KR102481078B1 - Evaluation apparatus, Evaluation method, and Display device - Google Patents

Abstract

An evaluation device for a laser device capable of detecting a malfunction in a simple manner without attaching a sensor to each part of the laser device.
The build-up time, which is the elapsed time from the start of excitation of the laser oscillator to the activation of the laser pulse, and the normal correspondence relationship with the pulse energy dependent physical quantity determined according to the pulse energy of the laser pulse are stored in the storage unit. Information indicating the starting point of excitation of the laser oscillator to be evaluated, and the measurement result of the time change of the light intensity of the laser pulse output from the laser oscillator to be evaluated are acquired by the data acquisition unit. The determination unit calculates the build-up time and the pulse energy-dependent physical quantity based on the information acquired from the data acquisition unit, compares the calculated value of the build-up time and the calculated value of the pulse energy-dependent physical quantity with the normal correspondence relationship, and evaluates Determine the normality of the operation of the target laser oscillator.

Description

Evaluation apparatus, evaluation method, and display device {Evaluation apparatus, evaluation method, and display device}

This application claims priority based on Japanese Patent Application No. 2018-012661 for which it applied on January 29, 2018. The entire content of that application is incorporated herein by reference.

The present invention relates to an evaluation device and evaluation method for evaluating the normality of a laser device, and a display device for displaying evaluation results of the laser device.

A laser processing device having a failure diagnosis function is known (for example, Patent Document 1). The laser processing device disclosed in Patent Document 1 below has a plurality of sensors for detecting the state of each part, and calculation means for deriving the operation state of each part from the outputs of the plurality of sensors. The plurality of sensors include a laser output sensor, a flow meter, a gas temperature sensor, a total reflection mirror temperature sensor, a bend mirror temperature sensor, a gas pressure sensor in a discharge tube, and the like. When the output of these sensors exceeds the normal range, it is determined that there is an abnormality in each part.

Patent Document 1: Japanese Unexamined Patent Publication No. 11-156570

In order to realize the conventional fault diagnosis function, a sensor must be attached to each part of the laser processing device. Further, even if the device as a whole is not operating normally, if the output of the sensor of each part is normal, such an abnormal state cannot be detected.

An object of the present invention is to provide an evaluation device and an evaluation method for a laser device capable of detecting a malfunction in a simple manner without attaching a sensor to each part of the laser device. Another object of the present invention is to provide a display device that notifies an operator of an operation abnormality in an easy-to-understand manner.

According to one aspect of the present invention,

A storage unit for storing a normal correspondence relationship between a build-up time, which is an elapsed time from the start of excitation of the laser oscillator to activation (or generation) of the laser pulse, and a physical quantity dependent on the pulse energy determined according to the pulse energy of the laser pulse;

a data acquisition unit that acquires information indicating the start point of excitation of the laser oscillator to be evaluated, and a measurement result of a change in light intensity of a laser pulse output from the laser oscillator to be evaluated;

Based on the information obtained from the data acquisition unit, the build-up time and the pulse energy-dependent physical quantity are calculated, and the calculated value of the build-up time and the pulse energy-dependent physical quantity are stored in the storage unit. An evaluation device having a determination unit for determining the normality of the operation of the laser oscillator, which is the object of evaluation, by comparing it with the normal correspondence relationship.

According to another aspect of the present invention,

An oscillation command signal is transmitted to the laser oscillator to be evaluated,

Detecting a laser pulse output from the laser oscillator to be evaluated,

Calculate a build-up time, which is an elapsed time from the oscillation command point by the oscillation command signal to the activation (or generation) of the laser pulse, and a pulse energy dependent physical quantity determined according to the pulse energy of the laser pulse,

By comparing the calculated value of the build-up time and the calculated value of the pulse energy-dependent physical quantity with a predetermined normal correspondence relationship between the build-up time and the pulse energy-dependent physical quantity, the steady state of the operation of the laser oscillator to be evaluated An evaluation method for determining is provided.

According to another aspect of the present invention,

The build-up time, which is the elapsed time from the start of excitation of the laser oscillator to the activation of the laser pulse, the normal correspondence relationship between the pulse energy dependent physical quantity determined according to the pulse energy of the laser pulse, and the laser pulse output from the laser oscillator to be evaluated A display device is provided that displays a correspondence between the calculated value of the build-up time obtained by detection and the calculated value of the pulse energy dependent physical quantity on a display screen.

It is possible to detect malfunctions in a simple manner without attaching sensors to each part of the laser device.

1 is a schematic diagram of a laser device as an evaluation target incorporating an evaluation device according to an embodiment.
Fig. 2 is a graph showing waveforms of an oscillation command signal S0 transmitted from a laser device controller to a laser oscillator and a detection signal S1 supplied from a photodetector to an evaluation device.
3 is a scatter diagram showing the relationship between the build-up time and the pulse energy-dependent physical quantity determined according to the pulse energy.
4 is a block diagram of an evaluation device according to an embodiment.
Fig. 5 is a front view of a display device displaying information indicating an abnormal state of operation of the laser device.
Fig. 6 is a flowchart showing procedures of a method for evaluating the normality of operation of a laser device according to an embodiment.

Referring to Figs. 1 to 6, an evaluation device and evaluation method of a laser device according to an embodiment will be described.

1 is a schematic diagram of a laser device as an evaluation target incorporating an evaluation device according to an embodiment. The laser oscillator 10 receives an oscillation command signal S0 from the controller 20 and outputs a pulsed laser beam. As the laser oscillator 10, various pulsed laser oscillators, for example, carbon dioxide laser oscillators that oscillate pulses can be used. The laser oscillator 10 includes an optical resonator, a discharge electrode, a discharge electrode driving circuit, and the like.

The pulsed laser beam output from the laser oscillator 10 passes through the first optical system 11, is reflected by the bending mirror 12, passes through the second optical system 13, and is supported by the stage 14. It enters the object (15). The object to be processed 15 is, for example, a printed wiring board, and punching is performed with a pulsed laser beam.

A part of the pulsed laser beam incident on the bending mirror 12 passes through the bending mirror 12 and is incident on the photodetector 21 . The photodetector 21 detects the incident laser pulse and outputs a detection signal S1 which is an electrical signal according to the light intensity of the laser pulse. As the photodetector 21, an infrared sensor having a response speed capable of following a change in pulse waveform, for example, a cadmium telluride mercury sensor (MCT sensor) or the like can be used.

The first optical system 11 includes a beam expander, an aspheric lens, and an aperture. The beam expander changes the beam diameter and divergence angle of the laser beam. An aspherical surface lens changes the beam profile from a Gaussian shape to a top flat shape. The aperture shapes the cross-sectional shape of the beam.

The second optical system 13 includes a beam scanner, an fθ lens, and the like. The beam scanner includes, for example, a pair of galvanometer mirrors, and scans a laser beam in a two-dimensional direction according to a command from the control device 20 . The fθ lens condenses the laser beam scanned by the beam scanner onto the surface of the object 15 to be processed. It is also possible to have a configuration in which the position of the aperture is reduced and projected onto the surface of the object 15 to be processed.

The stage 14 can support the object 15 on a horizontal support surface and move the object 15 in two directions in the horizontal plane. A controller 20 controls the movement of the stage 14 . For the stage 14, an XY stage is used, for example.

An evaluation device 30 evaluates the steady state of operation of the laser device based on the oscillation command signal S0 transmitted from the control device 20 and the detection signal S1 given from the photodetector 21. . The evaluation device 30 displays on the display device 26 an evaluation result of the steady state of operation of the laser device. Further, the evaluation device 30 issues a warning from the alert issuing device 25 when it is determined that there is an abnormality in the operation of the laser device.

Fig. 2 shows an oscillation command signal S0 transmitted from the controller 20 (Fig. 1) to the laser oscillator 10 (Fig. 1), and an evaluation device 30 (from the photodetector 21 (Fig. 1)). It is a graph showing the waveform of the detection signal (S1) given to FIG. 1).

When the oscillation command signal S0 starts (or is generated) at time t0, the laser oscillator 10 starts supplying high-frequency power to the discharge electrodes. By starting supply of high-frequency power to the discharge electrode, excitation of the laser medium of the laser oscillator 10 is started. That is, the activation of the oscillation command signal S0 corresponds to the oscillation command of the laser oscillator 10, and the starting point of the oscillation command signal S0 corresponds to the start of excitation of the laser oscillator 10.

The laser pulse starts at time t1 after a delay from time t0 at the start of excitation. Corresponding to the activation of the laser pulse, the detection signal S1 is also activated. The elapsed time from the time t0 at the start of excitation to the time t1 at the start of the laser pulse is referred to as the build-up time (t _BU ). At the starting point of the laser pulse, a peak waveform of extreme time due to gain switching appears, after which an approximately constant light intensity is maintained. A portion where a substantially constant light intensity is maintained is referred to as a main portion of the pulse waveform.

When the oscillation command signal S0 ends (or disappears) at time t2, the laser oscillator 10 stops supplying high frequency power to the discharge electrodes. If the supply of high-frequency power to the discharge electrode is stopped, the laser medium of the laser oscillator 10 is not excited. That is, the end of the oscillation command signal S0 means a command to stop the excitation of the laser oscillator 10. When the excitation of the laser oscillator 10 is stopped, the intensity of the laser pulse output from the laser oscillator 10 gradually decreases.

The time-integrated value of one pulse waveform of the detection signal S1 is determined according to the energy per pulse (pulse energy). In this specification, this integral value determined according to the pulse energy will be referred to as "pulse energy dependent physical quantity".

Since the time width of the peak waveform of the extreme time by gain switching is sufficiently short compared to the entire pulse width, the integral value of the part excluding the peak waveform of the extreme time by the gain switching from the pulse waveform is adopted as the pulse energy-dependent physical quantity. You can do it. Further, since the time width of the tail portion after excitation is stopped is sufficiently short compared to the pulse width of the laser pulse, and the light intensity of the tail portion rapidly decreases with the passage of time, the integral value of the pulse waveform excluding the tail portion is It may be employed as a pulse energy dependent physical quantity. In this way, the integral value of the principal part of the pulse waveform may be employed as the pulse energy dependent physical quantity.

The build-up time t _BU depends on the high-frequency power (excitation intensity) supplied to the discharge electrodes of the laser oscillator 10, and the build-up time t _BU decreases as the excitation intensity increases. The light intensity of the main part of the pulse waveform also depends on the excitation intensity, and as the excitation intensity increases, the light intensity of the main part of the pulse waveform increases. For this reason, the relationship between the build-up time t _BU and the pulse energy-dependent physical quantity shows a tendency that the pulse energy-dependent physical quantity decreases as the build-up time t _BU increases.

3 is a scatter diagram showing the relationship between the build-up time (t _BU ) and the pulse energy-dependent physical quantity determined according to the pulse energy. The horizontal axis represents the build-up time (t _BU ) in a linear scale, and the vertical axis represents the pulse energy dependent physical quantity determined according to the pulse energy in a linear scale. When the operation of the laser oscillator 10 is normal, the excitation intensity is changed within the range of the rated power of the laser oscillator 10 to collect data of the build-up time (t _BU ) and the pulse energy dependent physical quantity, and these data When plotted on a scatter plot, the plotted points fall within the range 50 representing normal correspondence. The range 50 representing the normal correspondence relationship represents an elongated shape along a straight line inclined in a direction in which the physical quantity dependent on the pulse energy decreases as the build-up time t _BU increases.

The position on the scatter diagram corresponding to the calculated value of the build-up time (t _BU ) and the calculated value of the pulse energy-dependent physical quantity obtained based on the pulse waveform obtained when there is an abnormality in the operation of the laser oscillator 10 has a normal correspondence relationship out of the indicated range (50).

When the position corresponding to the calculated value deviates in the direction in which the build-up time (t _BU ) is longer than the range 50 representing the normal correspondence relationship or in the direction in which the physical quantity dependent on the pulse energy is increased, the laser oscillator 10 oscillates It is assumed that there is something wrong with the mode. For example, it is suspected that the oscillation mode is a higher order mode.

If the position corresponding to the calculated value deviates in the direction in which the build-up time t _BU is shorter than the range 50 representing the normal correspondence relationship or in the direction in which the physical quantity dependent on the pulse energy is reduced, the first optical system 11 It is presumed that an abnormality has occurred in (Fig. 1). For example, a decrease in the transmittance of the optical component in the first optical system 11 is suspected. Also, an abnormality of the photodetector 21 itself is suspected.

When the position corresponding to the calculated value is located in a region where the range 50 showing the normal correspondence relationship is stretched in a direction in which the build-up time t _BU becomes longer and the physical quantity dependent on pulse energy decreases, the laser oscillator 10 ) is presumed to have occurred. For example, it is presumed that a decrease in the amplification degree and an increase in loss occur in the optical resonator of the laser oscillator 10. In this respect, misalignment of the optical resonator, abnormality of the excitation energy supply source, damage to the mirror constituting the optical resonator, and the like are suspected.

4 is a block diagram of an evaluation device 30 according to an embodiment. The evaluation device 30 includes a determination unit 31, a storage unit 32, a data acquisition unit 33, and a display control unit 34. The functions of the determination unit 31, the data acquisition unit 33, and the display control unit 34 are realized, for example, by a computer executing a program.

The storage unit 32 stores a normal correspondence relationship between the build-up time t _BU and the pulse energy dependent physical quantity. For example, the storage unit 32 stores a range 50 representing a normal correspondence relationship in a scatter plot (FIG. 3).

The data acquisition unit 33 acquires, from the controller 20, information indicating the excitation start point (time t0 in FIG. 2) of the laser oscillator 10 to be evaluated. For example, the data acquisition unit 33 acquires the startup time of the oscillation command signal S0 by detecting the startup of the oscillation command signal S0 input from the controller 20 . The startup time of the oscillation command signal S0 corresponds to information indicating the excitation start point. Further, the data acquisition unit 33 acquires the measurement result of the time change of the light intensity of the laser pulse output from the laser oscillator 10 by receiving the detection signal S1 from the photodetector 21 .

The determination unit 31 calculates the build-up time (t _BU ) and the pulse energy dependent physical quantity based on the information acquired by the data acquisition unit 33 . In addition, the calculated value of the build-up time t _BU and the calculated value of the pulse energy dependent physical quantity are compared with the normal correspondence stored in the storage unit 32 to determine the steady state of the laser pulse. Specifically, when the correspondence relationship between the calculated value of the build-up time (t _BU ) and the calculated value of the pulse energy-dependent physical quantity is not included in the normal correspondence relationship stored in the storage unit 32, an abnormality occurs in the laser pulse. determine that there is

More specifically, the determination unit 31 determines that the position on the scatter plot (FIG. 3) corresponding to the calculated value of the build-up time t _BU and the calculated value of the pulse energy dependent physical quantity is within the range 50 indicating a normal correspondence relationship. ), it is determined that there is an abnormality in the laser pulse. In addition, the determination unit 31 determines that the position on the scatter diagram (FIG. 3) corresponding to the calculated value of the build-up time t _BU and the calculated value of the pulse energy dependent physical quantity is inside the range 50 indicating a normal correspondence relationship. , it is determined that the laser pulse is normal.

The determination unit 31 obtains the frequency of appearance of the laser pulse determined to have an abnormality. The frequency of appearance is defined as, for example, the ratio of the number of abnormal laser pulses to the total number of laser pulses output within a predetermined period of time. If the frequency of appearance of abnormal laser pulses exceeds the threshold value, the determination unit 31 determines that there is an abnormality in the operation of the laser device.

Further, when determining that there is an abnormality in the operation of the laser device, the determination unit 31 operates the warning issuing device 25 to issue an alarm. For example, the alarm issuing device 25 is a speaker, and the determining unit 31 outputs an alarm sound from the speaker. Further, when determining that there is an abnormality in the operation of the laser device, the determination unit 31 transmits a command to display the abnormal state to the display control unit 34.

The display control unit 34 displays information indicating an abnormal state of operation of the laser device on the display device 26 based on a command from the determination unit 31 .

Fig. 5 is a front view of the display device 26 on which information indicating an abnormal state of operation of the laser device is displayed. A scatter plot in which the build-up time t _BU corresponds to one axis (horizontal axis) and the pulse energy-dependent physical quantity corresponds to the other axis (vertical axis) is displayed on the display screen of the display device 26 . In this scatter plot, a range 50 showing a normal correspondence relationship between the build-up time (t _BU ) and the pulse energy-dependent physical quantity is shown. In addition, a plurality of data consisting of the calculated value of the build-up time (t _BU ) obtained within the evaluation time and the calculated value of the pulse energy dependent physical quantity are plotted on the scatter chart. 5 shows an example in which most of the data is plotted above the range 50 representing the normal correspondence relationship (region where the pulse energy dependent physical quantity is large).

Further, information indicating an abnormal state is displayed in characters in an area other than the range 50 indicating the normal correspondence relationship of the scatter plot displayed on the display screen. For example, characters such as "oscillation mode abnormality", "optical system abnormality", and "oscillator internal abnormality" are displayed in the area in the scatter plot corresponding to the abnormality.

Fig. 6 is a flowchart showing procedures of a method for evaluating the normality of operation of a laser device according to an embodiment. Hereinafter, the evaluation method of the present embodiment will be described with reference to FIGS. 6 and 1 .

First, the controller 20 transmits an oscillation command signal S0 to the laser oscillator 10 (step ST1). The oscillation command signal S0 is also input to the evaluation device 30 . Based on the detection signal S1 from the photodetector 21, the evaluation device 30 detects the activation of the laser pulse and the pulse waveform (step ST2). The evaluation device 30 calculates the build-up time t _BU and the pulse energy dependent physical quantity based on the oscillation command signal S0 and the detection signal S1 (step ST3). Based on the calculation result, the steady state of the laser pulse is determined (step ST4). The procedures from step ST1 to step ST4 are repeated until the number of evaluated pulses reaches a predetermined number of pulses (step ST5).

When the number of pulses for which evaluation is completed reaches a predetermined number of pulses, the value for the number of pulses for which evaluation is completed is initially set. After that, the normality of the operation of the laser device is evaluated (step ST7). For example, the normality of the operation of the laser device is determined based on the frequency of appearance of the number of abnormal pulses. When the frequency of appearance of abnormal laser pulses exceeds the determination threshold, it is determined that there is an abnormality in the operation of the laser device.

If it is determined that there is an abnormality in the operation of the laser device, a process in case of an abnormality is executed (step ST8). For example, an alarm is issued, an abnormal state is displayed, and the like. After that, it is determined whether or not to end the laser processing process (step ST9). When it is judged that the operation of the laser device is normal, it is determined whether or not to end the laser processing process without executing the processing at the time of abnormality (step ST9).

When continuing the laser processing process, the process from step ST1 to step ST9 is repeatedly executed. The processing from step ST2 to step ST9 described above is executed by the evaluation device 30. For example, when the laser processing of the object 15 (FIG. 1) ends, the laser processing process ends. Alternatively, the operator may see the abnormal state displayed on the display device 26 (FIG. 5), and the laser processing process may be terminated by the operator's intervention.

Next, excellent effects obtained by adopting the configuration of the evaluation apparatus according to the above embodiment will be described.

In this embodiment, sensors are not attached to each part of the laser device, and based on the oscillation command signal S0 transmitted from the controller 20 and the detection signal S1 output from the photodetector 21, The normality of the operation of the laser device can be evaluated. The operator can intuitively grasp the operating state of the laser device by looking at the scatter plot (FIG. 5) displayed on the display device 26. For example, in the example shown in Fig. 5, it can be easily estimated that an abnormality in the oscillation mode has occurred in the laser oscillator 10.

Further, in the above embodiment, generation of an abnormal laser pulse can be detected in real time while performing laser processing of the object 15 (FIG. 1). If the period for calculating the frequency of occurrence of abnormal laser pulses is shortened, the abnormality of the laser device can be detected at an early stage.

Next, a modified example of the above embodiment will be described. In the above embodiment, when the frequency of occurrence of abnormal laser pulses exceeds the threshold value, an alarm is issued and the abnormal state is displayed on the display device 26. An upper limit value may be set above a threshold value for issuing an alarm, and laser processing may be automatically stopped when the frequency of occurrence of abnormal laser pulses exceeds the upper limit value. For this reason, the increase of defective products can be suppressed.

In the above embodiment, as shown in Fig. 1, the evaluation device 30 is provided separately from the control device 20, but the control device 20 may have the function of the evaluation device 30.

The present invention is not limited to the above-described embodiment. For example, it will be apparent to those skilled in the art that various changes, improvements, combinations, and the like are possible.

10 Laser Oscillator
11 1st optical system
12 bending mirror
13 2nd optical system
14 stage
15 Objects to be processed
20 Controls
21 photodetector
25 Alarm triggering device
26 display
30 evaluation device
31 Tribunal
32 storage unit
33 Data Acquisition Unit
34 display control unit
50 Range showing normal correspondence between build-up time (t _BU ) and pulse energy dependent physical quantity
S0 oscillation command signal
S1 detection signal

Claims (5)

a storage unit for storing a normal correspondence relationship between a build-up time, which is an elapsed time from start of excitation of the laser oscillator to start-up of the laser pulse, and a pulse energy dependent physical quantity determined according to the pulse energy of the laser pulse;
a data acquisition unit that acquires information indicating a start point of excitation of a laser oscillator to be evaluated and a measurement result of a change in light intensity of a laser pulse output from the laser oscillator to be evaluated;
Based on the information obtained from the data acquisition unit, the build-up time and the pulse energy-dependent physical quantity are calculated, and the calculated value of the build-up time and the pulse energy-dependent physical quantity are stored in the storage unit. An evaluation apparatus having a determination unit for determining the normality of the operation of the laser oscillator, which is the object of evaluation, by comparing it with the normal correspondence relationship. According to claim 1,
wherein the determination unit issues an alarm when a corresponding relationship between the calculated value of the build-up time and the calculated value of the pulse energy-dependent physical quantity is not included in the normal corresponding relationship stored in the storage unit. According to claim 1 or 2,
and a display control unit for displaying on a display device the normal correspondence stored in the storage unit and the correspondence between the calculated value of the build-up time and the calculated value of the pulse energy dependent physical quantity. An oscillation command signal is transmitted to the laser oscillator to be evaluated,
Detecting a laser pulse output from the laser oscillator to be evaluated,
Calculate a build-up time, which is an elapsed time from the oscillation command point by the oscillation command signal to the activation of the laser pulse, and a pulse energy dependent physical quantity determined according to the pulse energy of the laser pulse;
By comparing the calculated value of the build-up time and the calculated value of the pulse energy-dependent physical quantity with a predetermined normal correspondence relationship between the build-up time and the pulse energy-dependent physical quantity, the steady state of the operation of the laser oscillator to be evaluated Evaluation method for determining . delete

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