JP2012141515A - Fluid optical element, laser light source device and laser processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain desired optical property by using temperature dependency of a refractive index of a medium.SOLUTION: A fluid optical element 10 includes a container 11 having edge surfaces 11A and 11B which transmit incident light and are opposite each other to store fluid 12 which is a medium having temperature dependency of a refractive index and wavelength selectivity to absorb first laser light L1 of a first wave length λ1 and to transmit second laser light L2 of a second wave length λ2. An opening 14 for incoming light or outgoing light is provided at least on the edge surface at a side where densely converged light transmits. The fluid optical element 10 provides the incident second laser light L2 of the second wave length λ2 with a lens effect by generating: a temperature gradient in the fluid 12 through irradiating the same with the first laser light L1 of the first wave length λ1; and a lens effect due to a refractive index gradient in the fluid 12 associated with the temperature gradient or a thermal lens effect.

Description

  The present invention relates to a fluid optical element that exhibits a desired optical characteristic by utilizing temperature dependency of a refractive index of a medium, a laser light source device including the fluid optical element, and a laser processing apparatus.

  A laser processing apparatus uses a laser beam as a heat source, locally heats an object to be processed by the heat of the beam, and performs laser processing such as drilling, welding, and heat treatment.

  Since a carbon dioxide laser, a YAG laser, and the like have strong power, a hole can be drilled or welded by applying a beam to an object to be processed. If the beam power is reduced, it can also be used for heat treatment. As far as drilling is concerned, it can be said that productivity is high because a large number of holes can be drilled in a shorter time than drilling with a mechanical drill.

  A mirror or lens is required to guide the laser beam to the target. Since the carbon dioxide laser has a wavelength of 9 μm to 11 μm and is infrared light, it is condensed by using a ZnSe lens or the like that can transmit it. Since the YAG laser is 1.06 μm, a lens made of a normal glass material may be used.

  Speaking of laser emission, there are a case where light is emitted continuously and a case where light is emitted in pulses. Depending on the purpose, continuous light and pulsed light can be used properly. In many cases, laser processing is performed by generating pulsed light having a large energy by the Q switch.

  Conventionally, in a laser processing apparatus that uses a laser beam as a heat source, the spatial power distribution of the laser beam affects the processing accuracy and so on. The distribution is converted into a top hat type having a constant power within a certain range from the basic type (normal distribution), and the workpiece is irradiated with a top hat type laser beam (see, for example, Patent Document 1).

JP 2003-114400 A

  However, as described above, the input beam profile intensity distribution is converted from the basic type (normal distribution) to a top hat type top hat type having a constant power in a certain range by an optical system including a diffractive optical element and an individual lens. In a conventional laser processing apparatus in which a workpiece is irradiated with a top-hat type laser beam, the solid lens has a fixed focal point and may be damaged by a very strong laser beam. That is, an optical element such as a lens is used in various situations, but generally has a problem that a parameter such as a focal length is fixed and is damaged by incidence of light of very strong intensity. Further, since the conversion of the input beam profile intensity distribution from the basic type (normal distribution) to the top hat type is complicated, the input beam intensity is limited and the apparatus cost is increased.

  Accordingly, an object of the present invention is to provide a desired optical characteristic using the temperature dependence of the refractive index of the medium, and a fluid optical element that is less likely to be damaged by the incidence of intense light, It is an object of the present invention to provide a laser light source apparatus and a laser processing apparatus that are capable of emitting laser light having a desired beam profile intensity distribution by including the fluid optical element.

  Other objects of the present invention and specific advantages obtained by the present invention will become more apparent from the description of embodiments described below.

  When light is applied to a substance, most of the light is converted into heat and heat is released. The material undergoes a refractive index change due to heat. When light having an intensity distribution such as condensed laser light is applied, the substance has the same effect as the lens. This is called the thermal lens effect.

  In general, since the refractive index of a fluid changes with temperature and intensity of irradiated laser light, a refractive index distribution is generated in a fluid having these distributions.

When another laser beam is irradiated here, the beam profile (the shape of the beam when the laser beam is projected on a screen or the like, that is, the light intensity in the x and y directions when the laser beam traveling direction is the z axis [W / m ² ] distribution) shows a characteristic change in the refractive index distribution before and after passing through the fluid. Accordingly, top hat processing, concave lenses, and the like can be formed in combination with the formation of an appropriate refractive index distribution.

  That is, in the present invention, desired optical characteristics are obtained by utilizing the temperature dependence of the refractive index of the medium.

  The present invention is a fluid optical element, and is provided with an entrance or exit opening on an end face on the side where at least high-density converged light passes through mutually facing end faces through which incident light passes. The container is a medium having a temperature dependency on the refractive index, and contains a liquid having wavelength selectivity that absorbs the laser light of the first wavelength and transmits the laser light of the second wavelength, and A temperature gradient is given to the liquid by the irradiation of the laser beam of the first wavelength, and a lens effect due to the refractive index gradient of the liquid accompanying the temperature gradient is exhibited. A lens effect is imparted.

  In the fluid optical element according to the present invention, the liquid may contain a dye that absorbs the laser beam having the first wavelength.

  In addition, the fluid optical element according to the present invention can impart the lens effect according to the light amount profile of the laser light having the first wavelength to the laser light having the second wavelength.

  In the fluid optical element according to the present invention, the laser light having the first wavelength may be irradiated in a state where an intensity distribution is given via a beam shaper.

  Further, in the fluid optical element according to the present invention, the beam shaper provides an intensity distribution that imparts the lens effect of emitting the incident second wavelength laser beam as a top hat beam to the second wavelength laser beam. Can be provided to the laser light of the first wavelength.

  The present invention is a laser light source device, in which a first laser light source that emits laser light of a first wavelength, a second laser light source that emits laser light of a second wavelength, and incident light A medium having a temperature dependency on a refractive index in a container provided with an entrance or exit opening on an end face on a side through which at least high-density focused light passes through mutually facing end faces. The first wavelength laser light is absorbed and the second wavelength laser light is transmitted through a liquid having wavelength selectivity. The temperature gradient of the liquid is caused by the irradiation of the first wavelength laser light. A fluidic optical element, which exhibits a lens effect due to a refractive index gradient of the liquid with the temperature gradient and imparts the lens effect to the incident laser light of the second wavelength. , Given the above lens effect Characterized by emitting a laser beam having a second wavelength.

  In the laser light source device according to the present invention, the liquid may contain a dye that absorbs the laser light having the first wavelength.

  The laser light source device according to the present invention may impart the lens effect according to the light amount profile of the laser light having the first wavelength to the laser light having the second wavelength.

  The laser light source device according to the present invention further includes a beam shaper that gives an intensity distribution to the laser beam having the first wavelength, and the fluid optical element is configured such that the laser beam having the first wavelength passes through the beam shaper. The liquid may be irradiated with an intensity distribution given.

  Furthermore, in the laser light source device according to the present invention, the beam shaper converts the incident laser light having the second wavelength into a top hat beam and emits the lens effect from the fluid optical element to the laser light having the second wavelength. The intensity distribution to be applied can be given to the laser beam having the first wavelength.

  The present invention is a laser processing apparatus, wherein a first laser light source that emits laser light of a first wavelength, a second laser light source that emits laser light of a second wavelength, and incident light A medium having a temperature dependency on a refractive index in a container provided with an entrance or exit opening on an end face on a side through which at least high-density focused light passes through mutually facing end faces. The first wavelength laser light is absorbed and the second wavelength laser light is transmitted through a liquid having wavelength selectivity. The temperature gradient of the liquid is caused by the irradiation of the first wavelength laser light. A fluid optical element that exhibits a lens effect due to a refractive index gradient of the liquid with the temperature gradient and imparts the lens effect to the incident laser light having the second wavelength; and the incident second optical element Top hat laser with wavelength A beam shaper that gives the laser light of the first wavelength a distribution of intensity that gives the laser light of the second wavelength the lens effect emitted from the fluid optical element, and the lens effect is achieved by the fluid optical element. A laser light source device that emits laser light of the second wavelength as a top hat beam from the opening, a table on which a workpiece is placed, and the second light emitted from the opening of the laser light source device. Drive means for relatively moving the workpiece placed on the table irradiated with the laser beam with the second wavelength and the laser beam with the second wavelength.

  In the laser light source device according to the present invention, the liquid may include a dye that absorbs the laser light having the first wavelength.

  Furthermore, in the laser light source device according to the present invention, the second laser light source may output a pulsed laser beam as the laser light having the second wavelength.

  In the present invention, the liquid stored in the container of the fluid optical element is given a temperature gradient by irradiation with the laser beam of the first wavelength, thereby exhibiting a lens effect due to the refractive index gradient of the liquid accompanying the temperature gradient, and entering the liquid. The above-mentioned lens effect can be imparted to the laser light of the second wavelength, and desired optical characteristics such as top hat processing, concave lens and convex lens can be formed in combination with the formation of an appropriate refractive index distribution. Can do.

  In the present invention, the liquid contained in a container provided with an entrance or exit opening on an end surface on the side where light condensed at least with high density of end surfaces facing each other through which incident light passes is provided. This is a medium having a temperature dependency on the refractive index, and has a wavelength selectivity that absorbs the laser beam of the first wavelength and transmits the laser beam of the second wavelength. When a temperature gradient is given by irradiation of light, a lens effect due to the refractive index gradient of the liquid accompanying the temperature gradient is exhibited, and the laser beam having the first wavelength with respect to the incident second wavelength laser beam. According to the present invention, desired optical characteristics such as top-hat processing and concave lenses can be formed in combination with the formation of an appropriate refractive index distribution. It is possible.

  In the present invention, the liquid contains a dye that absorbs the laser beam having the first wavelength, thereby absorbing the laser beam having the first wavelength and transmitting the laser beam having the second wavelength. It is possible to significantly exhibit wavelength selectivity.

  In the present invention, the light amount profile of the laser beam having the first wavelength can be arbitrarily set by a beam shaper. For example, the beam shaper can convert the incident laser beam having the second wavelength into a top hat beam. As described above, the intensity distribution that gives the lens effect emitted to the second wavelength laser beam can be given to the first wavelength laser beam.

  Furthermore, in the present invention, by providing an opening at the end surface through which the focused light of the container containing the liquid passes, there is little possibility that the fluid optical element is damaged by the incidence of strong light.

  For example, a collimator that produces parallel light by changing only the beam system (the diameter of the laser light in a direction perpendicular to the traveling direction of the laser light) without condensing and expanding the laser light with a pair of optical lenses, reduces the beam system. In this case, since the beam collected by the preceding optical lens is incident on the latter optical lens, there was a great restriction on the intensity of the original laser beam in order to prevent damage to this, but the latter optical lens As described above, by using the fluid optical element according to the present invention, it is possible to realize a laser processing apparatus capable of processing micro holes with a very large aspect ratio of several hundred nm to several hundred mm.

  That is, according to the present invention, fluid optics that can exhibit desired optical characteristics by the thermal lens effect utilizing the temperature dependence of the refractive index of the medium, and that is less likely to be damaged by the incidence of intense light. By providing the element and the fluid optical element, it is possible to provide a laser light source apparatus and a laser processing apparatus that can emit laser light having a desired beam profile intensity distribution.

It is a principal part longitudinal cross-sectional view which shows typically the structural example of the fluid optical element to which this invention is applied. It is a principal part longitudinal cross-sectional view which shows the analysis model of the said fluid optical element. It is a figure which shows the result of having performed temperature distribution analysis about the analysis model of the said fluid optical element. It is a principal part longitudinal cross-sectional view which shows the detection light propagation model by the ray-tracing method when detection light injects into the said fluid optical element. It is a block diagram which shows the structural example of the laser light source device using the fluid optical element to which this invention is applied. It is a figure which shows the light intensity change model of the detection light used for calculation of the spatial light intensity distribution of detection light about the fluid optical element in the said laser light source apparatus. It is a figure which shows the result of having calculated the spatial light intensity distribution of the detection light radiate | emitted from the fluid optical element in the said laser light source device with the light intensity change model of the said detection light, and the result measured by the imaging device. In the laser light source device, the first light emitted through the fluid optical element when the power of the laser light having the first wavelength is changed and when the distance from the fluid optical element to the imaging device is changed. It is a figure which shows the change of the light intensity distribution of the laser beam of 2 wavelength. In the said laser light source apparatus, it is a figure which shows the top hat profile obtained as light intensity distribution of the laser beam of the 2nd wavelength radiate | emitted from a fluid optical element. In the said laser light source device, it is a figure which shows the prediction result obtained by calculating the distance from the fluid optical element from which a top hat profile is obtained to an imaging device. In the said laser light source device, it is a figure which shows the mode of a detection light profile at the time of changing a distance from a fluid optical element to an imaging device, and a beam diameter. It is a principal part longitudinal cross-sectional view which shows typically the structural example of a collimator using the said fluid optical element. It is a block diagram which shows the structural example of the laser processing apparatus using the laser light source apparatus to which this invention is applied.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Needless to say, the present invention is not limited to the following examples, and can be arbitrarily changed without departing from the gist of the present invention.

  The fluid optical element 10 according to the present invention exhibits a desired optical characteristic by a thermal lens effect using the temperature dependence of the refractive index of a medium. For example, as shown in FIG. The container 11 having the end faces 11A and 11B that pass through each other is a medium having a temperature dependency on the refractive index, and the laser beam L1 having the first wavelength λ1 is absorbed, and the laser beam L2 having the second wavelength λ2 is absorbed. Contains a liquid 12 having a wavelength selectivity to transmit, and is provided with an entrance or exit opening 14 on an end face on the side where light condensed at a high density passes.

  In the fluid optical element 10, a temperature gradient is given to the liquid 12 by irradiation with the laser light L1 having the first wavelength λ1, and a lens effect due to a refractive index gradient of the liquid 12 accompanying the temperature gradient, that is, a thermal lens effect. The lens effect is imparted to the incident laser beam L2 having the second wavelength λ2.

Here, as the container 11, for example, a cuvette in which both end openings of a copper ring 11C having an inner diameter of 30 mm, a wall thickness of 10 mm, and a height of 1 mm are closed by quartz glass end faces 11A and 11B is used. Contains 0.05 g / l of set yellow dye (6-hydroxy-5-[(4-sulfonatophenyl) diazenyl] naphthalene-2-sulfonic acid disodium (C ₁₆ H ₁₀ N ₂ Na ₂ O ₇ S ₂ )) As a result of analyzing the temperature characteristics of the sample of the fluid optical element 10 in which the ethanol to be stored in the container 11 was analyzed, the following results were obtained.

  That is, the thermal conductivity [W / (m · K)] is copper = 380, ethanol = 0.15, quartz = 1.4, and the laser light L1 having the first wavelength λ1 (wavelength λ1 = 473 nm, power P = The analysis model shown in FIG. 2 irradiated with 10 mW and beam diameter W = 0.25 mm) as excitation light is the result of performing the temperature distribution analysis of the region surrounded by the broken line according to the following rule form (A) in FIG. , (B), (C).

3A shows the calculation result of the temperature distribution in the sample, and FIG. 3B shows the calculation result of the temperature distribution in the r-axis direction, that is, the radial direction in the sample. ) shows the state of refraction due to the change in refractive index alpha _r, which is proportional to the temperature gradient dT / dr represented by the temperature distribution in the r-axis direction indicated by the FIG 3 (B) schematically.

  When the laser light L2 having the second wavelength λ2 is incident as the detection light on the sample subjected to the temperature distribution analysis, a detection light propagation model by the ray tracing method is as shown in FIG.

  In this propagation model, the ray trajectory is obtained from the refractive index n (T) at the temperature T expressed by the following calculation formula.

Further, the change of the phase φ _i is obtained by the following calculation formula.

  The fluid optical element 10 can exhibit a desired optical characteristic by the thermal lens effect using the temperature dependence of the refractive index of the liquid 12, and for example, as shown in FIG. The laser light source device 1 that can arbitrarily set the light amount profile of the laser light L2 can be configured.

  The laser light source device 1 includes a first laser light source 2 that emits laser light having a first wavelength λ1 (wavelength λ1 = 473 nm, power P = 10 mW, beam diameter φ = 0.7 mm) L1, and Gaussian distribution light. A second laser light source 3 that emits laser light having a second wavelength λ2 having an intensity distribution (wavelength λ2 = 1064 nm, beam diameter φ = 1.0 mm) L2, a beam shaper 4, a reflecting mirror 5, and a semi-transparent mirror 6 and a fluid optical element 10.

  In the laser light source device 1, the semi-transparent mirror 6 reflects the laser light L 1 having the first wavelength λ 1 emitted from the first laser light source 2 and reflects the second light emitted from the second laser light source 3. The laser light L2 having the wavelength λ2 has a wavelength selectivity for transmission. Then, the laser light L1 having the first wavelength λ1 emitted from the first laser light source 2 is reflected by the semi-transparent mirror 6 and enters the fluid optical element 10 as excitation light. The laser light L2 having the second wavelength λ2 emitted from the second laser light source 3 is reflected by the reflecting mirror 5, passes through the semi-transparent mirror 6, and enters the fluid optical element 10 as detection light. Is done.

  Here, the spatial light intensity distribution I ′ (r) of the detection light for the fluid optical element 10 of the sample in the laser light source device 1 having such a configuration was calculated using the light intensity change model of the detection light shown in FIG. FIGS. 7A and 7B show the results and results obtained by actually measuring the spatial light intensity distribution I ′ (r) of the detection light by the imaging device 50 using the CCD image sensor.

  Here, the spatial light intensity distribution I ′ (r) of the detection light in the light intensity change model of the detection light was obtained by the following calculation formula.

  In the laser light source device 1, the light intensity distribution of the laser light L2 having the second wavelength emitted through the fluid optical element 10 of the sample is the laser light L1 having the first wavelength, that is, the power P of the excitation light. For example, as shown in FIG. 8A, the distance d from the fluid optical element 10 of the sample to the imaging device 50 is changed, for example, as shown in FIG. To change.

  That is, the fluid optical element 10 is given a temperature gradient according to the light amount profile of the laser light L1 having the first wavelength, and a lens effect by the refractive index gradient of the liquid accompanying the temperature gradient, that is, a thermal lens effect. Therefore, in the laser light source device 1, by changing the light amount profile of the laser beam L1 having the first wavelength λ1, the first wavelength is changed with respect to the incident laser beam L2 having the second wavelength λ2. An arbitrary lens effect according to the light amount profile of the laser light L1 of λ1 can be given.

  For example, the light intensity profile of the laser light L1 having the first wavelength λ1 is changed by using, as the first laser light source 2, a semiconductor laser capable of changing the laser power by adjusting the drive current flowing through the laser diode. be able to.

  Further, by giving a desired intensity distribution to the laser light L1 having the first wavelength λ1 emitted from the first laser light source 2 by the beam shaper 4, the light intensity profile of the laser light L1 having the first wavelength λ1 can be obtained. It can also be changed. The light amount profile of the laser beam L1 having the first wavelength λ1 can be arbitrarily changed by the beam shaper 4. For example, the lens effect of emitting the incident laser beam L2 having the second wavelength λ2 as a top hat beam. Can be applied to the laser beam L1 having the first wavelength λ1 by the beam shaper 4.

  In the laser light source device 1, the light intensity distribution of the detection light emitted through the fluid optical element 10 of the sample, that is, the laser light L2 having the second wavelength λ2, is measured by the imaging device 50 using a CCD image sensor. Then, as shown in FIG. 9, when the distance from the fluid optical element 10 of the sample to the imaging device 50 is 180 mm, the light of the laser light L2 having the second wavelength λ2 emitted from the fluid optical element 10 is obtained. A top hat profile was obtained as the intensity distribution.

When the distance from the fluid optical element 10 to the imaging device 50 is 180 mm, the prediction results obtained by calculation with the absorption coefficient of 1.2 cm ⁻¹ coincided.

Here, in the case where the laser light of the first wavelength (wavelength λ1 = 473 nm beam diameter φ = 0.5 mm) is used as the excitation light and the power P of the excitation light is changed to 1 to 8 mW, the first in the fluid FIG. 10 shows a prediction result obtained by calculating the distance from the fluid optical element 10 at which the top hat profile is obtained to the imaging device 50, assuming that the absorption coefficient of the laser beam having the wavelength is 2.0 cm ⁻¹ .

  Further, in the laser light source device 1, the laser light L2 of the second wavelength λ2, that is, the light intensity of the detection light detected by the imaging device 50 changes according to the distance from the beam center, and the fluid optical element 10 When the distance d is changed from the imaging device 50 to the imaging device 50, the detected light profile changes as shown in FIG. That is, the laser light L2 having the second wavelength λ2 propagates while expanding the beam diameter as shown in FIG. 11B while maintaining the Gaussian profile at the time of incidence. 10 functions as a concave lens.

  Thus, the fluid optical element 10 functioning as a concave lens can constitute a collimator 20 that converts the laser light collected by the convex lens 15 into parallel light, as shown in FIG. 12, for example.

  In the sample fluid optical element 10, ethanol containing 0.05 g / l of sunset yellow dye was used as the liquid 12. However, the laser light L 1 having the first wavelength λ 1 (wavelength λ 1 = 473 nm). Is absorbed to give a temperature gradient according to the light intensity profile of the laser beam L1 having the first wavelength λ1, exhibiting a lens effect due to the refractive index gradient of the liquid 12 accompanying the temperature gradient, and entering the first The phenomenon itself that imparts the lens effect to the laser light L2 having the wavelength λ2 of 2 could be confirmed even without the dye. That is, the refraction of the laser light entering the rectangular cell (one-dimensional linear temperature gradient in the orthogonal coordinate system) of the single-side cooling and single-side heating in the longitudinal direction can be completely explained due to the temperature distribution. The liquid 12 is not limited to ethanol, and may be a transparent liquid having an appropriate absorption wavelength range.

  Further, when the fluid optical element 10 of the sample confirmed the response immediately after the laser light L1 having the first wavelength λ1 was cut off, the refractive index distribution returned to its original state with the passage of time instead of stepwise. A laser beam L1 having a first wavelength λ1 may be used as the excitation light.

  When the pulsed laser beam L1 having the first wavelength λ1 is used as the excitation light, the temperature decreases as it approaches the center in the cooling process of the laser beam L1 having the first wavelength λ1 during the off period. The state of the reverse temperature gradient can be generated, and the fluid optical element 10 exhibits the effect of a convex lens due to the refractive index gradient of the liquid 12 accompanying the reverse temperature gradient, and has the incident second wavelength λ2. The convex lens effect can be imparted to the laser light L2.

  In the fluid optical element 10 used in the laser light source device 1, an entrance or exit opening 14 is formed on an end surface of the opposite end surface through which the incident light passes and at the end surface on the side where the light focused at a high density passes. The liquid 12 contained in the provided container 11 is a medium having a temperature dependency on the refractive index, and absorbs the laser light L1 having the first wavelength λ1 and transmits the laser light L2 having the second wavelength λ2. Therefore, when the liquid 12 is given a temperature gradient by irradiation with the laser light L1 having the first wavelength λ1, the lens effect due to the refractive index gradient of the liquid 12 accompanying the temperature gradient is exhibited. An arbitrary lens effect according to the light amount profile of the laser beam L1 having the first wavelength λ1 can be given to the incident laser beam L2 having the second wavelength λ2, and the fluid optical In the element 10, desired optical characteristics such as top hat type processing, concave lens and convex lens can be formed in combination with the formation of an appropriate refractive index distribution.

  The liquid 12 contains a dye that absorbs the laser light L1 having the first wavelength λ1, thereby absorbing the laser light L1 having the first wavelength λ1 and laser light having the second wavelength λ2. L2 can exhibit remarkable wavelength selectivity.

  In the fluid optical element 10, the liquid 12 contained in the container 11 is a medium having a temperature dependency on the refractive index, and absorbs the laser light L1 having the first wavelength λ1, and has the second wavelength λ2. The laser beam L2 needs to have wavelength selectivity to transmit.

  Further, the light amount profile of the laser beam L1 having the first wavelength λ1 can be arbitrarily set by the beam shaper 4. For example, the beam shaper 4 has the top of the incident laser beam L2 having the second wavelength λ2. An intensity distribution that imparts the lens effect emitted as a hat beam to the laser light L2 having the second wavelength λ2 may be given to the laser light L1 having the first wavelength λ1.

  Furthermore, by providing the opening 14 on the end surface through which the focused light of the container 11 containing the liquid 12 passes, there is little possibility that the fluid optical element 10 is damaged by the incidence of strong light. The opening 14 is formed to have a small diameter that allows the focused light to pass through, so that the liquid 12 contained in the container 11 forms a meniscus in the opening 14 due to the action of surface tension. It does not flow out of the opening 14.

  For example, a collimator that produces parallel light by changing only the beam system (the diameter of the laser light in a direction perpendicular to the traveling direction of the laser light) without condensing and expanding the laser light with a pair of optical lenses, reduces the beam system. In this case, since the beam collected by the preceding optical lens is incident on the latter optical lens, there was a great restriction on the intensity of the original laser beam in order to prevent damage to this, but the latter optical lens By using the fluid optical element 10 as described above, it is possible to realize a laser processing apparatus capable of processing micro holes with a very large aspect ratio of several hundred nm to several hundred mm.

  For example, as shown in FIG. 13, a laser processing apparatus 100 can be configured using the laser light source apparatus 1.

  The laser processing apparatus 100 includes the laser light source apparatus 1, a table 110 on which a workpiece is placed, the laser light L2 having the second wavelength λ2 emitted from the opening of the laser light source apparatus 1, and the first laser beam L2. And a driving unit 120 that relatively moves the workpiece 200 placed on the table 110 irradiated with the laser beam L2 having the wavelength λ2 of 2 in the x and y directions.

  The laser light source device 1 includes a first laser light source 2 that emits laser light L1 having a first wavelength λ1, a second laser light source 3 that emits laser light having a second wavelength λ2, and a beam shaper 4. The reflecting mirror 5, the semi-transparent mirror 6, and the fluid optical element 10 are provided.

  In the laser processing apparatus 100, the first laser light source 2 of the laser light source apparatus 1 is made of, for example, a semiconductor laser that emits laser light L1 having a first wavelength λ1 (λ1 = 1064 nm). The second laser light source 3 is composed of, for example, a YAG laser that emits laser light L2 having a second wavelength λ2 (λ2 = 1064 nm) and a pulse width Δt (Δt = 4 to 7 ns).

  That is, in the laser processing apparatus 100, the second laser light source 2 outputs an ultrashort pulse laser as the laser light L2 having the second wavelength λ2.

  Further, the fluid optical element 10 is a container in which an entrance or exit opening 14 is provided on an end face on the side through which at least high-density focused light passes through mutually facing end faces through which incident light passes. 11 is a medium having a temperature dependency on the refractive index, and contains a liquid 12 having wavelength selectivity that absorbs the laser light L1 having the first wavelength λ1 and transmits the laser light L2 having the second wavelength λ2. Thus, a temperature gradient is given to the liquid 12 by the irradiation of the laser beam L1 having the first wavelength λ1, and a lens effect due to the refractive index gradient of the liquid 12 accompanying the temperature gradient is exhibited and incident second. The lens effect is given to the laser light L2 having the wavelength λ2.

  Further, the beam shaper 4 gives an intensity to the laser light L2 having the second wavelength λ2 to give the lens effect emitted from the fluid optical element 10 by using the incident laser light L2 having the second wavelength λ2 as a top hat beam. The distribution is given to the laser beam L1 having the first wavelength λ1.

  In the laser light source device 1, the semi-transparent mirror 6 reflects the laser light L 1 having the first wavelength λ 1 emitted from the first laser light source 2 and reflects the second light emitted from the second laser light source 3. The laser light L2 having the wavelength λ2 has a wavelength selectivity for transmission. Then, the laser light L1 having the first wavelength λ1 emitted from the first laser light source 2 is reflected by the semi-transparent mirror 6 and enters the fluid optical element 10 as excitation light. The laser beam L2 having the second wavelength λ2 emitted from the second laser light source 3 is reflected by the reflecting mirror 5, passes through the semi-transparent mirror 6, and enters the fluid optical element 10. The fluid optical element 10 gives a lens effect by the fluid 12 and emits the laser light L2 having the second wavelength λ2 from the opening 14 as a top hat beam. The fluid optical element 10 functions as a concave lens and constitutes a collimator 20 that converts the laser light condensed by the convex lens 15 into parallel light.

  In the laser processing apparatus 100 having such a configuration, in the laser light source apparatus 1, the ultrashort pulse laser emitted from the second laser light source 2 as the laser light L 2 having the second wavelength λ 2 is converted into the convex lens 15 and the fluid optical element 10. The lens effect is imparted by the fluid optical element 10 when the light is converted into parallel light through the collimator 20 constituted by the above-mentioned, so that it can be emitted from the aperture 14 as a top hat beam, High-precision laser processing can be performed by the top hat beam.

  Further, since the laser light source device 1 emits the ultrashort pulse laser as the top hat beam from the opening 14, the high power ultrashort pulse is emitted from the second laser light source 2 as the laser light L2 having the second wavelength λ2. Even if a laser is incident, there is little possibility that the fluid optical element 10 is damaged, and a highly reliable laser processing apparatus 100 can be realized.

  In the laser processing apparatus 100, excitation light absorbed by the fluid 12, that is, laser light L 1 having the second wavelength λ 1 emitted from the first laser light source 2 and processing for passing through the fluid 12. The laser light, that is, the laser light L2 having the second wavelength λ2 emitted from the second laser light source 2 needs to be shifted in wavelength, but the processing laser depends on the material of the workpiece 200 and the processing content. It is also possible to change the wavelength and power of the light and the excitation light, and select the type of medium used as the fluid 12 and the type of dye contained in accordance with the combination of the wavelength of the processing laser light and the excitation light. is there.

  DESCRIPTION OF SYMBOLS 1 Laser light source device, 2 1st laser light source, 3 2nd laser light source, 4 Beam shaper, 5 Reflecting mirror, 6 Semi-transparent mirror, 10 Fluid optical element, 11 Container, 11A, 11B End surface, 11C Copper ring, 12 Liquid , 14 aperture, 15 convex lens 15, 20 collimator, 100 laser processing device, 110 table, 120 drive unit, 200 workpiece, L1 first wavelength laser light, L2 second wavelength laser light,

Claims (13)

A container having an entrance or exit opening provided on an end face on the side where light that has been focused at a high density passes through opposite end faces through which incident light passes, and the refractive index has temperature dependence. A medium containing a liquid having wavelength selectivity that absorbs laser light of the first wavelength and transmits laser light of the second wavelength;
A temperature gradient is given to the liquid by irradiation with the laser light of the first wavelength, and exhibits a lens effect due to a refractive index gradient of the liquid accompanying the temperature gradient,
A fluid optical element characterized by imparting the lens effect to incident laser light having a second wavelength.   The fluid optical element according to claim 1, wherein the liquid contains a dye that absorbs the laser beam having the first wavelength.   2. The fluid optical element according to claim 1, wherein the lens effect corresponding to the light amount profile of the laser light having the first wavelength is imparted to the laser light having the second wavelength.   4. The fluid optical element according to claim 3, wherein the laser light having the first wavelength is irradiated in a state where an intensity distribution is given through a beam shaper.   The beam shaper gives the laser light of the first wavelength an intensity distribution that gives the laser light of the second wavelength the lens effect of emitting the incident laser light of the second wavelength as a top hat beam. The fluid optical element according to claim 4. A first laser light source that emits laser light of a first wavelength;
A second laser light source that emits laser light of a second wavelength;
A container having an entrance or exit opening provided on an end face on the side where light that has been focused at a high density passes through opposite end faces through which incident light passes, and the refractive index has temperature dependence. It is a medium and contains a liquid having a wavelength selectivity that absorbs laser light of the first wavelength and transmits laser light of the second wavelength, and is irradiated with the laser light of the first wavelength. A fluid having a temperature gradient applied to the liquid, exhibiting a lens effect due to a refractive index gradient of the liquid accompanying the temperature gradient, and imparting the lens effect to incident laser light having a second wavelength An optical element,
A laser light source device that emits laser light having a second wavelength to which the lens effect is imparted.   7. The laser light source device according to claim 6, wherein the liquid contains a dye that absorbs the laser light having the first wavelength.   7. The laser light source device according to claim 6, wherein the lens effect corresponding to the light amount profile of the laser light having the first wavelength is imparted to the laser light having the second wavelength. A beam shaper that gives an intensity distribution to the laser light of the first wavelength;
9. The laser light source device according to claim 8, wherein the fluid optical element irradiates the liquid with the laser light having the first wavelength through the beam shaper with an intensity distribution given thereto.   The beam shaper has an intensity distribution for giving the lens effect emitted from the fluid optical element as a top hat beam to the incident laser beam having the second wavelength to the laser beam having the first wavelength. The laser light source device according to claim 9, wherein the laser light source device is applied to laser light. A first laser light source that emits a laser beam having a first wavelength, a second laser light source that emits a laser beam having a second wavelength, and at least high density of end faces facing each other through which incident light passes. A container having a temperature-dependent refractive index in a container provided with an entrance or exit opening on the end face on the side through which the focused light passes, and absorbs laser light of the first wavelength, The laser light of the second wavelength contains a liquid having wavelength selectivity to transmit, and a temperature gradient is given to the liquid by irradiation of the laser light of the first wavelength, and the liquid of the liquid accompanying the temperature gradient is supplied. A fluid optical element that exhibits a lens effect due to a refractive index gradient and imparts the lens effect to the incident second wavelength laser beam, and the fluid using the incident second wavelength laser beam as a top hat beam Out of optical element A beam shaper that imparts an intensity distribution to the laser light of the first wavelength that imparts a lens effect to the laser light of the second wavelength, and the lens effect is imparted by the fluid optical element to the second wavelength. A laser light source device that emits the laser beam as a top hat beam from the opening;
A table on which a workpiece is placed;
Drive means for relatively moving the laser light of the second wavelength emitted from the opening of the laser light source device and the workpiece placed on the table irradiated with the laser light of the second wavelength. Laser processing apparatus provided.   The laser processing apparatus according to claim 11, wherein the liquid contains a dye that absorbs the laser light having the first wavelength.   12. The laser processing apparatus according to claim 11, wherein the second laser light source outputs a pulsed laser beam as the laser light having the second wavelength.

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