TW201315559A - Laser cutting method and apparatus - Google Patents

Abstract

A laser cutting method and apparatus, adapted for cutting a machining part formed with a top and a bottom at positions opposite to one another while allowing a machining thickness to be formed between the top and the bottom in a direction parallel to an axial direction, comprising the steps of: projecting a laser beam that is emitted from a laser source to the machining part; enabling the laser beam to travel through a lens while being projected toward the top so as to be focused onto the bottom of the machining part; enabling the laser beam to form a first modification trajectory on the bottom of the machining part; changing the projection location of the laser beam at least once in a direction parallel to the axial direction for establishing at least one zoom focus point on the machining part while enabling the projection of the at least one zoom focus point in a direction parallel to the axial direction to be located on the first modification trajectory; enabling the laser beam to form a zoom modification trajectory based upon the zoom focus point while allowing the projection of the zoom modification trajectory in a direction parallel to the axial direction to overlap with the first modification trajectory so as to stabling a continuous modification interface inside the machining part between the first modification trajectory and the zoom modification trajectory.

Description

Laser cutting method and device

The invention relates to a laser cutting method and device, in particular to a continuous reforming interface formed by rising from the bottom of the workpiece to the top, non-destructive processing of the workpiece, suitable for non-linear laser cutting, and A laser cutting method and apparatus capable of effectively reducing laser cutting processing time.

The traditional glass cutting system uses wheel cutter cutting, but for the rapid development of various industries, especially for the touch panel related industries, the requirements for glass strength are getting higher and higher, which also causes difficulties in traditional round knife glass cutting, such as Corning. The tempered glass produced by (Gorilla glass) is too strong (>120Kgf@1.1mm), which is six times larger than ordinary tempered glass (such as Soda Lime tempered glass). When using traditional wheel cutters for reinforced glass cutting, there will be a wheel cutter. Excessive wear and tear, so there is an urgent need to find alternatives.

Since laser glass cutting is a non-contact cutting method, there is no problem of wheel cutter wear, which can solve the problem of serious wear of the conventional wheel cutter, and has been widely used in high-strength glass cutting in recent years. At present, the common laser cutting method in the industry is to use CO2 laser to cut glass, but most of the cutting methods can only perform linear processing lobes, and it is difficult to process non-linear patterns on the glass, for example, circular, curved or not. Regular arbitrary curve combination. In addition, with short-pulse lasers, although the glass can be directly subjected to destructive processing, and the non-linear pattern is directly processed, it faces the problem of taking too long.

For the known patents, such as the Republic of China Patent Publication No. I270431 "Laser Processing Method", which provides a method of cutting a workpiece, the technical feature of which is to focus on the inside of the workpiece by changing the material properties of the processing zone. The refractive index is changed to make the workpiece easy to cut, and debris can be prevented from being cut off. However, since the case is focused on the inside of the workpiece, it is suitable for straight cutting, and it is difficult to perform circular, curved or not. A non-linear cut of a combination of arbitrary curves.

Secondly, as in U.S. Patent No. 7,605,344, "Laser beam machining method, laser beam machining apparatus, and laser beam machining product", which provides a laser light processing method, which utilizes multiphoton absorption to directly perform destructive processing inside a workpiece to create a cavity. Therefore, it is easier to cut off the target, and the technical feature is that multi-photo absorption is used to form a tiny cavity inside the processed object, and the processing zone is melted and re-solidified. To change its state or change the crystal structure (single crystal, polycrystal, amorphous), the spot pitch is 1-7um, but the processing method provided by the case must use ultrashort pulse laser, Ray The source is expensive.

Secondly, as in Chinese patent CN101663125, "Laser processing method and cutting method and method for dividing a structure having a multi-layer substrate", when scanning a laser while forming a cavity, a small bending stress can be formed thereafter due to the formation of a processing surface. Cutting the workpiece. The method provided by the present invention is applicable to the case where the two substrates are arranged face to face, and can be used for the division of the glass substrate of the liquid crystal panel, and the technical feature thereof is that the ultra-short pulse laser (<100 ps) which is a transparent wavelength of the processed object is collected, from The surface is irradiated to the back surface of the workpiece, and the bottom of the workpiece is subjected to destructive processing to form a hole, and the position of the collected laser waist is spaced apart from the back surface of the workpiece. The material in the channel is decomposed by laser and discharged from the back side of the workpiece, thereby forming a void in the above passage. However, the processing methods provided in this case must use ultra-short pulse lasers, which are expensive and costly to process.

Others, such as the Republic of China Patent Publication No. I250060, "Processing object cutting method using laser, predetermined cutting line forming method, and predetermined cutting line forming device", Japanese Patent JP2007130675 "Laser scribing method", Japanese patent JP2009190069 "Machining method and "device for transparent substrate by laser", the Republic of China patent publication I330170 "method of processing brittle hard materials", all proposed laser cutting related technology.

For published documents, such as the publication "Proc. of SPIE" published on October 25, 2000, "Laser cutting of glass" (author Christoph Hermanns), pp. 219-226, which uses CO2 laser cutting glass And pointed out that when the laser cutting depth <100 um (Micro crack), with the stress changes caused by cooling, the cleavage can achieve a fast cutting speed and better edge quality. However, the full body crack does not require a split, but it takes a long time to process, and a large crack is generated, and the quality is poor.

Secondly, as published in the journal "Journal Of Laser Applications" on October 10, 2008, "Thermal stress analysis on laser scribing of glass" (by Koji Yamamoto, Noboru Hasaka and Hideki Morita and Etsuji Ohmura), pp. 193-200 It is revealed that the thermal stress is generated by the irradiation of the CO2 laser source, and the cooling water is sprayed, the splitting is performed, and the distance between the laser source and the cooling source is analyzed, and the crack edge is changed.

Secondly, as published in the publication "Optics and Lasers in Engineering" on March 25, 2009, "Cutting glass substrates with dual-laser beams" (by Junke Jiao and Xinbing Wang), pages 860-864 reveal low power density The defocused CO2 laser illuminates the glass material without melting or evaporating the glass, but can generate thermal stresses that rise and fall rapidly. And by using a focused CO2 laser to generate a thermal stress change, the glass is cracked as the laser passes through the place.

Secondly, as published in the journal "Mechanical Industry Magazine" on February 13, 2009, the "PD Glass Substrate Laser Cutting Technology Overview" (authors Lin Yuzhong, Cai Weilun), pages 43-55 reveals that more than a dozen companies are different. Laser cutting glass technology, it can be seen that most of the current laser glass cutting technology, still with CO2 laser (higher cost of short pulse laser) with pre-cracking and cooling system, mainly for splitting, with fast speed and The advantages of flattening the section.

In view of the above-mentioned conventional patents and publications, laser cutting technology has been applied to different technical industries, but since most of the laser cutting methods and structures use CO2 lasers, it is difficult to apply in combination with pre-etching cracks. Non-linear processing, and it takes a relatively long time to perform destructive processing on the workpiece. In addition, when the laser light system is focused on the inside of the workpiece, it may be difficult to perform non-linear cutting of a combination of circular, curved or irregular arbitrary curves. Some conventional patents can set the focus position on the bottom surface of the workpiece, but still It is processed in the full cutting manner from the top surface of the workpiece to the bottom surface of the workpiece, and is still destructive. In addition, a small number of laser cuts, although using short-pulse lasers, can be used for non-linear cuts, but they are still destructive and extremely time consuming, for example, cutting a glass with a thickness of 0.7 mm with a 5W UV laser, processing length When it is 50mm, it must be processed at a speed of 100mm/s for four hundred times to cut the glass, and the processing time is at least two hundred seconds.

Therefore, how to have a method and structure suitable for non-linear laser cutting and can effectively reduce the processing time of laser cutting is an important problem that people in the field of laser cutting related art urgently need to solve.

In view of the lack of the prior art, the present invention provides a laser cutting method and apparatus for forming a continuous modified interface from the bottom of the workpiece to the top to perform non-destructive processing on the workpiece, and is suitable for non-linear processing. Laser cutting, and can effectively reduce the laser cutting processing time.

In order to achieve the above object, the present invention provides a laser cutting method for cutting a workpiece, the workpiece having a relative bottom surface and a top surface, and the bottom surface and the top surface are parallel to each other to form the axial direction. The thickness of the workpiece, the laser cutting method comprises: emitting a laser light from a laser source to the workpiece; focusing the laser light on the bottom surface of the workpiece by a lens; and processing the laser light by the laser The bottom surface of the member forms a first modified trajectory; the illumination position of the laser light is changed at least once parallel to the axial direction, so that the laser light forms at least one zoom focus point on the workpiece, and the projection of the at least one zoom focus point Positioning the first modified trajectory; and determining, by the laser light, the at least one zoom focus point, forming at least one zoom modification trajectory, the projection position of the zoom modified trajectory The first modified trajectory overlaps, and the workpiece between the first modified trajectory and the zoom modified trajectory forms a continuous modified interface.

In order to achieve the above object, the present invention further provides a laser cutting device, comprising: a laser source for emitting a laser light; a lens; and a bifocal optical path system disposed on the laser source and the laser source Between the lenses, the bifocal optical path system includes: a beam splitter that provides laser light emitted by the laser source and splits the laser light into a first laser light and a second laser light; a diverging angle mirror group for providing the first laser light incident and changing a divergence angle of the first laser light; a light combining mirror for changing the divergence angle of the first mine via the adjusted divergence angle lens group The light is emitted, and the second laser light is integrated into a laser beam and then directed to the top surface of a workpiece.

In order to enable your review committee to have a better understanding and recognition of the structural purpose and efficacy of the present invention, the detailed description is as follows.

The technical means and efficacy of the present invention for achieving the object will be described below with reference to the accompanying drawings, and the embodiments listed in the following drawings are only for the purpose of explanation, and are to be understood by the reviewing committee, but the technical means of the present invention are not Limited to the listed figures.

Referring to the first figure, a laser cutting device 10 includes a laser source 11, a refractor 12, and a lens 13. The laser source 11 is used to emit a laser beam L, and the laser beam L is directed toward the refraction. After the mirror 12 is refracted toward and through the lens 13, the wavelength of the laser light L is less than 100,000 nm, the energy density of the laser light L is greater than 100 J/cm2, and the lens 13 is a high numerical aperture (NA) lens having a numerical aperture located at Between 0.001 and 1. The laser cutting device 10 is used for cutting a workpiece 20, and the workpiece 20 may be quartz glass, borosilicate glass or various tempered glass. The workpiece 20 has a bottom surface 21 and a top surface 22 on the bottom surface 21 . The thickness t of the workpiece 20 is formed parallel to the axial direction A between the top surface 22, and when the bottom surface 21 of the workpiece 20 is disposed on a plane formed by an X-axis and a Y-axis, the axial direction A is the Z-axis. The Depth of Focus of the laser light L is smaller than the thickness t of the workpiece 20.

Referring to the first to fourth figures, a method 30 for performing laser cutting of the workpiece 20 by the laser cutting device 10 of the first embodiment is illustrated, which includes: Step 31: issuing a laser source 11 After the laser light L, the laser light L is directed toward the refractor 12, it is refracted toward the lens 13 and passes through the lens 13 to be directed toward the top surface 22 of the workpiece 20 in a direction parallel to the axial direction A.

Step 32: The laser light L is focused by the lens 13 on the bottom surface 21 of the workpiece 20, such as the focus point P1 shown in Figs.

Step 33: A first modified trajectory T1 is formed on the bottom surface 21 of the workpiece 20 by the laser light L (as shown in the third figure), and the form of the first modified trajectory T1 is designed according to the shape actually cut. It may be a non-linear shape in which a combination of a circle, an arc or an irregular arbitrary curve is combined. For example, the first modified track T1 formed by a straight line and an arc is formed on the bottom surface 21 of the workpiece 20 as shown in the third figure.

Step 34: After completing the step 33 to form the first modified track T1 on the bottom surface 21 of the workpiece 20, and then changing the irradiation position of the laser light L in a direction parallel to the axial direction A, the laser light L is formed on the workpiece 20. The zoom focus point P2, the zoom focus point P2 is parallel to the projection position of the axial direction A, which is located on the first modified track; as shown in the first figure, the zoom focus point P2 is located inside the workpiece 20, and the zoom focus point P2 is horizontal. The height is higher than the focus point P1, and the zoom focus point P2 is a distance D1 from the focus point P1. By adjusting the relative position of the laser source 11 and the adjustment workpiece 20, the purpose of changing the irradiation position and the focus position of the laser light L can be achieved. For example, when the workpiece 20 is fixed, the irradiation position of the laser light L in the axial direction A is raised to obtain the zoom focus point P2.

Step 35: driving the laser light L to form a zoom modified track T2 on the workpiece 20 with the zoom focus point P2 as a reference, and the projection position of the zoom modified track T2 overlaps with the first modified track T1, and is first modified. A continuous modified interface is formed inside the workpiece 20 between the track T1 and the zoom modified track T2. As shown in the third figure, the first modified track T1 and the zoom modified track T2 form a two-layer modified track. It should be noted that since the laser light L illumination has a range, the laser repetition rate of the irradiation position of the laser light L can be adjusted according to the thickness of the workpiece 20, for example, the laser repetition rate is set to be equal to or less than 50%, so that continuous The modified interface may cover the bottom surface 21 and the top surface 22 of the workpiece 20. When the thickness t of the workpiece 20 is thin, the continuous modified interface formed by the first modified track T1 and the zoom modified track T2 of the embodiment can cover the bottom surface 21 and the top surface 22 of the workpiece 20, if it is processed. When the thickness t of the member 20 is thick, as long as the irradiation position of the laser light L is changed, the laser light L can be formed into other zoom focus points on the workpiece 20, for example, the laser light L can be changed to a different height in the workpiece 20. The first zoom focus point and a second zoom focus point are located inside the workpiece 20, and the second zoom focus point is located on the top surface 22 of the workpiece 20.

The laser cutting method proposed by the present invention is illustrated by the device architecture shown in the first figure. The laser light has a wavelength of 355 nm and a pulse width of less than 30 ns, and is matched with a lens 13 having a numerical aperture of 0.28 at a frequency of 40 kHz and a speed of 200 mm/s. Focusing on a depth of field of 0.035 mm and an energy density of 800 J/cm2, the workpiece 20 is a tempered glass having a thickness of 0.7 mm, first focusing on the bottom surface 21 of the workpiece 20, and the laser light L is formed on the bottom surface 21 of the workpiece 20 at a speed of 200 mm/s. Adjusting the trajectory once, and then adjusting the irradiation position of the laser light L five times in parallel with the axial direction A, each moving distance is 133 μm, and the speed is reduced to 400 times/s to form five modified tracks in the workpiece 20 at a speed of 400 mm/s. The continuous modified interface formed by processing a total of six times can cover the bottom surface 21 and the top surface 22 of the workpiece 20, and since the strength of the workpiece 20 in the continuous reforming interface is reduced, one of the lobes as shown in the first figure can be utilized. The machine 40 assists in the splitting. As shown in the fourth figure, the workpiece 20 can be broken by the position of the continuous modified interface to form the first partial workpiece 20A and the second partial workpiece 20B.

Please refer to the laser cutting device 50 shown in FIG. 5 , which includes a laser source 51 , a lens 53 and a splitter 40 . A dual focus optical path system 52 is provided between the laser source 51 and the lens 53 . The focus optical path system 52 includes a beam splitter 521, a control divergence angle mirror group 522, and a light combining mirror 523. The beam splitter 521 provides laser light L emitted by the laser source 51 to emit light, and splits the laser light L into one. The first laser light L1 and the second laser light L2, the control divergence angle lens group 522 provides the first laser light L1 to enter, and changes the divergence angle of the first laser light L1, and the light combining mirror 523 is used to regulate The divergence angle mirror group 522 changes the first laser light L1 of the divergence angle, and the second laser light L2 is integrated into a laser light L3, and then passes through the lens 53 to the top surface 22 of the workpiece 20, and the laser cutting device 50 The utility model is characterized in that the bifocal optical path system 52 is used to convert the original single focus processing mode into two focus processing modes, thereby improving the process efficiency. As shown in the fifth figure, the focus P3 can be simultaneously formed on the bottom surface 21 and the inside of the workpiece 20. P4.

Please refer to the laser cutting device 60 shown in FIG. 6 , which includes a laser source 61 , a refractor 62 , a lens 63 and a splitter 40 . The laser cutting device 60 is characterized by the lens 63 and the workpiece 20 . A refractive element 64 is disposed between the refractive element 64. The refractive element 64 may be made of quartz glass, borosilicate glass or various tempered glass. The laser light L passes through the refractive element 64 and is then directed to the top surface 22 of the workpiece 20. The laser cutting device 60 is characterized in that the laser beam L passes through the refracting element 64, so that the angle of the ray after the refracting of the air and the refracting element 64 is reduced, so that the focus position of the laser light L can be rapidly changed, and the workpiece 20 can be rapidly formed. Another focus is to improve process efficiency.

In addition, the present invention can also be combined with different device architectures to form a plurality of focus positions on the workpiece to improve process efficiency. Please refer to different embodiments shown in the seventh to tenth diagrams.

Please refer to the laser cutting device 70 shown in FIG. 7 , which includes a laser source 71 , a multi-beam splitting diffractive optical element (DOE) 72 , a lens 73 and a scanning mirror 74 , multi-beam splitting diffracting optics The component (DOE) 72 may be provided as a single piece or a plurality of pieces, which are separated into a plurality of channels by a single or multiple pieces of multi-beam splitting diffractive optical element (DOE) 72, and the laser light L emitted by the laser source 71 is divided into multiple channels. After the light L4, the laser light L4 is transmitted through the lens 73 and the scanning mirror 74, a plurality of laser light L5 can be formed to form a plurality of focusing points on a single plane of the workpiece 20.

Please refer to the laser cutting device 80 shown in the eighth figure, which mainly includes a laser source 81 and a progressive multifocal lens 82. Referring to the ninth figure, the progressive addition lens 82 has different focus areas 821-824. Thereby, the laser beam L emitted from the laser source 81 can be divided into the plurality of laser beams L6 through the progressive multifocal lens 82, so that a plurality of focus positions can be formed in the workpiece (not shown).

Please refer to the laser cutting device 90 shown in FIG. 10, which mainly includes a laser source 91, a plurality of beam splitters 92A-92C, and a plurality of lenses 93A-93C, which are transmitted through a plurality of beam splitters 92A-92C and a plurality of The lenses 93A to 93C can divide the laser light L emitted from the laser source 91 into a plurality of laser beams L7A to L7C, so that a plurality of focus positions can be formed in the workpiece (not shown).

In summary, the laser cutting method provided by the present invention is formed by the bottom of the workpiece rising to the top to form a continuous modified interface, and the non-destructive processing of the workpiece is not only suitable for non-linear laser cutting, and The laser cutting processing time can be effectively reduced. For example, the glass having a thickness of 0.7 mm is cut and the processing length is 50 mm. For example, the method and the device provided by the present invention are used for cutting, and the 5W UV laser is used for a 200 mm/s. Five times 400mm / s speed, a total of six times, you can cut the glass, it takes less than a second, compared to the traditional processing of 5W UV laser and 100mm / s speed four hundred times, at least It takes two hundred seconds to cut the glass. The invention can increase the processing speed by at least two hundred times, which is beneficial to the industrial manufacturing process, shortening the processing time and increasing the manufacturing speed. Incidentally, in the laser cutting method provided by the present invention, the required laser light and the specifications of the lens must be set according to the material and thickness of the workpiece to be cut, and verified by experiments, if the laser light has a frequency of 40 KHz, the speed When the energy density is less than 1 mm/s and the energy density is more than 2000 J/cm ² , the surface of the workpiece is easily damaged, and the modified region cannot be formed on the bottom surface of the machined surface. Further, if a lens having an F value (focal length) of 100 mm is used, When the depth of focus is 0.886 mm, the modified region cannot be formed on the bottom surface of the workpiece having a thickness of 0.7 mm.

However, the above description is only for the embodiments of the present invention, and the scope of the invention is not limited thereto. That is to say, the equivalent changes and modifications made by the applicant in accordance with the scope of the patent application of the present invention should still fall within the scope of the patent of the present invention. I would like to ask your review committee to give a clear explanation and pray for it.

10, 50, 60, 70, 80, 90. . . Laser cutting device

11, 51, 61, 71, 81, 91. . . Laser source

12, 62. . . Refracting mirror

13, 53, 63, 73, 93A~93C. . . lens

20. . . Machined parts

20A. . . The first part of the workpiece

20B. . . Second part of the workpiece

twenty one. . . Bottom

twenty two. . . Top surface

30. . . Laser cutting method flow

31~35. . . step

40. . . Splitter

52. . . Bifocal optical path system

521, 92A~92C. . . Beam splitter

522. . . Regulating divergent horn group

523. . . Light mirror

64. . . Refractive element

72. . . Multi-beam splitting diffractive optical element (DOE)

74. . . Scanning mirror

82. . . Progressive multifocal lens

A. . . Axial

D1. . . distance

L. . . laser

L1. . . First laser light

L2. . . Second laser light

L3, L4, L5, L6, L7A, L7B, L7C. . . laser

P1. . . Focus point

P2. . . Zoom focus point

P3, P4. . . focus

T1. . . First modification track

T2. . . Zoom modification track

t. . . thickness

The first figure is a schematic diagram of the structure of a laser cutting device for performing the laser cutting method of the present invention.

The second figure is a flow chart of the laser cutting method of the present invention.

The third figure is a schematic diagram of the laser cutting method of the present invention forming different modified tracks on the workpiece.

The fourth figure is a schematic diagram of the fracture of the workpiece from the continuous modified interface.

The fifth and sixth figures are schematic diagrams of the architecture of different laser cutting devices for performing the laser cutting method of the present invention.

7 to 11 are schematic views showing the structure of different device embodiments in which the laser cutting method of the present invention is formed by forming a plurality of focus positions on a workpiece.

30. . . Laser cutting method flow

31~35. . . step

Claims (13)

A laser cutting method for cutting a workpiece having a relative bottom surface and a top surface, the laser cutting method comprising: emitting a laser light from a laser source to the workpiece; a lens for focusing the laser light on the bottom surface of the processing member; forming, by the laser light, a first modified trajectory on the bottom surface of the processing member; at least changing the irradiation position of the laser light to make the laser light Forming at least one zoom focus point, the projection position of the at least one zoom focus point is on the first modified track; and the laser light forms at least one on the workpiece according to the at least one zoom focus point The zoom modification track, the projection position of the zoom modified track overlaps with the first modified track, and the workpiece between the first modified track and the zoom modified track forms a continuous modified interface. The laser cutting method of claim 1, wherein the laser light has a depth of focus (Depth of Focus) which is smaller than the thickness of the workpiece. The laser cutting method of claim 1, wherein the laser light has an energy fluence greater than 100 J/cm 2 . The laser cutting method of claim 1, wherein the lens is a high numerical aperture (NA) lens having a numerical aperture between 0.001 and 1. The laser cutting method according to claim 1, wherein the laser light is changed once, so that the laser light forms a first zoom focus point on the workpiece, and the first zoom focus point is located. The inside of the workpiece between the bottom surface of the workpiece and the top surface. The laser cutting method of claim 1, wherein the laser light is changed to a position where the laser light is irradiated to form a first zoom focus point and a second zoom focus point. The first zoom focus is located inside the workpiece, and the second zoom focus is located on the top surface of the workpiece. The laser cutting method according to claim 1, wherein the laser light irradiation position has a laser repetition rate of 50% or less. The laser cutting method of claim 1, wherein the laser light has a wavelength of less than 100,000 nm. The laser cutting method of claim 1, wherein a refractive element is disposed between the lens and the workpiece, and the laser light passes through the refractive element and then is directed to the top surface of the workpiece. To quickly form another focus. The laser cutting method according to claim 1, wherein the laser light emitted by the laser source is split into multiple laser beams by a single or multiple multi-beam splitting diffractive optical element (DOE). And then, through the lens, a plurality of focusing points are formed on a single plane of the workpiece. The laser cutting method according to claim 1, wherein the laser beam emitted from the laser source is formed into a plurality of focus positions by the progressive multifocal lens. The laser cutting method according to claim 1, wherein the plurality of beamsplitters and the plurality of lenses are transmitted through the plurality of lenses, and the laser light emitted from the laser source forms a plurality of focus positions on the workpiece. A laser cutting device comprising: a laser source for emitting a laser beam; a lens; and a bifocal optical path system disposed between the laser source and the lens, the bifocal optical path system comprising a spectroscope for providing the laser light emitted by the laser source and splitting the laser light into a first laser light and a second laser light; and a control divergence angle lens group a laser light is incident and changes a divergence angle of the first laser light; a light combining mirror is configured to convert the first laser light having a divergence angle through the adjusted divergence angle lens group, and the second laser light integration After a laser beam, it is directed to the top surface of a workpiece.