Laser machining device and working distance measurement method of laser head

Abstract

To more easily and highly accurately measure a working distance of a laser beam emitted to workpiece from a laser head.SOLUTION: A laser head stores at least a first beam splitter for branching incident light which is laser light from a laser oscillator and reflection light reflected on workpiece by irradiation with the incident light, a first sensor for receiving first light which is light obtained by branching the incident light by the first beam splitter, and a second sensor for receiving second light which is light obtained by branching the reflection light by the first beam splitter. A control part measures a working distance between the laser head and the workpiece, on the basis of a difference between a light-receiving timing of the first light in the first sensor and a light-receiving timing of the second light in the second sensor.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a laser processing apparatus and a method for measuring a working distance of a laser head. [Background technology]

[0002] Patent Document 1 discloses an apparatus for measuring the depth of a weld seam (e.g., a keyhole, which is a cavity during welding) in real time during welding or joining of workpieces using irradiation. This apparatus is based on the principle of optical coherence tomography (OCT) and measures the depth of the keyhole by utilizing the coherence properties of light with an interferometer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2018-501964 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure has been devised in consideration of the conventional circumstances, and aims to provide a laser processing apparatus and a method for measuring the working distance of a laser head that can more easily and accurately measure the working distance of laser light irradiated from a laser head toward a workpiece. [Means for solving the problem]

[0005] The present disclosure provides a laser processing apparatus comprising at least a laser oscillator that generates laser light, a laser head that irradiates the laser light toward a workpiece, and a control unit, wherein the laser head houses at least a first beam splitter that splits incident light, which is the laser light from the laser oscillator, and reflected light reflected by the workpiece by irradiating the incident light, a first sensor that receives first light, which is light branched from the incident light by the first beam splitter, and a second sensor that receives second light, which is light branched from the first beam splitter, and the control unit measures a working distance from the laser head to the workpiece based on the difference between the timing at which the first light is received by the first sensor and the timing at which the second light is received by the second sensor.

[0006] The present disclosure also provides a laser processing apparatus including at least a laser oscillator that generates laser light, a laser head that irradiates the laser light toward a workpiece, and a control unit, wherein the laser head houses at least a second beam splitter that splits incident light, which is the laser light from the laser oscillator, and reflected light reflected by the workpiece by the irradiation of the incident light, a mirror that reflects third light, which is light branched by the second beam splitter from the incident light, and a third sensor that receives fourth light, which is light reflected by the reference mirror and transmitted through or branched by the second beam splitter, and further receives fifth light, which is light branched by the second beam splitter from the reflected light, and the control unit measures a working distance from the laser head to the workpiece based on a difference between a timing at which the fourth light is received by the third sensor and a timing at which the fifth light is received by the third sensor.

[0007] The present disclosure also provides a method for measuring a working distance of laser light, which is executed by a laser processing apparatus including at least a laser oscillator that generates laser light, a laser head that irradiates the laser light toward a workpiece, and a control unit, wherein the laser head contains at least a first beam splitter that splits incident light, which is the laser light from the laser oscillator, and reflected light reflected by the workpiece by irradiating the incident light, a first sensor that receives first light, which is the incident light split by the first beam splitter, and a second sensor that receives second light, which is the reflected light split by the first beam splitter, and the method includes the steps of: acquiring, by the control unit, a timing at which the first light is received by the first sensor and a timing at which the second light is received by the second sensor; and measuring, by the control unit, a working distance from the laser head to the workpiece based on a difference between the timing at which the first light is received and the timing at which the second light is received.

[0008] The present disclosure also provides a method for measuring a working distance of laser light, which is executed by a laser processing device including at least a laser oscillator that generates a laser beam, a laser head that irradiates the laser beam toward a workpiece, and a control unit, wherein the laser head includes a second beam splitter that splits incident light, which is the laser beam from the laser oscillator, and reflected light that is reflected by the workpiece due to irradiation of the incident light, a mirror that reflects a third light that is the light branched from the incident light by the second beam splitter, and a reference mirror that reflects the light reflected by the reference mirror through the second beam splitter. a third sensor that receives a fourth light, which is a reflected or branched light, and further receives a fifth light, which is a light branched by the second beam splitter, the reflected light being split by the second beam splitter; and the control unit acquiring a timing at which the fourth light is received by the third sensor and a timing at which the fifth light is received by the third sensor; and the control unit measuring a working distance from the laser head to the workpiece based on a difference between the timing at which the fourth light is received and the timing at which the fifth light is received. Effect of the Invention

[0009] According to the present disclosure, the working distance of laser light irradiated from a laser head toward a workpiece can be measured more easily and with higher accuracy. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram showing a configuration example of a laser processing device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram showing a schematic internal structure of a first configuration example of a laser head; [Diagram 3] FIG. 13 is a schematic diagram showing the internal structure of a second example of the laser head; [Figure 4] FIG. 13 is a schematic diagram showing the internal structure of a third example of a laser head; [Diagram 5] FIG. 13 is a schematic diagram showing the internal structure of a fourth example of a laser head; [Figure 6A]FIG. 1 is a diagram showing a schematic example of the internal structure of an attachment that houses a photodiode; [Figure 6B] FIG. 1 is a diagram showing an example of the internal structure of an attachment that houses a movable mirror; [Figure 6C] FIG. 1 is a schematic diagram showing an example of the internal structure of an attachment that houses a filter and a photodiode; [Figure 7] A flowchart showing the chronological order of the calculation operation procedure of the working distance of the laser head by the laser control unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] (Background to this disclosure) In laser processing equipment, the linear distance from the bottom end of the laser head housing to the workpiece, which is the object of laser processing, is sometimes called the working distance. Hereinafter, working distance may be abbreviated to "WD". Various conventional methods for measuring this WD have been proposed.

[0012] For example, there is a method of measuring the WD by grasping the laser head with an end effector such as a robot arm or a hand at the tip, and detecting the coordinates of the position of the arm or end effector. However, while the position of the laser head needs to be accurately controlled by the robot to measure the WD, measurement errors can occur because the WD is not actually measured every time.

[0013] For example, a method is known in which the WD is measured by attaching a separate distance meter to the laser head as an attachment. There are laser, radio wave, and ultrasonic distance meters, but the laser type is often used. The laser distance meter calculates the WD by measuring the difference in the rise time between the laser light emitted from the light source and the reflected light reflected back from the workpiece. However, the need to separately install such a distance meter increases the weight burden on the laser head, and there are problems with unavoidable cost increases. In addition, since the distance meter cannot be placed directly under the light path of the light source, the WD measurement at the actual processing point is an estimated value assuming that the workpiece is horizontal. Therefore, depending on the shape of the workpiece, the measurement accuracy decreases, and it is also impossible to measure the keyhole depth.

[0014] The device of Patent Document 1 measures the depth of a weld seam (for example, a keyhole, which is a cavity during welding) during welding or joining, not the above-mentioned WD (working distance), by Optical Coherence Tomography (OCT) utilizing the coherence of light. Therefore, a laser for measuring the depth of the keyhole is required separately from the processing laser for welding or joining, and further, this technology is not suitable for measuring the WD, and there is a problem that the above-mentioned distance meter is separately required for measuring the WD.

[0015] Therefore, in the following embodiment, an example of a laser processing apparatus and a method for measuring the working distance of a laser head that more easily and accurately measures the working distance of a laser light irradiated from a laser head to a workpiece will be described.

[0016] Hereinafter, with reference to the drawings as appropriate, an embodiment specifically disclosing a laser processing apparatus and a working distance measurement method for a laser head according to the present disclosure will be described in detail. However, more detailed explanation than necessary may be omitted. For example, detailed explanation of already well-known matters and duplicate explanation of substantially the same configuration may be omitted. This is to avoid the following explanation becoming unnecessarily redundant and to facilitate understanding by those skilled in the art. Note that the attached drawings and the following explanation are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0017] 1. Definitions In the following description, the term "laser processing" has the broadest possible meaning unless otherwise expressly stated, and "processing" may be replaced with "welding", which includes the processes of soldering, melting, joining, annealing, softening, tackifying, resurfacing, peening, heat treating, fusing, sealing, and stacking.

[0018] In the following description, the terms "blue laser beam" and "blue laser" have the broadest possible meaning unless otherwise explicitly stated, and refer to a laser beam or light having a blue wavelength band (e.g., a wavelength of about 400 nm to about 500 nm).

[0019] 2. Configuration of laser processing equipment First, with reference to FIG. 1, the configuration of a laser processing apparatus 100 according to the present embodiment will be described.

[0020] 1 is a schematic diagram showing a configuration example of a laser processing apparatus 100 according to the present embodiment. In the following description, the traveling direction of the laser light LB in the optical unit 20 is sometimes referred to as the X direction, and the direction intersecting with the X direction on the surface of the workpiece 200 shown in FIG. 1 is sometimes referred to as the Y direction. The directions intersecting with each of the X direction and the Y direction are sometimes referred to as the Z direction. In addition, in a state where the manipulator 40 is stationary in the posture shown in FIG. 1, in the Z direction, the side where the laser head 60 is arranged is sometimes referred to as the upper side or upper side, and the side where the workpiece 200 is arranged with respect to the laser head 60 is sometimes referred to as the lower side or lower side.

[0021] 1, the laser processing apparatus 100 includes a laser oscillator 10, an optical unit 20, a manipulator 40, an optical fiber 30, and a laser head 60. The laser processing apparatus 100 further includes a laser control unit 71, a manipulator control unit 72, and a teaching pendant 73. A display DP1 having a function as a monitor for displaying a screen of the processing results by the laser control unit 71 is connected to the laser control unit 71.

[0022] The laser oscillator 10 generates a laser beam LB based on a command from the laser control unit 71, and outputs (emits) it toward the optical unit 20. In the present embodiment, the wavelength of the laser beam LB is, for example, about 900 nm to 1000 nm, and the output is about 1 kW to 5 kW. However, the wavelengths are not particularly limited to these values, and may be other values, for example, a blue laser beam having a wavelength of about 400 nm to 500 nm, which is a blue wavelength band. That is, based on a command from the laser control unit 71, the laser oscillator 10 can generate a laser beam having a wavelength band and output (kilowatts) corresponding to the command. The laser oscillator 10 may also include another laser light source (not shown), and emit a guide laser beam GLB (for example, visible light) for guiding from the other laser light source. The wavelength of this guide laser beam GLB is, for example, about 650 nm, and the output is about several mW to several tens of mW, which is lower than the output of the laser beam LB. The optical axis of the guide laser beam GLB is approximately aligned with the optical axis of the laser beam LB.

[0023] Although not shown, the laser oscillator 10 may include a plurality of laser modules and a beam combiner, which may be used to generate blue laser light. The laser oscillator 10 uses the beam combiner to combine laser lights of different wavelengths (within a range of approximately 400 nm to 500 nm, for example, different wavelengths such as 400 nm, 420 nm, 440 nm, and 480 nm) emitted from each of the plurality of laser modules into one blue laser light. The laser oscillator 10 may be called a Direct Diode Laser (DDL) oscillator. The laser module itself is made up of a plurality of laser diodes, and is, for example, configured as a semiconductor laser array.

[0024] In this specification, "substantially the same" or "substantially orthogonal" refers to the fact that the objects being compared are the same or orthogonal, including the processing tolerances and assembly tolerances of each component that constitutes the laser processing apparatus 100, and does not mean that the objects being compared are the same or orthogonal in the strict sense.

[0025] The optical unit 20 has a housing 21. The optical unit 20 accommodates a condensing lens 22 and a shutter 23 inside the housing 21. The condensing lens 22 condenses the laser beam LB or the guide laser beam GLB incident inside the housing 21 and makes the laser beam LB or the guide laser beam GLB incident on the optical fiber 30. The shutter 23 is provided in the housing 21 so as to be movable between the inside and outside of the optical path of the laser beam LB or the guide laser beam GLB. The shutter 23 controls the movement (in other words, the presence or absence of the incidence state of the laser beam LB or the guide laser beam GLB on the optical fiber 30) by opening and closing operation by the laser control unit 71, for example. Note that the optical unit 20 may further be provided with a condensing position adjustment mechanism (not shown) in order to align the condensing position of the laser beam LB or the guide laser beam GLB with the incident end face of the optical fiber 30.

[0026] The manipulator 40 is a known vertical six-axis robot having a first joint axis J1, a second joint axis J2, a third joint axis J3, a fourth joint axis J4, a fifth joint axis J5, and a sixth joint axis J6. The sixth joint axis J6 may be called a hand axis. The sixth joint axis J6 is provided at the tip of the robot arm 41. The sixth joint axis J6 is configured to be rotatable around a predetermined axis RA (see FIG. 1). The cable 42 houses a cooling hose (not shown) of the laser head 60 and I / O lines (not shown) such as a thermal switch.

[0027] The optical fiber 30 is connected to the optical unit 20 and the laser head 60, and transmits the laser beam LB or the guide laser beam GLB incident from the optical unit 20 to the laser head 60. Although not shown, the optical fiber 30 has one or more cores which are waveguides for the laser beam LB or the guide laser beam GLB.

[0028] The laser head 60 is attached to the sixth joint axis J6 by the manipulator 40. The laser head 60 irradiates the laser beam LB or the guide laser beam GLB transmitted from the optical fiber 30 to the laser head 60 toward the workpiece 200. As a result, the workpiece 200 is laser-machined by the laser beam LB. The laser head 60 has an internal optical system (e.g., a collimation lens, a condenser lens) and a photosensor (see FIGS. 2 to 5), and converts the laser beam LB or the guide laser beam GLB into parallel beams, and then condenses the beams on the surface of the workpiece 200. An example of the internal structure of the laser head 60 will be described later with reference to FIGS. 2 to 5.

[0029] The laser head 60 rotates together with the rotation of the sixth joint axis J6. However, the positional relationship between the laser head 60 and the sixth joint axis J6 is set so that the focal position of the laser light LB or the guide laser light GLB emitted from the laser head 60 does not fluctuate with the rotation of the laser head 60. In other words, the positional relationship between the laser head 60 and the sixth joint axis J6 is set so that the focal position of the laser light LB is located on the axis RA, which is the rotation axis of the sixth joint axis J6. In this way, for example, when the manipulator 40 is pivoted, the accuracy of the operation is improved. In other words, when the workpiece 200 is laser-machined while the sixth joint axis J6 is rotated, the focal position of the laser light LB does not fluctuate, and appropriate laser processing can be performed on a predetermined processing point.

[0030] The laser control unit 71 is electrically connected between the laser oscillator 10 and the display DP1, and controls the operation of the laser oscillator 10, while generating a screen showing the processing results of the laser control unit 71 and displaying it on the display DP1. The laser control unit 71 also controls the operation of a welding power source (not shown) connected to the laser oscillator 10. Specifically, the laser oscillator 10 controls the output of the laser light LB, the oscillation time, and the timing of starting and stopping oscillation of the laser light LB (including the guide laser light) based on the control (command) of the laser control unit 71.

[0031] The laser control unit 71 also includes a control board for measuring a working distance (WD), which is a distance from a lower end of the laser head 60 (for example, a lower end point B described later) to a surface of the workpiece 200 (for example, a surface C irradiated with laser light from the laser head 60 described later). A processor 71a and a memory 71b are mounted on the control board.

[0032] The processor 71a measures WD, which is the distance from the lower end of the laser head 60 (see above) to the surface of the workpiece 200 (see above), based on the time difference between the timing of reception (in other words, the rise time) of light received by one or more photosensors (see FIGS. 2 to 5) arranged inside the laser head 60 and the known optical distance (see FIGS. 2 to 5) stored (registered) in the memory 71b (see FIG. 7). The processor 71a generates a screen showing the measurement result (for example, a message indicating that WD is xx [m]) and displays it on the display DP1.

[0033] The memory 71b has a random access memory (RAM) and a read only memory (ROM). The RAM temporarily stores data or information acquired or generated by the processor 71a. The ROM stores programs and data used for various processes executed by the processor 71a. The memory 71b stores (registers) data of various known values ​​(see various optical distances shown in Figs. 2 to 5) referenced during the WD measurement process by the processor 71a. This data may be appropriately amended and stored (registered) as necessary in conjunction with rearrangements of various elements inside the laser head 60 at times other than when the laser processing apparatus 100 is in operation.

[0034] The manipulator control unit 72 is electrically connected to the manipulator 40 and controls the operation of the manipulator 40. Specifically, the manipulator control unit 72 controls the movement speed and movement amount of the laser head 60 connected to the manipulator 40 by controlling the rotation speed and rotation amount of the motors (not shown) connected to the first joint axis J1 to the sixth joint axis J6, respectively.

[0035] The manipulator control unit 72 controls the operation of the manipulator 40 based on a previously prepared operation program or parameters input from a teaching pendant 73. The manipulator control unit 72 also sets and stores the focal position of the laser light LB emitted from the laser head 60.

[0036] The teaching pendant 73 is a device used for storing a predetermined operation in the manipulator control unit 72. An operator actually operates the manipulator 40 using the teaching pendant 73, and stores various parameters (for example, the amount of rotation from one teaching point to the next teaching point of the motors (not shown) connected to the first joint axis J1 to the sixth joint axis J6) in the manipulator control unit 72. The teaching pendant 73 also causes the manipulator 40 to execute the operation stored in the manipulator control unit 72 again, and the various parameters may be finely corrected by the teaching pendant 73 and stored again in the manipulator control unit 72 as necessary.

[0037] The display DP1 is configured using, for example, a Liquid Crystal Display (LCD) or an organic electroluminescence (EL) display, and is connected to enable input and output of data signals between the display DP1 and the laser control unit 71. The display DP1 displays a screen showing the processing result by the laser control unit 71 (for example, a message indicating that WD is xx[m]).

[0038] 3. Laser head structure Next, the structure of the laser head 60 of the laser processing apparatus 100 according to the present embodiment will be described with reference to each of Figs. 2 to 5. The laser head 60 according to the present embodiment is any one of the laser heads 61 to 64. As an example of the laser head 60, Fig. 2 illustrates the laser head 61, Fig. 3 illustrates the laser head 62, Fig. 4 illustrates the laser head 63, and Fig. 5 illustrates the laser head 64. In the description of each of the attached drawings from Fig. 2 onwards, the laser light guided from the optical fiber 30 to the laser head 60 is the laser light LB generated by the laser oscillator 10, but it may also be the guide laser light GLB generated by the laser oscillator 10.

[0039] 3-1.I-type head example 1 Fig. 2 is a diagram showing a schematic internal structure of a first configuration example of a laser head. The laser head 61 shown in Fig. 2 is an example of what is called an I-type head. In order to simplify the explanation of Figs. 2 to 5, the above-mentioned collimation lens and condenser lens are omitted from the laser head 61 (see Fig. 2) to the laser head 64 (see Fig. 5), but these optical elements are housed in the main body of each laser head.

[0040] 2, the laser head 61 has a structure in which a main body part BD1, a tip part TP1, an attachment part AP1, and an attachment part AP2 are connected to each other and are detachable from each other. The main body part BD1 is connected to the optical fiber 30 at its upper part, and the tip part TP1 is attached to its lower part (Z direction), and further, the attachment parts AP1 and AP2 are attached to the left and right sides thereof, respectively.

[0041] The main body BD1 is a block structure that houses at least a dichroic mirror DM1 in addition to basic optical elements (e.g., a collimation lens, a condenser lens) of the laser head 61. The fixing structures between the main body BD1 and the tip part TP1, and between the main body BD1 and the attachment parts AP1 and AP2 may be existing structures, and the structural example is not particularly limited.

[0042] The dichroic mirror DM1 is an example of a first beam splitter, which reflects a part of the laser light L0 guided (incident) from the laser oscillator 10 via the optical fiber 30 at a branch point A and transmits the remaining part toward the lower end point B of the laser head 61. The first light L1, which is the laser light reflected at this branch point A, is received by a first photodiode PD1. The dichroic mirror DM1 also reflects at the branch point A the reflected light RF that is reflected by the reflecting surface of the surface C of the workpiece 200 after passing through the lower end point B of the laser head 61 due to irradiation with the laser light L0 that has transmitted through the branch point A. The second light L2, which is the laser light reflected at this branch point A, is received by a second photodiode PD2.

[0043] The tip part TP1 is attached to the lower part of the body part BD1, and irradiates the laser light focused by a collimation lens (not shown) and a focusing lens (not shown) housed in the body part BD1 toward the workpiece 200. The lower end point B is the lowest point of the tip part TP1 in the downward direction (Z direction).

[0044] The attachment part AP1 is attached to one side of the main body part BD1 and holds and houses the first photodiode PD1. The holding form of the first photodiode PD1 will be described later with reference to FIG. 6A. The first photodiode PD1 is an example of a first sensor, and receives the first light L1 reflected at the branch point A of the dichroic mirror DM1 and detects the light reception timing (i.e., the rise time at which a peak value is obtained in the light reception characteristics for each time). This detection result is input to the processor 71a of the laser control part 71 via the wiring 75.

[0045] The attachment part AP2 is attached to the other side of the main body part BD1 and holds and houses the second photodiode PD2. The holding form of the second photodiode PD2 is the same as that of the first photodiode PD1. The second photodiode PD2 is an example of a second sensor, and receives the second light L2, which is the light reflected from the branch point A of the dichroic mirror DM1 of the reflected light RF, and detects the light reception timing (i.e., the rise time at which a peak value is obtained in the light reception characteristics for each time). This detection result is input to the processor 71a of the laser control part 71 via the wiring 75.

[0046] In the configuration example of the laser head 61, the following values ​​(1) to (3) are registered in the memory 71b as known setting values. (1) First optical distance d1: Straight-line distance from branch point A of dichroic mirror DM1 to first photodiode PD1 (2) Second optical distance d2: Straight-line distance from branch point A of dichroic mirror DM1 to second photodiode PD2 (3) Third optical distance d3: Straight-line distance from branch point A of dichroic mirror DM1 to bottom end point B of laser head 61

[0047] The processor 71a of the laser control unit 71 calculates the working distance (WD) by the following formula (1) using the difference ΔT between the timing at which the first photodiode PD1 receives the first light L1 (see the rise time described above) and the timing at which the second photodiode PD2 receives the second light L2 (see the rise time described above), the first optical distance d1, the second optical distance d2, and the third optical distance d3. In formula (1), c is the speed of light.

[0048]

number

[0049] 3-2. L-type head example 1 Fig. 3 is a diagram showing a schematic internal structure of a second configuration example of a laser head. A laser head 61 shown in Fig. 3 is an example of a so-called L-type head. In the explanation of Fig. 3, the same components as those in Fig. 2 are given the same reference numerals, and explanations are simplified or omitted, and differences are explained.

[0050] 3, the laser head 62 has a structure in which a main body part BD2, a tip part TP1, an attachment part AP1, and an attachment part AP2 are connected to each other and detachable from each other. The main body part BD1 is connected to the optical fiber 30 at one side thereof, and the tip part TP1 is attached below (Z direction) it, and further, the attachment parts AP1 and AP2 are attached to the other side and above, respectively.

[0051] The main body BD2 is a block structure that houses at least a dichroic mirror DM2 in addition to basic optical elements (e.g., a collimation lens, a condenser lens) of the laser head 62. The fixing structures between the main body BD2 and the tip portion TP1, and between the main body BD2 and the attachment portions AP1 and AP2 may be existing structures, and the structural example is not particularly limited.

[0052] The dichroic mirror DM2 is an example of a first beam splitter, which transmits a part of the laser light L0 guided (incident) from the laser oscillator 10 via the optical fiber 30 at a branch point A and reflects the remaining part toward a lower end point B of the laser head 62. The first light L1, which is the laser light that has transmitted through this branch point A, is received by a first photodiode PD1. The dichroic mirror DM2 also transmits at the branch point A the reflected light RF that has passed through the lower end point B of the laser head 62 and been reflected by the reflecting surface of the surface C of the workpiece 200 due to irradiation of the laser light L0 reflected at the branch point A. The second light L2, which is the laser light that has transmitted through this branch point A, is received by a second photodiode PD2.

[0053] The attachment part AP1 is attached to the other side of the main body part BD1 and holds and houses the first photodiode PD1. The holding form of the first photodiode PD1 will be described later with reference to FIG. 6A. The first photodiode PD1 is an example of a first sensor, and receives the first light L1 transmitted through the branch point A of the dichroic mirror DM1 and detects the light reception timing (i.e., the rise time at which a peak value is obtained in the light reception characteristics for each time). This detection result is input to the processor 71a of the laser control part 71 via the wiring 75.

[0054] The attachment part AP2 is attached above the main body part BD1 and holds and houses the second photodiode PD2. The holding form of the second photodiode PD2 is the same as that of the first photodiode PD1. The second photodiode PD2 is an example of a second sensor, and receives the second light L2, which is the light that is transmitted through the branch point A of the dichroic mirror DM2 from the reflected light RF, and detects the light reception timing (i.e., the rise time at which a peak value is obtained in the light reception characteristics for each time). This detection result is input to the processor 71a of the laser control part 71 via the wiring 75.

[0055] In this embodiment, the following values ​​(1) to (3) are registered in the memory 71b as known setting values. (1) First optical distance d1: Straight-line distance from branch point A of dichroic mirror DM2 to first photodiode PD1 (2) Second optical distance d2: Straight-line distance from branch point A of dichroic mirror DM2 to second photodiode PD2 (3) Third optical distance d3: Straight-line distance from branch point A of dichroic mirror DM2 to bottom end point B of laser head 62

[0056] The processor 71a of the laser control unit 71 calculates the working distance (WD) using the difference ΔT between the timing at which the first light L1 is received by the first photodiode PD1 (see the rise time described above) and the timing at which the second light L2 is received by the second photodiode PD2 (see the rise time described above), the first optical distance d1, the second optical distance d2, and the third optical distance d3, according to the above-mentioned equation (1).

[0057] 3-3.I-type head example 2 Fig. 4 is a diagram showing a schematic internal structure of a third configuration example of a laser head. The laser head 63 shown in Fig. 4 is an example of a so-called I-type head. In the explanation of Fig. 4, the same components as those in Fig. 2 or 3 are given the same reference numerals, and the explanation is simplified or omitted, and only the different contents are explained.

[0058] 4, the laser head 63 has a structure in which a main body part BD1, a tip part TP1, an attachment part AP2, and an attachment part AP3 are connected to each other and detachable from each other. The main body part BD1 is connected to the optical fiber 30 at its upper part, and the tip part TP1 is attached to its lower part (Z direction), and further the attachment parts AP2 and AP3 are attached to the left and right sides thereof, respectively.

[0059] The main body BD1 is a block structure that houses at least a dichroic mirror DM2 in addition to basic optical elements (e.g., a collimation lens, a condenser lens) of the laser head 63. The fixing structures between the main body BD1 and the tip portion TP1, and between the main body BD1 and the attachment portions AP2 and AP3 may be existing structures, and the structural example is not particularly limited.

[0060] The dichroic mirror DM1 is an example of a second beam splitter, and reflects a part of the laser light L0 guided (incident) from the laser oscillator 10 through the optical fiber 30 at the branch point A, and transmits the remaining part toward the lower end point B of the laser head 61. The third light L3, which is the laser light reflected at this branch point A, is reflected by a reference mirror MR1 that is movable in the X direction or the -X direction within the range of the length dv. The fourth light L4, which is the light reflected by the reference mirror MR1, passes through the branch point A and is received by the second photodiode PD2. The dichroic mirror DM1 also reflects at the branch point A the reflected light RF that is reflected by the reflecting surface of the surface C of the workpiece 200 after passing through the lower end point B of the laser head 61 due to irradiation with the laser light L0 that has passed through the branch point A. The fifth light L5, which is the laser light reflected at this branch point A, is received by the second photodiode PD2 in the same manner as the fourth light L4. In addition, the remaining portion of the laser light L0 that passes through branch point A passes through lower end point B, is reflected by a reflective surface on the surface of workpiece 200 or a reflective surface of a keyhole formed in workpiece 200, is reflected at branch point A, and is received by the second photodiode PD2.

[0061] The attachment part AP3 is attached to one side of the main body part BD1, and holds and accommodates the reference mirror MR1 so that it can move in the X direction or the -X direction. The movement of the reference mirror MR1 is controlled, for example, by the processor 71a of the laser control part 71. The holding form of the reference mirror MR1 will be described later with reference to FIG. 6B. The reference mirror MR1 reflects the third light L3, which is the light reflected at the branch point A of the dichroic mirror DM1, while being moved in the X direction or the -X direction within a range of a length dv by the processor 71a. Therefore, the first optical distance d1 varies within a range of (d1+dv) according to the reflection timing of the third light L3.

[0062] The attachment part AP2 is attached to the other side of the main body part BD1 and holds and houses the second photodiode PD2. The holding form of the second photodiode PD2 will be described later with reference to FIG. 6A. The second photodiode PD2 is an example of a second sensor, and receives a fifth light L5, which is light reflected by the branch point A of the dichroic mirror DM1 from the reflected light RF, and detects the light reception timing (i.e., the rise time at which a peak value is obtained in the light reception characteristics for each time). This detection result is input to the processor 71a of the laser control part 71 via the wiring 75. The second photodiode PD2 also receives a fourth light L4, which is light reflected by the reference mirror MR1 and transmitted through the dichroic mirror DM1, and detects the light reception timing (i.e., the rise time at which a peak value is obtained in the light reception characteristics for each time). This detection result is input to the processor 71a of the laser control part 71.

[0063] In the configuration example of the laser head 63, the following values ​​are registered in the memory 71b as known setting values. (1) First optical distance d1: the straight-line distance from the branch point A of the dichroic mirror DM1 to the position where the reference mirror MR1 is closest to the dichroic mirror DM1 (2) Second optical distance d2: Straight-line distance from branch point A of dichroic mirror DM1 to second photodiode PD2 (3) Third optical distance d3: Straight-line distance from branch point A of dichroic mirror DM1 to bottom end point B of laser head 61

[0064] Here, as described above, the first optical distance d1 is a variable that varies. As described above, the first optical distance d1 is a linear distance from the branch point A of the dichroic mirror DM1 to the reference mirror MR1 that moves within the range of the length dv. In the laser head 63, the reference mirror MR1 always moves within the range of the length dv, so the first optical distance d1 varies, unlike the first photodiode PD1 of the laser head 61. Note that the reference mirror MR1 does not need to always move within the range of the length dv, and may move under the control of the processor 71a when measuring and calculating the depth of the keyhole using the principle of TD-OCT described later.

[0065] The processor 71a of the laser control unit 71 calculates the working distance (WD) by the following formula (2) using the difference ΔT between the timing at which the second photodiode PD2 receives the fourth light L4 (see the rise time described above) and the timing at which the second photodiode PD2 receives the fifth light L5 (see the rise time described above), the first optical distance d1, and the third optical distance d3. In formula (2), c is the speed of light.

[0066]

number

[0067] In addition, when measuring and calculating the depth of the keyhole, the processor 71a can also calculate the depth of the keyhole formed on the surface of the workpiece 200, which is the object of laser processing, by varying the first optical distance d1 and using the principle of Time Domain (TD)-OCT. The principle of TD-OCT is a well-known technology, so a detailed description is omitted here. For example, the laser light irradiated from the laser head 60 is reflected at an interface (reflection surface) having a difference in refractive index on the surface of the workpiece 200 or its internal structure, and enters the laser head 60 again. The reflected light reflected from the workpiece 200 and the reflected light reflected back by the reference mirror MR1 are superimposed again by the dichroic mirror DM1. Therefore, if the distances traveled by both reflected lights are equal, the two lights reinforce each other, and conversely, if there is a difference in distance, the two lights cancel each other out (optical coherence). In this way, the processor 71a moves the reference mirror MR1 within the range of length dv, and observes the position where both reflected lights interfere and reinforce each other using the detection value of the second photodiode PD2, thereby measuring at what depth in the workpiece 200 the reflective surface is located (in other words, how deep the keyhole is). Note that while calculation of the keyhole depth using equation (2) is limited to the order of millimeters, calculation of the keyhole depth using the principle of TD-OCT allows more accurate calculation on the order of nanometers to micrometers.

[0068] 3-4. L-type head example 2 Fig. 5 is a diagram showing a schematic internal structure of a fourth configuration example of a laser head. A laser head 64 shown in Fig. 5 is an example of what is called an L-shaped head. In the explanation of Fig. 5, the same components as those in Figs. 2 to 4 are given the same reference numerals, and explanations are simplified or omitted, and differences will be explained.

[0069] 5, the laser head 64 has a structure in which the main body parts BD2 and BD3, the tip part TP1, and the attachment parts AP2, AP4, and AP5 are connected to each other and are detachable from each other. The attachment part AP5 is a block structure that does not contain anything and may be omitted. The main body part BD2 is connected to the optical fiber 30 on one side thereof, and the main body part BD3 is attached below it (in the Z direction), and further, the attachment parts AP5 and AP2 are attached to the other side and above, respectively.

[0070] The main body BD2 is a block structure that houses at least a dichroic mirror DM2 in addition to basic optical elements (e.g., a collimation lens, a condenser lens) of the laser head 64. The basic optical elements described above may be housed in the main body BD3. The fixing structures between the main body BD2 and the main body BD3, and between the main body BD2 and the auxiliary parts AP2 and AP5 may be existing structures, and the structural example is not particularly limited.

[0071] The dichroic mirror DM2 is an example of a second beam splitter, and reflects the laser light L0 guided (incident) from the laser oscillator 10 via the optical fiber 30 toward the dichroic mirror DM3 of the main body BD3 at the branch point A. The dichroic mirror DM2 also transmits the light from the dichroic mirror DM3 at the branch point A. The transmitted light, that is, the fourth light L4 and the fifth light L5, are each received by the second photodiode PD2 via the filter FL2.

[0072] The main body BD3 is a block structure that houses at least the filter FL1 and the dichroic mirror DM3. The main body BD3 is connected to the optical fiber 31 on one side thereof, and has the tip TP1 attached below (in the Z direction) and the accessory AP4 attached to the other side thereof. The fixing structures between the main body BD3 and the tip TP1, and between the main body BD3 and the accessory AP4 may be existing structures, and the structural example is not particularly limited.

[0073] The filter FL1 transmits the wavelength swept laser light OLB of a specific wavelength band for use in measuring the depth of the keyhole of the workpiece 200 using the principle of swept source (SS)-OCT guided from the optical fiber 31, and blocks the passage of light of wavelength bands other than that wavelength band. The dichroic mirror DM3 is an example of a second beam splitter, and transmits a part of the light from the dichroic mirror DM2 toward the lower end point B of the laser head 64 at the branch point D, and reflects the remaining part toward the reference mirror MR2 at the branch point D. The third light L3, which is the light reflected at this branch point D, is reflected at the reference mirror MR2 and then reflected at the branch point D and proceeds toward the dichroic mirror DM2. The dichroic mirror DM3 also transmits the reflected light RF from the workpiece 200 toward the dichroic mirror DM2 at the branch point D. Further, the dichroic mirror DM3 reflects a portion of the wavelength swept laser beam OLB incident (guided) into the main body BD3 via the optical fiber 31 via the filter FL1 so as to be directed toward the workpiece 200 at the branch point D, and transmits the remaining portion so as to be directed toward the reference mirror MR2 at the branch point D. A portion of this wavelength swept laser beam OLB is reflected by a reflecting surface on the surface of the workpiece 200 or a reflecting surface of a keyhole formed in the workpiece 200, passes through the branch point D, and is received by the second photodiode PD2 via the filter FL2. A portion of the wavelength swept laser beam OLB passes through the branch point D, is reflected by the reference mirror MR2, is reflected at the branch point D, and is received by the second photodiode PD2 via the filter FL2.

[0074] The attachment part AP2 is attached above the main body part BD2, and holds and accommodates the filter FL2 and the second photodiode PD2. The holding form of the filter FL2 and the second photodiode PD2 will be described later with reference to FIG. 6C. The filter FL2 transmits the laser light LB or the wavelength swept laser light OLB in a specific wavelength band (see above), and blocks the passage of light in wavelength bands other than the specific wavelength band. The second photodiode PD2 is an example of a second sensor, and receives the fourth light L4 and the fifth light L5, which are light transmitted through the branch point A of the dichroic mirror DM2, and detects the light reception timing (i.e., the rise time at which a peak value is obtained in the light reception characteristics for each time). This detection result is input to the processor 71a of the laser control part 71 via the wiring 75.

[0075] The attachment part AP4 is attached to one side of the main body part BD3 and holds and houses the reference mirror MR2. The holding form of the reference mirror MR2 is the same as that of the reference mirror MR1. The reference mirror MR2 reflects the third light L3, which is the light reflected at the branch point D, and reflects the wavelength swept laser light OLB.

[0076] In this embodiment, the following values ​​(1) to (3) are registered in the memory 71b as known setting values. (1) First optical distance d1: Straight-line distance from branch point D of dichroic mirror DM3 to reference mirror MR2 (2) Second optical distance d2: Straight-line distance from branch point D of dichroic mirror DM3 to second photodiode PD2 (3) Third optical distance d3: Straight-line distance from branch point D of dichroic mirror DM3 to bottom end point B of laser head 61

[0077] The processor 71a of the laser control unit 71 calculates the working distance (WD) using the difference ΔT between the timing at which the second photodiode PD2 receives the fourth light L4 (see the rise time described above) and the timing at which the second photodiode PD2 receives the fifth light L5 (see the rise time described above), the first optical distance d1, and the third optical distance d3, according to the above-mentioned equation (2).

[0078] In addition, the processor 71a can calculate the depth of the keyhole formed on the surface of the workpiece 200, which is the object of laser processing, by using the principle of SS-OCT, as the frequency of the wavelength-swept laser light OLB incident (guided) to the main body BD3 fluctuates. The principle of SS-OCT is a well-known technology, so a detailed description is omitted here. For example, the frequency (in other words, the wavelength) of the wavelength-swept laser light OLB is swept (i.e., changed) in time and incident from the optical fiber 31. The processor 71a can measure at what depth in the workpiece 200 the reflection surface is located (in other words, how deep the keyhole is) by Fourier transform using an interference signal obtained by combining light reflected by the reflection surface of the keyhole formed in the workpiece 200 with light of a fixed optical path in the main body BD3 (i.e., light reflected by the reference mirror MR2).

[0079] 4. How components are held within the attachment Next, the holding form of each component in the attachment will be described with reference to Fig. 6A to Fig. 6C. Fig. 6A is a diagram showing an example of the internal structure of attachment AP1 that houses the first photodiode PD1. Fig. 6B is a diagram showing an example of the internal structure of attachment AP3 that houses the reference mirror MR1. Fig. 6C is a diagram showing an example of the internal structure of attachment AP2 that houses the filter FL2 and the second photodiode PD2.

[0080] As shown in Fig. 6A, the attachment part AP1 has a housing formed, for example, in a cylindrical or columnar shape, and holds and fixes a holder 77 for holding the first photodiode PD1 so as to contact the inner peripheral surface of the housing. A holding protrusion 76 is provided on the holder 77 so as to protrude from a surface facing the incident direction of the laser light to the attachment part AP1. A part of the holding protrusion 76 is hollowed out to form a recess, and the first photodiode PD1 is disposed in the recess while being covered. Data of the detection value of this first photodiode PD1 is transmitted to the processor 71a of the laser control part 71 via the wiring 75.

[0081] As shown in Fig. 6B, the auxiliary part AP3 has a housing formed, for example, in a cylindrical or columnar shape, and accommodates a reference mirror MR1 that has been subjected to a mirror finish so that the reference mirror MR1 can move within a range of a length dv in the X direction or the -X direction. The reference mirror MR1 has a characteristic of reflecting the incident laser light. The movement of the reference mirror MR1 is controlled by a processor 71a of the laser control part 71.

[0082] As shown in FIG. 6C, the attachment AP2 has a housing formed, for example, in a cylindrical or columnar shape, and holds and fixes a holder 79 for holding the second photodiode PD2 and a holder 78 for holding the filter FL2 so as to contact the inner circumferential surface of the housing. The holder 79 has a holding protrusion 76 protruding from a surface facing the incident direction of the laser light to the attachment AP2. A part of the holding protrusion 76 is hollowed out to form a recess, and the second photodiode PD2 is covered and arranged in the recess. Data of the detection value of the second photodiode PD2 is transmitted to the processor 71a of the laser control unit 71 via the wiring 75. In addition, the filter FL2 is fixed to the holder 78 by adhesive or the like on a surface facing the incident direction of the laser light to the attachment AP2. The holder 78 is formed of a light-transmitting resin that transmits the incident laser light.

[0083] It should be noted that the holding and fixing form described in FIG. 6A to FIG. 6C is merely one example, and it is needless to say that this embodiment does not intend to limit the holding form.

[0084] 5. Working distance measurement operation Next, the operation of measuring the working distance by the laser control unit 71 will be described with reference to Fig. 7. Fig. 7 is a flowchart showing the chronological procedure of the operation of calculating the working distance of the laser head 60 by the laser control unit 71. Each process shown in Fig. 7 is mainly executed by the processor 71a of the laser control unit 71. To simplify the explanation of Fig. 7, the laser head used in the explanation is the laser head 61 (see Fig. 2) corresponding to the I-type head example 1. However, the same can be applied to each of the other laser heads 62 to 64 described with reference to Figs. 3 to 5, respectively.

[0085] In FIG. 7, the processor 71a acquires the timing of reception of the first light L1 by the first photodiode PD1 (that is, the rise time corresponding to the time when the peak intensity of the first light L1 is obtained) from the first photodiode PD1 (step St1).

[0086] The processor 71a acquires the timing of reception of the second light L2 by the second photodiode PD2 (that is, the rise time corresponding to the time when the peak intensity of the second light L2 is obtained) from the second photodiode PD2 (step St2).

[0087] The processor 71a calculates the difference between the rise time acquired in step St1 and the rise time acquired in step St2 (step St3).

[0088] The processor 71a calculates a working distance (WD) corresponding to the distance from the lower end point B of the laser head 61 to the surface C of the workpiece 200 using a predetermined calculation formula (e.g., see formula (1) above) using the difference calculation result in step St3 and known optical distances (e.g., see the first optical distance d1, second optical distance d2, and third optical distance d3 in Figure 2) pre-registered in the memory 71b (step St4).

[0089] <About the technology disclosed herein> As described above, the present disclosure discloses the following technical ideas.

[0090] <Technology 1> A laser oscillator (laser oscillator 10) that generates laser light; A laser head (laser heads 61, 62) that irradiates the laser light toward a workpiece (workpiece 200); A control unit (laser control unit 71), The laser head includes: A first beam splitter (dichroic mirrors DM1 and DM2) that splits incident light (laser light L0), which is the laser light from the laser oscillator, and reflected light (reflected light RF) reflected by the workpiece by irradiation of the incident light; a first sensor (first photodiode PD1) that receives a first light (first light L1) that is the incident light split by the first beam splitter; and a second sensor (a second photodiode PD2) that receives a second light (a second light L2) that is the reflected light split by the first beam splitter, The control unit is measuring a working distance from the laser head to the workpiece based on a difference between a timing at which the first light is received by the first sensor and a timing at which the second light is received by the second sensor; Laser processing equipment. The first photodiode PD1 is used, for example, for power monitoring of the incident light (laser light L0) (i.e., monitoring whether or not a stable intensity output is obtained). The second photodiode PD2 is used, for example, for process monitoring of the reflected light RF (i.e., monitoring whether or not the laser processing of the workpiece 200 is performed appropriately). In the present disclosure, each of the first photodiode PD1 and the second photodiode PD2, which are already provided for other purposes, is used to measure the working distance. In addition, there is no need to attach a separate range finder to the laser head 60. This allows the laser processing device to more easily and accurately measure the working distance of the laser light irradiated from the laser head 60 to the workpiece 200 while using two photodiodes already provided for other purposes.

[0091] <Technology 2> The control unit further includes a memory (memory 71b) that stores a first optical distance (first optical distance d1) that is a distance from a branching point of the incident light at the first beam splitter to the first sensor, a second optical distance (second optical distance d2) that is a distance from the branching point to the second sensor, and a third optical distance (third optical distance d3) that is a distance from the branching point to a lower end of the laser head, and measures the working distance based on the difference, the first optical distance, the second optical distance, and the third optical distance. , The laser processing apparatus according to claim 1. This allows the laser processing apparatus to calculate the working distance geometrically and with high accuracy by using the predetermined first optical distance d1 to third optical distance d3, which are preset at the optical design stage, including the dimensions of the laser head 60, and the difference in the timing of receiving light by each photodiode.

[0092] <Technology 3> The laser head includes: A body portion (body portion BD1) that accommodates at least the first beam splitter; a first attachment portion (attachment portion AP1) that houses the first sensor; a second attachment (attachment AP2) that houses the second sensor; The above is connected to the The laser processing apparatus according to Technology 1 or Technology 2. This simplifies the configuration of the laser head 60, enables the use of common parts, and allows for flexible rearrangement of the attachment parts AP1 and AP2 with the main body part BD1 at the center.

[0093] <Technology 4> The first sensor and the second sensor are disposed opposite to each other with the first beam splitter interposed therebetween. The laser processing device according to any one of the first to third aspects of the present invention. This allows the first photodiode PD1 and the second photodiode PD2 to be arranged symmetrically with respect to the main body portion BD1 that houses the dichroic mirror DM1, and allows the laser head 61 of the I-type head to be easily configured.

[0094] <Technology 5> The first sensor and the second sensor are disposed so as to surround the first beam splitter. The laser processing device according to any one of the first to third aspects of the present invention. This makes it possible to arrange the first photodiode PD1 and the second photodiode PD2 so as to surround the main body portion BD1 that houses the dichroic mirror DM1, and thus makes it possible to easily configure the laser head 62 of the L-shaped head.

[0095] <Technology 6> A laser oscillator (laser oscillator 10) that generates laser light; A laser head (laser heads 63, 64) that irradiates the laser light toward a workpiece (workpiece 200); A control unit (laser control unit 71), The laser head includes: A second beam splitter (dichroic mirrors DM1 and DM2) that splits incident light (laser light L0), which is the laser light from the laser oscillator, and reflected light (reflected light RF) reflected by the workpiece by irradiation of the incident light; a reference mirror (reference mirror MR1, MR2) that reflects a third light (third light L3) that is the light split by the second beam splitter from the incident light; and a third sensor (second photodiode PD2) that receives a fourth light (fourth light L4) that is light reflected by the reference mirror and transmitted through or branched from the second beam splitter, and further receives a fifth light (fifth light L5) that is light that is branched by the second beam splitter from the reflected light, The control unit is measuring a working distance from the laser head to the workpiece based on a difference between a timing at which the fourth light is received by the third sensor and a timing at which the fifth light is received by the third sensor; Laser processing equipment. The second photodiode PD2 is used, for example, for process monitoring of the reflected light RF (i.e., monitoring whether or not the laser processing of the workpiece 200 is being performed appropriately). In the present disclosure, such a second photodiode PD2 that is already provided for another purpose is used to measure the working distance. Also, there is no need to attach a separate range finder to the laser head 60. This allows the laser processing apparatus to more easily and accurately measure the working distance of the laser light irradiated from the laser head 60 to the workpiece 200 while using one photodiode and a reference mirror that are already arranged for another purpose.

[0096] <Technology 7> The reference mirror is provided so as to be movable toward or away from the second beam splitter by the control unit, The control unit further includes a memory (memory 71b) that stores a fourth optical distance (first optical distance d1) that is a distance from a branching point of the incident light at the second beam splitter to the reference mirror, and a third optical distance (third optical distance d3) that is from the branching point to a lower end of the laser head, and measures the working distance based on the difference, the third optical distance, and the fourth optical distance. The laser processing apparatus according to claim 6. This allows the laser processing apparatus to calculate the working distance geometrically and with high accuracy by using the default first optical distance d1 and third optical distance d3, which are preset at the optical design stage, including the dimensions of the laser head 60, and the difference in the timing of light received by each photodiode.

[0097] <Technology 8> The control unit is a memory (memory 71b) configured to store a fifth optical distance (fifth optical distance d1) that is a distance from a branch point of the incident light at the second beam splitter to the reference mirror, and a third optical distance (third optical distance d3) from the branch point to a lower end of the laser head, measuring the working distance based on the difference, the third optical distance, and the fifth optical distance; The laser processing apparatus according to claim 6. This allows the laser processing apparatus to calculate the working distance geometrically and with high accuracy by using the default first optical distance d1 and third optical distance d3, which are preset at the optical design stage, including the dimensions of the laser head 60, and the difference in the timing of light received by each photodiode.

[0098] <Technology 9> The laser head includes: a body portion (body portions BD2 and BD3) that accommodates at least the second beam splitter; A third attachment (attachment AP3, AP4) for housing the reference mirror; a fourth attachment portion (attachment portion AP2) that houses the third sensor; The above is connected to the The laser processing device according to any one of Techniques 6 to 8. This simplifies the configuration of the laser head 60, enables the use of common parts, and allows for flexible rearrangement of the attachment parts AP3, AP4, and AP2 around the main parts BD2 and BD3.

[0099] <Technology 10> The laser light is a blue laser light having a blue wavelength band. The laser processing device according to any one of the first to ninth aspects of the present invention. As a result, when the laser processing device uses blue laser light (blue laser beam) to perform laser processing of copper-based metals, the laser processing device is able to appropriately perform laser processing based on the working distance that is the measurement result.

[0100] <Technology 11> A laser oscillator that generates a laser beam; A laser head that irradiates the laser light toward a workpiece; A method for measuring a working distance of laser light, the method being performed by a laser processing apparatus comprising at least a control unit, The laser head includes: a first beam splitter which splits incident light, which is the laser light from the laser oscillator, and reflected light reflected by the workpiece by irradiation of the incident light; a first sensor that receives a first light that is the incident light split by the first beam splitter; a second sensor that receives second light, the second light being the reflected light split by the first beam splitter; acquiring, by the control unit, a timing at which the first light is received by the first sensor and a timing at which the second light is received by the second sensor; and measuring a working distance from the laser head to the workpiece based on a difference between a timing at which the first light is received and a timing at which the second light is received by the control unit. A method for measuring the working distance of laser light. As a result, the method for measuring the working distance of laser light makes it possible to measure the working distance of laser light irradiated from the laser head 60 toward the workpiece 200 more easily and accurately, while utilizing two photodiodes that have already been arranged for another purpose.

[0101] <Technology 12> A laser oscillator that generates a laser beam; A laser head that irradiates the laser light toward a workpiece; A method for measuring a working distance of laser light, the method being performed by a laser processing apparatus comprising at least a control unit, The laser head includes: a second beam splitter that splits incident light, which is the laser light from the laser oscillator, and reflected light that is reflected by the workpiece due to irradiation of the incident light; a mirror that reflects a third light that is the light split by the second beam splitter from the incident light; a third sensor that receives a fourth light, which is the light reflected by the reference mirror and transmitted through or branched by the second beam splitter, and further receives a fifth light, which is the light reflected by the reference mirror and branched by the second beam splitter; acquiring, by the control unit, a timing at which the fourth light is received by the third sensor and a timing at which the fifth light is received by the third sensor; and measuring a working distance from the laser head to the workpiece based on a difference between a timing at which the fourth light is received and a timing at which the fifth light is received by the control unit. A method for measuring the working distance of laser light. According to the method for measuring the working distance of laser light, the working distance of laser light irradiated from the laser head 60 toward the workpiece 200 can be measured more easily and accurately by utilizing a photodiode and a reference mirror that have already been placed for another purpose.

[0102] Although various embodiments have been described above with reference to the drawings, it goes without saying that the present disclosure is not limited to such examples. It is clear that a person skilled in the art can conceive of various modifications, corrections, substitutions, additions, deletions, and equivalents within the scope of the claims, and it is understood that these also naturally belong to the technical scope of the present disclosure. In addition, the components in the various embodiments described above may be arbitrarily combined within the scope of the invention. [Industrial Applicability]

[0103] The present disclosure is useful as a laser processing apparatus and a method for measuring the working distance of a laser head, which more easily and with higher accuracy measures the working distance of laser light irradiated from a laser head toward a workpiece. [Explanation of symbols]

[0104] 10 Laser Oscillator 20 Optical unit 21 Case 22 Condenser lens 23 Shutter 30 Optical Fiber 40 Manipulator 41 Robot Arm 42 Cable 60, 61, 62, 63, 64 Laser head 71 Laser control unit 71a Processor 71b Memory 100 Laser processing equipment 200 Work DM1, DM2, DM3 Dichroic Mirrors DP1 Display PD1 First photodiode PD2 Second photodiode

Claims

1. A laser oscillator that generates a laser beam; A laser head that irradiates the laser light toward a workpiece; A control unit; The laser head includes: a first beam splitter which splits incident light, which is the laser light from the laser oscillator, and reflected light reflected by the workpiece by irradiation of the incident light; a first sensor that receives a first light that is the incident light split by the first beam splitter; a second sensor that receives second light, the second light being the reflected light split by the first beam splitter; The control unit is measuring a working distance from the laser head to the workpiece based on a difference between a timing at which the first light is received by the first sensor and a timing at which the second light is received by the second sensor; Laser processing equipment.

2. the control unit further includes a memory that stores a first optical distance, which is a distance from a branching point of the incident light at the first beam splitter to the first sensor, a second optical distance, which is a distance from the branching point to the second sensor, and a third optical distance, which is a distance from the branching point to a lower end of the laser head, and measures the working distance based on the difference, the first optical distance, the second optical distance, and the third optical distance. The laser processing device according to claim 1.

3. The laser head includes: a main body portion that accommodates at least the first beam splitter; a first appendage housing the first sensor; a second appendage housing the second sensor; The above is connected to the The laser processing device according to claim 1.

4. The first sensor and the second sensor are disposed opposite to each other with the first beam splitter interposed therebetween.

3. The laser processing apparatus according to claim 1 or 2.

5. the first sensor and the second sensor are disposed so as to surround the first beam splitter; 3. The laser processing apparatus according to claim 1 or 2.

6. A laser oscillator that generates a laser beam; A laser head that irradiates the laser light toward a workpiece; A control unit; The laser head includes: A second beam splitter that splits incident light, which is the laser light from the laser oscillator, and reflected light reflected by the workpiece by irradiation of the incident light; a reference mirror that reflects a third light beam that is the incident light beam split by the second beam splitter; a third sensor that receives a fourth light, which is the light reflected by the reference mirror and transmitted through or branched by the second beam splitter, and further receives a fifth light, which is the light reflected by the reference mirror and branched by the second beam splitter; The control unit is measuring a working distance from the laser head to the workpiece based on a difference between a timing at which the fourth light is received by the third sensor and a timing at which the fifth light is received by the third sensor; Laser processing equipment.

7. The reference mirror is provided so as to be movable toward or away from the second beam splitter by the control unit, the control unit further includes a memory that stores a fourth optical distance, which is a distance from a branch point of the incident light at the second beam splitter to the reference mirror, and a third optical distance from the branch point to a lower end of the laser head, and measures the working distance based on the difference, the third optical distance, and the fourth optical distance. The laser processing apparatus according to claim 6.

8. The control unit is a memory configured to store a fifth optical distance, which is a distance from a branch point of the incident light at the second beam splitter to the reference mirror, and a third optical distance, which is a distance from the branch point to a lower end of the laser head; measuring the working distance based on the difference, the third optical distance, and the fifth optical distance; The laser processing apparatus according to claim 6.

9. The laser head includes: a main body portion that accommodates at least the second beam splitter; a third appendage housing the reference mirror; a fourth appendage housing the third sensor; and The above is connected to the The laser processing apparatus according to claim 6.

10. The laser light is a blue laser light having a blue wavelength band. The laser processing device according to any one of claims 1 to 9.

11. A laser oscillator that generates a laser beam; A laser head that irradiates the laser light toward a workpiece; A method for measuring a working distance of laser light, the method being performed by a laser processing apparatus comprising at least a control unit, The laser head includes: a first beam splitter which splits incident light, which is the laser light from the laser oscillator, and reflected light reflected by the workpiece by irradiation of the incident light; a first sensor that receives a first light that is the incident light split by the first beam splitter; a second sensor that receives second light, the second light being the reflected light split by the first beam splitter; acquiring, by the control unit, a timing at which the first light is received by the first sensor and a timing at which the second light is received by the second sensor; and measuring a working distance from the laser head to the workpiece based on a difference between a timing at which the first light is received and a timing at which the second light is received by the control unit. A method for measuring the working distance of laser light.

12. A laser oscillator that generates a laser beam; A laser head that irradiates the laser light toward a workpiece; A method for measuring a working distance of laser light, the method being performed by a laser processing apparatus comprising at least a control unit, The laser head includes: A second beam splitter that splits incident light, which is the laser light from the laser oscillator, and reflected light reflected by the workpiece by irradiation of the incident light; a reference mirror that reflects a third light beam that is the incident light beam split by the second beam splitter; a third sensor that receives a fourth light, which is the light reflected by the reference mirror and transmitted through or branched by the second beam splitter, and further receives a fifth light, which is the light reflected by the reference mirror and branched by the second beam splitter; acquiring, by the control unit, a timing at which the fourth light is received by the third sensor and a timing at which the fifth light is received by the third sensor; and measuring a working distance from the laser head to the workpiece based on a difference between a timing at which the fourth light is received and a timing at which the fifth light is received by the control unit. A method for measuring the working distance of laser light.

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