WO2022230045A1

WO2022230045A1 - Laser device, and laser processing device

Info

Publication number: WO2022230045A1
Application number: PCT/JP2021/016768
Authority: WO
Inventors: 弘菊池; 望平山; 秀則深堀
Original assignee: 三菱電機株式会社
Priority date: 2021-04-27
Filing date: 2021-04-27
Publication date: 2022-11-03

Abstract

A laser device (10) comprises a laser light source (11), a laser control unit (12), a wavelength converting element (13), and a temperature control unit (16). The laser light source (11) generates first-wavelength laser light (L1). The laser control unit (12) controls the laser light source (11) on the basis of laser control information, which is information relating to the control of the laser light source (11). The wavelength converting element (13) converts the first-wavelength laser light (L1) into second-wavelength laser light (L2) having a wavelength of 400 nm or less. The temperature control unit (16): acquires the laser control information for a second segment prior to a change time point of an output of the first-wavelength laser light (L1) in the second segment, wherein the second segment is a time segment in which a specific output is constant and is a time segment after a first segment, being a time segment before a change time point at which the specific output changes, and wherein the specific output is an output, from among the output of the first-wavelength laser light (L1), that contributes to the wavelength conversion to the second-wavelength laser light (L2); and controls a temperature of the wavelength converting element (13) in the second segment on the basis of the acquired laser control information for the second segment.

Description

Laser equipment and laser processing equipment

The present disclosure relates to a laser device and a laser processing device that wavelength-convert and output laser light from a laser light source.

In Patent Document 1, in order to maintain the temperature of the wavelength conversion crystal at the temperature with the highest conversion efficiency, it is possible to adjust the output power fluctuation of a laser of a specific wavelength to be wavelength-converted so that the response is similar to that of light output power fluctuation. A wavelength conversion method is disclosed in which a high-speed temperature control device is locally used to enable high-speed temperature control equivalent to laser output fluctuations.

Specifically, in the wavelength conversion method described in Patent Document 1, first, a first temperature control step is performed in which a temperature control device is used to control the temperature of the wavelength conversion element. Then, in order to cope with temperature fluctuations of the wavelength conversion element and obtain a high-power wavelength converted output, auxiliary light in a wavelength range that does not contribute to wavelength conversion is irradiated from the auxiliary light source to the working region to supply heat to the wavelength conversion element. A second temperature control step is performed. Then, based on the amount of heat supplied to the wavelength conversion element in the first temperature adjustment step and the amount of heat supplied to the wavelength conversion element in the second temperature adjustment step, the temperature of the wavelength conversion element is assisted to reach the target temperature. A temperature control step is performed to control the amount of heat absorbed from the light source.

JP 2018-159896 A

However, in the wavelength conversion method described in Patent Document 1, it is necessary to separately prepare an auxiliary light source, and it is also necessary to correct the deviation of the optical axis between the auxiliary light and the laser light of the specific wavelength. This complicates the configuration of the laser device having the wavelength conversion element. In addition, there is a problem that temperature control cannot follow the output change of the laser light of the specific wavelength when the output change of the laser light of the specific wavelength occurs in a short period of time or the output fluctuation range is large. In other words, in the wavelength conversion method described in Patent Document 1, when the output of laser light with a specific wavelength changes greatly in a short period of time, there is a problem that the output of the wavelength-converted laser light fluctuates or decreases. was there. In addition, there is a problem that the configuration of the laser device becomes complicated when trying to avoid such output fluctuations, output reduction, and the like.

The present disclosure has been made in view of the above, and the wavelength-converted laser light can be output without complicating the device configuration when the output of the laser light with a specific wavelength changes greatly in a short time. It is an object of the present invention to obtain a laser device capable of avoiding output fluctuation, output decrease, and the like.

A laser device according to the present disclosure includes a laser light source, a laser control section, a wavelength conversion element, and a temperature control section in order to solve the above-described problems and achieve the object. The laser light source generates laser light of a first wavelength. The laser control unit controls the laser light source based on laser control information, which is information regarding control of the laser light source. The wavelength conversion element wavelength-converts laser light of a first wavelength into laser light of a second wavelength of 400 nm or less. After the first section, which is a time section before a change point at which the specific output, which is the output that contributes to the wavelength conversion to the second wavelength laser light, of the output of the first wavelength laser light, the temperature control unit changes. is a time interval in which the specific output is a constant time interval, the laser control information of the second interval is acquired before the output change point of the second interval, and based on the acquired laser control information of the second interval to control the temperature of the wavelength conversion element in the second section.

In the laser device according to the present disclosure, when the output of laser light with a specific wavelength changes significantly in a short period of time, the output fluctuation, output decrease, etc. of the wavelength-converted laser light can be corrected without complicating the device configuration. There is an effect that it can be avoided.

1 is a diagram schematically showing an example of a configuration of a laser processing apparatus including a laser device according to Embodiment 1; FIG. FIG. 4 is a diagram showing an example of temperature adjustment processing in the temperature adjustment unit; FIG. 4 is a diagram showing an example of temperature control processing in the temperature control unit of the laser device according to Embodiment 1; FIG. 11 is a perspective view schematically showing an example of the structure of a wavelength conversion element and a temperature adjustment section in a laser device according to Embodiment 3; FIG. 5 is a diagram showing an example of changes in temperature measurement values when the active region of the wavelength conversion element in the laser device according to Embodiment 3 is position A in FIG. 4; FIG. 5 is a diagram showing an example of changes in temperature measurement values when the active region of the wavelength conversion element in the laser device according to Embodiment 3 is position B in FIG. 4; FIG. 11 is a diagram schematically showing an example of a configuration of a laser processing apparatus including a laser device according to Embodiment 3; FIG. 10 is a diagram showing an overview of a control method using temperature setting information in a laser device according to a third embodiment; A diagram schematically showing an example of a configuration of a laser device according to a seventh embodiment; A block diagram schematically showing an example of a hardware configuration of a laser control unit, a temperature control unit, and a processing control unit provided in the laser processing apparatuses according to Embodiments 1 to 9.

A laser device and a laser processing device according to embodiments of the present disclosure will be described in detail below with reference to the drawings. The embodiments described below are examples, and the scope of the present disclosure is not limited by the embodiments described below.

Further, in the present disclosure, an upper limit value and a lower limit value are provided for the output value, and a state in which the output fluctuation value fluctuates between the upper limit value and the lower limit value described on the left may be called constant. Also, the upper limit and lower limit may be set such that the change in output when changing from the first section to the second section is greater than the difference between the upper limit and the lower limit.

Embodiment 1.
FIG. 1 is a diagram schematically showing an example of a configuration of a laser processing apparatus including a laser device according to Embodiment 1. FIG. The laser processing device 1 includes a laser device 10 , a stage 21 , a laser scanning section 22 and a processing control section 23 .

The laser device 10 is a device that emits a laser beam L2 of a second wavelength. The laser device 10 includes a laser light source 11 , a laser control section 12 , a wavelength conversion element 13 , a temperature adjustment section 14 , a temperature sensor 15 and a temperature control section 16 .

The laser light source 11 oscillates laser light L1 of a first wavelength, which is a specific wavelength. In one example, the first wavelength laser light L1 is visible light with a wavelength of 532 nm. An example of the laser light source 11 is a laser oscillator.

The laser control unit 12 controls the laser light source 11 based on laser control information, which is information regarding control of the laser light source 11 . Here, the on-time, which is a time interval before the change time point at which the specific output, which is the output contributing to the wavelength conversion to the second-wavelength laser light L2, of the output of the first-wavelength laser light L1, and the on-time A case where the laser light L1 of the first wavelength is input to the wavelength conversion element 13 so as to include an off time in which the specific output is a constant time interval after the time is taken as an example. . That is, the on-time is a period during which the wavelength conversion element 13 converts the laser light L1 of the first wavelength into the laser light L2 of the second wavelength, and the off-time is the conversion to the laser light L2 of the second wavelength. is a rest period during which no The on-time corresponds to the first interval and the off-time corresponds to the second interval. An example of the laser control information is the average output of the laser light L1 of the first wavelength, the drive current of the laser device 10, and the repetition frequency of the laser light L1 of the first wavelength, which are related to the OFF time of the laser light L2 of the second wavelength. It is a characteristic of laser light including at least one of them.

In one example, the ON time and OFF time change at least one of the average power of the laser light L1 of the first wavelength, the driving current of the laser device 10, and the repetition frequency of the laser light L1 of the first wavelength. can be switched by The ON time is the time during which wavelength conversion is performed by inputting the laser light L1 of the first wavelength into the wavelength conversion element 13 with a predetermined peak power or higher. In one example, the laser control unit 12 switches from on-time to off-time by switching to continuous oscillation at a constant output and making the peak power less than a constant value.

The wavelength conversion element 13 converts all or part of the first wavelength laser light L1 emitted from the laser light source 11 into laser light L2 of a second wavelength shorter than the first wavelength by a nonlinear effect. In one example, the wavelength conversion element 13 converts the ultraviolet laser light L2 having a wavelength of 400 nm or less. The wavelength conversion element 13 is, for example, a CsLiB ₆ O ₁₀ (CLBO) crystal. When the wavelength conversion element 13 is a CLBO crystal, all or part of the visible laser light L1 with a wavelength of 532 nm is wavelength-converted by the wavelength conversion element 13 into laser light L2 with a wavelength of 266 nm. The wavelength conversion element 13 emits the converted laser light L<b>2 of the second wavelength to the laser scanning unit 22 . That is, the laser device 10 oscillates the laser light L2 of the second wavelength.

The temperature adjuster 14 adjusts the temperature so that the active region, which is the region of the wavelength conversion element 13 through which the laser light L1 of the first wavelength passes, is maintained at a predetermined target temperature. The target temperature is a temperature at which the heated active region is wavelength-converted with a wavelength conversion efficiency equal to or higher than a predetermined reference value. The temperature adjustment unit 14 is, for example, a Peltier element that is a thermoelectric element that supplies and absorbs heat. That is, the temperature adjustment unit 14 adjusts the temperature by performing at least one of heat input and exhaust heat to the wavelength conversion element 13 so that the temperature of the wavelength conversion element 13 approaches the target temperature.

The temperature sensor 15 detects the temperature of the wavelength conversion element 13. The temperature sensor 15 outputs the detected temperature of the wavelength conversion element 13 to the temperature controller 16 .

The temperature control unit 16 adjusts the target temperature of the temperature adjustment unit 14 while measuring the temperature of the wavelength conversion element 13 with the temperature sensor 15 so that the temperature of the working region of the wavelength conversion element 13 is maintained within a predetermined temperature range. to control. Further, in Embodiment 1, the temperature control unit 16 is connected to the laser control unit 12, and the laser control unit 12 outputs the laser light L1 having the first wavelength from the laser control unit 12 during the ON time for the OFF time after the current time. Get information. The temperature control unit 16 calculates a target temperature so that the temperature of the active region of the wavelength conversion element 13 during the OFF time does not deviate from a predetermined temperature range, and sets the calculated target temperature in the temperature adjustment unit 14 . Calculation of the target temperature by the temperature control unit 16 will be described later.

The stage 21 holds a processing target 50 that is a laser processing target. In one example, the stage 21 can move in a direction parallel to the holding surface that holds the workpiece 50, a direction perpendicular to the holding surface, around an axis perpendicular to the holding surface, and in a plane parallel to the holding surface. It has a configuration movable about one axis. That is, the stage 21 moves in a direction parallel to the holding surface, a direction perpendicular to the holding surface, around an axis perpendicular to the holding surface, and around one axis in a plane parallel to the holding surface. A drive system (not shown) is provided to enable this.

The laser scanning unit 22 scans the second wavelength laser light L2 emitted from the laser device 10 . An example of the laser scanning unit 22 is a processing head. In one example, the laser scanning unit 22 may have a configuration capable of moving in a direction parallel to the holding surface of the stage 21 and a direction perpendicular to the holding surface. That is, the laser scanning unit 22 may be provided with a driving system (not shown) that enables the laser scanning unit 22 to move in the direction parallel to and perpendicular to the holding surface.

The processing control unit 23 controls the operations of the laser scanning unit 22 and the stage 21 .

In the laser processing apparatus 1 of Embodiment 1, the laser device 10, the stage 21, the laser scanning section 22 and the processing control section 23 are illustrated, but the stage 21, the laser scanning section 22 and the processing control section 23 need to be accompanied. You can omit them instead.

The laser control unit 12, the temperature control unit 16, and the processing control unit 23 are connected so as to be able to exchange information with each other. Thereby, the laser control unit 12, the temperature control unit 16, and the processing control unit 23 can recognize the oscillation state and the output control state of the laser.

Next, temperature adjustment processing in the temperature adjustment unit 14 will be described. FIG. 2 is a diagram illustrating an example of temperature adjustment processing in the temperature adjustment unit. FIG. 2 shows a graph 200 showing an example of measured values of the temperature of the working area, which is the area through which the laser beam L1 of the first wavelength passes, in the wavelength conversion element 13, and changes in the output of the laser beam L2 of the second wavelength. are shown in association with a graph 210 showing an example of . In the graph 200 , the horizontal axis is time, and the vertical axis is the measured value of the temperature in the active region of the wavelength conversion element 13 . In the graph 210, the horizontal axis is time, and the vertical axis is the power of the second wavelength laser light L2. In FIG. 2, the temperature control unit 16 performs temperature control so that the temperature of the wavelength conversion element 13 approaches the set temperature _TC . As shown in FIG. 2, the set temperature _TC is a constant value _TC0 .

When the laser beam L1 of the first wavelength is incident on the wavelength conversion element 13, the wavelength is converted in the active region in the wavelength conversion element 13, and at the same time, the wavelength-converted laser beam L2 of the second wavelength passes through. Fever develops. This heat generation heats the working area. The wavelength conversion element 13 is provided with a temperature adjustment section 14, and the temperature adjustment section 14 maintains a temperature at which the heated action region is wavelength-converted with a wavelength conversion efficiency equal to or higher than a predetermined reference value. Adjust the temperature so that For example, if T _C0 is the set temperature T _C of the temperature adjustment unit 14 and T _d is the amount of temperature rise in the action region due to the heat generated by the laser beam L2 of the second wavelength, the temperature of the action region is T _C0 +T _d . . Due to the heat capacity of the wavelength conversion element 13, the temperature adjustment section 14, etc., it takes time for the temperature of the action region to follow the set temperature, so the set temperature of the temperature adjustment section 14 and the temperature of the action region do not necessarily match. .

The temperature of the wavelength conversion element 13 is maintained at a temperature at which the output of the laser light L1 of the first wavelength is equal to or higher than a predetermined value, and the wavelength is converted with a wavelength conversion efficiency equal to or higher than the predetermined reference value at this time. It shall be At this time, the temperature of the wavelength conversion element 13 with respect to the set temperature T _C0 of the temperature adjustment unit 14 receives a temperature rise value T _d due to heat generation from the laser beam L2 of the second wavelength, and becomes T _C0 +T _d . . The temperature T _C0 +T _d at this time is the temperature at which the wavelength is converted with a wavelength conversion efficiency equal to or higher than a predetermined reference value.

Here, as shown in FIG. 2, the on-time Δt _on is the time during which part of the laser light L1 of the first wavelength is wavelength-converted by the input of the laser light L1 of the first wavelength, and the wavelength is completely converted. It is assumed that an off time Δt _off which is a time when the power supply is off is set. That is, the on-time Δt _on is a time interval in which the specific output, which is the output that contributes to the wavelength conversion of the laser light L1 having the first wavelength to the laser light L2 having the second wavelength, is input, and the specific output is the wavelength It is assumed that off-time Δt _off , which is a constant time interval that does not contribute to conversion, is set.

When the on-time Δt _on changes to the off-time Δt _off at time t ₂₁ , the heat generated by the laser light L2 of the second wavelength to the wavelength conversion element 13 is reduced or eliminated. As a result, the temperature of the wavelength conversion element 13 gradually decreases, and at time t ₂₃ after a certain period of time, the temperature of the wavelength conversion element 13 coincides with T _C0 . Then, at the start time _t22 of the ON time Δt _on at which the first wavelength laser beam L1 is input again, the temperature of the active region changes from T _C0 to T _C0 +T _d again. T _C0 +T _d is the temperature at which the wavelength is converted with a wavelength conversion efficiency equal to or higher than a predetermined reference value. The wavelength conversion efficiency from time t ₂₂ immediately after incidence of the first wavelength laser beam L1 to time t ₂₄ when the temperature of the active region changes to the temperature T _C0 +T _d or a predetermined temperature range is determined in advance. below the reference value. The time from time _t22 to time _t24 is the time _Δt25 required for the output of the second wavelength laser light L2 to rise. In the following, the time required for rise is also referred to as rise time. The rise time Δt ₂₅ is lengthened because the temperature of the active region must be increased by T _d .

In machining such as trepanning, in which a hole is drilled while leaving the core material, the number of pulses applied to the same place is small, and if it takes time for the output to rise, machining defects are likely to occur. This is because only a pulsed laser with a low output at the time of rising is used for processing. In order to avoid this, it is conceivable to not perform processing with a laser output corresponding to the rising time _Δt25 , or to change the processing conditions only at the rising time _Δt25 . However, in this case, the time during which no processing is performed is extended, or the time during which processing is performed is extended, and the efficiency of the laser processing is lowered. Therefore, in Embodiment 1, the temperature control unit 16 shortens the rise time of the output of the second wavelength laser light L2 emitted from the wavelength conversion element 13 when switching from the OFF time Δt _off to the ON time Δt _on . temperature control.

FIG. 3 is a diagram showing an example of temperature control processing in the temperature control unit of the laser device according to Embodiment 1. FIG. FIG. 3 shows a graph 300 showing an example of measured values of the temperature of the working area, which is the area through which the laser beam L1 of the first wavelength passes, in the wavelength conversion element 13, and the output change of the laser beam L2 of the second wavelength. are shown in association with a graph 310 showing an example. In the graph 300 , the horizontal axis is time, and the vertical axis is the measured value of the temperature of the active region of the wavelength conversion element 13 . In the graph 310, the horizontal axis is time, and the vertical axis is the power of the second wavelength laser light L2. In FIG. 3, it is assumed that the temperature control unit 16 performs temperature control so as to keep the temperature of the wavelength conversion element 13 at the set temperature _TC . As shown in FIG. 3, the set temperature T _C is indicated by a dotted line, and unlike the case of FIG. 2, it is not always constant.

The temperature control unit 16 sets the start time t _{31 and the end time t 32 of the off time Δt off from the laser control unit 12 before the start time t 31} _and _the _end time t ₃₂ of the off time Δt _off . It is obtained before the change time point at which the specific output of the laser light L1 of the wavelength changes. In other words, the temperature controller 16 anticipates the OFF time Δt _off . Then, the temperature control unit 16 calculates the corrected temperature T _F according to the off-time Δt _off read ahead. The correction temperature T _F is the set temperature T _C of the action region during the off time Δt _off during which wavelength conversion is not performed, and the wavelength conversion efficiency equal to or higher than a predetermined reference value when the laser beam L1 of the first wavelength is incident. is the temperature to be corrected so as to be equal to or higher than the temperature at which

For example, when the set temperature T _C is T _C0 +T _F , which is the sum of the set temperature T _C0 and the correction temperature T _F during the ON time Δt _on , the temperature control unit 16 allows the laser beam L1 of the first wavelength to enter. The correction temperature _TF can be calculated so that the wavelength conversion efficiency of the active region at the time of the above becomes equal to or higher than a predetermined reference value. Note that the correction temperature T _F may be changed with time. In one example, as shown in FIG. 3, when the temperature of the action region drops due to the lapse of a certain rest time Δt _r during the OFF time Δt _off , the temperature control unit 16 changes the temperature adjustment unit 14 to A new set temperature T _C of the temperature adjuster 14 is T _C0 +T _F obtained by adding the correction temperature T _F to the set temperature T _C0 .

At this time, the set temperature T _C0 +T _F of the temperature adjustment unit 14 is the temperature at which the wavelength is converted with a wavelength conversion efficiency equal to or higher than a predetermined reference value at the moment when the laser light L1 of the first wavelength is input to the action region. . Also, the set temperature T _C0 +T _F for the off time Δt _off corresponds to the second section set temperature. After that, at time t ₃₂ , the ON time Δt _on occurs, and the laser light L 1 of the first wavelength is input to the wavelength conversion element 13 again. In this case, immediately after the laser light L1 of the first wavelength is input, the temperature of the active region is the temperature at which the wavelength is converted with the wavelength conversion efficiency equal to or higher than the predetermined reference value, so the rise time Δt ₃₅ is as shown in FIG. is shortened compared to the rise time Δt ₂₅ for . That is, the output of the second wavelength laser light L2 rises in a shorter time than in the case of FIG. This temperature control makes it possible to efficiently oscillate the laser beam L2 of the second wavelength at a high output.

When the ultraviolet laser light L2 with a wavelength of 400 nm or less passes through the wavelength conversion element 13, the absorption is greater than that of the laser light L2 with a wavelength over 400 nm such as infrared light or visible light. Therefore, the temperature adjustment unit 14 in the laser device 10 of Embodiment 1 can shorten the rise time as compared with the case of generating the laser light L2 having a wavelength exceeding 400 nm.

As described above, the temperature control unit 16 acquires the laser control information of the laser light source 11 for the off time Δt _off before the times t ₃₁ and t ₃₂ at which the output changes during the off time Δt _off . Based on the laser control information for Δt _off , the temperature of the wavelength conversion element 13 during the off time Δt _off is controlled. At this time, the temperature control unit 16 uses the laser control information to calculate the change in the temperature of the active region during the off time Δt _off . Then, the temperature control unit 16 adjusts the ON time so that the temperature of the active region at the moment when the laser light L1 of the first wavelength is input becomes a temperature at which the wavelength is converted with a wavelength conversion efficiency equal to or higher than a predetermined reference value. A correction temperature T _F for correcting the set temperature T _C0 at Δt _on is calculated, and the temperature of the wavelength conversion element 13 is controlled using T _C0 +T _F .

The laser control information may be any information that can calculate the change in temperature of the wavelength conversion element 13 at the time of switching from the OFF time Δt _off to the ON time Δt _on . In other words, the laser control information may be any information that has a correlation with the heat generated by the laser beam L2 of the second wavelength. In one example, the laser control information can be an amount that correlates with the amount of heat generated per unit time in the wavelength conversion element 13 . This makes it possible to calculate the correction temperature T _F at the off time Δt _off using the laser control information. By using such laser control information, the temperature control unit 16 adjusts the temperature of the wavelength conversion element 13 during the off time Δt _off based on a comparison between the amount of heat generated during the on time Δt _on and the amount of heat generated during the off time Δt _off . can be controlled. Specifically, the temperature control unit 16 acquires the element temperature, which is the temperature of the wavelength conversion element 13 measured by the temperature sensor 15, and heats the wavelength conversion element 13 so that the element temperature approaches the target temperature. Temperature control is performed by implementing heat and/or heat. Thus, the wavelength conversion element 13 can be controlled because the laser control information has a correlation with the heat generation of the laser beam L2 of the second wavelength.

Further, before the start of the off-time Δt _off , the temperature control unit 16 determines the amount of heat generated by the wavelength conversion element 13 during the off-time Δt _off based on the amount of heat generated by the wavelength conversion element 13 during the off-time Δt _off . Then, the temperature of the wavelength conversion element 13 is controlled for the on-time Δt _on so that the temperature of the wavelength conversion element 13 approaches the set temperature _TC at the end of the on _- time Δt _on . to run. Since the laser control information has a correlation with the heat generation of the wavelength conversion element 13 by the laser light L2 of the second wavelength, the temperature control unit 16 controls the change in the heat generation of the wavelength conversion element 13 by the laser light L2 of the second wavelength according to the laser control information. can be read ahead. As a result, the temperature of the wavelength conversion element 13 can be controlled within a predetermined temperature range.

In the first embodiment, the laser device 10 includes a laser light source 11 that emits a laser beam L1 of a first wavelength, and a laser light source 11 according to laser control information for controlling the emission of the laser beam L1 of the first wavelength from the laser light source 11. 11, a wavelength conversion element 13 for wavelength-converting laser light L1 of a first wavelength from the laser light source 11 into laser light L2 of a second wavelength shorter than the first wavelength, and a wavelength conversion element. and a temperature controller 16 that controls the temperature maintained by the wavelength conversion element 13 by the temperature controller 14 . The temperature control unit 16 acquires the laser control information for the off time Δt _off before the output change point of transition to the off time Δt _off , and performs wavelength conversion for the off time Δt _off based on the laser control information for the off time Δt _off . Control the temperature of the element 13 . Specifically, at the sum T _C0 +T _F of the set temperature T _C0 and the correction temperature T _F in the ON time Δt _on , the wavelength conversion efficiency of the action region when the laser beam L1 of the first wavelength is incident is determined in advance. The correction temperature T _F of the temperature adjustment unit 14 during the OFF time Δt _off is calculated and set in the temperature adjustment unit 14 so as to be equal to or higher than a predetermined value. The temperature adjustment unit 14 adjusts the temperature during the OFF time Δt _off to a temperature obtained by adding the correction temperature T _F to the set temperature T _C0 . This has the effect of shortening the rise time of the laser beam L2 of the second wavelength when the off-time Δt _off transitions to the on-time Δt _on compared to the conventional art. In other words, the temperature control timing can be pre-read and executed by pre-reading the laser output change based on the laser control information from the laser control unit 12 side, and the temperature of the wavelength conversion element 13 can be brought closer to the target temperature. be able to. As a result, when the output of the laser light L1 of the specific wavelength changes greatly in a short time, it is possible to avoid output fluctuations, output reduction, etc. of the wavelength-converted laser light L2 without complicating the device configuration. It is possible to obtain a laser device 10 capable of

Embodiment 2.
In FIG. 3 of Embodiment 1, when the laser light L2 of the second wavelength is emitted at the start time _t32 of the ON time Δt _on with an output power equal to or greater than a predetermined value, the wavelength conversion element 13 receives the second wavelength The temperature of the active area rises due to the heat generated by the laser beam L2, and the temperature moves away from the predetermined temperature range. In one example, it becomes higher than the predetermined temperature T _C0 +T _d . Therefore, the temperature control unit 16 sets a constant time from the rise of the laser beam L2 of the second wavelength so that the temperature of the active region does not deviate from the predetermined temperature range after the start time _t32 of the ON time Δt _on . The correction temperature _TF may be gradually set to 0 over time. An example of a constant time can be the rise time Δt ₃₅ .

In the second embodiment, at the start time t ₃₂ of the on-time Δt _on , the temperature control unit 16 gradually reduces the correction temperature T _F to 0 over a certain period of time from the rise of the second-wavelength laser beam L 2 . did. By this temperature control, the temperature control unit 16 can prevent the temperature of the active region from deviating from the predetermined temperature range with respect to the temperature at which the wavelength is converted with the wavelength conversion efficiency equal to or higher than the predetermined reference value. . As a result, there is an effect that the output of the laser light L2 of the second wavelength can be stably and efficiently oscillated.

Embodiment 3.
FIG. 4 is a perspective view schematically showing an example of the structure of the wavelength conversion element and the temperature adjustment section in the laser device according to Embodiment 3. FIG. In the example shown in FIG. 4, the wavelength conversion element 13 is arranged above the temperature adjustment section 14 with a heat diffusion plate 31 interposed therebetween. The thermal diffusion plate 31 is a member that makes the temperature distribution in the wavelength conversion element 13 uniform. The area of the incident surface 13a of the wavelength conversion element 13, which is the surface on which the laser beam L1 of the first wavelength is incident, is sufficiently larger than the areas of the

active regions

131a and 131b through which the laser beam L1 of the first wavelength passes. . Therefore, the positions of the

active regions

131 a and 131 b can be set at arbitrary positions within the incident surface 13 a of the wavelength conversion element 13 . Positions A and B of

action regions

131 a and 131 b may be relatively close to temperature adjustment section 14 or may be relatively far from temperature adjustment section 14 . FIG. 4 illustrates an action area 131a provided at a position A far from the temperature adjustment section 14 and an action area 131b provided at a position B close to the temperature adjustment section 14. As shown in FIG. In the following description, the

action regions

131a and 131b are simply referred to as the action region 131 when there is no need to distinguish them individually.

FIG. 5 is a diagram showing an example of changes in temperature measurement values when the active region of the wavelength conversion element in the laser device according to Embodiment 3 is position A in FIG. FIG. 6 is a diagram showing an example of changes in temperature measurement values when the active region of the wavelength conversion element in the laser device according to Embodiment 3 is position B in FIG. In FIGS. 5 and 6, the horizontal axis is time, and the vertical axis is the measured value of the temperature in the working region of the wavelength conversion element 13. In FIG.

The second wavelength laser light L<b>2 passing through the wavelength conversion element 13 has a different distance from the temperature adjustment section 14 depending on the positions A and B of the wavelength conversion element 13 . Even if heat is similarly generated by the laser beam L2 of the second wavelength, if the distance from the temperature adjustment unit 14 is different, the temperature adjustment of the

action regions

131a and 131b by the temperature adjustment unit 14 is performed as shown in FIGS. There may be a difference in the rising temperature _Td , which is the rising temperature due to different effects. In addition, the temperature rise _Td may differ depending on the frequency and predetermined output value of the passing laser light L2 of the second wavelength. Furthermore, even when the physical properties of the wavelength conversion element 13 are different, the amount of heat generated by the laser light L2 of the second wavelength with respect to the wavelength conversion element 13 may also differ, which may also cause a difference in the temperature rise _Td . be. As described above, when the set temperature T _C and the rising temperature T _d are different, the corrected temperature T _F described in the first embodiment is also different in each case.

Therefore, the temperature control unit 16 performs appropriate settings determined by the positions A and B of the

active regions

131a and 131b, the frequency and predetermined output value of the laser light L2 of the second wavelength, the physical property values of the wavelength conversion element 13, and the like. It may have temperature setting information in which the temperature T _C and the correction temperature T _F are tabulated. In this case, the temperature control section 16 has a storage section (not shown) that stores the temperature setting information.

FIG. 7 is a diagram schematically showing an example of the configuration of a laser processing apparatus equipped with a laser device according to Embodiment 3. FIG. In addition, the same code|symbol is attached|subjected to the component same as FIG. 1, and the description is abbreviate|omitted. In FIG. 7 , the laser device 10 further includes an incident position changing section 32 . The incident position changing unit 32 changes the incident position of the laser light L<b>1 of the first wavelength emitted from the laser light source 11 to the wavelength conversion element 13 . The incident position changing unit 32 is capable of changing the relative positions of the emission end of the laser light L1 of the first wavelength in the laser light source 11 and the incident surface of the wavelength conversion element 13 on which the laser light L1 of the first wavelength is incident. If it is In one example, the incident position changing section 32 is a drive system provided in at least one of the laser light source 11 and the wavelength conversion element 13 . The incident position changer 32 is controlled by the laser controller 12 in one example. The laser control unit 12 controls at least the laser light source 11 and the wavelength conversion element 13 so that the output end of the laser light source 11 is positioned at a desired position on a coordinate system based on a predetermined position on the incident surface. Control to change one position.

The temperature control unit 16 obtains in advance from the laser control unit 12 the incident position of the laser beam L1 of the first wavelength to the wavelength conversion element 13 during the ON time Δt _on , and adjusts the wavelength conversion element 13 based on the obtained incident position. to control the temperature of FIG. 8 is a diagram showing an outline of a control method using temperature setting information in the laser device according to the third embodiment. The temperature setting information 161 corresponds the set temperature T _C and the correction temperature T _F to the material characteristic information of the wavelength conversion element 13, which is parameters such as the position of the active region 131 and the frequency and output of the second wavelength laser light L2. This is the information attached. In FIG. 8, a data table in which the set temperature T _C and the correction temperature T _F are associated with each position through which the laser beam L2 of the second wavelength passes, that is, each position of the action region 131 is shown for each physical property value of the wavelength conversion element 13. It shows the case where it is provided in

During actual operation, the temperature control unit 16 controls the combination of the conditions in the temperature setting information 161, that is, the position of the active region 131, the frequency and output of the laser beam L2 of the second wavelength, and the physical property values of the wavelength conversion element 13. from the temperature _setting information ₁₆₁ . The temperature control unit 16 sets the read setting temperature T _C and correction temperature T _F in the temperature adjustment unit 14 . By doing so, even if the parameters of the laser beam L2 of the second wavelength and the position of the active region 131 are changed, or if the physical property value is changed due to the replacement of the wavelength conversion element 13, the first embodiment can be used. Control by the temperature adjustment unit 14 described above can be performed. That is, the temperature control unit 16 controls the set temperature T _C corrected by the correction temperature T _F such that the temperature of the action region 131 is always a temperature at which wavelength conversion is performed with a wavelength conversion efficiency equal to or higher than a predetermined reference value. can do. As a result, the output of the laser light L2 of the second wavelength can be stably and efficiently oscillated.

The temperature setting information 161 actually operates in a plurality of combinations in which the position, frequency, and output of the action area 131 are changed, and sets the temperature T so that the temperature of the action area 131 operates within a predetermined temperature range. It is created by exhaustively ascertaining the values of _C and correction temperature T _F . Based on this result, the combination of the position of the active region 131, the frequency and output of the second wavelength laser light L2, and the physical property value of the wavelength conversion element 13 is associated with the set temperature T _C and the correction temperature T _F. The temperature setting information 161 is created and stored in the temperature control unit 16 .

In the third embodiment, the set temperature T _C and the correction temperature T _F corresponding to the parameters such as the position of the active region 131 and the frequency and output of the second-wavelength laser beam L2 are read from the temperature setting information 161, and the read set temperature T _C and the correction temperature T _F are set in the temperature adjuster 14 . Even when the operating conditions change such that the incident position of the laser beam L1 of the first wavelength to the wavelength conversion element 13 is changed, the values of the set temperature _TC and the correction temperature _TF corresponding to this change are stored in the temperature setting information. 161, and the temperature control unit 16 controls the temperature of the wavelength conversion element 13 based on the values of the set temperature T _C and the correction temperature T _F that have been obtained. As a result, the position of the active region 131 of the wavelength conversion element 13 is not fixed because the position of the active region 131 can be changed in a predetermined period. As a result, deterioration due to irradiation of the laser light L1 of the first wavelength and passage of the laser light L2 of the second wavelength to a specific portion of the wavelength conversion element 13 can be suppressed, and the wavelength conversion element 13 has a long life. has the effect of

Further, the temperature control unit 16 changes not only the incident position to the wavelength conversion element 13 but also the frequency of the laser light L2 of the second wavelength, the predetermined output value, and the physical property value of the wavelength conversion element 13. Also for such a change in usage conditions, the values of the set temperature T _C and the correction temperature T _F corresponding to this change are obtained from the temperature setting information 161 . Then, the temperature control unit 16 controls the temperature of the wavelength conversion element 13 based on the acquired set temperature T _C and correction temperature T _F without calculating the correction temperature T _F. It can be performed. In addition, since the control temperature can be obtained from the information stored in the storage section of the temperature control section 16 without performing pre-measurement for temperature control each time, the laser device 10 can be operated efficiently. Also, by converting the temperature setting information 161 into a data table, information for temperature control can be calculated from the data table.

Embodiment 4.
In temperature control using the temperature setting information 161 created in Embodiment 3, when referring to the correction temperature _TF from the temperature setting information 161, the position of the active region 131 or the physical property value of the wavelength conversion element 13 is the temperature setting information. 161 may not. In the laser device 10 according to the fourth embodiment, in such a case, the temperature control unit 16 determines a value not included in the temperature setting information 161 based on the position of the active region 131 of the temperature setting information 161 or the physical property value of the wavelength conversion element 13. may be obtained using an interpolation method such as linear interpolation. Thereby, the correction temperature T _F can be determined using the position of the active region 131 or the physical property value of the wavelength conversion element 13 that is not included in the temperature setting information 161 .

In Embodiment 4, the temperature control unit 16 determines the correction temperature T _F that does not exist in the temperature setting information 161 by interpolation using data in the temperature setting information 161 . As a result, it becomes possible to use the wavelength conversion element 13 having the active region 131 or the physical property value not included in the temperature setting information 161 . As a result, even in situations where the temperature setting information 161 cannot be directly referred to, including when the wavelength conversion element 13 is moved or when the wavelength conversion element 13 is replaced, the output of the second wavelength equal to or greater than the predetermined value is detected. There is an effect that it becomes possible to realize the emission of the laser light L2.

Embodiment 5.
Immediately after switching from the on-time Δt _on to the off-time Δt _off , the temperature of the wavelength conversion element 13 approaches the set temperature T _C by the temperature adjuster 14 as the off-time Δt _off elapses. In order to bring the temperature of the active region 131 of the wavelength conversion element 13 to the temperature to which the correction temperature T _F is added, the longer the OFF time Δt _off is, the more heat is generated by the temperature adjustment section 14 . When the _off -time Δt _off becomes longer so that the temperature of the action area 131 becomes equal to the set temperature T _C , the amount of heat generated by the temperature adjustment unit 14 for applying the correction temperature T _F becomes maximum. The amount of heat generated by the temperature control unit 14 is constant.

The correction temperature T _{F and the amount of heat generation required to give the correction temperature T F} _for the length of the off time Δt _off are made into a data table in advance, and the heat generation amount is determined according to the length of the off time Δt _off . good too. This allows the temperature adjuster 14 to add the correction temperature T _F by referring to the data table from the temperature controller 16 before the temperature of the action region 131 becomes constant at the set temperature T _C . In addition, this makes it possible to eliminate the need for temperature measurement by the temperature sensor 15 and temperature control using the temperature measurement results. This makes it possible to apply the correction temperature T _F to the wavelength conversion element 13 in a shorter time than in temperature control that requires feedback via temperature measurement.

These effects prevent the off-time Δt _off from changing in time, including when the on-time Δt _on is again short before the temperature of the active region 131 reaches the set temperature T _C after the off-time Δt _off . Even in some cases, the correction temperature T _F can be applied to the wavelength conversion element 13 . The length of the off time Δt _off can be recognized by the temperature control section 16 cooperating with the laser control section 12 and reading the laser control information in advance. As a result, the output of the laser light L2 of the second wavelength can be stably and efficiently oscillated.

Embodiment 6.
In Embodiments 1 to 5, wavelength conversion is performed by inputting the laser light L1 of the first wavelength into the wavelength conversion element 13 with a predetermined peak power or higher during the ON time Δt _on . Further, in switching from the on-time Δt _on to the off-time Δt _off , the laser control unit 12 switches to continuous oscillation at a constant output so that the peak power becomes less than a constant. However, switching to the off time Δt _off is not limited to this method.

In addition, switching to the off time Δt _off can also be performed by increasing the frequency of the pulse-oscillated laser light L1 of the first wavelength at a constant output. In this case, the energy per pulse becomes small and the peak power is lowered, so wavelength conversion is not performed. The laser control information defines that the laser light L1 of the first wavelength is increased by the frequency at a constant output. Even when the operation is switched between the ON time Δt _on and the OFF time Δt _off , the heat generation in the wavelength conversion element 13 due to the laser light L2 of the second wavelength is reduced during the OFF time Δt _off . Temperature control is effective, and the output of the laser light L2 of the second wavelength can be stably and efficiently oscillated.

Embodiment 7.
In the sixth embodiment, the mechanism for switching to the OFF time Δt _off switches the laser light L1 of the first wavelength from pulse oscillation to continuous oscillation to attenuate the laser light L1 of the first wavelength. However, the mechanism for switching from the ON time Δt _on to the OFF time Δt _off is not limited to this.

FIG. 9 is a diagram schematically showing an example of the configuration of a laser device according to Embodiment 7. FIG. In addition, the same code|symbol is attached|subjected to the component same as FIG. 1, and the description is abbreviate|omitted. In FIG. 9, the laser device 10 further includes a modulation element 33 between the laser light source 11 and the wavelength conversion element 13. In FIG. The modulation element 33 is a general term for elements that can stop, attenuate, or rotate the polarization of the laser light L1 of the first wavelength that is incident on the wavelength conversion element 13 from the laser light source 11 .

In one example, the modulating element 33 may be a mechanical shutter arranged between the laser light source 11 and the wavelength converting element 13 . In this case, the mechanical shutter can block the laser beam L1 of the first wavelength and prevent it from passing through the wavelength conversion element 13 . Alternatively, the modulating element 33 may be an acousto-optic or electro-optic element. In this case, the polarization direction is controlled by the acousto-optic element or the electro-optic element so that wavelength conversion does not occur even when the laser light L1 of the first wavelength is transmitted through the wavelength conversion element 13 . In these cases, information about the modulation of the second-wavelength laser light L2 by the modulation element 33, that is, the off-time Δt _off of the second-wavelength laser light L2, is related to the mechanical shutter cut-off control, acousto-optical element, or electrical Control of the polarization direction by the optical element is defined by laser control information. Even when the operation is switched between the on-time Δt _on and the off-time Δt _off by these methods, the heat generation in the wavelength conversion element 13 due to the laser light L2 of the second wavelength is reduced during the off-time Δt _off . Therefore, the temperature control performed in Embodiments 1 to 5 is effective, and the output of the laser light L2 of the second wavelength can be stably and efficiently oscillated.

In addition to the case of using either the attenuation of the laser light L1 of the first wavelength in the sixth embodiment or the blocking of the laser light L1 of the first wavelength and the rotation of the polarized light in the seventh embodiment, Two or more of blocking, attenuation, and rotation of polarization of the laser light L1 of one wavelength may be combined. In other words, at least one of blocking, attenuation, and polarization rotation of the laser beam L1 of the first wavelength may be included.

Embodiment 8.
In FIG. 1, the laser processing apparatus 1 controls the output of the laser beam L2 of the second wavelength by the processing control unit 23, and synchronously operates between the laser scanning unit 22 and the stage 21 on which the processing target 50 is placed. Desired processing is performed by controlling. The processing control unit 23 operates the laser scanning unit 22 and the stage 21 so as to discontinuously irradiate the processing object 50 with the laser light L2 of the second wavelength in processing such as drilling or cutting and thermal processing such as quenching. You may let At this time, the processing control unit 23 may realize discontinuous irradiation of the processing object 50 by performing control to increase or decrease the output of the laser light L2 of the second wavelength according to the purpose of processing.

The correction temperature T _F added to the set temperature T _C0 of the temperature adjuster 14 may be increased or decreased in accordance with the time timing of the off time Δt _off of the laser light L1 of the first wavelength. Therefore, the temperature control unit 16 that controls the correction temperature T _F receives the switching timing between the ON time Δt _on and the OFF time Δt _off of the laser light L1 of the first wavelength from the laser control unit 12 or the processing control unit 23. may

Switching between continuous oscillation and pulse oscillation in Embodiments 1 to 5, or switching between on-time Δt _on and off-time Δt _off of wavelength conversion shown in Embodiments 6 and 7 is performed by moving or machining the object 50. The operation is interlocked with the scanning of the laser beam L2 of the second wavelength that matches the shape and the presence/absence of irradiation that matches the scanning. At this time, the temperature control unit 16 simultaneously performs the temperature control shown in Embodiments 1 to 5, so that the wavelength conversion efficiency is continuously equal to or higher than the predetermined reference value while the laser processing is being performed. The two-wavelength laser beam L2 can be stably emitted. As a result, highly efficient and stable laser processing can be realized.

Embodiment 9.
In the laser processing apparatus 1 of Embodiment 8, when the laser light source 11 oscillates or changes its output in synchronization with the laser processing control, the processing control unit 23 determines the timing of the ON time Δt _on or the OFF time Δt _off . , to the temperature controller 16 or the laser controller 12 . As a result, the temperature adjustment section 14 can operate according to the command from the processing control section 23 without performing temperature control via temperature measurement by the temperature sensor 15 . As a result, the temperature can be controlled with the minimum necessary information transmission, and high-speed and highly efficient laser processing can be realized. That is, by performing temperature control in conjunction with the processing control unit 23, it is possible to control the temperature based on information from the processing control unit 23, and the efficiency of the laser processing apparatus 1 can be improved.

The laser control unit 12, the temperature control unit 16, and the processing control unit 23 of the laser processing apparatus 1 according to Embodiments 1 to 9 are implemented by processing circuits. The processing circuit may be dedicated hardware, or may be a circuit with a processor. FIG. 10 is a block diagram schematically showing an example of a hardware configuration of a laser control section, a temperature control section, and a processing control section provided in the laser processing apparatuses according to Embodiments 1 to 9. FIG. The laser control unit 12 , the temperature control unit 16 and the processing control unit 23 each have a processor 501 and a memory 502 . Processor 501 and memory 502 are connected via bus line 503 . The laser control unit 12 , the temperature control unit 16 and the processing control unit 23 are implemented by the processor 501 executing programs stored in the memory 502 . Also, multiple processors and multiple memories may work together to achieve the above functions. Some of the functions of the laser control unit 12, the temperature control unit 16, and the processing control unit 23 are implemented as electronic circuits that are dedicated hardware, and other functions are realized using the processor 501 and the memory 502. You may do so. As an example, in the case of Embodiments 1 to 9, the laser control section 12 controls the operation of the laser light source 11 with an electrical signal, and the temperature control section 16 controls the operation of the temperature adjustment section 14 with an electrical signal. , the processing control unit 23 controls the operations of the stage 21 and the laser scanning unit 22 by electric signals.

The configurations shown in the above embodiments are only examples, and can be combined with other known techniques, or can be combined with other embodiments, without departing from the scope of the invention. It is also possible to omit or change part of the configuration.

1 laser processing device, 10 laser device, 11 laser light source, 12 laser control section, 13 wavelength conversion element, 13a incident surface, 14 temperature control section, 15 temperature sensor, 16 temperature control section, 21 stage, 22 laser scanning section, 23 Processing control unit, 31 heat diffusion plate, 32 incident position changing unit, 33 modulation element, 50 processing object, 131, 131a, 131b working area, 161 temperature setting information, L1 first wavelength laser light, L2 second wavelength laser light.

Claims

a laser light source that generates laser light of a first wavelength;
a laser control unit that controls the laser light source based on laser control information that is information about control of the laser light source;
a wavelength conversion element that wavelength-converts the laser light of the first wavelength to the laser light of the second wavelength of 400 nm or less;
In the time interval after the first interval, which is the time interval before the change point at which the specific output, which is the output that contributes to the wavelength conversion to the second wavelength laser light, among the outputs of the first wavelength laser light wherein the laser control information for a second section in which the specific output is a constant time section is acquired before the point of time when the output of the second section changes, and the laser control information for the acquired second section is obtained. a temperature control unit that controls the temperature of the wavelength conversion element in the second section based on
A laser device comprising:
The laser control information is an average output of the laser light of the first wavelength, a driving current of the laser device, and a repetition frequency of the laser light of the first wavelength, which are related to the pause time of the laser light of the second wavelength. Information indicating characteristics of laser light including at least one of
2. The laser device according to claim 1, wherein the temperature control unit uses the laser control information to read ahead the pause time of the laser light of the second wavelength.
Modulation of the laser light of the first wavelength is performed by performing at least one of stopping, attenuation, and rotation of polarization of the laser light of the first wavelength, which is related to the pause time of the laser light of the second wavelength. further comprising a modulating element for
The laser control information is information about modulation of the laser light of the second wavelength by the modulation element,
2. The laser device according to claim 1, wherein the temperature control unit uses the laser control information to read ahead the pause time of the laser light of the second wavelength.
The laser control information is an amount correlated with the amount of heat generated per unit time in the wavelength conversion element,
2. The temperature control unit controls the temperature of the wavelength conversion element in the second section based on a comparison between the amount of heat generated in the first section and the amount of heat generated in the second section. 4. The laser device according to any one of 3.
further comprising a temperature sensor for measuring an element temperature, which is the temperature of the wavelength conversion element;
The temperature control part
controlling the temperature of the wavelength conversion element by performing at least one of heat input and exhaust heat from the wavelength conversion element so that the temperature of the wavelength conversion element approaches a set temperature;
before the start of the second section, a second section set temperature, which is the set temperature of the wavelength conversion element in the second section, is calculated based on the amount of heat generated by the wavelength conversion element in the second section; ,
5. The temperature control of the wavelength conversion element is executed so that the temperature of the wavelength conversion element approaches the set temperature of the second section at the end of the first section. 1. The laser device according to 1.
further comprising an incident position changing unit that changes an incident position of the laser light of the first wavelength to the wavelength conversion element according to an instruction from the laser control unit;
6. The temperature control unit according to any one of claims 1 to 5, wherein the temperature control unit previously acquires the incident position in the first section, and controls the temperature of the wavelength conversion element based on the acquired incident position. 1. A laser device according to claim 1.
7. The laser device according to claim 6, wherein the temperature control unit controls the temperature of the wavelength conversion element based on temperature setting information indicating a relationship between each of the plurality of incident positions and the laser control information. .
8. The laser device according to claim 7, wherein the temperature setting information is a table showing the relationship between each of the plurality of incident positions and the laser control information.
a laser device according to any one of claims 1 to 8;
a laser beam scanning unit that irradiates a laser beam emitted from the laser device onto an object to be processed;
A laser processing device comprising: