JP6843219B1 - Light source for laser processing and laser processing equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source for laser processing and a laser processing apparatus capable of selectively emitting a plurality of types of pulsed light trains. A laser processing light source 2 includes a laser oscillation unit 21, a first light generation unit 22, a second light generation unit 23, and a control unit 24. The laser oscillator 21 emits the pulsed light train L1. The first light generation unit 22 generates a pulse light train L3 including a plurality of pulse light trains L2 by performing demultiplexing, propagation in a plurality of optical paths, and conjugation with respect to the pulse light train L1. .. The second light generation unit 23 generates a pulse light train L4 including at least one pulse light train L2 by selecting at least one pulse light train L2 from the plurality of pulse light trains L2 in the pulse light train L3. .. The control unit 24 controls the second light generation unit 23. The control unit 24 transmits a control signal C for selecting at least one pulse light train L2 from the plurality of pulse light trains L2 to the second light generation unit 23 in the pulse light train L3. [Selection diagram] Fig. 2

Description

The present invention relates to a light source for laser processing and a laser processing apparatus.

As a laser processing device that irradiates a work piece with a double-pulse light sequence consisting of a plurality of double-pulse lights, one pulse light sequence consisting of a plurality of single-pulse lights is demultiplexed into two pulse light sequences and demultiplexed 2. It is known that a double-pass optical sequence is generated by propagating each of the two pulsed optical paths in optical paths having different optical path lengths and combining the two pulsed optical paths (see, for example, Patent Document 1). ). The single-pulse light is one-pulse light composed of one pulse, and the double-pulse light is one-pulse light composed of two pulses that are close in time to, for example, several ps to 20 ns.

Japanese Unexamined Patent Publication No. 11-221684

However, in the laser processing apparatus as described above, the pulsed light trains irradiated to the workpiece may be limited to one type of pulsed light trains (for example, double pulsed light trains). In order to process the workpiece according to various uses, it is convenient if the workpiece can be selectively irradiated with a plurality of types of pulsed light trains.

Therefore, an object of the present invention is to provide a laser processing light source and a laser processing apparatus capable of selectively emitting a plurality of types of pulsed light trains.

The light source for laser processing of the present invention is capable of demultiplexing, propagating in a plurality of optical paths, and combining waves with respect to a laser oscillating unit that emits a first pulse light train and a first pulse light train. In the first light generator that generates a third pulse light train including a plurality of second pulse light trains and the third pulse light train, at least one second pulse light train is selected from the plurality of second pulse light trains. This includes a second light generation unit that generates a fourth pulse light train including at least one second pulse light train, and a control unit that controls the second light generation unit, and the control unit has a third pulse. In the light train, a control signal for selecting at least one second pulse light train from a plurality of second pulse light trains is transmitted to the second light generator.

In this light source for laser processing, a third pulse light train including a plurality of second pulse light trains is generated, and at least one second pulse light train is selected from the plurality of second pulse light trains in the third pulse light train. By doing so, a fourth pulse light train including at least one second pulse light train is generated. Therefore, according to this laser processing light source, it is possible to selectively emit a plurality of types of pulsed light trains.

In the light source for laser processing of the present invention, the laser oscillator unit transmits an electric signal having a frequency corresponding to the first pulse light train to the control unit, and the control unit may generate a control signal based on the electric signal. Good. According to this configuration, in the third pulse light train, the control of the second light generation unit that selects at least one second pulse light train from the plurality of second pulse light trains can be accurately and easily performed.

In the light source for laser processing of the present invention, the second light generating unit is a gain that constitutes an optical resonator together with a light cutting unit that generates a fourth pulse light train and a light cutting unit for the fourth pulse light train. It may be a reproduction amplifier having a medium and an excitation light source for irradiating the gain medium with excitation light. According to this configuration, the generation and amplification of the fourth pulse light train can be efficiently performed.

In the light source for laser processing of the present invention, each of the plurality of second pulse light trains may be a single pulse light train and a double pulse light train. According to this configuration, the third pulse light train includes, for example, a single pulse light train or a double pulse light train by selecting a single pulse light train or a double pulse light train from a plurality of second pulse light trains. A 4-pulse light train can be generated.

In the light source for laser processing of the present invention, the first light generation unit has different optical path lengths from the first demultiplexing unit that demultiplexes the first pulse light train into two pulse light trains, and the two pulsed lights. The first optical path has a first optical path and a second optical path that propagate each of the columns, and a first combine section that generates a third pulse optical array by merging the two pulse optical sequences. , The second demultiplexing part, which demultiplexes one of the two pulsed light trains demultiplexed by the first demultiplexing part into two subpulse light trains, and the second demultiplexing part, which have different optical path lengths and each of the two subpulse light trains. It has a third optical path and a fourth optical path for propagating the light, and a second combine section that combines two subpulse light trains, and the first combine section is demultiplexed by the first demultiplexing section. A third pulse light train may be generated by merging the other of the two pulse light trains and the pulse light train combined by the second light wave unit. According to this configuration, the generation of the third pulse light train can be easily performed.

In the light source for laser processing of the present invention, each of the first demultiplexing portion, the first demultiplexing portion, the second demultiplexing portion, and the second demultiplexing portion is a coupler, and the first light generating portion is on the optical path. It may further have an optical fiber connecting couplers adjacent to each other. According to this configuration, the generation of the third pulse light train can be performed more easily.

In the light source for laser processing of the present invention, the first light generation unit and the second light generation unit may be arranged through the space through which the third pulse light train propagates. According to this configuration, the first light generating unit can be easily attached and detached independently of the second light generating unit.

The laser machining apparatus of the present invention includes the above-mentioned laser machining light source, a support portion that supports the workpiece, and an irradiation portion that irradiates the workpiece with a pulsed light train emitted from the laser machining light source. ..

According to this laser processing apparatus, it is possible to selectively irradiate a work piece with a plurality of types of pulsed light trains. As a result, the workpiece can be appropriately processed according to various uses.

According to the present invention, it is possible to provide a laser processing light source and a laser processing apparatus capable of selectively emitting a plurality of types of pulsed light trains.

It is a block diagram of the laser processing apparatus of 1st Embodiment. It is a block diagram of the light source for laser processing shown in FIG. It is a block diagram of the 1st light generation part shown in FIG. It is a block diagram of the 1st light generation part of 2nd Embodiment. It is a block diagram of the 1st light generation part of the modification. It is a block diagram of the 1st light generation part of the modification.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each figure, the same or corresponding parts are designated by the same reference numerals, and duplicate description will be omitted.

[First Embodiment]
As shown in FIG. 1, the laser processing apparatus 1 includes a laser processing light source 2, an irradiation optical system (irradiation unit) 3, a support unit 4, and a processing position control unit 5. The laser processing apparatus 1 generates plasma on the surface of the work piece P such as metal by irradiating the surface of the work piece P such as metal with a pulsed light train which is pulse-oscillated laser light, and the work piece is generated by the shock wave generated by the plasma pressure. This is a device that plastically deforms the surface of P to a predetermined processing depth.

The laser processing light source 2 emits a pulsed light train. The irradiation optical system 3 irradiates the workpiece P with a pulsed light train emitted from the laser processing light source 2. The irradiation optical system 3 includes a shutter for switching between irradiation and non-irradiation of the pulsed light train, a lens for condensing the pulsed light train at the measurement position, a mirror, and the like.

The support portion 4 supports the workpiece P. The machining position control unit 5 controls the irradiation position of the pulsed light train with respect to the workpiece P. The processing position control unit 5 adjusts the irradiation position of the pulsed light train to the processing position of the workpiece P by moving at least one of the irradiation optical system 3 and the support unit 4.

As shown in FIG. 2, the laser processing light source 2 includes a laser oscillation unit 21, a first light generation unit 22, a second light generation unit 23, a control unit 24, and a user interface 25. ing. The laser oscillator 21 is, for example, a mode-locked fiber laser oscillator. The laser oscillator 21 outputs an electric signal E based on the pulsed light train (first pulsed light train) L1. The pulsed light train is a laser beam including a plurality of pulsed lights arranged at a predetermined time interval (pulse interval). The laser oscillator 21 transmits an electric signal E to the control unit 24. The electric signal E has a frequency corresponding to the pulsed light train L1. As an example, the frequency of the electric signal E is the same as the frequency of the pulsed light train L1.

The first light generation unit 22 includes a plurality of pulsed light trains (second pulsed light trains) L2 by performing demultiplexing, propagation in a plurality of optical paths, and conjugation with respect to the pulsed light train L1. A pulsed light train (third pulse light train) L3 is generated. In the present embodiment, the pulse light train L3 includes the pulse light train L21 and the pulse light train L22 as the pulse light train L2. That is, each of the plurality of pulsed light trains L2 is a pulsed light train L21 or a pulsed light train L22.

The second light generation unit 23 and the first light generation unit 22 are arranged through the space through which the pulsed light train L3 propagates. The second light generation unit 23 is a reproduction amplifier. Specifically, the second light generation unit 23 has a pair of mirrors 231,232, an optical cutout unit 233, a gain medium 234, and an excitation light source 235. The optical cutout portion 233 and the gain medium 234 are sandwiched by a pair of mirrors 231 and 232 in a state of being arranged side by side, and form an optical resonator with respect to a pulsed optical train.

The light cutting unit 233 selects at least one pulse light train L2 from the plurality of pulse light trains L2 in the pulse light train L3 emitted from the first light generation unit 22. As a result, the optical cutting unit 233 generates a pulsed light train (fourth pulse light train) L4 including at least one pulsed light train L2. Specifically, the pulsed light train L3 passes through the mirror 231 and is input to the light cutting unit 233. The light cutting unit 233 selects the pulse light train L21 or the pulse light train L22 from the plurality of pulse light trains L2 in the pulse light train L3 based on the control signal C.

When the control signal C1 is transmitted from the control unit 24, the optical cutting unit 233 blocks the pulsed light train L22 included in the pulsed light train L3 while passing through the pulsed light train L21 included in the pulsed light train L3. By doing so, a pulse light train L4 including only the pulse light train L21 is generated. Further, when the control signal C2 is transmitted from the control unit 24, the optical cutting unit 233 blocks the pulse light train L21 included in the pulse light train L3 and the pulse light train L22 included in the pulse light train L3. To generate a pulsed light train L4 including only the pulsed light train L22. The pulsed light train L4 generated by the light cutting unit 233 is amplified in the second light generation unit 23 which is a reproduction amplifier, and the amplified pulse light train L4A is emitted from the second light generation unit 23.

The gain medium 234 is arranged on the resonance optical path of the optical resonator, receives excitation energy from the excitation light source 235, and amplifies light. The gain medium 234 contains Yb: YAG and the like. The excitation light source 235 irradiates the gain medium 234 with the excitation light as excitation energy.

The reproduction amplifier will be described in more detail. The optical cutting unit 233 has an electro-optical element (not shown), a λ / 4 wave plate (not shown), a polarizing beam splitter (not shown), and the like, each of which is arranged on the optical path of the optical resonator. There is. The electro-optical element is, for example, a Pockels cell, and controls the polarization state of light by an electro-optical effect. The λ / 4 wave plate provides a 90 ° phase difference between the polarization components of the light. Polarized beam splitters selectively reflect or transmit light depending on their polarization state.

The pulsed light train L4 is reflected by the polarizing beam splitter and incorporated into the optical resonator. The pulsed light train L4 passes through the λ / 4 wave plate and the electro-optical element in the optical resonator, is reflected by the mirror 231 and then returns to the polarization beam splitter again. A driving voltage is applied to the electro-optical element between the time when the pulsed light train L4 is reflected by the polarizing beam splitter and the time when it returns to the polarizing beam splitter again. As a result, the Q value of the optical resonator increases instantaneously, and the pulsed light train L4 resonates in the optical resonator. The pulsed light train L4 absorbs the energy of the gain medium 234 while resonating, and gradually amplifies the energy to increase the peak power. After a predetermined time has elapsed since the pulsed light train L4 was confined in the optical resonator, the voltage applied to the electro-optical element is changed. As a result, the amplified pulsed light train L4A changes its polarization state, is taken out of the optical resonator, and is emitted to the outside of the laser processing light source 2.

The control unit 24 controls the operation of each unit of the laser processing light source 2. The control unit 24 has a processing unit, a storage unit, and the like. The processing unit is configured as a computer device including a processor, a memory, a storage, a communication device, and the like. In the processing unit, the processor executes software (program) read into a memory or the like, and controls reading and writing of data in the memory and storage, and communication by a communication device. The storage unit is, for example, a hard disk or the like, and stores various data.

The control unit 24 controls the second light generation unit 23. Specifically, the control unit 24 receives the electric signal E from the laser oscillation unit 21. The control unit 24 generates a control signal C based on the electric signal E. The control signal C is a signal for selecting at least one pulse light train L2 from the plurality of pulse light trains L2 in the pulse light train L3. In the present embodiment, the control signal C is a control signal C1 for selecting the pulsed light train L21 or a control signal C2 for selecting the pulsed light train L22. Each of the control signal C1 and the control signal C2 is a pulse signal having the same frequency as the electric signal E. The control unit 24 transmits the control signal C1 or the control signal C2 to the optical cutting unit 233.

The control signal C1 is generated based on the optical path length of the optical path in which the pulsed optical sequence L21 is generated in the optical path from the laser oscillating unit 21 to the optical cutting unit 233. When the control signal C1 is transmitted to the optical cutting unit 233, the pulsed light train L21 is cut out from the pulsed light train L3 input to the optical cutting unit 233. The control signal C2 is generated based on the optical path length of the optical path in which the pulsed optical sequence L22 is generated in the optical path from the laser oscillating unit 21 to the optical cutting unit 233. When the control signal C2 is transmitted to the optical cutting unit 233, the pulsed light train L22 is cut out from the pulsed light train L3 input to the optical cutting unit 233. The control signal C2 is delayed by a time difference ΔC with respect to the control signal C1.

The user interface 25 has, for example, an input receiving unit that receives input of various data from an operator. The operator can input data for selecting, for example, the pulsed light train L21 or the pulsed light train L22 into the user interface 25. The user interface 25 transmits the data to the control unit 24.

The first light generation unit 22 will be described in more detail. As shown in FIG. 3, the first optical generation unit 22 has a plurality of couplers 71, 72, 73, 74 and a plurality of optical fibers F1, F2, F3, F4, F5, F6. .. The plurality of optical fibers F2, F3, F4, F5, and F6 connect couplers adjacent to each other on the optical path.

One input end of the coupler 71 (first demultiplexing unit) is connected to the laser oscillator unit 21 by an optical fiber F1. The other input end of the coupler 71 is terminated. One output end of the coupler 71 is connected to one input end of the coupler 72 (second demultiplexing portion) by an optical fiber F2. The other output end of the coupler 71 is connected to the other input end of the coupler 74 (first combiner) by an optical fiber F3. The other input end of the coupler 72 is terminated. One output end of the coupler 72 is connected to one input end of the coupler 73 (second junction) by an optical fiber F4. The other output end of the coupler 72 is connected to the other input end of the coupler 73 by an optical fiber F5. One output end of the coupler 73 is connected to one input end of the coupler 74 by an optical fiber F6. The other output end of the coupler 73 is terminated. One output end of the coupler 74 is open. That is, no optical fiber is connected to one output end of the coupler 74. The other output end of the coupler 74 is terminated.

In the first optical generation unit 22, the couplers 72 and 73 and the optical fibers F2, F4, F5, and F6 form the first optical path, and the optical fiber F3 constitutes the second optical path. Further, the optical fiber F4 constitutes the third optical path, and the optical fiber F5 constitutes the fourth optical path. The optical path length of the first optical path and the optical path length of the second optical path are different from each other. The optical path length of the second optical path is larger than the optical path length of the first optical path. The optical path length of the third optical path and the optical path length of the fourth optical path are different from each other. The optical path length of the fourth optical path is larger than the optical path length of the third optical path.

The coupler 71 demultiplexes the pulsed light train L1 into two pulsed light trains. The first optical path and the second optical path propagate each of the two pulsed optical paths. The coupler 74 generates a pulsed light train L3 by merging the two pulsed light trains propagating in the first optical path and the second optical path. The coupler 72 demultiplexes one of the two pulsed light trains demultiplexed by the coupler 71 into two subpulse light trains. The third optical path and the fourth optical path propagate each of the two subpulse optical sequences. The coupler 73 combines the two subpulse optical sequences propagating in the third optical path and the fourth optical path. The coupler 74 generates a pulsed light train L3 by combining the other of the two pulsed light trains demultiplexed by the coupler 71 and the pulsed light trains combined by the coupler 73.

Specifically, the pulsed light train L1 emitted from the laser oscillator 21 propagates through the optical fiber F1 and is incident on the coupler 71. The pulse light train L1 is demultiplexed by the coupler 71 into the pulse light train L21 and the pulse light train L23. The pulsed light train L21 propagates through the optical fiber F3 and is incident on the coupler 74. The pulsed light train L23 propagates through the optical fiber F2 and is incident on the coupler 72. The pulsed light train L23 is demultiplexed by the coupler 72 into a pulsed light train (sub-pulse light train) L24 and a pulsed light train (sub-pulse light train) L25. The pulsed light train L24 propagates through the optical fiber F4 and is incident on the coupler 73. The pulsed light train L25 propagates through the optical fiber F5 and is incident on the coupler 73. The pulsed light train L24 and the pulsed light train L25 are combined with the pulsed light train L22 by the coupler 73. The pulsed light train L22 propagates through the optical fiber F6 and is incident on the coupler 74. The pulsed light train L22 and the pulsed light train L21 are combined by the coupler 74. As a result, a pulsed light train L3 including two pulsed light trains L2 is generated.

As described above, the optical path length of the fourth optical path (that is, the optical path length of the optical fiber F5) is larger than the optical path length of the third optical path (that is, the optical path length of the optical fiber F4). Therefore, the phase of the pulsed light train L25 emitted from the fourth optical path is delayed with respect to the phase of the pulsed light train L24 emitted from the third optical path. Therefore, in the pulsed light train L22 combined by the coupler 73, the one-pulse light becomes a double-pulse light composed of two pulses arranged with a time difference τ1. The time difference τ1 is a value obtained by dividing the optical path difference between the third optical path and the fourth optical path by the speed of light, and is, for example, about several hundred ps. As described above, the pulsed light train L22 is a double pulsed light train composed of a plurality of double pulsed lights. The double-pulse light is, for example, one-pulse light composed of two pulses that are close in time to several ps to 20 ns.

The optical path length of the second optical path (that is, the optical path length of the optical fiber F3) is the optical path length of the optical path composed of the couplers 72 and 73 and the optical fibers F2, F4, and F6. In addition, it is larger than the optical path length of the optical path composed of the couplers 72 and 73 and the optical fibers F2, F5, and F6). Therefore, the phase of the pulsed light train L21 emitted from the second optical path is delayed with respect to the phase of the pulsed light train L22 emitted from the first optical path. Therefore, in the pulsed light train L3 combined by the coupler 74, the plurality of single pulsed lights included in the pulsed light train L21 and the plurality of double pulsed lights included in the pulsed light train L22 are alternately arranged with a time difference τ2. It will be. The time difference τ2 is a value obtained by dividing the optical path difference between the first optical path and the second optical path by the speed of light, and is, for example, about 12.5 ns. The time difference τ2 is the same as the time difference ΔC. The single pulse light is a one-pulse light composed of one pulse.

An example of the frequency and power of each pulsed light train (power of one pulsed light) will be described. The pulsed light train L1 having a frequency of 40 MHz and a power of 100 mW is divided into a pulsed light train L23 having a frequency of 40 MHz and a power of 80 mW and a pulsed light train L21 having a frequency of 40 MHz and a power of 20 mW by a coupler 71. Be waved. The pulse light train L23 having a frequency of 40 MHz and a power of 80 mW is divided into a pulse light train L24 having a frequency of 40 MHz and a power of 40 mW and a pulse light train L25 having a frequency of 40 MHz and a power of 40 mW by a coupler 72. Be waved.

The pulsed light train L24 having a frequency of 40 MHz and a power of 40 mW and the pulsed light train L25 having a frequency of 40 MHz and a power of 40 mW are combined with the pulsed light train L22 having a frequency of 40 MHz and a power of 40 mW by the coupler 73. Be waved. The pulsed light train L22 having a frequency of 40 MHz and a power of 40 mW and the pulsed light train L21 having a frequency of 40 MHz and a power of 20 mW are combined with the pulsed light train L3 having a frequency of 80 MHz and a power of 30 mW by the coupler 74. Be waved. The pulsed light train L4A (see FIG. 2) amplified in the second light generation unit 23, which is a reproduction amplifier, and emitted from the second light generation unit 23 has a frequency of 20 to 500 kHz and a power of 4 to 20 W. Have.

As described above, the laser processing light source 2 generates a pulsed light train L3 including a plurality of pulsed light trains L2. In the pulsed light train L3, the pulsed light train L21 or the pulsed light train L22 is selected from the plurality of pulsed light trains L2. As a result, the pulsed light train L4 including the pulsed light train L21 or the pulsed light train L22 is generated. Therefore, according to the laser processing light source 2, it is possible to selectively emit a plurality of types of pulsed light trains.

It may be required that both the double pulse light train having a time difference of about several hundred ps and the single pulse light train are emitted by the same laser processing light source. Therefore, the present inventors have found the light source 2 for laser processing as described above. That is, according to the laser processing light source 2, it is possible to switch between the double pulse light train and the single pulse light train only by changing the control signal C without changing the hard wafer, and it is highly reliable for industrial use. , Highly stable and highly efficient equipment can be provided. It was confirmed that the optical characteristics (average output, energy stability, beam pattern) at the time of output of the single pulse light train were maintained even at the time of output of the double pulse light train. Further, according to the laser processing light source 2, it is possible to perform processing using a double pulse light train only by replacing the laser processing light source 2 while keeping the existing processing optical system such as the irradiation optical system 3 alive. It will be possible.

Further, in the laser processing light source 2, the laser oscillator 21 transmits an electric signal E having a frequency corresponding to the pulsed light train L1 to the control unit 24. The control unit 24 generates a control signal C based on the electric signal E. According to this configuration, in the pulsed light train L3, the second light generation unit 23 that selects the pulsed light train L21 or the pulsed light train L22 from the plurality of pulsed light trains L2 can be accurately and easily controlled.

Further, in the laser processing light source 2, the second light generation unit 23 constitutes an optical resonator together with the light cutting unit 233 that generates the pulsed light train L4 and the light cutting unit 233 for the pulsed light train L4. It is a reproduction amplifier having a gain medium 234 and an excitation light source 235 that irradiates the gain medium 234 with excitation light. According to this configuration, the pulsed light train L4 can be efficiently generated and amplified.

Further, in the laser processing light source 2, each of the plurality of pulsed light trains L2 is a single pulse light train (pulse light train L21) and a double pulse light train (pulse light train L22). According to this configuration, in the pulse light train L3, for example, by selecting a single pulse light train or a double pulse light train from a plurality of pulse light trains L2, a pulse light train including a single pulse light train or a double pulse light train is included. L4 can be generated.

Further, in the laser processing light source 2, the first light generation unit 22 includes a coupler 71, a first optical path and a second optical path, and a coupler 74. The coupler 71 demultiplexes the pulsed light train L1 into two pulsed light trains L21 and L23. The first optical path and the second optical path have different optical path lengths, and propagate each of the two pulsed light trains L21 and L23. The coupler 74 generates the pulsed light train L3 by combining the two pulsed light trains L21 and L22. The first optical path has a coupler 74, a third optical path, a fourth optical path, and a coupler 73. The coupler 74 demultiplexes the pulsed light train L23 demultiplexed by the coupler 71 into two pulsed light trains L24 and L25. The third optical path and the fourth optical path have different optical path lengths, and propagate each of the two pulse optical sequences L24 and L25. The coupler 73 combines two pulsed light trains L24 and L25. The first confluence section combines the other of the two pulsed light trains demultiplexed by the first demultiplexing part and the pulsed light train demultiplexed by the second demultiplexing part to combine the third pulsed light. You may generate columns. According to this configuration, the pulsed light train L3 can be easily generated.

Further, in the laser processing light source 2, the first demultiplexing portion, the first demultiplexing portion, the second demultiplexing portion, and the second demultiplexing portion are couplers 71, 72, 73, and 74, respectively. The first optical generation unit 22 has optical fibers F2, F3, F4, F5, and F6 that connect couplers adjacent to each other on the optical path. According to this configuration, the pulsed light train L3 can be generated more easily.

That is, since the first light generation unit 22 is composed of widely used fiber optical components, active control and special optical elements are not required. As a result, it is possible to realize an inexpensive, highly reliable and highly stable structure. Further, the optical characteristics can be improved as compared with the case where the first light generating unit is configured by, for example, a polarizing beam splitter. That is. Since the polarization directions of the pulsed light trains L22, which are double-pulse light trains, coincide with each other, it is possible to suppress a decrease in light utilization efficiency due to, for example, adjusting the polarization state. Further, since it is suppressed that the distance from the laser oscillator 21 to the workpiece P becomes long, the deterioration of the long-term stability of the apparatus is suppressed. In addition, regular alignment adjustment is not required. Further, since the pulsed light trains L22 propagate through optical paths that completely coincide with each other, it is not necessary to completely match a plurality of lights at the condensing point.

Further, in the laser processing light source 2, the first light generation unit 22 and the second light generation unit 23 are arranged through the space through which the pulsed light train L3 propagates. According to this configuration, the first light generating unit 22 can be easily attached and detached independently of the second light generating unit 23.

According to the laser processing apparatus 1, it is possible to selectively irradiate the workpiece P with a plurality of types of pulsed light trains L4. As a result, the workpiece P can be appropriately processed according to various uses.

[Second Embodiment]
As shown in FIG. 4, the laser processing light source of the second embodiment includes the first light generation unit 22A instead of the first light generation unit 22, and the laser processing light source of the first embodiment is provided. Is mainly different. The first optical generation unit 22A includes a plurality of couplers 81 to 88 and a plurality of optical fibers F11 to F22. The plurality of optical fibers F12 to F22 connect couplers adjacent to each other on the optical path.

One input end of the coupler 81 is connected to the laser oscillator 21 by an optical fiber F11. The other input end of the coupler 81 is terminated. One output end of the coupler 81 is connected to one input end of the coupler 82 by an optical fiber F12. The other output end of the coupler 81 is connected to the other input end of the coupler 86 by an optical fiber F13. The other input end of the coupler 82 is terminated. One output end of the coupler 82 is connected to one input end of the coupler 83 by an optical fiber F14. The other output end of the coupler 82 is connected to one input end of the coupler 87 by an optical fiber F15.

The other input end of the coupler 83 is terminated. One output end of the coupler 83 is connected to one input end of the coupler 84 by an optical fiber F16. The other output end of the coupler 83 is connected to the other input end of the coupler 84 by an optical fiber F17. One output end of the coupler 84 is connected to one input end of the coupler 85 by an optical fiber F18. The other output end of the coupler 84 is terminated.

The other input end of the coupler 87 is terminated. One output end of the coupler 87 is connected to one input end of the coupler 88 by an optical fiber 20. The other output end of the coupler 87 is connected to the other input end of the coupler 88 by an optical fiber F21. One output end of the coupler 88 is connected to the other input end of the coupler 85 by an optical fiber F22. The other output end of the coupler 88 is terminated.

One output end of the coupler 85 is connected to one input end of the coupler 86 by an optical fiber F19. The other output end of the coupler 85 is terminated. One output end of the coupler 86 is open. That is, no optical fiber is connected to one output end of the coupler 86. The other output end of the coupler 86 is terminated.

In the first optical generation unit 22A, the first optical path is configured by the couplers 82, 83, 84, 85 and the optical fibers F12, F14, F16, F17, F18, F19, and the second optical path is configured by the optical fiber F13. Has been done. Further, the optical fiber F16 constitutes the third optical path, and the optical fiber F17 constitutes the fourth optical path. Further, the fifth optical path is composed of the couplers 87 and 88 and the optical fibers F15, F20, F21 and F22, and the eighth optical path is composed of the couplers 83 and 84 and the optical fibers F14, F16, F17 and F18. Further, the optical fiber F20 constitutes the sixth optical path, and the optical fiber F21 constitutes the seventh optical path.

The optical path length of the first optical path and the optical path length of the second optical path are different from each other. The optical path length of the second optical path is larger than the optical path length of the first optical path. The optical path length of the third optical path and the optical path length of the fourth optical path are different from each other. The optical path length of the fourth optical path is larger than the optical path length of the third optical path. The optical path length of the fifth optical path and the optical path length of the eighth optical path are different from each other. The optical path length of the fifth optical path is larger than the optical path length of the eighth optical path. The optical path length of the 6th optical path and the optical path length of the 7th optical path are different from each other. The optical path length of the 7th optical path is larger than the optical path length of the 6th optical path.

The pulsed light train L1 emitted from the laser oscillator 21 propagates through the optical fiber F11 and is incident on the coupler 81. The pulse light train L1 is demultiplexed by the coupler 81 into the pulse light train L31 (pulse light train L2) and the pulse light train L34. The pulsed light train L31 propagates through the optical fiber F13 and is incident on the coupler 86. The pulsed light train L34 propagates through the optical fiber F12 and is incident on the coupler 82.

The pulse light train L34 is demultiplexed by the coupler 82 into the pulse light train L35 and the pulse light train L36. The pulsed light train L35 propagates through the optical fiber F14 and is incident on the coupler 83. The pulsed light train L35 is demultiplexed by the coupler 83 into a pulsed light train (sub-pulse light train) L37 and a pulsed light train (sub-pulse light train) L38. The pulsed light train L37 propagates through the optical fiber F16 and is incident on the coupler 84. The pulsed light train L38 propagates through the optical fiber F17 and is incident on the coupler 84. The pulsed light train L37 and the pulsed light train L38 are combined with the pulsed light train L32 (pulse light train L2) by the coupler 84. The pulsed light train L32 propagates through the optical fiber F18 and is incident on the coupler 85.

The pulsed light train L36 propagates through the optical fiber F15 and is incident on the coupler 87. The pulsed light train L36 is demultiplexed by the coupler 87 into a pulsed light train (sub-pulse light train) L39 and a pulsed light train (sub-pulse light train) L40. The pulsed light train L39 propagates through the optical fiber F20 and is incident on the coupler 88. The pulsed light train L40 propagates through the optical fiber F21 and is incident on the coupler 88. The pulsed light train L39 and the pulsed light train L40 are combined with the pulsed light train L33 (pulse light train L2) by the coupler 88. The pulsed light train L33 propagates through the optical fiber F22 and is incident on the coupler 85.

The pulsed light train L32 and the pulsed light train L33 are combined with the pulsed light train L30 by the coupler 85. The pulsed light train L30 propagates through the optical fiber F19 and is incident on the coupler 86. The pulsed light train 31 and the pulsed light train L30 are combined with the pulsed light train L3 by the coupler 86. As a result, a pulsed light train L3 including three pulsed light trains L2 is generated.

As described above, the optical path length of the fourth optical path (that is, the optical path length of the optical fiber F17) is larger than the optical path length of the third optical path (that is, the optical path length of the optical fiber F16). Therefore, the phase of the pulsed light train L38 emitted from the fourth optical path is delayed with respect to the phase of the pulsed light train L37 emitted from the third optical path. Therefore, in the pulsed light train L32 combined by the coupler 84, the one-pulse light becomes a double-pulse light composed of two pulses arranged with a time difference τ3. The time difference τ3 is a value obtained by dividing the optical path difference between the third optical path and the fourth optical path by the speed of light, and is, for example, about several hundred ps. As described above, the pulsed light train L32 is a double pulsed light train composed of a plurality of double pulsed lights.

Similarly, the optical path length of the seventh optical path (that is, the optical path length of the optical fiber F21) is larger than the optical path length of the sixth optical path (that is, the optical path length of the optical fiber F20). Therefore, the phase of the pulsed light train L40 emitted from the 7th optical path is delayed with respect to the phase of the pulsed light train L39 emitted from the 6th optical path. Therefore, in the pulsed light train L33 combined by the coupler 88, the one-pulse light becomes a double-pulse light composed of two pulses arranged with a time difference τ4. The time difference τ4 is a value obtained by dividing the optical path difference between the sixth optical path and the seventh optical path by the speed of light, and is, for example, about several hundred ps. As described above, the pulsed light train L33 is a double pulsed light train composed of a plurality of double pulsed lights.

The optical path length of the fifth optical path (that is, the optical path length of the optical path composed of the couplers 87 and 88 and the optical fibers F15, F20 and F22, and the optical path composed of the couplers 87 and 88 and the optical fibers F15, F21 and F22. The optical path length) is determined by the optical path length of the eighth optical path (that is, the optical path length of the optical path composed of the couplers 83, 84 and the optical fibers F14, F16, F18, and the couplers 83, 84 and the optical fibers F14, F17, F18. It is larger than the optical path length of the constructed optical path). Therefore, the phase of the pulsed light train L33 emitted from the fifth optical path is delayed with respect to the phase of the pulsed light train L32 emitted from the eighth optical path. Therefore, in the pulsed light train L30 combined by the coupler 85, the plurality of double pulsed lights included in the pulsed light train L32 and the plurality of double pulsed lights included in the pulsed light train L33 are alternately arranged with a time difference τ5. become. The time difference τ5 is a value obtained by dividing the optical path difference between the fifth optical path and the eighth optical path by the speed of light, and is, for example, about 8.3 ns.

Similarly, the optical path length of the second optical path (that is, the optical path length of the optical path configured by the optical fiber F13) is the optical path length of the first optical path (that is, the couplers 82, 83, 84, 85 and the optical fibers F12, F14, It is larger than the optical path length of the optical path composed of F16, F18, and F19, and the optical path length of the optical path composed of the couplers 82, 83, 84, 85 and the optical fibers F12, F14, F17, F18, and F19. Therefore, the phase of the pulsed light train L31 emitted from the second optical path is delayed with respect to the phase of the pulsed light train L30 emitted from the first optical path. Therefore, in the pulsed light train L3 combined by the coupler 86, the plurality of double pulsed lights included in the pulsed light train L31 and the plurality of double pulsed lights included in the pulsed light train L30 are alternately arranged with a time difference τ6. become. The time difference τ6 is a value obtained by dividing the optical path difference between the first optical path and the second optical path by the speed of light, and is, for example, about 8.3 ns.

An example of the frequency and power of each pulsed light train (power of one pulsed light) will be described. The pulsed light train L1 having a frequency of 40 MHz and a power of 100 mW is divided into a pulsed light train L34 having a frequency of 40 MHz and a power of 80 mW and a pulsed light train L31 having a frequency of 40 MHz and a power of 20 mW by a coupler 81. Be waved. The pulse light train L34 having a frequency of 40 MHz and a power of 80 mW is divided into a pulse light train L35 having a frequency of 40 MHz and a power of 40 mW and a pulse light train L36 having a frequency of 40 MHz and a power of 40 mW by a coupler 82. Be waved.

The pulsed light train L35 having a frequency of 40 MHz and a power of 40 mW is divided into a pulsed light train L37 having a frequency of 40 MHz and a power of 20 mW and a pulsed light train L38 having a frequency of 40 MHz and a power of 20 mW by a coupler 83. Be waved. The pulsed light train L37 having a frequency of 40 MHz and a power of 20 mW and the pulsed light train L38 having a frequency of 40 MHz and a power of 20 mW are combined with the pulsed light train L32 having a frequency of 40 MHz and a power of 20 mW by the coupler 84. Be waved.

The pulsed light train L36 having a frequency of 40 MHz and a power of 40 mW is divided into a pulsed light train L39 having a frequency of 40 MHz and a power of 20 mW and a pulsed light train L40 having a frequency of 40 MHz and a power of 20 mW by the coupler 87. Be waved. The pulsed light train L39 having a frequency of 40 MHz and a power of 20 mW and the pulsed light train L40 having a frequency of 40 MHz and a power of 20 mW are combined with the pulsed light train L33 having a frequency of 40 MHz and a power of 20 mW by the coupler 88. Be waved.

The pulsed light train L32 having a frequency of 40 MHz and a power of 20 mW and the pulsed light train L33 having a frequency of 40 MHz and a power of 20 mW are combined with the pulsed light train L30 having a frequency of 80 MHz and a power of 20 mW by the coupler 85. Be waved. The pulsed light train L30 having a frequency of 80 MHz and a power of 20 mW and the pulsed light train L31 having a frequency of 40 MHz and a power of 20 mW are combined with the pulsed light train L3 having a frequency of 120 MHz and a power of 20 mW by the coupler 86. Be waved.

[Modification example]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments.

As shown in FIG. 5, the laser processing light source of the first embodiment may include a first light generation unit 22B instead of the first light generation unit 22. The first light generation unit 22B is mainly different from the first light generation unit 22 in that it has a coupler 72B instead of the coupler 72. The branching ratio of the coupler 72B is different from the branching ratio of the coupler 72. As an example, the pulsed light train L23 having a frequency of 40 MHz and a power of 80 mW has a pulsed light train L24B having a frequency of 40 MHz and a power of 60 mW and a pulsed light train L25B having a frequency of 40 MHz and a power of 20 mW by a coupler 72B. It may be demultiplexed to. In this case, in the pulsed light train L22B combined by the coupler 73, one pulse of light becomes double pulsed light composed of two pulses having different powers.

As shown in FIG. 6, the laser processing light source of the second embodiment may include a first light generation unit 22C instead of the first light generation unit 22A. The first optical generation unit 22C has the optical fiber F23 in place of the fifth optical path (the optical path composed of the couplers 87 and 88 and the optical fibers F15, F20, F21 and F22), and the first optical generation unit 22C generates the first light. It is mainly different from the part 22A.

The other output end of the coupler 82 is connected to the other input end of the coupler 85 by an optical fiber F23. The pulsed light train 36 output from the coupler 82 propagates through the optical fiber F23 and is incident on the coupler 85. The pulse light train L32 and the pulse light train 36 are combined with the pulse light train L37 (pulse light train L2) by the coupler 85. In the first optical generation unit 22C, the ninth optical path is configured by the optical fiber F23. The optical path length of the ninth optical path (that is, the optical path length of the optical fiber F23) is the optical path length of the optical path composed of the couplers 83, 84 and the optical paths F14, F16, F18, and the optical path length of the eighth optical path. It is different from the optical path length of the optical path composed of the couplers 83 and 84 optical fibers F14, F17 and F18). The optical path length of the ninth optical path is larger than the optical path length of the eighth optical path. Therefore, in the pulsed light train L37 combined by the coupler 85, one pulse of light becomes, for example, triple-pulse light composed of three pulses arranged with the same time difference.

In each embodiment, the branching ratio of each coupler (ratio of the power of each demultiplexed pulsed light train) and the length of each optical fiber may be adjusted as needed.

In each embodiment, the second light generating unit 23 may have at least a light cutting unit 233. That is, the second light generation unit 23 does not have to be a reproduction amplifier. The second light generation unit 23 may include, for example, a light cutout unit 233, one gain medium, and one excitation light source. That is, the second light generation unit 23 may be a single-pass amplifier. In this case, the pulsed light train L4 generated by the light cutting unit 233 is amplified by passing through one gain medium. Further, the second light generation unit 23 may have a light cutout unit 233, a plurality of gain media, and a plurality of excitation light sources. That is, the second light generation unit 23 may be a MOPA amplifier. In this case, the pulsed light train L4 generated by the light cutting unit 233 is amplified by passing through a plurality of gain media.

In each embodiment, an example in which the first light generation unit 22 is composed of a coupler and an optical fiber is shown, but the first light generation unit 22 may be composed of an optical system such as a beam splitter or the like. The first light generation unit 22 generates a pulse light train L3 including a plurality of pulse light trains L2 by performing demultiplexing, propagation in a plurality of optical paths, and conjugation with respect to the pulse light train L1. Just do it.

In each embodiment, an example is shown in which the first light generation unit 22 generates a pulse light train L3 including two or three types of pulse light trains L2, but the first light generation unit 22 has n (n is 3). A pulsed light train L3 containing a type of pulsed light train L2 may be generated. The optical cutting unit 233 selects m (m is an integer of n or less) types of pulsed light trains L2 from n types of pulsed light trains L2 in the pulsed light train L3, thereby selecting m types of pulsed light trains L2. The pulsed light train L4 containing the above may be generated. If the light cutting unit 233 selects at least one pulse light train L2 from the plurality of pulse light trains L2 in the pulse light train L3 to generate a pulse light train L4 including at least one pulse light train L2. Good.

1 ... Laser processing device, 2 ... Laser processing light source, 3 ... Irradiation optical system (irradiation unit), 4 ... Support unit, 21 ... Laser oscillation unit, 22 ... First light generation unit, 23 ... Second light generation unit, 24 ... Control unit, 71 ... Coupler (1st demultiplexing part), 72 ... Coupler (2nd demultiplexing part), 73 ... Coupler (2nd demultiplexing part), 74 ... Coupler (1st demultiplexing part), 233 ... Optical cutting unit, 234 ... Gain medium, 235 ... Excitation light source, C, C1, C2 ... Control signal, E ... Electrical signal, L1 ... Pulse light train (first pulse light train), L2 ... Pulse light train (No. 1) 2 pulsed light train), L3 ... pulsed light train (3rd pulse light train), L4 ... pulsed light train (4th pulse light train), L21, L23 ... pulsed light train, L24, L25 ... pulsed light train (subpulse light) Row), P ... Work piece.

Claims (8)

A laser oscillator that emits a first pulse light train,
A first light generation that generates a third pulse light train including a plurality of second pulse light trains by demultiplexing, propagating in a plurality of optical paths, and merging the first pulse light train. Department and
In the third pulse light train, by selecting at least one second pulse light train from the plurality of second pulse light trains, a fourth pulse light train including the at least one second pulse light train is generated. The second light generator and
A control unit that controls the second light generation unit is provided.
The control unit transmits a control signal for selecting at least one second pulse light train from the plurality of second pulse light trains to the second light generation unit in the third pulse light train. Light source for processing. The laser oscillator unit transmits an electric signal having a frequency corresponding to the first pulse light train to the control unit.
The laser processing light source according to claim 1, wherein the control unit generates the control signal based on the electric signal. The second light generator
An optical cutout portion that generates the fourth pulse optical train, and
A gain medium that constitutes an optical resonator together with the optical cutout portion for the fourth pulse optical train,
The light source for laser processing according to claim 1 or 2, which is a reproduction amplifier having an excitation light source for irradiating the gain medium with excitation light. The light source for laser processing according to any one of claims 1 to 3, wherein each of the plurality of second pulse light trains is a single pulse light train and a double pulse light train. The first light generator
A first demultiplexing unit that demultiplexes the first pulse light train into two pulse light trains,
The first optical path and the second optical path, which have different optical path lengths and propagate each of the two pulsed optical paths,
It has a first confluence unit that generates the third pulse light train by merging the two pulse light trains.
The first optical path is
A second demultiplexing unit that demultiplexes one of the two pulsed light trains demultiplexed by the first demultiplexing unit into two subpulse light trains, and
The third and fourth optical paths, which have different optical path lengths and propagate each of the two subpulse optical paths,
It has a second merging section that merging the two subpulse light trains, and
The first confluence unit combines the other of the two pulse light trains demultiplexed by the first demultiplexing unit and the pulse light train demultiplexed by the second demultiplexing unit. The laser processing light source according to any one of claims 1 to 4, which generates the third pulse light train. Each of the first demultiplexing section, the first demultiplexing section, the second demultiplexing section, and the second demultiplexing section is a coupler.
The light source for laser processing according to claim 5, wherein the first light generation unit further includes an optical fiber that connects the couplers adjacent to each other on the optical path. The light source for laser processing according to any one of claims 1 to 6, wherein the first light generation unit and the second light generation unit are arranged through a space through which the third pulse light train propagates. .. The light source for laser processing according to any one of claims 1 to 7,
A support part that supports the work piece and
A laser processing apparatus including an irradiation unit that irradiates the workpiece with a pulsed light train emitted from the laser processing light source.

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