Laser processing head and laser processing device

Abstract

A collimator lens (21) and a focus lens (22) are provided with an AR coating (23). In the AR coating (23) a first reflectance with which a first laser light is reflected is higher than a second reflectance with which a second laser light is reflected. A detection unit (25) detects diffused light (DL) diffused by the collimator lens (21) and the focus lens (22). In the detection unit (25) a first photoreception sensitivity at which the first laser light is received is lower than a second photoreception sensitivity at which the second laser light is received.

Description

[Technical Field]

[0001] The present disclosure relates to a laser processing head and a laser processing device. [Background technology]

[0002] Conventionally, a laser processing device has been known that includes a laser light source that outputs laser light containing multiple wavelength components, an optical fiber connected to the laser light source, and a laser processing head that irradiates the laser light transmitted through the optical fiber onto an object to be processed (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-79802 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the output of the laser light used for processing may fluctuate due to deterioration of the optical system of the laser light source, misalignment of the optical axis, etc. Therefore, the inventors of the present application came up with the idea of ​​detecting diffused light from the lens that constitutes the optical system of the laser processing head in order to check the fluctuation of the output of the laser light.

[0005] However, in order to detect diffused light of laser light with significantly different wavelengths, such as infrared laser light and blue laser light, it is necessary to provide separate sensors designed to maximize sensitivity to infrared laser light and blue laser light, which increases costs.

[0006] Furthermore, when laser light including infrared laser light and blue laser light is transmitted through a lens of an optical system, providing the lens with an AR coating that has low reflectance for both infrared laser light and blue laser light increases costs.

[0007] The present disclosure has been made in consideration of the above points, and its purpose is to enable accurate detection of fluctuations in the output of laser light containing different wavelengths while keeping costs down. [Means for solving the problem]

[0008] A first invention is a laser processing head that emits laser light, the laser light including a first laser light of a first wavelength and a second laser light of a second wavelength, and is equipped with a transmission fiber that transmits the laser light, a collimator lens that collimates the laser light transmitted by the transmission fiber, a focus lens that collects the laser light collimated by the collimator lens, and a detection unit that detects diffused light diffused from at least one of the collimator lens and the focus lens, wherein at least one of the collimator lens and the focus lens is provided with an AR coating, and the AR coating has a first reflectivity that reflects the first laser light that is higher than a second reflectivity that reflects the second laser light, and the detection unit has a first light receiving sensitivity that receives the first laser light that is lower than a second light receiving sensitivity that receives the second laser light.

[0009] In a first aspect of the present invention, an AR coating is provided on at least one of the collimator lens and the focus lens, diffusing the diffused light. In the AR coating, a first reflectance is higher than a second reflectance. The diffused light is detected by a detection unit. In the detection unit, a first light-receiving sensitivity is lower than a second light-receiving sensitivity.

[0010] In this way, by making the first reflectance higher than the second reflectance in the AR coating, that is, by making the second reflectance lower than the first reflectance, costs can be reduced compared to when both the first reflectance and the second reflectance are low.

[0011] Here, because the first reflectance is higher than the second reflectance, the amount of diffused light incident on the detection unit is greater for the diffused light of the first wavelength than for the diffused light of the second wavelength. Therefore, by making the first light-receiving sensitivity of the detection unit lower than the second light-receiving sensitivity, it is possible to accurately detect fluctuations in the total power of laser light including the first wavelength and the second wavelength.

[0012] A second invention is the first invention, wherein when the first reflectance is a, the first light sensitivity is 1 / a, and when the second reflectance is b, the second light sensitivity is 1 / b.

[0013] In the second invention, when the first reflectance is a, the first light sensitivity is set to 1 / a, and when the second reflectance is b, the second light sensitivity is set to 1 / b. In this way, by setting the light sensitivity of the detection unit to decrease as the reflectance of the laser light increases, fluctuations in the total power of the laser light can be detected with high accuracy.

[0014] A third invention is the first or second invention, wherein an output of the second laser light is higher than an output of the first laser light.

[0015] In the third invention, the output of the second laser beam is higher than the output of the first laser beam. Here, in the AR coating, the first reflectance of the first laser beam is higher than the second reflectance of the second laser beam. This allows more of the low-power first laser beam to be incident on the detection unit than the high-power second laser beam, thereby reducing the load on the detection unit.

[0016] A fourth invention is a laser processing apparatus comprising a laser processing head according to any one of the first to third inventions, a laser oscillator connected to the incident end of the transmission fiber and emitting laser light including a first wavelength and a second wavelength, and a control unit that controls the output of the laser oscillator based on the detection value of the detection unit.

[0017] In a fourth aspect of the present invention, a laser beam emitted from a laser oscillator is incident on the laser processing head according to any one of the first to third aspects of the present invention via a transmission fiber, thereby forming a laser processing device. The control unit controls the output of the laser oscillator based on the detected value of the detection unit.

[0018] As a result, for example, when the detected value is smaller than a predetermined threshold, the output of the laser oscillator can be increased to correct the output of the laser light.

[0019] A fifth aspect of the present invention is based on the fourth aspect of the present invention, and further includes a notification unit that performs a predetermined notification operation based on the detection value of the detection unit.

[0020] In the fifth aspect of the present invention, the notifying unit performs a predetermined notifying operation based on the detection value of the detecting unit. For example, if the detection value is smaller than a predetermined threshold, it determines that the output of the laser light has decreased, and performs a notifying operation such as sounding an alarm buzzer, turning on an alarm lamp, or displaying an alarm message.

[0021] This allows the operator to determine when maintenance of the laser processing device is required based on the predetermined notification operation. [Effects of the Invention]

[0022] According to the present disclosure, it is possible to accurately detect fluctuations in the output of laser light that includes different wavelengths. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a schematic diagram of the laser processing device according to this embodiment. [Figure 2] FIG. 2 is a diagram showing the configuration of the laser processing head. [Figure 3] FIG. 3 is a graph showing the relationship between the wavelength of the laser light and the reflectance of the AR coating. [Figure 4] FIG. 4 is a graph showing the relationship between the wavelength of the laser light and the light-receiving sensitivity of the detector. [Figure 5] FIG. 5 is a graph showing the change over time in output energy of a laser beam. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the following description of the preferred embodiments is merely exemplary in nature and is not intended to limit the present disclosure, its applications, or its uses.

[0025] <Configuration of laser processing device> As shown in FIG. 1, the laser processing device 1 includes a laser oscillator 10, a transmission fiber 15, a laser processing head 20, a robot 16, and a control unit 30.

[0026] The laser oscillator 10 is connected to the input end of the transmission fiber 15. The laser oscillator 10 includes a first laser module 11, a second laser module 12, and a beam combiner 13.

[0027] The first laser module 11 oscillates a first laser beam LB1 having a first wavelength. The first laser beam LB1 is, for example, a blue laser beam. The first laser beam LB1 is incident on a beam combiner 13.

[0028] The second laser module 12 oscillates a second laser light LB2 having a second wavelength. The output of the second laser light LB2 is higher than the output of the first laser light LB1. The second laser light LB2 is, for example, an infrared laser light. The second laser light LB2 is incident on the beam combiner 13.

[0029] The beam combiner 13 combines the first laser light LB1 and the second laser light LB2 into one laser light LB. The laser light LB combined by the beam combiner 13 is focused by a focusing lens (not shown) and then input to a transmission fiber 15.

[0030] For example, a solid-state laser light source, a gas laser light source, or a fiber laser light source can be used as the laser oscillator 10. The laser oscillator 10 may also be a semiconductor laser light source that directly uses light emitted from a semiconductor laser, or a semiconductor laser array that includes multiple laser light emitters.

[0031] The laser processing head 20 is connected to the output end of the transmission fiber 15. The laser light LB output from the laser oscillator 10 is transmitted to the laser processing head 20 via the transmission fiber 15.

[0032] The laser processing head 20 is attached to the robot 16. The laser processing head 20 is capable of changing the emission position and focal position of the laser light LB relative to the workpiece W by operating the robot 16.

[0033] The control unit 30 is connected to the laser oscillator 10, the laser processing head 20, and the robot 16. The control unit 30 controls the movement speed of the laser processing head 20 as well as the start and stop of output of the laser light LB, the output intensity of the laser light LB, and the like.

[0034] The control unit 30 is connected to a notification unit 35. The notification unit 35 performs a predetermined notification operation, such as sounding an alarm buzzer, turning on an alarm lamp, or displaying an alarm message.

[0035] The control unit 30 has a determination unit 31. The determination unit 31 determines fluctuations in the output of the laser processing head 20, as will be described in detail later.

[0036] <Configuration of laser processing head> As shown in FIG. 2, the laser processing head 20 has a collimator lens 21, a focus lens 22, and a detection unit 25.

[0037] The collimator lens 21 collimates the laser light LB emitted from the emission end of the transmission fiber 15 .

[0038] The focus lens 22 focuses the laser light LB that has been collimated by the collimator lens 21. The laser light LB focused by the focus lens 22 is emitted to the workpiece W.

[0039] When the laser light LB passes through the collimator lens 21 and the focus lens 22, a part of the laser light LB is diffused.

[0040] The detector 25 detects the diffused light DL diffused by the collimator lens 21 and the focus lens 22. The detector 25 has a first light-receiving sensitivity for receiving the first laser light LB1 that is lower than a second light-receiving sensitivity for receiving the second laser light LB2. The detection value of the detector 25 is sent to the controller 30.

[0041] The collimator lens 21 and the focus lens 22 are provided with an AR coating 23. The AR coating 23 has a first reflectance a for reflecting the first laser light LB1 that is higher than a second reflectance b for reflecting the second laser light LB2 (see FIG. 3).

[0042] In this way, by making the first reflectance a higher than the second reflectance b in the AR coating 23, that is, by making the second reflectance b lower than the first reflectance a, costs can be reduced compared to when both the first reflectance a and the second reflectance b are low.

[0043] Here, since the first reflectance a is higher than the second reflectance b, the amount of diffused light DL incident on the detecting unit 25 is greater for the diffused light DL of the first wavelength than for the diffused light DL of the second wavelength.

[0044] Therefore, by making the first light receiving sensitivity of the detecting section 25 lower than the second light receiving sensitivity, it is possible to accurately detect fluctuations in the total power of the laser light LB including the first wavelength and the second wavelength.

[0045] Specifically, when the first reflectance of the AR coating 23 is a, the first light sensitivity of the detecting unit 25 is 1 / a. Also, when the second reflectance of the AR coating 23 is b, the second light sensitivity of the detecting unit 25 is 1 / b (see FIG. 4).

[0046] In this way, by setting the light receiving sensitivity of the detecting unit 25 to be lower as the reflectance of the AR coating 23 becomes higher, it is possible to detect fluctuations in the total power of the laser light LB with high precision.

[0047] Furthermore, since the first laser light LB1 is blue laser light and the second laser light LB2 is infrared laser light, the output of the second laser light LB2 is higher than the output of the first laser light LB1.

[0048] Here, in the AR coating 23, the first reflectance a of the first laser light LB1 is higher than the second reflectance b of the second laser light LB2. As a result, more of the low-power first laser light LB1 is incident on the detecting unit 25 than the high-power second laser light LB2, and the load on the detecting unit 25 can be reduced.

[0049] The control unit 30 controls the output of the laser oscillator 10 based on the detected value of the detection unit 25. Specifically, the control unit 30 has a determination unit 31. The determination unit 31 determines fluctuations in the output of the laser processing head 20.

[0050] 5, the output of the laser light LB fluctuates when a problem such as deterioration of the optical system or misalignment of the optical axis occurs in the laser oscillator 10. Therefore, the determination unit 31 determines whether the energy of the diffused light DL detected by the detection unit 25 is smaller than a predetermined threshold value.

[0051] In the determination unit 31, when the energy of the diffused light DL becomes smaller than a threshold value, it is determined that an abnormality has occurred in the laser oscillator 10.

[0052] Then, the control unit 30 corrects the output of the laser beam LB by increasing the output of the laser oscillator 10 based on the determination result of the determination unit 31.

[0053] The notification unit 35 performs a predetermined notification operation indicating an abnormality in the laser oscillator 10 based on the determination result of the determination unit 31 (see FIG. 1). For example, if the detection value of the detection unit 25 is smaller than a predetermined threshold, it determines that the output of the laser light LB has decreased, and performs a notification operation such as sounding an alarm buzzer, turning on an alarm lamp, or displaying an alarm message.

[0054] This allows the operator to determine when maintenance of the laser processing device 1 is required based on the predetermined notification operation.

[0055] Other Embodiments The above embodiment may be configured as follows.

[0056] In this embodiment, the detection unit 25 detects the diffused light DL diffused from both the collimator lens 21 and the focus lens 22, but this is not limited to this. For example, the detection unit 25 may detect the diffused light DL diffused from either the collimator lens 21 or the focus lens 22. [Industrial Applicability]

[0057] As described above, the present disclosure is extremely useful and has high industrial applicability because it can achieve the highly practical effect of accurately detecting fluctuations in the output of laser light containing different wavelengths while keeping costs down. [Explanation of symbols]

[0058] 1. Laser processing equipment 10 Laser oscillator 15 Transmission Fiber 20 Laser processing head 21 Collimator lens 22 Focus Lens 23 AR Court 25 Detector 30 Control Unit 35 Information Department DL Diffused Light LB laser light LB1 First laser beam LB2 Second laser beam

Claims

1. A laser processing head that emits laser light, the laser light includes a first laser light having a first wavelength and a second laser light having a second wavelength; a transmission fiber for transmitting the laser light; a collimator lens for collimating the laser light transmitted through the transmission fiber; a focus lens that collects the laser light collimated by the collimator lens; a detection unit that detects diffused light diffused from at least one of the collimator lens and the focus lens, At least one of the collimator lens and the focus lens is provided with an AR coating; the AR coating has a first reflectance at which the first laser beam is reflected that is higher than a second reflectance at which the second laser beam is reflected; The detection unit is a laser processing head, and a first light receiving sensitivity for receiving the first laser light is lower than a second light receiving sensitivity for receiving the second laser light.

2. In claim 1, when the first reflectance is a, the first light receiving sensitivity is 1 / a, A laser processing head, wherein when the second reflectance is b, the second light receiving sensitivity is 1 / b.

3. In claim 1 or 2, A laser processing head, wherein the output of the second laser light is higher than the output of the first laser light.

4. A laser processing head according to any one of claims 1 to 3; a laser oscillator connected to an input end of the transmission fiber and configured to emit laser light having a first wavelength and a second wavelength; a control unit that controls an output of the laser oscillator based on a detection value of the detection unit.

5. In claim 4, A laser processing device comprising an alarm unit that performs a predetermined alarm operation based on a detection value of the detection unit.

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