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. The control part starts exposure of the imaging device before a start time of irradiation of the machining place with a laser beam, and finishes exposure of the imaging device after a finish time of irradiation of the machining place with a laser beam.SELECTED DRAWING: Figure 5

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 capable of reducing omission in monitoring the processing status in laser processing.

Means for Solving the Problems

[0006] A processing status monitoring system according to one aspect of the present disclosure is a processing status monitoring system that monitors the processing status when processing a workpiece by irradiating a processing location of the workpiece 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. The control unit starts the exposure of the imaging device before the start time of the irradiation of the laser beam to the processing location, and ends the exposure of the imaging device after the end time of the irradiation of the laser beam to the processing location.

[0007] A processing status monitoring method according to one aspect of the present disclosure is a processing status monitoring method that monitors the processing status when processing a workpiece by irradiating a processing location of the workpiece while scanning a laser beam, using an imaging device that images the processing location. The method starts the exposure of the imaging device before the start time of the irradiation of the laser beam to the processing location, and ends the exposure of the imaging device after the end time of the irradiation of the laser beam to the processing location.

Advantages of the Invention

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

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 11A

Figure 11B

Figure 11C

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Mode for Carrying Out the Invention

[0010] (Process of Arriving at One Aspect of the Present Disclosure) Prior to specifically describing the embodiments of the present disclosure, the process of arriving at one 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, the processing location of the object to be processed is imaged by an imaging device using the light generated by the laser processing. At this time, when a high-speed camera is used as the imaging device as in Patent Document 1, there is a problem that the processing status of the location where the laser beam is scanned during the non-exposure period occurring 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 a high-speed camera is used, 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 performed alternately, the readout period becomes a non-exposure period, and the processing status of the location where the laser beam 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, the locations where the light generated by the laser processing is not detected by the high-speed camera among the processed locations scanned by the laser beam are surrounded by broken lines. As shown in FIGS. 1A and 1B, when imaging in the ITR mode, the light generated at the locations where the laser beam is scanned during the readout period within the frame period cannot be detected, and there is a period during which the processing status cannot be monitored. Also, multiple images are captured for one processed location.

[0013] Also, in the IWR (Integrate While Read) mode, which is a readout mode in a high-speed camera 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 location 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 scanned by the laser beam 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 state monitoring system and a processing state monitoring method capable of reducing leakage in monitoring the processing state in laser processing.

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

[0016] For example, a processing state monitoring system according to a first aspect of the present disclosure is a processing state monitoring system that monitors the processing state when processing a processing object by irradiating a processing location of the processing object while scanning a laser beam, and includes an imaging device that images the processing location and a control unit that controls driving of the imaging device. The control unit starts exposure of the imaging device before a start time of irradiation of the laser beam to the processing location and ends exposure of the imaging device after an end time of irradiation of the laser beam to the processing location.

[0017] As a result, since the imaging device continues to be exposed from the start to the end of irradiation of the laser beam to the processing location, it is possible to monitor the processing state without omission from the start point to the end point of the scanning of the laser beam at the processing location. Therefore, in the processing state monitoring system according to this aspect, leakage in monitoring the processing state in laser processing can be reduced.

[0018] Further, for example, a processing state monitoring system according to a second aspect of the present disclosure is a processing state monitoring system according to the first aspect, and the control unit ends exposure of the imaging device with a predetermined time delay from the end time.

[0019] As a result, since light emitted from the processing location during the cooling process of the processing location after the irradiation of the laser beam is also detected by the imaging device, more accurate monitoring of the processing state becomes possible.

[0020] Further, for example, a processing state monitoring system according to a third aspect of the present disclosure is a processing state monitoring system according to the second aspect, and the predetermined time is 1 second or less.

[0021] As a result, since it is possible to suppress an increase in the exposure time of the imaging device after the irradiation of the laser light ends, it is possible to suppress an increase in noise due to the generation of dark current.

[0022] Further, for example, the processing state monitoring system according to the fourth aspect of the present disclosure is the processing state monitoring system according to any one of the first aspect to the third aspect, and the control unit starts the exposure of the imaging device at the start time.

[0023] As a result, the imaging device starts exposure simultaneously with the start of irradiation of the laser light to the processing portion. Therefore, since it is possible to suppress an increase in the exposure time of the imaging device by preventing the imaging device from being exposed before the start of irradiation of the laser light, it is possible to suppress an increase in noise due to the generation of dark current.

[0024] Further, for example, the processing state monitoring system according to the fifth aspect of the present disclosure is the processing state monitoring system according to any one of the first aspect to the fourth aspect, and when the laser light is irradiated a plurality of times to the same processing portion, the control unit starts the exposure of the imaging device before the start time of irradiation of the laser light to the processing portion in each of the plurality of times, and ends the exposure of the imaging device after the end time of irradiation of the laser light to the processing portion.

[0025] As a result, in each of the plurality of irradiations of the laser light to the same processing portion, the processing state can be monitored individually.

[0026] Further, for example, the processing state monitoring system according to the sixth aspect of the present disclosure is the processing state monitoring system according to the fifth aspect, and the control unit causes the imaging device to image the processing portion under conditions where the gains are different from each other in each of the plurality of times.

[0027] As a result, even when the amount of light from the processing location changes due to differences in the temperature of the processing location or the like each time the laser light is irradiated to the same processing location, the gain can be changed to perform imaging with an appropriate gain, so that the S / N (signal / noise) when imaging the processing location can be increased.

[0028] 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 aspect to the fourth aspect. When the laser light is irradiated to the same processing location a plurality of times, the control unit does not expose the imaging device during the time when the laser light is irradiated to the processing location in the times other than the last time among the plurality of times, and at the last time, exposes the imaging device before the start time of the irradiation of the laser light to the processing location, and ends the exposure of the imaging device after the end time of the irradiation of the laser light to the processing location.

[0029] As a result, an image in which the light from the processing location in only the last irradiation of the laser light to the same processing location is detected can be obtained. Since the light from the processing location in the last irradiation of the laser light can also reflect the processing status of the processing location before the last irradiation of the laser light, the processing status in the irradiation of the laser light in the times other than the last time can also be indirectly monitored. Therefore, while reducing the omission of monitoring the processing status in laser processing, the amount of data in monitoring the processing status can be reduced. In addition, since the exposure time of the imaging device can be shortened compared to the case where the exposure is started from the start of the first irradiation of the laser light, an increase in noise due to the generation of dark current can be suppressed.

[0030] 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 any one of the first aspect to the seventh aspect, and the imaging device images the processing location by detecting light in the wavelength range of the laser light.

[0031] As a result, the processing status can be monitored using the reflected light of the laser light by the processing location.

[0032] Further, for example, the processing status monitoring system according to the ninth aspect of the present disclosure is the processing status monitoring system according to any one of the first to eighth aspects, and the imaging device images the processing location by detecting light in a wavelength range different from the wavelength range of the laser light.

[0033] Thereby, the processing status can be monitored by using the thermal radiation or plasma emission generated by irradiating the processing location with the laser light.

[0034] Further, for example, the processing status monitoring system according to the tenth aspect of the present disclosure is the processing status monitoring system according to any one of the first to ninth 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 imaging the processing location.

[0035] Thereby, the presence or absence of an abnormality in laser processing can be monitored.

[0036] Further, for example, the processing status monitoring system according to the eleventh aspect of the present disclosure is the processing status monitoring system according to the tenth 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.

[0037] Thereby, it is possible to determine whether the processing is good or bad based on whether the light generated in the laser processing is abnormal.

[0038] Further, for example, the processing status monitoring system according to the twelfth aspect of the present disclosure is the processing status monitoring system according to the tenth aspect. 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 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 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.

[0039] Accordingly, by utilizing the principle of the two-color method, it is possible to determine the quality of processing based on whether the temperature at the processing location is abnormal or not.

[0040] Further, for example, the processing status monitoring method according to the 13th aspect of the present disclosure is a processing status monitoring method for monitoring the processing status when processing the processing object by irradiating a laser beam while scanning the processing location of the processing object, using an imaging device that images the processing location, wherein the exposure of the imaging device is started before the start time of the irradiation of the laser beam to the processing location, and the exposure of the imaging device is ended after the end time of the irradiation of the laser beam to the processing location.

[0041] Accordingly, similar to the processing status monitoring system according to the first aspect described above, it is possible to reduce the omission of monitoring the processing status in laser processing.

[0042] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the embodiments described below are all examples showing 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 merely 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. In addition, 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.

[0043] Moreover, the various elements shown in the drawings are merely schematically shown for the purpose of understanding the present disclosure, and the dimensional ratios, appearances, etc. may be different from the actual ones. That is, each figure is a schematic diagram and is not necessarily drawn precisely. Therefore, for example, the scales etc. in each figure do not necessarily match.

[0044] In addition, in this specification, terms indicating the relationship between elements such as parallel or coincident, terms indicating the shape of elements such as circular or rectangular, and numerical ranges are not expressions representing only a strict meaning, but are expressions meaning substantially equivalent ranges, for example, including differences of about several percent.

[0045] In addition, in this specification, not only visible light but also invisible light such as ultraviolet rays and infrared rays are, for convenience, expressed as "light".

[0046] (Embodiment) [Configuration] First, the configuration of the processing status monitoring system according to the embodiment will be described.

[0047] 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 broken line.

[0048] 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 portion 111 of the workpiece 110 with the laser beam L while scanning. 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 scanned over the processing portion 111 of the workpiece 110. The processing portion 111 is a 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. The workpiece 110 is, for example, a metal member or a resin member or the like, but is not particularly limited. Also, in FIG. 3, only the surface of the workpiece 110 is shown. The shape of the workpiece 110 is not particularly limited. Also, the workpiece 110 may be a single member, or may be composed of two or more members that are welded to each other by laser processing.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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, for example, by 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.

[0053] 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.

[0054] 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 calculating the temperature from the ratio of the detection results in two different wavelength ranges, that is, the luminance ratio, by detecting infrared rays due to thermal radiation from the same position in two different wavelength ranges. The imaging device for 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 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 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 two-color method include, for example, imaging devices disclosed in Patent Documents 2 to 4. Note that the imaging device for two-color method is not limited to these examples and is not particularly limited. For example, an imaging element in which two or more photoelectric conversion elements having different wavelength ranges with sensitivity are stacked may be used for the imaging device for two-color method.

[0055] 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 a control signal to the imaging device 10, for example. The control unit 20 controls the exposure timing and time of the imaging device 10 based on, for example, the irradiation time of the laser beam L and the timing of the start of irradiation of the laser beam L. The control unit 20 acquires, for example, a trigger regarding the irradiation start timing of the laser beam L and information regarding the irradiation time of the laser beam L from the laser processing machine 200. The control unit 20 may acquire information regarding the irradiation time of the laser beam L 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.

[0056] The input unit 30 is an interface that receives inputs 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.

[0057] The input unit 30 receives, for example, inputs of information regarding the laser processing conditions by the laser processing machine 200, such as information regarding the irradiation time of the laser beam L by the laser processing machine 200 from the user. As the information regarding the irradiation time of the laser beam L, for example, not only the information directly indicating the irradiation time of the laser beam L but also the information for calculating the laser beam L, such as the scanning speed of the laser beam L and the scanning distance 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.

[0058] 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 the 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.

[0059] The determination unit 50 determines the quality of the processing of the processing location 111 based on the image captured of 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 acquired by an external display, for example, and the determination result is displayed on the display. Also, the determination unit 50 may output a determination result indicating that the processing is defective to an external alarm, and the alarm that has acquired the determination result may output an alarm. Further, the determination unit 50 may store the determination result in the storage unit 60. Also, 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.

[0060] 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 etc. that includes 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 each be realized by an individual microcomputer or processor 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. Also, 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.

[0061] 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.

[0062] [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.

[0063] (1) Operation example 1 First, an 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 is irradiated once on the processing location 111 of one workpiece 110 as shown in FIG. 3 will be described.

[0064] FIG. 5 is a timing chart of operation example 1 of the imaging device 10 according to the present embodiment. In "Laser beam irradiation" in FIG. 5, the irradiation timing of the laser beam L is shown. In "Laser beam irradiation" in FIG. 5, the laser beam L is emitted by the laser processing machine 200 during the period when the chart is at a high level. In "Exposure" in FIG. 5, the timing at which the imaging device 10 performs exposure is shown. In "Exposure" in FIG. 5, the exposure of the imaging device 10 is performed during the period when the chart is at a high level. In "Reading" in FIG. 5, the timing at which the imaging device 10 reads the signal obtained by exposure is shown. In "Reading" in FIG. 5, 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. 5 in the figures of other timing charts.

[0065] As shown in FIG. 5, the control unit 20 starts the exposure of the imaging device 10 at the start time of the irradiation of the laser beam L on the processing location 111. For example, the control unit 20 acquires a trigger indicating the irradiation start timing of the laser beam L 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.

[0066] The laser processing machine 200, for example, starts scanning simultaneously with the start of the irradiation of the laser beam L, and irradiates the processing location 111 while scanning the laser beam L for an 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.

[0067] 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.

[0068] The control unit 20 determines, for example, the exposure time by adding a predetermined time Δt to 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, for example, 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 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. The imaging device 10 generates an image of the processing location 111 based on the read-out signal, and outputs the generated image to the image acquisition unit 40.

[0070] FIG. 6 is a schematic diagram showing an example of the image 15 generated by the imaging device 10 in Operation Example 1. In FIG. 6, the image 15 in the case where the laser processing is normally performed is shown. 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. Even when the imaging device 10 images the processing location 111 by detecting light other than thermal radiation from the processing location 111, an image 15 as shown in FIG. 6 is captured. In the image 15 of FIG. 6, the 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. 6, 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 is reversed from the actual image.

[0071] Also, in the processing location 111 shown in the image 15 in FIG. 6, point A is the starting point of the scanning of the laser beam L, point B is a point in the middle of the scanning of the laser beam L, and point C is the ending point of the scanning of the laser beam L.

[0072] As shown in FIG. 6, in the image 15, light from the processed portion 111 scanned by the laser beam L is detected without interruption from point A, which is the start point of the scanning of the laser beam L, to point C, which is the end point of the scanning. This is because the imaging device 10 starts exposure before the irradiation of the laser beam L and continues the exposure until the irradiation time TL of the laser beam L ends. Thus, in the operation example 1, there is no period during which the processing status during laser processing of the processed portion 111 cannot be monitored, and it is possible to reduce the omission of monitoring the processing status in laser processing. Further, since the processing status of the entire range of the processed portion 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.

[0073] Further, in the operation example 1, the processing status in the vicinity of point C, which is 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. 7.

[0074] FIG. 7 is a diagram schematically showing the time change of the thermal radiation intensity from point A to point C in FIG. 6. As shown in FIG. 7, at any location in the processing portion 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. 7, at points A and B, after the laser beam L reaches, the irradiation of the laser beam L on the processing portion 111 continues because the laser beam L is scanned to other locations. On the other hand, at point C, since it is the end point of the scan, the irradiation of the laser beam L on the processing portion 111 ends immediately after the laser beam L reaches. 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 portion 111 ends, at point C, the thermal radiation during the process of the thermal radiation intensity decreasing over a predetermined time is not detected by the imaging device 10. That is, the amount of the signal when the imaging device 10 detects the light from point C becomes less than that of other parts of the processing portion 111. In contrast, in operation example 1 shown in FIG. 6, 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 of the thermal radiation intensity decreasing over a predetermined time at point C can also be detected. Therefore, at point C as well, the thermal radiation is detected by the imaging device 10 under the same conditions as other parts such as points A and B, and more accurate monitoring of the processing situation becomes possible.

[0075] The predetermined time Δt is, for example, 1 second or less. This can ensure the time for exposing the decreasing thermal radiation at the end point of the scanning of the laser beam L, suppress the increase in the exposure time of the imaging device 10 after the irradiation of the laser beam L ends, and 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 larger 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 an instantaneous light emission phenomenon 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 when the charge amount of each pixel does not saturate 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 decrease rate of thermal radiation varies depending on the processing conditions and the material of the processing location 111, but for example, it is 10 milliseconds or more, and may be 30 milliseconds or more. The predetermined time Δt is, for example, set based on the measurement result of the time for the thermal radiation to decrease after the irradiation of the laser beam L is measured in advance. 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. Further, 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.

[0076] In the example shown in FIG. 5, the laser beam L emitted from the laser processing machine 200 was continuous light in which the light emission continued from the start to the end of the irradiation of the laser beam L, 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.

[0077] 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 the 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 with a delay of a predetermined time Δt from 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, it is possible to determine the irradiation time TL of the laser beam L by dividing the scanning distance of the laser beam L by the scanning time of the laser beam L.

[0078] (2) Operation Example 2 Next, the operation example 2 of the imaging device 10 will be described. In the following description of the operation example 2, the description will focus on the differences from the operation example 1, and the description of the common points will be omitted or simplified. FIG. 9 is another schematic diagram for explaining the processing status monitoring system 100 according to the present embodiment. In the operation example 2, an example of the operation of the imaging device 10 when the laser beam L is irradiated once to each of the processing portions 111A and 111B of the plurality of workpieces 110A and 110B as shown in FIG. 9 will be described.

[0079] In the example shown in FIG. 9, the processing portions 111A and 111B are each rectangular annular. When irradiating the processing portions 111A and 111B with the laser beam L, the laser beam L is scanned so as to make one round in a rectangular annular shape in one irradiation time. In the example shown in FIG. 9, the objects to be processed 110A and 110B each include 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 objects to be processed 110A and 110B, 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 onto the processing portions 111A and 111B, the transmissive member 112 and the absorptive member 113 are welded at the processing portions 111A and 111B. Note that the objects to be processed 110A and 110B are not limited to an example in which they are composed of members welded to each other, and may be a single member. Also, the processing portions 111A and 111B may be different portions of one object to be processed.

[0080] FIG. 10 is a timing chart of Operation Example 2 of the imaging device 10 according to the present embodiment.

[0081] As shown in FIG. 10, 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 111A. The control unit 20, for example, acquires a trigger indicating the timing of the start of the irradiation of the laser beam L to the processing portion 111A 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. 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 111A, and irradiates the processing portion 111A while scanning the laser beam L for an irradiation time TLA from the start of the irradiation of the laser beam L.

[0082] 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 to the processing location 111A. Here, the exposure of the imaging device 10 corresponding to the irradiation time TLA is defined as the exposure of Frame 1.

[0083] Next, after the exposure of Frame 1 ends, the imaging device 10 reads out the signal obtained by the exposure. Based on the signal read out in Frame 1, the imaging device 10 generates an image of the processing location 111A and outputs the generated image to the image acquisition unit 40.

[0084] Next, 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 location 111B after a predetermined time has elapsed from the end time of the irradiation of the laser beam L to the processing location 111A. 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 location 111B 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. The laser processing machine 200, for example, starts scanning simultaneously with the start of the irradiation of the laser beam L to the processing location 111B, and irradiates the processing location 111B while scanning the laser beam L for the irradiation time TLB from the start of the irradiation of the laser beam L. In the example shown in FIG. 10, the irradiation of the laser beam L to the processing location 111B and the re-exposure of the imaging device 10 start during the readout period of Frame 1, but may also start after the readout period of Frame 1. Further, the control unit 20 does not necessarily have to acquire a trigger indicating the timing of the start of the irradiation of the laser beam L to the processing location 111B from the laser processing machine 200. For example, the control unit 20 acquires information regarding the irradiation time TLA and the interval between the end of the irradiation of the laser beam L to the processing location 111A and the start of the irradiation of the laser beam L to the processing location 111B, and based on the information, may start the exposure of the imaging device 10 in synchronization with the start of the irradiation of the laser beam L to the processing location 111B.

[0085] 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 to the processing location 111B. Here, the exposure of the imaging device 10 corresponding to the irradiation time TLB is set as the exposure of frame 2.

[0086] Next, after the exposure of frame 2 ends, the imaging device 10 reads out the signal obtained by the exposure. Based on the signal read out in frame 2, the imaging device 10 generates an image of the processing location 111B and outputs the generated image to the image acquisition unit 40.

[0087] As described above, in operation example 2, in each irradiation of the laser beam L to the plurality of processing locations 111A and 111B, 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 location, and 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 to the processing location.

[0088] FIG. 11A is a schematic diagram showing an example of an image 16A generated by the imaging device 10 in operation example 2. FIG. 11B is a schematic diagram showing an example of another image 16B generated by the imaging device 10 in operation example 2. FIG. 11C is a schematic diagram showing another example of the image 16A generated by the imaging device 10 in operation example 2. In FIG. 11A, an image 16A of the processing location 111A when the laser processing is normally performed is shown. Further, in FIG. 11B, an image 16B of the processing location 111B when the laser processing is normally performed is shown. Further, in FIG. 11C, an image 16A of the processing location 111A when abnormal heat generation occurs in the laser processing is shown. The image 16A is an image obtained by the imaging device 10 detecting the thermal radiation from the processing location 111A in the above-mentioned frame 1. The image 16B is an image obtained by the imaging device 10 detecting the thermal radiation from the processing location 111B in the above-mentioned frame 2.

[0089] As shown in Fig. 11A, in the image 16A of the processed portion 111A when the laser processing is normally performed, the light from the processed portion 111A scanned by the laser beam L is detected in a rectangular ring shape without interruption. Also, as shown in Fig. 11B, in the image 16B of the processed portion 111B when the laser processing is normally performed, the light from the processed portion 111B scanned by the laser beam L is detected in a rectangular ring shape without interruption at a position different from that of the processed portion 111A.

[0090] On the other hand, as shown in Fig. 11C, in the image 16A of the processed portion 111A when abnormal heat generation occurs in the laser processing, there are abnormal light emission portions AL with high luminance values and flare generation portions FL due to the abnormal heat generation. If the imaging device 10 images the entire processing periods of the processed portions 111A and 111B in a single exposure, the processed portions 111A and 111B will appear in one image. Therefore, when there are abnormal light emission portions AL and flare generation portions FL as shown in Fig. 11C, even if the processed portion 111B is normally laser processed, the abnormal light emission portions AL and flare generation portions FL will overlap at the position where the processed portion 111B appears. As a result, it may become difficult to determine the quality of the laser processing for the processed portion 111B. In contrast, as in the operation example 2, by imaging the processed portions 111A and 111B in separate images, it is possible to suppress the influence of the processing status of an individual processed portion on the monitoring of the processing status of other processed portions in the monitoring of the processing status in the laser processing.

[0091] (3) Operation Example 3 Next, the operation example 3 of the imaging device 10 will be described. In the following description of the operation example 3, the description will focus on the differences from the operation examples 1 and 2, and the description of the common points will be omitted or simplified. In the operation example 3, an example different from the operation example 2 of the operation of the imaging device 10 when the laser beam L is irradiated once to each of the processed portions 111A and 111B of a plurality of workpieces 110A and 110B as shown in Fig. 9 will be described.

[0092] FIG. 12 is a timing chart of Operation Example 3 of the imaging device 10 according to the present embodiment.

[0093] As shown in FIG. 12, 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 location 111A. 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 location 111A 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. The laser processing machine 200, for example, starts scanning simultaneously with the start of the irradiation of the laser beam L to the processing location 111A, and irradiates the processing location 111A while scanning the laser beam L for an irradiation time TLA from the start of the irradiation of the laser beam L. Further, the laser processing machine 200 starts the irradiation of the laser beam L to the processing location 111B after a predetermined time has elapsed from the end of the irradiation of the laser beam L to the processing location 111A, and irradiates the processing location 111B while scanning the laser beam L for an irradiation time TLB from the start of the irradiation of the laser beam L. The control unit 20 continues the exposure of the imaging device 10 that started at the start time of the irradiation of the laser beam L to the processing location 111A also during the period from the end of the irradiation of the laser beam L to the processing location 111A to the start of the irradiation of the laser beam L to the processing location 111B. That is, the control unit 20 continues the exposure of the imaging device 10 that started at the start time of the irradiation of the laser beam L to the processing location 111A while the laser beam L is being irradiated to the plurality of processing locations 111A and 111B.

[0094] 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 to the processing location 111B.

[0095] The control unit 20 determines, for example, the exposure time by adding up the irradiation times TLA and TLB, the interval between the end of the irradiation time TLA and the start of the irradiation time TLB, and a predetermined time Δt, and ends the exposure of the imaging device 10 after the elapse of the exposure time from the start of the exposure of the imaging device 10. The control unit 20 acquires, for example, information regarding the irradiation times TLA and TLB and the interval between the end of the irradiation time TLA and the start of the irradiation time TLB from the input unit 30 or the laser processing machine 200 as information regarding the time from the start of the irradiation time TLA to the end of the irradiation time TLB.

[0096] 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 locations 111A and 111B and outputs the generated image to the image acquisition unit 40.

[0097] FIG. 13 is a schematic diagram showing an example of the image 17 generated by the imaging device 10 in operation example 3. In FIG. 13, the image 17 in the case where the laser processing is normally performed is shown. The image 17 is an image obtained by the imaging device 10 detecting the thermal radiation from the processing locations 111A and 111B to image the processing locations 111A and 111B.

[0098] In the image 17 in the case where the laser processing is normally performed, the light from each of the processing locations 111A and 111B scanned by the laser beam L is detected in a rectangular ring shape without interruption. This is because the imaging device 10 starts the exposure before the start of the irradiation of the laser beam L and continues the exposure until the irradiation times TLA and TLB of the laser beam L to all the processing locations 111A and 111B existing in the imaging range of the imaging device 10 end. Thereby, since the processing status of the processing locations 111A and 111B can be monitored with one image 17, the data amount when saving the monitoring result can be reduced.

[0099] (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 is irradiated a plurality of times on the same processing location will be described.

[0100] FIG. 14 is a diagram for explaining an example of the temperature of the processing location 111C when the laser beam L is irradiated a plurality of times on the same processing location 111C. In FIG. 14, a top view is shown when the laser beam L is irradiated on the rectangular annular processing location 111C in the object to be processed 110C. The laser beam L is scanned so as to make one round in a rectangular ring by one irradiation of the laser beam L on the processing location 111C. The object to be processed 110C includes, for example, a transmissive member 112 and an absorptive member 113 in the same manner as the object to be processed 110A, and the transmissive member 112 and the absorptive member 113 are welded to each other by the laser beam L. Further, as shown in FIG. 14, in operation example 4, the laser beam L is irradiated three times on the same processing location 111C. Note that the number of times the laser beam L is irradiated on the same processing location 111C is not particularly limited, and may be two times, or four times or more.

[0101] Particularly, when the object to be processed 110C is large, if it is processed by one irradiation of the laser beam L, 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 object to be processed 110C. In such a case, by increasing the scanning speed of the laser beam L and irradiating the same processing location 111C with the laser beam a plurality of times, although the amount of heat input per time decreases, the entire processing location 111C can be gradually heated almost simultaneously, which may be effective for obtaining a good processing result.

[0102] As shown in FIG. 14, when the laser beam L is irradiated a plurality of times on the same processing location 111C, the temperature of the processing location 111C increases as the number of irradiations of the laser beam L increases. Thereby, the welding strength between the transmissive member 112 and the absorptive member 113 in the object to be processed 110C can be increased.

[0103] FIG. 15 is a timing chart of operation example 4 of the imaging device 10 according to the present embodiment.

[0104] As shown in FIG. 15, the control unit 20 starts the exposure of the imaging device 10 at the start time of the first irradiation of the laser beam L to the processing location 111C. For example, the control unit 20 acquires a trigger indicating the timing of the start of the first irradiation of the laser beam L to the processing location 111C 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 first irradiation of the laser beam L. The laser processing machine 200, for example, starts scanning simultaneously with the start of the first irradiation of the laser beam L to the processing location 111C, and irradiates the processing location 111C while scanning the laser beam L for the irradiation time TL from the start of the first irradiation of the laser beam L.

[0105] Furthermore, the laser processing machine 200 repeatedly irradiates the same processing location 111C while scanning the laser beam L. In the example shown in FIG. 15, the laser processing machine 200 starts the second irradiation of the laser beam L to the processing location 111C after a predetermined time has elapsed from the end of the first irradiation of the laser beam L to the processing location 111C, and irradiates the processing location 111C while scanning the laser beam L for the irradiation time TL from the start of the second irradiation of the laser beam L. Also, the laser processing machine 200 starts the third irradiation of the laser beam L to the processing location 111C after a predetermined time has elapsed from the end of the second irradiation of the laser beam L to the processing location 111C, and irradiates the processing location 111C while scanning the laser beam L for the irradiation time TL from the start of the third irradiation of the laser beam L. The control unit 20 continues the exposure started at the start time of the first irradiation of the laser beam L to the processing location 111C in the imaging device 10 while the laser beam L is irradiated to the same processing location 111C a plurality of times. In the example shown in FIG. 15, the irradiation time TL in the first to third irradiations of the laser beam L is the same, but it may be different. That is, the scanning speed of the laser beam L may change in the first to third irradiations of the laser beam L.

[0106] 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 third irradiation of the laser beam L to the processing location 111C.

[0107] The control unit 20 determines, for example, the exposure time as the sum of the irradiation time TL for the number of times the laser beam L is irradiated to the same processing location 111C, the interval when the laser beam L is repeatedly irradiated to the same processing location 111C, and the 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. The control unit 20 acquires, for example, information regarding the irradiation time TL, the number of times the laser beam L is irradiated to the same processing location 111C, and the interval when the laser beam L is repeatedly irradiated to the same processing location 111C, from the input unit 30 or the laser processing machine 20 as information regarding the time from the start of the irradiation of the first laser beam L to the end of the irradiation of the last laser beam.

[0108] Next, after the exposure ends, the imaging device 10 reads out the signal obtained by the exposure. The imaging device 10 generates an image of the processing location 111C based on the read signal, and outputs the generated image to the image acquisition unit 40. As a result, an image is obtained in which the light from the processing location 111C irradiated with the laser beam L a plurality of times is integrated and detected.

[0109] (5) Operation Example 5 Next, operation example 5 of the imaging device 10 will be described. In the following description of operation example 5, the differences from operation examples 1 to 4 will be mainly described, and the description of the common points will be omitted or simplified. In operation example 5, an example different from operation example 4 of the operation when the laser beam L is irradiated a plurality of times to the same processing location 111C as shown in FIG. 14 will be described.

[0110] FIG. 16 is a timing chart of operation example 5 of the imaging device 10 according to the present embodiment.

[0111] As shown in FIG. 16, the control unit 20 starts the exposure of the imaging device 10 at the start time of the first irradiation of the laser beam L to the processing location 111C. For example, the control unit 20 acquires a trigger indicating the timing of the start of the first irradiation of the laser beam L to the processing location 111C 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 first irradiation of the laser beam L. The laser processing machine 200, for example, starts scanning simultaneously with the start of the first irradiation of the laser beam L to the processing location 111C, and irradiates the processing location 111C while scanning the laser beam L for the irradiation time TL from the start of the first irradiation of the laser beam L.

[0112] 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 first irradiation of the laser beam L to the processing location 111C. Here, the exposure of the imaging device 10 corresponding to the first irradiation time TL is defined as the exposure of frame 1.

[0113] Next, after the exposure of frame 1 ends, the imaging device 10 reads out the signal obtained by the exposure. Based on the signal read out in frame 1, the imaging device 10 generates an image of the processing location 111C and outputs the generated image to the image acquisition unit 40.

[0114] In each of the multiple irradiations of the laser beam L to the same processing location 111C, 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 location 111C, and 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 to the processing location 111C.

[0115] In the example shown in FIG. 16, the control unit 20 starts the exposure of the imaging device 10 at the start time of the second irradiation of the laser beam L to the processing location 111C after a predetermined time has elapsed since the end time of the first irradiation of the laser beam L to the processing location 111C. The control unit 20 acquires, for example, information regarding the irradiation time TL and the interval between the end time of the first irradiation of the laser beam L and the start time of the second irradiation of the laser beam L, and based on the information, starts the exposure of the imaging device 10 in synchronization with the start of the second irradiation of the laser beam L to the processing location 111C. Note that the control unit 20 may acquire a trigger indicating the timing of the start of the second irradiation of the laser beam L to the processing location 111C from the laser processing machine 200, and based on the trigger, start the exposure of the imaging device 10 in synchronization with the start of the second irradiation of the laser beam L.

[0116] 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 second irradiation of the laser beam L to the processing location 111C. Here, the exposure of the imaging device 10 corresponding to the second irradiation time TL is set as the exposure of frame 2.

[0117] Next, after the exposure of frame 2 ends, the imaging device 10 reads out the signal obtained by the exposure. Based on the signal read out in frame 2, the imaging device 10 generates an image of the processing location 111C and outputs the generated image to the image acquisition unit 40.

[0118] Also in the third irradiation of the laser beam L to the processing location 111C, the same operation as the second irradiation of the laser beam L is performed. The exposure of the imaging device 10 corresponding to the third irradiation time TL is set as the exposure of frame 3. Based on the signal read out in frame 3, the imaging device 10 generates an image of the processing location 111C and outputs the generated image to the image acquisition unit 40. Thus, in operation example 5, an image of the processing location 111C is obtained corresponding to each of a plurality of irradiations of the laser beam L to the same processing location 111C. Therefore, in each of a plurality of irradiations of the laser beam L to the same processing location 111C, the processing status can be monitored individually.

[0119] Also, in Operation Example 5, in each of the multiple irradiations of the laser beam L on the same processing location 111C, the control unit 20 may cause the imaging device 10 to image the processing location 111C under conditions where gains are different such that exposure amounts are different from each other. Thereby, imaging can be performed with a gain corresponding to the change in the processing state of the processing location 111C. For example, the control unit 20 causes the imaging device 10 to image the processing location 111C such that the gain decreases as the number of irradiations of the laser beam L on the same processing location 111C increases. As described with reference to FIG. 14, as the number of irradiations of the laser beam L increases, the temperature of the processing location 111C rises, and thus the amount of thermal radiation also increases. Therefore, by decreasing the gain as the number of irradiations of the laser beam L on the same processing location 111C increases, imaging is performed with a high gain when the amount of thermal radiation is small, and imaging is performed with a low gain when the amount of thermal radiation is large. As a result, the S / N when imaging the processing location 111C can be increased. The gain when imaging the processing location 111C is, for example, the gain for an analog signal, and is adjusted by changing the sensitivity of the imaging element of the imaging device 10 or the like. Note that the control unit 20 may cause the imaging device 10 to image the processing location 111C such that the gain increases as the number of irradiations of the laser beam L on the same processing location 111C increases when the imaging device 10 images the reflected light of the laser beam L and the reflectance at the processing location 111C decreases due to the irradiation of the laser beam L. Further, an electronically controllable variable aperture may be provided in the imaging device 10, and the control unit 20 may cause the imaging device 10 to image the processing location 111C under conditions where aperture values are different from each other in each of the multiple irradiations of the laser beam L on the same processing location 111C. Further, a movable exposure adjustment mechanism equipped with a plurality of density filters having different electronically controllable optical densities, a variable density filter composed of two polarizing filters where one rotates, or an electronic density filter using liquid crystal may be provided in the imaging device 10, and the control unit 20 may cause the imaging device 10 to image the processing location 111C under conditions where the optical densities of the filters are different from each other in each of the multiple irradiations of the laser beam L on the same processing location 111C.

[0120] (6) Operation Example 6 Next, an operation example 6 of the imaging device 10 will be described. In the following description of operation example 6, the description will focus on the differences from operation examples 1 to 5, and the description of common points will be omitted or simplified. In operation example 6, an example different from operation examples 4 and 5 of the operation when the laser beam L is irradiated a plurality of times to the same processing location 111C as shown in FIG. 14 will be described.

[0121] FIG. 17 is a timing chart of operation example 6 of the imaging device 10 according to the present embodiment.

[0122] As shown in FIG. 17, in the first and second irradiations of the laser beam L for the plurality of irradiations of the laser beam L to the same processing location 111C except for the last time, the control unit 20 does not expose the imaging device 10 during the irradiation time TL in which the laser beam L is irradiated to the processing location 111C. Then, the control unit 20 starts the exposure of the imaging device 10 at the start time of the irradiation of the third laser beam L which is the last time of the irradiation of the laser beam L to the processing location 111C. For example, the control unit 20 acquires a trigger indicating the timing of the start of the third irradiation of the laser beam L to the processing location 111C 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 third irradiation of the laser beam L. Note that the control unit 20 may acquire a trigger indicating the timing of the start of the first irradiation of the laser beam L to the processing location 111C from the laser processing machine 200, and delay the start of the exposure of the imaging device 10 from the timing of the start of the first irradiation of the laser beam L by the irradiation time TL of the first and second laser beams L and the interval when the laser beam L is repeatedly irradiated to the same processing location 111C.

[0123] 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 third irradiation of the laser beam L to the processing location 111C.

[0124] 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 111C and outputs the generated image to the image acquisition unit 40. As a result, an image in which the light from the processing location 111C in only the last pass of the laser beam L irradiation on the processing location 111C is detected is obtained. When the laser beam L is irradiated a plurality of times on the same processing location 111C, it is important whether the temperature of the processing location 111C reaches the target temperature at the time of the last irradiation of the laser beam L.

[0125] Also, if an abnormal temperature occurs during the irradiation of the laser beam L in passes other than the last pass, it may also be reflected in the image of the processing location 111C at the time of the last irradiation of the laser beam L. Therefore, by obtaining an image in which the light from the processing location 111C in only the last pass of the laser beam L irradiation on the processing location 111C is detected, the processing status in the irradiation of the laser beam L in passes other than the last pass can also be indirectly monitored. Thus, while reducing the omission of monitoring the processing status in laser processing, the amount of data in monitoring the processing status can be reduced. In addition, since the exposure time of the imaging device 10 can be shortened compared to the case where the exposure is started from the start of the first irradiation of the laser beam L, an increase in noise due to the generation of dark current can be suppressed.

[0126] [Operation of the Processing Status Monitoring System] Next, an example of the operation of the processing status monitoring system 100 will be described. FIG. 18 is a flowchart showing an example of the operation of the processing status monitoring system 100 according to the present embodiment. Hereinafter, the description will focus on an example of the operation of the processing status monitoring system 100 when the imaging device 10 performs the operation of the above operation example 1.

[0127] As shown in FIG. 18, first, 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 (step S11). 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 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). In the above operation example 1, 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. Thereby, the imaging device 10 continues the exposure longer than the irradiation time TL of the laser beam L, and detects the light from the processing location 111 from the start to the end of the irradiation of the laser beam L in one exposure. 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.

[0128] Details of the operations of the processing status monitoring system 100 in steps S11 and S12 are as described in the above operation example 1 of the imaging device 10.

[0129] Next, the determination unit 50 determines whether the processing of the processing location 111 is good or bad based on the image captured by the imaging device 10 of the processing location 111 (step S13). The determination unit 50 outputs the determination result. The determination unit 50 acquires, for example, an image of the processing location 111 from the image acquisition unit 40, but may also acquire it directly from the imaging device 10. The determination unit 50 performs, for example, contour extraction of the location where the processing location 111 appears from the image of the processing location 111, and uses the location within the extracted contour for the determination.

[0130] The determination unit 50 determines the quality of the processing of the processing location 111 based on, for example, the luminance value of the image in which the processing location 111 is captured. The determination unit 50 determines that it is good if, for example, in the image, the luminance values in a range above a certain standard at the processing location 111 are within a predetermined range. 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, since the reflected light from the processing location 111 increases or decreases when a foreign object adheres to the processing location 111, an abnormality can be detected based on the luminance value of the location where the processing location 111 appears.

[0131] Further, the determination unit 50 may determine the quality of the processing of the processing location 111 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 it is good if, for example, in the image, the width of the processing location 111 is within a predetermined range.

[0132] Also, when the imaging device 10 is an imaging device for the two-color method, the determination unit 50 determines the quality of the processing of the processing location 111 based on, for example, the ratio between the luminance value of the processing location 111 when imaging is performed by detecting infrared rays in one wavelength range of two wavelength ranges and the luminance value of the processing location 111 when imaging is performed by detecting infrared rays in the other wavelength range of the two wavelength ranges. The determination unit 50 may use the ratio of the luminance values as it is for the 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 the determination. The determination unit 50 determines that it is good if, for example, the ratio of the luminance values of the processing location 111 or the calculated temperature in a range above a certain standard at the processing location 111 is within a predetermined range.

[0133] In addition, in Steps S11 and S12, instead of the operations described in Operation Example 1 of the imaging device 10, the operations described in any of Operation Examples 2 to 6 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 operations out of Operations Examples 1 to 6, and may select one control mode from the plurality of control modes based on a user's control mode selection instruction input to the input unit 30 or information regarding processing conditions from the laser processing machine 200. Thereby, the exposure conditions of the imaging device can be flexibly changed according to the purpose of laser processing or the like.

[0134] (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. However, 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 components in the embodiments are also included in the scope of the present disclosure.

[0135] For example, in the above embodiment, the control unit 20 starts the exposure of the imaging device 10 in synchronization with the start of the irradiation of the laser beam L on the processing location, but is not limited thereto. 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 on the processing location. In this case, for example, the laser processing machine 200 outputs a trigger indicating the timing of the start of the irradiation of the laser beam L to the control unit 20 before the start of the irradiation of the laser beam L. The time from the start of the exposure of the imaging device 10 to the start of the irradiation of the laser beam L is, for example, 1 second or less. The time from the start of the exposure of the imaging device 10 to the start of the irradiation of the laser beam L may be 100 milliseconds or less.

[0136] Also, for example, in the above embodiment, 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, but is not limited thereto. For example, 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.

[0137] Further, for example, in the above embodiment, the control unit 20 obtains a trigger indicating the timing of the start of the irradiation of the laser beam L from the laser processing machine 200 and starts the exposure of the imaging device 10 based on the trigger. However, the present invention is not limited to this. For example, the control unit 20 may output a signal for irradiating the laser processing machine 200 with the laser beam L after the time when the exposure of the imaging device 10 is started. Also by this, the control unit 20 can 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.

[0138] Further, for example, in the above embodiment, the control unit 20 determines the exposure time by adding a predetermined time Δt to the irradiation time of the laser beam L, 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. However, the present invention is not limited to this. For example, the control unit 20 may obtain a trigger indicating the timing of the end of the irradiation of the laser beam L from the laser processing machine 200 and end the exposure of the imaging device 10 after the end time of the irradiation of the laser beam L based on the trigger.

[0139] Further, the processing status monitoring system according to the present disclosure does not necessarily include all of the components described in the above embodiment, and may be configured only with the components for causing the target operation.

[0140] Further, 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.

[0141] 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 may be performed, or distributed processing may be performed.

[0142] In addition, in the above-described embodiment, the machining status monitoring system 100 may be implemented by a plurality of devices or as a single device. Further, when the machining status monitoring system 100 is implemented by a plurality of devices, each component included in the machining 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 machining status monitoring system 100 may be a part of another component. For example, in the machining status monitoring system 100, the control unit 20 may be provided in the imaging device 10 or in the laser processing machine 200.

[0143] 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 machining status monitoring method executed by a computer such as a control device, or as a control device that executes the machining status monitoring method. Also, the present disclosure may be implemented as a program for causing a computer to execute the machining status monitoring method, or as a computer-readable non-transitory recording medium storing such a program.

Industrial Applicability

[0144] The machining status monitoring system and the machining status monitoring method according to the present disclosure are useful for monitoring the machining status in laser processing.

Explanation of Signs

[0145] 10 Imaging device 15, 16A, 16B, 17 Images 20 Control unit 30 Input unit 40 Image acquisition unit 50 Determination unit 60 Storage unit 100 Processing status monitoring system 110, 110A, 110B, 110C Objects to be processed 111, 111A, 111B, 111C Processing locations 112 Transparent member 113 Absorbing member 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 portion of the workpiece, an imaging device that images the processing portion, and a control unit that controls the driving of the imaging device, wherein the control unit starts the exposure of the imaging device before the start time of the irradiation of the laser beam to the processing portion, and ends the exposure of the imaging device after the end time of the irradiation of the laser beam to the processing portion. 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 control unit starts the exposure of the imaging device at the start time. The processing status monitoring system according to Claim 1.

5. When the laser beam is irradiated a plurality of times to the same processing portion, the control unit starts the exposure of the imaging device before the start time of the irradiation of the laser beam to the processing portion in each of the plurality of times, and ends the exposure of the imaging device after the end time of the irradiation of the laser beam to the processing portion. The processing status monitoring system according to Claim 1.

6. The control unit causes the imaging device to image the processing portion under conditions where the gains are different from each other in each of the plurality of times. The processing status monitoring system according to Claim 5.

7. When the laser beam is irradiated a plurality of times to the same processing portion, In cases other than the last one among the multiple times, the control unit does not expose the imaging device during the time when the laser beam is irradiated to the processing location. In the last time, the exposure of the imaging device is started before the start time of the irradiation of the laser beam to the processing location, 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 processing status monitoring system according to claim 1.

8. 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.

9. 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.

10. The system further includes a determination unit that determines whether the processing of the processing location is good or bad based on an image captured by the imaging device of the processing location. The processing status monitoring system according to any one of claims 1 to 9.

11. 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 10.

12. 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 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. The processing status monitoring system according to claim 10.

13. A machining condition monitoring method for machining a workpiece by irradiating a laser beam while scanning a machining portion of the workpiece, and monitoring the machining condition using an imaging device that images the machining portion. Start the exposure of the imaging device before the start time of the irradiation of the laser beam to the machining portion. End the exposure of the imaging device after the end time of the irradiation of the laser beam to the machining portion. Machining condition monitoring method.

Images