Machining status monitoring system and machining status monitoring method

Abstract

To reduce missing of monitoring of a machining status in laser machining.SOLUTION: A machining status monitoring system monitors a machining status when a machining object is machined by irradiating a machining place of a machining object with a laser beam while scanning it. The machining status monitoring system includes an imaging device for imaging the machining place, and a control part for controlling driving of the imaging device. When at least a part of the machining place is scanned with a laser beam made to irradiate the machining place while overlapping it, the control part provides delay time from a start time of irradiation of the machining place with a laser beam and starts exposure of the imaging device, and finishes the exposure of the imaging device after a finish time of irradiation of the machining place with a laser beam. The length of the delay time is a length of time of irradiation of the machining place with a laser beam while overlapping it.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present disclosure relates to a processing status monitoring system and a processing status monitoring method for monitoring the processing status in laser processing.

Background Art

[0002] Conventionally, a technique of performing laser processing by irradiating a processing object while scanning it with a laser beam is known. At this time, monitoring of the processing status in laser processing may be performed for recording the processing status and detecting the occurrence of processing defects.

[0003] For example, Patent Document 1 discloses a laser welding status monitoring device that photographs the welding status of a processing object irradiated with a laser beam using a high-speed camera and records the welding status.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present disclosure provides a processing status monitoring system and a processing status monitoring method that can reduce oversights in monitoring the processing status in laser processing.

Means for Solving the Problems

[0006] A machining condition monitoring system according to an aspect of the present disclosure is a machining condition monitoring system that monitors the machining condition when machining a workpiece by irradiating a machining portion of the workpiece while scanning with a laser beam. The system includes an imaging device that images the machining portion and a control unit that controls the driving of the imaging device. When the laser beam irradiated to the machining portion scans while overlapping at least a part of the machining portion, the control unit starts the exposure of the imaging device after providing a delay time from the start time of the irradiation of the laser beam to the machining portion, and ends the exposure of the imaging device after the end time of the irradiation of the laser beam to the machining portion. The length of the delay time is the length of the time during which the laser beam irradiates while overlapping the machining portion.

[0007] A machining condition monitoring method according to an aspect of the present disclosure is a machining condition monitoring method that monitors the machining condition when machining a workpiece by irradiating a machining portion of the workpiece while scanning with a laser beam, using an imaging device that images the machining portion. When the laser beam irradiated to the machining portion scans while overlapping at least a part of the machining portion, a delay time is provided from the start time of the irradiation of the laser beam to the machining portion to start the exposure of the imaging device, and the exposure of the imaging device is ended after the end time of the irradiation of the laser beam to the machining portion. The length of the delay time is the length of the time during which the laser beam irradiates while overlapping the machining portion.

Advantages of the Invention

[0008] According to the present disclosure, it is possible to reduce the omission of monitoring the machining condition in laser machining.

Brief Description of the Drawings

[0009]

Figure 1A

Figure 1B

Figure 2A

Figure 2B

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Mode for Carrying Out the Invention

[0010] (Circumstances Leading to an Aspect of the Present Disclosure) Prior to specifically describing embodiments of the present disclosure, the circumstances leading to an aspect of the present disclosure will be described. The inventors of the present application have found that the following problems occur when monitoring the processing status in laser processing.

[0011] When monitoring the processing status in laser processing, an imaging device is used to image the processing location of the object to be processed using the light generated by the laser processing. At this time, when using a high-speed camera as in Patent Document 1 as the imaging device, there is a problem that the processing status of the location where the laser light is scanned during the non-exposure period generated between frames cannot be recorded. Therefore, during the non-exposure period, even if processing defects such as insufficient heating or excessive heating occur in the laser processing, it is impossible to record and determine the quality of the processing, and there is a risk of overlooking processing defects. In addition, when using a high-speed camera, the number of images to be captured increases, and the amount of data also increases.

[0012] For example, in the ITR (Integrate Then Read) mode, which is a readout mode in a general high-speed camera, since the exposure period and the readout period are alternately performed, the readout period becomes a non-exposure period, and the processing status of the location where the laser light is scanned during the non-exposure period cannot be recorded. FIG. 1A is a timing chart showing an example of the exposure and readout timings by a high-speed camera when imaging in the ITR mode. FIG. 1B is a diagram schematically showing the locations where light is detected when the operation of the timing chart of FIG. 1A is performed. In FIG. 1B, among the processing locations where the laser light is scanned, the locations where the light generated by the laser processing is not detected by the high-speed camera are surrounded by broken lines. As shown in FIGS. 1A and 1B, when imaging in the ITR mode, the light generated at the location where the laser light is scanned during the readout period within the frame period cannot be detected, and a period during which the processing status cannot be monitored occurs. In addition, a plurality of images are captured for one processing location.

[0013] Also, in a high-speed camera, even in the IWR (Integrate While Read) mode, which is a readout mode where reading is also performed during the exposure period, there is a non-exposure period between the exposure periods of two consecutive frames, and the processing status of the locations where the laser beam is scanned during the non-exposure period cannot be recorded. FIG. 2A is a timing chart showing an example of the exposure and readout timings by a high-speed camera when imaging in the IWR mode. FIG. 2B is a diagram schematically showing the locations where light is detected when the operation of the timing chart of FIG. 2A is performed. In FIG. 2B, the locations where the light generated by the laser processing is not detected by the high-speed camera among the processed locations where the laser beam is scanned are surrounded by broken lines. As shown in FIGS. 2A and 2B, even when imaging in the IWR mode, the light generated at the locations where the laser beam is scanned during the short time between the exposure periods of two consecutive frames cannot be detected, and there is a period during which the processing status cannot be monitored.

[0014] The present disclosure has been made in view of such problems, and an object thereof is to provide a processing status monitoring system and a processing status monitoring method capable of reducing the omission of monitoring the processing status in laser processing.

[0015] (Summary of the Present Disclosure) As an overview of the present disclosure, examples of the processing status monitoring system and the processing status monitoring method according to the present disclosure are shown below.

[0016] For example, the processing status monitoring system according to the first aspect of the present disclosure is a processing status monitoring system that monitors the processing status when processing the object to be processed by irradiating the processing location of the object to be processed while scanning a laser beam, and includes an imaging device that images the processing location and a control unit that controls the driving of the imaging device. When the laser beam irradiated on the processing location is scanned while overlapping at least a part of the processing location, the control unit provides a delay time from the start time of the irradiation of the laser beam on the processing location to start the exposure of the imaging device, and ends the exposure of the imaging device after the end time of the irradiation of the laser beam on the processing location. The length of the delay time is the length of the time during which the laser beam is irradiated while overlapping the processing location.

[0017] As a result, the imaging device starts the exposure with a delay from the start time of the irradiation of the laser beam by the time required for the overlapping scan of the laser beam, and continues the exposure until at least the end time of the irradiation of the laser beam. Therefore, during the irradiation of the laser beam on the processing location, the period from the start time of the irradiation of the laser beam to the time required for the overlapping scan becomes the period during which the exposure of the imaging device is not performed, and the exposure of the imaging device continues during the period in which the laser beam irradiated on the processing location makes one round of the processing location. As a result, light from the entire range of the processing location can be detected by one exposure of the imaging device. Therefore, in the processing status monitoring system according to the present aspect, it is possible to reduce the omission of monitoring the processing status in laser processing.

[0018] In addition, since the imaging device starts exposure with a delay of the time required for the overlapping scan of the laser beam from the start time of the irradiation of the laser beam, the light detected by the imaging device among the light from the overlapped portion during the laser processing is only the light when the laser beam passes through the overlapped portion last. Therefore, not only the portions other than the overlapped portion at the processing location but also the overlapped portion detect light corresponding to one irradiation of the laser beam by the imaging device. As a result, in the image when the laser processing is normally performed, the luminance value in the overlapped portion is almost the same as that of the portions other than the overlapped portion at the processing location. Thereby, it becomes possible to evaluate the processing status on the same basis as the portions other than the overlapped portion at the processing location also in the overlapped portion, and the evaluation can be easily performed. For example, even if the entire processing location is evaluated for the processing status on the same basis, it is possible to avoid an erroneous determination that uneven heating has occurred in the overlapped portion at the processing location.

[0019] Also, for example, the processing status monitoring system according to the second aspect of the present disclosure is the processing status monitoring system according to the first aspect, wherein the control unit ends the exposure of the imaging device with a delay of a predetermined time from the end time.

[0020] Thereby, since the light emitted from the processing location in the cooling process of the processing location after the irradiation of the laser beam can also be detected by the imaging device, more accurate monitoring of the processing status becomes possible.

[0021] Also, for example, the processing status monitoring system according to the third aspect of the present disclosure is the processing status monitoring system according to the second aspect, wherein the predetermined time is 1 second or less.

[0022] Thereby, since it is possible to suppress an increase in the exposure time of the imaging device after the irradiation of the laser beam ends, it is possible to suppress an increase in noise due to the generation of dark current.

[0023] Further, for example, the machining status monitoring system according to the fourth aspect of the present disclosure is a machining status monitoring system according to any one of the first to third aspects, and the imaging device images the machining location by detecting light in the wavelength range of the laser light.

[0024] Thereby, the machining status can be monitored using the reflected light of the laser light by the machining location.

[0025] Further, for example, the machining status monitoring system according to the fifth aspect of the present disclosure is a machining status monitoring system according to any one of the first to fourth aspects, and the imaging device images the machining location by detecting light in a wavelength range different from the wavelength range of the laser light.

[0026] Thereby, the machining status can be monitored using the thermal radiation or plasma emission generated when the machining location is irradiated with the laser light.

[0027] Further, for example, the machining status monitoring system according to the sixth aspect of the present disclosure is a machining status monitoring system according to any one of the first to fifth aspects. When the laser light irradiated on the machining location is scanned with overlap, the control unit provides the delay time from the start time of the irradiation of the laser light on the machining location to start the exposure of the imaging device, and ends the exposure of the imaging device after the end time of the irradiation of the laser light on the machining location. It has a first control mode, and a second control mode in which the exposure of the imaging device is started before the start time of the irradiation of the laser light on the machining location, and the exposure of the imaging device is ended after the end time of the irradiation of the laser light on the machining location.

[0028] Thereby, the exposure conditions of the imaging device can be flexibly changed according to the purpose of laser machining or the like.

[0029] Further, for example, the processing status monitoring system according to the seventh aspect of the present disclosure is a processing status monitoring system according to any one of the first to sixth aspects, and further includes a determination unit that determines whether the processing at the processing location is good or bad based on an image obtained by the imaging device capturing the processing location.

[0030] Thereby, it is possible to monitor the presence or absence of abnormalities in laser processing.

[0031] Further, for example, the processing status monitoring system according to the eighth aspect of the present disclosure is a processing status monitoring system according to the seventh aspect, and the determination unit determines whether the processing at the processing location is good or bad based on the luminance value of the image.

[0032] Thereby, it is possible to determine whether the processing is good or bad based on whether the light generated during laser processing is abnormal.

[0033] Further, for example, the processing status monitoring system according to the ninth aspect of the present disclosure is a processing status monitoring system according to the seventh aspect, and the imaging device captures the processing location by detecting infrared rays in two different wavelength ranges that are different from the wavelength range of the laser light. The determination unit determines whether the processing at the processing location is good or bad based on the ratio between the luminance value of the processing location in the image captured by detecting infrared rays in one of the two wavelength ranges and the luminance value of the processing location in the image captured by detecting infrared rays in the other of the two wavelength ranges.

[0034] Thereby, by utilizing the principle of the two-color method, it is possible to determine whether the processing is good or bad based on whether the temperature at the processing location is abnormal.

[0035] Also, for example, the processing status monitoring method according to the tenth aspect of the present disclosure monitors the processing status when processing the object to be processed by irradiating a laser beam while scanning the processing location of the object to be processed, using an imaging device that images the processing location. When the laser beam irradiated to the processing location overlaps and scans at least a part of the processing location, a delay time is provided from the start time of the irradiation of the laser beam to the processing location to start the exposure of the imaging device, and the exposure of the imaging device is ended after the end time of the irradiation of the laser beam to the processing location. The length of the delay time is the length of the time during which the laser beam is irradiated overlapping the processing location.

[0036] Thereby, similar to the processing status monitoring system according to the first aspect, it is possible to reduce the omission of monitoring the processing status in laser processing. Also, in the overlapping portion, it becomes possible to evaluate the processing status based on the same criteria as the portion other than the overlapping portion in the processing location, and the evaluation can be easily performed.

[0037] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that each of the embodiments described below shows comprehensive or specific examples. The numerical values, shapes, materials, components, arrangements and connection forms of the components, steps, order of steps, etc. shown in the following embodiments are examples and are not intended to limit the present disclosure. Various aspects described in this specification can be combined with each other as long as there is no contradiction. Also, among the components in the following embodiments, the components not described in the independent claims are described as optional components. In each figure, components having substantially the same function are denoted by common reference numerals, and redundant descriptions may be omitted or simplified.

[0038] In addition, the various elements shown in the drawings are merely schematically shown for the purpose of understanding the present disclosure, and dimensions, ratios, appearances, etc. may differ from the actual ones. That is, each figure is a schematic diagram and is not necessarily strictly illustrated. Therefore, for example, scales in each figure do not necessarily match.

[0039] Also, in this specification, terms indicating relationships between elements such as parallel or coincident, terms indicating the shapes of elements such as circular or rectangular, and numerical ranges are not expressions representing only strict meanings, but are expressions meaning substantially equivalent ranges, for example, including differences of about several percent.

[0040] In addition, in this specification, not only visible light but also invisible light such as ultraviolet rays and infrared rays are also referred to as "light" for convenience.

[0041] (Embodiment) [Configuration] First, the configuration of the processing status monitoring system according to the embodiment will be described.

[0042] FIG. 3 is a schematic diagram for explaining the processing status monitoring system 100 according to the present embodiment. FIG. 4 is a block diagram showing an example of the configuration of the processing status monitoring system 100 according to the present embodiment. In FIG. 3, the configurations other than the imaging device 10 in the processing status monitoring system 100 are not shown. Also, in FIG. 3, the imaging range of the imaging device 10 is indicated by a dashed line.

[0043] As shown in FIG. 3, the processing status monitoring system 100 is a system that monitors the processing status when processing the workpiece 110 by irradiating the processing location 111 of the workpiece 110 while scanning it with the laser beam L, using the imaging device 10. The processing status monitoring system 100 performs, for example, recording of the processing status and / or determination of the quality of the processing as monitoring of the processing status. The laser beam L is emitted from the laser processing machine 200 and scans the processing location 111 of the workpiece 110. The processing location 111 is the portion of the workpiece 110 that is processed by being irradiated with the laser beam L, and corresponds to the scanning range in one irradiation of the laser beam L.

[0044] In the example shown in FIG. 3, the workpiece 110 includes a transmissive member 112 through which the laser beam L passes and an absorptive member 113 that absorbs the laser beam L. The transmissive member 112 is disposed on the absorptive member 113. The transmissive member 112 and the absorptive member 113 are, for example, resin members. In the workpiece 110, the laser beam L that has passed through the transmissive member 112 is absorbed by the absorptive member 113, and the absorptive member 113 is heated by the laser beam L, whereby the transmissive member 112 and the absorptive member 113 are welded to each other. That is, when the laser beam L is irradiated to the processing location 111, the transmissive member 112 and the absorptive member 113 are welded at the processing location 111. Note that the workpiece 110 is not limited to an example in which it is composed of members that are welded to each other, and may be a single member. Also, even when two members are welded to each other, the two members may be welded by directly irradiating the interface of the two members with the laser beam L. Further, the shape and material of the workpiece 110 are not particularly limited. For example, the workpiece 110 may include a metal member.

[0045] The laser processing machine 200 performs welding, cutting, severing, cleaning, etc. of the object to be processed 110 with the laser beam L. The laser processing machine 200 includes, for example, a laser light source that emits the laser beam L and an optical system that guides the laser beam L as necessary. The laser processing machine 200 is, for example, a galvanoscanning type laser processing machine capable of scanning the laser beam L. The wavelength range of the laser beam L emitted by the laser light source is, for example, a wavelength range centered on a wavelength of 900 nm or more and 2500 nm or less, but is not particularly limited and is designed according to the purpose of laser processing. Note that the laser beam L irradiated on the object to be processed 110 may be scanned by moving the stage on which the object to be processed 110 is placed. In this case, the imaging device 10 also moves in synchronization with the object to be processed 110.

[0046] As shown in FIG. 4, the processing status monitoring system 100 includes an imaging device 10, a control unit 20, an input unit 30, an image acquisition unit 40, a determination unit 50, and a storage unit 60.

[0047] The imaging device 10 images the processing location 111 of the object to be processed 110. Specifically, the imaging device 10 images the processing location 111 by detecting the light generated by the laser processing at the processing location 111. Examples of the light generated by the laser processing include thermal radiation (infrared rays) and plasma emission (visible light) generated when the object to be processed 110 is irradiated with the laser beam L, and reflected light of the laser beam L by the object to be processed 110. The wavelength ranges of the thermal radiation and plasma emission generated when the object to be processed 110 is irradiated with the laser beam L are different from the wavelength range of the laser beam L. The imaging device 10 may detect light in the wavelength range of the laser beam L, or may detect light in a wavelength range different from the wavelength range of the laser beam L. Further, the imaging device 10 may detect light in two or more different wavelength ranges. The imaging device 10 is driven, for example, in a global shutter method in which the exposure period of all pixels is unified.

[0048] The imaging device 10 has, for example, one or more imaging elements that detect light, and an optical system that forms an image of light from a region including the processing location 111 on the imaging surface of the one or more imaging elements. The optical system may include a filter, a prism, or the like that restricts the wavelength range of the light detected by the one or more imaging elements. The wavelength range of the light detected by the imaging device 10 is determined by, for example, the sensitivity characteristics of the imaging element and the wavelength range of the light that is imaged on the imaging surface of the imaging element by the optical system. Further, the imaging device 10 substantially does not detect light in a wavelength range other than the wavelength range that is the detection target of the one or more imaging elements, for example, because the imaging device 10 does not have sensitivity to light in a wavelength range other than the wavelength range that is the detection target, or because light in a wavelength range other than the wavelength range that is the detection target does not enter the imaging surface due to the optical system.

[0049] The imaging element includes, for example, a photoelectric conversion element using single crystal silicon, black silicon having a fine structure formed on the surface of single crystal silicon, an InGaAs epitaxial thin film, quantum dots such as PbS or PbSe, or a semiconductor type carbon nanotube as a photoelectric conversion material.

[0050] Further, the imaging device 10 may be an imaging device for two-color method that captures an image capable of measuring temperature using the two-color method. In this case, the imaging device 10 captures the processed portion 111 by detecting infrared rays in two different wavelength ranges that are different from the wavelength range of the laser beam L. The two-color method is a method of detecting infrared rays due to thermal radiation from the same position in two different wavelength ranges and calculating the temperature from the ratio of the detection results in the two different wavelength ranges, that is, the luminance ratio. The imaging device for the two-color method, for example, disperses the light incident on the imaging device into infrared rays in two different wavelength ranges by a prism or the like. The imaging device for the two-color method, for example, forms images of infrared rays in two different wavelength ranges at different positions on the imaging surface of one imaging element. The imaging device for the two-color method may form images of infrared rays in two different wavelength ranges on the imaging surfaces of two different imaging elements. Specific examples of the imaging device for the two-color method include, for example, imaging devices disclosed in Patent Documents 2 to 4. Note that the imaging device for the two-color method is not limited to these examples and is not particularly limited. For example, as the imaging device for the two-color method, an imaging element in which two or more photoelectric conversion elements having different wavelength ranges with sensitivity are stacked may be used.

[0051] The control unit 20 controls the driving of the imaging device 10, specifically, the driving of the imaging element in the imaging device 10. The control unit 20 outputs, for example, a control signal to the imaging device 10. The control unit 20 controls, for example, the timing and time of exposure of the imaging device 10 based on the irradiation time of the laser beam L, the timing of the start of irradiation of the laser beam L, and the overlap time described later. The control unit 20 acquires, for example, a trigger regarding the irradiation start timing of the laser beam L, information regarding the irradiation time of the laser beam L, and information regarding the overlap time from the laser processing machine 200. The control unit 20 may acquire information regarding the irradiation time of the laser beam L and information regarding the overlap time input by the user to the input unit 30. Further, the control unit 20 may acquire information regarding the exposure time of the imaging device 10 input by the user to the input unit 30. Details of the control of the imaging device 10 by the control unit 20 will be described later.

[0052] The input unit 30 is an interface that receives input from the user. The input unit 30 is composed of, for example, an input device such as a touch panel or input buttons. Further, the input unit 30 may be composed of a communication circuit that receives the user's input to an external device such as a personal computer or an information terminal by communicating with the external device.

[0053] The input unit 30 receives, for example, input of information regarding the laser processing conditions by the laser processing machine 200, such as information regarding the irradiation time and overlap time of the laser beam L by the laser processing machine 200 from the user. As information regarding the irradiation time and overlap time of the laser beam L, for example, not only information directly indicating the irradiation time and overlap time of the laser beam L, but also information for calculating the irradiation time and overlap time of the laser beam L, such as the scanning speed, scanning distance, circumferential distance described later, and overlap length described later, in the irradiation of the laser beam L may be included. The input from the user received by the input unit 30 may be stored in the storage unit 60. Note that the processing status monitoring system 100 may not include the input unit 30.

[0054] The image acquisition unit 40 acquires the image captured by the imaging device 10 of the processing location 111. The image acquisition unit 40 stores, for example, the acquired image in the storage unit 60. The image acquired by the image acquisition unit 40 includes, for example, luminance values as pixel values. Further, when the imaging device 10 is an imaging device for the two-color method, the image acquisition unit 40 may calculate the temperature based on the ratio of the luminance values at corresponding positions of the two images for measuring the temperature, and generate an image including the calculated temperature value as a pixel value. Further, the image acquisition unit 40 may store the generated image in the storage unit 60. Further, the image acquisition unit 40 may perform image processing on the image captured by the imaging device 10 and then output the image after the image processing to the determination unit 50. Further, the image acquisition unit 40 may store the image after the image processing in the storage unit 60.

[0055] The determination unit 50 determines whether the processing of the processing location 111 is good or bad based on the image obtained by imaging the processing location 111. The determination unit 50 outputs the determination result to the outside, for example. The determination result output by the determination unit 50 is obtained by an external display, for example, and the determination result is displayed on the display. Further, the determination unit 50 may output a determination result indicating that the processing is defective to an external alarm, and the alarm that has obtained the determination result may output an alarm. Further, the determination unit 50 may store the determination result in the storage unit 60. Further, when storing the determination result in the storage unit 60, the determination unit 50 may store the determination result in association with the image used for the determination.

[0056] The control unit 20, the image acquisition unit 40, and the determination unit 50 are processing circuits, and are realized by a microcomputer or a processor including a memory in which a program for performing the above-described and hereinafter-described processing is stored. In this case, the control unit 20, the image acquisition unit 40, and the determination unit 50 may be realized by individual microcomputers or processors, etc., or two or more of these functions may be realized by one microcomputer or processor, etc. The program may be stored in the storage unit 60. Further, at least one of the control unit 20, the image acquisition unit 40, and the determination unit 50 may be realized by a dedicated logic circuit that performs the above-described and hereinafter-described processing.

[0057] The storage unit 60 is a storage device for storing the monitoring results by the processing status monitoring system 100. Data used by the control unit 20 and the determination unit 50 may be stored in the storage unit 60. The storage unit 60 is, for example, a semiconductor memory or an HDD (Hard Disk Drive), etc.

[0058] [Operation example of the imaging device] Next, an operation example regarding the driving of the imaging device 10 in the processing status monitoring system 100 will be described. In each operation example described below, an example of the operation of the imaging device 10 when the laser beam L irradiated to the processing location 111 scans at least a part of the processing location 111 in an overlapping manner will be described.

[0059] FIG. 5 is a diagram for explaining an example of the scanning path of the laser beam L. FIG. 5 shows a top view when the laser beam L is irradiated to the processing location 111 on the object to be processed 110. In the example shown in FIG. 5, the processing location 111 is annular. That is, the laser beam L irradiated to the processing location 111 is scanned so as to circulate annularly. The annular shape of the processing location 111 may be a rectangle as shown in the figure, or may be a polygon other than a rectangle, a circle, an ellipse, or a shape combining at least one of a straight line and a curve.

[0060] As shown in FIG. 5, the laser beam L irradiated to the processing location 111 is scanned so as to circulate annularly from the starting point of the scan and return to the position of the starting point, and then scanned while overlapping a predetermined range from the position of the starting point. The scanning of the laser beam L irradiated to the processing location 111 ends while overlapping at least a part of the processing location 111. In the portion where the laser beam L is scanned overlappingly at the processing location 111, the laser beam L passes through two or more times. Since the vicinity of the starting point of the scanning of the laser beam L is irradiated with the laser beam L immediately after the start of irradiation of the laser beam L to the processing location 111, the temperature may not easily rise. However, due to the overlap, the vicinity of the starting point of the scan is heated again, so that the quality of the processing can be improved. For example, the welding strength between the transmission member 112 and the absorption member 113 can be increased by the overlap.

[0061] As shown in FIG. 5, the processing location 111 includes an overlap portion 115 where the laser beam L is scanned overlappingly. In the example shown in FIG. 5, the laser beam L irradiated to the processing location 111 is scanned overlappingly from the position of the starting point to the position of the end point after making one round of the processing location 111 annularly. Therefore, the portion from the position of the starting point to the position of the end point of the scanning of the laser beam L at the processing location 111 is the overlap portion 115. Note that the laser beam L irradiated to the processing location 111 may be scanned so as to make a plurality of rounds around the processing location 111. In this case, since the laser beam L irradiated to the processing location 111 passes through the entire processing location 111 two or more times, the entire processing location 111 becomes the overlap portion.

[0062] (1) Operation Example 1 First, the operation example 1 of the imaging device 10 will be described. In operation example 1, an example of the operation of the imaging device 10 when the laser beam L irradiated on the processing location 111 as shown in FIG. 5 overlaps and scans from the starting point position to the ending point position after making one circular round will be described.

[0063] FIG. 6 is a timing chart of the operation example 1 of the imaging device 10 according to the present embodiment. In the "Laser Beam Irradiation" of FIG. 6, the irradiation timing of the laser beam L is shown. In the "Laser Beam Irradiation" of FIG. 6, the laser beam L is emitted by the laser processing machine 200 during the period when the chart is at a high level. In the "Exposure" of FIG. 6, the timing at which the imaging device 10 performs exposure is shown. In the "Exposure" of FIG. 6, the exposure of the imaging device 10 is performed during the period when the chart is at a high level. In the "Reading" of FIG. 6, the timing at which the imaging device 10 reads the signal obtained by the exposure is shown. In the "Reading" of FIG. 6, the reading of the imaging device 10 is performed during the period when the chart is at a high level. Note that the matters indicated by "Laser Beam Irradiation", "Exposure", and "Reading" are the same as those in FIG. 6 in the figures of other timing charts.

[0064] As shown in FIG. 6, the laser processing machine 200 starts irradiating the laser beam L on the processing location 111, and irradiates the laser beam L while scanning the processing location 111 for the irradiation time TL from the start of the irradiation of the laser beam L. The irradiation time TL is, for example, 100 milliseconds or more, but is not particularly limited. The irradiation time TL may be 200 milliseconds or more. Also, the irradiation time TL may be 10 seconds or less.

[0065] After the start of the irradiation of the laser beam L, the control unit 20 starts the exposure of the imaging device 10 by providing a delay time that is the same as the overlap time, i.e., time t1, from the start time of the irradiation of the laser beam L to the processing location 111. Therefore, the imaging device 10 starts the exposure with a delay of time t1 from the start time of the irradiation of the laser beam L to the processing location 111. The overlap time is the time required when the laser beam L scans while overlapping the overlap portion 115. That is, the length of the delay time is the length of the time during which the laser beam L irradiates while overlapping the processing location 111. The imaging device 10 starts the exposure when the laser beam L irradiated to the processing location 111 reaches the position that is the end point of the scan. The control unit 20, for example, acquires a trigger indicating the timing of the start of the irradiation of the laser beam L from the laser processing machine 200, and based on the trigger, starts the exposure of the imaging device 10 with a delay of the delay time from the timing of the start of the irradiation of the laser beam L.

[0066] The control unit 20, for example, acquires information regarding the overlap time from the input unit 30 or the laser processing machine 200, and determines the delay time to be the same length as the overlap time based on the acquired information regarding the overlap time. The information regarding the overlap time includes, for example, the overlap length, which is the length of the overlap portion 115, and the scanning speed of the laser beam L. In this case, the control unit 20 determines the delay time by dividing the overlap length by the scanning speed of the laser beam L. Further, the information regarding the overlap time may include the circumferential distance, which is the length of one round of the processing location 111, the scanning distance of the laser beam L, and the scanning speed of the laser beam L. In this case, the control unit 20 determines the delay time by dividing the length obtained by subtracting the circumferential distance from the scanning distance of the laser beam L by the scanning speed of the laser beam L. The control unit 20 may determine the delay time before the start of the irradiation of the laser beam L to the processing location 111, or may determine the delay time during the irradiation of the laser beam L to the processing location 111.

[0067] Next, the control unit 20 ends the exposure of the imaging device 10 at the end time of the irradiation of the laser beam L.

[0068] The control unit 20 determines, for example, the exposure time by subtracting the above delay time from the irradiation time TL, and ends the exposure of the imaging device 10 after the exposure time has elapsed since the start of the exposure of the imaging device 10. The control unit 20 acquires information regarding the irradiation time TL from, for example, the input unit 30 or the laser processing machine 200. The information regarding the irradiation time TL includes, for example, the scanning speed and the scanning distance of the laser beam L. In this case, the control unit 20 determines the irradiation time TL by dividing the scanning distance of the laser beam L by the scanning speed of the laser beam L. The information regarding the irradiation time TL may include the overlap length and the circumferential distance instead of the scanning distance of the laser beam L. In this case, the control unit 20 calculates the scanning distance of the laser beam L by adding the overlap length and the circumferential distance. Further, the control unit 20 may directly determine the exposure time without subtracting the delay time from the irradiation time TL by dividing the above circumferential distance by the scanning speed of the laser beam L. The control unit 20 may determine the exposure time before the start of the exposure of the imaging device 10, or may determine the exposure time during the exposure of the imaging device 10.

[0069] Next, after the exposure ends, the imaging device 10 reads out the signal obtained by the exposure. Based on the read signal, the imaging device 10 generates an image of the processing location 111 and outputs the generated image to the image acquisition unit 40.

[0070] FIG. 7 is a schematic diagram showing an example of the image 15 generated by the imaging device 10 in Operation Example 1. In FIG. 7, the image 15 in the case where laser processing is normally performed is shown. Further, the image 15 is an image obtained by the imaging device 10 imaging the processing location 111 by detecting the thermal radiation from the processing location 111. Note that even when the imaging device 10 images the processing location 111 by detecting light from the processing location 111 other than thermal radiation, an image 15 as shown in FIG. 7 is captured. Further, in the image 15 of FIG. 7, a portion with a higher luminance value (that is, the thermal radiation intensity in the image 15) is shown with a darker color. That is, in FIG. 7, an image with the black and white reversed from the actual image is shown. The same applies to the figures showing the images captured by the imaging device 10 described hereinafter, in that the black and white are reversed from the actual image.

[0071] In Operation Example 1, the imaging device 10 starts exposure with a delay time of the same time t1 as the overlap time from the start time of irradiation of the laser beam L, and continues the exposure until the end time of irradiation of the laser beam L. Therefore, during the irradiation of the laser beam L to the processing location 111, the period of the same delay time as the overlap time from the start time of irradiation of the laser beam L is a period during which the exposure of the imaging device 10 is not performed. Thus, as also shown in FIG. 6, during the period in which the laser beam L irradiated to the processing location 111 makes one round around the processing location 111 starting from the position of the end point of the scanning of the laser beam L, the exposure of the imaging device 10 continues. As a result, as shown in FIG. 7, in the image 15, light from the entire range of the processing location 111 scanned in a ring shape by the laser beam L is detected. In this way, in Operation Example 1, since light from the entire range of the processing location 111 can be detected by one exposure of the imaging device 10, it is possible to reduce the omission in monitoring the processing status in laser processing. Further, since the processing status of the entire range of the processing location 111 can be monitored in one image 15, it is possible to reduce the amount of data for monitoring laser processing, and it is also possible to record and manage the processing status and the processed product in a one-to-one correspondence.

[0072] Also, in Operation Example 1, since the imaging device 10 starts exposure with a delay time of the same time t1 as the overlap time from the start time of the irradiation of the laser beam L, when the laser beam L passes through the overlap portion 115 for the first time immediately after the start of the irradiation of the laser beam L, the imaging device 10 has not started exposure. Therefore, the light detected by the imaging device 10 among the light from the overlap portion 115 during the laser processing is only the light when the laser beam L passes through the overlap portion 115 for the last time. Thus, not only the portions other than the overlap portion 115 at the processing location 111 but also the overlap portion 115 detect light corresponding to one irradiation of the laser beam L by the imaging device 10. As a result, in the image 15 when the laser processing is normally performed, the overlap portion 115 also has a luminance value almost equal to that of the portions other than the overlap portion 115 at the processing location 111. Thereby, it becomes possible to evaluate the processing status at the overlap portion 115 on the same basis as the portions other than the overlap portion 115 at the processing location 111, and the evaluation can be easily performed. For example, even if the entire processing location 111 is evaluated for the processing status on the same basis, it is possible to avoid an incorrect determination that heat unevenness has occurred in the overlap portion 115 at the processing location 111.

[0073] Further, when the processing location 111 has the overlap portion 115, it is important whether the temperature of the overlap portion 115 has reached the target temperature when the laser beam L passes through the overlap portion 115 for the last time. In Operation Example 1, since the imaging device 10 ends exposure at the end time of the irradiation of the laser beam L, it is possible to monitor the processing status when the laser beam L passes through the overlap portion 115 for the last time. Also, if an abnormality in temperature occurs when the laser beam L passes through the overlap portion 115 for the first time, it may be reflected in the image of the processing location 111 when the laser beam L passes through the overlap portion 115 for the last time. Therefore, it becomes possible to indirectly monitor the processing status when the laser beam L passes through the overlap portion 115 for the first time.

[0074] In the example shown in FIG. 6, the laser beam L emitted from the laser processing machine 200 was continuous light in which the emission continued from the start of irradiation of the laser beam L to the end of irradiation, that is, light by a CW (Continuous Wave) laser. However, the laser beam L may be pulsed light that repeats at a predetermined frequency, that is, light by a pulsed laser. FIG. 8 is a timing chart for explaining the irradiation time TL of the laser beam L in the pulsed laser.

[0075] As shown in FIG. 8, in the case of the laser beam L by the pulsed laser, the irradiation time TL of the laser beam L is the time during which pulsed light is intermittently and repeatedly irradiated. That is, in the case of the laser beam L by the pulsed laser, the end of irradiation of the laser beam L is not the end of each pulsed light, but the end of the repetition of the pulsed light. Therefore, the imaging device 10 ends the exposure at the end time of the repetition of the pulsed light after the irradiation time TL has elapsed from the start of the repetition of the pulsed light. Also, even in the example shown in FIG. 8, the irradiation time TL and the overlap time of the laser beam L can be determined by the method described above.

[0076] (2) Operation Example 2 Next, operation example 2 of the imaging device 10 will be described. In the following description of operation example 2, the differences from operation example 1 will be mainly described, and the description of the common points will be omitted or simplified. In operation example 2, an example different from operation example 1 of the operation of the imaging device 10 when the laser beam L irradiated to the processing location 111 as shown in FIG. 5 is scanned while overlapping from the starting point position to the ending point position after making one round in a ring shape will be described.

[0077] FIG. 9 is a timing chart of operation example 2 of the imaging device 10 according to the present embodiment.

[0078] As shown in FIG. 9, the laser processing machine 200 starts irradiating the laser beam L to the processing location 111, and irradiates the processing location 111 while scanning the laser beam L for the irradiation time TL from the start of irradiation of the laser beam L.

[0079] After the start of the irradiation of the laser beam L, the control unit 20 starts the exposure of the imaging device 10 after providing a delay time that is the same as the overlap time, i.e., time t1, from the start time of the irradiation of the laser beam L to the processing location 111. The operation in operation example 2 up to this point is the same as the above operation example 1.

[0080] Next, the control unit 20 ends the exposure of the imaging device 10 with a delay of a predetermined time Δt from the end time of the irradiation of the laser beam L.

[0081] The control unit 20 determines, for example, the exposure time as the time obtained by subtracting the above delay time from the irradiation time TL and further adding a predetermined time Δt, and ends the exposure of the imaging device 10 after the exposure time has elapsed since the start of the exposure of the imaging device 10. The method by which the control unit 20 determines the irradiation time TL and the delay time is as described in operation example 1. The control unit 20 may determine the exposure time before the start of the exposure of the imaging device 10, or may determine the exposure time during the exposure of the imaging device 10.

[0082] Next, after the exposure ends, the imaging device 10 reads out the signal obtained by the exposure. Based on the read signal, the imaging device 10 generates an image of the processing location 111 and outputs the generated image to the image acquisition unit 40. Also in operation example 2, when the laser processing is performed normally, an image 15 as shown in FIG. 7 is obtained.

[0083] Also, in the image 15 obtained in operation example 2, the processing status near the end point of the scanning of the laser beam L can be monitored more accurately. This is because the imaging device 10 ends the exposure with a delay of a predetermined time Δt from the end time of the irradiation of the laser beam L. The reason for this will be described with reference to FIG. 10.

[0084] FIG. 10 is a diagram schematically showing the temporal change in the thermal radiation intensity at the start and end points of the scanning of the laser beam L at the processing location 111. As shown in FIG. 10, at any location in the processing location 111, when the scanned laser beam L reaches, the temperature rises rapidly, so the thermal radiation intensity also rises rapidly. Then, since the laser beam L passes by, the thermal radiation intensity decreases over a predetermined time. As shown in FIG. 10, at the start point of the scanning of the laser beam L, since the laser beam L is scanned to other locations even after the second arrival of the laser beam L, the irradiation of the laser beam L on the processing location 111 continues. On the other hand, at the end point of the scanning of the laser beam L, the irradiation of the laser beam L on the processing location 111 ends immediately after the second arrival of the laser beam L. Therefore, when the imaging device 10 finishes exposure at the same time as the time when the irradiation of the laser beam L on the processing location 111 ends, at the end point of the scanning of the laser beam L, the thermal radiation during the process in which the thermal radiation intensity decreases over a predetermined time after the second arrival of the laser beam L is not detected by the imaging device 10. That is, the amount of the signal when the imaging device 10 detects the light from the end point of the scanning of the laser beam L when the second arrival of the laser beam L occurs is less than that of other parts of the processing location 111. In contrast, in the operation example 2 shown in FIG. 10, since the imaging device 10 finishes exposure with a delay of a predetermined time Δt from the end time of the irradiation of the laser beam L, the thermal radiation during the process in which the thermal radiation intensity decreases over a predetermined time at the end point of the scanning of the laser beam L when the second arrival of the laser beam L occurs can also be detected. Therefore, at the end point of the scanning of the laser beam L as well, the thermal radiation is detected by the imaging device 10 under the same conditions as other parts such as the start point of the scanning of the laser beam L, and more accurate monitoring of the processing situation becomes possible.

[0085] The predetermined time Δt is, for example, 1 second or less. This ensures the time for exposing the decreasing thermal radiation at the end point of the scanning of the laser beam L, suppresses the increase in the exposure time of the imaging device 10 after the irradiation of the laser beam L ends, and can suppress the increase in noise due to the generation of dark current. The predetermined time Δt may be 100 milliseconds or less. The upper limit value of the predetermined time Δt depends on the characteristics of the imaging element used in the imaging device 10, and is the time under the condition that the noise charge amount due to dark current is less than the saturation charge amount of each pixel. Dark current has temperature dependence, and the higher the temperature of the imaging element, the greater the dark current per unit time, so the upper limit value of the settable predetermined time Δt becomes smaller. Although it is possible to suppress saturation due to dark current and extend the exposure time by cooling the imaging element with a Peltier element or the like, when capturing instantaneous light emission phenomena such as thermal radiation in laser scanning processing, an unnecessarily long exposure time does not lead to an increase in the signal amount, but rather causes a decrease in S / N due to dark current shot noise. Therefore, the upper limit value of the predetermined time Δt may be set to the longest time at which saturation of the charge amount of each pixel does not occur and the S / N exceeds 0 dB when the signal charge amount in the processing situation to be monitored is given. Also, the lower limit value of the predetermined time Δt is not particularly limited because the rate of decrease of thermal radiation varies depending on the processing conditions and the material of the processing location 111, but is, for example, 10 milliseconds or more, and may be 30 milliseconds or more. The predetermined time Δt is set, for example, by previously measuring the time for the thermal radiation to decrease after the irradiation of the laser beam L and based on the measurement result. After the time when the thermal radiation becomes below the detection lower limit in the imaging device 10, only the noise due to dark current increases, so the predetermined time Δt is set, for example, to the time from the end of the irradiation of the laser beam L until the thermal radiation becomes below the detection lower limit. Also, the control unit 20 may acquire information indicating the material of the processing location 111 via the input unit 30 and determine the predetermined time Δt based on the material of the processing location 111. For example, when the material of the processing location 111 is resin, the control unit 20 determines the predetermined time Δt to be longer than when the material of the processing location 111 is metal.

[0086] (3) Operation Example 3 Next, an operation example 3 of the imaging device 10 will be described. In the following description of operation example 3, the differences from operation examples 1 and 2 will be mainly described, and the description of the common points will be omitted or simplified. In operation example 3, an example different from operation examples 1 and 2 of the operation of the imaging device 10 when the laser beam L irradiated to the processing portion 111 as shown in FIG. 5 scans in an overlapping manner from the starting point position to the ending point position after making one round in a ring shape will be described.

[0087] FIG. 11 is a timing chart of operation example 3 of the imaging device 10 according to the present embodiment.

[0088] As shown in FIG. 11, the control unit 20 starts the exposure of the imaging device 10 at the start time of the irradiation of the laser beam L to the processing portion 111. For example, the control unit 20 acquires a trigger indicating the timing of the start of the irradiation of the laser beam L to the processing portion 111 from the laser processing machine 200, and based on the trigger, starts the exposure of the imaging device 10 in synchronization with the start of the irradiation of the laser beam L.

[0089] The laser processing machine 200, for example, starts scanning simultaneously with the start of the irradiation of the laser beam L to the processing portion 111, and irradiates the processing portion 111 while scanning the laser beam L for an irradiation time TL from the start of the irradiation of the laser beam L.

[0090] Next, the control unit 20 ends the exposure of the imaging device 10 with a delay of a predetermined time Δt from the end time of the irradiation of the laser beam L. For example, the control unit 20 determines the exposure time as the time obtained by adding the predetermined time Δt to the irradiation time TL, and ends the exposure of the imaging device 10 after the exposure time has elapsed from the start of the exposure of the imaging device 10. The method by which the control unit 20 determines the irradiation time TL is as described in operation example 1. The control unit 20 may determine the exposure time before the start of the exposure of the imaging device 10, or may determine the exposure time during the exposure of the imaging device 10. Note that the control unit 20 may end the exposure of the imaging device 10 at the end time of the irradiation of the laser beam L as in operation example 1.

[0091] Next, after the exposure is completed, the imaging device 10 reads out the signal obtained by the exposure. Based on the read signal, the imaging device 10 generates an image of the processing location 111 and outputs the generated image to the image acquisition unit 40.

[0092] FIG. 12 is a schematic diagram showing an example of the image 16 generated by the imaging device 10 in operation example 3. In FIG. 12, the image 16 in the case where the laser processing is normally performed is shown. Further, the image 16 is an image obtained by the imaging device 10 imaging the processing location 111 by detecting the thermal radiation from the processing location 111.

[0093] In operation example 3, the exposure of the imaging device 10 starts in synchronization with the start of the irradiation of the laser beam L. Therefore, the light from the overlap portion 115 when the laser beam L is irradiated for the first time to the overlap portion 115 and the light from the overlap portion 115 when the laser beam L is irradiated for the second time to the overlap portion 115 are integrated and detected. As a result, as shown in FIG. 12, in the image 16, the luminance value of the overlap portion 115 becomes higher than the luminance value of the portion other than the overlap portion 115 in the processing location 111. Thereby, in the image 16 in which the processing location 111 is imaged, the overlap portion 115 can be recognized. For example, using the image 16, it is possible to evaluate whether or not the laser beam L is normally overlapped and irradiated to the overlap portion 115.

[0094] (4) Operation example 4 Next, an operation example 4 of the imaging device 10 will be described. In the following description of operation example 4, the differences from operation examples 1 to 3 will be mainly described, and the description of the common points will be omitted or simplified. In operation example 4, an example of the operation when the laser beam L irradiated on the processing location 111 is scanned so as to circle around the processing location 111 a plurality of times will be described. When the laser beam L irradiated on the processing location 111 is scanned so as to circle around the processing location 111 a plurality of times, the temperature of the processing location 111 increases as the number of circles increases. Thereby, the welding strength between the transmissive member 112 and the absorptive member 113 in the processing object 110 can be enhanced. In particular, when the processing object 110 is large, if it is processed by irradiating the laser beam L once, the time difference in the timing at which the laser beam L is irradiated between the start point and the end point of the scanning becomes large, and mechanical distortion is likely to occur in the processing object 110. In such a case, by increasing the scanning speed of the laser beam L and irradiating the same processing location 111 with the laser beam a plurality of times, although the heat input per circle decreases, the entire processing location 111 can be gradually heated almost simultaneously, which may be effective for obtaining a good processing result.

[0095] Also, in the following description of operation example 4, the case where the position of the start point and the position of the end point of the scanning of the laser beam L are different as shown in FIG. 5 will be described. Specifically, the irradiated laser beam L at the processing location 111 starts scanning from the start point of the scanning, circles around a plurality of times starting from the start point of the scanning, and then is scanned to the end point of the scanning. Note that in operation example 4, the position of the start point and the position of the end point of the scanning of the laser beam L may be the same.

[0096] FIG. 13 is a timing chart of operation example 4 of the imaging device 10 according to the present embodiment.

[0097] As shown in FIG. 13, the laser processing machine 200 starts irradiating the laser beam L on the processing location 111, and irradiates the laser beam L while scanning the processing location 111 for an irradiation time TL from the start of the irradiation of the laser beam L.

[0098] After the start of irradiation of the laser beam L, the control unit 20 starts the exposure of the imaging device 10 after providing a delay time that is the same as the overlap time, i.e., time t1, from the start time of irradiation of the laser beam L to the processing location 111. In operation example 4, the overlap time is the time required for the laser beam L irradiated to the processing location 111 to scan the processing location 111 after the second round and subsequent rounds. The imaging device 10 starts exposure when the laser beam L irradiated to the processing location 111 reaches the position that is the end point of the scan at the time of the previous round before the last round. The control unit 20, for example, acquires a trigger indicating the timing of the start of irradiation of the laser beam L from the laser processing machine 200, and starts the exposure of the imaging device 10 after delaying by the delay time from the timing of the start of irradiation of the laser beam L.

[0099] The control unit 20, for example, acquires information regarding the overlap time from the input unit 30 or the laser processing machine 200, and determines the delay time to be the same length as the overlap time based on the acquired information regarding the overlap time. The information regarding the overlap time includes, for example, the length of the overlap portion 115, the number of times the laser beam L orbits the processing location 111, the orbital distance, and the scanning speed of the laser beam L. When the length of the overlap portion 115 is L1, the number of times the laser beam L orbits the processing location 111 is N, the orbital distance is L2, and the scanning speed of the laser beam L is V, the control unit 20 determines the time calculated as {L1+(N - 1)×L2} / V as the delay time. Also, the information regarding the overlap time may include the orbital distance, the scanning distance of the laser beam L, and the scanning speed of the laser beam L. In this case, the delay time is determined by dividing the length obtained by subtracting the orbital distance from the scanning distance of the laser beam L by the scanning speed of the laser beam L. The control unit 20 may determine the delay time before the start of irradiation of the laser beam L to the processing location 111, or may determine the delay time during the irradiation of the laser beam L to the processing location 111.

[0100] Next, the control unit 20 ends the exposure of the imaging device 10 with a delay of a predetermined time Δt from the end time of the irradiation of the laser beam L. For example, the control unit 20 determines the exposure time as the time obtained by subtracting the above-described delay time from the irradiation time TL and further adding a predetermined time Δt, and ends the exposure of the imaging device 10 after the exposure time has elapsed from the start of the exposure of the imaging device 10. For example, the control unit 20 acquires information regarding the irradiation time TL from the input unit 30 or the laser processing machine 200. The information regarding the irradiation time TL includes, for example, the scanning speed and the scanning distance of the laser beam L. In this case, the control unit 20 determines the irradiation time TL by dividing the scanning distance of the laser beam L by the scanning speed of the laser beam L. The information regarding the irradiation time TL may include, instead of the scanning distance of the laser beam L, the overlap length, the circumferential distance, and the number of times the laser beam L orbits the processing location 111. In this case, the control unit 20 calculates the scanning distance of the laser beam L by adding the distance obtained by multiplying the overlap length by the circumferential distance by the number of times. Further, the control unit 20 may directly determine the exposure time without subtracting the delay time from the irradiation time TL by dividing the circumferential distance by the scanning speed of the laser beam L. The control unit 20 may determine the exposure time before the start of the exposure of the imaging device 10, or may determine the exposure time during the exposure of the imaging device 10. Note that the control unit 20 may end the exposure of the imaging device 10 at the end time of the irradiation of the laser beam L as in the operation example 1.

[0101] Next, after the exposure ends, the imaging device 10 reads out the signal obtained by the exposure. Based on the read signal, the imaging device 10 generates an image of the processing location 111 and outputs the generated image to the image acquisition unit 40. Thereby, an image in which the light from the processing location 111 corresponding to only the last one orbit of the laser beam L is detected is obtained. For example, also in the operation example 4, when the laser processing is normally performed, an image 15 as shown in FIG. 7 is obtained.

[0102] Also, if an abnormal temperature occurs during the scanning of the laser beam L in a circumference other than the last circumference, it may also be reflected in the image of the processing location 111 during the scanning of the laser beam L in the last circumference. Therefore, by obtaining an image in which the light from the processing location 111 in the scanning of only the last circumference of the laser beam L with respect to the processing location 111 is detected, the processing status in the scanning of the laser beam L in the circumferences other than the last circumference can also be indirectly monitored.

[0103] [Operation of the Processing Status Monitoring System] Next, an example of the operation of the processing status monitoring system 100 will be described. FIG. 14 is a flowchart showing an example of the operation of the processing status monitoring system 100 according to the present embodiment. Hereinafter, the example of the operation of the processing status monitoring system 100 when the imaging device 10 performs the operation of the above-described operation example 1 or 2 will be mainly described.

[0104] As shown in FIG. 14, first, the control unit 20 starts the exposure of the imaging device 10 after delaying it by a delay time having the same length as the overlap time from the start time of the irradiation of the laser beam L with respect to the processing location 111 (step S11). That is, the control unit 20 starts the exposure of the imaging device 10 after providing a delay time from the start time of the irradiation of the laser beam L with respect to the processing location 111. Next, the control unit 20 ends the exposure of the imaging device 10 started in step S11 after the end time of the irradiation of the laser beam L with respect to the processing location 111 when the irradiation time TL has elapsed from the start time of the irradiation of the laser beam L (step S12). The imaging device 10 outputs, for example, an image of the processing location 111 captured by the exposure from step S11 to step S12 to the image acquisition unit 40. The image acquisition unit 40 acquires the image output from the imaging device 10 and stores the acquired image in the storage unit 60.

[0105] The details of the operation of the processing status monitoring system 100 in steps S11 and S12 are as described in the above operation example 1 or 2 of the imaging device 10.

[0106] Next, the determination unit 50 determines whether the processing of the processing location 111 is good or not based on the image captured by the imaging device 10 (step S13). The determination unit 50 outputs the determination result. The determination unit 50 acquires, for example, the image in which the processing location 111 is captured from the image acquisition unit 40, but it may also be acquired directly from the imaging device 10. The determination unit 50, for example, extracts the contour of the location where the processing location 111 appears from the image in which the processing location 111 is captured, and uses the location within the extracted contour for the determination.

[0107] The determination unit 50 determines whether the processing of the processing location 111 is good or not based on, for example, the luminance value of the image in which the processing location 111 is captured. The determination unit 50 determines that, for example, in the image, if the luminance values in the range above a certain standard at the processing location 111 are within a predetermined range, it is determined to be good. For example, when the imaging device 10 detects the thermal radiation generated by irradiating the processing object 110 with the laser beam L, it can be said that the processing location 111 has been heated to an appropriate temperature if the luminance value of the processing location 111 in the image is within a predetermined range. Also, for example, when the imaging device 10 detects the reflected light of the laser beam L by the processing object 110, it can be said that the processing location 111 has been irradiated with the laser beam L of appropriate energy if the luminance value of the processing location 111 is within a predetermined range. Also, when foreign matter adheres to the processing location 111, etc., the reflected light from the processing location 111 increases or decreases, so an abnormality can be detected based on the luminance value of the location where the processing location 111 appears.

[0108] Also, the determination unit 50 may determine whether the processing of the processing location 111 is good or not based on the width of the processing location 111 in the image in which the processing location 111 is captured. The determination unit 50 determines that, for example, in the image, if the width of the processing location 111 is within a predetermined range, it is determined to be good.

[0109] Also, when the imaging device 10 is an imaging device for the two-color method, the determination unit 50 determines, for example, based on the ratio between the luminance value of the processing location 111 when imaging is performed by detecting infrared rays in one of the two wavelength ranges and the luminance value of the processing location 111 when imaging is performed by detecting infrared rays in the other of the two wavelength ranges, whether the processing of the processing location 111 is good or not. The determination unit 50 may use the ratio of the luminance values directly for determination, or may use the temperature calculated according to the principle of the two-color method based on the ratio of the luminance values for determination. The determination unit 50 determines, for example, that it is good if the ratio of the luminance values of the processing location 111 or the calculated temperature within a range above a certain standard at the processing location 111 is within a predetermined range.

[0110] In addition, in steps S11 and S12, instead of the operations described in the above operation examples 1 or 2 of the imaging device 10, the operations described in operation examples 3 or 4 of the imaging device 10 may be performed. The control unit 20 has, for example, a plurality of control modes for causing the imaging device 10 to perform at least two of the operations from operation examples 1 to 4, and selects one control mode from the plurality of control modes based on a user's selection instruction of the control mode to the input unit 30 or information regarding processing conditions from the laser processing machine 200 or the like. Thereby, the exposure conditions of the imaging device 10 can be flexibly changed according to the purpose of laser processing or the like. The control mode for causing the imaging device 10 to perform the operation of operation example 1, 2, or 4 is an example of the first control mode, and the control mode for causing the imaging device 10 to perform the operation of operation example 3 is an example of the second control mode. In the control mode for causing the imaging device 10 to perform the operation of operation example 3, in step S11, instead of the process shown in FIG. 14, the control unit 20 starts the exposure of the imaging device 10 before the start time of the irradiation of the laser beam L to the processing location 111.

[0111] Also, when the operations described in Operation Example 3 of the imaging device 10 are performed in Steps S11 and S12, the determination by the determination unit 50 in Step S13 as to whether the processing of the processing location 111 is good may include the determination as to whether the processing of the overlap portion 115 is good. For example, the determination unit 50 determines whether the processing of the overlap portion 115 is good based on the luminance value, length, or width of the overlap portion 115 in the image in which the processing location 111 is imaged. The determination unit 50 determines, for example, that it is good if the luminance value, length, or width of the overlap portion 115 is within a predetermined range in the image. Also, when the imaging device 10 is an imaging device for the two-color method, the determination unit 50 may determine whether the processing of the overlap portion 115 is good based on the ratio of the luminance values of the overlap portion 115.

[0112] (Other Embodiments) As described above, the processing status monitoring system and the processing status monitoring method according to the present disclosure have been described based on the embodiments, but the present disclosure is not limited to these embodiments. Without departing from the gist of the present disclosure, various modifications conceived by those skilled in the art applied to the embodiments, and other forms constructed by combining some of the components in the embodiments are also included in the scope of the present disclosure.

[0113] For example, in the above embodiment, the control unit 20 determines the exposure time and ends the exposure of the imaging device 10 after the exposure time has elapsed since the start of the exposure of the imaging device 10, but it is not limited thereto. For example, the control unit 20 may acquire a trigger indicating the timing of the end of the irradiation of the laser beam L from the laser processing machine 200, and based on the trigger, end the exposure of the imaging device 10 after the end time of the irradiation of the laser beam L.

[0114] Also, for example, in Operation Examples 1, 2, and 4 in the above embodiment, the control unit 20 starts the exposure of the imaging device 10 with a delay time of the same time t1 as the overlap time from the start time of the irradiation of the laser beam L to the processing location 111, but it is not limited to this. For example, the control unit 20 may start the exposure of the imaging device 10 before the start time of the irradiation of the laser beam L to the processing location 111, and end the exposure of the imaging device 10 by the same time as the overlap time earlier than the end time of the irradiation of the laser beam L to the processing location 111.

[0115] Moreover, the processing status monitoring system according to the present disclosure does not necessarily include all the components described in the above embodiment, and may be configured only with the components for causing the target operation to be performed.

[0116] Also, in the above embodiment, the processing executed by a specific processing circuit may be executed by another processing circuit. Also, the order of a plurality of processes may be changed, or a plurality of processes may be executed in parallel.

[0117] For example, the processing described in the above embodiment may be realized by centralized processing using a single device, or may be realized by distributed processing using a plurality of devices. Also, the processor that executes the above program may be singular or plural. That is, centralized processing or distributed processing may be performed.

[0118] In addition, in the above embodiment, the processing status monitoring system 100 may be implemented by a plurality of devices or may be implemented as a single device. Further, when the processing status monitoring system 100 is implemented by a plurality of devices, each component included in the processing status monitoring system 100 may be distributed among the plurality of devices in any manner. Also, the plurality of devices may communicate via a network such as the Internet. Moreover, a certain component included in the processing status monitoring system 100 may be a part of another component. For example, in the processing status monitoring system 100, the control unit 20 may be provided in the imaging device 10 or may be provided in the laser processing machine 200.

[0119] Furthermore, the general or specific aspects of the present disclosure may be implemented by a system, a device, a method, an integrated circuit, a computer program, or a recording medium such as a computer-readable CD-ROM. Also, they may be implemented by any combination of a system, a device, a method, an integrated circuit, a computer program, and a recording medium. For example, the present disclosure may be implemented as a processing status monitoring method executed by a computer such as a control device, or may be implemented as a control device that executes the processing status monitoring method. Also, the present disclosure may be implemented as a program for causing a computer to execute the processing status monitoring method, or may be implemented as a computer-readable non-transitory recording medium storing such a program.

Industrial Applicability

[0120] The processing status monitoring system and the processing status monitoring method according to the present disclosure are useful for monitoring the processing status in laser processing.

Explanation of Reference Numerals

[0121] 10 Imaging device 15, 16 Images 20 Control unit 30 Input unit 40 Image acquisition unit 50 Determination unit 60 Storage unit 100 Processing status monitoring system 110 Object to be processed 111 Processing location 112 Transparent member 113 Absorbing member 115 Overlap portion 200 Laser processing machine L Laser beam

Claims

1. A processing status monitoring system for monitoring the processing status when processing a workpiece by irradiating a laser beam while scanning a processing location of the workpiece, an imaging device that images the processing location, and a control unit that controls the driving of the imaging device, when the laser beam irradiated on the processing location is scanned with at least a part of the processing location overlapped, the control unit starts the exposure of the imaging device with a delay time from the start time of the irradiation of the laser beam on the processing location, and ends the exposure of the imaging device after the end time of the irradiation of the laser beam on the processing location, the length of the delay time is the length of the time during which the laser beam is irradiated with the processing location overlapped, A processing status monitoring system.

2. the control unit ends the exposure of the imaging device with a predetermined time delay from the end time, The processing status monitoring system according to claim 1.

3. the predetermined time is 1 second or less, The processing status monitoring system according to claim 2.

4. the imaging device images the processing location by detecting light in the wavelength range of the laser beam, The processing status monitoring system according to claim 1.

5. the imaging device images the processing location by detecting light in a wavelength range different from the wavelength range of the laser beam, The processing status monitoring system according to claim 1.

6. when the laser beam irradiated on the processing location is scanned with the overlap, the control unit, A first control mode in which exposure of the imaging device is started after providing the delay time from the start time of irradiation of the laser beam to the processing location, and the exposure of the imaging device is ended after the end time of irradiation of the laser beam to the processing location; A second control mode in which exposure of the imaging device is started before the start time of irradiation of the laser beam to the processing location, and the exposure of the imaging device is ended after the end time of irradiation of the laser beam to the processing location, and having; The processing status monitoring system according to claim 1.

7. The imaging device further includes a determination unit that determines whether the processing of the processing location is good or bad based on an image obtained by imaging the processing location; The processing status monitoring system according to any one of claims 1 to 6.

8. The determination unit determines whether the processing of the processing location is good or bad based on the luminance value of the image; The processing status monitoring system according to claim 7.

9. The imaging device images the processing location by detecting infrared rays in two different wavelength ranges that are different from the wavelength range of the laser beam; The determination unit determines whether the processing of the processing location is good or bad based on the ratio between the luminance value of the processing location in the image obtained by detecting infrared rays in one of the two wavelength ranges and the luminance value of the processing location in the image obtained by detecting infrared rays in the other of the two wavelength ranges; The processing status monitoring system according to claim 7.

10. A processing status monitoring method for monitoring the processing status when processing a processing object by irradiating a laser beam while scanning a processing location of the processing object, using an imaging device that images the processing location, When the laser beam irradiated to the processing location is scanned so as to overlap at least a part of the processing location, Providing a delay time from the start time of the irradiation of the laser beam to the processing location, and starting the exposure of the imaging device, Ending the exposure of the imaging device after the end time of the irradiation of the laser beam to the processing location, The length of the delay time is the length of the time during which the laser beam is irradiated overlapping the processing location, Processing status monitoring method.

Images