spot and includes light of a different wavelength from the laser beam, to the optical propagation correction element. In the light propagation correction element, the propagation direction of the first light is corrected according to the position of the molten region on the processed surface and emitted to at least one photodetector. In at least one of the photodetectors, the first light emitted from the light propagation correction element is detected, including, A method for monitoring the processing status.

10. Guiding the first light to the optical propagation correction element includes guiding the first light, which includes light of two or more different wavelengths, to the optical propagation correction element. Correcting the propagation direction of the first light and emitting it to at least one photodetector includes correcting the propagation directions of two or more different wavelengths of light in the first light, Detecting the first light emitted from the light propagation correction element involves separately detecting two or more different wavelengths of light. The method for monitoring the processing state according to claim 9.

11. In the light propagation correction element, the propagation direction of the first light is corrected according to the position of the molten region on the processed surface and emitted to at least one photodetector, To obtain processing parameters that define the irradiation spot of the laser beam that forms the molten region, Based on the acquired processing parameters, the position of the molten region on the processed surface is calculated, By referring to the correction reference data, a propagation direction correction amount corresponding to the calculated position of the melted region is obtained, The optical propagation correction element is operated to correct the propagation direction of the first light using the obtained propagation direction correction amount, Includes, The correction reference data includes data showing the correlation between a reference position on the processed surface and the amount of propagation direction correction applied to the first light propagated from the reference position to the light propagation correction element. The method for monitoring the processing state according to claim 9 or 10.

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