JP2023074668A - Laser processing device and laser processing method - Google Patents

Abstract

To provide a technique that is able to generate visible guide light by using a composing member for generating invisible laser light.SOLUTION: A CPU 41 performs processing laser emission steps (S12 to S18) in which, to perform a process on a to-be-processed object 7, a temperature of a THC crystal 125 is set to a first temperature by a temperature change unit 12a and a third harmonic wave is caused to radiate to be emitted to the to-be-processed object 7, thereby performing the process; and guide light emission processes (S22 to S28) in which, to emit guide light to the to-be-processed object 7, the temperature of the THG crystal 125 is set to a second temperature by the temperature change unit 12a to decrease efficiency in conversion to the third harmonic wave than that in the processing laser emission steps and a second harmonic wave is emitted to the to-be-processed object 7.SELECTED DRAWING: Figure 5

Description

The present application relates to a technique for laser processing an object.

Patent Literature 1 describes a laser surgical treatment apparatus that generates visible guide light for targeting the irradiated area in addition to invisible laser light for performing surgical treatment on the irradiated area. . Specifically, this laser surgical treatment device transmits the laser light in the optical path of the laser light with a wavelength of 1.06 μm output from the YAG laser device between the YAG laser device and the condensing lens. In addition, the nonlinear crystal of the harmonic generator for generating the second harmonic (wavelength 0.53 μm) as the guide light and the laser beam of high power to avoid damage to the eyes of the operator. A filter or beam splitter, for example, is provided to absorb or reflect the laser light off-axis and to pass only the second harmonic to the condenser lens.

JP-A-57-31853

However, the laser surgical treatment apparatus described in Patent Document 1 is configured by adding a component used only for generating visible guide light in addition to the component for generating invisible laser light. There is room for improvement.

An object of the present application is to provide a technique capable of generating visible guide light using a component that generates invisible laser light.

In order to achieve the above object, the laser processing apparatus of the present application is a laser processing apparatus that processes a work by irradiating a laser beam onto the work. a first nonlinear optical element that receives a fundamental laser beam and emits a first harmonic shorter than the wavelength of the fundamental laser beam; a second nonlinear optical element that emits a second harmonic having a wavelength shorter than that of the first harmonic; a temperature changing unit capable of changing the temperature of the second nonlinear optical element; and a control unit, When processing a workpiece, the temperature changing unit sets the temperature of the second nonlinear optical element to the first temperature, and emits the second harmonic to irradiate the workpiece to perform processing. When the laser irradiation process and the work are irradiated with the guide light, the temperature changer sets the temperature of the second nonlinear optical element to the second temperature to increase the conversion efficiency to the second harmonic. and a guide light irradiation process for irradiating the workpiece with the first harmonic, which is lowered from time to time.

According to the present application, it is possible to generate the first harmonic using a component that generates the second harmonic.

It is a figure which shows schematic structure of the laser processing part contained in the laser processing apparatus which concerns on one Embodiment of this application. 2 is a diagram showing a schematic configuration of a laser oscillation unit included in the laser processing section of FIG. 1; FIG. It is a block diagram which shows the control structure of the laser processing apparatus which concerns on one Embodiment of this application. 3 is a diagram showing an example of temperature versus power characteristics of an SHG crystal ((a)) and a THG crystal ((b)) included in the laser oscillation unit of FIG. 2; FIG. FIG. 4 is a flow chart showing a procedure of control processing executed by a controller in FIG. 3, particularly a CPU; FIG.

Hereinafter, embodiments of the present application will be described in detail with reference to the drawings. FIG. 1 shows a schematic configuration of a laser processing unit 3 included in a laser processing device 1 according to an embodiment of the present application, FIG. 2 shows a schematic configuration of a laser oscillation unit 12 included in the laser processing unit 3, and FIG. 3 shows the control configuration of the laser processing apparatus 1 . 1 to 3, a part of the basic configuration is omitted, and the dimensional ratios of the drawn parts are not necessarily accurate. Moreover, in FIG. 1, the vertical direction is as shown in the figure.

The laser processing apparatus 1 is composed of a PC 2 and a laser processing section 3, as shown in FIG. Since PC2 is a general PC, description of its configuration is omitted.

The laser processing unit 3 two-dimensionally scans the processing surface 8 of the processing object 7 with the processing laser beam P to perform marking (printing) processing.

The controller 6 is composed of a computer, and is connected to the PC 2 via, for example, USB, Ethernet, wireless LAN, RS-232C, etc. so as to be able to communicate bidirectionally. Controller 6
drives and controls the laser processing unit 3 based on the printing information, parameters, various instruction information and the like transmitted from the PC 2 .

As shown in FIG. 1, the laser processing section 3 includes a laser oscillation unit 12, a dichroic mirror 100, a power meter 110, a reflecting mirror 101, an optical system 70, a camera 103, a galvanometer scanner 18, an fθ lens 19, and the like. , is covered with a substantially rectangular parallelepiped housing cover (not shown).

The laser oscillation unit 12 is composed of a diode laser 120, a condenser lens 121, an end mirror 122, a laser crystal 123, a Q-switch 124, a THG crystal 125, an SHG crystal 126, an output coupler 127, etc., as shown in FIG. ing. Note that the components from the end mirror 122 to the output coupler 127 are integrated into one package in this embodiment.

The diode laser 120 emits pump light with a wavelength of, for example, 808 nm in this embodiment. The pump light emitted from the diode laser 120 is input along the optical axis L from the end face of the laser crystal 123 by the condenser lens 121 . The laser crystal 123 is composed of, for example, an Nd:YAG crystal, and the surface of the crystal is coated with a thin film that transmits approximately 100% of light with a wavelength of 1064 nm. The laser crystal 123 absorbs pump light with a wavelength of 808 nm and generates infrared light with a wavelength of 1064 nm. The light with a wavelength of 1064 nm generated by the laser crystal 123 is reflected by the output coupler 127 and the end mirror 122, becomes a beam with a wavelength of 1064 nm by reciprocating between the output coupler 127 and the end mirror 122, and enters the resonator. exists in

A pulse laser is generated by repeatedly storing and releasing energy in the laser crystal 123 by the Q-switch 124 . On the other hand, if the Q-switch 124 is permanently open, a CW-oscillated beam is produced. CW stands for "Continuous Wave"
is an abbreviation for A pulsed beam with a wavelength of 1064 nm generated by the Q-switch 124 is incident on the THG crystal 125 and the SHG crystal 126 . Here, THG is an abbreviation for "Third Harmonic Generation" and SHG is an abbreviation for "Second Harmonic Generation
is an abbreviation for That is, the THG crystal 125 means a third harmonic generation crystal, and the SHG crystal 126 means a second harmonic generation crystal. Specific examples of SHG crystals include LBO (Lithium Triborate, LiB3O5), BBO (β-barium borate, β-BaB2O4), and KTP (Potassium Titanyl Phosphate, KTiOPO4). Specific examples of THG crystals include LBO, BBO, KTP, and the like, like SHG crystals.

A beam with a wavelength of 1064 nm incident on the SHG crystal 126 is converted by the SHG crystal 126 into a beam with a wavelength of 532 nm, that is, a second harmonic wave, and this beam with a wavelength of 532 nm is incident on the output coupler 127 . The output coupler 127 transmits part of the incident beam with a wavelength of 532 nm and reflects the rest. The 532 nm wavelength beam reflected by the output coupler 127 is incident on the THG crystal 125 . A beam with a wavelength of 1064 nm is also incident on the THG crystal 125 from the Q-switch 124 . The THG crystal 125 generates and emits a beam with a wavelength of 355 nm, that is, the third harmonic based on the incident beam with a wavelength of 1064 nm and a beam with a wavelength of 532 nm. In addition, since the 1064 nm wavelength beam emitted from the Q-switch 124 is also incident on the output coupler 127, the output coupler 127 emits beams with wavelengths of 355 nm, 532 nm and 1064 nm. However, the power of the beam emitted from the output coupler 127 is different for each wavelength depending on the situation at the time of emission. Here, the beam with a wavelength of 355 nm is the processing laser beam P. As shown in FIG. The beam with a wavelength of 532 nm is used as guide light G, which will be described later, and the beam with a wavelength of 1064 nm is used for laser power measurement, which will be described later. Thus, the beam with a wavelength of 1064 nm is an example of "fundamental wave laser light" because it is the basis for generating the beams with wavelengths of 355 nm and 532 nm.

Returning to FIG. 1 , the output coupler 127 , that is, the beams of each wavelength emitted from the laser oscillation unit 12 are incident on the dichroic mirror 100 . The reflectance of the dichroic mirror 100 has wavelength dependence. Specifically, the dichroic mirror 100 is surface-treated with a dielectric multilayer film, and has high reflectance with respect to wavelengths of 355 nm and 532 nm. It is configured to be mostly transparent to the beam. Therefore, a beam with a wavelength of 1064 nm is supplied to power meter 110 .

The beams with wavelengths of 355 nm and 532 nm reflected by the dichroic mirror 100 are incident on the reflecting mirror 101 . The reflecting mirror 101 supplies the incident beams with a wavelength of 355 nm and a wavelength of 532 nm to the optical system 70 .

The optical system 70 has a first lens 72 , a second lens 74 and a moving mechanism 76 . In the optical system 70 , the 355 nm wavelength beam, ie, the processing laser beam P, which has passed through the reflecting mirror 101 , and the 532 nm wavelength beam, ie, the guide beam G, enter and pass through the first lens 72 . At that time, the light diameters of the processing laser light P and the guide light G are reduced by the first lens 72 . The processing laser light P and the guide light G that have passed through the first lens 72 enter and pass through the second lens 74 . At that time, the processing laser beam P and the guide beam G are collimated by the second lens 74 . The moving mechanism 76 includes an optical system motor 80 and a rack and pinion (not shown) that converts the rotational motion of the optical system motor 80 into linear motion. lens 74 is moved in the path direction of the processing laser beam P and the guide beam G. As shown in FIG. Here, the guide light Q is two-dimensionally scanned to form, for example, an image of a printing pattern to be marked (printed) by the processing laser beam P (hereinafter referred to as an "object"), a rectangle surrounding the object, and a , etc. are drawn on the processing surface 8 of the processing object 7 as a trajectory (time afterimage of scattered reflected light). That is, since it is necessary to use visible coherent light as the guide light Q, green laser light with a wavelength of 532 nm is used. The guide light Q does not require marking (printing) ability. 1 indicates the optical axis 10 of the processing laser beam P and the guide beam Q. In FIG. Furthermore, the direction of the optical axis 10 indicates the path direction of the processing laser beam P and the guide beam Q. As shown in FIG.

The galvanometer scanner 18 two-dimensionally scans the processing laser light P and the guide light G that have passed through the optical system 70 . In the galvano scanner 18, a galvano X-axis motor 31 and a galvano Y-axis motor 32 are mounted so that their respective motor shafts are perpendicular to each other, and scanning mirrors 18X and 18Y mounted on the tips of the respective motor shafts are arranged inside. facing each other. By rotating the scanning mirrors 18X and 18Y by controlling the rotation of the motors 31 and 32, the processing laser light P and the guide light G are two-dimensionally scanned. The two-dimensional scanning directions are the X direction and the Y direction.

The f.theta. Therefore, the processing laser light P and the guide light G are two-dimensionally scanned in the X direction and the Y direction on the processing surface 8 of the processing object 7 by controlling the rotation of the motors 31 and 32 .

The processing laser light P and the guide light G have different wavelengths. Therefore, when the distance between the first lens 72 and the second lens 74 in the optical system 70 is constant, the position where the processing laser light P and the guide light G converge (hereinafter referred to as "focus position F"). ) will be different in the vertical direction. Therefore, the focal position F of the processing laser light P and the guide light G is adjusted to the processing surface of the processing object 7 by adjusting the distance between the first lens 72 and the second lens 74 in the optical system 70. Fits on 8.

Similarly, when the position of the processing surface 8 of the object 7 is different in the vertical direction, the focal positions F of the processing laser light P and the guide light G are the same as those of the first lens 72 and the second lens 72 in the optical system 70 . By adjusting the distance between the lens 74 of the .

The camera 103 is provided near the f.theta. Thereby, the camera 103 picks up an image of the guide light G irradiated onto the processing surface 8 of the processing object 7, for example, and displays it, for example, on the liquid crystal display (not shown) of the PC 2, and displays it as an image to be processed from now on. The user may be able to check whether the alignment with the workpiece 7 is appropriate.

Next, the control configuration of the laser processing section 3 that constitutes the laser processing apparatus 1 will be described with reference to FIG.

As shown in FIG. 3, the laser processing unit 3 includes a controller 6, a galvano driver 36, a laser driver 37, an optical system driver 78, a camera 103, a laser oscillation unit 12, a power meter 110, an A/D converter 112, and the like. It is

The controller 6 controls the entire laser processing section 3 . The controller 6 is electrically connected to the galvanometer driver 36 , the laser driver 37 , the optical system driver 78 and the like, which constitute the laser processing section 3 . An external PC 2 is connected to the controller 6 and the camera 103 so as to be able to communicate bidirectionally. The controller 6 receives each piece of information (
For example, printing information, parameters for the laser processing unit 3, various instruction information from the user, etc.) can be received. The camera 103 is configured to be able to receive each piece of information (for example, image capturing instruction information, etc.) transmitted from the PC 2 and is configured to be able to transmit captured images to the PC 2 .

The controller 6 includes a CPU 41, a RAM 42, a ROM 43, a galvanometer controller 35, a laser controller 34, and the like. The CPU 41 is an arithmetic device and a control device for controlling the laser processing unit 3 as a whole. The CPU 41, RAM 42, ROM 43, etc. are connected to each other by a bus (not shown) to exchange data with each other.

The RAM 42 is for temporarily storing various calculation results calculated by the CPU 41, printing pattern (XY coordinate) data, and the like.

The ROM 43 stores various programs, for example, programs for control processing, which will be described later with reference to FIG. 5, and the like. In addition to this control processing program, the various programs include, for example, various delay values, the thickness, depth and number of print patterns corresponding to print information input from the PC 2, the laser oscillation unit 12 A program or the like for storing various parameters indicating the laser output, the laser pulse width of the processing laser beam P, the scanning speed of the processing laser beam P by the galvanometer scanner 18, the scanning speed of the guide light G by the galvanometer scanner 18, etc. in the RAM 42. be. Further, the ROM 43 stores parameters for distortion correction and status information (error information, number of times of processing, processing time, etc.) of the galvanometer scanner 18 and the laser processing device 1 .

The CPU 41 performs various calculations and controls based on various programs stored in the ROM 43 .

The CPU 41 outputs to the galvano controller 35 processing data, the speed of scanning the guide light G by the galvano scanner 18 , galvano scanning speed information indicating the speed of scanning the processing laser beam P by the galvano scanner 18 , and the like. The CPU 41 also outputs laser driving information indicating the laser output of the laser oscillation unit 12 set based on the processing data, the laser pulse width of the processing laser beam P, and the like to the laser driver 37 .

The galvano controller 35 calculates the drive angle, rotational speed, etc. of the galvano X-axis motor 31 and the galvano Y-axis motor 32 based on each information (for example, processing data, galvano scanning speed information, etc.) input from the CPU 41. , and outputs motor drive information indicating the drive angle and rotation speed to the galvano driver 36 . The galvano driver 36 drives and controls the galvano X-axis motor 31 and the galvano Y-axis motor 32 based on the motor drive information input from the galvano controller 35 to two-dimensionally scan the processing laser beam P and the guide beam G. FIG.

The laser driver 37 drives the laser oscillation unit 12 based on the laser output of the laser oscillation unit 12 input from the controller 6 and the laser drive information indicating the laser pulse width of the processing laser beam P and the like.

The laser oscillation unit 12 is provided with a temperature changer 12a. The temperature changer 12a can change each temperature of the SHG crystal 126 and the THG crystal 125 independently. FIG. 4(a) shows an example of the temperature versus power characteristics (conversion efficiency) of the second harmonic generated by the SHG crystal 126, and FIG. 4(b) shows the temperature of the third harmonic generated by the THG crystal 125. An example of power vs. power characteristics (conversion efficiency) is shown. The temperature changing unit 12a changes the respective temperatures of the SHG crystal 126 and the THG crystal 125 so as to appropriately change the respective powers of the second and third harmonic waves generated by the SHG crystal 126 and the THG crystal 125. I have to. The purpose and method of the change will be described later with reference to FIG. As can be seen from the temperature-to-power characteristics in FIGS. 4A and 4B, each power characteristic fluctuates significantly with a change of 1° C. Therefore, the temperature changing unit 12a can perform fine temperature changes. It is necessary to use a device that can Specifically, a thermal control module such as a Peltier element or a combination of a heater and a heat sink is provided in the SHG crystal 126 and the THG crystal 125, each having a temperature sensor and a thermal control module depending on the output of each temperature sensor. One having a control section (control IC) for controlling the amount of current to flow can be mentioned.

The optical system driver 78 drives and controls the optical system motor 80 based on the information input from the controller 6 to move the second lens 74 .

The power meter 110 has, for example, a structure including a photodetector such as a photodiode sensor, and outputs an analog voltage value corresponding to the intensity of the incident beam with a wavelength of 1064 nm. The A/D converter 112 is provided on the output side of the power meter 110 and converts the analog voltage value output by the power meter 110 into a digital value. The A/D converter 112 is connected with the controller 6 . Therefore, the PC 2 can read the output voltage value of the power meter 110 output by the A/D converter 112 via the controller 6 . The power sensor may be a so-called thermal power sensor that utilizes the thermoelectric effect.

Control processing executed by the laser processing apparatus 1 configured as described above will be described in detail with reference to FIGS. 4 and 5. FIG. FIG. 5 shows the procedure of control processing executed by the controller 6, especially the CPU 41. As shown in FIG. This control process is started, for example, when the CPU 41 receives a laser enable signal for operating the laser oscillation unit 12 . Henceforth, in description of the procedure of each process, a step is described with "S".

In FIG. 3, the CPU 41 first determines whether or not the processing laser light mode has been selected (S10). In this embodiment, as the operation mode of the laser processing unit 3, the user can select one of processing laser light mode, guide light mode, laser power measurement mode, and other modes. The selection operation is performed via the PC2, for example.

In the judgment of S10, if the processing laser light mode is selected (S10: YES), the CPU 41 instructs the temperature changer 12a to set the SHG crystal 126 to a predetermined temperature (S12). The predetermined temperature is the temperature at which the power of the beam with a wavelength of 532 nm emitted from the SHG crystal 126 is maximized, which is temperature Ta in FIG. 4A, which is approximately 50.5.degree. Note that the predetermined temperature may be a predetermined temperature range instead of the temperature at one point. For example, the temperature is controlled within a temperature range in which the output value of the beam power falls within a fluctuation range of 0.5%, with the temperature Ta (approximately 50.5° C.) at which the power of the beam with a wavelength of 532 nm is maximized as the central value. can be anything.

Next, the CPU 41 instructs the temperature changer 12a to set the THG crystal 125 to the first temperature (S14). The first temperature is the temperature at which the power of the beam with a wavelength of 355 nm emitted from the THG crystal 125 is maximized, which is temperature Tb1 in FIG. This first temperature also corresponds to the wavelength 355 emitted from the THG crystal 125.
A width may be provided, such as a temperature range including the temperature at which the power of the nm beam is maximized. For example, with the temperature Tb1 (approximately 69.5° C.) at which the power of the beam with a wavelength of 355 nm becomes maximum as the central value, the temperature is controlled within a temperature range in which the output value of the beam power falls within a fluctuation range of 0.5%. can be anything.

Next, the CPU 41 sets the control of the Q-switch 124 to pulse oscillation (S16
), the excitation of the laser oscillation unit 12 is started (S18), and then the control process is terminated. As a result, the processing laser beam P having a wavelength of 355 nm is emitted from the laser processing unit 3 .

On the other hand, when the processing laser light mode is not selected in the determination of S10 (S10: NO), the CPU 41 determines whether or not the guide light mode is selected (S20). In this determination, if the guide light mode is selected (S20: YES), the CPU 41 instructs the temperature changer 12a to set the SHG crystal 126 to a predetermined temperature, as in the processing of S12 above. (S22).

Next, the CPU 41 instructs the temperature changer 12a to set the THG crystal 125 to the second temperature (S24). Here, the second temperature is a temperature separated from the first temperature by a predetermined temperature, and in FIG. °C. The temperature Tb1 is the temperature at which the power of the beam with a wavelength of 355 nm emitted from the THG crystal 125 is maximized, as described above. On the other hand, the temperature Tb2 is the temperature when the power of the beam with a wavelength of 355 nm emitted from the THG crystal 125 is reduced by 50% or more from the maximum value. In the example of FIG. 4B, the maximum power of the beam with a wavelength of 355 nm at the temperature Tb1 is approximately 5.5 W, so the power of the beam when it is reduced by 50% is approximately 2.75. The temperature is approximately 70.8° C., and the difference from the temperature Tb1 is 1.3° C., but it is set to 2° C. with a margin. Note that the second temperature is also the THG crystal 125
A temperature range may be provided, such as a temperature range including the temperature at which the power of the beam with a wavelength of 355 nm emitted from is reduced by 50% or more from the maximum value. For example, a temperature (approximately 71.5°C) that is two degrees higher than the temperature Tb1 at which the power of the beam with a wavelength of 355 nm becomes maximum
may be used as the central value, and the temperature may be controlled within a temperature range in which the output value of the beam power falls within a fluctuation range of 0.5%.

Next, the CPU 41 sets the control of the Q-switch 124 to CW oscillation (S26), starts excitation of the laser oscillation unit 12 (S28), and then terminates the control process. As a result, the guide light Q with a wavelength of 532 nm is emitted from the laser processing unit 3 . At this time, since the control of the Q-switch 124 is set to CW oscillation, the guide light Q is a CW-oscillated beam as described above and satisfies the predetermined safety standards. As a result, the guide light Q does not damage the operator's eyes or the like. When the guide light Q is output, instead of setting the control of the Q-switch 124 to CW oscillation, the power of the beam with a wavelength of 1064 nm on which the guide light Q is based may be reduced. good. Furthermore, a mechanism is added to place a filter that attenuates or reflects ultraviolet light (laser light of 355 nm) on the optical path 10 of the processing laser light P and the guide light G only when the guide light mode is selected, Control may be performed so that excessive ultraviolet laser light is not output from the laser processing unit 3 . Preferably, the second temperature and the base wavelength of 1064 nm are adjusted so that the output of the guide light Q with a wavelength of 532 nm is 390 μW or less, and the output of the ultraviolet laser light with a wavelength of 355 nm is 7.9 μW or less. It is better to adjust the power of the beam or install an ultraviolet light filter.

On the other hand, if the guide light mode has not been selected in the determination of S20 (S20: NO), the CPU 41 determines whether or not the laser power measurement mode has been selected (S30). In this determination, if the laser power measurement mode is selected (S30: YES), the CPU 41 executes the same processes as those of S12 to S18 (S32). As a result, the processing laser beam P having a wavelength of 355 nm is emitted from the laser processing unit 3 .

Next, the CPU 41 acquires the output value of the power meter 110 via the A/D converter 112 (S34). Then, the CPU 41 acquires the current temperature of the THG crystal 125 from the temperature changer 12a (S36). Further, the CPU 41 uses the acquired power meter 11
Based on the output value of 0, the conversion efficiency of the THG crystal 125 at the current temperature, and the conversion efficiency of the SHG crystal 126 controlled to the optimum temperature Ta, the power of the beam with a wavelength of 355 nm emitted from the THG crystal 125 was calculated. (S38) After that, the control process is terminated. The calculated power of the beam with a wavelength of 355 nm is transmitted to the PC 2 by the CPU 41 and displayed on the liquid crystal display of the PC 2, for example.

On the other hand, in the judgment of S30, if the laser power measurement mode is not selected (S30: NO), the CPU 41 assumes that the other mode is selected, executes other processing (S40), and then terminates the control processing. do.

In this embodiment, a laser beam with a wavelength of 1064 nm is used as the fundamental wave laser beam, and laser beams with a wavelength of 532 nm and a wavelength of 355 nm, which are second and third harmonics thereof, are generated. This is because the laser light with a wavelength of 532 nm, which is the second harmonic, is the visible light, and the laser light with a wavelength of 355 nm, which is the third harmonic, has a large power. In other words, if the third harmonic is the visible light, there is no need to use the second harmonic as the guide light Q. Further, as the processing laser beam P, a laser beam having a fourth harmonic or higher may be used. The fourth harmonic is generated by causing the fundamental wave laser beam to enter the SHG crystal 126 and then causing the second harmonic generated by the SHG crystal 126 to enter the SHG crystal 126 . Furthermore, the fundamental wave laser light is not limited to the laser light with a wavelength of 1064 nm, and laser light with other wavelengths may be used. In short, it suffices if the guide light Q, which is the visualization light, can be generated in the process of generating the processing laser light P from the fundamental wave laser light.

In the present embodiment, the laser light incident on the power meter 110 is a laser light with a wavelength of 1064 nm, which is a fundamental wave laser light. You may make it inject a part. In this case, when the guide light mode is selected and a laser beam with a wavelength of 532 nm is emitted from the laser oscillation unit 12, for example, a beam splitter is used instead of the dichroic mirror 100 to partially transmit the laser beam with a wavelength of 532 nm. and lead it to the power meter 110 , and the other half to the reflecting mirror 101 .

As described above, the laser processing apparatus 1 of the present embodiment is a laser processing apparatus 1 that processes the processing object 7 by irradiating the processing object 7 with a laser beam, and is a laser that oscillates a fundamental wave laser beam. The oscillation unit 12, the SHG crystal 126 that receives the fundamental laser light from the laser oscillation unit 12 and emits a second harmonic shorter than the wavelength of the fundamental laser light, and the fundamental laser light and the second harmonic. , a THG crystal 125 for emitting a third harmonic having a shorter wavelength than the second harmonic, a temperature changer 12 a capable of changing the temperature of the THG crystal 125 , and a CPU 41 . Then, when processing the object 7, the CPU 41 sets the temperature of the THG crystal 125 to the first temperature by the temperature changer 12a and emits the third harmonic to irradiate the object 7. and a processing laser irradiation process (S12 to S18) for performing processing, and when the guide light is irradiated to the processing object 7, the temperature of the THG crystal 125 is set to the second temperature by the temperature changing unit 12a to the third temperature. A guide light irradiation process (S22 to S28) is performed to irradiate the workpiece 7 with the second harmonic while reducing the conversion efficiency to higher harmonics than during the processing laser irradiation process.

As described above, in the laser processing apparatus 1 of the present embodiment, a component that generates the third harmonic is used, and only by changing the temperature of the THG crystal 125 included in the component, the guide light Q of the second harmonic is generated. can be generated. Thereby, the guide light Q can be generated while suppressing the manufacturing cost. In addition, switching between the processing laser beam P of the third harmonic and the guide beam Q of the second harmonic is performed only by changing the temperature of the THG crystal 125, so switching between them can be performed quickly. Furthermore, since the members used to generate only the guide light Q are unnecessary, adjustment of members related to the guide light Q and generation of the generated guide light Q, which were necessary when assembling the laser processing apparatus 1, are not required. No correction is required.

Incidentally, in the present embodiment, the workpiece 7 is an example of a "workpiece". The laser oscillation unit 12 is an example of a "laser oscillation section". The second harmonic is an example of a "first harmonic." The SHG crystal 126 is an example of the "first nonlinear optical element". The THG crystal 125 is an example of the "second nonlinear optical element". The third harmonic is an example of a "second harmonic." The first temperature is an example of "first temperature." The second temperature is an example of "second temperature".

The second harmonic wave is a double wave of the fundamental laser beam, and the third harmonic wave is a wave with a frequency three times or more that of the fundamental laser beam.

The fundamental laser light is infrared laser light (wavelength 1064 nm), the second harmonic is green laser light (wavelength 532 nm), and the third harmonic is ultraviolet laser light (wavelength 355 nm). As a result, the guide light Q, which is the second harmonic, becomes visible light and can play the role of guide light. Furthermore, the green laser light has better visibility than the red laser light that has been used as the guide light Q in the past.

The first temperature is the temperature at which the conversion efficiency of the THG crystal 125 is maximized, and the second temperature is 2° C. or more higher than the temperature at which the conversion efficiency is maximized. As a result, the second temperature deviates from the first temperature, which is the temperature at which the conversion efficiency of the THG crystal 125 is maximized. is extremely small compared to the power of the guide light Q. In addition, since it only takes about 10 seconds to raise the temperature of the THG crystal 125 by 2° C., the guide light Q is actually output after the switching from the processing laser light mode to the guide light mode is instructed. Waiting time is not long.

The first temperature is the temperature at which the conversion efficiency of the THG crystal 125 is maximized, and the second temperature is the temperature at which the conversion efficiency drops from the maximum by 50% or more. As a result, the second temperature is a temperature at which the conversion efficiency of the THG crystal 125 is lowered by 50% or more from the maximum. The power is extremely small compared to the power of the guide light Q.

Further, the CPU 41 reduces the output of the fundamental wave laser light from the laser oscillation unit 12 when irradiating the workpiece 7 with the guide light. As a result, the guide light Q satisfies the predetermined safety standards, so there is no danger that the guide light Q will damage the operator's eyes or the like.

The laser processing apparatus 1 further includes a dichroic mirror 100, which is an optical system that guides the laser light that has passed through the THG crystal 125 to an exit port, and transmits at least one of the fundamental laser light and the second harmonic. and a power meter 110 having a light receiving section and capable of measuring the output value of at least one of the transmitted fundamental laser light and the second harmonic guided to the light receiving section by the dichroic mirror 100. I have. Then, the CPU 41 further executes third harmonic output calculation processing (S38) for calculating the output of the third harmonic based on the output value of the power meter 110 and the temperature of the THG crystal 125. FIG. The fundamental wave laser light is unnecessary light in both the processing laser light mode and the guide light mode, and the second harmonic is light unnecessary in the guide light mode. Such unnecessary light is detected by the power meter 110, and the output of the third harmonic is calculated based on the detected output value of the power meter 110. Therefore, even if part of the third harmonic is not used, The output of the 3rd harmonic can be calculated, so that all the 3rd harmonic can be used for the processing laser beam P. FIG.

It should be noted that the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention.

(1) In the above embodiment, beams with wavelengths of 355 nm, 532 nm, and 1064 nm were generated using the THG crystal 125, SHG crystal 126, and laser crystal 123, respectively. It may be generated using a nonlinear optical element such as.

(2) In the above embodiment, the THG crystal 125, the SHG crystal 126, and the temperature changer 12a are integrated into one package, but the present invention is not limited to this, and independent packages may be used.

(3) In the above embodiment, in FIG. 4B, the temperature at which the power of the beam with a wavelength of 355 nm emitted from the THG crystal 125 drops by 50% or more from the maximum value is the temperature Tb2, that is, the THG crystal 125 The temperature was set to be 2° C. higher than the temperature Tb1 at which the power of the beam with a wavelength of 355 nm emitted from the laser becomes maximum. However, as can be seen from FIG. 4(b), the temperature when the power of the beam with a wavelength of 355 nm emitted from the THG crystal 125 is reduced by 50% or more from the maximum value is not only higher than the temperature Tb1, Since it also exists on the low temperature side, a temperature that is 2° C. low may be set instead of the temperature that is 2° C. high. Also, on the low temperature side, a range may be provided, such as a temperature range including the temperature at which the power of the beam with a wavelength of 355 nm is reduced by 50% or more from the maximum value. Furthermore, the set temperature may be different between the high temperature side and the low temperature side.

DESCRIPTION OF SYMBOLS 1... Laser processing apparatus, 2... PC, 3... Laser processing part, 12... Laser oscillation unit, 12a... Temperature change part, 41... CPU, 100... Dichroic mirror, 110... Power meter, 112... A/D converter, 120... Diode laser, 121... Condensing lens, 122... End mirror, 123... Laser crystal, 124... Q-switch, 125... THG crystal, 126... SHG crystal, 127... Output coupler.

Claims (9)

A laser processing apparatus for processing the work by irradiating the work with a laser beam,
a laser oscillator that oscillates a fundamental wave laser beam;
a first nonlinear optical element that receives the fundamental laser beam from the laser oscillation unit and emits a first harmonic shorter than the wavelength of the fundamental laser beam;
a second nonlinear optical element that receives the fundamental laser beam and the first harmonic and emits a second harmonic having a shorter wavelength than the first harmonic;
a temperature changer capable of changing the temperature of the second nonlinear optical element;
a control unit;
with
The control unit
When the workpiece is processed, the temperature of the second nonlinear optical element is set to the first temperature by the temperature changer, and the second harmonic is emitted to irradiate the workpiece for processing. Processing laser irradiation treatment to be performed,
When irradiating the workpiece with the guide light, the temperature changing unit sets the temperature of the second nonlinear optical element to a second temperature, and the conversion efficiency to the second harmonic is changed by the processing laser irradiation process. a guide light irradiation process for irradiating the work with the first harmonic, which is lowered from time to time;
A laser processing device characterized by executing the first harmonic is a second harmonic of the fundamental laser beam;
2. The laser processing apparatus according to claim 1, wherein the second harmonic is a wave having a frequency three times or more that of the fundamental laser beam. The basic laser light is an infrared laser light,
The first harmonic is green laser light,
2. The laser processing apparatus according to claim 1, wherein said second harmonic is ultraviolet laser light. 4. The laser processing apparatus according to claim 1, wherein said second temperature is higher than said first temperature. The first temperature is a temperature at which the conversion efficiency of the second nonlinear optical element is maximized,
5. The laser processing apparatus according to claim 4, wherein the second temperature is higher by 2[deg.] C. or more than the temperature at which the conversion efficiency is maximized. The first temperature is a temperature at which the conversion efficiency of the second nonlinear optical element is maximized,
5. The laser processing apparatus according to claim 4, wherein the second temperature is a temperature at which the conversion efficiency decreases by 50% or more from the maximum. 7. The control unit according to any one of claims 1 to 6, wherein the control unit reduces an output of the fundamental wave laser beam from the laser oscillation unit when irradiating the work with the guide light. laser processing equipment. The laser processing device further includes
An optical system for guiding the laser light that has passed through the second nonlinear optical element to an exit port, the optical system having a dichroic mirror that transmits at least one of the fundamental laser light and the first harmonic. and,
a power meter having a light receiving portion and capable of measuring an output value of at least one of the transmitted fundamental laser light and the first harmonic guided to the light receiving portion by the dichroic mirror;
with
The control unit further
2. A second harmonic output calculation process for calculating a second harmonic output based on the output value of said power meter and the temperature of said second nonlinear optical element is executed. 8. The laser processing apparatus according to any one of items 1 to 7. A laser processing apparatus for irradiating a work with a laser beam to process the work, comprising: a laser oscillation unit that oscillates a fundamental wave laser beam; a first nonlinear optical element that emits a first harmonic shorter than the wavelength of a laser beam; A laser processing method using a laser processing apparatus comprising a second nonlinear optical element that emits a second harmonic and a temperature changing unit capable of changing the temperature of the second nonlinear optical element,
When the workpiece is processed, the temperature of the second nonlinear optical element is set to the first temperature by the temperature changer, and the second harmonic is emitted to irradiate the workpiece for processing. Processing laser irradiation treatment to be performed,
When irradiating the workpiece with the guide light, the temperature changing unit sets the temperature of the second nonlinear optical element to a second temperature, and the conversion efficiency to the second harmonic is changed by the processing laser irradiation process. a guide light irradiation process for irradiating the work with the first harmonic, which is lowered from time to time;
A laser processing method comprising:

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