JP7454771B1 - Laser device and laser output management method - Google Patents

Abstract

The present invention provides a laser device having an output monitoring mechanism that does not detect stray light, and a laser output management method.
[Solution] A laser light source that emits laser light with a wavelength included in a first wavelength range, an irradiation port that irradiates a part of the laser light emitted from the laser light source to a target object, and a The optical path system upstream from the irradiation port includes a monitor mechanism that monitors the output of the laser light emitted from the laser light source. Furthermore, the monitoring mechanism includes a wavelength conversion element that converts a portion of the laser light emitted from the laser light source into light having a wavelength included in a second wavelength range that is outside the first wavelength range, and It has a first photodetector that receives light included in two wavelength ranges and outputs an electrical signal, and a control section that uses the electrical signal to monitor the output of the laser light emitted from the laser light source.
[Selection diagram] Figure 4

Description

The present disclosure relates to a laser device equipped with a power monitoring mechanism and a laser output management method.

In recent years, various methods have been proposed for monitoring the beam profile and output of laser light for metal processing.

For example, Patent Document 1 proposes a method that does not require the user to be involved in laser output measurement and allows the laser output to be monitored even during material processing. In addition, the authors disclose a power monitoring device that is less susceptible to noise by using a power meter instead of a photodiode as a photodetector.

Japanese Patent Application Publication No. 2020-46390

An object of the present disclosure is to provide a laser device that can monitor laser output more accurately.

A laser device according to one aspect of the present disclosure includes a laser light source that emits laser light with a wavelength included in a first wavelength range, and irradiation that irradiates a target object with a part of the laser light emitted from the laser light source. and a monitor mechanism that monitors the output of the laser light emitted from the laser light source, the optical path system being downstream from the laser light source and upstream from the irradiation port. Furthermore, the monitoring mechanism includes a wavelength conversion element that converts a part of the laser light emitted from the laser light source into light having a wavelength included in a second wavelength range that is outside the first wavelength range; A traveling direction of light included in the second wavelength range that is converted and emitted from the incident light, and a traveling direction of the laser light included in the first wavelength range that is transmitted without being converted by the wavelength conversion element. and a first photodetector that receives light included in the second wavelength range separated by the wavelength separation mirror and outputs an electrical signal, and a wavelength separation mirror that separates the wavelength separation mirror. a second photodetector that receives the laser light in the first wavelength range and outputs an electrical signal; and a control unit that monitors the output of the laser light emitted from the laser light source using an electric signal.
Further, a laser output management method according to an aspect of the present disclosure includes a laser light source that emits laser light with a wavelength included in a first wavelength range, and a part of the laser light emitted from the laser light source that is directed to a target object. and a monitor mechanism that monitors the output of the laser light emitted from the laser light source, the optical path system being downstream from the laser light source and upstream from the irradiation port. Furthermore, the monitoring mechanism includes a wavelength conversion element that converts a part of the laser light emitted from the laser light source into light having a wavelength included in a second wavelength range that is outside the first wavelength range; A traveling direction of light included in the second wavelength range that is converted and emitted from the incident light, and a traveling direction of the laser light included in the first wavelength range that is transmitted without being converted by the wavelength conversion element. and a first photodetector that receives light included in the second wavelength range separated by the wavelength separation mirror and outputs an electrical signal, and a wavelength separation mirror that separates the wavelength separation mirror. a second photodetector that receives the laser light in the first wavelength range and outputs an electrical signal; and a control unit that monitors the output of the laser light emitted from the laser light source using an electric signal.

According to the laser device according to the present disclosure, it is possible to provide a laser device that can monitor laser output more accurately.

FIG. 1 is an external view of a laser device according to an embodiment. FIG. 2 is a conceptual diagram of a laser module according to an embodiment. FIG. 3 is a conceptual diagram of a monitor mechanism according to the first embodiment. FIG. 3 is a conceptual diagram of a monitor mechanism according to a second embodiment. FIG. 3 is a relationship diagram between laser oscillation time, signal value, and output value. FIG. 3 is a conceptual diagram of a laser device according to a third embodiment. FIG. 7 is a diagram showing a list of abnormal locations according to Embodiment 3; FIG. 6 is a diagram showing a procedure for monitoring the output of laser light using the first photodetector. FIG. 3 is a diagram showing a procedure for monitoring laser light output using a first photodetector and a second photodetector. FIG. 6 is a diagram showing a check mode procedure for a conversion coefficient in the first photodetector. FIG. 3 is a diagram showing a power control procedure for laser oscillation using a first photodetector.

Hereinafter, embodiments of a laser device according to the present disclosure will be described based on the drawings. Note that the embodiments disclosed below are all examples, and are not intended to limit the laser device according to the present disclosure. For example, the laser device according to the present disclosure will be described assuming that it uses a direct diode laser that uses wavelength synthesis technology, but is not limited to this, and is not limited to a fiber laser, a disk laser, or a direct diode laser that uses spatial synthesis technology. etc. may be used.

Further, in the embodiments disclosed below, more detailed explanation than necessary may be omitted. For example, detailed explanations of well-known matters or redundant explanations of substantially the same configurations may be omitted. This is to avoid unnecessary redundancy in the explanation and to facilitate understanding by those skilled in the art.

[How the invention came about]
Photodetectors have different sensitivity to light depending on their type. For example, a low-sensitivity photodetector such as a power meter (thermoelectric effect photodetector typified by a thermopile) is not easily affected by stray light scattered and reflected at various locations within the laser device. However, such a photodetector has a slow response speed and cannot accurately output a high-speed electrical signal on the millisecond scale, such as overshoot immediately after oscillation. On the other hand, a highly sensitive photodetector such as a photodiode has a faster response speed than a thermopile and is capable of outputting a high-speed electrical signal on the order of milliseconds. However, a highly sensitive photodetector also detects stray light scattered and reflected within the laser device, making it difficult to stably output an electrical signal. A laser device according to the present disclosure monitors laser output using light of a wavelength different from that of stray light. This makes it possible to provide a monitoring mechanism that is less susceptible to stray light even if a highly sensitive photodetector such as a photodiode is used.

[Embodiment 1]
(overall structure)
FIG. 1 is an external view of a laser device according to an embodiment. FIG. 2 is a conceptual diagram of the laser module according to the embodiment. As shown in FIG. 1, the laser device 1 includes a laser oscillator 10, a transmission fiber 40, a processing head 20, and a monitor mechanism 30a. The laser oscillator 10 is, for example, a direct diode laser using wavelength synthesis technology, and includes a plurality of laser modules 100, a laser combiner 200, and a light focusing unit 300.

As shown in FIG. 2, the laser module 100 includes a plurality of laser light sources 101, a diffraction grating 102, and an output mirror 103. The plurality of laser light sources 101 are, for example, semiconductor laser arrays, and emit laser light of different wavelengths. In this embodiment, the wavelength range of laser light emitted by the plurality of laser light sources 101 is blue laser light of 420 nm to 460 nm, and in the following description, this range will be referred to as a first wavelength range λ ₁ . However, the first wavelength range λ _1- is not limited to this range and can be appropriately selected depending on the intended laser processing. For example, near-infrared light of 950 to 1000 nm may be used as the first wavelength range λ ₁ .

The diffraction grating 102 is provided so as to wavelength-synthesize the laser light in the first wavelength range λ ₁ emitted from the laser light source 101 into one laser light LB ₁ . Further, the output mirror 103 guides the laser beam LB ₁ wavelength-combined by the diffraction grating ₁₀₂ to the laser combiner 200 shown in FIG. An external resonance system is constructed between the two. In this way, laser light LB ₁ in the first wavelength range λ ₁ wavelength-combined within the laser module 100 is emitted from the plurality of laser modules 100 .

The laser combiner 200 shown in FIG. 1 further combines the laser beams LB ₁ in the first wavelength range λ ₁ emitted from each laser module 100 into one laser beam LB ₁ and guides it to the light collection unit 300. do. Specifically, the optical axes of the laser beams _LB1 emitted from each laser module 100 are brought close to each other or coincident with each other, and the optical axes of the laser beams LB1 are coupled so that they are parallel to each other. The laser beam LB ₁ that has entered the condensing unit 300 is condensed toward the transmission fiber 40 . By configuring the laser oscillator 10 in this manner, it is possible to obtain a high-output laser device 1 with a laser output exceeding several kW.

The processing head 20 shown in FIG. 1 has an irradiation port 21. The processing head 20 shown in FIG. The laser beam LB ₁ that is incident on the transmission fiber 40 and transmitted is incident on the processing head 20 and then irradiated toward the object 50 from the irradiation port 21 .

The monitor mechanism 30a shown in FIG. 1 is configured to monitor the output of the laser light _LB1 emitted from the laser light source 101. The monitor mechanism 30a monitors the laser beam LB 1 in the first wavelength range λ ₁ emitted from the diffraction grating 102 in the laser module 100 during the optical path thereof until the laser beam LB ₁ is emitted from the irradiation port 21, in other words, from the diffraction grating 102. It is provided in the optical path system on the downstream side and upstream of the irradiation port 21. In other words, the monitor mechanism 30a may be provided inside the laser module 100, the laser combiner 200, and the focusing unit 300 that constitute the laser oscillator 10, or may be provided inside the transmission fiber 40 or the processing head 20. good. For example, when the monitor mechanism 30a is provided inside the laser module 100, it is possible to detect deterioration of the laser module itself because it measures the laser beam _LB1 immediately after oscillation. On the other hand, when the monitor mechanism 30a is provided inside the processing head 20, it becomes possible to measure the actual output of the laser beam _LB1 used for processing. Here, the optical path system includes the path through which the laser beam LB ₁ passes within the laser device 1 and the space around the path. Further, the downstream side of the optical path system refers to the side closer to the irradiation port 21, and the upstream side of the optical path system refers to the side closer to the laser light source 101. The details of the monitor mechanism will be explained below.

(Monitor mechanism)
FIG. 3 is a conceptual diagram of the monitor mechanism according to the first embodiment. As shown in FIG. 3, the monitor mechanism 30a includes a wavelength conversion element 32, a wavelength separation mirror 33, a condenser lens 34, a wavelength selection filter 35, a first photodetector 36, and a control section 38.

The wavelength conversion element 32 is, for example, a fluorescent plate containing a predetermined amount of fluorescent particles, and is configured so that the laser light LB ₁ in the first wavelength range λ ₁ wavelength-combined by the diffraction grating 102 is incident thereon. For example, 1% of the laser light LB ₁ in the first wavelength range λ ₁ that is incident on the wavelength conversion element 32 is absorbed by the aforementioned phosphor particles and wavelength-converted into light LB ₂ in the second wavelength range λ ₂ . Note that, of the laser light LB ₁ that has entered the wavelength conversion element 32, the remaining light that is not converted is emitted as the laser light LB ₁ in the first wavelength range λ ₁ . The light LB ₂ in the second wavelength range λ ₂ is light with a wavelength included in a wavelength range outside the first wavelength range λ ₁ . The relationship between the first wavelength range λ ₁ and the second wavelength range λ ₂ will be described in detail later.

Laser light LB ₁ in the first wavelength range λ ₁ and light LB ₂ in the second wavelength range λ ₂ emitted from the wavelength conversion element 32 enter the wavelength separation mirror 33 . The wavelength separation mirror 33 is, for example, a dichroic mirror, and transmits the light LB ₂ in the second wavelength range λ ₂ that is incident on the wavelength separation mirror 33 and reflects the remaining wavelength range, so that the light LB 2 in the first wavelength range λ The traveling directions of the laser beam LB ₁ of the first wavelength range LB ₁ and the light LB ₂ of the second wavelength range λ ₂ are separated. Note that the wavelength separation mirror 33 can also be configured to transmit the laser light LB ₁ in the first wavelength range λ ₁ and reflect light in the remaining wavelength range. However, considering that only about 1% of the total light is converted into light in the second wavelength range λ ₂ , it is preferable that the wavelength separation mirror 33 transmits the light LB ₂ in the second wavelength range λ ₂ .

The light LB ₂ in the second wavelength range λ ₂ that has passed through the wavelength separation mirror 33 is condensed by the condenser lens 34 . The light LB ₂ focused by the focusing lens 34 passes through the wavelength selection filter 35 and reaches the first photodetector 36 . Note that the laser beam LB ₁ in the first wavelength range λ ₁ reflected by the wavelength separation mirror 33 is guided in the direction of the irradiation port 21 and irradiated onto the object 50 .

The first photodetector 36 converts the incident light into an electrical signal and outputs the signal to the control unit 38. The first photodetector 36 is, for example, a photodiode, which has a fast response speed and can output an electrical signal in milliseconds.

The wavelength selection filter 35 is an optical element that selectively transmits light in a wavelength range including the second wavelength range _λ2 . Examples of the wavelength selection filter 35 include a bandpass filter, a highpass filter, and a lowpass filter. Alternatively, the first photodetector 36 itself may be configured to have sensitivity to light in a wavelength range including the second wavelength range _λ2 without using the wavelength selection filter 35. Note that the wavelength selection filter 35 or the first photodetector 36 may be designed to have sensitivity to a wavelength range including light in the second wavelength range _λ2 , but a wavelength range outside the first wavelength range _λ1 must be selected.

The control unit 38 monitors the laser output using the electrical signal output from the first photodetector 36. It is also possible to control the power of the laser oscillator 10 based on the result. The laser output monitoring procedure and power control procedure using the first photodetector 36 will be described later in a detailed explanation of the monitoring procedure.

Here, the relationship between the first wavelength range λ ₁ and the second wavelength range λ ₂ will be explained. As described above, the light LB ₂ in the second wavelength range λ ₂ refers to light with a wavelength included in a wavelength range outside the first wavelength range λ ₁ . However, although most of the stray light is included in the first wavelength range _λ1 , the wavelength may change somewhat due to reflection. Therefore, it is preferable to select a range for the second wavelength range λ ₂ that is separated from the first wavelength range λ ₁ by a predetermined interval. For example, in this example where the first wavelength range λ ₁ is 420 to 460 nm, it is preferable to select fluorescein, which has an emission wavelength range of 480 nm to 640 nm, as the phosphor particles. Note that the range of the second wavelength range λ ₂ is not limited to this range, and can be changed depending on the type of phosphor particles included in the phosphor screen. Furthermore, it is also possible to select the wavelength range using not only a fluorescent screen but also an up-conversion element or a nonlinear optical element. For example, if the first wavelength range λ ₁ is 950 to 1000 nm, it is possible to set the second wavelength range λ ₂ to 475 to 500 nm using a nonlinear optical element.

In general, a photodetector with a fast response speed has high sensitivity to light, so it can also sense stray light that has lower intensity than laser light. However, the first photodetector 36 according to the present disclosure performs measurement using light LB ₂ in the second wavelength range λ ₂ that is different from stray light. Therefore, even if the laser beam LB ₁ in the first wavelength range λ ₁ is unintentionally reflected within the laser device 1 and reaches the wavelength selection filter 35 and the first photodetector 36 as a stray light component, the influence can be suppressed. It becomes possible to monitor the laser output without receiving any damage. This makes it possible to accurately monitor even using a photodetector with high sensitivity to light. Furthermore, by employing a monitoring mechanism with a fast response speed and high accuracy, a configuration in which the power of the laser oscillator 10 is controlled during oscillation can be realized.

[Embodiment 2]
The monitoring method using only the light LB ₂ in the second wavelength range λ ₂ (Embodiment 1) allows accurate laser output monitoring when the conversion efficiency of the wavelength conversion element 32 changes due to deterioration of the element itself. There is a risk that you will not be able to. Therefore, in the invention according to the second embodiment, by monitoring the light in the first wavelength range λ ₁ in addition to the light in the second wavelength range λ ₂ , it is possible to
We propose a monitoring mechanism that can detect changes in the detection value of the photodetector 36. In the description of the embodiment disclosed below, only the configurations different from the first embodiment will be described.

FIG. 4 is a conceptual diagram of a monitor mechanism according to the second embodiment. The monitor mechanism 30b shown in FIG. 4 is a monitor mechanism in which a light extraction mirror 31 and a second photodetector 37 are added to the components of the monitor mechanism 30a shown in FIG. Further, the installation location of the monitor mechanism 30b is the same as that of the monitor mechanism 30a described in the overall configuration of the first embodiment.

The monitor mechanism 30b according to the second embodiment is configured such that the laser beam LB ₁ in the first wavelength range λ ₁ wavelength-combined by the diffraction grating 102 is incident on the light extraction mirror 31 . The light extraction mirror 31 reflects the laser light LB ₁ in the first wavelength range λ ₁ that has entered the light extraction mirror 31 and guides it to the irradiation port 21 , while transmitting 0.1% of the laser light LB 1 in the first wavelength range λ 1 . Partial light LB 1 of ₁ is taken out as LB ₃ . At this time, it is also possible to configure the laser beam LB ₁ used for processing to be transmitted and the partial beam LB ₃ to be reflected. Further, the light extraction mirror 31 only needs to transmit a part of the laser beam LB ₁ in the first wavelength range λ ₁ that is incident on the light extraction mirror 31, but when using a high output laser in the kilowatt class, 0.1 % or less of light is preferably transmitted.

The partial light LB ₃ in the first wavelength range λ ₁ extracted by the light extraction mirror 31 enters the wavelength conversion element 32 . The wavelength conversion element 32 converts a portion, for example 1%, of the partial light LB ₃ in the first wavelength range λ ₁ that is incident on the wavelength conversion element 32 into light LB 2 in the second wavelength range λ ₂ and outputs the converted light LB ₂ . Further, of the partial light LB ₃ that has entered the wavelength conversion element ₃₂ , the portion that is not converted is transmitted as the partial light LB ₃ in the first wavelength range λ1.

The partial light LB ₃ in the first wavelength range λ ₁ and the light LB ₂ in the second wavelength range λ ₂ emitted from the wavelength conversion element 32 enter the wavelength separation mirror 33 . The wavelength separation mirror 33 transmits the light LB ₂ in the second wavelength range λ ₂ and reflects the remaining light in the wavelength range, thereby separating the partial light LB ₃ in the first wavelength range λ ₁ and the partial light LB 3 in the second wavelength range λ ₂ . The traveling direction of the light LB ₂ is separated.

The partial light LB ₃ in the first wavelength range λ ₁ reflected by the wavelength separation mirror 33 enters the second photodetector 37 . The second photodetector 37 converts the incident light into an electrical signal and outputs the signal to the control unit 38. The second photodetector 37 is, for example, a thermopile of thermoelectric effect type, and is a photodetector capable of detecting watt class light. Note that the light LB ₂ in the second wavelength range λ ₂ that has passed through the wavelength separation mirror 33 reaches the first photodetector 36 similarly to the monitor mechanism 30a, and is converted into an electrical signal.

Here, unlike the first photodetector 36, the second photodetector 37 monitors the laser output using light in the first wavelength range _λ1 , which has the same wavelength component as the stray light. However, since the second photodetector 37 is a photodetector that detects watt class light, it can be configured to be less susceptible to stray light that is weaker than the watt class light. In this way, by extracting the partial light LB ₃ in the first wavelength range λ ₁ as light for monitoring, the laser output can be achieved by using the light in the first wavelength range λ ₁ in addition to the light in the second wavelength range λ ₂ . Monitoring becomes possible.

However, it is generally known that the thermal time constant increases with the measurable wattage, so the second photodetector 37, which can detect watt class light, stably outputs an electrical signal. It takes a certain amount of time to become able to do this. Therefore, the detection result of the second photodetector 37 is preferably used for calibrating the first photodetector 36. Calibration of the first photodetector 36 will be described in detail later.

The control unit 38 monitors the laser output using the electrical signals output from the first photodetector 36 and the second photodetector 37. Furthermore, it is also possible to calibrate the first photodetector 36 based on the detection value of the second photodetector 37. Note that the laser output monitoring procedure and calibration procedure in the second embodiment will be described later in a detailed explanation of the monitoring procedure. Furthermore, it is also possible to adjust the power of the laser oscillator 10 by comparing the output command value set by the operator with the result of the first photodetector. The power adjustment procedure will also be described later in the detailed explanation of the monitoring procedure.

In the first and second embodiments, it has been explained that the wavelength separation mirror 33 and the light extraction mirror 31 may reflect or transmit the laser beam _LB1 used for processing. However, since the influence of the thermal lens effect is small, it is preferable that the element is configured to reflect the laser beam LB ₁ used for processing, as shown in FIGS. 3 and 4.

(Calibration of first photodetector)
FIG. 5 shows the relationship between laser oscillation time, signal value, and output value. In the upper part of FIG. 5, the left side shows the relationship between the laser oscillation time and the output command value _Yc , and the right side shows the relationship between the laser oscillation time and the laser output value Y actually emitted from the irradiation port 21. It is something that The output command value _Yc refers to an arbitrary laser output value set by the operator.

In the middle part of FIG. 5, the left side shows the relationship between the laser oscillation time and the electrical signal detected by the first photodetector 36, and the right side shows the laser oscillation time and the converted output of the first photodetector 36. This shows the relationship between As shown in the middle part of FIG. 5, since the first photodetector 36 can output an electrical signal in milliseconds, the signal immediately after oscillation is also the same as the laser output value Y actually emitted from the irradiation port 21. Can be detected with the same waveform.

In the lower part of FIG. 5, the left side shows the relationship between the laser oscillation time and the electrical signal detected by the second photodetector 37, and the right side shows the relationship between the laser oscillation time and the converted output of the second photodetector 37. It is something that
As shown in the lower part of FIG. 5, the second photodetector 37, which is a thermoelectric effect photodetector, has a slower response speed than the first photodetector 36 until it can stably output an electrical signal. It takes a certain amount of time.

The converted output is a value obtained by converting the electrical signals output from the light receiving surfaces of the first photodetector 36 and the second photodetector 37 into a value close to the laser output value Y actually emitted from the irradiation port 21. It is. The first photodetector 36 and the second photodetector 37 detect signal waveforms by recording signal values over time. However, the electrical signal output by the first photodetector 36 is different from the actual laser output value Y. Therefore, the control unit 38 uses the first conversion coefficient α (W/V) to convert the electrical signal detected on the light receiving surface into a converted output similar to the actual laser output value Y, and monitors the laser output. . The second photodetector 37 uses a second conversion coefficient β (W/V) as a conversion coefficient. If the correlation between the electrical signal output from the photodetector and the actual laser output is linear and passes through the origin, the first photodetector 36 and the second photodetector 37 can each be converted with one coefficient. Although it is possible, conversion may be performed using an approximate formula using two or more coefficients depending on the correlation. By calculating the output waveform equivalent to an actual laser using the conversion coefficient, output comparison becomes easy.

In the following description, the converted outputs of the first photodetector 36 and the second photodetector 37 will be referred to as a first detection value _Y1 and a second detection value _Y2 .

As described above, the first photodetector 36 is susceptible to deterioration of the wavelength conversion element 32 itself. On the other hand, since the second photodetector 37 monitors the laser output using the first wavelength range λ ₁ , it is not affected by deterioration of the wavelength conversion element 32 itself. Therefore, after the electrical signal output from the second photodetector 37 becomes stable, the control unit 38 compares the relationship between the first detected value _Y1 and the second detected value _Y2 . Then, when it is detected that the relationship between the two detected values is outside a predetermined range (outside the calibration threshold), the first detected value _Y1 is calibrated based on the second detected value _Y2 . For example, by setting (lower limit threshold)<Y ₁ /Y ₂ <(upper limit threshold), it is determined whether the ratio of the first detected value Y ₁ and the second detected value Y ₂ is within a predetermined range. If the ratio falls outside the set range, the first conversion coefficient α is recalculated so that Y ₁ /Y ₂ =1 is approximated and applied to the first photodetector 36 . With such a configuration, it is possible to continuously monitor the laser output with high precision. Note that the calibration threshold can be set arbitrarily. Moreover, although the above described a determination method using the ratio of the first detected value _Y1 and the second detected value _Y2 , the present invention is not limited to this determination method. For example, it may be determined whether the difference between the first detected value _Y1 and the second detected value _Y2 is within the calibration threshold.

In addition, when performing laser processing where irradiation is not performed for a certain period of time, for example 1 second, it is possible to calibrate the first detected value by having the user intentionally irradiate for 1 second or more. Yes (check mode procedure). The check mode procedure will be described later in the detailed explanation of the monitor procedure.

Note that in the calibration of the first photodetector 36, the second detection value _Y2 is used as a reliable value and is not a calibration target. However, the laser beam LB ₁ emitted from the irradiation port 21 may be periodically measured using a measuring device such as a power monitor, and the second conversion coefficient β may be calibrated by comparing the measured value with the measured value.

[Embodiment 3]
The invention according to Embodiment 3 proposes a monitoring mechanism that can isolate abnormal locations. In the description of the embodiment disclosed below, only the configurations different from the first embodiment and the second embodiment will be described.

FIG. 6 is a conceptual diagram of a laser device according to Embodiment 3. FIG. 7 is a list of abnormal locations according to the third embodiment. The laser device 1 according to the third embodiment has one monitor mechanism 30 for each of the laser oscillator 10 and the processing head 20. The monitor mechanism 30 is similar to the monitor mechanism 30a or the monitor mechanism 30b.

By providing a plurality of monitor mechanisms 30 in the laser device 1, it is possible to isolate the abnormal location based on the installation location of the monitor mechanism 30 that indicates the error. For example, if the monitor mechanism 30 in the laser oscillator 10 indicates the output command value and the monitor mechanism 30 in the processing head 20 indicates a decrease in the output of the laser beam LB ₁ , a It is considered that the abnormality occurred around the transmission fiber 40 that was damaged. On the other hand, if the monitor mechanism 30 in the laser oscillator 10 and the processing head both show a decrease in the output of the laser beam LB ₁ , it is possible that there is an abnormality inside the laser oscillator 10 or that the laser light source 101 itself has deteriorated.

In addition to the configuration of the control unit 38 of Embodiment 1 or 2, the control unit 38 also performs abnormal location determination. By isolating the abnormal location, the maintenance burden can be reduced. Although FIG. 6 shows the laser device 1 having two monitor mechanisms 30, three or more monitor mechanisms 30 may be provided in the laser device 1 to improve the accuracy of determining an abnormal location. Where and how many are provided in the optical path system is selected based on cost effectiveness.

[Modified example]
Although the configuration of the present disclosure has been described above based on the embodiments, the present disclosure is not limited to the above embodiments. Further, the materials, numerical values, etc. described in the above embodiments are merely exemplified as suitable ones, and the present invention is not limited thereto. Furthermore, it is possible to make appropriate changes to the configuration of the laser device without departing from the scope of the technical idea of the present disclosure.

For example, in the case of a laser device such as a disk laser that does not require wavelength synthesis, the monitor mechanism 3
0 is provided in the optical path system downstream of the laser oscillator 10 and upstream of the irradiation port 21. That is, the most upstream optical element of the monitor mechanism 30 is configured such that the laser light LB ₁ in the first wavelength range λ ₁ emitted from the laser oscillator 10 is incident on the element.

For example, although the embodiment described above discloses the laser device 1 including the processing head 20, the laser device 1 does not necessarily need to include the processing head 20.

[Detailed explanation of monitoring procedure]
The monitoring procedure of the embodiment according to the present disclosure will be specifically described below. When the need for notification arises, the notification method is to notify the operator by displaying it on a display section (not shown) or by outputting a sound from an audio output section (not shown). Further, in the procedure shown below, the control unit 38 makes various judgments based on input values and the like. In addition, in the following description, the numerical values shown in the figures and description can be changed arbitrarily.

(Monitoring procedure using first photodetector)
FIG. 8 shows a procedure for monitoring laser light output using the first photodetector.

First, a laser oscillator is operated to start laser oscillation (step S1). Next, it is determined whether the first detection value _Y1 detected by the first photodetector 36 is 10% or less of the output command value _Yc (step S2). If the first detected value _Y1 is larger than 10% of the output command value _Yc , the operator is notified of excessive laser output (step S6) and the laser oscillation is ended (step S7). When proceeding to step S6, overshoot or the like immediately after oscillation is assumed.

If the first detected value Y ₁ is less than 10% of the output command value Y _c , it is determined whether the first detected value Y ₁ is -5% or more of the output command value Y _c (step S3). If the first detected value _Y1 is larger than -5% of the output command value _Yc , the operator is informed of the decrease in laser output (step S8), and laser oscillation is ended (step S9). When proceeding to step S8, it is assumed that the laser light source 101 or the wavelength conversion element 32 has deteriorated.

If the first detected value _Y1 is -5% or more of the output command value _Yc , it is determined whether a command to terminate laser oscillation has been issued (step S4). If the command to end laser oscillation has not been issued, the process advances to step S2 and the cycle is continued. Note that if a command to end laser oscillation has been issued, laser oscillation is ended (step S5).

(Procedure for monitoring laser light output using two photodetectors)
Details of the procedure for monitoring the output of the laser beam LB ₁ using the first photodetector and the second photodetector will be described.

FIG. 9 shows a procedure for monitoring laser light output using the first photodetector and the second photodetector. First, the laser oscillator is operated to start laser oscillation (step S20), and it is determined whether the relationship between the first detected value _Y1 and the output command value _Yc is within a threshold value (step S10 shown in FIG. 8). In step S10, if the relationship between the first detected value _Y1 and the output command value _Yc is within the calibration threshold, specifically, if the judgment result in step S3 is positive, then it is determined whether a command to end laser oscillation has been given. is determined (step S21). If a command to end laser oscillation has not been issued, it is determined whether the output command value _Yc continues for one second or more (step S22). Note that if a command to end laser oscillation has been issued, laser oscillation is ended (step S23). If the output command value _Yc does not continue for 1 second or more, the process proceeds to step S2 within step S10 again to continue the cycle.

If the output command value Y _c continues for 1 second or more, the first detected value Y ₁ and the second detected value Y ₂ are acquired simultaneously (step S24), and the first detected value Y ₁ and the second detected value It is determined whether the relationship between the detected value _Y2 is within the calibration threshold (step S25). If the relationship between the first detected value _Y1 and the second detected value _Y2 is outside the calibration threshold, the operator is notified of the detected value abnormality (step S28). After issuing a warning in step S28, the first conversion coefficient α is rewritten with reference to the second detected value _Y2 (step S29), and the process proceeds to step S24. Note that when the relationship between the first detected value _Y1 and the second detected value _Y2 is within the calibration threshold, it is determined whether the relationship between the first detected value _Y1 and the output command value _Yc is within the threshold. The process proceeds to step S10, specifically step S2 shown in FIG. Step S26 and step S27 shown in FIG. 9 are the same as step S4 and step S5 shown in FIG. 8, so a description thereof will be omitted.

(Check mode procedure for first photodetector 36)
FIG. 10 shows the check mode procedure for the first photodetector 36. By performing the check mode procedure before laser processing, even when performing laser processing in which the output command signal is 1 second or less, for example, laser processing in which laser processing is repeated sporadically in 1 second or less, the first light detection can be performed. It becomes possible to calibrate the instrument 36.

First, the laser oscillator is operated (step S40), and it is determined whether the output command value _Yc continues for one second or more (step S41). If the output command value _Yc is less than 1 second, the cycle of step S41 is continued until the determination result becomes positive. If the output command value _Yc continues for 1 second or more, the process advances to step S42. Steps S42 and S43 and steps S46 and S47 in FIG. 10 are the same as steps S24 and S25 and steps S28 and S29 in FIG. 9, so a description thereof will be omitted. Note that if the relationship between the first detected value _Y1 and the second detected value _Y2 is within the calibration threshold, the laser oscillation is ended (step S44) and the operator is informed that the first detected value is normal. (Step S45). If the relationship between the first detected value _Y1 and the second detected value _Y2 is outside the calibration threshold, after rewriting the first conversion coefficient α (step S47), the laser oscillation is terminated (step S48), The operator is informed that the calibration of the first detected value has been completed (step S49).

(Laser oscillation power control procedure according to embodiment)
FIG. 11 shows a power control procedure for laser oscillation according to the embodiment. First, the laser oscillator is operated to start laser oscillation (step S50), and it is determined whether the relationship between the first detected value _Y1 and the output command value is within a threshold value (step S51). This is similar to step S2 and step S3. The same applies to embodiments in which both the first photodetector 36 and the second photodetector 37 are used. In step S51, if the relationship between the first detected value _Y1 and the output command value matches outside the threshold, the power is adjusted and the process returns to step S51. Note that steps S52 and S53 are the same as steps S4 and S5, so the explanation will be omitted.

INDUSTRIAL APPLICABILITY The present disclosure is useful as a laser processing device equipped with a monitoring mechanism that can monitor laser output more accurately.

1 Laser device 10 Laser oscillator 20 Processing head 21 Irradiation ports 30, 30a, 30b Monitor mechanism 31 Light extraction mirror 32 Wavelength conversion element 33 Wavelength separation mirror 34 Condenser lens 35 Wavelength selection filter 36 First photodetector 37 Second Photodetector 38 Control unit 40 Transmission fiber 50 Target object 100 Laser module 101 Laser light source 102 Diffraction grating 103 Output mirror 200 Laser combiner 300 Focusing unit LB ₁ laser beam LB ₂ beams LB ₃ partial beams Y Laser output value Y _c Output command value Y ₁ First detected value Y ₂ Second detected value α First conversion coefficient β Second conversion coefficient λ ₁ First wavelength range λ ₂ Second wavelength range

Claims (12)

a laser light source that emits laser light with a wavelength included in the first wavelength range;
an irradiation port that irradiates a target object with a portion of the laser light emitted from the laser light source;
A laser device comprising: a monitor mechanism for monitoring the output of the laser light emitted from the laser light source in an optical path system downstream from the laser light source and upstream from the irradiation port,
The monitor mechanism includes a wavelength conversion element that converts a portion of the laser light emitted from the laser light source into light having a wavelength included in a second wavelength range that is outside the first wavelength range according to the intensity of the laser light. and,
Among the light incident on the wavelength conversion element, the traveling direction of the light included in the second wavelength range that is converted and emitted, and the laser included in the first wavelength range that is transmitted without being converted by the wavelength conversion element. a wavelength separation mirror that separates the traveling direction of the light;
a first photodetector that receives light included in the second wavelength range separated by the wavelength separation mirror and outputs an electrical signal;
further comprising a second photodetector that receives laser light included in the first wavelength range separated by the wavelength separation mirror and outputs an electrical signal,
A laser device comprising: a control unit that monitors an output of the laser light emitted from the laser light source using the electrical signal of the first photodetector and the electrical signal of the second photodetector . The laser device according to claim 1,
The monitor mechanism is a laser device that further includes a wavelength selection filter that selectively transmits light in a second wavelength range on the light-receiving surface side of the first photodetector. The laser device according to claim 1,
The control unit is a laser device that controls power of a laser light source based on the electric signal. The laser device according to claim 1,
The control unit issues a warning or stops laser oscillation when a relationship between a detection value of the first photodetector and an output command value that commands the output of the laser light source does not satisfy a predetermined condition. laser equipment. The laser device according to claim 4,
The relationship between the detection value of the first photodetector and the output command value that commands the output of the laser light source is the difference between the detection value of the first photodetector and the output command value, or the output command value. The laser device is calculated by the ratio of the detection value of the first photodetector to the detection value of the first photodetector. The laser device according to claim 1,
The monitor mechanism further includes a light extraction mirror that takes out a part of the laser light emitted from the laser light source and transmitted to the irradiation port,
The wavelength conversion element is a laser device that converts a part of the light extracted by the light extraction mirror into light included in a second wavelength range that is outside the first wavelength range. The laser device according to claim 1 ,
The control unit includes a first conversion coefficient and a second conversion coefficient for converting the electrical signals received by the first photodetector and the second photodetector into an output value equivalent to the laser beam emitted from the irradiation port. A laser device that calculates the conversion coefficient of. The laser device according to claim 7 ,
If the relationship between the detection value of the first photodetector and the detection value of the second photodetector does not satisfy a predetermined condition, the control unit may detect the detection value of the second photodetector based on the detection value of the second photodetector. a laser device that corrects the first conversion factor and applies it to the first photodetector; The laser device according to claim 1 ,
A laser device in which the first photodetector has a faster response speed than the second photodetector. The laser device according to any one of claims 1 to 9,
The control unit is a laser device that adjusts a current of a laser light source based on the electric signal. a laser oscillator including the laser light source;
A laser device comprising a processing head including the irradiation port,
10. The laser device according to claim 1, wherein the laser oscillator and the processing head each include one monitor mechanism. a laser light source that emits laser light with a wavelength included in the first wavelength range;
an irradiation port that irradiates a target object with a portion of the laser light emitted from the laser light source;
A laser output management method comprising: a monitor mechanism for monitoring the output of the laser light emitted from the laser light source in an optical path system downstream from the laser light source and upstream from the irradiation port,
The monitor mechanism includes:
a wavelength conversion element that converts a portion of the laser light emitted from the laser light source into light having a wavelength included in a second wavelength range that is outside the first wavelength range according to the intensity of the laser light;
Among the light incident on the wavelength conversion element, the traveling direction of the light included in the second wavelength range that is converted and emitted, and the laser included in the first wavelength range that is transmitted without being converted by the wavelength conversion element. a wavelength separation mirror that separates the traveling direction of the light;
a first photodetector that receives light included in the second wavelength range separated by the wavelength separation mirror and outputs an electrical signal;
a second photodetector that receives laser light in the first wavelength range separated by the wavelength separation mirror and outputs an electrical signal;
a control unit that monitors the output of the laser light emitted from the laser light source using the electrical signal of the first photodetector and the electrical signal of the second photodetector; Method.

Images