KR20220124296A - Wavelength conversion laser device and wavelength conversion laser processing machine - Google Patents

Abstract

By changing the pulse frequency of the laser light, which was a problem with the conventional wavelength conversion device, the average output after wavelength conversion changes and the angle of the laser light emitted from the nonlinear medium changes, and the laser light 3 is generated. A pulsed laser light source 1 for controlling the pulse frequency, a pulse frequency control means 2 for controlling the pulse frequency, a non-linear medium 8 for wavelength-converting a part of the laser light 3 into a laser light 9, and a laser light ( 3) the condensing lens 7 for condensing, the collimating lens 10 for adjusting the diffusion angle of the laser light 9, and the laser light 9 passing through the collimating lens 10 is incident In addition, a parallel flat plate 13 transmitted through and emitted, and an angle adjusting mechanism 14 for controlling the incident angle of the laser beam 9 incident on the parallel flat plate 13 are provided.

Description

Wavelength conversion laser device and wavelength conversion laser processing machine

This disclosure relates to a wavelength conversion laser device and a wavelength conversion laser processing machine that convert laser light into different wavelengths using a nonlinear medium.

BACKGROUND ART A wavelength conversion laser device that emits a laser beam having a wavelength different from the wavelength of the incident laser beam by making the laser beam incident on a nonlinear medium is known. This wavelength conversion laser device generates a second harmonic having a wavelength of half that of the fundamental wave by making a laser light, which is a fundamental wave, incident on a first nonlinear medium, and also by injecting the fundamental wave and the second harmonic into a second nonlinear medium, A third harmonic with a wavelength of one third of the fundamental is generated. A solid nonlinear medium for wavelength conversion is called a wavelength conversion crystal. In the inside of the nonlinear medium, when the sum of the wavenumber vectors of the laser light before the wavelength conversion coincides with the wavenumber vector of the laser light after the wavelength conversion, strong wavelength conversion occurs. In the generation of the third harmonic, the strongest third harmonic is obtained when the following equation is satisfied.

[Number 1]

k _ω , k _2ω , and k _3ω are wavenumber vectors of the fundamental, second, and third harmonics, respectively. This condition is called a phase matching condition. The direction of the wavenumber vector is a direction perpendicular to the equiphase plane of the laser beam, and is usually the traveling direction of the laser beam. Incidentally, the magnitude of the wavenumber vector is expressed by the following equation.

[Number 2]

k is the magnitude of the wave number vector, n is the refractive index of the nonlinear medium, and λ is the wavelength of the laser light. Since the refractive index n of a nonlinear medium depends on the temperature of the nonlinear medium, the wavenumber vector changes with the temperature of the nonlinear medium. Therefore, in order to satisfy the phase matching condition, it is necessary to control the temperature of the nonlinear medium.

A wavelength conversion laser device is used as a light source for microfabrication. In order to raise a processing speed, the pulse frequency of a laser beam may be changed in the middle of a processing, and when the pulse frequency of a fundamental wave is changed, the pulse frequency of a 3rd harmonic will also change. The conversion efficiency of wavelength conversion depends on the pulse energy of the laser light incident on the nonlinear medium. Since the pulse energy contained in one pulse will become low when a pulse frequency is raised when the average output of a fundamental wave is constant, the average output of the laser beam after wavelength conversion will become low.

In a high-power laser device, an optical component constituting the laser device or a holder for fixing the optical component absorbs a laser beam to generate heat, and the optical axis of the laser beam may change due to this heat generation. In order to suppress the optical axis change of a laser beam, the laser apparatus using the angle-adjustable holder which mounted the actuator is disclosed.

Patent Document 1: Japanese Patent Application Laid-Open No. 2014-170839 (Page 12, Fig. 2)

In the case of absorption of laser light in a nonlinear medium, if the pulse frequency of the laser light is changed, the average output after wavelength conversion changes, and since the amount of heat absorbed by the nonlinear medium changes, the temperature of the nonlinear medium changes. When the temperature of the nonlinear medium changes, the refractive index of the nonlinear medium changes with the temperature change, so that the wavenumber vector changes. As a result, the traveling direction of the laser beam satisfying the phase matching condition changes, and the emission angle of the laser beam emitted from the nonlinear medium changes. Since the change in the emission angle of the laser light emitted from the nonlinear medium depends on the temperature change of the nonlinear medium, it is not an instantaneous change, but requires a time of several seconds to several tens of seconds. Therefore, in order to perform angle adjustment of a laser beam using an angle-adjustable holder mounted with an actuator as disclosed in a conventional laser device, one angle-adjustable holder cannot cope, and two or more angles are not supported. There is a problem that an adjustable holder is required, which leads to an increase in size and cost of the laser device.

This disclosure has been made in order to solve the above-mentioned problems, and by changing the pulse frequency of the laser light, it is possible to cope with the output change of the laser light after wavelength conversion, and the wavelength conversion capable of suppressing the optical axis change of the laser light only with a single optical axis adjustment mechanism It aims to obtain a laser device.

The wavelength conversion laser device according to the present disclosure includes a pulsed laser light source for generating a first laser light, a pulse frequency control means for controlling a pulse frequency of the first laser light generated by the pulsed laser light source as a pulse, and a part of the first laser light. A nonlinear medium for wavelength conversion into a second laser light, a condensing lens for condensing the first laser light, a collimating lens for adjusting the diffusion angle of the second laser light, and a second laser light passing through the collimating lens It is provided with the angle adjustment mechanism which controls the incident angle of the parallel flat plate which enters, transmits and exits, and the 2nd laser beam which injects into the parallel flat plate.

This disclosure converts the change in the emission angle of laser light emitted from the nonlinear medium, which is generated according to the temperature change of the nonlinear medium, into a parallel movement of the optical axis by the collimating lens. Moreover, the optical axis of the laser beam which has moved parallel is corrected by the optical axis movement by the parallel flat plate angle-adjusted by the angle adjustment mechanism. As a result, even if the pulse frequency of the pulsed laser light source is changed by the pulse frequency control means, the effect that the amount of optical axis movement of the laser beam emitted from the nonlinear medium can be suppressed is achieved.

1 is a configuration diagram of a wavelength conversion laser device showing Example 1 of this disclosure.
2 is a configuration diagram of a pulsed laser light source showing Example 1 of this disclosure.
3 is a configuration diagram of another form of a pulsed laser light source showing Example 1 of this disclosure.
Fig. 4 is an optical diagram in which each laser beam travels inside a third harmonic generating crystal showing Example 1 of the present disclosure.
Fig. 5 is an explanatory diagram showing the optical axis movement of the third harmonic as it passes through the parallel flat plate showing the first embodiment of the present disclosure.
6 is an explanatory diagram showing the optical axis movement of the third harmonic after passing through the third harmonic generation crystal by the collimating lens according to the first embodiment of the present disclosure.
7 : is a measurement result of the time change of the optical axis of 3rd harmonic when the pulse frequency which shows Example 1 of this indication is changed.
Fig. 8 is an explanatory diagram showing correction of the optical axis change of the third harmonic by adjusting the angle of the parallel flat plate according to the first embodiment of the present disclosure.
Fig. 9 is a diagram showing the change with time of the adjustment amount of the angle of the optical axis by the parallel flat plate after changing the pulse frequency according to the first embodiment of the present disclosure;
10 is a calculation result of the correction amount in the case of correcting the optical axis movement of the third harmonic generated after passing through the collimating lens according to Example 1 of the present disclosure by adjusting the angle of the parallel flat plate.
11 is a configuration diagram of a wavelength conversion laser device showing Example 2 of this disclosure.
It is explanatory drawing which shows correction|amendment of the optical axis change of the 3rd harmonic by the parallel movement of the parallel movement mechanism which shows Example 2 of this indication.
13 is a configuration diagram of a wavelength conversion laser device showing Example 3 of this disclosure.
Fig. 14 is an explanatory diagram showing a state in which a beam diameter is enlarged by a prism according to a third embodiment of the present disclosure.
It is explanatory drawing which shows the correction|amendment of the optical axis change of the 3rd harmonic by the parallel movement of the parallel movement mechanism which shows Example 3 of this indication.
Fig. 16 is a configuration diagram of a wavelength conversion laser processing machine showing a fourth embodiment of this disclosure.
17 : is intensity distribution of the laser beam just before passing through the mask which shows Example 4 of this indication.
18 is an intensity distribution of laser light after passing through the mask before changing the pulse frequency for driving the wavelength conversion laser device showing Example 4 of this disclosure.
19 is an intensity distribution of a laser beam when the optical axis of the laser beam after passing through the mask showing Example 4 of this indication shifts from the center position of the mask.
20 is an intensity distribution of the laser beam of the laser beam 502 after passing through the mask after changing the pulse frequency for driving the wavelength conversion laser device according to Example 4 of this disclosure.

Example 1.

1 is a configuration diagram of a wavelength conversion laser device showing Example 1 of this disclosure. The wavelength conversion laser device 50 shown in Fig. 1 includes a pulsed laser light source 1, a pulse frequency control means 2, a condensing lens 4, a second harmonic generating crystal 5 as a nonlinear medium, A condensing lens 7, a third harmonic generating crystal 8 as a nonlinear medium, a collimating lens 10, a parallel flat plate 13, and an angle adjustment mechanism 14 of the parallel flat plate are provided. . The pulse laser light source 1 outputs the laser beam 3 used as the fundamental wave which is a 1st laser beam. The pulse frequency of the pulsed laser light source 1 which performs pulse oscillation can be changed by the pulse frequency control means 2 . The laser beam 3 output from the pulse laser light source 1 is a single mode.

2 is a configuration diagram of a pulsed laser light source showing Example 1 of this disclosure. The pulse laser light source 1 shown in FIG. 2 is a Q-switched laser. The pulse laser light source 1 includes a high reflection mirror 101 that fully reflects the laser light 110 and a partial reflection mirror 102 that reflects some of the laser light 110 and transmits the rest. do. Between the highly reflective mirror 101 and the partially reflective mirror 102 , a laser medium 103 , an excitation light coupling mirror 104 , and an acoustooptical element 105 are disposed. The excitation light 108 generated by the light source 106, which is a semiconductor laser, and passed through the optical fiber 107, passes through the excitation optical system 109 and the excitation light coupling mirror 104 to pass through the laser medium 103. investigate

The laser medium 103 absorbs the excitation light 108 to generate natural emission light that is the wavelength of the fundamental wave. Natural emission light reciprocates between the high reflection mirror 101 and the partial reflection mirror 102 , and is amplified when passing through the laser medium 103 to oscillate, and the high reflection mirror 101 and the partial reflection mirror 102 . In between, the laser beam 110 which is the wavelength of a fundamental wave is produced|generated. When the laser beam 110 is incident on the partial reflection mirror 102, a part thereof is taken out as the laser beam 3 serving as a fundamental wave. The wavelength of the light source 106 is 808 nm, 879 nm, or 888 nm, and the wavelength of the laser light 3 is 1064 nm.

The laser medium 103 is a solid-state laser medium in which a rare earth element or titanium is added to crystal, glass, or ceramics. The laser crystal constituting the laser medium 103 is YAG (Yttrium Aluminum Garnet), YVO4 (Yttrium Vanadate), GdVO4 (Gadolinium Vanadate), sapphire (Al2O3), KGW (potassium gadolinium tungsten), or KYW (potassium yttrium tungsten). to be. Rare earth elements are Nd (neodymium), Yb (ytterbium), Er (erbium), Ho (holmium), Tm (thulium), or Pr (praseodymium).

The acousto-optical element 105 receives the RF signal output by the RF driver 112, and changes the optical axis of the laser beam 110 when an RF signal is input and when an RF signal is not input. Since the laser beam 110 whose optical axis has changed by turning on the RF signal input to the acousto-optical element 105 cannot travel back and forth between the highly reflective mirror 101 and the partially reflective mirror 102, oscillation occurs. is stopped Even while oscillation is stopped, the laser medium 103 absorbs the excitation light 108 and stores energy by absorbing it. In a state in which the energy of the excitation light 108 is accumulated in the laser medium 103, the RF signal input to the acousto-optical element 105 is turned off, and the high reflection mirror 101 and the partial reflection mirror 102 are separated. By oscillating again in the meantime, the accumulated energy is emitted at once, and the laser beam 3 with high intensity|strength is output.

The pulse generator 113 controls the pulse frequency of the laser beam 3 by controlling the on and off timing of the RF signal output by the RF driver 112 . The pulse frequency of the laser beam 3 is several tens of kHz to several hundreds of kHz, and the width of the pulse is several ns to several hundreds of ns. In such a Q-switched laser, if the pulse interval time expressed as the reciprocal of the pulse frequency is shorter than the upper-level lifetime of the laser medium 103, the average output of the laser light 3 is determined by the output of the excitation light 108, When the output of the excitation light 108 is substantially constant, even if the pulse frequency of the laser light 3 changes, the change in the average output of the laser light 3 is small. That is, even if the pulsed laser light source 1 which is a Q switch laser changes a pulse frequency, it is possible to take out the laser beam 3 of a substantially constant average output.

3 is a configuration diagram of another form of a pulsed laser light source showing Example 1 of this disclosure. The pulse laser light source 200 includes a semiconductor laser 201 , a light source 205 , an optical fiber amplifier 206 , and a solid state amplifier 220 . The semiconductor laser 201 is an InGaAs semiconductor laser. The semiconductor laser 201 is pulse-driven by the driving power supply 202 to generate seed light La, which is a weak laser light. The driving power supply 202 can control the pulse frequency of the seed light La by passing a current through the semiconductor laser 201 and changing the pulse frequency of the current flowing therethrough. The pulse width of the seed light La ranges from 10ps to 100ns, and the average output is approximately proportional to the pulse frequency, from 100nW to 10mW.

The semiconductor laser 201 is coupled to the optical fiber 203 , and the seed light La propagates inside the optical fiber 203 . The coupler 204 couples the excitation light Le and the seed light La emitted from the light source 205 in the same axis and guides them to the optical fiber amplifier 206 . The optical fiber amplifier 206 absorbs the excitation light Le emitted from the light source 205, amplifies the seed light La from 10 times to 1000 times, and emits it from the end face 207 as the amplified light Lb. The optical fiber amplifier 206 is an optical fiber to which a rare earth such as Yb (ytterbium), Er (erbium), Ho (holmium), Tm (thulium), or Pr (praseodymium) is added.

The average power of the amplified light Lb is about 1 μW to 10 W. The amplified light Lb is amplified by the solid-state amplifier 220 having a solid-state laser medium, and is emitted from the solid-state amplifier 220 as the amplified light Lc. In this disclosure, the amplified light Lc becomes the laser light 3 of the fundamental wave. The solid-state amplifier 220 has a laser medium 803, an excitation light coupling mirror 804, a light source 806, and an optical fiber 807, generated from the light source 806, and emitted through the optical fiber 807 The excitation light 808 transmitted through the excitation optical system 809 and the excitation light coupling mirror 804 is absorbed by the laser medium 803 . The laser medium 803 that has absorbed the excitation light 808 saturates and amplifies the amplified light Lb. The saturated amplified amplified light Lb is reflected by the excitation light coupling mirror 804 and is emitted as the amplified light Lc. Since the solid-state amplifier 220 saturates and amplifies the amplified light Lb, the average output of the amplified light Lc is substantially constant even if the average output of the amplified light Lb varies. The average power of the amplified light Lc ranges from 1W to several hundreds of W, which is higher than the average output of the seed light La. Therefore, even if the pulse frequency of the seed light La is changed by the drive power supply 202 and the average output of the seed light La changes, the average output of the amplified light Lc does not substantially change. The light Lc can be extracted.

As shown in FIG. 1 , the laser beam 3 of the fundamental wave emitted from the pulsed laser light source 1 is condensed on the second harmonic generation crystal 5 by the condensing lens 4 . The second harmonic generating crystal 5 converts a part of the laser light 3 into a second harmonic 6 having a half wavelength of the laser light 3 . The second harmonic 6 and the laser light 3 remaining unconverted to the second harmonic 6 are condensed by a condensing lens 7 into the interior including the surface of the third harmonic generating crystal 8 . . The third harmonic generation crystal 8 generates a third harmonic 9 having a wavelength of one-third that of the laser light 3 which is the second laser light by the second harmonic 6 and the laser light 3 . make it The second harmonic generation crystal (5) and the third harmonic generation crystal (8) are LBO crystal (LiB3O5), KTP crystal (KTiPO4), BBO crystal (β-BaB2O4), CBO crystal (CsB3O5), CLBO crystal (CsLiB6O10) , etc. are non-linear media. As described above, a method of generating a laser beam having a wavelength different from that of the laser beam 3 which is a fundamental wave using a nonlinear medium is called wavelength conversion, and the nonlinear medium used at this time is called a wavelength conversion crystal. As shown in FIG. 1, the process of generating the laser beam which has a wavelength of one-third of the laser beam 3 which is a fundamental wave is called 3rd harmonic generation.

The wavenumber vectors of the laser light 3 or the second harmonic 6 incident on the third harmonic generating crystal 8 and the third harmonic 9 generated by the third harmonic generating crystal 8 are respectively k _ω , Assuming k _{2 ω} and k 3 _ω , the phase mismatch Δk in generation of the third harmonic is expressed by the following equation, and when the phase mismatch Δk becomes small, a strong third harmonic 9 is obtained.

[Number 3]

The magnitudes of the wave number vectors k _ω , k _{2 ω} , and k 3 ω are respectively expressed by the following equations using the wavelength λ of the laser beam 3 which is a fundamental wave.

[Number 4]

[Number 5]

[Number 6]

n ₁ , n ₂ , and n ₃ are the refractive indices of the third harmonic generating crystal 8 in the laser beam 3 , the second harmonic 6 , and the third harmonic 9 , respectively.

The refractive indices of the second harmonic generating crystal 5 and the third harmonic generating crystal 8 also depend on the temperature of the crystal. The temperature controller 16 and the temperature controller 17 usually make the phase mismatch Δk small and make the second harmonic generation decision 5 and the third harmonic generation decision (5) so that the average output of the third harmonic 9 is the highest. 8) to control the temperature.

The conversion efficiency of wavelength conversion depends on the peak intensity of the converted laser beam, and the conversion efficiency becomes high, so that the peak intensity of the converted laser beam is high. The laser beam 3 and the second harmonic 6, which are fundamental waves, are condensed by the condensing lens 4 or the condensing lens 7, so that the second harmonic generating crystal 5 or the third harmonic generating crystal 8 is high intensity. , and as a result, wavelength conversion with high efficiency becomes possible. Moreover, since the laser beam 3 carries out pulse oscillation, since it has a peak intensity higher than the laser beam of continuous wave oscillation which has the same average output, wavelength conversion with high efficiency becomes possible.

In order to obtain a strong third harmonic 9, the phase mismatch Δk needs to be small. Therefore, the laser beam 3 or the second harmonic 6 incident on the third harmonic generating crystal 8, and the third harmonic generating crystal The wavenumber vectors k _ω , k2ω , k _3ω of the third harmonic 9 occurring in (8) are not necessarily in the same direction. Fig. 4 is an optical path in which each laser beam travels inside a third harmonic generating crystal showing Example 1 of the present disclosure. The advancing directions of the laser beam 3, the 2nd harmonic 6, and the 3rd harmonic 9 are the directions of the _wavenumber vectors k _omega , k ₂ omega, and k 3 omega, respectively. As shown in Fig. 4, the laser beam 3 and the second harmonic 6 are incident on the third harmonic generating crystal 8 on the same axis, but in the laser beam 3 and the second harmonic 6, the wavelength or Because the polarization state is different, the inside of the third harmonic generating crystal 8 proceeds to a different refractive index. As a result, the directions of the wavenumber vectors k _omega and k ₂ omega are different inside the third harmonic generation crystal 8 .

When the phase mismatch Δk becomes the smallest, that is, when it becomes zero, Equation 3 is expressed by the following equation, and the wave number vector k _3ω of the third harmonic 9 is the wavenumber vector k _ω of the laser light 3 and the second It becomes the direction between the wavenumber vectors k _{2 ω} of the harmonics 6 .

[Number 7]

Since the laser light 3 and the second harmonic 6 are condensed inside the third harmonic generating crystal 8 by the condensing lens 7, the generated third harmonic 9 is generated by the third harmonic generating crystal 8 ), after exiting from the third harmonic generating crystal 8, the third harmonic 9 proceeds so that the diffusion angle diverges. The collimating lens 10 is a lens for making the diffusion angle of the diverging third harmonic 9 parallel, and its focal position is disposed inside including the surface of the third harmonic generating crystal 8 . . The collimating lens 10 is a plano-convex spherical or aspherical lens with rotational symmetry around an optical axis.

Alternatively, the collimating lens 10 is two plano-convex cylindrical lenses whose curvature directions are orthogonal to each other. The focal lengths of the two cylindrical lenses are different from each other, and the focal positions of the two cylindrical lenses are set to the third so that the diffusion angles of the third harmonic 9 are parallel in the respective curvature directions of the cylindrical lenses. You may arrange so that it may be located inside the surface of the harmonic generation|occurrence|production crystal 8 containing. In this case, even if the divergence angle of the third harmonic 9 emitted from the third harmonic generation crystal 8 is different in each direction of curvature of the cylindrical lens, by selecting a cylindrical lens of an appropriate focal length, The third harmonic 9 emitted from the two cylindrical lenses can be parallel to a beam shape with high roundness.

The third harmonic 9 and the laser beam 3 and the second harmonic 6 remaining without wavelength conversion in the third harmonic generating crystal 8 are separated by a wavelength separation mirror 11 . As shown in FIG. 1 , the third harmonic 9 passes through the wavelength separation mirror 11 , and the laser beam 3 and the second harmonic 6 remaining without wavelength conversion are reflected by the wavelength separation mirror 11 . . In addition, although not shown, the third harmonic 9 is reflected by the wavelength separation mirror 11 , and the laser light 3 and the second harmonic 6 remaining without wavelength conversion pass through the wavelength separation mirror 11 . also be

The laser light 3 and the second harmonic 6 remaining without wavelength conversion separated from the third harmonic 9 by the wavelength separation mirror 11 are received by the damper 12 and absorbed by the damper 12 . . In Fig. 1, the wavelength separation mirror 11 is disposed after the laser beam 3 and the second harmonic 6 remaining without wavelength conversion have passed through the collimating lens 10, but the third harmonic generation is determined You may arrange|position between (8) and the lens 10 for collimating. The wavelength separation mirror 11 is a dielectric multilayer mirror designed to have transmission characteristics at the wavelength of the third harmonic 9 and reflection characteristics at the wavelengths of the laser light 3 and the second harmonic 6 . The wavelength separation mirror 11 is not limited to the optical element of the mirror, as long as it can separate laser light according to the wavelength, or a prism or a diffraction grating whose optical axis changes depending on the wavelength may be used.

The third harmonic 9 passes through the parallel flat plate 13 and is emitted from the wavelength conversion laser device 50 . The parallel flat plate 13 has an incident surface and an exit surface of the third harmonic 9 parallel to each other, and is substantially transparent at the wavelength of the third harmonic 9 . The parallel flat plate 13 is optical glass such as synthetic quartz or BK7 to which an antireflection film for preventing reflection at the wavelength of the third harmonic 9 has been applied. The parallel flat plate 13 can control the angle in the direction of the rotational direction 15 by the angle adjusting mechanism 14, so that the angle of incidence of the third harmonic 9 to the parallel flat plate 13 can be controlled. can

The angle adjustment mechanism 14 is constituted by a rotation stage or a servo motor. When the third harmonic 9 is incident on the parallel flat plate 13 at an angle of oblique incidence excluding normal incidence, when the third harmonic 9 passes through the parallel flat plate 13 , the Since the 3rd harmonic 9 is refracted at the plane incident on the parallel flat plate 13 and the exiting plane, the optical axis of the third harmonic 9 moves in parallel before and after it is incident on the parallel plane plate 13 and after it is emitted. do.

Fig. 5 is an explanatory diagram showing the optical axis movement of the third harmonic as it passes through the parallel flat plate showing the first embodiment of the present disclosure. The third harmonic 9 is incident on the plane S1 incident on the parallel flat plate 13 at an incident angle θ ₁ , and is refracted on the incident surface S1 of the parallel flat plate 13 . Assuming that the refractive index of the parallel flat plate 13 is n and the refraction angle is θ ₂ , the refraction angle θ ₂ satisfies the following equation.

[Number 8]

In the parallel flat plate 13, since the incident surface S1 and the exit surface S2 are parallel to each other, the optical axis of the third harmonic 9 changed by refraction on the incident surface S1 is the output surface It is incident at an angle of θ ₂ with respect to (S2). If the emission angle of the third harmonic 9 emitted from the exit surface S2 is θ ₃ , the emission angle θ ₃ satisfies the following equation.

[Number 9]

As a result, θ ₁ =θ ₃ becomes, the optical axis 18 of the third harmonic 9 incident on the parallel flat plate 13 and the optical axis of the third harmonic 9 emitted from the parallel flat plate 13 . (19) becomes parallel, but the optical axis 18 and the optical axis 19 are shifted by the amount by which the third harmonic 9 is refracted inside the parallel flat plate 13. Let d be the amount of parallel movement of the optical axis 18 and the optical axis 19 of the third harmonic 9, and the distance between the surface S1 incident on the parallel flat plate 13 and the surface S2 exiting is t , then the following expression is established:

[Number 10]

Even if the pulsed laser light source 1 changes the pulse frequency by the pulse frequency control means 2, when the laser beam 3 is emitted with a substantially constant average output, if the pulse frequency of the pulsed laser light source 1 is changed, The pulse energy included in one pulse changes. As a result, since the peak intensity of the laser beam 3 changes, the conversion efficiency of wavelength conversion changes. Since increasing the pulse frequency lowers the efficiency of wavelength conversion, the average power of the third harmonic 9 is lowered. On the other hand, since the efficiency of wavelength conversion increases when the pulse frequency is reduced, the average output of the third harmonic 9 increases.

In the wavelength of the third harmonic 9, when the third harmonic generating crystal 8 has absorption, if the average output of the third harmonic 9 changes, the amount of heat absorbed by the third harmonic generating crystal 8 This changes, and as a result, the temperature of the third harmonic generating crystal 8 changes. In the nonlinear medium used for wavelength conversion, absorption of several ppm to several thousand ppm exists, and as the wavelength is shortened, the absorption ratio increases in many cases. Therefore, the ratio of absorption by the nonlinear medium of the laser beam 3 of a fundamental wave and the direction of the 3rd harmonic 9 with a shorter wavelength than the 2nd harmonic 6 tends to become high.

When the temperature of the third harmonic generating crystal 8 changes, the refractive index of the third harmonic generating crystal 8 changes, so that the phase mismatch Δk changes. As shown in Fig. 4, when the laser beam 3 and the second harmonic 6 are incident at an angle of oblique incidence excluding normal incidence with respect to the third harmonic generation crystal 8, the laser beam 3 and the second harmonic Since the refraction angle of the harmonic 6 also changes, the directions of the wavenumber vectors k _ω and k ₂ ω change. In this case, the direction of the wavenumber vector k _3ω of the third harmonic 9 is the direction in which the phase mismatch Δk is smallest.

When the pulse frequency of the pulsed laser light source 1 is changed by the pulse frequency control means 2, the direction of the optical axis of the third harmonic 9 changes according to the change in the pulse frequency. The plane in which the direction of the optical axis of the third harmonic 9 changes is the incident direction of the laser beam 3 and the second harmonic 6 to the third harmonic generating crystal 8, and the third harmonic generating crystal 8 ) is determined by the characteristics of Since the change in the direction of the optical axis of the third harmonic 9 occurs with the third harmonic generating crystal 8 as a starting point, the focal position of the collimating lens 10 is set to the surface of the third harmonic generating crystal 8 . By arranging it so that it becomes a containing interior, the direction of the optical axis of the third harmonic 9 returns to the same direction as before changing the pulse frequency. The change in the direction of the optical axis of the third harmonic 9 after passing through the third harmonic generation crystal 8 generated by changing the pulse frequency is caused by the lens 10 for collimating the third harmonic 9 ) is converted into a parallel movement of the optical axis. In the first embodiment of this disclosure, the lens 10 for collimating is composed of one optical element, and in parallel with the action of the lens for making the diverged third harmonic 9 parallel, when the pulse frequency is changed Converts the change in the direction of the optical axis of the third harmonic 9 to a parallel movement.

6 is an explanatory diagram showing the movement of the optical axis of the third harmonic after the third harmonic generation crystal passes by the lens for collimating according to the first embodiment of the present disclosure. The optical axis 9a is the optical axis of the third harmonic 9 before changing the pulse frequency, and the optical axis 9b is the optical axis of the third harmonic 9 after changing the pulse frequency. Although the directions of the optical axis 9a and the optical axis 9b after passing through the third harmonic generation crystal are different, after passing through the collimating lens 10, the optical axis 9a and the optical axis 9b move in parallel.

7 : is a measurement result of the time change of the optical axis of 3rd harmonic when the pulse frequency which shows Example 1 of this indication is changed. Although the pulse frequency of the pulsed laser light source 1 by the pulse frequency control means 2 can be switched instantaneously, the amount of parallel movement of the third harmonic 9 depends on the temperature of the third harmonic generation crystal 8 depend on The temperature change of the third harmonic generating crystal 8 depends on the thermal conductivity or heat capacity of the third harmonic generating crystal 8, and since the time constant of the temperature change is longer than the time required for changing the pulse frequency, the third harmonic generating crystal 8 A certain amount of time is required after changing the pulse frequency until the amount of parallel movement of the harmonics 9 is stabilized. As shown in FIG. 7 , after changing the pulse frequency, it takes about 30 seconds for the amount of parallel movement of the third harmonic 9 to stabilize.

The angle adjustment mechanism 14 controls the angle of the parallel flat plate 13 so as to move the optical axis in the opposite direction to the optical axis movement of the third harmonic 9 after passing through the collimating lens 10 by changing the pulse frequency. It is moved to correct the optical axis change of the third harmonic 9 after passing through the parallel flat plate 13 . Only one axis may be sufficient as the axis|shaft which angle-adjusts the angle adjustment mechanism 14. As shown in FIG.

Fig. 8 is an explanatory diagram showing correction of the optical axis change of the third harmonic by adjusting the angle of the parallel flat plate according to the first embodiment of the present disclosure. Before changing the pulse frequency, the parallel flat plate 13 is placed at the position 13a. After changing the pulse frequency, the parallel flat plate 13 is positioned at the position ( Adjust the angle to the position of 13b). In this way, the angle adjustment mechanism 14 controls so that the optical axis of the third harmonic 9 that has passed through the parallel flat plate 13 does not change before and after the change of the pulse frequency.

The angle of the parallel flat plate 13 is adjusted by the angle adjustment mechanism 14 in conjunction with the time change of the optical axis movement of the third harmonic 9 after passing through the collimating lens 10 according to the change of the pulse frequency. By controlling, it is also possible to prevent the optical axis of the third harmonic 9 passing through the parallel flat plate 13 from changing with time. The amount of optical axis movement of the third harmonic 9 after passing through the collimating lens 10 is measured in advance, and the parallel flat plate moves in the opposite direction with the same amount of optical axis movement as after changing the pulse frequency. You may control the angle adjustment mechanism 14 by determining the adjustment amount of the angle of (13). Further, a measuring instrument for measuring the position of the third harmonic 9 after passing through the parallel flat plate 13 is installed, and even if the pulse frequency is changed, the third harmonic 9 after passing through the parallel flat plate 13 is You may feedback-control the angle adjustment of the parallel flat plate 13 to the angle adjustment mechanism 14 so that a position may not change.

Fig. 9 is a diagram showing the change with time of the adjustment amount of the angle of the optical axis by the parallel flat plate after changing the pulse frequency according to the first embodiment of the present disclosure; Moreover, FIG. 10 is a calculation result of the correction amount in the case of correcting the optical-axis movement of the 3rd harmonic which occurs after passing through the collimating lens which shows Example 1 of this indication by angle adjustment of a parallel flat plate. As shown in FIGS. 9 and 10 , by adjusting the angle of the parallel flat plate 13 by the angle adjusting mechanism 14 , it becomes possible to suppress the amount of optical axis movement of the third harmonic 9 .

According to the first embodiment of the present disclosure, even when the pulse frequency of the pulsed laser light source 1 is changed by the pulse frequency control means 2, the optical axis of the third harmonic 9 is adjusted only by the single-axis angle adjustment mechanism 14. It is possible to keep it constant. In Example 1 of this indication, although generation|occurrence|production of a 3rd harmonic was demonstrated as an example, it is not limited to generation|occurrence|production of a 3rd harmonic. In addition, although the case where the parallel flat plate 13 and the angle adjustment mechanism 14 shown in Example 1 of this indication are installed in the housing in which the wavelength conversion laser device 50 is packaged was demonstrated, the wavelength conversion laser device ( 50) may be installed outside.

As described above, according to the first embodiment of this disclosure, the change in the emission angle of the third harmonic 9 due to the temperature change of the third harmonic generation crystal 8 is that the third harmonic 9 is the third harmonic generation crystal 8 . By the lens 10 for collimating after passing through (8), it is converted into the parallel movement of an optical axis. Since the optical axis of the parallel-moved third harmonic 9 is corrected by the optical axis movement by the parallel flat plate 13 whose angle is adjusted by the angle adjustment mechanism 14, the pulse frequency control means 2 uses the pulsed laser beam. Even if the pulse frequency of the light source 1 is changed, the amount of optical axis movement of the third harmonic 9 can be suppressed.

Example 2.

11 is a configuration diagram of a wavelength conversion laser device showing Example 2 of this disclosure. The wavelength conversion laser device 300 includes a reflection type wavelength separation mirror 301 that is a reflection type mirror instead of the wavelength separation mirror 11, the parallel plane plate 13, and the angle adjustment mechanism 14 shown in FIG. 1; The parallel movement mechanism 302 which is a 1st parallel movement mechanism is provided. As shown in FIG. 11 , the reflection-type wavelength separation mirror 301 reflects the third harmonic 9, which is the second laser light, by changing the direction of the optical axis by 90°, and passes the third harmonic generation crystal 8 to the wavelength The laser beam 3 and the second harmonic 6 of the fundamental wave, which are the first laser beams, which remain unconverted are transmitted. The laser light 3 and the second harmonic 6 transmitted through the reflective wavelength separation mirror 301 are received by the damper 12 and absorbed by the damper 12 . In the reflection type wavelength separation mirror 301, the optical axis of the third harmonic 9 reflected by the reflection type wavelength separation mirror 301 passes through the collimating lens 10 before and after the pulse frequency change. It is arranged so as to exist within the plane including the optical axis of the third harmonic 9 .

When the pulse frequency of the pulsed laser light source 1 is changed by the pulse frequency control means 2, the optical axis of the third harmonic 9 moves in parallel. In accordance with the parallel movement of the optical axis of the third harmonic 9, the parallel movement mechanism 302 translates the reflection type wavelength separation mirror 301 in the direction of the movement direction 303, and the movement amount and direction of the parallel movement are , the incident position of the third harmonic 9 so that the optical axis of the third harmonic 9 after passing through the collimating lens 10 caused by the change of the pulse frequency has the same movement amount and direction as the parallel movement amount control Since the direction in which the optical axis of the third harmonic 9 after passing through the collimating lens 10 moves in parallel is determined, the parallel movement mechanism 302 should just be a movement mechanism in which uniaxial parallel movement is possible.

It is explanatory drawing which shows correction|amendment of the optical axis change of the 3rd harmonic by the parallel movement of the parallel movement mechanism which shows Example 2 of this indication. As shown in Fig. 12, before changing the pulse frequency, the reflective wavelength separation mirror 301 is placed at the position 301a. After changing the pulse frequency, the position of the reflection type wavelength separation mirror 301 is moved to the position 301b by the parallel movement mechanism 302, and before and after the change of the pulse frequency, the reflection type wavelength separation mirror ( 301) does not change the optical axis of the third harmonic 9 reflected. The amount of movement of the optical axis of the third harmonic 9 after passing through the collimating lens 10 according to the change of the pulse frequency is measured in advance, and the reflective wavelength separation mirror 301 is equal to the amount of movement in conjunction with the change of the pulse frequency. ) to move it. Alternatively, a measuring instrument for measuring the position of the optical axis of the third harmonic 9 reflected from the reflection type wavelength separation mirror 301 is provided, and the third harmonic wave reflected from the reflection type wavelength separation mirror 301 even if the pulse frequency is changed In (9), the position of the reflection type wavelength separation mirror 301 may be feedback-controlled through the parallel movement mechanism 302 so that the position of the optical axis does not change.

Thus, according to Example 2 of this indication, even if it changes a pulse frequency, only the uniaxial translation mechanism 302 can maintain the position of the optical axis of the 3rd harmonic 9 emitted constant. In addition, the wavelength separation of the laser light 3 and the second harmonic 6 and the third harmonic 9 and the correction of the optical axis movement of the emitted third harmonic 9 are performed by one reflective wavelength separation mirror 301 . is made possible with

Example 3.

13 is a configuration diagram of a wavelength conversion laser device showing Example 3 of this disclosure. The wavelength conversion laser device 400 includes a prism 401 as a first prism, a prism 402 as a second prism, 2 The parallel movement mechanism 403 which is a parallel movement mechanism is provided.

Even if the laser beam 3 and the second harmonic 6 of the fundamental wave, which is the first laser beam, are circular laser beams in the third harmonic generation crystal 8, when the wavelength is converted by the third harmonic generation crystal 8 , the allowable angle formed by the wavenumber vectors of the laser beam 3 and the second harmonic 6 and the third harmonic 9 varies depending on the direction. As a result, the 3rd harmonic 9 which is the 2nd laser beam which generate|occur|produces from the 3rd harmonic generation crystal|crystallization 8 differs according to the traveling direction, and becomes an elliptical laser beam. Since the laser light 3 and the second harmonic 6 are focused on the third harmonic generating crystal 8 by the condensing lens 7 , the third harmonic 9 generated from the third harmonic generating crystal 8 is In each traveling direction, the position of the beam waist of the third harmonic 9 is at the position of the third harmonic generation crystal 8, and the collimating lens 10 takes the third harmonic 9 in the shape of an ellipse. While maintaining it, make it parallel in each advancing direction.

As shown in FIG. 13, the 3rd harmonic 9 parallelized by the lens 10 for collimating passes through the prism 401 and the prism 402 which are triangular-prism shape. The prism 401 and the prism 402 are adjusted to change only the beam diameter in one direction of the third harmonic 9 to be the same as the beam diameter in the other direction of the third harmonic 9, and the prism 401 ) and the prism 402, the third harmonic 9 incident in the shape of an ellipse is converted into a circular shape. When the beam diameter in the changing direction by the prisms 401 and 402 is smaller than the beam diameter in another direction, the prism 401 and the prism 402 enlarge the beam diameter in the changing direction.

Fig. 14 is an explanatory diagram showing a state in which a beam diameter is enlarged by a prism according to a third embodiment of the present disclosure. The laser light 405 incident on the prism 401 is refracted when passing through the prism 401 and the prism 402 , the beam diameter is enlarged, and is emitted as the enlarged laser light 406 . The magnification of the beam diameter depends on the refractive index and incidence angle of the prism 401 and the prism 402 , and does not depend on the distance between the prisms 401 and the prism 402 .

As shown in FIG. 13 , when the pulse frequency of the pulsed laser light source 1 is changed by the pulse frequency control means 2 , the parallel movement mechanism 403 moves the prism 402 in parallel in the direction of the movement direction 404 . make it The moving direction 404 is a direction parallel to the optical axis of the third harmonic 9 emitted from the prism 402 . The translation mechanism 403 controls the amount of movement of the prism 402 so that the optical axis of the third harmonic 9 after passing through the collimating lens 10 compensates for the amount of translation in the third harmonic 9. control the incident position of Since the direction in which the optical axis of the third harmonic 9 after passing through the collimating lens 10 moves in parallel is determined, the parallel movement mechanism 403 may be a movement mechanism capable of parallel movement in one direction.

It is explanatory drawing which shows the correction|amendment of the optical axis change of the 3rd harmonic by the parallel movement of the parallel movement mechanism which shows Example 3 of this indication. Prior to changing the pulse frequency, the prism 402 is placed at the position of position 402a. By controlling the prism 402 to the position of the position 402b by the parallel movement mechanism 403 in conjunction with the change of the pulse frequency, before and after the change of the pulse frequency, the third harmonic that has passed through the prism 402 Make sure that the optical axis of (9) does not change. The amount of movement of the optical axis of the third harmonic 9 after passing through the collimating lens 10 according to the change of the pulse frequency is measured in advance, and the optical axis of the third harmonic 9 after passing through the prism 402 is measured. It is enough to calculate the position of the prism 402 whose position does not change. Alternatively, a measuring instrument for measuring the position of the optical axis of the third harmonic 9 after passing through the prism 402 is provided, and even if the pulse frequency is changed, the optical axis of the third harmonic 9 after passing through the prism 402 is changed. You may feedback-control the position of the prism 402 through the parallel movement mechanism 403 so that a position may not change.

As described above, according to the third embodiment of the present disclosure, even if the pulse frequency is changed, the position of the optical axis of the emitted third harmonic 9 can be kept constant only by the parallel movement mechanism 403 in one direction. In addition, it becomes possible to separate the wavelength of the laser beam 3, the second harmonic 6 and the third harmonic 9, and to convert the beam shape of the emitted third harmonic 9 from an elliptical to a circular shape.

Example 4.

Fig. 16 is a configuration diagram of a wavelength conversion laser processing machine showing a fourth embodiment of this disclosure. As shown in FIG. 16 , the wavelength conversion laser processing machine 500 includes a wavelength conversion laser apparatus 501 that is any of the wavelength conversion laser apparatuses according to Examples 1 to 3 of this disclosure, and an object 509 to be processed. and a workpiece support part 508 for supporting the . The wavelength conversion laser processing machine 500 includes a mask 504 and a processing head 505 for irradiating a laser beam 502, which is a second laser beam emitted from the wavelength conversion laser device 501, onto the object 509; A relative movement unit 512 for relatively moving the processing head 505 and the object support unit 508 , and a control unit 513 for controlling the operations of the relative movement unit 512 and the wavelength conversion laser device 501 . to provide

The object support 508 supports the object 509 on which the object 509 is mounted. In Example 4 of this indication, the to-be-processed object 509 is a flexible printed circuit board (FPC:Flexible Printed Circuits) or a printed wiring board (PCB:Printed Circuit Board) multilayered multilayer board|substrate. A flexible printed circuit board and a printed wiring board are comprised from resin and copper. For this reason, it is preferable that the wavelength of the laser beam 502 emitted from the wavelength conversion laser device 501 shown in Example 4 of this indication is the ultraviolet region absorbed by both resin and copper.

The processing head 505 includes a light guide mirror 506 and a condensing lens 507 . The laser beam 502 emitted from the wavelength conversion laser device 501 is incident on the mask 504 with a beam diameter and divergence angle adjusted by the beam adjustment optical system 503 . The mask 504 has a circular or rectangular opening, and the shape of the laser beam 502 after passing through the mask 504 is the same as the shape of the opening of the mask 504 . The laser light 502 that has passed through the mask 504 passes through the light guide mirror 506 and the condensing lens 507 , and is irradiated to the object 509 . The condensing lens 507 transfers the shape of the laser beam 502 at the position after passing through the mask 504 to the object 509 to be processed.

The relative movement unit 512 relatively moves the laser beam 502 irradiated from the processing head 505 and the object support unit 508 along at least one of the X direction and the Y direction shown in FIG. 16 . In the fourth embodiment of this disclosure, the relative movement unit 512 moves the object support unit 508 along at least one of the X direction and the Y direction, but moves the machining head 505 in both the X direction and the Y direction. may be moved, or both the machining head 505 and the object support 508 may be moved along at least one of the X-direction and the Y-direction.

The relative movement unit 512 includes a motor, a lead screw for moving the object support unit 508 by the rotational driving force of the motor, and a linear guide for guiding the moving direction of the object support unit 508 . The configuration of the relative moving unit 512 is not limited to a configuration of a motor, a lead screw, and a linear guide. The relative movement unit 512 is controlled by a control device 513 . Moreover, the relative moving part 512 may be equipped with a galvanometer mirror or a polygon mirror, and may scan the laser beam 502 by a galvanometer mirror or a polygon mirror. In this case, the condensing lens 507 is preferably constituted by an Fθ lens.

The wavelength conversion laser processing machine 500 shown in Example 4 of this indication receives the laser beam 502 passing through the processing head 505 while moving the to-be-processed object support part 508 by the relative moving part 512. By irradiating, the laser beam 502 is scanned from the surface of the object 509 to be processed. The wavelength conversion laser processing machine 500 forms a fine processing hole 510 at a predetermined desired position in the object 509 to be processed. The machining hole 510 is a stop hole or a through hole. The diameter of the processing hole 510 can be suitably set according to the diameter of the opening of the mask 504. When the wavelength conversion laser device 501 is driven with a specific pulse frequency, the central position of the opening of the mask 504 is adjusted to coincide with the optical axis of the laser light 502 .

The pulse energy of the laser light 502 required for processing varies depending on the depth and shape of the processing hole 510 formed in the processing target 509 and the difference in the constituent materials of the processing target 509 . do. When the wavelength conversion laser device 501 is driven with a high pulse frequency, the pulse energy of the laser light 502 becomes low, and when the wavelength conversion laser device 501 is driven with a low pulse frequency, the pulse energy becomes high. On the other hand, if it is the laser beam 502 which has the pulse energy required for processing, high-speed processing becomes possible, so that a pulse frequency is high. Therefore, when high-speed machining is performed after securing the pulse energy required for machining, it is preferable to adjust the pulse frequency for each kind of machining.

Since the wavelength conversion laser processing machine 500 shown in Example 4 of this indication is equipped with any of the wavelength conversion laser apparatuses concerning Example 1 to Example 3 of this indication, the wavelength conversion laser device 501 according to the type of processing. ), the optical axis of the laser beam 502 does not change even if the driving pulse frequency is changed. Therefore, even if the pulse frequency of the wavelength conversion laser device 501 changes, the shape of the laser beam 502 after passing through the mask 504 does not change, and the laser beam ( 502) does not change either.

17 : is intensity distribution of the laser beam just before passing through the mask which shows Example 4 of this indication. 18 is an intensity distribution of laser light after passing through the mask before changing the pulse frequency for driving the wavelength conversion laser device showing Example 4 of this disclosure. Before changing the pulse frequency for driving the wavelength conversion laser device 501, the central position of the mask 504 is adjusted so that the central position of the opening of the mask 504 and the optical axis of the laser beam 502 coincide. . 19 is an intensity distribution of a laser beam when the optical axis of the laser beam after passing through the mask showing Example 4 of this indication shifts from the center position of the mask. In the conventional wavelength conversion laser processing machine, since the optical axis of the laser beam 502 shifts as shown in FIG. 19 by changing the pulse frequency which drives the wavelength conversion laser device 501, the mask 504 is shifted only by the optical axis shift. ), the intensity distribution of the laser beam 502 after passing through it changes. Since this changed intensity distribution is transferred to the object 509 to be processed, the currently assumed processing cannot be performed, resulting in processing failure.

20 is an intensity distribution of the laser beam of the laser beam 502 after passing through the mask after changing the pulse frequency for driving the wavelength conversion laser device according to Example 4 of this disclosure. As shown in FIGS. 18 and 20 , even if the pulse frequency for driving the wavelength conversion laser device 501 is changed, the optical axis of the laser beam 502 does not shift, so the laser beam 502 after passing through the mask 504 . The intensity distribution of the wavelength conversion laser device 501 has the same shape as the intensity distribution of the laser beam 502 after passing through the mask 504 before changing the pulse frequency for driving the wavelength conversion laser device 501 becomes Therefore, the wavelength conversion laser processing machine 500 which shows Example 4 of this indication becomes high-speed and high-quality processing of the to-be-processed object 509 is attained.

1, 200: pulsed laser light source 2: pulse frequency control means
3, 110, 405, 406, 502: laser light 4, 7, 507: condensing lens
5: 2nd harmonic generation decision 6: 2nd harmonic
8: 3rd harmonic generation decision 9: 3rd harmonic
10: Collimating lens 11: Wavelength separation mirror
12: damper 13: parallel flat plate
13a, 13b, 301a, 301b, 402a, 402b: position
14: angle adjustment mechanism 15: rotation direction
16,17: temperature controller 9a, 9b, 18, 19: optical axis
50, 300, 400, 501: wavelength conversion laser device
101: highly reflective mirror 102: partially reflective mirror
103, 803: laser medium 104, 804: excitation light coupling mirror
105: acoustooptical element 106, 205, 806: light source
107, 203, 807: optical fiber 108, 808: excitation light
109, 809: excitation optical system 112: RF driver
113: pulse generator 201: semiconductor laser
202: driving power 204: combiner
206: optical fiber amplifier 207: single-sided
220: solid-state amplifier 301: reflective wavelength separation mirror
302, 403: translation mechanism 303, 404: movement direction
401, 402: prism 500: wavelength conversion laser processing machine
503: beam adjustment optical system 504: mask
505: machining head 506: light guide mirror
508: object support part to be processed 509: object to be processed
510: machining hole 511: stage scanning direction
512: relative moving unit 513: control device

Claims (13)

A pulse laser light source for generating a first laser light;
a pulse frequency control means for controlling the pulse frequency of the first laser light pulsed by the pulsed laser light source;
a non-linear medium for wavelength-converting a portion of the first laser light into a second laser light;
a condensing lens for condensing the first laser light;
A collimating lens for adjusting the diffusion angle of the second laser light;
The second laser light passing through the collimating lens is incident, and a parallel flat plate that is transmitted and emitted;
and an angle adjustment mechanism for controlling an incident angle of the second laser beam incident on the parallel flat plate. The method according to claim 1,
and the angle adjustment mechanism controls the angle of incidence of the second laser light incident on the parallel flat plate so as to keep the optical axis of the second laser light emitted from the parallel flat plate constant. 3. The method according to claim 2,
The wavelength conversion laser device according to claim 1, wherein the angle adjustment mechanism is controlled in conjunction with the change of the pulse frequency by the pulse frequency control means. 4. The method according to claim 3,
The wavelength conversion laser device, characterized in that the first laser light is incident at an angle of oblique incidence with respect to the nonlinear medium. A pulse laser light source for generating a first laser light;
a pulse frequency control means for controlling the pulse frequency of the first laser light pulsed by the pulsed laser light source;
a non-linear medium for wavelength-converting a portion of the first laser light into a second laser light;
a condensing lens for condensing the first laser light;
A collimating lens for adjusting the diffusion angle of the second laser light;
and a reflective mirror that reflects and emits the second laser light passing through the collimating lens as well as incident;
and a first parallel movement mechanism for controlling an incident position of the second laser light incident on the reflective mirror. 6. The method of claim 5,
The first parallel movement mechanism controls the incident position of the second laser light incident on the reflective mirror so as to keep the optical axis of the second laser light reflected from the reflective mirror constant. Device. 7. The method of claim 6,
The wavelength conversion laser device according to claim 1, wherein the first parallel movement mechanism is controlled in conjunction with the change of the pulse frequency by the pulse frequency control means. 8. The method of claim 7,
The wavelength conversion laser device, characterized in that the first laser light is incident at an angle of oblique incidence with respect to the nonlinear medium. A pulse laser light source for generating a first laser light;
a pulse frequency control means for controlling the pulse frequency of the first laser light pulsed by the pulsed laser light source;
a non-linear medium for wavelength-converting a portion of the first laser light into a second laser light;
a condensing lens for condensing the first laser light;
A collimating lens for adjusting the diffusion angle of the second laser light;
The second laser light passing through the collimating lens is incident, and a first prism that is transmitted and emitted;
and a second prism that passes through the first prism and enters the second laser light, and is transmitted and emitted;
and a second parallel movement mechanism for controlling an incident position of the second laser beam incident on the second prism. 10. The method of claim 9,
The second parallel movement mechanism controls the incident position of the second laser light incident on the second prism so as to keep the optical axis of the second laser light emitted from the second prism constant. Device. 11. The method of claim 10,
and the second parallel movement mechanism is controlled in conjunction with the change of the pulse frequency by the pulse frequency control means. 12. The method of claim 11,
The wavelength conversion laser device, characterized in that the first laser light is incident at an angle of oblique incidence with respect to the nonlinear medium. The wavelength conversion laser device according to any one of claims 1 to 12;
an object support part for supporting the object to be processed;
a mask having an opening and allowing a part of the second laser light emitted from the wavelength conversion laser device to pass through the opening;
a processing head that irradiates the second laser beam that has passed through the mask to the object to be processed;
A wavelength conversion laser processing machine having a relative moving part for relatively moving the second laser beam irradiated from the processing head and the target object support part.

Images