JP2014004631A - Femtosecond laser processing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a femtosecond laser processing machine making it possible to shorten a required time by expanding a processed area of irradiation per work time, which is related to a versatile labor-saving processing method, in processing that employs a femtosecond laser.SOLUTION: A light-source beam 21 oscillated from a femtosecond laser oscillator 19 is separated into a primary optic-axis beam 1 and plural branch beams 2 and 3 whose optical lengths are different from each other. An integrated beam 4 to and on which the primary optic-axis beam 1 and branch beams 2 and 3 are returned and concentrated is introduced into a condenser lens 7 in order to cause a time lag at the time of irradiation due to the difference in the optical length between the plural branch beams 2 and 3. The lens center position of the condenser lens 7 is deviated from the optical-axis center of the integrated beam 4. In addition, the condenser lens 7 is rotated about the optical-axis center of the integrated beam 4. Further, a work 41 that is an object of processing is moved, and the work 41 is continuously irradiated, whereby an irradiation trajectory is horizontally moved along the plane to be processed of the work 41, and thus shaped like a horizontal spiral. Besides, an irradiation focal area is expanded in an arc-like form.

Description

The present invention relates to a femtosecond laser processing machine for expanding an irradiation focal region and a processing method therefor.

Conventional processing using a laser beam has been widely used for various purposes such as cutting and bending of metal and wood.

In particular, a so-called CO2 laser that injects carbon dioxide gas to the laser beam is used as the mainstream of such laser processing, and the processing method has been expanded in various directions at once because high-precision finishing is intended.

However, this CO2 laser is inevitably accompanied by high-temperature processing, and further research is being conducted on changes to the internal stress of the material and processing by heating and melting, as well as processing accuracy, with respect to the workpiece to be processed. Is an issue.

Under such circumstances, an ultrashort pulse laser called a femtosecond laser has been attracting attention as a practical application of a laser processing method that has been developed in the United States and does not generate heat that cannot be achieved by conventional laser processing.

Thus, the unique characteristics of femtosecond lasers have attracted attention from various research institutions and experiments have begun. Such data can also be shown on the Internet. The characteristic of the laser is an ultra-short pulse laser as the name suggests, and the fact that ultra-fine processing can be performed and the information on non-thermal processing have inevitably attracted the attention of related companies.

In particular, in the femtosecond laser, the unit of irradiation time is femto, which is 1/100 trillion seconds, and the irradiation focus of the femtosecond laser operates based on this number.

In addition, the biggest difference from the conventional laser processing method is that the experiment is based on a center wavelength of 800 nm. When a femtosecond laser is used, scanning of the metal surface in the processing of Si wafer carbon chrome steel has an uneven height difference of 300 nm. Details of the minute cycle of the concavo-convex structure of 5000 per second are disclosed, and the experimental results of the topical non-thermal processing when the irradiation source is 5 KHz are also disclosed.

On the other hand, with regard to femtosecond lasers, test results based on various implementation conditions were announced, and as a noticeable laser, precision microfabrication was possible, and it did not affect the amount of heat on the processing machine, and it was not heated to the industry. It is natural that attention is paid.

However, in the ultrafine processing, it takes a long time to process the required area of the desired region due to the excessive fineness, and this required processing time has become a problem. There is currently no superfine processing, but in the general processing industry, however, there are very few types of processing industry that require processing with femto precision units.

The remarkable characteristics obtained for the development of this femtosecond laser should be taken advantage of, and when considering the unit of processing of 1/100 trillion cycle, processing time is a problem for profitability in the processing base. This is an unavoidable reason. The focal diameter of the laser is said to be 10 micrometers, which indicates problems in ultrafine processing and processing operations.

JP 2003-334683 A JP 2003-194719 A JP 2004-216430 A JP 2008-296269 A JP 2008-200699 A JP 2009-160625 A JP 2009-50904 A JP 2009-28766 A

As mentioned above, it has been announced that femtosecond lasers based on 1/100 trillion seconds have various special characteristics, such as non-thermal processing, 800 nm frequency, etc. It is necessary to obtain profitability in the general-purpose processing market by taking advantage of these characteristics such as high density and non-thermal processing in the experimental values with 5000 traces of irregularities. In addition, with regard to the usage requirements for nanometer-to-micrometer fine reference versus processing speed per unit time, taking advantage of this remarkable characteristic, increasing the processing speed and facilitating the use of current general-purpose CO2 lasers. Is an issue.

It is said that the diameter of the focal point obtained by irradiation with the femtosecond laser is about 10 micron, and if it is desired to process a length of 100 mm, the required processing time can be calculated by calculating the processing length of 100 mm with the diameter of 10 micron. Can be calculated easily, but takes a long time. At this processing speed, there is no rationality. This is because it is necessary to apply a continuous irradiation focus of 10 μm for a long time here, and the essential conditions for general-purpose machining are the existence of the thickness and depth t of the workpiece, and labor saving cannot be expected.

Compared with the irradiation area of the focus of 10 micro diameter per unit time of the femtosecond laser, the irradiation processing area is expanded with respect to the processing amount per the same time as the known femtosecond laser processing, and the irradiation focus by this expansion effect The area is close to the profitability of the general processing industry when irradiation is completed within the same time.

With the processing area per unit time of the femtosecond laser irradiation focus per unit time of 10 micro diameter, the irradiation area is expanded per unit time with the surface roughness of 5000 irregularities per second, and the workpiece for the expanded area The feed time is approximated to the general process profitability by calculating the traveling speed corresponding to the volume. Therefore, a remarkable predetermined effect was obtained.

Here, as described above, there is a research publication using 5000 shots / second at 5 kHz, and considering the number of shots processed according to the present invention, 1000 shots / second was obtained for actual measurements at 1 kHz, and this 1000 shots / second. The above-mentioned profitability solution has been obtained with emphasis on the operation method of the sliding table in expanding the irradiation range instead of irradiation at the same location. That is, an irradiation range that matches the purpose of zeroing the focus margin for irradiation that matches KHz was obtained. Hereinafter, the irradiation focus is an image formation of the beam light by the optical means of the focus, and indicates that the irradiation is a process before reaching the focus.

In order to achieve the above object, the femtosecond laser processing machine of the present invention splits a light source beam oscillated from a femtosecond laser oscillator into a plurality of branched beams having different main optical axis beams and optical path lengths, and An integrated beam obtained by recursively condensing the main optical axis beam and the branched beam is guided to a condenser lens, and a time lag at the time of irradiation is generated due to a difference in optical path length of the plurality of branched beams. The lens center position of the condenser lens is decentered with respect to the optical axis center, the condenser lens is rotated around the optical axis center of the integrated beam, and the workpiece to be processed is moved to move the workpiece. By continuously irradiating, the irradiation trajectory is formed into a horizontal spiral shape horizontally moved along the work plane of the workpiece, and the irradiation focus is formed in an arc shape. It is intended to expand the product.
A lens eccentric position adjust for decentering the lens center position of the condenser lens by moving the lens center position in a horizontal direction with respect to the optical axis center of the integrated beam; and the lens eccentric position adjustment includes a nut, An adjusting screw that is screwed onto the nut, the nut is fixed to a lens holder to which the condenser lens is mounted, and the rotation axis is aligned with the optical axis center of the integrated beam, and is rotatable. The adjusting screw is provided on a rotating base on which the lens holder is installed.

The present invention is an irradiation processing machine using a femtosecond laser, and in the course of transmission, a light source beam emitted from a femtosecond laser oscillator is divided into a main optical axis beam and a branched beam having different optical path lengths, and then all the beams are integrated. Condensed as a beam, guided to a holder equipped with a lens in the light receiving head, the center of the optical axis of the integrated beam and the rotation axis of the rotation base are concentric circles, and the light receiving head to the eccentric position with respect to the integrated beam By sliding and fixing, the center of the lens generates and maintains a separation distance in contrast to the center of the integrated beam optical axis, and the rotation operation of the rotation base is added to the generation of the separation distance, thereby creating an arc by the separation distance. In the machining where the irradiation area is enlarged and the irradiation shape of the workpiece to be machined is formed into a spiral shape by operating the slide table, the irradiation is continuous. And characterized in that to create the irradiated region larger keeping the surface homogenized irradiation area per unit time imaging of focal position by gaps irradiation.

Furthermore, the present invention helps to generate a time lag by splitting the main optical axis beam obtained by diverting the light source beam of the femtosecond laser oscillator into a plurality of branched beams having different optical path lengths. By guiding the branched beam back to the main optical axis to the light receiving head as an integrated beam, the slide table is advanced simultaneously to create a spiral shape by equalizing the irradiation density of the enlarged area by the above-mentioned means. It is characterized by doing.

In the present invention, irradiation is performed after the main optical axis beam branched by the branching unit and immediately before branching to the branching beam, or immediately before returning the branched beam to the light receiving head by collecting the branched beam. By providing a shutter for controlling the uniform density, it is possible to irradiate the light receiving head with an optical path obstruction or continuous or gap optical path adjustment.

In the present invention, the lens of the light receiving head is formed by laminating and integrating the first lens and the second lens, and the first lens is a composite in which the spherical aberration is suppressed to a minimum and the high refractive index lens is bonded to the low refractive index lens. The second lens is a special cylindrical lens that controls the diffusivity of the focal point.

In the present invention, in the creation of an enlarged irradiation area, the rotation axis of the rotation base on which the holder equipped with the lens of the light reception head is mounted and the optical axis center of the integrated beam are made to coincide with each other. In the integrated beam guided to the holder, the irradiation enlarged position is created by the eccentricity that forms the arc by the rotation of the rotation base.

According to the present invention, the enlarged irradiation region created by the eccentricity and rotation of the integrated beam performs variable eccentricity, rotational speed control of the rotation base, and simultaneous two-axis automatic control of the workpiece used in combination with these. . It has a sliding table with variable travel speed control, and has a single-step inching test for each operation by inching and an automatic switching control function.

In the present invention, when three elements that are the basis of the above-described configuration situation are aggregated, a plurality of branched beams become integrated beams by a return optical path, and this optical axis generates a time lag of irradiation time in condensing and irradiation, Irradiation within the irradiation focal point enlargement area and focal point scattering. This is the first element of the present invention. The center of the optical axis of the converged integrated beam and the rotation axis of the rotary base that firmly supports the holder as the light receiving head are concentric circles. In this concentric state, the holder is moved to a predetermined position at the center of the rotary base. In the rotation of the rotation base, this eccentric position forms an arc as the irradiation focal point in the passage of the integrated beam. This is the second element. The beam of light emitted from the integrated beam due to this separation forms a focal locus due to refraction of the lens by rotation as shown in FIG. This is the irradiation focal area, which is a large focal area difference from the irradiation trajectory of a normal femtosecond laser. This is the third element, which is characterized in that the operability of the movable table is greatly affected by merging with the first, second and third elements. Note that the optical axis control shutter also strongly assists the first element.

The irradiation area per unit time can be expanded, and fine processing can be realized in a short time. High-precision fine processing can be realized by non-heat treatment processability.

The perspective view which shows a light receiving head. (A) Irradiation locus | trajectory figure by the sliding table action | operation at the time of irradiation by making the amount of eccentricity into zero. (B) The irradiation area expansion area locus diagram of irradiation rotation provision in the case of eccentricity. The figure of each irradiation locus of the integrated beam by the eccentric movement of the holder. (A) Irradiation locus diagram when the center of the holder to which the lens is attached and the center of the integrated beam optical axis are matched. (B) Irradiation locus diagram when the integrated beam is fixed at the center position and the holder is moved to the right with respect to the integrated beam. (C) Irradiation locus diagram when the integrated beam is stationary at the center and the holder is moved eccentrically to the left with respect to the integrated beam. (D) The figure which shows the circular arc irradiation locus | trajectory of the integrated beam by lens refraction when a holder is moved eccentrically and rotated on a rotation base. The figure which shows the whole structure of the femtosecond laser processing machine by this invention. The figure which shows the cylindrical lens form and characteristic in a light receiving head. (A) Three-dimensional formation of a cylindrical lens is shown, and the following is an enlarged view. (B) Focal image of the basic shape of the lens. (C) Irradiation focus imaging figure by lens lamination | stacking of the holder in a light receiving head. (D) The imaging figure of (c) by use of the said lens. (A) The holder top view fixed to the eccentric position on a rotation base. (B) FIG. 6 (a) is a diagram showing the relationship between the holder and the rotation base at the eccentric position according to the section AA.

As a basic form irradiation of an irradiation source of 1 KHz, a pulse width of 120 femtoseconds, a center wavelength of 800 nm, a repetition frequency of 1 KHz and a base of 1000 shots / second are shown as operation modes as examples. The setting of 1 kHz and 1000 shots / second is for eliminating waste of overlapping irradiation in the irradiation focal point locus, labor saving, and operability.

Hereinafter, the femtosecond laser processing machine of the present invention was set for the purpose of obtaining profitability in the general processing industry by expanding the irradiation area working per unit time and expanding the processing area per unit time.

FIG. 4 shows the overall configuration of the femtosecond laser processing machine. A light source beam 21 emitted from the femtosecond laser oscillator 19 is branched into a main optical axis beam 1 and a measurement monitoring beam by a branching unit 47 and sent to a measuring unit 28.

As shown in FIG. 4, the main optical axis beam 1 passes through the shutter 45 and is branched into the branch beam 2 and the branch beam 3 by the branching unit 8. The optical path lengths of the branched beams 2 and 3 are made different. Each of the branched beams 2 and 3 irradiates the light receiving head 5 with a difference in the light receiving speed according to the optical path length, merges with the main stream, returns and condenses, generates a time lag, and uses a frequency shape shift of the femtosecond laser. While making the density uniform, the integrated beam 4 passes through the shutter 46 and passes through the condenser lens 7 (the first lens 71 and the second lens 72) in the holder 24.

As shown in FIG. 1, the holder 24 to which the lens 7 is attached can be eccentric with respect to the integrated beam 4 by the lens eccentric position adjustment 25. When the lens 7 is decentered, the lens position is separated from the rotation axis of the rotation base 9. By aligning the rotation axis of the rotary base 9 with the optical axis center 201 of the integrated beam 4, rotating the rotary base 9 to rotate the arc, and moving the work 41 in the traveling direction 14 of the slide table 40. As shown in FIG. 2B, the irradiation focal locus of the workpiece 41 can be formed in a spiral shape.

FIG. 2 shows the enlargement of the irradiation area of the present invention.
In (a), the eccentric amount of the lens 7 with respect to the integrated beam 4 is zero, the optical axis center 201 of the integrated beam 4 is aligned with the center of the holder 24, and the rotating base 9 is rotated or the sliding table is rotated. The irradiation focal locus when moving 40 is a conventional irradiation locus.
(B) is an irradiation locus when the lens 7 is decentered with respect to the integrated beam 4, the rotation base 9 is rotated, and the sliding table 40 is moved. The irradiation locus is spiral. The amount of eccentricity of the lens 7 with respect to the integrated beam 4 is adjusted by a lens eccentric position adjustment 25. By reducing the traveling speed 106 of the sliding table 40 in the irradiation by the eccentric holder 24, the irradiation focal spot density increases the focal amount. Thereby, the irradiation density of the workpiece 41 is controlled by the traveling speed 106 of the sliding table 40.

FIG. 3 shows an irradiation locus of the integrated beam 4 due to the eccentric movement of the holder 24.
(A) Irradiation locus when the central axis (center position) 202 of the lens 7 of the holder 24 to which the lens 7 is mounted and the optical axis center 201 of the integrated beam 4 are matched.
(B) An irradiation locus when the holder 24 is moved eccentrically to the right with respect to the integrated beam 4.
(C) Irradiation locus when the holder 24 is moved eccentrically to the left with respect to the integrated beam 4.
(D) An arc generation irradiation locus in rotation of the holder when the holder 24 is eccentric and rotated by the rotation base 9 is shown.

When there is no eccentric amount with respect to the integrated beam 4 of the lens 7 and the rotation axis of the rotation base 9 and the center of the holder 24 coincide, the irradiation locus becomes a concentric circle as shown in FIG. I can't make it. The same focal shape as the operation of the conventional femtosecond laser is irradiated for ultrafine surface processing.

When the lens 7 is decentered with respect to the integrated beam 4, as shown in FIG. 3D, the irradiation focus becomes a spiral shape when the table is advanced to the work 41 of the femtosecond laser. 3D is an irradiation area obtained by combining (b) and (c) of FIG. 3, and the rotation base 9 makes the distance of the irradiation focal point at each lens position the arc radius 203 of the irradiation area expansion area. As shown in FIG. 3D, an arc is formed by the focal position 104 due to the eccentricity. This is the maximum rotational diameter range 208. The rotation of the rotary base 9 results in arc-shaped irradiation, and the irradiation focus area is enlarged.

The table traveling speed 106 of the sliding table 40 is determined by the relationship of the material form such as the workpiece material and the thickness, and the femtosecond laser processing machine performs irradiation with a large number of overlapping shots per time to separation state irradiation with no overlapping amount. Is controlled to obtain an adjustment of optimization of the irradiation density that matches the processing conditions. Incidentally, the irradiation density indicates the condensing range of the focal point.

FIG. 1 shows a configuration of a light receiving head 5 of the present invention. The light receiving head 5 includes a holder 24, a rotation base 9, a lens eccentric position adjustment 25, and the like. On the rotary base 9, a holder 24 on which the lens 7 is mounted and a lens eccentric position adjust 25 are provided.

The lens eccentric position adjust 25 has a function of decentering the position of the lens 7 with respect to the integrated beam 4. The lens eccentric position adjuster 25 supports the holder 24 to which the lens 7 is attached from both sides, and can move the position of the lens 7 as shown by a movement locus 49 in FIG.

FIG. 5 shows a cylindrical lens.
(A) shows the basic shape of the outer mold of the cylindrical lens.
(B) shows the state of the whole surface irradiation when used in the original cylindrical lens, and shows the locus on which the image of the irradiation focal point is formed in a straight line.
(C) shows a shape using the cylindrical lens 72 of the present invention, and is a combined focal form of irradiation with the lens 71. In this case, the cylindrical lens form is preferably cylindrical (a ′) for mounting the holder.
(D) is a figure of the irradiation area expansion region of the (c) figure of FIG. Regardless of the position where the irradiation focus is decentered, focus imaging as shown in (c) and (d) can be performed to obtain a normal irradiation focus shape. The outline of the focal point usually has an arc shape, but the side of the focal point due to the fine irradiation focus of the femtosecond laser may cause a situation such as a pinpoint blur as the holder 24 moves eccentrically. This shows a mold that corrects.

Since the lens eccentric position adjustment 25 is supported and fixed on both side surfaces of the holder 24, a nut 26 block screwed into the adjustment screw 29 is fixed to the holder 24 on one side. The symmetrical side is a ground shaft, and a guide rail slider is used on the outer periphery of the shaft, and the slider is fixed to the symmetrical side with a nut 26. Both ends of both shafts are support metals 27, and are fixed to the rotation base 9, so that the rotation base 9, the lens eccentric position adjustment 25, and the holder 24 to which the lens 7 is attached are integrated. When the holder 24 is eccentric and fixed, and the rotation base 9 is rotated, the integrated beam 4 passes through the holder 24 at the eccentric position, and the irradiation locus creates an arc. The irradiation area can be expanded by the arc. A fitting nut 26 is fitted with a lock nut (not shown) in the adjusting screw 29.

In the lens 7, a first lens 71 and a second lens 72 are arranged in a stacked manner. The first lens 71 is an integrated lens in which two low-refractive-index crown glass lenses and concave-convex high-refractive-index meniscus lenses are bonded together, and is excellent in correcting aberrations and improving imaging performance with respect to light. The lens configuration also suppresses minute spherical aberration.

A cylindrical lens is used as the second lens 72. FIG. 5 shows a cylindrical lens. A cylindrical lens is an irregular lens with a flat surface on one side. A normal circular lens forms an image in the form of a dot, but in a cylindrical lens, the opposite surface of flat molding is formed into a concentric chord shape in one full length direction. In this case, the focal point is linearly formed as shown in FIG. 5B and fused with the refractive conversion of the lens 71, and the diffusibility of the focal point is extremely suppressed and clear as shown in FIGS. 5C and 5D. To form an image. By using a linear focal point over the entire length of this characteristic, it is possible to prevent and correct the spread of the focal point in a variety of fixed positions where the amount of decentration of the focal position of the integrated beam 4 is uncertain due to the change of the eccentric position of the lens. To obtain a clear image.

FIG. 6A is a plan view in which the holder 24 is fixed to the eccentric position on the rotary base 9. The rotation base axis of the rotation base 9 is concentric with the optical axis center 201 of the integrated beam 4, and the holder 24 is eccentrically fixed on the rotation base 9 as shown in the figure, so that the integrated beam optical axis abutting on the lens 7 abuts. The contact position is displaced. The rotation of the rotation base 9 generates a separation distance between the lens center of the holder 24 at the eccentric position, the rotation base rotation axis, and the circle center of the integrated beam optical axis center 201, and this separation distance is the rotation base rotation axis. Create an arc by rotating the heart.

FIG. 6B is a cross-sectional view showing the eccentric position of the holder 24 at the A-A portion of FIG. 6A, and also shows the displacement of the focal point due to the rotation of the integrated beam 4 and the rotation base 9. ing. That is, the contact position of the center of the symmetrical lens holder 24 with respect to the optical axis of the integrated beam 4 is displaced by the rotation of the rotation base 9. FIG. 6A is a cross-sectional view taken along the line A-A in FIG. 6A showing that this situation is that the focal point 104 is displaced as the focal point 107 is rotated due to the start of irradiation at the eccentric position, and that the displacement 208 becomes the diameter of the irradiation area. It is.

The workpiece 41 is mounted on a sliding table 40, and the sliding table 40 operates in the X and Y axes, and can perform circular operation by simultaneous two-axis control such as automatic forward feed, pitch control, and fixed position focus.

The driving speed of the sliding table 40, the rotation speed of the rotary base 9, and the like are performed by a speed control continuously variable transmission motor (not shown). The rotation speed is calculated based on 1000 shots / second in this embodiment.

By the above method, the irradiated focal area of the work 41 per unit time is expanded, and in addition to the number of irradiation shots, the processing feed rate corresponding to the eccentric amount can be increased as compared with the conventional single irradiation.

As a suitable condition of the material of the workpiece 41 with respect to the rotation speed in the rotation base 9, a continuously variable transmission motor can be used as a motor (not shown) for rotation so that a desired machining rotation speed can be obtained. In accordance with the time lag due to the difference in the branched optical path, the beam continuity, gap, interference, uniformity of the state of the irradiation focus in the irradiation expansion area and irradiation density by the appropriateness of the windows of the shutters 45 and 46, and the blank opposite to the overlap amount of the irradiation focus The solution to the malfunction of the parts and the shutter control are also implemented by the control of the continuously variable transmission motor. The labor saving problem is solved by controlling the forward speed of the table 40. The irradiation site optimization speed can be confirmed on the screen of the control panel 33, and means for controlling the optimization of conditions is provided. The inflection machining operation, which is the best means for ensuring the conformity conditions, is an indispensable measure for obtaining certain numerical values. The best numerical value obtained by inching is to operate the inching button and the target numerical value can be obtained. The automatic control process can be realized by registering with the confirmation button and switching. Alternatively, it is possible to solve the surface roughness of the processed surface by the relational value obtained from the inching. That is, the numerical values for the rotation speed of the rotary base 9 and the traveling speed 106 of the table 40 are stored, and the stable operability of automatic control can be realized. The femtosecond laser processing machine is characterized in that the uniformity of the irradiation focus within the enlarged region and the irradiation density information are achieved by the memory function possessed by this machine.

The control system of the femtosecond laser beam machine of the present invention is displayed and controlled by the control panel 33. The continuous irradiation of the integrated beam 4 and the control of the gap irradiation are performed by the rotation of the shutter 46. During the rotation, the circular shutter 46 is a cut-out window-like window provided on the flat surface, and the integrated beam 4 passes and is blocked. Done. After the main optical axis beam 1 separated by the branching unit 8 in the surface roughness of the processing surface and before the splitting into the beams 2 and 3, or the branching beams 2 and 3 are recursively collected by the collector 48, Before being guided to the light receiving head 5, shutters 45 and 46 are provided, respectively, so that light can be focused on the light receiving head 5 continuously or with a gap. Depending on the purpose of creating an irradiation area enlargement area, control such as stopping one of the two shutters 45 and 46 can be performed, and the irradiation area is made uniform along with the time lag irradiation of the integrated beam 4. The measuring unit 28 is configured by a personal computer and can be used as a data measurement control unit to confirm a desired effect.

The control box 34 manages the beam branched from the main optical axis beam 1 by the splitter 47 and controls the entire femtosecond laser beam machine in cooperation with the measuring unit 28. The control panel 33 stores operation system software related to the processing method, and holds software such as control related to push buttons of the control panel 33 and inching control. Built-in memory function to control power source. The inching is a processing procedure for only a single operation and is automated by operating the switching button after confirming the inching test.

On the control panel 33 screen, necessary items such as the start display of the rotary base 9, the start rotation and speed of each motor, and the eccentricity confirmation position display are displayed. The push button position is manually operated and displayed. Match the necessary items of the part to the instruction name and decide by manual rotation. It operates by pushing the push button at the center of rotation, and can be moved. In this case, the power supply is displayed on the display screen as electrical specifications. The power supply and emergency stop button are independent. In addition, unnecessary data on the display screen is deleted, and the user company has a function of collecting only necessary conforming data.

Further, in the irradiation processing machine using the femtosecond laser, the light source beam 21 oscillated from the femtosecond laser oscillator 19 is divided into the main optical axis beam 1 and the plurality of branched beams 2 and 3 having different optical path lengths. The integrated beam 4 obtained by converging the optical axis beam 1 and the branched beams 2 and 3 is led to a light receiving head 5 provided with a condensing lens 7, and further, the lens holder for the light receiving head 5 installed on the rotating base 9. Reference numeral 24 denotes an optical axis of the integrated beam 4 while rotating the rotating base 9 concentrically in accordance with the optical axis center 201 of the integrated beam 4 in a state where the rotating base 9 is moved and decentered with respect to the rotational axis of the rotating base 9. The workpiece 41 to be machined in the movement by the simultaneous two-axis control of the X axis and the Y axis in the travel allowing the circular trajectory with respect to the center 201 (on the circular trajectory). Is formed in a spiral shape irradiated by continuous irradiation is characterized by enlarging the irradiation focus area in an arc shape.
Further, due to the irradiation area expansion, the surface roughness of the irradiation area expansion area causes a time lag at the time of irradiation due to the difference in the optical path lengths of the plurality of branched beams 2 and 3, and the sliding table 40 advances simultaneously. In this irradiation, the irradiation density can be made uniform by expanding the irradiation area by the spiral-shaped focal locus, and the desired density of the surface roughness can be obtained.
Further, the main optical axis beam 1 is used as a mainstream, and is formed into a plurality of branched beams 2 and 3, and after regression focusing, the time lag due to the irradiation time difference is measured by the optical path difference, and the surface roughness of the irradiation area expansion region is measured. In order to control the uniformity of the irradiation density, the optical path blocking shutters 45 and 46 are provided to control the overlapping amount of the focal locus in the movement of the irradiation focal point due to the eccentricity, and to control the optical axis adjustment of the continuous or gap. It has the effect characterized by having the function to perform. By using a plurality of shutters 45 and 46, control of generation of the focal overlap amount due to movement of the irradiation focal point due to eccentricity and control of the irradiation density through the lens for fine processing by a conventional method are performed. Can do.
In addition, the lens 7 in the light receiving head 5 having the above-described structure integrates the first lens 71 and the second lens 72 by stacking, and the first lens 71 also suppresses a minute spherical aberration, and the low refractive index lens has a high refractive index. This is a compound lens in which lenses are bonded, and the second lens 72 has an effect characterized in that the formation of a focal contour is obtained by using a special lens cylindrical lens that controls the diffusibility of the focal point. is there.
Further, in creating the irradiation area enlargement region, the rotation axis of the rotation base 9 on which the holder 24 to which the lens 7 of the light receiving head 5 is mounted is aligned with the optical axis center 201 of the integrated beam 4, and then the rotation base 9 In the integrated beam 4 guided to the lens holder 24 by the mechanism for moving the holder 24 of the light receiving head 5 away from the rotation axis, an arc is created by refracting the light beam through the rotation of the rotating base 9. In addition, in adjusting the irradiation area expansion region by the amount of eccentricity and stopping the rotation, the same ultrafine processing as the conventional processing method can be achieved.
Further, the enlarged irradiation region created by the eccentricity and rotation of the integrated beam 4 has a variable amount of eccentricity, a rotational speed control of the rotation base, and a traveling speed for performing simultaneous two-axis automatic control of the workpiece used in combination with these. Equipped with variable control slide table 40, single-step inching test of each operation by inching is performed. It is characterized by ensuring appropriate numerical values, storing function, and automatic switching control function.

As described above, the femtosecond laser processing machine of the present invention splits the light source beam 21 oscillated from the femtosecond laser oscillator 19 into the main optical axis beam 1 and the plurality of branched beams 2 and 3 having different optical path lengths. At the same time, the integrated beam 4 obtained by recursively condensing the main optical axis beam 1 and the branched beams 2 and 3 is guided to the condenser lens 7, so that the difference in optical path length between the plurality of branched beams 2 and 3 is caused. A time lag is generated at the time of irradiation, the lens center position 202 of the condenser lens 7 is decentered with respect to the optical axis center 201 of the integrated beam 4, and the condenser lens 7 is rotated around the optical axis center 201 of the integrated beam 4. Further, by moving the workpiece 41 to be processed and continuously irradiating the workpiece 41, a horizontal spiral in which the irradiation locus is horizontally moved along the processing plane of the workpiece 41. Causes formed Jo, so to expand the irradiation focus area in an arc shape, to enlarge the illumination area per unit time, a short time can be realized fine processing. High-precision fine processing can be realized by non-heat treatment processability.

The lens center position 202 of the condensing lens 7 is provided with a lens eccentric position adjust 25 for moving the lens center position 202 in the horizontal direction with respect to the optical axis center 201 of the integrated beam 4 and decentering the lens. 26 and an adjusting screw 29 that is screwed onto the nut 26, the nut 26 is fixed to the lens holder 24 to which the condenser lens 7 is mounted, and the rotation axis is centered on the optical axis center 201 of the integrated beam 4. Since the adjusting screw 29 is provided on the rotary base 9 that can be rotated together and on which the lens holder 24 is installed, the amount of eccentricity of the condenser lens 7 for expanding the irradiation focal area can be easily and highly accurate. Can be adjusted.

By expanding the irradiation area per unit time, processing with femtosecond laser characteristics in a short time is performed, and even the ultra-short pulse laser and the irradiation focus processing part can be miniaturized, making it a general-purpose market The processability of surface roughness from micrometer to nanometer can be implemented, and it will be a step toward practical use of general-purpose laser without losing the internal stress of the processed material due to the non-heat treatment processability approaching the general-purpose practical use. Can get the effect. It is a method of use in a result called 1 shot 10 micro diameter. In the future, in the processing of the micro and nano areas, it can be expected to suddenly be used in various directions, and by the shift to general-purpose machines, the IC industry, the metal processing industry, The industrial area can be expanded by the resin industry, woodworking industry and its labor-saving functions.

DESCRIPTION OF SYMBOLS 1 Main optical axis beam 2 Branch beam 3 Branch beam 4 Integrated beam 5 Light receiving head 6 Eccentric beam line 7 Lens 71 1st lens 72 2nd lens 8 Branch device 9 Rotation base 10 Branching. Beam irradiation light 11 Eccentricity 13 Focus 14 Sliding table traveling direction 18 Femtosecond laser oscillation assembly 19 Femtosecond laser oscillator 20 Excitation laser 21 Light source beam 23 101, 102 Light receiving rotation 24 Holder 25 Lens eccentric position adjustment 26 Nut 27 Support metal 28 Measuring unit 29 Adjusting screw 30 Stretcher 31 Compressor 32 Rotating belt 33 Control panel 34 Control box 39 Reflecting mirror 40 Sliding table 41 Work 42 Amplifying system 43 Machine mounting bracket 44 Table speed trajectory 45 Shutter 46 Shutter 47 Branching device 48 Condensing Instrument 49 Movement locus 50 Linear focus 51 Irradiation line 52 Side correction 101 First beam focus 102 Second beam focus 103 Third beam focus 104 Focal position due to eccentricity 106 Table traveling speed 107 Focal locus due to rotation 108 Focal width of cylindrical lens 109 Focal locus due to eccentricity 200 Shot central locus 201 Beam optical axis center 202 Lens central position 203 Eccentric width (radius)
208 Maximum rotation diameter range 209 Shot trajectory diameter 1000 shot trajectory for 210 seconds

Claims (2)

The light source beam (21) oscillated from the femtosecond laser oscillator (19) is divided into a main optical axis beam (1) and a plurality of branched beams (2) and (3) having different optical path lengths, and the main light. The integrated beam (4) obtained by recursively concentrating the axial beam (1) and the branched beams (2) (3) is guided to the condenser lens (7), and the plurality of branched beams (2) (3) Due to the difference in the optical path length, a time lag occurs at the time of irradiation,
The lens center position (202) of the condenser lens (7) is decentered with respect to the optical axis center (201) of the integrated beam (4), and the condenser lens (7) is attached to the integrated beam (4). By rotating around the optical axis center (201), further moving the workpiece (41) to be machined, and continuously irradiating the workpiece (41), the irradiation trajectory is the plane to be machined of the workpiece (41). The femtosecond laser processing machine is characterized in that it is formed into a horizontal spiral shape that is horizontally moved along an arc and the irradiation focal area is enlarged in an arc shape. A lens eccentric position adjustment (25) for moving the lens center position (202) of the condenser lens (7) in the horizontal direction with respect to the optical axis center (201) of the integrated beam (4) to decenter the lens. Prepared,
The lens eccentric position adjustment (25) includes a nut (26) and an adjustment screw (29) screwed into the nut (26).
The nut (26) is fixed to the lens holder (24) to which the condenser lens (7) is attached,
The adjustment screw (29) is attached to a rotation base (9) which can be rotated with its rotation axis aligned with the optical axis center (201) of the integrated beam (4) and on which the lens holder (24) is installed. The femtosecond laser processing machine according to claim 1 provided.

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