Laser machining head

Abstract

A laser processing head (10) has a housing (11) and a plurality of optical components. The housing (11) is provided with: first and second light incident ports (12a), (12b) for respectively incident first and second lasers (A), (B); and a light irradiation port (13). The second laser (B) has a different wavelength from the first laser (A). The plurality of optical components include a bending mirror (30), a dichroic mirror (40), an aperture (71), and a detection-side condenser lens (70). The first and second lasers (A), (B) transmitted through the detection-side condenser lens (70) are received by an image sensor (60). The aperture (71) is configured to reduce the diameters of the first and second lasers (A), (B) incident to the detection-side condenser lens (70).

Description

[0001] This application is a divisional application of application number "2022800260868", filed on March 17, 2022, entitled "Laser processing head and laser processing system having the laser processing head". Technical Field

[0002] This disclosure relates to laser processing heads, and more particularly to a laser processing head that emits two lasers with different wavelengths, and a laser processing system having the laser processing head. Background Technology

[0003] 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.

[0004] For example, Patent Documents 1 and 2 disclose a laser processing system in which a laser emitted from a laser oscillator is transmitted in an optical fiber and irradiated onto a workpiece via multiple optical systems. The laser emitted from the optical fiber is converted into parallel light in a collimating lens, then focused by a condenser lens and irradiated onto the surface of the workpiece. Furthermore, the collimating lens and the condenser lens are configured to be movable along the optical axis of the laser. By moving the collimating lens and the condenser lens along the optical axis, the diameter of the laser beam on the surface of the workpiece can be varied.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: JP Japanese Patent Application Publication No. 2009-226473

[0008] Patent Document 2: JP 2014-079802 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] 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 on the same optical axis using a laser processing head, focusing each laser beam separately onto the workpiece. Because hybrid laser processing systems can utilize the advantages of each laser or compensate for its shortcomings, they offer many advantages compared to existing laser processing systems that utilize only one laser.

[0011] However, in hybrid laser processing systems, the focusing position and spot diameter on the workpiece surface need to be adjusted for two lasers with different wavelengths. Therefore, compared with existing laser processing systems that use only one laser, adjusting the focusing state of the laser is more difficult.

[0012] Furthermore, in hybrid laser processing systems, the number of components that make up the system usually increases in order to process two types of lasers. In particular, laser processing heads with multiple internal optical components may become larger.

[0013] This disclosure is made in view of relevant points and its purpose is to provide a laser processing head that can be miniaturized while adjusting the focusing state for two lasers with different wavelengths, and a laser processing system having the laser processing head.

[0014] Methods for solving problems

[0015] The laser processing head disclosed herein comprises: a housing; and a plurality of optical components disposed inside the housing, wherein the housing is respectively provided with: a first light entrance for receiving a first laser; a second light entrance for receiving a second laser with a wavelength different from that of the first laser; and a light irradiation port for emitting the first laser and the second laser to the outside. The plurality of optical components include at least: a bending mirror disposed in the optical path of the second laser to reflect the second laser and change the optical path; a dichroic mirror disposed in the optical path of the first laser and reflected by the bending mirror in the optical path of the second laser; and an aperture disposed in the optical path of the second laser transmitted through the dichroic mirror and reflected by the dichroic mirror in the optical path of the first laser. In the optical path; and a detection-side condenser lens, disposed in the optical path of the first laser and the second laser passing through the aperture, a photodetector is disposed inside the housing at a position that can respectively receive the first laser and the second laser transmitted through the detection-side condenser lens, the dichroic mirror causes most of the first laser to be transmitted to the light irradiation port, and causes the remaining part of the first laser to be reflected to the aperture, and causes most of the second laser to be reflected to the light irradiation port, and causes the remaining part of the second laser to be transmitted to the aperture, the aperture being configured to reduce the diameter of the first laser and the second laser incident on the detection-side condenser lens.

[0016] The laser processing system disclosed herein comprises 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.

[0017] Invention Effects

[0018] According to this disclosure, the focusing state for two lasers with different wavelengths can be adjusted in a hybrid laser processing system. Furthermore, it enables the miniaturization of the laser processing head. Attached Figure Description

[0019] Figure 1 This is a schematic structural diagram of the laser processing system involved in the implementation method.

[0020] Figure 2 It is a schematic structural diagram showing the internal structure of a laser processing head.

[0021] Figure 3A This is a schematic diagram illustrating the change in the beam diameter of the first laser caused by the aperture.

[0022] Figure 3B This is a schematic diagram illustrating the change in the beam diameter of the second laser caused by the aperture.

[0023] Figure 4 This is a schematic diagram showing the pixel structure of an image sensor.

[0024] Figure 5 This is a graph illustrating the relationship between the light-receiving efficiency of an RGB pixel and its wavelength.

[0025] Figure 6 This is a schematic diagram illustrating the pixel structure of other image sensors.

[0026] Figure 7A This is an example of an image showing the light spots of the first and second lasers focused on the light-receiving surface of an image sensor.

[0027] Figure 7B This is an example of an image showing the spot of the first and second lasers focused on the surface of a workpiece.

[0028] Figure 8A The comparative example involves the following: Figure 7A A fairly accurate diagram.

[0029] Figure 8BThe comparative example involves the following: Figure 7B A fairly accurate diagram.

[0030] Figure 9 This is a schematic diagram showing the main parts of the internal structure of the laser processing head involved in the modified example. Detailed Implementation

[0031] The embodiments of this disclosure are described below with reference to the accompanying drawings. Furthermore, the following description of preferred embodiments is merely illustrative in nature, and this disclosure is not intended to limit its application or use.

[0032] (Implementation Method)

[0033] [Structure of a laser processing system]

[0034] 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 utilizes two lasers with different wavelengths to perform laser processing such as cutting, welding, and drilling on the workpiece W.

[0035] 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.

[0036] Laser oscillator 2 emits laser light A. Laser oscillator 3 emits laser light 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. Near-infrared light is generally used in laser processing, but blue light is also being used in recent years due to its good absorption rate in copper. Alternatively, laser B can be set to green light (wavelength: 450nm–550nm).

[0037] 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.

[0038] 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 traveling from the laser processing head 10 to the workpiece W are the same. For example, when both the first laser A and the second laser B are simultaneously irradiated onto the surface W1 of the workpiece W, the workpiece W is irradiated with the optical axes of the first laser A and the second laser B coinciding. Details regarding the laser processing head 10 will be described later.

[0039] The robotic arm 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 robotic arm 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.

[0040] [Structure of the laser processing head]

[0041] 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, and right), and Z is the vertical direction (up and 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, but changes according to the movement of each laser A and B.

[0042] The laser processing head 10 uses 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 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.

[0043] In the outer casing 11, a first light entrance 12a and a second light entrance 12b are provided on the upper side in the Z direction. The first light entrance 12a and the second light entrance 12b are provided with a given interval. The first optical fiber 4 is connected to the first light entrance 12a, and the first laser A enters the interior of the outer casing 11 through the first light entrance 12a. The second optical fiber 5 is connected to the second light entrance 12b, and the second laser B enters the interior of the outer casing 11 through the second light entrance 12b. In addition, the first light entrance 12a and the second light entrance 12b are sometimes collectively referred to as the entrance section 12.

[0044] 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 (not shown) provided in the light irradiation port 13.

[0045] The first collimating lens 20 transforms the first laser A into a parallel ray. The second collimating lens 21 transforms the second laser B into a parallel ray. Furthermore, until they are incident on the first collimating lens 20 and the second collimating lens 21 respectively, the first laser A and the second laser B travel in parallel in a straight line in the Z direction.

[0046] The bending mirror 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 changing it to a direction orthogonal to the optical axis of the first laser A (Y direction).

[0047] 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 direction, 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 direction.

[0048] A light irradiation port 13 is provided 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. 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.

[0049] Furthermore, the term "major portion" 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 term "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.

[0050] 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. The focused first laser A and the second laser B then irradiate the surface W1 of the workpiece W through the light irradiation port 13. The workpiece-side condenser lens 50 can 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 the same in the Z direction.

[0051] The image sensor (photodetector) 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 then 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 side traveling along the optical axis 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 the remaining portions of the first laser A reflected by the dichroic mirror 40 and the remaining portions of the second laser B transmitted through the dichroic mirror 40 on the light-receiving surface 61, respectively.

[0052] Aperture 71 is positioned between dichroic mirror 40 and detection-side condenser lens 70 along the optical axis. As will be described in detail later, aperture 71 is configured to reduce the diameters of the first laser A and the second laser B incident on the detection-side condenser lens 70 (hereinafter, sometimes referred to as the beam diameters of the first laser A and the second laser B, respectively).

[0053] 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 first laser A and the second laser B, respectively. Furthermore, the detection-side condenser lens 70 illuminates the light-receiving surface 61 of the image sensor 60 with the focused first laser A and second laser B. The detection-side condenser lens 70 may 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 detection-side condenser lens 70 are approximately aligned in the Y direction.

[0054] The size and curvature of the detection-side condenser lens 70 are set, and the distance between the detection-side condenser lens 70 and the image sensor 60 is set so that it corresponds to the focusing state of the first laser A irradiating the surface W1 of the workpiece W. That is, 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.

[0055] Similarly, the size and curvature of the detection-side condenser lens 70 are set, and the distance between the detection-side condenser lens 70 and the image sensor 60 is set so that it corresponds to the focusing state of the second laser B irradiating the surface W1 of the workpiece W. That is, 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.

[0056] For example, on the light-receiving surface 61 of the image sensor 60, if the spot diameter of the first laser A (the first spot diameter Daj on the detection side) increases, then the spot diameter of the first laser A irradiating the surface W1 of the workpiece W (the first spot diameter Dai on the workpiece side) also increases. Similarly, on the light-receiving surface 61 of the image sensor 60, if the focusing position of the second laser B shifts, then the focusing position of the second laser B irradiating the surface W1 of the workpiece W also shifts. 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.

[0057] The mirror-side actuator 80 changes the tilt angle of the curved mirror 30. The mirror-side actuator 80 is, for example, composed of a tilting shaft and a motor that rotates the tilting shaft. Due to the change in 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. Consequently, the focusing position of the second laser B changes.

[0058] 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. The movement of the collimating lenses 20 and 21 along the optical axis (Z direction) caused by the lens-side actuators 81 and 82 changes the spot diameters of the first laser A and the second laser B (described later).

[0059] 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 move straight in the optical axis direction (Z direction). Sometimes it moves slightly or tilts slightly in the horizontal direction (X direction and Y direction) orthogonal to the optical axis direction.

[0060] [Beam diameter change caused by aperture]

[0061] Figure 3A This diagram illustrates the change in the beam diameter of the first laser caused by the aperture. Figure 3B This diagram illustrates the change in the beam diameter of the second laser caused by the aperture.

[0062] When the maximum aperture diameter of aperture 71 is greater than the beam diameter φ1 of the first laser A and the beam diameter φ3 of the second laser B, such as Figure 3A The left side and Figure 3B As shown on the left, the first laser A and the second laser B are incident on the detection-side focusing lens 70 while maintaining their original beam diameters.

[0063] However, the outputs of the first laser A and the second laser B used in laser processing are typically hundreds of W to several kW. Therefore, even if only 1% of them are incident on the image sensor 60, the power of the laser irradiating the light-receiving surface 61 will reach several W to tens of W. In this case, the excessive output can cause halos and other disturbances in the image acquired by the image sensor 60, or, with prolonged use, the color filter and other components of the image sensor 60 may burn out. Furthermore, the size of the detection-side condenser lens 70 needs to be set so that the beam diameter φ1 or φ3 is within the effective focusing diameter of the detection-side condenser lens 70. If the beam diameter φ1 or φ3 is larger than a given value, the detection-side condenser lens 70 will become too large.

[0064] Therefore, by appropriately narrowing the aperture diameter of aperture 71, such as Figure 3A The left side and Figure 3B As shown on the left, the beam diameters of the first laser A and the second laser B are reduced to φ2 (φ2 < φ1, φ3). This allows for adjustment by reducing the diameters of the first laser A and the second laser B incident on the detection-side condenser lens 70, thereby increasing the effective focusing diameter of the condenser lens 70. In other words, it prevents the detection-side condenser lens 70 from becoming too large, and consequently, prevents the laser processing head 10 from becoming too large.

[0065] Furthermore, by narrowing the aperture diameter of the aperture 71, excess beams from the first laser A and the second laser B can be blocked and directed onto the light-receiving surface 61 of 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, thereby suppressing the aforementioned problems such as image distortion and burn-out of color filters.

[0066] [Structure of an image sensor]

[0067] Figure 4 This diagram illustrates the pixel structure of an image sensor. Figure 5 This indicates the relationship between the light-receiving efficiency of an RGB pixel and its wavelength. Figure 6 This diagram illustrates the pixel structure of other image sensors.

[0068] like Figure 4 As shown, the image sensor 60 arranges 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, it is a color filter arrangement in which the G pixels of one side are replaced with N pixels, compared to the well-known Bayer arrangement.

[0069] like Figure 5As shown, the R pixel exhibits higher quantum efficiency in photoelectric conversion of light in the 600nm–850nm wavelength range, efficiently converting typical red light (600nm–700nm range) into electrical signals. The G pixel exhibits higher quantum efficiency in photoelectric conversion of light in the 500nm–550nm wavelength range, efficiently converting typical green light (500nm–550nm range) into electrical signals. The B pixel exhibits higher quantum efficiency in photoelectric conversion of light in the 400nm–500nm wavelength range, efficiently converting typical blue light (420nm–480nm range) into electrical signals. Furthermore, although not illustrated, the N pixel exhibits higher quantum efficiency in photoelectric conversion of light in the 900nm–1200nm wavelength range, efficiently converting near-infrared or infrared light (900nm–1200nm range) into electrical signals.

[0070] As mentioned above, the wavelength of the first laser A is in the range of 900nm to 1200nm, and the wavelength of the second laser B is in the range of 400nm to 450nm. Therefore, by using... Figure 4 The image sensor 60 shown can reliably convert the first laser A and the second laser B from the transmission 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 in the light-receiving surface 61 can be determined. As described later, the focusing position and spot diameter of the first laser A and the second laser B on the surface W1 of the workpiece W can be corrected based on this two-dimensional distribution and the spot diameter of the first laser A and the second laser B in the light-receiving surface 61.

[0071] Furthermore, if we consider the viewpoint that the first laser A and the second laser B can be reliably converted into electrical signals respectively, then as... Figure 6 As shown, it is also possible to arrange only the two types of pixels, B and N, periodically. Furthermore, when the second laser B is green light, in... Figure 6 In this configuration, B pixels can be replaced with G pixels. That is, the image sensor 60 has multiple first light-receiving portions (N pixels) that receive light in a first band, such as 900nm to 1200nm, containing the wavelength of the first laser A. Furthermore, the image sensor 60 has multiple second light-receiving portions (B pixels and / or G pixels) that receive light in a second band, such as 400nm to 600nm, containing the wavelength of the second laser B. A pixel structure in which the multiple first light-receiving portions and the multiple second light-receiving portions are periodically arranged on the light-receiving surface 61 is sufficient.

[0072] [Monitoring and adjusting the focus status]

[0073] In the actual case of laser processing of workpiece W, it is impossible to monitor the focusing states of the first laser A and the second laser B on the surface W1. On the other hand, 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. That is, it is possible to monitor the focusing states of the first laser A and the second laser B 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 (e.g., referring to...). Figure 7A ( ) to monitor the focusing state of the light on the surface W1 of the workpiece W.

[0074] Furthermore, if the focusing positions of the first laser A and the second laser B deviate 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. Additionally, 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. This allows the first laser A to 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. This allows the second laser B to be focused on the surface W1 of the workpiece W.

[0075] [Effects, etc.]

[0076] 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.

[0077] The outer casing 11 is provided with a first light inlet 12a for the first laser A, a second light inlet 12b for the second laser B, and a light irradiation port 13 for the first laser A and the second laser B to be emitted to the outside. The wavelength of the second laser B is shorter than that of the first laser A.

[0078] The multiple optical components include at least: a bending mirror 30, disposed in the optical path of the second laser B, which reflects the second laser B to change the optical path; and a dichroic mirror 40, disposed in the optical path of the first laser A and in the optical path of the second laser B reflected by the bending mirror 30.

[0079] In addition, multiple optical components include: an aperture 71, which is disposed in the optical path of the second laser B in the transmission dichroic mirror 40 and in 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 that pass through the aperture 71.

[0080] An image sensor (photodetector) 60 is disposed inside the housing 11 at the positions of the first laser A and the second laser B, which can respectively receive the transmission detection side focusing lens 70.

[0081] The dichroic mirror 40 causes most of the first laser A to be transmitted to the light irradiation port 13, and causes the remaining portion of the first laser A to be reflected to the aperture 71. Furthermore, the aperture 71 causes most of the second laser B to be reflected to the light irradiation port 13, and causes the remaining portion of the second laser B to be transmitted to the aperture 71.

[0082] The aperture 71 is configured to reduce the diameters of the first laser A and the second laser B incident on the detection-side condenser lens 70, respectively.

[0083] Aperture 71 is a narrowing clamp for the first laser A and the second laser B. Typically, the thickness along the optical axis can be thin; furthermore, the diameter direction of the laser (…) Figure 2 The size of the Z-direction (in the image) only needs to be large enough for the first laser A and the second laser B to pass through. On the other hand, if the diameter of the detection-side focusing lens 70 is increased to ensure that the first laser A and the second laser B are within the effective diameter, the curvature, etc., also need to be changed. Figure 2 In the example shown, the thickness in the Y direction could potentially increase significantly.

[0084] According to this embodiment, by setting the aperture 71 to reduce the diameters of the first laser A and the second laser B incident on the detection-side condenser lens 70, the enlargement of the detection-side condenser lens 70 can be suppressed, thereby suppressing the enlargement of the laser processing head 10.

[0085] Furthermore, by narrowing the aperture diameter of the aperture 71, excess beams from the first laser A and the second laser B can be blocked and directed onto the light-receiving surface 61 of 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, thereby suppressing the aforementioned image distortion, color filter burnout, and other adverse conditions. This will be explained further.

[0086] Figure 7A This shows an example of the spot images of the first and second lasers focused on the light-receiving surface of an image sensor. Figure 7B This shows an example of the spot images of the first and second lasers focused on the surface of a workpiece. Furthermore, Figure 8A Indicates the comparison example involving the and Figure 7A Quite a picture, Figure 8B Indicates the comparison example involving the and Figure 7B A fairly accurate diagram. Additionally... Figure 8A , 8B This corresponds to the case where the aperture 71 is not set in the laser processing head 10 or the aperture 71 is not activated.

[0087] By appropriately setting the configuration relationship of the various optical components inside the laser processing head 10, such as... Figure 7B , 8B 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 dimensions suitable for processing. 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 dimensions suitable for processing.

[0088] However, without an aperture 71 on the laser processing head 10, as described above, the power of the first laser A and the second laser B incident on the light-receiving surface 61 of the image sensor 60 sometimes becomes excessive. In this case, for example... Figure 8A As shown, a halo will be generated on the captured image, and it will be difficult to clearly distinguish the first spot Saj on the detection side of the first laser A and the second spot Sbj on the detection side of the second laser A.

[0089] On the other hand, according to this embodiment, by providing an aperture 71 in the laser processing head 10, the power of the first laser A and the second laser B incident on the detection-side focusing lens 70 can be reduced, and their diameters can be appropriately narrowed. In this case, for example, as... Figure 7A As shown, the generation of halos and the like can be eliminated, and image distortion can be suppressed. Furthermore, the first spot Saj on the detection side of the first laser A and the second spot Sbj on the detection side of the second laser A can be clearly and separately identified. The diameter Daj of the first spot on the detection side of the first laser A and the diameter Dbj of the second spot on the detection side of the second laser A can be measured separately. Furthermore, defects such as burn-out of color filters, as described above, can be suppressed. Based on these, the focusing positions of the first laser A and the second laser B on the surface W1 of the workpiece W can be adjusted based on the images of the first laser A and the second laser B acquired by the image sensor 60.

[0090] Inside the housing 11, in the Z direction, a first collimating lens 20 is provided between the first light entrance 12a and the dichroic mirror 40. A second collimating lens 21 is provided between the second light entrance 12b and the curved mirror 30. A workpiece-side condensing lens 50 is provided between the dichroic mirror 40 and the light irradiation port 13.

[0091] 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 curved mirror 30. The workpiece-side focusing lens 50 focuses the incident first laser A and second laser B at given focusing positions.

[0092] According to this embodiment, by having the above structure, the optical axes of the first laser A and the second laser B, which travel from the light irradiation port 13 to the workpiece W, can be made to be substantially aligned. Furthermore, the first laser A and the second laser B can be focused onto the surface W1 of the workpiece W. Based on these features, the focusing positions of the first laser A and the second laser B on the surface W1 of the workpiece W can be made substantially aligned.

[0093] The image sensor (photodetector) 60 has at least: a plurality of first light-receiving portions that receive light in a first band containing the wavelength of a first laser A; and a plurality of second light-receiving portions that receive light in a second band containing the wavelength of a second laser B. The plurality of first light-receiving portions and the plurality of second light-receiving portions are arranged periodically on the light-receiving surface 61 of the image sensor 60.

[0094] 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 with high resolution. Therefore, the focusing positions of the first laser A and the second laser B on the surface W1 of the workpiece W can be precisely adjusted.

[0095] The image sensor 60 is preferably constructed in which 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.

[0096] 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.

[0097] 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.

[0098] 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.

[0099] The laser processing head 10 irradiates the workpiece W with at least one of the first laser A and the second laser B.

[0100] According to this embodiment, the focusing positions of the first laser A and the second laser B on 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.

[0101] The laser processing system 1 may also include a robotic arm 6 that can move and hold the laser processing head 10. This allows for easy laser processing of workpieces W with complex structures.

[0102] The laser processing system 1 is configured to adjust the focusing positions of the first laser A and the second laser B on 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. This allows the focusing positions of the first laser A and the second laser B on the surface W1 of the workpiece W to be easily set to the desired positions. Consequently, the processing accuracy and quality during laser processing can be improved.

[0103] <Variation Example>

[0104] Figure 9 The diagram illustrates the main parts of the internal structure of the laser processing head involved in this variation.

[0105] Figure 9 The laser processing head 10 shown in this modified example has a neutral density filter 72 disposed between the aperture 71 and the detection-side condenser lens 70, which is consistent with... Figure 2 The laser processing heads shown are different.

[0106] As mentioned above, the output of the first laser A and the second laser B can sometimes reach several kW. Depending on the reflectivity (transmittance) of the first laser A and the second laser B in the dichroic mirror 40, even when the aperture 71 is used to block the excess beam, the power of the first laser A and the second laser B on the light-receiving surface 61 of the image sensor 60 can still become too high.

[0107] In such a situation, through, as Figure 9 By setting the light-reducing filter 72 as shown, the power of the first laser A and the second laser B incident on the light-receiving surface 61 of the image sensor 60 can be reduced. This reduces the likelihood of damage such as burn-out of the image sensor 60. Furthermore, even with long-term use, clear images of the first spot Saj on the detection side of the first laser A and the second spot Sbj on the detection side of the second laser B can be obtained.

[0108] Furthermore, the characteristics of the neutral density filter 72 are configured such that light with the same wavelength as the first laser A and the second laser B are reduced by a given ratio. On the other hand, in most laser processing systems, the output of the first laser A is set to be larger than that of the second laser B. Therefore, the neutral density filter 72 can reduce only light with the same wavelength as the first laser A. That is, the neutral density filter 72 is configured to reduce light with at least the same wavelength as the first laser A.

[0109] In addition, such as Figure 9 As shown by the dashed line, the neutral density filter 72 can be positioned between the dichroic mirror 40 and the aperture 71.

[0110] Furthermore, in this modified example, by providing an aperture 71 between the dichroic mirror 40 and the image sensor 60, the diameters of the first laser A and the second laser B incident on the detection-side condenser lens 70 can be reduced respectively. This prevents the detection-side condenser lens 70 from becoming too large, and consequently, prevents the laser processing head 10 from becoming too large.

[0111] Industrial availability

[0112] This disclosure is useful because it can be applied to laser processing heads and laser processing systems that emit lasers with different wavelengths.

[0113] Explanation of reference numerals in the attached figures

[0114] F Laser processing direction

[0115] W workpiece

[0116] W1 surface (image plane)

[0117] A First Laser

[0118] Sai, the first light spot on the workpiece side.

[0119] Dai, the diameter of the first spot on the workpiece side.

[0120] Saj detection side first spot

[0121] Diameter of the first spot on the Daj detection side

[0122] B. Second laser

[0123] Sbi workpiece side second spot

[0124] Dbi, the diameter of the second spot on the workpiece side.

[0125] Sbj detection side second spot

[0126] Dbj detection side second spot diameter

[0127] 1. Laser processing system

[0128] 2. First laser oscillator

[0129] 3. Second laser oscillator

[0130] 4. First fiber optic cable

[0131] 5. Second fiber optic cable

[0132] 10 Laser processing heads

[0133] 20 First collimating lens

[0134] 21 Second collimating lens

[0135] 30. Curved mirror

[0136] 40 dichroic mirror

[0137] 50 Workpiece-side focusing lens

[0138] 60 Image Sensor (Light Detector)

[0139] 61 Light-receiving surface

[0140] 70 Detection-side focusing lens

[0141] 71 aperture

[0142] 72 Neutral Density Filter

[0143] 80 Mirror-side actuator (adjustment unit)

[0144] 81 First lens-side actuator (adjustment unit)

[0145] 82 Second lens side actuator (adjustment unit).

Claims

1. A laser processing head, comprising: The outer shell; and Multiple optical components are disposed inside the housing. The outer casing is respectively provided with: The first light entrance is used to receive the first laser beam. A second light entrance port, through which a second laser with a wavelength different from that of the first laser; and The light irradiation port emits the first and second laser beams to the outside to irradiate the surface of the workpiece. The plurality of optical components include at least: A curved mirror is placed in the optical path of the second laser to reflect the second laser and change the optical path. A dichroic mirror is disposed in the optical path of the first laser and in the optical path of the second laser reflected by the curved mirror; An aperture is provided in the optical path of the second laser transmitted through the dichroic mirror and in the optical path of the first laser 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 photodetector is configured inside the housing at a position that can receive the first laser and the second laser transmitted through the detection-side focusing lens, respectively. The dichroic mirror causes most of the first laser beam to be transmitted to the light irradiation port and reflects the remaining portion of the first laser beam to the aperture. Similarly, it causes most of the second laser beam to be reflected to the light irradiation port and transmits the remaining portion of the second laser beam to the aperture. The aperture is configured to reduce the diameter of the first laser and the second laser incident on the detection-side focusing lens. The spot diameters of the first laser and the second laser illuminating the light-receiving surface of the photodetector are set to correspond to the spot diameters of the first laser and the second laser illuminating the surface of the workpiece.

2. The laser processing head according to claim 1, wherein, The size and curvature of the detection-side condenser lens and the distance between the detection-side condenser lens and the photodetector are set so as to correspond to the focusing state of the first laser and the second laser irradiating the surface of the workpiece.

3. The laser processing head according to claim 1 or 2, wherein, The photodetector has at least the following features: A plurality of first light-receiving sections receive light in a first band containing the wavelength of the first laser; and Multiple second light-receiving units receive light in a second band containing the wavelength 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 photodetector.

4. The laser processing head according to claim 3, wherein, The photodetector is an image sensor having multiple pixels that respectively receive near-infrared or infrared light, red light, green light, and blue light.

5. The laser processing head according to claim 1 or 2, wherein, The laser processing also features: A neutral density filter is disposed between the dichroic mirror and the aperture, or between the aperture and the detection-side condenser lens. The light-reducing filter at least reduces light of the same wavelength as the first laser.

Images