Laser processing head, laser processing system, and abnormality determination method thereof

Abstract

The present disclosure provides a laser processing head, a laser processing system, and an abnormality determination method thereof. A laser processing head (10) has a housing (11) and a plurality of optical components. In the housing (11), a partition wall (11a), first and second light incident ports (12a, 12b) that respectively incident first and second lasers (A, B), and a light irradiation port (13) are provided. The laser processing head (10) includes first and second light detectors (91b, 92a) that are respectively provided around the first and second light incident ports (12a, 12b). The first light detector (91b) is disposed on the side opposite to the second light detector (92a) with the partition wall (11a) interposed. The first light detector (91b) receives light of a second wavelength band including the wavelength of the second laser (B), and the second light detector (92a) receives light of a first wavelength band including the wavelength of the first laser (A).

Description

Technical Field

[0001] This disclosure relates to a laser processing head, and more particularly, to a laser processing head that emits two laser beams of different wavelengths, a laser processing system having the same, and a method for judging anomalies in the laser processing system. Background Technology

[0002] Laser processing systems perform laser processing tasks such as cutting, welding, and drilling on workpieces. In a laser processing system, the laser processing head emits a laser beam from a laser oscillator and guides it through an optical fiber, irradiating the workpiece. The laser processing head is equipped with a focusing optical system for concentrating the laser beam and directing it onto the workpiece.

[0003] During laser processing, molten workpiece material or other sputtering particles may adhere to the optical components located on the laser processing head. If such sputtering occurs, the laser beam will be scattered inside the laser processing head, preventing it from irradiating the workpiece with the desired power, potentially leading to substandard processing and reduced processing quality.

[0004] To address this issue, for example, Patent Document 1 discloses a laser processing system in which an inspection laser with a lower output than the processing laser is generated by a laser oscillator, and the inspection laser is used to irradiate the workpiece via a laser processing head. Inside the laser processing head, a light-receiving section is provided to receive the reflected light from the workpiece. Based on the intensity of the reflected light detected by the light-receiving section, the contamination level of the protective glass covering the light irradiation port of the laser processing head is determined, and the degree of power reduction of the processing laser irradiating the workpiece is also determined. If the power reduction is small, the output of the processing laser is adjusted and laser processing is performed; if the reduction is large, laser processing is interrupted.

[0005] Prior art literature

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2016-097412

[0008] However, in recent years, hybrid laser processing systems, such as those using near-infrared and blue lasers with different wavelengths, have become known. These systems combine two lasers with different wavelengths along the same optical axis using a laser processing head, focusing each laser beam separately onto the workpiece. Hybrid laser processing systems can utilize the strengths of each laser while compensating for its weaknesses, thus offering more advantages compared to existing laser processing systems that use only one type of laser.

[0009] In this hybrid laser processing system, similar to Patent Document 1, it is necessary to determine the internal state of the laser processing head. Furthermore, it is also necessary to detect the reflected light from the workpiece, and determine the processing state of the workpiece based on the results.

[0010] However, in the existing structure disclosed in Patent Document 1, it is difficult to distinguish between the reflected light from the workpiece and the vignetting light at the optical components inside the laser processing head to determine the processing state of the workpiece and the internal state of the laser processing head. In particular, in hybrid laser processing systems, where multiple optical components are arranged in the optical paths of each laser, these state determinations become even more difficult. Summary of the Invention

[0011] This disclosure is made in view of this situation, and its object is to provide a laser processing head and a laser processing system having the same, which are capable of determining the processing status of a workpiece based on reflected light in a laser processing head that irradiates a workpiece with lasers of different wavelengths.

[0012] The laser processing head disclosed herein is a laser processing head having a housing and a plurality of optical components disposed inside the housing. The housing is characterized by the following: a first light entrance for receiving a first laser beam; a second light entrance for receiving a second laser beam; a light irradiation port for emitting both the first and second laser beams to the outside; and a partition separating the optical path of the first laser beam received from the first light entrance from the optical path of the second laser beam received from the second light entrance, wherein the wavelength of the second laser beam is shorter than the wavelength of the first laser beam. The laser processing head further comprises: a first photodetector disposed in the optical path of the first laser beam received from the first light entrance. The first photodetector is disposed around the second laser beam incident from the second light inlet, and the second photodetector is disposed on the side opposite to the second photodetector, which is sandwiched between the partition wall. The first photodetector receives light in a second band containing the wavelength of the second laser, and the second photodetector receives light in a first band containing the wavelength of the first laser. At least a portion of the plurality of optical components are disposed inside the housing to alter the optical path of at least one of the first laser and the second laser, so that the optical axis of the first laser emitted from the light inlet is substantially aligned with the optical axis of the second laser.

[0013] The laser processing system disclosed herein is characterized by comprising at least: the laser processing head; a first laser oscillator emitting the first laser; a second laser oscillator emitting the second laser; a first optical fiber connected to the first optical input port for transmitting the first laser emitted from the first laser oscillator to the laser processing head; and a second optical fiber connected to the second optical input port for transmitting the second laser emitted from the second laser oscillator to the laser processing head, wherein the laser processing head irradiates a workpiece with at least one of the first laser and the second laser.

[0014] The anomaly detection method of the laser processing system disclosed herein is an anomaly detection method for determining the presence or absence of anomalies in the laser processing system. Its characteristics are: when the second laser irradiates the workpiece, based on the output signal of the first photodetector, it determines whether there is an anomaly in the processing state of the workpiece or the state of the optical components inside the housing; and when the first laser irradiates the workpiece, based on the output signal of the second photodetector, it determines whether there is an anomaly in the processing state of the workpiece or the state of the optical components inside the housing.

[0015] According to this disclosure, in a hybrid laser processing system, the processing status of a workpiece can be determined. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the laser processing system involved in Implementation Method 1.

[0017] Figure 2 This is a schematic diagram showing the internal structure of a laser processing head.

[0018] Figure 3 This is a schematic diagram showing the pixel structure of an image sensor.

[0019] Figure 4 This is a graph illustrating an example of the relationship between the light-receiving efficiency of an RGB pixel and its wavelength.

[0020] Figure 5A This is an example of an image showing the light spots of the first and second lasers focused onto the light-receiving surface of an image sensor.

[0021] Figure 5B This is an example of an image showing the light spots of the first and second lasers focused on the surface of a workpiece.

[0022] Figure 6A This is a schematic diagram of the first and third photodetectors.

[0023] Figure 6BThis is a schematic diagram of the second and fourth photodetectors.

[0024] Figure 7 This is a schematic diagram showing the state of reflected light when the first laser beam is directed at the workpiece.

[0025] Figure 8 This is a schematic diagram showing the state of reflected light when the second laser is irradiated onto the workpiece.

[0026] Figure 9 This is an example of the output of the first to fourth photodetectors when the first and second lasers are irradiated onto the workpiece.

[0027] Figure 10 This is an example of the outputs of the second and third photodetectors in the case where the first laser is irradiated onto the workpiece according to Embodiment 2.

[0028] Figure 11 This is a schematic diagram of the laser processing system involved in Implementation Method 3.

[0029] Figure 12 This is an example of the outputs of the second, third, and sixth photodetectors when the first laser is used to irradiate the workpiece.

[0030] -Symbol Explanation-

[0031] F Laser processing direction

[0032] W workpiece

[0033] W1 surface (image plane)

[0034] A First Laser

[0035] Sai workpiece side first light spot

[0036] Diameter of the first spot on the Dai workpiece side

[0037] Saj detection side, first light spot

[0038] The diameter of the first spot on the Daj detection side

[0039] B-second laser

[0040] Sbi workpiece side second light spot

[0041] Dbi workpiece side second spot diameter

[0042] Sbj detection side second spot

[0043] Dbj detection side second spot diameter

[0044] 1 Laser processing system

[0045] 2. First laser oscillator

[0046] 2a 6th photodetector

[0047] 3. Second laser oscillator

[0048] 3a 7th photodetector

[0049] 4. First fiber

[0050] 5. Second fiber optic cable

[0051] 10 laser processing heads

[0052] 20th collimating lens

[0053] 21 Second collimating lens

[0054] 30° bend mirror

[0055] 40-color mirror

[0056] 50 Workpiece-side condenser lens

[0057] 60 Image Sensors (5th Photodetector)

[0058] 61 Light-receiving surface

[0059] 70 detection side focusing lens

[0060] 72 ND filter

[0061] 80° Reflector Side Actuator (Adjustment Unit)

[0062] 81. First lens-side actuator (adjustment unit)

[0063] 82 Second lens side actuator (adjustment unit)

[0064] 91a Third Photodetector

[0065] 91b First Photodetector

[0066] 92a Second Photodetector

[0067] 92b, fourth photodetector. Detailed Implementation

[0068] The embodiments of the present disclosure will now be described with reference to the accompanying drawings. Furthermore, the following description of preferred embodiments is merely illustrative and is not intended to limit the present disclosure, its applications, or its uses.

[0069] (Implementation Method 1)

[0070] [Structure of a laser processing system]

[0071] Figure 1 This refers to the laser processing system (laser processing apparatus) 1 involved in this embodiment. The laser processing system 1 is a hybrid laser processing system that uses two lasers with different wavelengths to perform laser processing such as cutting, welding, and drilling on the workpiece W.

[0072] The laser processing system 1 includes a laser processing head (laser irradiation head) 10, a first laser oscillator 2 and a second laser oscillator 3, a first optical fiber 4 and a second optical fiber 5, a robotic arm 6, and a control device 7.

[0073] Laser oscillator 2 emits laser light A. Laser oscillator 3 emits laser light B. Laser light A and laser light B have different wavelengths. Laser light A is near-infrared light with a wavelength of approximately 900nm to 1200nm. Laser light B is blue light with a wavelength of approximately 400nm to 450nm. Generally, near-infrared light is used in laser processing, but due to its good absorption rate in copper, blue light has also been used in laser processing in recent years. Alternatively, laser light B can be set to green light (wavelength: approximately 450nm to 550nm).

[0074] The first optical fiber 4 transmits the first laser A from the first laser oscillator 2 to the laser processing head 10. The second optical fiber 5 transmits the second laser B from the second laser oscillator 3 to the laser processing head 10.

[0075] The laser processing head 10 irradiates at least one of a first laser A and a second laser B onto the surface W1 of the workpiece W. In this case, the optical axis of the first laser A and the optical axis of the second laser B are set to be the same as those of the workpiece W. For example, when both the first laser A and the second laser B irradiate the surface W1 of the workpiece W simultaneously, the workpiece W is irradiated with the optical axis of the first laser A coinciding with the optical axis of the second laser B. The details of the laser processing head 10 will be described later.

[0076] The robotic arm 6 has a laser processing head 10 mounted on its front end, which moves the laser processing head 10. The control device 7 controls the movement of the robotic arm 6 and the oscillation of lasers A and B based on the laser oscillators 2 and 3. The control device 7 can also control the movement of the actuators inside the laser processing head 10, which will be described later.

[0077] [Structure of the laser processing head]

[0078] Figure 2 This shows the internal structure of the laser processing head 10. Additionally, Figure 2In the orthogonal coordinate system, X, Y, and Z represent directions. X and Y are the horizontal directions (front, back, left, and right), and Z is the vertical direction (up and down). Furthermore, the direction of extension of the optical axis (the imaginary ray representing the beam of each laser A and B) is called the "optical axis direction." The optical axis direction is not always fixed in the orthogonal coordinate system X, Y, Z; it can change according to the movement of each laser A and B.

[0079] The laser processing head 10 uses a focusing optical system disposed inside the housing 11 to focus the first laser A and the second laser B onto the workpiece W. The laser processing head 10, as the focusing optical system, includes: a first collimating lens 20, a second collimating lens 21, a deflecting mirror 30, a dichroic mirror 40, and a workpiece-side focusing lens 50. Furthermore, the laser processing head 10 includes: a mirror-side actuator 80 as part of an adjustment unit, a first lens-side actuator 81 as part of an adjustment unit, and a second lens-side actuator 82 as part of an adjustment unit.

[0080] The laser processing head 10 includes: a third photodetector 91a, a first photodetector 91b, a second photodetector 92a, and a fourth photodetector 92b. Furthermore, the laser processing head 10 includes: an image sensor (fifth photodetector) 60, a detection-side focusing lens 70, and an aperture 71. The configuration of the first to fourth photodetectors 91b, 92a, 91a, and 92b within the housing 11, as well as the function of each photodetector, will be detailed later.

[0081] A first light entrance 12a and a second light entrance 12b are provided on the upper side in the Z direction of the housing 11. The first light entrance 12a and the second light entrance 12b are provided at a predetermined interval. A first optical fiber 4 is connected to the first light entrance 12a, and a first laser A is incident into the interior of the housing 11 through the first light entrance 12a. A second optical fiber 5 is connected to the second light entrance 12b, and a second laser B is incident into the interior of the housing 11 through the second light entrance 12b. Sometimes, the first light entrance 12a and the second light entrance 12b are collectively referred to as the entrance section 12.

[0082] Furthermore, a light irradiation port (irradiation section) 13 is provided on the lower side of the housing 11 in the Z direction. The first laser A and the second laser B irradiate the surface W1 of the workpiece W through the protective glass 14 provided in the light irradiation port 13.

[0083] A partition wall 11a is provided in the housing 11. In the Y direction, the partition wall 11a is located between the first light entrance 12a and the second light entrance 12b. In the Z direction, it extends from the upper inner wall of the housing 11 to the vicinity of the first collimating lens 20 and the second collimating lens 21. The partition wall 11a separates the optical path of the first laser A entering from the first light entrance 12a from the optical path of the second laser B entering from the second light entrance 12b.

[0084] The first collimating lens 20 converts the first laser A into a parallel ray. The second collimating lens 21 converts the second laser B into a parallel ray. In addition, the first laser A and the second laser B travel parallel to each other in the Z direction until they are incident on the first collimating lens 20 and the second collimating lens 21, respectively.

[0085] The deflector 30 changes the direction in which the optical axis of the second laser B, which is parallel to the optical axis of the first laser A, intersects with the optical axis of the first laser A, specifically, in an orthogonal direction (Y direction).

[0086] The dichroic mirror 40 is a reflector that transmits most of light with a specific wavelength bandwidth and reflects most of light with wavelength bandwidths outside that bandwidth. In this embodiment, the dichroic mirror 40 transmits most of the first laser A incident from the back side 41 to the surface side 42 in a substantially straight direction, and reflects most of the second laser B incident from the surface side 42 to the surface side 42 in a substantially right-angle direction. On the other hand, the dichroic mirror 40 reflects the remaining portion of the first laser A incident from the back side 41 to the back side 41 in a substantially right-angle direction, and transmits the remaining portion of the second laser B incident from the surface side 42 to the back side 41 in a substantially straight direction.

[0087] A light irradiation port 13 is disposed on the optical axis travel side, where most of the first laser A transmitted through the dichroic mirror 40 and most of the second laser B reflected by the dichroic mirror 40 are transmitted toward the workpiece W side. That is, the dichroic mirror 40 transmits most of the first laser A toward the workpiece W side and reflects most of the second laser B toward the workpiece W side.

[0088] Furthermore, the term "majority" for each laser A and B refers, for example, to approximately 95% to 99.9% of each laser A and B incident before the dichroic mirror 40, based on energy conversion. The term "remaining portion" for each laser A and B refers, for example, to approximately 0.1% to 5% of each laser A and B incident before the dichroic mirror 40, based on energy conversion.

[0089] A workpiece-side condenser lens 50 is positioned between the dichroic mirror 40 and the workpiece W along the optical axis. The workpiece-side condenser lens 50 focuses the first laser A and the second laser B. The focused first laser A and the second laser B are then directed onto the surface W1 of the workpiece W via the light irradiation port 13. The workpiece-side condenser lens 50 may also have a chromatic aberration correction function. In this case, the focusing positions of the first laser A and the second laser B transmitted through the workpiece-side condenser lens 50 are approximately aligned in the Z-direction.

[0090] The image sensor (fifth photodetector) 60 is an imaging element that converts the brightness and darkness of light imaged on its light-receiving surface 61 into the amount of electrical charge, reads it, and converts it into an electrical signal. The image sensor 60 is disposed on the back side 41 of the dichroic mirror 40. Specifically, the image sensor 60 is disposed on the optical axis travel side of the remaining portion of the first laser A reflected by the dichroic mirror 40 and the remaining portion of the second laser B transmitted through the dichroic mirror 40. That is, the image sensor 60 receives light from the remaining portion of the first laser A reflected by the dichroic mirror 40 and the remaining portion of the second laser B transmitted through the dichroic mirror 40 through the light-receiving surface 61, respectively.

[0091] Aperture 71 is positioned between the dichroic mirror 40 and the detection-side condenser lens 70 along the optical axis.

[0092] A detection-side condenser lens 70 is positioned between the aperture 71 and the image sensor 60 along the optical axis. The detection-side condenser lens 70 focuses the light from the first laser A and the second laser B. Furthermore, the detection-side condenser lens 70 directs the focused light from the first laser A and the second laser B onto the light-receiving surface 61 of the image sensor 60. The detection-side condenser lens 70 may also have a chromatic aberration correction function. In this case, the focusing positions of the first laser A and the second laser B, which have been transmitted through the detection-side condenser lens 70, are approximately aligned in the Y direction.

[0093] The size, curvature, and distance between the detection-side condenser lens 70 and the image sensor 60 are set to correspond to the focusing state of the first laser A irradiating the surface W1 of the workpiece W. In other words, the focusing state of the first laser A irradiating the light-receiving surface 61 of the image sensor 60 corresponds to the focusing state of the first laser A irradiating the surface W1 of the workpiece W.

[0094] Similarly, the size, curvature, and distance between the detection-side condenser lens 70 and the image sensor 60 are set to correspond to the focusing state of the second laser B irradiating the surface W1 of the workpiece W. In other words, the focusing state of the second laser B irradiating the light-receiving surface 61 of the image sensor 60 corresponds to the focusing state of the second laser B irradiating the surface W1 of the workpiece W.

[0095] For example, if the spot diameter (detection-side first spot diameter Daj) of the first laser A increases on the light-receiving surface 61 of the image sensor 60, then the spot diameter (workpiece-side first spot diameter Dai) of the first laser A irradiating the surface W1 of the workpiece W also increases. If the focusing position of the second laser B shifts on the light-receiving surface 61 of the image sensor 60, then the focusing position of the second laser B irradiating the surface W1 of the workpiece W also shifts in the same way. Furthermore, in this embodiment, the term "spot diameter" refers to the diameter of the laser in any image plane (e.g., the surface W1 of the workpiece W, the light-receiving surface 61 of the image sensor 60), and is not necessarily limited to the diameter at the laser's focusing point.

[0096] The mirror-side actuator 80 changes the tilt angle of the deflector 30. The mirror-side actuator 80 is, for example, composed of a tilting shaft and a motor that rotates the tilting shaft. By changing the tilt angle of the deflector 30 based on the mirror-side actuator 80, the orientation of the optical axis of the second laser B, which is bent by the deflector 30, changes. Consequently, the focusing position of the second laser B changes.

[0097] The first lens-side actuator 81 moves the first collimating lens 20 along the optical axis (Z direction). The first lens-side actuator 81 is, for example, a linear motor. The second lens-side actuator 82 moves the second collimating lens 21 along the optical axis (Z direction). The second lens-side actuator 82 is, for example, a linear motor. By moving the collimating lenses 20 and 21 along the optical axis (Z direction) based on the respective lens-side actuators 81 and 82, the spot diameters of the first laser A and the second laser B (described later) change respectively.

[0098] In addition, when each collimating lens 20 and 21 is moved in the optical axis direction (Z direction) by each lens-side actuator 81 and 82, each collimating lens 20 and 21 may not move straight in the optical axis direction (Z direction), but may move slightly or tilt slightly in the horizontal direction (X direction and Y direction) orthogonal to the optical axis direction.

[0099] As described above, at least a portion of the plurality of optical components, in this case a deflector 30 and a dichroic mirror 40, are disposed inside the housing 11 to alter the optical path of the second laser B so that the optical axis of the first laser A emitted from the light irradiation port 13 is substantially aligned with the optical axis of the second laser B.

[0100] [Structure of an image sensor]

[0101] Figure 3 The pixel structure of an image sensor is illustrated schematically. Figure 4 This indicates the relationship between the light-receiving efficiency of an RGB pixel and its wavelength.

[0102] like Figure 3As shown, the image sensor 60 arranges a total of four pixels as a unit: pixels that receive near-infrared or infrared light (hereinafter referred to as N pixels), pixels that receive red light (hereinafter referred to as R pixels), pixels that receive green light (hereinafter referred to as G pixels), and pixels that receive blue light (hereinafter referred to as B pixels). Specifically, compared to the known Bayer array, a color filter arrangement in which one G pixel is replaced by an N pixel.

[0103] like Figure 4 As shown, the R pixel exhibits high quantum efficiency in photoelectric conversion of light with a wavelength range of approximately 600nm to 850nm, efficiently converting typical red light (around 600nm to 700nm) into electrical signals. The G pixel demonstrates high quantum efficiency in photoelectric conversion of light with a wavelength range of approximately 500nm to 550nm, efficiently converting typical green light (around 500nm to 550nm) into electrical signals. The B pixel demonstrates high quantum efficiency in photoelectric conversion of light with a wavelength range of approximately 400nm to 500nm, efficiently converting typical blue light (around 420nm to 480nm) into electrical signals. Furthermore, although not illustrated, the N pixel demonstrates high quantum efficiency in photoelectric conversion of light with a wavelength range of approximately 900nm to 1200nm, efficiently converting near-infrared light or infrared light (around 900nm to 1200nm) into electrical signals.

[0104] As described above, the wavelength of the first laser A is approximately 900nm to 1200nm, and the wavelength of the second laser B is approximately 400nm to 450nm. Therefore, by using... Figure 3 The image sensor 60 shown can reliably convert the first laser A and the second laser B, which are transmitted through the detection-side focusing lens 70, into electrical signals. Furthermore, by appropriately setting the size of each pixel, the two-dimensional distribution of the first laser A and the second laser B at the light-receiving surface 61 can be determined. As described later, based on this two-dimensional distribution and the spot diameters of the first laser A and the second laser B at the light-receiving surface 61, the focusing position and spot diameter of the first laser A and the second laser B at the surface W1 of the workpiece W can be corrected.

[0105] Furthermore, from the perspective of reliably converting the first laser A and the second laser B into electrical signals respectively, for example, it is also possible to... Figure 3 The R pixel shown is replaced with a B pixel, and the G pixel is further replaced with an N pixel. In other words, it is also possible to arrange only the B and N pixels periodically. Furthermore, if the second laser B is green light, the B pixel can also be replaced with a G pixel.

[0106] [Monitoring and adjusting the focus status]

[0107] In actual laser processing of workpiece W, it is impossible to monitor the focusing states of the first laser A and the second laser B at surface W1. However, according to this embodiment, as described above, the focusing states of the first laser A and the second laser B irradiating the light-receiving surface 61 of the image sensor 60 correspond to the focusing states of the first laser A and the second laser B irradiating the surface W1 of the workpiece W. In other words, based on the spot images of the first laser A and the second laser B irradiating the light-receiving surface 61 of the image sensor 60, the focusing state at surface W1 of the workpiece W can be monitored.

[0108] Figure 5A This is an example showing the spot images of the first and second lasers focused onto the light-receiving surface of an image sensor. Figure 5B An example showing the spot images of the first and second lasers focused on the surface of a workpiece.

[0109] As will be described later, by adjusting and appropriately setting the configuration of the various optical components inside the laser processing head 10, such as... Figure 5B As shown, the first laser A and the second laser B are focused uniformly or nearly uniformly on the surface W1 of the workpiece W. Furthermore, the first workpiece-side spot Sai of the first laser A and the second workpiece-side spot Sbi of the second laser B are both adjusted to suitable machining dimensions. The diameter Dai of the first workpiece-side spot of the first laser A and the diameter Dbi of the second workpiece-side spot of the second laser B are also adjusted to suitable machining dimensions.

[0110] Based on the images of the first laser A and the second laser B acquired by the image sensor 60, the focusing positions of the first laser A and the second laser B at the surface W1 of the workpiece W can be adjusted.

[0111] For example, if the focusing positions of the first laser A and the second laser B are offset due to the optical axis misalignment of the two lasers, the mirror-side actuator 80 can be tilted to align the focusing positions of the two lasers. Furthermore, for example, if the spot image of the first laser A illuminating the light-receiving surface 61 of the image sensor 60 is out of focus, the first lens-side actuator 81 is driven to eliminate the defocus. In this way, the first laser A can be focused on the surface W1 of the workpiece W. Similarly, if the spot image of the second laser B illuminating the light-receiving surface 61 of the image sensor 60 is out of focus, the second lens-side actuator 82 is driven to eliminate the defocus. In this way, the second laser B can be focused on the surface W1 of the workpiece W.

[0112] [Structure of photodetectors 1 through 4]

[0113] Figure 6AThe structure of the first and third photodetectors is schematically shown. Figure 6B The structure of the second and fourth photodetectors is schematically shown.

[0114] like Figure 6A As shown, the first photodetector 91b includes a photodiode 91b1 and a wavelength selective filter 91b2. The wavelength selective filter 91b2 is configured to transmit light in the second band, which contains wavelengths of blue light, and to block light of other wavelengths. The third photodetector 91a includes a photodiode 91a1 and a wavelength selective filter 91a2. The wavelength selective filter 91a2 is configured to transmit light in the first band, which contains wavelengths of near-infrared or infrared light, and to block light of other wavelengths.

[0115] like Figure 6B As shown, the second photodetector 92a includes a photodiode 92a1 and a wavelength selective filter 92a2. The wavelength selective filter 92a2 is configured to transmit light in the first band containing near-infrared or infrared wavelengths and block light of other wavelengths. The fourth photodetector 92b includes a photodiode 92b1 and a wavelength selective filter 92b2. The wavelength selective filter 92b2 is configured to transmit light in the second band containing blue light wavelengths and block light of other wavelengths.

[0116] As described later, the first to fourth photodetectors 91b, 92a, 91a, and 92b need to be positioned to receive light from the first laser A or the second laser reflected by optical components, such as protective glass, inside the workpiece W or housing 11. Therefore, as Figure 2 As shown, the first photodetector 91b and the third photodetector 91a are disposed around the optical path of the first laser A incident from the first light entrance port 12a. The second photodetector 92a and the fourth photodetector 92b are disposed around the optical path of the second laser B incident from the second light entrance port 12b.

[0117] Furthermore, a partition 11a is provided between the first photodetector 91b and the third photodetector 91a and the second photodetector 92a and the fourth photodetector 92b. In this way, the light paths of the first photodetector 91b and the third photodetector 91a that can receive light are separated from the light paths of the second photodetector 92a and the fourth photodetector 92b.

[0118] In this embodiment, the first band refers to the range of 900nm to 1200nm, and the second band refers to the range of 400nm to 600nm. However, it is not particularly limited to these. As described later, the first to fourth photodetectors 91b, 92a, 91a, and 92b respectively receive light from the first laser A or the second laser reflected by optical components inside the workpiece W or the housing 11, such as protective glass. However, when the laser is irradiated by metal, it may interact with plasma on the surface of the metal, causing a wavelength shift in the reflected light. The first to fourth photodetectors 91b, 92a, 91a, and 92b need to be able to receive the reflected light with such a wavelength shift.

[0119] Therefore, it is necessary to ensure that the wavelength bandwidth of the first photodetector 91b and the fourth photodetector 92b that can receive light is the same as or wider than the wavelength bandwidth of the second laser B, for example, designated as the second band. Similarly, it is necessary to ensure that the wavelength bandwidth of the second photodetector 92a and the third photodetector 91a that can receive light is the same as or wider than the wavelength bandwidth of the first laser A, for example, designated as the first band.

[0120] In other words, the first photodetector 91b is positioned around the optical path of the first laser A to receive light from the second laser B reflected by the workpiece W, etc. The second photodetector 92a is positioned around the optical path of the second laser B to receive light from the first laser A reflected by the workpiece W, etc. The third photodetector 91a is positioned around the optical path of the first laser A to receive light from the first laser A reflected by the workpiece W, etc. The fourth photodetector 92b is positioned around the optical path of the second laser B to receive light from the second laser B reflected by the workpiece W, etc.

[0121] Furthermore, wavelength selective filters 91a2 and 92a2 can also transmit light of the first band and wavelengths longer than the first band, while blocking light with a wavelength bandwidth shorter than the first band. The light-receiving sensitivity for the second band can be set to a specified level. Similarly, wavelength selective filters 91b2 and 92b2 can also transmit light of the second band and wavelengths shorter than the second band, while blocking light with a wavelength bandwidth longer than the second band. The light-receiving sensitivity for the first band can be set to a specified level.

[0122] In addition, Figure 6A , 6B In the example shown, the first to fourth photodetectors 91b, 92a, 91a, and 92b include photodiodes and wavelength-selective filters disposed independently therewith, but are not particularly limited to this; wavelength-selective filters can also be integrated by forming them directly on the surface of the photodiodes. Furthermore, the photodiodes 91b1, 91a1, 92a1, and 92b1 can also be a photodiode array.

[0123] [Steps for troubleshooting malfunctions in laser processing systems]

[0124] Figure 7 This schematically illustrates the state of the reflected light when the first laser beam is directed at the workpiece. Figure 8 This schematically illustrates the state of the reflected light when the second laser is directed at the workpiece. Figure 9 This is an example of the output of the first to fourth photodetectors when the first and second lasers are irradiated onto the workpiece.

[0125] Additionally, for ease of explanation, in Figure 7 , 8 The diagram only shows the first to fourth photodetectors 91b, 92a, 91a, 92b, deflection mirror 30, dichroic mirror 40, and protective glass 14 among the components constituting the laser processing head 10.

[0126] As described, by monitoring the processing status of the workpiece W during laser processing and detecting abnormalities in the laser processing system 1, it is possible to suppress the occurrence of processing abnormalities and the reduction of processing quality. Examples of abnormalities in the laser processing system 1 include, for instance, abnormalities in the internal optical components of the laser processing head 10, and abnormalities in the first optical fiber 4 and the second optical fiber 5. Furthermore, abnormalities in the output of the first laser oscillator 2 and the second laser oscillator 3 are also included.

[0127] However, inside the laser processing head 10 that irradiates the workpiece W with the first laser A and the second laser B, there is a mixture of reflected light from the workpiece W, vignetting light from optical components such as the protective glass 14, and other components. Furthermore, it includes components caused by the first laser A and components caused by the second laser B, respectively.

[0128] As already described, if a photodetector is installed only inside the laser processing head 10 as disclosed in Patent Document 1, it is impossible to smoothly divide each component, and it is difficult to determine the processing state of the workpiece W and the state of the optical components inside the laser processing head 10.

[0129] Therefore, in the laser processing head 10 of this embodiment, the first to fourth photodetectors 91b, 92a, 91a, and 92b are respectively arranged at the positions inside the housing 11. Furthermore, the light detection function of the first to fourth photodetectors 91b, 92a, 91a, and 92b, specifically the wavelength of light that can be received, is set as described above.

[0130] In this way, based on the intensity of the reflected light detected by the first to fourth photodetectors 91b, 92a, 91a, and 92b respectively, the processing state of the workpiece W and the state of the internal optical components of the laser processing head 10 can be determined. In this embodiment, the process of determining the processing state of the workpiece W during laser welding is described.

[0131] When laser welding is performed on workpiece W, if a welding defect occurs, the surface roughness W1 of workpiece W changes compared to a normal area. Therefore, the intensity of the reflected light from workpiece W also changes. For example, if the intensity of the reflected light from workpiece W increases by a specified value or more, it can be determined that a welding abnormality has occurred.

[0132] When the first laser A is irradiated onto the surface W1 of the workpiece W, such as Figure 7 As shown, this produces several components of reflected light.

[0133] First, the reflected light from the workpiece W returns to its original optical path and passes through the dichroic mirror 40, returning to the first light entrance 12a. Alternatively, it may return to the first laser oscillator 2 via the first optical fiber 4. This returned light component is designated A0.

[0134] On the other hand, the surface W1 of the workpiece W is not necessarily flat. In addition, the surface of the weld bead (not shown) formed during welding also has unevenness. Therefore, the reflected light from the workpiece W is scattered, producing a returned light component A1 that does not remain unchanged and travels along the original optical path toward the first light entrance 12a.

[0135] Furthermore, if the surface of the protective glass 14 is contaminated due to sputtering or the like, a portion of the first laser A will also be reflected from the surface of the protective glass 14, producing a returned light component A2 (hereinafter sometimes referred to as the vignetting component A2). The vignetting component A2 is transmitted through the dichroic mirror 40 and faces the first light entrance port 12a. In addition, not limited to the protective glass 14, optical components in the optical path of the first laser A disposed inside the housing 11 will each produce the same reflected returned light (vignetting light).

[0136] On the other hand, as described, the dichroic mirror 40 has a limited reflectivity (e.g., a few percent) for the first laser A. Therefore, a portion of the reflected light from the workpiece W is reflected by the dichroic mirror 40 and the deflector 30 toward the second light entrance 12b. This reflected light component is designated A3. Similarly, a portion of the reflected light from the protective glass 14 is reflected by the dichroic mirror 40 and the deflector 30 toward the second light entrance 12b. This reflected light component is designated A4.

[0137] Furthermore, when the second laser B is irradiated onto the surface W1 of the workpiece W, several components of reflected light are also generated. Figure 8 The returned light components B0 to B4 shown are... Figure 7The returned light components A0 to A4 are shown respectively. Furthermore, the dichroic mirror 40 has a limited transmittance (e.g., 0. several percent) for the second laser B. Therefore, the optical paths of each of the returned light components B0 to B4 are not the same as the optical paths of each of the returned light components A0 to A4.

[0138] For example, the returning light component B0 reflected by the surface W1 of the workpiece W is reflected by the dichroic mirror 40 and the deflecting mirror 30 and returns to the second light entrance 12b. Furthermore, it may also return to the second laser oscillator 3 via the second optical fiber 5. The returning light component B2 (hereinafter sometimes referred to as the vignetting component B2) reflected by the surface of the protective glass 14 is reflected by the dichroic mirror 40 and the deflecting mirror 30 and returns to the second light entrance 12b.

[0139] Thus, the reflected light of the first laser A, reflected by the workpiece W and the protective glass 14, is divided into components A0, A1, and A2 toward the first light entrance 12a and components A3 and A4 toward the second light entrance 12b. Similarly, the reflected light of the second laser B, reflected by the workpiece W and the protective glass 14, is divided into components B3 and B4 toward the first light entrance 12a and components B0, B1, and B2 toward the second light entrance 12b. However, typically, the reflected light from the protective glass 14 is very small compared to the reflected light from the workpiece W. This is because the reflectivity of the laser at the surface of the protective glass 14 is extremely small compared to the reflectivity at the surface W1 of the workpiece W. Furthermore, not only the protective glass 14, but also other optical components have reflectivities that are smaller than the reflectivity at the surface W1 of the workpiece W. Therefore, the reflected light components A4 and B4 are extremely small compared to the other reflected light components and are generally negligible.

[0140] Therefore, the first photodetector 91b, located around the optical path of the first laser A, can detect component B3 of the returned light component. Furthermore, the third photodetector 91a can detect both the returned light component A1 and the vignetting component A2. The second photodetector 92a, located around the optical path of the second laser B, can detect component A3 of the returned light component. Furthermore, the fourth photodetector 92b can detect both the returned light component B1 and the vignetting component B2.

[0141] Therefore, when it is necessary to improve the signal-to-noise ratio (S / N ratio) for detecting the reflected light of the first laser A at the surface W1 of workpiece W, using the output signal of the second photodetector 92a is more advantageous than using the output signal of the third photodetector 91a. This is because the output signal of the third photodetector 91a contains the reflected light component from the protective glass 14, namely the vignetting component A2. For the same reason, when it is necessary to improve the S / N ratio for detecting the reflected light of the second laser B at the surface W1 of workpiece W, using the output signal of the first photodetector 91b is more advantageous than using the output signal of the fourth photodetector 92b.

[0142] For example, the output of the first laser A is set to 6000W, and the output of the second laser B is set to 1000W. In addition, the transmittance of the first laser A at the dichroic mirror 40 is set to 99.9% (and the reflectance is set to 0.1%), and the reflectance of the second laser B is set to 99.9% (and the transmittance is set to 0.1%).

[0143] In this case, such as Figure 9 As shown, in the path toward the workpiece W, the power of the first laser A and the second laser B are reduced by 1% respectively. Furthermore, the power of the vignetted laser in the optical component including the protective glass 14 is approximately 1% of that of the first laser A and the second laser.

[0144] On the other hand, most of the first laser A, reflected by the surface W1 of the workpiece W, is transmitted through the beam splitter 40, while a portion is reflected by the dichroic mirror. If we assume the returned light component A0 is zero, then the former is equivalent to the returned light component A1 and is detected by the third photodetector 91a. The latter is equivalent to the returned light component A3 (which also actually includes the returned light component A4) and is detected by the second photodetector 92a.

[0145] Furthermore, a large portion of the first laser A, which is vignetted on the surface of the optical component, is also transmitted through the beam splitter 40. Therefore, this component, namely the vignetted component A2, is also detected by the third photodetector 91a.

[0146] Therefore, when the first laser A reflected from the surface W1 of the workpiece W is to be detected by the third photodetector 91a, the vignetting component A2 is also detected, thus reducing the S / N ratio. Figure 9 It can be seen that, relative to the signal component caused by the return light component A1, which is a signal component, the noise component caused by the vignetting component A2 is about 20%.

[0147] On the other hand, the first laser A, which is halogenated on the surface of the optical component, does not actually incident on the second photodetector 92a. Therefore, the power of the first laser A reflected by the surface W1 of the workpiece W can be accurately evaluated based on the output signal of the second photodetector 92a.

[0148] Similarly, most of the first laser A reflected by the surface W2 of the workpiece W is reflected by the beam splitter 40, while a portion is transmitted through the dichroic mirror. If we assume the returned light component B0 is zero, then the former corresponds to the returned light component B1 and is detected by the first photodetector 91b. The latter corresponds to the returned light component B3 (which actually also includes the returned light component B4) and is detected by the fourth photodetector 92b.

[0149] However, most of the second laser B, which is vignetted on the surface of the optical component, is also reflected by the beam splitter 40. Therefore, the vignetted component B2, as this component, is also detected by the fourth photodetector 92b.

[0150] Therefore, when the second laser B reflected by the surface W1 of the workpiece W is to be detected by the fourth photodetector 92b, the vignetting component B2 is also detected, thus reducing the S / N ratio. Figure 9 It can be seen that, relative to the signal component caused by the return light component B1, which is a signal component, the noise component caused by the vignetting component B2 is about 20%.

[0151] On the other hand, the second laser B, which is halogenated on the surface of the optical component, does not actually incident on the first photodetector 91b. Therefore, based on the output signal of the first photodetector 91b, the power of the second laser B reflected by the surface W1 of the workpiece W can be accurately evaluated.

[0152] [Effects, etc.]

[0153] As described above, the laser processing head 10 according to this embodiment has: a housing 11 and a plurality of optical components disposed inside the housing 11.

[0154] The housing 11 includes a first light entrance port 12a for the first laser A, a second light entrance port 12b for the second laser B, and a light irradiation port 13 for emitting the first laser A and the second laser B to the outside. Furthermore, the housing 11 includes a partition wall 11a separating the optical path of the first laser A entering through the first light entrance port 12a from the optical path of the second laser B entering through the second light entrance port 12b. Additionally, the wavelength of the second laser B is shorter than the wavelength of the first laser A.

[0155] The laser processing head 10 further includes: a first photodetector 91b disposed around the optical path of the first laser A incident from the first light entrance 12a, and a second photodetector 92a disposed around the optical path of the second laser B incident from the second light entrance 12b.

[0156] The first photodetector 91b is positioned on the side opposite to the second photodetector 92a, sandwiching the partition wall 11a. The first photodetector 91b receives light in the second band containing the wavelength of the second laser B, while the second photodetector 92a receives light in the first band containing the wavelength of the first laser A.

[0157] At least a portion of a plurality of optical components are disposed inside the housing 11 to alter the optical path of the second laser B, such that the optical axis of the first laser A emitted from the light irradiation port 13 is substantially aligned with the optical axis of the second laser B.

[0158] According to this embodiment, by providing a second photodetector 92a capable of receiving light from the first laser A around the optical path of the second laser B, the power of the first laser A reflected by the surface W1 of the workpiece W can be accurately evaluated. Therefore, the state of the surface W1 of the workpiece W can be accurately inferred, and the occurrence of processing defects and reduction in processing quality when the first laser A is irradiated onto the workpiece W can be suppressed.

[0159] Similarly, by providing a first photodetector 91b around the optical path of the first laser A to receive light from the second laser B, the power of the second laser B reflected by the surface W1 of the workpiece W can be accurately evaluated. Therefore, the state of the surface W1 of the workpiece W can be accurately inferred, and the occurrence of processing defects and reduction in processing quality when the second laser B is irradiated onto the workpiece W can be suppressed.

[0160] Furthermore, the first photodetector 91b is configured to receive light in a second band with a bandwidth wider than that of the second laser B. The second photodetector 92a is configured to receive light in a first band with a bandwidth wider than that of the first laser A. Thus, even if the wavelengths of the first laser A and the second laser B are offset at the surface W1 of the workpiece W, the reflected light can be reliably detected.

[0161] Furthermore, the first band is preferably 900 nm or higher and 1200 nm or lower. In addition, the second band is preferably 400 nm or higher and 700 nm or lower.

[0162] When using near-infrared light as the first laser A and blue light as the second laser, by setting the ranges of the first and second bands respectively, reflected light can be reliably detected even if the wavelength of the laser at the surface W1 of the workpiece W shifts. Furthermore, when using infrared light as the first laser A, the first band can be set to 800 nm or more and 1200 nm or less. Similarly, when using green light as the second laser B, the second band can be set to 500 nm or more and 750 nm or less.

[0163] Furthermore, by aligning the optical axis of the first laser A emitted from the light irradiation port 13 with the optical axis of the second laser B, the processing quality can be maintained even when laser processing is performed on the workpiece W with the first laser A and the second laser B overlapping.

[0164] The plurality of optical components include at least: a deflecting mirror 30, which is disposed in the optical path of the second laser B and reflects the second laser B to change the optical path; a dichroic mirror 40, which is disposed in the optical path of the first laser A and in the optical path of the second laser B reflected by the deflecting mirror 30; and a protective glass 14, which covers the light irradiation port 13.

[0165] Dichroic mirror 40 transmits most of the first laser A and directs it toward the light irradiation port 13, and reflects the remaining portion of the first laser A and directs it toward the aperture 71. Furthermore, aperture 71 reflects most of the second laser B and directs it toward the light irradiation port 13, and transmits the remaining portion of the second laser B and directs it toward the aperture 71.

[0166] In this way, the optical axis of the first laser A is made approximately aligned with the optical axis of the second laser B, allowing both lasers to exit from the light irradiation port 13. Therefore, when laser processing is performed on the workpiece W with the first laser A and the second laser B aligned, the processing quality can be maintained.

[0167] Inside the housing 11, in the Z direction, a first collimating lens 20 is disposed between the first light entrance 12a and the dichroic mirror 40. A second collimating lens 21 is disposed between the second light entrance 12b and the deflecting mirror 30. A workpiece-side condenser lens 50 is disposed between the dichroic mirror 40 and the light irradiation port 13.

[0168] The first collimating lens 20 parallelizes the first laser A and directs it onto the dichroic mirror 40. The second collimating lens 21 parallelizes the second laser B and directs it onto the deflecting mirror 30. The workpiece-side focusing lens 50 focuses the incident first laser A and second laser B onto specified focusing positions.

[0169] According to this embodiment, by having the above structure, the optical axes of the first laser A and the second laser B directed from the light irradiation port 13 towards the workpiece W can be made substantially aligned. Furthermore, the first laser A and the second laser B can each focus on the surface W1 of the workpiece W. Thus, the focusing positions of the first laser A and the second laser B at the surface W1 of the workpiece W can be made substantially aligned.

[0170] The plurality of optical components include at least: an aperture 71, which is disposed in the optical path of the second laser B transmitted through the dichroic mirror 40 and the optical path of the first laser A reflected by the dichroic mirror 40; and a detection-side condenser lens 70, which is disposed in the optical paths of the first laser A and the second laser B passing through the aperture 71.

[0171] An image sensor (fifth photodetector) 60 is configured inside the housing 11 at a position that can receive light from the first laser A and the second laser B, which are transmitted through the detection-side condenser lens 70.

[0172] In this way, the light spots of the first laser A (detection-side first light spot Saj) and the second laser B (detection-side second light spot Sbj) can be imaged onto the light-receiving surface 61 of the image sensor 60. By evaluating the images of the detection-side first light spot Saj and the detection-side second light spot Sbj, as well as their respective diameters, namely the detection-side first light spot diameter Daj and the detection-side second light spot diameter Dbj, the focusing state of the first laser A and the second laser B at the surface W1 of the workpiece W can be inferred.

[0173] Furthermore, by means of aperture 71, excess beams can be cut off in the first laser A and the second laser B directed toward the image sensor 60. This reduces the power of the first laser A and the second laser B incident on the light-receiving surface 61, suppressing adverse conditions such as image distortion of the first spot Saj and the second spot Sbj on the detection side, and burn-in of the color filter and other components located on the image sensor 60.

[0174] Furthermore, the image sensor 60 monitors the output of at least one of the first laser A and the second laser B. Based on the monitored output, it is possible to infer the output of the first laser A and / or the second laser B that is irradiated onto the workpiece W during laser processing.

[0175] The image sensor (fifth photodetector) 60 has at least: a plurality of first light-receiving portions (N pixels) for receiving light in a band including the wavelength of the first laser A; and a plurality of second light-receiving portions (B pixels) for receiving light in a band including the wavelength of the second laser B. The plurality of first light-receiving portions and the plurality of second light-receiving portions are periodically arranged on the light-receiving surface 61 of the image sensor 60.

[0176] By configuring the image sensor 60 in this way, the spot images of the first laser A and the second laser B can be acquired at high resolution. This allows for precise adjustment of the focusing positions of the first laser A and the second laser B at the surface W1 of the workpiece W.

[0177] The image sensor 60 is preferably constructed such that four pixels, which receive near-infrared light or infrared light, red light, green light and blue light respectively, are periodically arranged on the light-receiving surface 61.

[0178] Since the pixel structure is a known structure and no specially constructed photodetector is used, the cost increase of the laser processing head 10 can be suppressed. Furthermore, since a known signal processing device can be used to process the output signal of the image sensor 60, the increase in signal processing load can be suppressed.

[0179] The laser processing system (laser processing apparatus) 1 according to this embodiment includes at least: a laser processing head 10, a first laser oscillator 2 that emits a first laser A, and a second laser oscillator 3 that emits a second laser B.

[0180] In addition, the laser processing system 1 includes: a first optical fiber 4 connected to a first optical input port 12a, which transmits a first laser A emitted from a first laser oscillator 2 to a laser processing head 10; and a second optical fiber 5 connected to a second optical input port 12b, which transmits a second laser B emitted from a second laser oscillator 3 to a laser processing head 10.

[0181] The laser processing head 10 irradiates the workpiece W with at least one of the first laser A and the second laser B.

[0182] According to this embodiment, the focusing positions of the first laser A and the second laser B at the surface W1 of the workpiece W can be made approximately the same. Therefore, when laser processing is performed on the workpiece W with the first laser A and the second laser B overlapping, processing accuracy and processing quality can be improved.

[0183] The laser processing system 1 may also include a robotic arm 6 that can move and hold the laser processing head 10. In this way, it is easy to perform laser processing on workpieces W with complex structures.

[0184] The laser processing system 1 is configured to adjust the focusing positions of the first laser A and the second laser B at the surface W1 of the workpiece W based on images of the first laser A and the second laser B acquired by the image sensor 60. In this way, the focusing positions of the first laser A and the second laser B at the surface W1 of the workpiece W can be easily set to the desired positions. This improves the processing accuracy and quality during laser processing.

[0185] The anomaly judgment method involved in this embodiment is an anomaly judgment method for judging the presence or absence of anomalies in the laser processing system 1.

[0186] When the second laser B illuminates the workpiece, the output signal of the first photodetector 91b is used to determine whether there is an abnormality in the processing state of the workpiece W. When the first laser A illuminates the workpiece W, the output signal of the second photodetector 92a is used to determine whether there is an abnormality in the processing state of the workpiece W.

[0187] According to this embodiment, by providing a simple structure with a second photodetector 92a capable of receiving light from the first laser A around the optical path of the second laser B, the state of the surface W1 when the first laser A irradiates the workpiece W can be accurately inferred. Furthermore, by providing a simple structure with a first photodetector 91b capable of receiving light from the second laser B around the optical path of the first laser A, the state of the surface W1 when the second laser B irradiates the workpiece W can be accurately inferred. Therefore, the occurrence of processing defects and the reduction of processing quality during laser processing can be suppressed.

[0188] (Implementation Method 2)

[0189] Figure 10 This illustrates an example of the outputs of the second and third photodetectors when the first laser according to this embodiment is used to irradiate the workpiece.

[0190] As described above, by using the image sensor 60, the power of the first laser A and the second laser B irradiating the workpiece W during laser processing can be evaluated with excellent accuracy.

[0191] However, when performing this evaluation, an aperture 71 and a detection condenser lens 70 need to be installed inside the housing 11 based on the specified configuration relationship with the image sensor 60. These components can also be omitted if further miniaturization of the laser processing head 10 is required.

[0192] In addition, it may be desirable to further evaluate the power of the first laser A and the second laser B by supplementing the detection results of the image sensor 60.

[0193] The laser processing head 10 and laser processing system 1 disclosed herein can simultaneously infer the state of the surface W1 of the workpiece W and evaluate the power of the first laser A and the second laser B based on the output signals of the first to fourth photodetectors 91b, 92a, 91a, and 92b. This will be explained in further detail below. Furthermore, for ease of explanation, in this embodiment, the case where the first laser A is irradiated onto the workpiece W is considered.

[0194] As described above, the third photodetector 91a can detect the reflected light component A1 of the first laser A from the workpiece W. It is assumed that the reflected light component A1 is approximately proportional to the power of the first laser A irradiating the workpiece W.

[0195] Furthermore, although the output signal P3 of the third photodetector 91a contains the vignetting component A2 at the optical component, the ratio of the return light component A1 to the vignetting component A2 can be calculated in advance through experiments, thereby evaluating the contribution of the return light component A1 in the output signal P3.

[0196] Furthermore, in the second photodetector 92a, the reflected light component A3 of the first laser A from the workpiece W can be detected.

[0197] Therefore, based on the output signal P2 of the second photodetector 92a, the power of the reflected light from the first laser A from the workpiece W is inferred. Based on this value, the output signal P3 of the third photodetector 91a is further corrected, thereby enabling the inference of the power of the first laser A irradiating the workpiece W.

[0198] For example, such as Figure 10 As shown in cases 1 and 2, consider the case where no reflected light or very weak reflected light is generated from the workpiece W. In this case, the output signal P2 of the second photodetector 92a is zero. On the other hand, the output signal P3 of the third photodetector 91a increases proportionally to the power of the first laser A irradiating the workpiece W. When the power of the first laser A is 500W, the output signal P3 is 5W (case 1), and when the power of the first laser A is 1000W, the output signal P3 is 10W (case 2).

[0199] Here, we consider the case where reflected light from workpiece W is generated ( Figure 10 (Case 3, 4). Furthermore, through experiments, the ratio of the output signal P2 to the output signal P3 relative to the output of the first laser A is determined beforehand. In this case, P2:P3 is 1:5. In other words, the contribution of the reflected light component from the workpiece W in the output signal P3 is 5 times that of the output signal P2.

[0200] In view of this, in the context of Figure 10 When evaluating the values ​​shown, in case 3 (the power of the first laser A is 1000W), the output signal P2 of the second photodetector 92a is 1W. On the other hand, the output signal P3 of the third photodetector 91a is 15W. If we subtract the amount in the output signal P3 that is related to the reflected light from the workpiece W (=1W×5=5W), the amount directly related to the power of the first laser A irradiating the workpiece W is inferred to be 10W. This value is the same as the output signal P3 in case 2, where the power of the first laser A is the same.

[0201] Similarly, in case 4 (the power of the first laser A is 500W), the output signal P2 of the second photodetector 92a is 0.5W. On the other hand, the output signal P3 of the third photodetector 91a is 7.5W. If we subtract the amount in the output signal P3 that is related to the reflected light from the workpiece W (=0.5W×5=2.5W), the amount directly related to the power of the first laser A irradiating the workpiece W is deduced to be 5W. This value is the same as the output signal P3 in case 1, where the power of the first laser A is the same.

[0202] As can be seen from the above, by using the output signal P2 of the second photodetector 92a to correct the output signal P3 of the third photodetector 91a, the power of the first laser A irradiated onto the workpiece W from the output signal P3 can be inferred.

[0203] Furthermore, it can be clearly stated that when the second laser B is irradiated onto the workpiece W, the power of the reflected light from the second laser B from the workpiece W is inferred based on the output signal P1 of the first photodetector 91b. Based on this value, the output signal P4 of the fourth photodetector 92b is further modified, thereby enabling the inference of the power of the second laser B irradiating the workpiece W.

[0204] Furthermore, when the first laser A and the second laser B are simultaneously irradiated onto the workpiece W, the power of the reflected light from the first laser A originating from the workpiece W is inferred from the output signal P2 of the second photodetector 92a. Based on this value, the output signal P3 of the third photodetector 91a is further corrected, thereby enabling the inference of the power of the first laser A irradiating the workpiece W. Simultaneously, the power of the reflected light from the second laser B originating from the workpiece W is inferred from the output signal P1 of the first photodetector 91b. Based on this value, the output signal P4 of the fourth photodetector 92b is further corrected, thereby enabling the inference of the power of the second laser B irradiating the workpiece W.

[0205] Furthermore, the correction methods for output signals P3 and P4 can be appropriately changed according to the material of workpiece W, specifically the reflectivity of workpiece W for the light in the first laser A band and the second laser B band.

[0206] Furthermore, during prolonged use of the laser processing system 1, the output signals P3 and P4 may increase abnormally, rendering the aforementioned correction relationship invalid. In this case, it is suspected that the vignetting light at the surface of optical components such as the protective glass 14 increases. In other words, it is speculated that contamination adheres to the surface of the optical components, causing the vignetting components A2 and B2 to increase.

[0207] In other words, the anomaly detection method involved in this embodiment can be said to have the following characteristics.

[0208] When the second laser B is irradiated onto the workpiece W, the output signal P1 of the first photodetector 91b is used to determine whether there is an abnormality in the processing state of the workpiece W.

[0209] When the first laser A is irradiated onto the workpiece W, the output signal P2 of the second photodetector 92a is used to determine whether there is an abnormality in the processing state of the workpiece W.

[0210] Based on the output signals P2 and P3 of the second photodetector 92a and the third photodetector 91a, the output of the first laser A is inferred.

[0211] Based on the output signals P1 and P4 of the first photodetector 91b and the fourth photodetector 92b, the output of the second laser B is inferred.

[0212] (Implementation Method 3)

[0213] Figure 11 This diagram shows a general structural diagram of the laser processing system involved in this embodiment. Figure 12 This illustrates an example of the outputs of the second, third, and sixth photodetectors when the first laser beam illuminates the workpiece. Additionally, for ease of explanation, in... Figure 11 In this document, the same symbols are used for the same positions as in Implementation 1, and detailed descriptions are omitted.

[0214] Figure 11 The laser processing system 1 of this embodiment shown has a sixth photodetector 2a in the first laser oscillator 2 and a seventh photodetector 3a in the second laser oscillator 3, which is consistent with... Figure 1 The laser processing system shown is different from the one described.

[0215] The sixth photodetector 2a receives light from the first band, for example, by... Figure 6A The third photodetector 91a shown has the same structure. The sixth photodetector 2a is disposed near the connection between the first laser oscillator 2 and the first optical fiber 4. Furthermore, the sixth photodetector 2a is configured to receive the reflected light of the first laser A transmitted through the first optical fiber 4.

[0216] The seventh photodetector 3a receives light from the second band, for example, it is with... Figure 6A The first photodetector 91b shown has the same structure. The seventh photodetector 3a is disposed near the connection between the second laser oscillator 3 and the second optical fiber 5. Furthermore, the seventh photodetector 3a is positioned to receive the reflected light from the second laser B transmitted through the second optical fiber 5.

[0217] According to this embodiment, when the first laser A and the second laser B are irradiated onto the workpiece W using the first to fourth photodetectors 91b, 92a, 91a, 92b, the sixth photodetector 2a, and the seventh photodetector 3a, it is possible to determine whether there is an abnormality in the processing state of the workpiece W. Furthermore, the power of the first laser A and the second laser B irradiating the workpiece W can be inferred. It is also possible to determine whether there is an abnormality in the optical components inside the housing 11, such as the protective glass 14. Figure 12 Let's explain this further. Additionally, for ease of explanation, Figure 12 This example only illustrates the case where the first laser A is directed at the workpiece W.

[0218] Figure 12 Cases 1 and 2 in the middle Figure 10 Cases 1 and 2 are the same. Figure 12 Situations 5 and 6 in the middle Figure 10 Cases 3 and 4 are the same. Therefore, detailed explanations for these are omitted. Additionally, in... Figure 12 In cases 1 and 2, the output signal P6 of the sixth photodetector 2a is 0W. This is because no reflected light from the workpiece W is generated, or the reflected light from the workpiece W is very weak. On the other hand, in Figure 12 In cases 5 and 6, the output signal P6 of the sixth photodetector 2a is set to be the same as the output signal P3 of the third photodetector 91a.

[0219] The 6th photodetector 2a mainly targets... Figure 7 The returned light component A0 is received and output as output signal P6. It is assumed that the returned light component A0, like the returned light component A1, is approximately proportional to the power of the first laser A irradiating the workpiece W.

[0220] on the other hand, Figure 12 Cases 3 and 4 are cases where, in addition to the reflected light from the workpiece W, a halo effect is also generated on the surface of the protective glass 14.

[0221] In this case, as described above, the output signal P3 of the third photodetector 91a contains a vignetting component A2. On the other hand, the vignetting component A2 is generated by the reflection of the first laser A due to the unevenness created on the surface of the protective glass 14, etc., caused by sputtering material or dust adhering to it. This unevenness often has a size similar to the wavelength of the first laser A, thus increasing the scattering angle of the first laser A. Therefore, the vignetting component A2 is almost never incident on the first optical fiber 4 and detected by the sixth photodetector 2a. In view of this, when the output signal P3 of the third photodetector 91a is larger than the output signal P6 of the sixth photodetector 2a, it can be determined that the output signal P3 contains the vignetting component A2.

[0222] In case 3, the value of output signal P3 is the same as that in case 5 (=15W), while output signal P6 is 0W. In this case, based on the pre-calculated ratio or difference between the returned light component A1 and the vignetting component A2, the contribution of the reflected light from the protective glass 14 is estimated to be around 1W.

[0223] In case 3, the output signal P6 is also 0W. Based on the pre-calculated ratio or difference between the returned light component A1 and the vignetting component A2, the contribution of the reflected light from the protective glass 14 is estimated to be around 1W.

[0224] Based on the above, by comparing the output signal P3 of the third photodetector 91a with the output signal P6 of the sixth photodetector 2a, it is possible to infer the power of the amount of light halos on the surface of the optical components such as the protective glass 14 in the first laser A.

[0225] Furthermore, it can be clearly understood that when the second laser B is irradiated onto the workpiece W, by comparing the output signal P4 of the fourth photodetector 92b with the output signal P7 of the seventh photodetector 3a, the power of the second laser B that is gradually reflected on the surface of the optical components such as the protective glass 14 can be inferred.

[0226] Furthermore, when the first laser A and the second laser B are simultaneously irradiated onto the workpiece W, the power of the amount of halos on the surface of the optical components such as the protective glass 14 in the first laser A can be inferred by comparing the output signal P3 of the third photodetector 91a with the output signal P6 of the sixth photodetector 2a. Simultaneously, the power of the amount of halos on the surface of the optical components such as the protective glass 14 in the second laser B can be inferred by comparing the output signal P7 of the seventh photodetector 3a with the output signal P4 of the fourth photodetector 92b.

[0227] Furthermore, according to this embodiment, it can naturally achieve the same effect as the features shown in Embodiments 1 and 2. In other words, it can be said that the anomaly detection method involved in this embodiment has the following structure.

[0228] When the second laser B is irradiated onto the workpiece W, the output signal P1 of the first photodetector 91b is used to determine whether there is an abnormality in the processing state of the workpiece W.

[0229] When the first laser A is irradiated onto the workpiece W, the output signal P2 of the second photodetector 92a is used to determine whether there is an abnormality in the processing state of the workpiece W.

[0230] Based on the output signals P2 and P3 of the second photodetector 92a and the third photodetector 91a, the output of the first laser A is inferred.

[0231] Based on the output signals P1 and P4 of the first photodetector 91b and the fourth photodetector 92b, the output of the second laser B is inferred.

[0232] Based on the output signals P3 and P6 of the third photodetector 91a and the sixth photodetector 2a, it is determined whether there is any abnormality in the optical components configured in the optical path of the first laser A.

[0233] Based on the output signals P4 and P7 of the fourth photodetector 92b and the seventh photodetector 3a, it is determined whether there is any abnormality in the optical components configured in the optical path of the second laser B.

[0234] Industrial availability

[0235] This disclosure is useful because it can be applied to laser processing heads and laser processing systems that emit lasers of different wavelengths.

Claims

1. A laser processing head comprising: a housing, and a plurality of optical components disposed within the housing, The housing is provided with the following: The first light entrance port receives the first laser beam. The second light entrance is used to receive the second laser beam. The light irradiation port emits the first laser and the second laser outwards; and Next door, the optical path of the first laser entering from the first light entrance port is separated from the optical path of the second laser entering from the second light entrance port. The wavelength of the second laser is shorter than the wavelength of the first laser. The laser processing head also features: A first photodetector is disposed around the optical path of the first laser beam incident from the first light entrance port; and A second photodetector is disposed around the optical path of the second laser light incident from the second light entrance. The first photodetector is positioned on the side sandwiched between the partition wall and opposite to the second photodetector. The first photodetector receives light in the second band, which includes the wavelength of the second laser. The second photodetector receives light in the first band containing the wavelength of the first laser. At least a portion of the plurality of optical components are disposed inside the housing to alter the optical path of at least one of the first laser and the second laser, such that the optical axis of the first laser emitted from the light irradiation port is substantially aligned with the optical axis of the second laser.

2. The laser processing head according to claim 1, wherein, The plurality of optical components include at least: A deflecting mirror is placed in the optical path of the second laser to reflect the second laser, thereby changing the optical path. A dichroic mirror is placed in the optical path of the first laser and in the optical path of the second laser reflected by the deflecting mirror; and Protective glass, covering the light irradiation port. The dichroic mirror transmits most of the first laser beam, directing it toward the light irradiation port, and The dichroic mirror reflects most of the second laser beam, directing it toward the light irradiation port.

3. The laser processing head according to claim 2, wherein, Inside the housing, A first collimating lens is disposed between the first light entrance and the dichroic mirror. A second collimating lens is disposed between the second light entrance and the deflecting mirror. A workpiece-side condenser lens is disposed between the dichroic mirror and the light irradiation port. The first collimating lens parallelizes the first laser beam and directs it onto the dichroic mirror. The second collimating lens parallelizes the second laser beam and directs it onto the deflecting mirror. The workpiece-side focusing lens focuses the incident first laser and the second laser at a predetermined focusing position.

4. The laser processing head according to claim 2 or 3, wherein, The plurality of optical components further include: An aperture is positioned within the optical path of the second laser that transmits through the dichroic mirror and within the optical path of the first laser that is reflected by the dichroic mirror; and A detection-side focusing lens is positioned in the optical path of the first laser and the second laser, which pass through the aperture. A fifth photodetector is configured inside the housing at a position that allows it to receive light from the first laser and the second laser, which are transmitted through the detection-side focusing lens. The fifth photodetector monitors the output of at least one of the first laser and the second laser.

5. The laser processing head according to claim 4, wherein, The fifth photodetector has at least the following features: Multiple first light-receiving units receive light in a wavelength band including that of the first laser; and Multiple second light-receiving units receive light in a wavelength band including that of the second laser. The plurality of first light-receiving parts and the plurality of second light-receiving parts are arranged periodically on the light-receiving surface of the fifth photodetector.

6. The laser processing head according to claim 5, wherein, The fifth photodetector is an image sensor, which consists of four pixels arranged periodically on a light-receiving surface, each capable of receiving near-infrared light or infrared light, red light, green light, and blue light respectively.

7. The laser processing head according to any one of claims 1 to 3, wherein, The first band refers to wavelengths above 900nm and below 1200nm. The second band is above 400nm and below 700nm.

8. The laser processing head according to any one of claims 1 to 3, wherein, The laser processing head also features: A third photodetector is disposed around the optical path of the first laser beam incident from the first light entrance port; and A fourth photodetector is disposed around the optical path of the second laser beam incident from the second light entrance port. The third photodetector is positioned on the side sandwiched between the partition wall and opposite to the fourth photodetector. The third photodetector receives the light from the first wavelength band. The fourth photodetector receives light from the second wavelength band.

9. A laser processing system, comprising at least: The laser processing head according to any one of claims 1 to 7; The first laser oscillator emits the first laser; The second laser oscillator emits the second laser; A first optical fiber, connected to the first optical input port, transmits the first laser emitted from the first laser oscillator to the laser processing head; and The second optical fiber, connected to the second optical input port, transmits the second laser emitted from the second laser oscillator to the laser processing head. The laser processing head irradiates the workpiece with at least one of the first laser and the second laser.

10. A laser processing system, comprising at least: The laser processing head according to claim 8; The first laser oscillator emits the first laser; The second laser oscillator emits the second laser; A first optical fiber, connected to the first optical input port, transmits the first laser emitted from the first laser oscillator to the laser processing head; and The second optical fiber, connected to the second optical input port, transmits the second laser emitted from the second laser oscillator to the laser processing head. The laser processing head irradiates the workpiece with at least one of the first laser and the second laser.

11. The laser processing system according to claim 10, wherein, A sixth photodetector is disposed near the connection point with the first optical fiber in the first laser oscillator, at a position where it can receive reflected light from the first optical fiber. In the second laser oscillator, a seventh photodetector is configured near the connection point with the second optical fiber, at a position where the reflected light from the second optical fiber can be received.

12. A method for determining anomalies in a laser processing system, which is a method for determining the presence or absence of anomalies in the laser processing system as described in claim 9. When the second laser is directed at the workpiece... Based on the output signal of the first photodetector, it is determined whether there is any abnormality in the processing state of the workpiece or the state of the optical components inside the housing. When the first laser is directed at the workpiece... Based on the output signal of the second photodetector, it is determined whether there is any abnormality in the processing state of the workpiece or the state of the optical components inside the housing.

13. A method for determining anomalies in a laser processing system, which is a method for determining the presence or absence of anomalies in the laser processing system described in claim 10. When the second laser is directed at the workpiece... Based on the output signal of the first photodetector, it is determined whether there is any abnormality in the processing state of the workpiece. When the first laser is directed at the workpiece... Based on the output signal of the second photodetector, it is determined whether there is any abnormality in the processing state of the workpiece. Based on the output signals of the second and third photodetectors, the output of the first laser is inferred. Furthermore, it is determined whether there are any abnormalities in the state of the optical components inside the housing. Based on the output signals of the first photodetector and the fourth photodetector, the output of the second laser is inferred. In addition, it is determined whether there is any abnormality in the state of the optical components inside the housing.

14. A method for determining anomalies in a laser processing system, which is a method for determining the presence or absence of anomalies in the laser processing system described in claim 11. When the second laser is directed at the workpiece... Based on the output signal of the first photodetector, it is determined whether there is any abnormality in the processing state of the workpiece. When the first laser is directed at the workpiece... Based on the output signal of the second photodetector, it is determined whether there is any abnormality in the processing state of the workpiece. Based on the output signals of the second and third photodetectors, the output of the first laser is inferred. Based on the output signals of the first photodetector and the fourth photodetector, the output of the second laser is inferred. Based on the output signals of the third and sixth photodetectors, it is determined whether there is any abnormality in the optical components configured in the optical path of the first laser. Based on the output signals of the fourth and seventh photodetectors, it is determined whether there is any abnormality in the optical components configured in the optical path of the second laser.

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