Laser processing head and laser processing system

Abstract

A laser processing head (10) is provided with: a bending mirror that bends a second laser in a direction that intersects a first laser; a dichroic mirror that transmits most of the first laser to the workpiece (W) side and reflects most of the second laser to the workpiece side; a workpiece-side condensing lens that condenses each laser and irradiates the workpiece; an image sensor that receives a remaining portion of the first laser reflected by the dichroic mirror and a remaining portion of the second laser transmitted through the dichroic mirror; a detection-side condensing lens that condenses each laser and irradiates the image sensor; and an adjustment unit that adjusts a workpiece-side condensing state in an image plane on the workpiece side. The image sensor detects a detection-side condensing state in an image plane on the image sensor side. The workpiece-side condensing state is adjusted by the adjustment unit based on the detection-side condensing state.

Description

Technical Field

[0001] This disclosure relates to laser processing heads and laser processing systems. Background Technology

[0002] Laser processing systems perform laser processing operations 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, guided by an optical fiber, and directs it onto the workpiece. The laser processing head is equipped with a focusing optical system to concentrate the laser beam and direct it onto the workpiece.

[0003] For example, the laser processing machine (laser processing head) described in Patent Document 1 includes: a collimating lens for collimating a laser emitted from a laser oscillator via an optical fiber; and a focusing lens for focusing the collimated laser onto a workpiece. The collimating lens and the focusing lens are configured to move along the optical axis. A curved mirror is provided between the collimating lens and the focusing lens to deflect the optical axis of the laser beam, which has been corrected into a parallel beam by the collimating lens, at a right angle. By moving the collimating lens and the focusing lens along the optical axis, the focusing diameter in the focusing lens can be changed.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: JP Japanese Patent Application Publication No. 2009-226473 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] However, in recent years, hybrid laser processing systems, for example, utilizing two lasers with different wavelengths such as near-infrared and blue, have become known. These systems combine two lasers with different wavelengths onto the same optical axis using a laser processing head, focusing each laser beam onto the workpiece. Because hybrid laser processing systems can utilize the advantages of two lasers or compensate for each other's weaknesses, they offer many advantages compared to existing laser processing systems that use only one laser.

[0009] In such a hybrid laser processing system, it is necessary to detect the focusing position, spot diameter, and other focusing states of each laser irradiating the workpiece, and to fine-tune each focusing state to the desired condition. For example, the focusing position of each laser is detected to ensure that the focusing positions are consistent with each other, or deviate from each other at a given interval. Furthermore, for example, the spot diameter of each laser is detected, and the spot diameter is enlarged or reduced to a given size.

[0010] In existing hybrid laser processing systems, it is difficult to detect the focusing state of each laser beam irradiating the workpiece in real time during laser processing. Therefore, in order to adjust the focusing state, it is necessary to interrupt the laser processing at one time, which is very troublesome.

[0011] This disclosure is made in view of the relevant points and its purpose is to detect and adjust the focusing state of each laser irradiating the workpiece in real time during hybrid laser processing.

[0012] Methods for solving problems

[0013] The laser processing head disclosed herein combines a first laser and a second laser, which are different from each other, to irradiate a workpiece. The laser processing head includes: a bending mirror that bends the second laser in a direction intersecting with the first laser; a dichroic mirror that transmits most of the first laser toward the workpiece side and reflects most of the second laser toward the workpiece side; a workpiece-side focusing lens that focuses the first laser and the second laser between the dichroic mirror and the workpiece, respectively, and irradiates the workpiece; and a photodetector that receives the remaining portion of the first laser reflected by the dichroic mirror and the second laser transmitted through the dichroic mirror. The remaining portion; a detection-side focusing lens, which focuses the first laser and the second laser between the dichroic mirror and the photodetector and illuminates the photodetector; and an adjustment unit, which adjusts the focusing state of at least one of the first laser and the second laser in the image plane on the workpiece side, i.e., the workpiece-side focusing state, the photodetector detects the detection-side focusing state, which is the focusing state of at least one of the first laser and the second laser in the image plane on the photodetector side and corresponds to the workpiece-side focusing state, and the workpiece-side focusing state is adjusted by the adjustment unit based on the detection-side focusing state.

[0014] The laser processing system disclosed herein comprises: the aforementioned laser processing head; a first laser oscillator that emits the first laser; a second laser oscillator that emits the second laser; a first optical fiber that transmits the first laser from the first laser oscillator to the laser processing head; and a second optical fiber that transmits the second laser from the second laser oscillator to the laser processing head.

[0015] Invention Effects

[0016] According to this disclosure, the focusing state of each laser irradiating the workpiece can be detected and adjusted in real time during hybrid laser processing. Attached Figure Description

[0017] Figure 1 This illustration shows a laser processing system according to one embodiment of the present disclosure.

[0018] Figure 2 It is a schematic structural diagram showing the internal structure of a laser processing head, indicating that the focusing positions of the first laser and the second laser are consistent with each other.

[0019] Figure 3 Indicates in Figure 2 The focusing state of each laser in the image plane on the workpiece side is observed in the direction of arrow III.

[0020] Figure 4 It means in Figure 2 The diagram shows the focusing state of each laser in the image plane on the image sensor side, as observed in the direction of arrow IV.

[0021] Figure 5 This is a schematic diagram illustrating the internal structure of a laser processing head. Figure 2 The corresponding diagram shows the situation where the focusing positions of the first laser and the second laser are offset from each other.

[0022] Figure 6 It means in Figure 5 The focusing state of each laser beam in the image plane on the workpiece side observed in the direction of arrow VI is compared with... Figure 3 A fairly accurate diagram.

[0023] Figure 7 It means in Figure 2 The focusing state of each laser in the image plane on the image sensor side is observed in the direction of arrow VII. Figure 4 A fairly accurate diagram.

[0024] Figure 8 This is a schematic diagram illustrating the internal structure of a laser processing head. Figure 2 The corresponding diagram shows the situation where the second laser is defocused.

[0025] Figure 9 It means in Figure 8 The focusing state of each laser beam in the image plane on the workpiece side observed in the direction of arrow IX is compared with... Figure 3 A fairly accurate diagram.

[0026] Figure 10 It means in Figure 8 The focusing state of each laser in the image plane on the image sensor side is observed in the direction of the X arrow. Figure 4 A fairly accurate diagram. Detailed Implementation

[0027] The embodiments of this disclosure are described in detail below with reference to the accompanying drawings. The following description of preferred embodiments is merely illustrative in nature, and this disclosure is not intended to limit its application or use.

[0028] (Laser processing system)

[0029] Figure 1This 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 utilizes two lasers with different wavelengths to perform laser processing such as cutting, welding, and drilling on the workpiece W.

[0030] 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 manipulator 6 and a control device 7.

[0031] Laser oscillator 2 emits (oscillates) laser A. Laser oscillator 3 emits (oscillates) laser B. Laser A and laser B have different wavelengths. Laser A is near-infrared light with a wavelength of 900nm–1200nm. Laser B is blue light with a wavelength of 400nm–450nm. Generally, near-infrared light is used in laser processing, but due to its good absorption rate in copper, blue light is also being used in laser processing in recent years.

[0032] 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.

[0033] The laser processing head 10 combines a first laser A and a second laser B on the same optical axis, and each of the combined first laser A and second laser B irradiates the surface W1 of the workpiece W. Details regarding the laser processing head 10 will be described later.

[0034] The manipulator 6 has a laser processing head 10 mounted at its front end, which moves the laser processing head 10. The control device 7 controls the movement of the manipulator 6 and the oscillations of lasers A and B caused by 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.

[0035] (Laser processing head)

[0036] Figure 2 This shows the internal structure of the laser processing head 10. Additionally, Figure 2 In the orthogonal coordinate system, X, Y, and Z represent directions in the coordinate system. X and Y are the horizontal directions (front, back, left, right), and Z is the vertical direction (up, down). Furthermore, the direction in which the optical axes of each laser A and B (which become virtual rays representing the beams of each laser A and B) extend is called the "optical axis direction." The optical axis direction is not always fixed in the orthogonal coordinate system X, Y, Z; it changes according to the movement of each laser A and B.

[0037] The laser processing head 10 utilizes a focusing optical system located inside the housing 11 to focus the first laser A and the second laser B onto the workpiece W. The laser processing head 10 includes a first collimating lens 20, a second collimating lens 21, a bending mirror 30, a dichroic mirror 40, a workpiece-side focusing lens 50, an image sensor 60 serving as a photodetector, a detection-side focusing lens 70, an aperture 71, 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, which together form the focusing optical system.

[0038] A first laser A from the first optical fiber 4 and a second laser B from the second optical fiber 5 are incident parallel to each other in the Z direction into the incident portion 12 inside the housing 11. In the incident portion 12, the first laser A and the second laser B travel parallel to each other in a straight line in the Z direction.

[0039] The first collimating lens 20 collimates the first laser A (parallelizes it). The second collimating lens 21 collimates the second laser B (parallelizes it). Both lasers A and B become approximately parallel beams after passing through the collimating lenses 20 and 21.

[0040] The bending mirror 30 bends the optical axis of the second laser B, which is parallel to the optical axis of the first laser A, in a direction that intersects with the optical axis of the first laser A, specifically in a direction orthogonal to the optical axis of the first laser A (Y direction).

[0041] The dichroic mirror 40 is a mirror that transmits most of light within a specific wavelength range and reflects most of light within other wavelength ranges. 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 manner, and reflects most of the second laser B incident from the surface side 42 to the surface side 42 at a substantially right angle. 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 at a substantially right angle, 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 manner.

[0042] On the optical axis travel side of most of the first laser A and most of the second laser B reflected by the dichroic mirror 40, a workpiece W is disposed across the irradiation section (irradiation port) 13 of the laser processing head 10. That is, the dichroic mirror 40 transmits most of the first laser A toward the workpiece W and reflects most of the second laser B toward the workpiece W.

[0043] The majority of each laser A and B, in terms of energy, refers to 95% to 99.9% of the lasers A and B incident before the dichroic mirror 40. The remaining portion of each laser A and B, in terms of energy, refers to 0.1% to 5% of the lasers A and B incident before the dichroic mirror 40.

[0044] 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 respectively. Then, the workpiece-side condenser lens 50 irradiates the surface W1 of the workpiece W with the focused first laser A and second laser B respectively via the irradiation section 13. The workpiece-side condenser lens 50 may have a chromatic aberration correction function. The optical axis directions of each laser A and B irradiated by the workpiece-side condenser lens 50 are approximately aligned with the Z-direction.

[0045] Image sensor 60 is an imaging element that converts the brightness and darkness of light imaged on its light-receiving surface 61 into electrical charge, reads it out, and converts it into an electrical signal. Image sensor 60 is disposed on the back side 41 of dichroic mirror 40. Specifically, image sensor 60 is disposed on the side of the optical axis travel direction of the remaining portion of the first laser A reflected by dichroic mirror 40 and the remaining portion of the second laser B transmitted through dichroic mirror 40. That is, image sensor 60 receives the remaining portion of the first laser A reflected by dichroic mirror 40 and the remaining portion of the second laser B transmitted through dichroic mirror 40 on light-receiving surface 61, respectively.

[0046] A detection-side condenser lens 70 and an aperture 71 are positioned between the dichroic mirror 40 and the image sensor 60 along the optical axis. The detection-side condenser lens 70 is located closer to the image sensor 60 than the aperture 71 along the optical axis. The detection-side condenser lens 70 focuses the first laser A and the second laser B respectively. Then, the detection-side condenser lens 70 illuminates the focused first laser A and second laser B onto the light-receiving surface 61 of the image sensor 60. The detection-side condenser lens 70 may have a chromatic aberration correction function. The aperture 71 blocks excess beams from each laser A and B, reducing the pupil diameter. The optical axis direction of each laser A and B illuminated by the detection-side condenser lens 70 is approximately aligned with the Y-direction.

[0047] The mirror-side actuator 80 changes the tilt angle of the curved mirror 30. The mirror-side actuator 80 is, for example, composed of an electric motor, a piezoelectric element, etc. Due to the change in the tilt angle of the curved mirror 30 caused by the mirror-side actuator 80, the orientation of the optical axis of the second laser B, which is bent by the curved mirror 30, changes. As a result, the focusing position of the second laser B, which will be described later, changes.

[0048] 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, composed of an electric motor, a piezoelectric element, etc. 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, composed of an electric motor, a piezoelectric element, etc. The movement of each collimating lens 20, 21 along the optical axis (Z direction) caused by each lens-side actuator 81, 82 changes the spot diameter of each laser A, B (described later).

[0049] 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 does not necessarily have to move straight in the optical axis direction (Z direction). Sometimes it may move slightly or tilt slightly in the horizontal direction (X direction and Y direction) orthogonal to the optical axis direction.

[0050] (Focusing state of each laser)

[0051] The laser processing head 10 according to this embodiment is characterized in that it can indirectly detect the focusing state of the first laser A and the second laser B in the image plane on the workpiece W side by means of an image sensor 60. In addition, the term "focusing state" is a state that encompasses various focusing methods such as focusing position, spot diameter, and blur amount.

[0052] The following is for reference. Figures 2-4 This is to illustrate the focusing state of each laser A and B. Figure 3 The focusing state Si represents the focusing state of the first laser A and the second laser B in the image plane on the W side of the workpiece, i.e., the focusing state Si on the workpiece side. Figure 4 The focusing state Sj represents the focusing state of the first laser A and the second laser B in the image plane on the image sensor 60 side, i.e., the focusing state on the detection side. The "image plane on the workpiece W side" refers to the surface (X, Y plane) on the workpiece W side that is orthogonal to the optical axis (Z direction), for example, surface W1 of the workpiece W. The "image plane on the image sensor 60 side" refers to the surface on the image sensor 60 side that is orthogonal to the optical axis, for example, the light-receiving surface 61 of the image sensor 60. Figure 3 , 4 The intensity of the color in the image represents the amount of energy of each laser A and B, and has nothing to do with the color (wavelength) of each laser A and B.

[0053] First, refer to Figure 2 , 3 To illustrate the workpiece-side focusing state Si, for example, the workpiece W can be removed and replaced with an image sensor. By directly detecting each laser A and B using this image sensor, the actual workpiece-side focusing state Si can be confirmed.

[0054] The workpiece-side focusing state Si includes: the focusing position of the first laser A in the surface W1 (image plane of the workpiece W side), i.e., the first focusing position Pai on the workpiece side; and the focusing position of the second laser B in the surface W1 (image plane of the workpiece W side), i.e., the second focusing position Pbi on the workpiece side.

[0055] Furthermore, the workpiece-side focusing state Si includes: the spot diameter of the first laser A in the surface W1 (image plane of the workpiece W), i.e., the workpiece-side first spot diameter Dai; and the spot diameter of the second laser B in the surface W1 (image plane of the workpiece W), i.e., the workpiece-side second spot diameter Dbi. Additionally, in this embodiment, "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.

[0056] Next, refer to Figure 2 , 4 To illustrate the detection-side focusing state Sj, the image sensor 60 is used to detect the detection-side focusing state Sj.

[0057] The detection-side focusing state Sj includes: the focusing position of the first laser A in the light-receiving surface 61 (image plane on the image sensor 60 side), i.e., the detection-side first focusing position Paj; and the focusing position of the second laser B in the light-receiving surface 61 (image plane on the image sensor 60 side), i.e., the detection-side second focusing position Pbj.

[0058] Furthermore, the detection-side focusing state Sj includes: the spot diameter of the first laser A in the light-receiving surface 61 (image plane on the image sensor 60 side), i.e., the detection-side first spot diameter Daj; and the spot diameter of the second laser B in the light-receiving surface 61 (image plane on the image sensor 60 side), i.e., the detection-side second spot diameter Dbj.

[0059] like Figures 2-4As shown, the focusing state Sj on the detection side corresponds to the focusing state Si on the workpiece side. Specifically, the first focusing position Paj on the detection side corresponds to the first focusing position Pai on the workpiece side. The second focusing position Pbj on the detection side corresponds to the second focusing position Pbi on the workpiece side. The first spot diameter Daj on the detection side corresponds to the first spot diameter Dai on the workpiece side. The second spot diameter Dbj on the detection side corresponds to the second spot diameter Dbi on the workpiece side. For example, if the first focusing position Pai on the workpiece side moves, the first focusing position Paj on the detection side also moves accordingly. If the second focusing position Pbi on the workpiece side moves, the second focusing position Pbj on the detection side also moves accordingly. If the first spot diameter Dai on the workpiece side expands or shrinks, the first spot diameter Daj on the detection side also expands or shrinks accordingly. If the second spot diameter Dbi on the workpiece side expands or shrinks, the second spot diameter Dbj on the detection side also expands or shrinks accordingly.

[0060] By using image sensor 60 to detect the focusing state Sj on the detection side, the focusing state Si on the workpiece side can be indirectly detected in real time (simultaneously).

[0061] (Adjustment of focusing state)

[0062] The workpiece-side focusing state Si is adjusted by the adjustment unit (mirror-side actuator 80, first lens-side actuator 81, second lens-side actuator 82) based on the detection-side focusing state Sj.

[0063] (Adjustment of the spotlight position)

[0064] First, the method for adjusting the focusing position of each laser A and B will be explained. Figures 2-4 This indicates the case where the focusing position of the first laser A and the focusing position of the second laser B are the same. That is, as shown... Figure 2 , 3 As shown, the first focusing position Pai and the second focusing position Pbi on the workpiece side are aligned in the horizontal direction (X, Y direction). Correspondingly, as... Figure 2 , 4 As shown, the first focusing position Paj on the detection side and the second focusing position Pbj on the detection side are consistent with each other.

[0065] Figures 5-7 This indicates the situation where the focusing positions of the first laser A and the second laser B are offset from each other. Specifically, the first focusing position Pai and the second focusing position Pbi on the workpiece side are offset from each other in the Y direction (horizontal direction). Correspondingly, the first focusing position Paj and the second focusing position Pbj on the detection side are offset from each other.

[0066] like Figure 2 , 5As shown, by using the mirror-side actuator 80 to change the tilt of the curved mirror 30, the second focusing position Pbi on the workpiece side and the second focusing position Pbj on the detection side are moved in a corresponding manner. That is, the second focusing position Pbj on the detection side also moves by the same amount as the second focusing position Pbi on the workpiece side.

[0067] By adjusting the tilt of the bending mirror 30 using the mirror-side actuator 80 based on the positional relationship (e.g., differential Hj) between the first focusing position Pai and the second focusing position Pbi on the workpiece side, the positional relationship (e.g., differential Hi) between the first focusing position Pai and the second focusing position Pbi on the workpiece side is adjusted.

[0068] For example, in a state where it is desired that the second focusing position Pbi on the workpiece side is not consistent with the first focusing position Pai on the workpiece side (refer to...). Figure 5 , 6 When the second focusing position Pbi on the workpiece side is consistent with the first focusing position Pai on the workpiece side (refer to...) Figure 2 , 3 Based on the difference Hj between the first focusing position Paj on the detection side and the second focusing position Pbj on the detection side (reference) Figure 5 , 7 This feedback is sent to the tilt angle of the curved mirror 30. That is, while observing the difference Hj in the image sensor 60, the tilt angle of the curved mirror 30 is changed using the mirror-side actuator 80, so that the second focusing position Pbj on the detection side coincides with the first focusing position Paj on the detection side, thereby making the difference Hj zero (see reference). Figure 2 , 4 Therefore, the second focusing position Pbi on the workpiece side is adjusted to be consistent with the first focusing position Pai on the workpiece side (the difference Hi between the first focusing position Pai on the workpiece side and the second focusing position Pbi on the workpiece side becomes zero) (Reference) Figure 2 , 3 ).

[0069] Similarly, in the desired state where the first focusing position Pai on the workpiece side and the second focusing position Pbi on the workpiece side are aligned (refer to...) Figure 2 , 3 In the case of forcibly and actively setting the difference Hi between the first focusing position Pai on the workpiece side and the second focusing position Pbi on the workpiece side (refer to...) Figure 5 , 6 The tilt angle of the curved mirror 30 is also fed back based on the difference Hj between the first focusing position Paj and the second focusing position Pbj on the detection side. That is, while observing the difference Hj in the image sensor 60, the tilt angle of the curved mirror 30 is changed using the mirror-side actuator 80, causing the second focusing position Pbj on the detection side to move relative to the first focusing position Paj on the detection side, so that the difference Hj becomes a given value (see reference). Figure 5 , 7 Therefore, the difference Hi between the first focusing position Pai on the workpiece side and the second focusing position Pbi on the workpiece side is adjusted to a given value (refer to...). Figure 5 , 6 ).

[0070] Furthermore, such as Figure 5 , 6 As shown, the second focusing position Pbi on the workpiece side can also be adjusted to be located on the front side (traveling side) of the laser processing direction F (the direction of movement of the laser processing head 10 relative to the workpiece W) which is closer to the first focusing position Pai on the workpiece side than the first focusing position Pai on the workpiece side.

[0071] (Adjustment of light spot diameter)

[0072] Next, we will explain how to adjust the spot diameter of each laser A and B. Figures 2-4 This indicates a situation where neither the first laser A nor the second laser B is out of focus (deviation from the image plane along the optical axis of the focusing position). In this case, as... Figure 2 , 3 As shown, the second focusing position Pbi on the workpiece side is located on surface W1 of workpiece W in the optical axis direction. Correspondingly, as Figure 2 , 4 As shown, the second focusing position Pbi on the detection side is located on the light-receiving surface 61 of the image sensor 60 in the optical axis direction. In this case, as... Figure 2 , 3 As shown, both the diameter of the first spot (Dai) on the workpiece side and the diameter of the second spot (Dbi) on the workpiece side are small. Correspondingly, as... Figure 2 , 4 As shown, the diameters of the first spot (Daj) and the second spot (Dbj) on the detection side are both small.

[0073] Figures 8-10 This indicates the case where the second laser B is defocused. In this case, as... Figure 8 , 9 As shown, the second focusing position Pbi on the workpiece side deviates from the surface W1 of the workpiece W in the optical axis direction and is closer to the workpiece-side focusing lens 50. Correspondingly, as Figure 8 , 10 As shown, the second focusing position Pbi on the detection side deviates from the light-receiving surface 61 of the image sensor 60 in the optical axis direction and is closer to the focusing lens 70 on the detection side. Furthermore, as... Figure 8 , 9 As shown, the diameter Dbi of the second spot on the workpiece side increases. Correspondingly, as... Figure 8 , 10 As shown, the diameter Dbj of the second spot on the detection side increases.

[0074] like Figure 2 , 8 As shown, by using the second lens-side actuator 82 to move the second collimating lens 21 in the optical axis direction (Z direction), the diameters of the second light spot Dbi on the workpiece side and the second light spot Dbj on the detection side are correspondingly enlarged and reduced. That is, if the diameter of the second light spot Dbi on the workpiece side increases, the diameter of the second light spot Dbj on the detection side also increases. If the diameter of the second light spot Dbi on the workpiece side decreases, the diameter of the second light spot Dbj on the detection side also decreases.

[0075] The second spot diameter Pai on the workpiece side is adjusted by moving the second collimating lens 21 in the optical axis direction (Z direction) using the second lens-side actuator 82 based on the second spot diameter Dbj on the detection side.

[0076] For example, in a state where it is desired to defocus from the second laser B (reference) Figures 8-10 The transition to the undefocused state of the second laser B (reference) Figures 2-4 In the case of the second spot diameter Dbj on the detection side, the position of the second collimating lens 21 in the optical axis direction (Z direction) is fed back. That is, while observing the second spot diameter Dbj on the detection side in the image sensor 60 (refer to...), Figure 8 , 10 The second collimating lens 21 is moved in the optical axis direction (Z direction) using the second lens-side actuator 82 (see reference). Figure 2 , 8 To reduce the diameter Dbj of the second spot on the detection side (reference). Figure 2 , 4 As a result, the defocusing state of the second laser B is corrected, and the diameter Dbi of the second spot on the workpiece side decreases (reference). Figure 2 , 3 ).

[0077] Although not illustrated, by using the first lens-side actuator 81 to move the first collimating lens 20 in the optical axis direction (Z direction), the diameters of the first spot on the workpiece side (Dai) and the first spot on the detection side (Daj) are correspondingly enlarged and reduced. Furthermore, by using the first lens-side actuator 81 to move the first collimating lens 20 in the optical axis direction (Z direction) based on the first spot diameter on the detection side (Daj), the diameter of the first spot on the workpiece side (Dai) is adjusted.

[0078] (Effects of this implementation method)

[0079] According to this embodiment, the image sensor 60 receives 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. Therefore, the image sensor 60 can detect the detection-side focusing state Sj corresponding to the workpiece-side focusing state Si. That is, the image sensor 60 can indirectly detect the workpiece-side focusing state Si in real time by detecting the detection-side focusing state Sj.

[0080] Furthermore, based on the focusing state Sj on the detection side, the focusing state Si on the workpiece side can be adjusted in real time using the adjustment unit (mirror-side actuator 80, first lens-side actuator 81, and second lens-side actuator 82).

[0081] As described above, the focusing state Si of each laser A and B irradiating the workpiece W can be detected and adjusted in real time during hybrid laser processing.

[0082] Specifically, the image sensor 60 can indirectly detect the first focusing position Pai and the second focusing position Pbi on the workpiece side in real time by detecting the first focusing position Paj on the detection side and the second focusing position Pbj on the detection side.

[0083] Furthermore, by changing the tilt of the curved mirror 30 using the mirror-side actuator 80 based on the second focusing position Pbj on the detection side, the second focusing position Pbi on the workpiece side can be moved. Thus, the positional relationship (differential Hi) between the first focusing position Pai and the second focusing position Pbi on the workpiece side can be adjusted in real time based on the positional relationship (differential Hj) between the first focusing position Paj and the second focusing position Pbj on the detection side.

[0084] For example, it can offset the positions of the first focusing position Pai on the workpiece side from the second focusing position Pbi on the workpiece side (Hi > 0, reference). Figure 5 , 6 Correct the first focusing position Pai on the workpiece side and the second focusing position Pbi on the workpiece side to be consistent with each other (Hi = 0, reference). Figure 3 This allows the first laser A and the second laser B to be aligned on the same optical axis.

[0085] In particular, when the collimating lenses 20 and 21 are moved in the optical axis direction (Z direction), they may sometimes unexpectedly shift or tilt in the horizontal directions (X and Y directions) orthogonal to the optical axis direction. In this case, the first focusing position Pai on the workpiece side and the second focusing position Pbi on the workpiece side may sometimes unexpectedly deviate from each other. The laser processing head 10 according to this embodiment is very effective in correcting such unexpected positional deviations.

[0086] In addition, such as Figure 5 , 6As shown, the difference Hi (>0) between the first focusing position Pai and the second focusing position Pbi on the workpiece side is deliberately set, and the second focusing position Pbi on the workpiece side is further deliberately positioned to be more forward of the laser processing direction F than the first focusing position Pai on the workpiece side. Therefore, when the workpiece W is, for example, copper, the second laser B, composed of blue light with a high absorption rate for copper, can irradiate the workpiece W earlier than the first laser A, composed of near-infrared light. That is, preheating based on blue light (preparatory heating) can be performed.

[0087] The image sensor 60 can indirectly detect the workpiece-side first spot diameter Dai in real time by detecting the first spot diameter Dai on the detection side. Furthermore, by moving the first collimating lens 20 in the optical axis direction (Z direction) using the first lens-side actuator 81 based on the first spot diameter Dai on the detection side, the workpiece-side first spot diameter Dai can be enlarged or reduced. Therefore, the workpiece-side first spot diameter Dai can be adjusted in real time based on the first spot diameter Dai on the detection side. By adjusting the workpiece-side first spot diameter Dai to be smaller, the defocusing of the first laser A can be corrected.

[0088] Similarly, the image sensor 60 can indirectly detect the workpiece-side second spot diameter Dbi in real time by detecting the detection-side second spot diameter Dbj. Then, based on the detection-side second spot diameter Dbj, the second collimating lens 21 is moved in the optical axis direction (Z direction) by the second lens-side actuator 82, thereby enlarging or shrinking the workpiece-side second spot diameter Dbi. Thus, the workpiece-side second spot diameter Dbi can be adjusted in real time based on the detection-side second spot diameter Dbi. By adjusting the workpiece-side second spot diameter Dbi to be smaller, the defocusing of the second laser B can be corrected.

[0089] (Other implementation methods)

[0090] The present invention has been described above through suitable embodiments, but such description is not limiting and various changes can be made.

[0091] Regarding the case of defocusing of the second laser B, an example is given where the second focusing position Pbi on the workpiece side deviates from the surface W1 of the workpiece W in the optical axis direction and moves closer to the workpiece-side focusing lens 50 (see reference). Figures 8-10 However, this is not the only possibility. Alternatively, the second focusing position Pbi on the workpiece side may deviate from the surface W1 of the workpiece W in the optical axis direction, and move closer to the side away from the workpiece-side focusing lens 50 (the inner side of the workpiece W). In this case, the second focusing position Pbj on the detection side deviates from the light-receiving surface 61 of the image sensor 60 in the optical axis direction, and moves closer to the side away from the detection-side focusing lens 70 (the inner side of the image sensor 60). The same applies to the first laser A.

[0092] The focusing state Si on the workpiece side and the focusing state Sj on the detection side can include the ambiguity of each laser A and B.

[0093] As an adjustment unit, it may also include an actuator for adjusting the tilt of the dichroic mirror 40.

[0094] The workpiece-side focusing state Si does not need to include the focusing states of both the first laser A and the second laser B in the image plane on the workpiece W side; it only needs to include the focusing state of at least one of the first laser A and the second laser B (e.g., the spot diameter). Correspondingly, the detection-side focusing state Sj does not need to include the focusing states of both the first laser A and the second laser B in the image plane on the image sensor 60 side; it only needs to include the focusing state of at least one of the first laser A and the second laser B (e.g., the spot diameter).

[0095] In this embodiment, the first laser A is set to near-infrared light and the second laser B is set to blue light, but this is not a limitation. From the viewpoint of copper absorption rate, the second laser B may also be set to green light (wavelength: around 450nm to 550nm) instead of blue light. Alternatively, the first laser A may be set to blue or green light, and the second laser B to near-infrared light. Furthermore, light other than blue, green, or near-infrared light may also be used. The first laser A and the second laser B may also have the same wavelength.

[0096] Industrial availability

[0097] This disclosure is extremely useful and has high industrial applicability because it can be applied to laser processing heads and laser processing systems.

[0098] Explanation of reference numerals in the attached figures

[0099] F Laser processing direction

[0100] W workpiece

[0101] W1 surface (image plane)

[0102] Si workpiece side focusing state

[0103] Sj detection side focusing status

[0104] A First Laser

[0105] Pai, first focusing position on the workpiece side

[0106] Dai, the diameter of the first spot on the workpiece side.

[0107] Paj detection side first focusing position

[0108] Diameter of the first spot on the Dai detection side

[0109] B. Second laser

[0110] Pbi workpiece side second focusing position

[0111] Dbi workpiece side second spot diameter

[0112] Pbj detection side second focusing position

[0113] Dbj detection side second spot diameter

[0114] Hi, difference (positional relationship)

[0115] Hj Difference (Positional Relationship)

[0116] 1. Laser processing system

[0117] 2. First laser oscillator

[0118] 3. Second laser oscillator

[0119] 4. First fiber

[0120] 5. Second fiber optic cable

[0121] 10 Laser processing heads

[0122] 20 First collimating lens

[0123] 21 Second collimating lens

[0124] 30. Curved mirror

[0125] 40 dichroic mirror

[0126] 50 Workpiece-side focusing lens

[0127] 60 Image Sensor (Light Detector)

[0128] 61 Light-receiving surface

[0129] 70 Detection-side focusing lens

[0130] 80 Mirror-side actuator (adjustment unit)

[0131] 81. First lens-side actuator (adjustment unit)

[0132] 82 Second lens side actuator (adjustment unit).

Claims

1. A laser processing head that combines a first laser and a second laser, which are different from each other, to irradiate a workpiece, the laser processing head comprising: A bending mirror bends the second laser beam in a direction that intersects with the first laser beam; A dichroic mirror causes most of the first laser beam to be transmitted toward the workpiece side and most of the second laser beam to be reflected toward the workpiece side. A workpiece-side focusing lens focuses the first laser and the second laser between the dichroic mirror and the workpiece and directs them toward the workpiece. A photodetector receives the remaining portion of the first laser reflected by the dichroic mirror and the remaining portion of the second laser transmitted through the dichroic mirror, respectively. A detection-side focusing lens focuses the first laser and the second laser respectively between the dichroic mirror and the photodetector and illuminates the photodetector; and The adjustment unit adjusts the focusing state of at least one of the first laser and the second laser in the image plane on the workpiece side, i.e., the focusing state on the workpiece side. The photodetector detects the focusing state of at least one of the first laser and the second laser in the image plane on the photodetector side, and the detection-side focusing state corresponds to the focusing state on the workpiece side. The focusing state on the workpiece side is adjusted by the adjustment unit based on the focusing state on the detection side. The laser processing head includes: The first collimating lens collimates the first laser beam. The workpiece-side focusing state includes: The diameter of the first laser spot in the image plane on the workpiece side is the diameter of the first laser spot on the workpiece side. The detection-side focusing state includes: The detection-side first spot diameter, which is the spot diameter of the first laser in the image plane on the photodetector side and corresponds to the first spot diameter on the workpiece side. The adjustment unit includes: The first lens-side actuator moves the first collimating lens along the optical axis, thereby causing the diameter of the first light spot on the workpiece side and the diameter of the first light spot on the detection side to correspondingly increase or decrease. The diameter of the first spot on the workpiece side is adjusted by the actuator on the first lens side based on the diameter of the first spot on the detection side.

2. The laser processing head according to claim 1, wherein, The laser processing head includes: The second collimating lens collimates the second laser beam. The workpiece-side focusing state includes: The diameter of the second laser spot in the image plane on the workpiece side is the diameter of the second laser spot on the workpiece side. The detection-side focusing state includes: The detection-side second spot diameter, which is the spot diameter of the second laser in the image plane on the photodetector side and corresponds to the second spot diameter on the workpiece side. The adjustment unit includes: The second lens-side actuator moves the second collimating lens along the optical axis, causing the diameters of the second light spot on the workpiece side and the second light spot on the detection side to correspondingly increase and decrease. The diameter of the second spot on the workpiece side is adjusted by the actuator on the second lens side based on the diameter of the second spot on the detection side.

3. A laser processing head that combines a first laser and a second laser, which are different from each other, to irradiate a workpiece, the laser processing head comprising: A bending mirror bends the second laser beam in a direction that intersects with the first laser beam; A dichroic mirror causes most of the first laser beam to be transmitted toward the workpiece side and most of the second laser beam to be reflected toward the workpiece side. A workpiece-side focusing lens focuses the first laser and the second laser between the dichroic mirror and the workpiece and directs them toward the workpiece. A photodetector receives the remaining portion of the first laser reflected by the dichroic mirror and the remaining portion of the second laser transmitted through the dichroic mirror, respectively. A detection-side focusing lens focuses the first laser and the second laser respectively between the dichroic mirror and the photodetector and illuminates the photodetector; and The adjustment unit adjusts the focusing state of at least one of the first laser and the second laser in the image plane on the workpiece side, i.e., the focusing state on the workpiece side. The photodetector detects the focusing state of at least one of the first laser and the second laser in the image plane on the photodetector side, and the detection-side focusing state corresponds to the focusing state on the workpiece side. The focusing state on the workpiece side is adjusted by the adjustment unit based on the focusing state on the detection side. The laser processing head includes: The second collimating lens collimates the second laser beam. The workpiece-side focusing state includes: The diameter of the second laser spot in the image plane on the workpiece side is the diameter of the second laser spot on the workpiece side. The detection-side focusing state includes: The detection-side second spot diameter, which is the spot diameter of the second laser in the image plane on the photodetector side and corresponds to the second spot diameter on the workpiece side. The adjustment unit includes: The second lens-side actuator moves the second collimating lens along the optical axis, causing the diameters of the second light spot on the workpiece side and the second light spot on the detection side to correspondingly increase and decrease. The diameter of the second spot on the workpiece side is adjusted by the actuator on the second lens side based on the diameter of the second spot on the detection side.

4. The laser processing head according to any one of claims 1 to 3, wherein, The workpiece-side focusing state includes: The focusing position of the first laser in the image plane on the workpiece side is the first focusing position on the workpiece side; and The focusing position of the second laser in the image plane on the workpiece side is the second focusing position on the workpiece side. The detection-side focusing state includes: The first focusing position of the first laser in the image plane on the photodetector side, and the first focusing position on the detection side corresponding to the first focusing position on the workpiece side; and The detection-side second focusing position is the focusing position of the second laser in the image plane on the photodetector side and corresponds to the second focusing position on the workpiece side. The adjustment unit includes: The mirror-side actuator, by changing the tilt angle of the curved mirror, causes the second focusing position on the workpiece side and the second focusing position on the detection side to move correspondingly to each other. The positional relationship between the first focusing position on the workpiece side and the second focusing position on the workpiece side is adjusted by the mirror-side actuator based on the positional relationship between the first focusing position on the detection side and the second focusing position on the detection side.

5. The laser processing head according to claim 4, wherein, Adjust the second focusing position on the workpiece side to be consistent with the first focusing position on the workpiece side.

6. The laser processing head according to claim 4, wherein, The first laser is near-infrared light. The second laser is blue or green light. The second focusing position on the workpiece side is adjusted to be located further forward in the laser processing direction than the first focusing position on the workpiece side.

7. A laser processing system, comprising: The laser processing head according to any one of claims 1 to 6; The first laser oscillator emits the first laser; The second laser oscillator emits the second laser; A first optical fiber transmits the first laser beam from the first laser oscillator to the laser processing head; and The second optical fiber transmits the second laser from the second laser oscillator to the laser processing head.

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