WO2019059249A1

WO2019059249A1 - Fault detection device, laser machining system and fault detection method

Info

Publication number: WO2019059249A1
Application number: PCT/JP2018/034716
Authority: WO
Inventors: 諒石川; 山下　隆之; 同慶長安; 賢二星野; 秀明山口; 加藤　直也; 真也堂本; 清隆江泉
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2017-09-21
Filing date: 2018-09-20
Publication date: 2019-03-28
Also published as: CN111164404A; CN111164404B; JPWO2019059249A1; JP7194883B2

Abstract

This fault detection device (1) is provided with: a machining laser light source (10) which emits machining laser light; a detection laser light source (20) which emits detection laser light; a spectroscope (22) which divides the detection laser light into first partial light and second partial light; a first light receiver (24) which measures the intensity of the first partial light of the detection laser light; an optical fiber (30) which transmits the second partial light of the detection laser light and the machining laser light; a second light receiver (26) which measures the intensity of the second partial light transmitted through the optical fiber; and a determination unit (50) which determines whether there is a defect in the optical fiber on the basis of the relative ratio between the intensities of the first and second partial light respectively measured by the first and second light receivers.

Description

Failure detection device, laser processing system and failure detection method

The present disclosure relates to an optical fiber failure detection device, a laser processing system, and a failure detection method, and more particularly to an optical fiber failure detection device, a laser processing system, and a failure detection method for transmitting high-power processing laser light.

A high power processing laser beam from a direct diode laser (DDL) light source, etc. is transmitted to a processing head via an optical fiber, and the work material (work) is welded and fused by focusing and irradiating. Laser processing systems are widely used. In such an optical fiber, if the optical fiber is broken while transmitting the processing laser light, the output energy of the processing laser light is large, and thus there is a possibility that the coating resin of the optical fiber and the peripheral devices may be damaged. Therefore, a laser processing system using a high output processing laser beam is generally provided with a device for detecting a break in an optical fiber transmitting the laser beam.

Many devices for detecting a break in an optical fiber that transmits high-power laser light have been proposed. As a disconnection detection device according to the prior art, for example, a closed circuit is configured using a coated wire disposed along an optical fiber that transmits laser light, and the closed circuit is disconnected (open) by heat generated when the optical fiber is disconnected. Alternatively, it has been proposed to detect a break in an optical fiber by electrically detecting a short circuit.

Yet another disconnection detection device is to place a tube for circulating gas along the optical fiber instead of the coated wire, monitor the flow rate of the circulating gas, and when the flow rate of the circulating gas changes, disconnection of the optical fiber It is also proposed to judge the

Another disconnection detection device is a laser processing system in which a laser beam (processing laser beam) for processing a workpiece is transmitted by an optical fiber, and each light intensity of the processing laser beam incident on and emitted from the optical fiber ( A pair of light detectors that monitor the output intensity), and based on the difference in the light intensity of the processing laser light measured by each light detector or the change in the relative value, the breakage of the optical fiber or the energy loss due to the optical fiber What is detected is also used.

More specifically, the optical fiber break detection device described in Patent Document 1 includes an optical fiber transmitting high-energy processing laser light for processing a workpiece, and the vicinity of the incident end and the output end of the optical fiber. And a detector for comparing the outputs of the light receivers to detect breakage of the optical fiber.

In the optical fiber device for laser transmission described in Patent Document 2, similarly, an optical fiber for transmitting a power laser beam for processing a material to be processed and a visible light selected in the vicinity of the emission end of the optical fiber A reflection means is provided, and a light receiving detector disposed near the incident end of the optical fiber and receiving the visible light selected by the power laser light and the visible light selective reflection means. The visible light is generated by burning of the covering material of the optical fiber due to disconnection of the optical fiber or the like. And the optical fiber apparatus for laser transmission detects abnormality, such as a disconnection of an optical fiber, by comparing the optical intensity of power laser beam and visible light.

Japanese Patent Application Laid-Open No. 10-038751 Japanese Patent Application Laid-Open No. 07-266067

However, in a disconnection detection device using a coated wire or a tube for gas circulation, even if the optical fiber is not broken, the closed circuit of the coated wire separate from the optical fiber is disconnected or shorted, or When the flow rate changes, it may be erroneously detected that the optical fiber is broken. For example, in a disconnection detection device using a coated wire, when a pair of coated wires constituting a closed circuit peels off due to friction with an optical fiber, the pair of core wires of the coated wire contacts (shorts) and the disconnection detection function operates Sometimes.

Further, the techniques described in Patent Document 1 and Patent Document 2 all use a high-power laser for processing a workpiece for disconnection detection. Specifically, the processing laser beam incident on and emitted from the optical fiber (Patent Document 1), or the power laser beam incident on the optical fiber and visible light emitted from the optical fiber (Patent Document 2) are compared. , Detects breakage of the optical fiber. However, the output intensity of the laser beam (machining laser beam) for processing the material to be processed fluctuates due to the operating state or use time of the laser light source device, and the transmittance of the optical fiber changes substantially. It's easy to do. Therefore, it is difficult to detect the transmission loss and the like of the optical fiber using the optical fiber itself that transmits the processing laser light, which may cause an erroneous detection and the like.

In addition, processing laser light (patent document 1) and visible light (patent document 2) produced by burning the covering material generally have a wide wavelength range, and these wavelengths and the composition of the optical fiber (the glass molecules constituting the optical fiber Depends on the density) and easily interferes with Rayleigh scattered light (scattered light generated by light scattering phenomenon by particles smaller than the wavelength of light) generated in the optical fiber, and the processing laser light or visible light does not stabilize Similarly, false detection may be caused.

A first aspect according to the present disclosure relates to a failure detection device for an optical fiber, and the failure detection device includes a processing laser light source for emitting a processing laser beam, a detection laser light source for emitting a detection laser beam, and a detection laser beam. A spectroscope for dividing into first and second partial lights, a first light receiver for measuring the intensity of the first partial light of detection laser light, a second partial light of detection laser light and a processing laser light An optical fiber to be transmitted, a second light receiver for measuring the intensity of the second partial light transmitted by the optical fiber, and first and second partial lights measured by the first and second light receivers And a determination unit that determines whether or not there is a defect in the optical fiber based on the relative ratio of the strengths.

A second aspect according to the present disclosure relates to a failure detection device for an optical fiber, and the failure detection device includes a processing laser light source for emitting a processing laser beam, a detection laser light source for emitting a detection laser beam, and a detection laser beam. A spectroscope for dividing into first and second partial lights, a first light receiver for measuring the intensity of the first partial light of detection laser light, a second partial light of detection laser light and a processing laser light An optical fiber to be transmitted, a reflecting portion for reflecting the second partial light transmitted by the optical fiber toward the optical fiber, and a reflected portion of the reflected light of the second partial light transmitted by the optical fiber. Failure of the optical fiber based on the relative ratio of the reflected light intensity of the first partial light and the second partial light measured by the third light receiver for measuring the intensity and the first and third light receivers A determination unit that determines whether or not there is That.

A third aspect according to the present disclosure relates to a failure detection device for an optical fiber, and the failure detection device comprises a processing laser light source for emitting a processing laser beam, a detection laser light source for emitting a detection laser beam, and a detection laser beam. A spectroscope for dividing into first and second partial lights, a first light receiver for measuring the intensity of the first partial light of detection laser light, a second partial light of detection laser light and a processing laser light An optical fiber to be transmitted, a second part light partially reflected by the optical fiber toward the optical fiber and a second part transmitted by the reflection / transmission part A second light receiver for measuring the intensity of the transmitted light of the partial light; and a third light receiver for measuring the intensity of the reflected light of the second partial light reflected by the reflection / transmission section and transmitted by the optical fiber; Measured by the first, second and third light receivers The on the basis of the first partial light, and the relative ratio of the intensity of the transmitted light and reflected light of the second partial light comprising, a determination section for determining whether or not there is a defect in the optical fiber, the.

The failure detection device according to the present disclosure can detect breakage of the optical fiber with higher reliability by using the stable detection laser light transmitted by the optical fiber instead of the processing laser light.

FIG. 1 is a block diagram showing a schematic configuration of the failure detection device according to the first embodiment. FIG. 2 is a block diagram showing a schematic configuration of a failure detection device according to a second embodiment. FIG. 3 is a block diagram showing a schematic configuration of a failure detection device according to the third embodiment.

First, a schematic configuration of the present disclosure will be described. The failure detection device according to each aspect of the present disclosure includes a processing laser light source that emits processing laser light, a detection laser light source that emits detection laser light, and a spectrum that divides the detection laser light into first and second partial lights. And a first light receiver for measuring the intensity of the first partial light of the detection laser light, and an optical fiber for transmitting the second partial light of the detection laser light and the processing laser light.

A failure detection apparatus according to a first aspect comprises a second light receiver for measuring the intensity of a second partial light transmitted by an optical fiber, and the first and second light receivers measured by the first and second light receivers. And a determination unit that determines whether there is a defect in the optical fiber based on the relative ratio of the intensities of the partial light of 2. The detection laser beam has a shorter peak wavelength and a smaller half width (a width of a wavelength which is half the peak value of the peak wavelength, and a value indicating a spread degree in the wavelength direction) compared to the processing laser beam. (The wavelength band is narrower), the output intensity is smaller. Also, the detection laser beam (and thus the second partial beam) has a smaller loss of light intensity that is generated while being transmitted by the optical fiber and is more stable than the processing laser beam. The wavelength dependency of the transmission loss of an optical fiber mainly differs depending on the material of the optical fiber. In addition, the peak wavelength of the detection laser light mainly differs depending on the light source of the detection laser light. By appropriately selecting the light source of the detection laser light, it is possible to obtain the detection laser light having a smaller loss of light intensity in the optical fiber than the processing laser light. Since the determination unit according to the first aspect uses the stable detection laser light, it is configured to detect defects such as disconnection of the optical fiber with high reliability.

The failure detection device according to the second aspect includes a reflection unit that reflects the second partial light transmitted by the optical fiber toward the optical fiber, and a second portion that is reflected by the reflection unit and transmitted by the optical fiber. Based on the relative ratio of the intensities of the reflected light of the first partial light and the second partial light measured by the third light receiver that measures the intensity of the reflected light of the light and the first and third light receivers And a determination unit that determines whether or not there is a defect in the optical fiber. Since the determination unit according to the second aspect uses a stable detection laser beam, it is configured to detect a defect such as a break in the optical fiber with high reliability. In addition, the distance from the third light detector to the electrical wiring for transmitting a signal indicating the difference in light intensity can be shortened from the defect determination unit, and the configuration of the failure detection device can be simplified. .

The failure detection device according to the third aspect includes a reflection / transmission part that partially reflects the second partial light transmitted by the optical fiber toward the optical fiber and a reflection / transmission part that partially transmits the partial light. A second light receiver for measuring the intensity of the transmitted second partial light, and a third receiver for measuring the intensity of the second partial light reflected by the reflection / transmission section and transmitted by the optical fiber Optical fiber based on the relative ratio of the transmitted and reflected light intensities of the first partial light and the second partial light measured by the first, second and third light receivers of And a determination unit that determines whether or not there is a problem. The determination unit according to the third aspect is a combination of the first and second aspects, and uses a stable detection laser beam, and thus detects a defect such as a break in the optical fiber with high reliability. Is configured as.

Next, an embodiment of an optical fiber failure detection device according to the present disclosure will be described below with reference to the attached drawings. In the description of each embodiment, terms (for example, “left side” and “right side”, etc.) indicating directions are appropriately used to facilitate understanding, but this is for the purpose of explanation, and these terms are used in the present embodiment. It does not limit the disclosure. In each drawing, the electrical connection of each component of the failure detection device for an optical fiber is indicated by a solid line, and the traveling direction of each laser beam from each component (a light source or the like) is indicated by a linear arrow. Also, although the linear arrows in each drawing are shown with their optical axes shifted to clarify each laser light, in actuality, each laser light is transmitted on the same optical axis in the optical fiber. It is

First Embodiment
A first embodiment of a failure detection device 1 according to the present disclosure will be described with reference to FIG. FIG. 1 is a block diagram showing a schematic configuration of a failure detection device 1 according to the present disclosure. The failure detection device 1 according to the first embodiment is, as shown in FIG. 1, roughly: a processing laser light source 10, a detection laser light source 20, a half mirror 22 (spectrometer), and an optical fiber 30 (process fiber or transmission) Fiber), first and second light detectors 24 and 26 (light receivers), and a defect determination unit 50 (also simply referred to as a determination unit). The laser processing system according to the present disclosure includes a system control unit 60 electrically connected to the processing laser light source 10 and the failure determination unit 50 of the failure detection device 1. The laser processing system has a first storage chamber 16 and a second storage chamber 18 separated from the first storage chamber 16. The first accommodation chamber 16 accommodates the processing laser light source 10, the detection laser light source 20, the half mirrors 12 and 22, the first light detector 24, the condenser lens 36, and the defect determination unit 50. The second accommodation chamber 18 accommodates the second light detector 26, the collimation lens 38, and the beam splitter 40. The optical fiber 30 physically and optically connects the first accommodation chamber 16 and the second accommodation chamber 18. The first storage room 16 is, for example, a space defined by a housing of the apparatus or a room of a building. The same applies to the second storage chamber 18.

Processing laser light source 10 emits any processing laser light L _P of the high output for machining a workpiece (workpiece, not shown). Processing is, for example, welding, melting and drilling. Processing laser light source 10 is, for example, the peak wavelength is long, wide wavelength band (975 nm ± 20 nm), direct diode laser (DDL output intensity emits a processing laser beam _{L P} of several kW order (~ ¹⁰ 4 W) ) It may be a light source. Processing laser beam L _P, as shown, is reflected by the half mirror 12 arranged in the direction of 45 degrees to the optical axis of the processing laser light L _P, it is oriented along the optical fiber 30 (guide). Half mirror 12 is substantially totally reflects the light of the wavelength band of the processing laser light L _P, that a short light more wavelengths, such as detection laser light L _D will be described later is intended to substantially totally transmits preferable.

Detection laser light source 20 emits the detection laser beam L _D for detecting a defect such as disconnection of the optical fiber 30. Detection laser light source 20, for example, the peak wavelength than the machining laser beam _{L P} is short, the wavelength band is a narrow (600 nm ± 5 nm), helium for emitting a detection laser beam output intensity several hundred millimeters W (~ 1W) It may be a neon (He-Ne) laser light source or a semiconductor laser light source. As shown in the figure, a part of the detection laser beam L _D is a surface S ₁ downward to the left of another half mirror 22 (spectrometer) disposed at an orientation of 45 degrees with respect to the optical axis. It reflects and the rest is transmitted. That detection laser light _{L D} is divided by the surface _{S 1} of the half mirror 22 to the first partial light _{L D1} and second partial light _{L D2.} Second partial light L _D2 transmitted is incident on the optical fiber 30 to the machining laser beam L _P coaxially, the first partial light L _D1 reflected is incident on the first photodetector 24.

First photodetector 24 receives the first partial light L _D1 of the detection laser beam L _D, is to measure the light intensity of the first partial light L _D1. The first photodetector 24 provides a signal P ₁ indicating the light intensity of the first partial light L _D1 measured in fault determination unit 50.

A condensing lens 36 is disposed between the half mirror 12 and the optical fiber 30. Condenser lens 36 is for condensing the second partial light L _D2 and the processing laser light L _P of the detection laser beam L _D on the entrance end 32 of the optical fiber 30. Second partial light L _D2 and the processing laser light L _P of the detection laser light L _D emitted from the emission end 34 of the optical fiber 30 is converted into parallel light by a collimation lens 38, the optical axis of the optical fiber 30 The light beam is incident on a beam splitter 40 disposed at 45 ° orientation.

Beam splitter 40 is substantially totally reflects toward the light of the second partial light L _D2 equivalent wavelength band of the detection laser beam L _D to the second photodetector 26, equivalent to the processing laser beam L _P Substantially all the light of the wavelength band of That second partial light L _D2 of detection laser light L _D is incident on the second photodetector 26, the working laser beam L _P is irradiated on the workpiece. Although not shown, another condenser lens may be disposed between the beam splitter 40 and the second light detector 26 for condensing the second partial light _LD2 .

Second photodetector 26 receives the second partial light L _D2 of detection laser light L _D, as well as measuring the light intensity of the second partial light L _D2, the signal P ₂ indicating the light intensity It is supplied to the defect determination unit 50. The defect determination unit 50 compares the signals P ₁ and P ₂ indicating the light intensities supplied from the first and second

light detectors

24 and 26, and determines whether the optical fiber 30 has a defect such as disconnection. judge. For example, when the intensity ratio (r ₁ = P ₂ / P ₁ ) of the signals P ₁ and P ₂ is smaller than the threshold Th ₁ (r ₁ <Th ₁ ), the defect determining unit 50 determines that the optical fiber 30 has a defect. You may When the optical fiber 30 is broken, typically, not the second partial light L _D2 of the processing laser light L _P and the detection laser light L _D is emitted from the exit end 34 of optical fiber 30, the signal P The intensity of ₂ is approximately zero, and the intensity ratio r ₁ is also zero. At this time, the defect determination unit 50 can determine that the optical fiber 30 is broken. Incidentally, fault determination unit 50, instead of the intensity ratio of signals _P 1, _{P 2,} may determine the defect based on the intensity difference between the signals _P 1, _{P 2.} Furthermore, the malfunction determining unit 50 may determine a malfunction based on a change in intensity ratio of the signals P ₁ and P ₂ or a change in intensity difference. In short, the defect determination unit 50 determines whether there is a defect or a sign of a defect in the optical fiber 30 based on the relative ratio of the intensities of the first and second partial lights L _D1 and L _D2 , or Based on a change in relative ratio of intensities of the first and second partial lights L _D1 and L _D2 or a change in relative difference, a failure or a sign of failure is determined.

Also, when dirt or the like adheres to the input end 32 or the output end 34 of the optical fiber 30, the intensity ratio r ₁ of the signals P ₁ and P ₂ does not become zero, but the defect determination unit 50 determines the signals P ₁ and P by comparing the intensity ratio of ₂ r ₁ and a suitable threshold value Th _1, the processing laser light L _P is irradiated to the dirt, the state where the incident end 32 or exit end 34 of optical fiber 30 is excessively heating problem It can be properly determined as the state. Unlike the above-described background art, the failure detection device 1 according to the present disclosure detects a laser beam transmitted to the optical fiber 30 itself, instead of detecting a break in a coated wire separate from the optical fiber 30. Do. In addition, the processing laser has a wide wavelength band, and the output intensity is likely to be unstable due to the operating state or use time of the processing laser light source. Failure detection device 1, rather than such a processing laser utilizes a detection laser beam L _D. Therefore, defects such as breakage of the optical fiber 30 can be detected or determined with higher reliability.

Further, the ratio of the light intensity of the signal P ₁ indicating the light intensity of the detection laser light L _D incident on the optical fiber 30 and the light intensity of the signal P ₂ indicating the light intensity of the stable detection laser light L _D emitted from the optical fiber On the basis of the difference or the change of the relative value, it is possible to detect the failure such as the disconnection of the optical fiber 30 with high reliability.

When a defect determination unit 50 determines that the disconnection or failure occurs in the optical fiber 30, the system control unit 60 controls the processing laser light source 10 to stop immediately the exit of the processing laser light L _P high power by, damages such as a peripheral device by the working laser beam L _P leaked from the optical fiber 30 can be prevented.

Second Embodiment
A second embodiment of the failure detection device 2 according to the present disclosure will be described with reference to FIG. FIG. 2 is a block diagram showing a schematic configuration of the failure detection device 2 according to the present disclosure. The failure detection device 2 according to the second embodiment generally includes a third light detector 28 for detecting a second partial light _LD2 reciprocating in the optical fiber 30, instead of the second light detector 26. Since the configuration is the same as that of the first embodiment except for the above points, the description of the overlapping points is omitted. The third light detector 28 is accommodated in the first accommodation chamber 16.

As in the first embodiment, the failure detection device 2 according to the second embodiment generally includes the processing laser light source 10, the detection laser light source 20, the half mirror 22 (spectrometer), the optical fiber 30, and the first A light detector 24 (light receiver) and a defect determination unit 50 (determination unit) are provided. These configurations and functions are the same as in the first embodiment.

The failure detection device 2 according to the second embodiment is a diffraction grating plate 42 (also referred to as a grating or a reflection portion) disposed perpendicularly to the optical axis of the optical fiber 30, illustrated on the right side of the collimation lens 38 shown in FIG. ). Diffraction grating plate 42 in FIG. 2, substantially to the total transmitted light of the processing laser light L _P equivalent wavelength band, the light of the second partial light L _D2 equivalent wavelength band of the detection laser beam L _D The light is substantially totally reflected toward the output end 34 of the optical fiber 30. Although different from that shown in Figure 2, the diffraction grating plate 42, of the second partial light L _D2 of detection laser light L _D, is transmitted through a portion of the constant ratio, emitting the remainder of the optical fiber 30 It may be reflected towards the end 34. At this time, the relative intensity ratio between the transmitted light through which the second partial light _LD2 passes through the diffraction grating plate 42 and the reflected light reflected by the diffraction grating plate 42 is constant.

Moreover, the second partial light L _D2 of detection laser light L _D emitted from the incident end 32 of the optical fiber 30 is a view in the right upwardly facing surface S ₂ of the half mirror 22 (spectrometer), partially reflecting And the rest is transparent. However, in FIG. 2, among the second partial light LD ₂ , the linear arrows indicating transmitted light transmitted through the half mirror 22 are omitted. That is, the second partial light _{L D2} of detection laser light _{L D} is an optical fiber 30 reciprocates, a part of the light (third partial light _{L D3)} is reflected by the surface _{S 2} of the half mirror 22 , And the third light detector 28.

Third photodetector 28 receives the third partial light L _D3 of detection laser light L _D, which measures the light intensity. The third photodetector 28 supplies a signal P ₃ indicating the light intensity of the third partial light L _D3 measured in fault determination unit 50.

The defect judging unit 50 according to the second embodiment compares the signals P ₁ and P ₃ indicating the light intensities supplied from the first and third

light detectors

24 and 28 and It is determined whether or not there is a problem. For example, when the intensity ratio (r ₂ = P ₃ / P ₁ ) of the signals P ₁ and P ₃ is smaller than the threshold value Th ₂ (r ₂ <Th ₂ ), the defect determination unit 50 determines that the optical fiber 30 has a defect. You may When the optical fiber 30 is broken, typically, the third never partial light L _D3 is emitted from the incident end 32 of the optical fiber 30, the intensity of the signal P ₃ of the detection laser light L _D is approximately It is zero, and the intensity ratio r ₂ is also zero. At this time, the defect determination unit 50 can determine that the optical fiber 30 is broken.

Further, when dirt or the like adheres to the input end 32 or the output end 34 of the optical fiber 30, the intensity ratio r ₂ of the signals P ₁ and P ₃ does not become zero, but the defect determination unit 50 determines the signals P ₁ and P by comparing the ₃ intensity ratio r ₂ with a suitable threshold value Th _2, the processing laser light L _P is irradiated to the dirt, the state where the incident end 32 or exit end 34 of optical fiber 30 is excessively heating problem It can be properly determined as the state. Fault detection apparatus 2 according to the present disclosure, as described above, by utilizing the detection laser light L _D is a stable detection laser light is transmitted into the optical fiber 30 itself, a problem such as disconnection of the optical fiber 30 It can be detected or determined with higher reliability.

In addition, a signal P ₁ indicating the light intensity of the detection laser light L _D incident on the optical fiber 30 and the light intensity of the detection laser light L _D transmitted back and forth between the incident end and the light emission end of the optical fiber can be detected in each of the ratio of light intensity, the difference or change in the relative value, high reliability problem such as disconnection of the optical fiber 30 on the basis of, of the signal P ₃ indicating the.

In the second embodiment, unlike the first embodiment, both of the first and

third photodetectors

24 and 28 can be disposed adjacent to the defect determination unit 50. Specifically, the first and

third photodetectors

24 and 28 are both accommodated in the first accommodation chamber 16. The malfunction determination unit 50 is also accommodated in the first accommodation chamber 16. That is, the third light detector 28 according to the second embodiment can be disposed closer to the defect determination unit 50 than the second light detector 26 of the first embodiment. Therefore, the third can be shortened electrical wiring distance for transmitting the signals P ₃ to the fault determining unit 50 from the photodetector 28, it is possible to further simplify the configuration of the failure detection device 2.

When such a defect determination unit 50 determines that the disconnection or failure occurs in the optical fiber 30, the system control unit 60, processing laser light source to stop immediately the exit of the processing laser light L _P high power by controlling the 10, the damage such as the peripheral device according to the working laser beam L _P leaked from the optical fiber 30 can be prevented.

Third Embodiment
Third Embodiment A third embodiment of the failure detection device 3 according to the present disclosure will be described with reference to FIG. FIG. 3 is a block diagram showing a schematic configuration of the failure detection device 3 according to the present disclosure. The failure detection apparatus 3 according to the third embodiment is implemented, except that the third light detector 28 of the second embodiment is provided in addition to the second light detector 26 of the first embodiment. Since the configuration is the same as that of the first embodiment, the description of the overlapping point is omitted.

As in the first embodiment, the failure detection device 3 according to the third embodiment generally includes the processing laser light source 10, the detection laser light source 20, the half mirror 22 (spectrometer), the optical fiber 30, and the first A light detector 24 (light receiver) and a defect determination unit 50 (determination unit) are provided. These configurations and functions are the same as in the first embodiment.

The failure detection device 3 according to the third embodiment is a diffraction grating plate 42 (both a grating or a transmission / reflection portion) disposed perpendicularly to the optical axis of the optical fiber 30, illustrated on the right side of the collimation lens 38 shown in FIG. Say). The diffraction grating plate 42 of FIG. 3 transmits a part (transmitted light L _D2T ) of a constant ratio in the second partial light L _D2 of the detection laser light L _D , and the remaining (reflected light L _D2R ) as an optical fiber The light is reflected toward the emission end 34 of the T.30.

The transmitted light _LD2T transmitted by the diffraction grating plate 42 in FIG. 3 is incident on the second light detector 26 via the beam splitter 40 as in the first embodiment. Further, the reflected light L _D2R reflected by the diffraction grating plate 42 in Figure 3, is transmitted back to the optical fiber 30, as in the second embodiment, in the drawing the right upwardly facing surface S ₂ of the half mirror 22 (spectrometer) It is reflected and enters the third light detector 28.

The second light detector 26 for receiving the detection laser light on the emission end 34 side of the optical fiber 30 and the third light detector 28 for receiving the detection laser light on the incident end 32 of the optical fiber 30 are the first embodiment. and 2 and similar, receives the transmitted light _{L D2T} and the reflected light _{L D2R} of the second partial light _{L D2} of detection laser light _{L D,} to measure the light intensity, the signal _P 2 indicating the light intensity, supplying P ₃ to the fault determination unit 50.

The defect judging unit 50 according to the third embodiment compares the signals P ₁ , P ₂ and P ₃ indicating the light intensities supplied from the first, second and

third photodetectors

24, 26 and 28. It is determined whether the optical fiber 30 has a defect such as a break. For example, when the intensity ratio (r ₁ = P ₂ / P ₁ , r ₂ = P ₃ / P ₁ ) of the signals P ₁ , P ₂ and P ₃ is smaller than the threshold values Th ₁ and Th ₂ , for example It may be determined that there is a defect in the optical fiber 30 r ₁ <Th ₁ , r ₂ <Th ₂ ). When the optical fiber 30 is broken, typically, the light intensity of the transmitted light _{L D2T} and the reflected light _{L D2R} of the second partial light _{L D2} is substantially zero, the intensity ratio _r 1, _{r 2} also It is zero. At this time, the defect determination unit 50 can determine that the optical fiber 30 is broken.

When dirt or the like adheres to the input end 32 or the output end 34 of the optical fiber 30, the intensity ratios r ₁ and r ₂ of the signals P ₁ , P ₂ and P ₃ do not become zero, but the defect determination unit 50 , by comparing the signals _P _1, P 2, the intensity ratio _r 1 of _{P 3,} _{r 2} with an appropriate threshold value _Th 1, Th _2, the processing laser light _{L P} is irradiated to the dirt, the optical fiber 30 A state in which the incident end 32 or the outgoing end 34 of the light source generates heat excessively can be appropriately determined as a failure state. Failure detection apparatus 3 according to the present disclosure, as described above, by utilizing the detection laser light L _D is a stable detection laser light is transmitted into the optical fiber 30 itself, a problem such as disconnection of the optical fiber 30 It can be detected or determined with higher reliability.

Further, a signal P ₁ indicating the light intensity of the detection laser light L _D incident on the optical fiber 30, a signal P ₂ indicating the light intensity of the stable detection laser light L _D emitted from the optical fiber, and an incidence of the optical fiber the ratio of the respective light intensity of the signal P ₃ indicating the light intensity of the detection laser light L _D is transmitted back and forth between the end and the exit end, differences or changes in the relative values, of the optical fiber 30 based on, Defects such as disconnection can be detected with high reliability.

In addition to the second light detector 26 of the first embodiment, the failure detection device 3 according to the third embodiment is provided with the third light detector 28 of the second embodiment. Whether or not the fiber 30 is broken can be determined more reliably.

With such fault determination unit 50 determines the disconnection or the like of the optical fiber 30, the system control unit 60 controls the processing laser light source 10, immediately stop the emission of the processing laser light L _P high power processing laser damage such as a peripheral device by the light L _P can be prevented.

The present disclosure can be used for an optical fiber failure detection apparatus and failure detection method for transmitting high-power processing laser light.

1, 2, 3 Failure detection device 10 for optical fiber 10 Processing laser light source 12 Half mirror S ₁ , S ₂ Half mirror surface 20 Detection laser light source 22 Half mirror 24 First photodetector 26 Second photodetector 28 First detector 3 photodetector 30 optical fiber 32 incident end 34 outgoing end 36 condensing lens 38 collimation lens 40 beam splitter 42 diffraction grating plate 50 defect determination unit (determination unit)
60 system control unit _{L P} processing laser beam _{L D} detection laser light _{L D1} first partial light _{L D2} second partial light _{L D3} third partial light _{L D2R} the second partial light reflected light _{L D2T} second Partial light transmission

Claims

A processing laser light source for emitting processing laser light;
A detection laser light source for emitting detection laser light;
A spectroscope which splits the detection laser light into first and second partial lights;
A first light receiver for measuring the intensity of the first partial light of the detection laser light;
An optical fiber for transmitting the second partial light of the detection laser light and the processing laser light;
A second light receiver for measuring the intensity of the second partial light transmitted by the optical fiber;
A determination unit that determines whether the optical fiber has a defect based on the relative ratio of the intensities of the first and second partial lights measured by the first and second light receivers Failure detection device.
A processing laser light source for emitting processing laser light;
A detection laser light source for emitting detection laser light;
A spectroscope which splits the detection laser light into first and second partial lights;
A first light receiver for measuring the intensity of the first partial light of the detection laser light;
An optical fiber for transmitting the second partial light of the detection laser light and the processing laser light;
A reflecting portion for reflecting the second partial light transmitted by the optical fiber toward the optical fiber;
A third light receiver for measuring the intensity of the reflected light of the second partial light reflected by the reflection section and transmitted by the optical fiber;
Based on the relative ratio of the intensity of the reflected light of the first partial light and the second partial light measured by the first and third light receivers, it is determined whether the optical fiber has a defect A failure detection device comprising:
A processing laser light source for emitting processing laser light;
A detection laser light source for emitting detection laser light;
A spectroscope which splits the detection laser light into first and second partial lights;
A first light receiver for measuring the intensity of the first partial light of the detection laser light;
An optical fiber for transmitting the second partial light of the detection laser light and the processing laser light;
A reflective / transmissive portion that partially reflects the second partial light transmitted by the optical fiber toward the optical fiber and partially transmits the second partial light toward the optical fiber;
A second light receiver for measuring the intensity of the transmitted light of the second partial light transmitted by the reflection / transmission section;
A third light receiver for measuring the intensity of the reflected light of the second partial light reflected by the reflection / transmission section and transmitted by the optical fiber;
The optical fiber based on the relative ratio of the intensities of the transmitted light and the reflected light of the first partial light and the second partial light measured by the first, second and third light receivers. And a determination unit that determines whether there is a problem with the unit.
The second partial light of the detection laser light has a smaller loss of light intensity generated while being transmitted by the optical fiber than the processing laser light.
The failure detection device according to any one of claims 1 to 3.
The detection laser beam has a shorter peak wavelength, a smaller half width, and a smaller output intensity than the processing laser beam.
The failure detection device according to any one of claims 1 to 4.
The failure detection device according to any one of claims 1 to 5,
A control unit configured to control the failure detection device and the processing laser light source.
Emitting a detection laser beam;
Emitting a processing laser beam;
Splitting the detection laser light into first and second partial lights;
Measuring the intensity of the first partial light of the detection laser light;
Transmitting the second partial light of the detection laser light and the processing laser light by an optical fiber;
Measuring the intensity of the second partial light transmitted by the optical fiber;
Determining whether or not the optical fiber is defective based on the measured relative ratio of the intensities of the first and second partial lights.
Emitting a detection laser beam;
Emitting a processing laser beam;
Splitting the detection laser light into first and second partial lights;
Measuring the intensity of the first partial light of the detection laser light;
Transmitting the second partial light of the detection laser light and the processing laser light by an optical fiber;
Reflecting the second partial light transmitted by the optical fiber toward the optical fiber;
Measuring towards the optical fiber and measuring the intensity of the reflected light of the second partial light transmitted by the optical fiber;
Determining whether or not there is a defect in the optical fiber based on the relative ratio of the intensity of the reflected light of the first partial light and the second partial light measured, and a failure detection method comprising .
Emitting a detection laser beam;
Emitting a processing laser beam;
Splitting the detection laser light into first and second partial lights;
Measuring the intensity of the first partial light of the detection laser light;
Transmitting the second partial light of the detection laser light and the processing laser light by an optical fiber;
Reflecting the second partial light transmitted by the optical fiber partially toward the optical fiber and partially transmitting the second partial light toward the optical fiber;
Measuring the intensity of the transmitted light of the partially transmitted second partial light;
Measuring the intensity of the partially reflected light of the second partial light transmitted by the optical fiber;
Determining whether the optical fiber has a defect based on the relative ratio of the intensities of the transmitted light and the reflected light of the first partial light and the second partial light measured; Failure detection method provided with
10. The light emitting device according to claim 7, wherein the second partial light of the detection laser light has a smaller loss of light intensity generated while being transmitted by the optical fiber than the processing laser light. The fault detection method according to the above item.
The detection laser beam has a shorter peak wavelength, a smaller half width, and a smaller output intensity than the processing laser beam.
The failure detection method according to any one of claims 7 to 10.