Laser forming of non-square edges in transparent workpieces using modified airy beams

Abstract

A method includes directing a laser beam onto a phase adjustment device such that the laser beam downstream of the phase adjustment device is a modified Airy beam having a modified Airy beam focal region with a main lobe and a plurality of side lobes. The main lobe has a lobe aspect ratio of 1.2 or greater.

Description

[0001] This application claims priority to Dutch Patent Application Serial No. 2026552, filed on September 28, 2020, which claims priority to U.S. Provisional Patent Application Serial No. 63 / 077,200, filed on September 11, 2020, the contents of which are incorporated herein by reference in their entirety. background Technical Field

[0003] This application relates to glass processing, and more specifically, to systems and methods for processing glass substrates using a modified Airy beam. Background Technology

[0005] Glass processing, including glass cutting (splitting) and edge finishing, is crucial in the formation of glass products such as display glass, glass panels, and cover glass. In particular, the square edges of glass sheets are prone to breakage and can therefore be processed to have bevels or be rounded to minimize the likelihood of breakage. This processing can be achieved using mechanical means such as mechanical grinding. Similarly, glass substrates need to be cut to selected dimensions and shapes. This processing can also be achieved using mechanical means such as diamond saw blades. Unfortunately, machining glass substrates is complex and generates glass dust and particles that must be removed.

[0006] As an alternative, conventional laser processing can be used instead of machining to perform cutting and edge finishing operations. However, conventional laser processing utilizes a laser beam that travels in a straight line in free space, making it difficult to use when rounded outer edges or similar edge shaping are desired. Summary of the Invention

[0007] According to a first aspect of this disclosure, a method includes: directing a laser beam to a phase adjustment device such that the laser beam downstream of the phase adjustment device is a modified Airy beam having a modified Airy beam focusing region having a main lobe and a plurality of side lobes, wherein the main lobe has a beam aspect ratio of 1.2 or greater.

[0008] The second aspect of this disclosure includes the method of the first aspect, wherein the aspect ratio of the main lobe is 1.5 or greater.

[0009] The third aspect of this disclosure includes the method of the first or second aspect, wherein the aspect ratio of the main lobe is 2 or greater.

[0010] The fourth aspect of this disclosure includes the method of any of the foregoing aspects, wherein the aspect ratio of the main lobe is 3 or greater.

[0011] The fifth aspect of this disclosure includes a method of any of the foregoing aspects, wherein at least 60% of the laser energy of the modified Airy beam focusing region is set in the main lobe.

[0012] The sixth aspect of this disclosure includes a method of any of the foregoing aspects, wherein at least 65% of the laser energy of the modified Airy beam focusing region is set in the main lobe.

[0013] The seventh aspect of this disclosure includes a method of any of the foregoing aspects, wherein at least 68% of the laser energy of the modified Airy beam focusing region is set in the main lobe.

[0014] The eighth aspect of this disclosure includes a method of any of the foregoing aspects, wherein the phase adjustment device includes a phase plate having cubic phase modulation.

[0015] The ninth aspect of this disclosure includes a method of any of the foregoing aspects, wherein the phase adjustment device includes a phase modulation function. Where α is the phase modulation frequency. Where λ is the wavelength of the laser beam, x and y are the spatial coordinates of the phase adjustment device, and α y It is the phase modulation frequency ratio, and α y It is 0.8 or smaller.

[0016] The tenth aspect of this disclosure includes the method of the ninth aspect, wherein α y It is 0.6 or smaller.

[0017] The eleventh aspect of this disclosure includes a method of any of the foregoing aspects, wherein the laser beam is a pulsed laser beam having pulse trains, and each pulse train of the pulsed laser beam has 2 to 20 sub-pulses.

[0018] The twelfth aspect of this disclosure includes a method of any of the foregoing aspects, further comprising: guiding a modified Airy beam onto a transparent workpiece such that the modified Airy beam forms a modified Airy beam focusing region in the transparent workpiece, the modified Airy beam focusing region inducing absorption in the transparent workpiece, and the induced absorption generating a bending defect in the transparent workpiece.

[0019] The thirteenth aspect of this disclosure includes the method of the twelfth aspect, further comprising: translating at least one of the transparent workpiece and the modified Airy beam relative to each other along a contour line to form a contour having multiple bending defects.

[0020] The fourteenth aspect of this disclosure includes the method of the thirteenth aspect, wherein the interval between adjacent bending defects in a plurality of bending defects is 35 μm or less.

[0021] The fifteenth aspect of this disclosure includes the method of the thirteenth or fourteenth aspect, further comprising: applying stress to a contour to separate a transparent workpiece along the contour, thereby forming a non-square edge on the transparent workpiece.

[0022] The sixteenth aspect of this disclosure includes the method of any one of aspects twelfth to fifteenth, wherein the transparent workpiece is borosilicate glass, soda-lime glass, aluminosilicate glass, alkali metal aluminosilicate glass, alkaline earth metal aluminosilicate glass, alkaline earth metal borosilicate glass, fused silica, sapphire, silicon, or gallium arsenide.

[0023] According to the seventeenth aspect of this disclosure, a method includes: directing a laser beam output from a beam source onto a beamforming element such that a laser beam downstream of the beamforming element includes a modified laser beam having an asymmetric cross-sectional shape; and directing the modified laser beam onto a phase adjustment device such that the modified laser beam projects an asymmetric beam spot onto the phase adjustment device, and the modified laser beam downstream of the phase adjustment device is a modified Airy beam, wherein the asymmetric beam spot has a beam spot aspect ratio of 1.5 or greater.

[0024] The eighteenth aspect of this disclosure includes the method of the seventeenth aspect, wherein the modified Airy beam includes a modified Airy beam focusing region having a main lobe and a plurality of side lobes, and at least 59% of the laser energy of the modified Airy beam focusing region is set on the main lobe.

[0025] The nineteenth aspect of this disclosure includes the method of the seventeenth or eighteenth aspect, wherein the modified Airy beam includes a modified Airy beam focusing region having a main lobe and a plurality of side lobes, and at least 65% of the laser energy of the modified Airy beam focusing region is set on the main lobe.

[0026] The twentieth aspect of this disclosure includes the method of any one of the seventeenth to nineteenth aspects, wherein the aspect ratio of the beam spot is 3.0 or greater.

[0027] The twentieth aspect of this disclosure includes the method of any one of the seventeenth to twentieth aspects, wherein the aspect ratio of the beam spot is 4.0 or greater.

[0028] The 22nd aspect of this disclosure includes a method of any one of the 17th to 21st aspects, wherein the phase adjustment device includes a phase plate having cubic phase modulation.

[0029] The twenty-third aspect of this disclosure includes a method of any one of aspects seventeen to twenty-two, wherein the phase adjustment device includes a phase modulation function. Where α is the phase modulation frequency. Where λ is the wavelength of the laser beam, x and y are the spatial coordinates of the phase adjustment device, and α y It is the phase modulation frequency ratio, and α y It is 0.8 or smaller.

[0030] The twentieth aspect of this disclosure includes the method of the twentieth aspect, wherein α y It is 0.6 or smaller.

[0031] The 25th aspect of this disclosure includes the method of any one of the 17th to 24th aspects, wherein the beamforming element includes one or more refractive optical elements, diffractive optical elements, or combinations thereof.

[0032] The 26th aspect of this disclosure includes the method of any one of the 17th to 25th aspects, wherein the modified Airy beam focusing region includes a main lobe and a plurality of side lobes, and the main lobe includes a beam aspect ratio of 1.5 or greater.

[0033] The twentieth aspect of this disclosure includes the method of any one of the seventeenth to twenty-sixth aspects, wherein the modified Airy beam focusing region includes a main lobe and a plurality of side lobes, and the main lobe includes a beam aspect ratio of 2 or greater.

[0034] The twentieth aspect of this disclosure includes the method of any one of the seventeenth to twenty-seventh aspects, wherein the modified Airy beam focusing region includes a main lobe and multiple side lobes, and the main lobe includes a beam aspect ratio of 3 or greater.

[0035] The 29th aspect of this disclosure includes the method of any one of aspects 17 to 28, further comprising: guiding a modified Airy beam onto a transparent workpiece such that the modified Airy beam forms a modified Airy beam focusing region in the transparent workpiece, the modified Airy beam focusing region inducing absorption in the transparent workpiece, and the induced absorption generating a bending defect in the transparent workpiece.

[0036] The thirtieth aspect of this disclosure includes the method of the twenty-ninth aspect, further comprising: translating at least one of the transparent workpiece and the modified Airy beam relative to each other along a contour line to form a contour having multiple bending defects.

[0037] The thirty-first aspect of this disclosure includes the method of the thirtieth aspect, wherein the interval between adjacent bending defects in a plurality of bending defects is 35 μm or less.

[0038] The thirty-second aspect of this disclosure includes the method of the thirty-first aspect, further comprising: applying stress to a contour to separate a transparent workpiece along the contour, thereby forming a non-square edge on the transparent workpiece.

[0039] The thirty-third aspect of this disclosure includes a method of any one of the thirty to thirty-second aspects, wherein a plurality of bending defects include a central defect region and one or more radial arms extending outward from the central defect region along a contour line.

[0040] The thirty-fourth aspect of this disclosure includes the method of the thirty-third aspect, wherein the modified Airy beam focusing region comprises a main lobe and a plurality of side lobes, wherein the main lobe is asymmetric, having a horizontal lobe axis, a vertical lobe axis, and a lobe aspect ratio of 1.2 or greater; and when the modified Airy beam focusing region induces absorption in a transparent workpiece to form each bending defect, the horizontal lobe axis of the main lobe of the modified Airy beam focusing region is aligned with at least one radial arm of the bending defect.

[0041] The thirty-fifth aspect of this disclosure includes the method of any one of the seventeenth to thirty-fourth aspects, wherein the laser beam is a pulsed laser beam having pulse trains, and each pulse train of the pulsed laser includes 2 to 20 sub-pulses.

[0042] According to the thirty-sixth aspect of this disclosure, a modified Airy beam includes a modified Airy beam focusing region having a main lobe and a plurality of side lobes, wherein the main lobe has a beam aspect ratio of 1.2 or greater.

[0043] The thirty-seventh aspect of this disclosure includes a modified Airy beam of the thirty-sixth aspect, wherein the aspect ratio of the main lobe is 1.5 or greater.

[0044] The thirty-eighth aspect of this disclosure includes a modified Airy beam of the thirty-sixth or thirty-seventh aspect, wherein the aspect ratio of the main lobe is 2 or greater.

[0045] The thirty-ninth aspect of this disclosure includes a modified Airy beam of any of the thirty-sixth to thirty-eighth aspects, wherein the aspect ratio of the main lobe is 3 or greater.

[0046] The fortieth aspect of this disclosure includes a modified Airy beam of any of the thirty-sixth to thirty-ninth aspects, wherein the aspect ratio of the main lobe is 4 or greater.

[0047] The forty-first aspect of this disclosure includes a modified Airy beam according to any one of the thirty-sixth to fortyth aspects, wherein at least 60% of the laser energy of the focused region of the modified Airy beam is set in the main lobe.

[0048] The forty-second aspect of this disclosure includes a modified Airy beam of any of the thirty-sixth to forty-first aspects, wherein at least 65% of the laser energy of the focused region of the modified Airy beam is set in the main lobe.

[0049] The forty-third aspect of this disclosure includes a modified Airy beam of any of the thirty-sixth to forty-second aspects, wherein at least 68% of the laser energy of the focused region of the modified Airy beam is set in the main lobe.

[0050] Additional features and advantages of the processes and systems described herein will be set forth in the following detailed description and will become apparent in part to those skilled in the art from the description, or may be recognized by practice of the embodiments described herein (including the detailed description below and the accompanying drawings).

[0051] It should be understood that both the above general description and the following detailed description depict various embodiments, and they are intended to provide an overview or framework for understanding the nature and characteristics of the claimed subject matter. The accompanying drawings are included to provide a further understanding of the various embodiments, and are incorporated into and form a part of this specification. The drawings illustrate the various embodiments described herein and, together with the description, serve to illustrate the principles and operation of the claimed subject matter. Attached Figure Description

[0052] The embodiments illustrated in the accompanying drawings are illustrative and exemplary in nature and are not intended to limit the subject matter defined herein. The following detailed description of the illustrative embodiments will be understood when read in conjunction with the following drawings, wherein similar reference numerals indicate similar structures, and wherein:

[0053] Figure 1A An example optical system according to one or more embodiments shown and described herein is schematically depicted, the example optical system including a phase adjustment device for forming an Airy beam and processing a transparent workpiece using the Airy beam;

[0054] Figure 1B The illustration schematically depicts one or more embodiments shown and described herein. Figure 1A Phase contour map of the phase adjustment device;

[0055] Figure 1C The use of one or more embodiments shown and described herein is illustrated schematically. Figure 1A The optical system forms the Airy beam focusing area;

[0056] Figure 1D The illustration schematically depicts one or more embodiments shown and described herein. Figure 1CThe beam cross-section of the Airy beam local focusing region;

[0057] Figure 2A The formation of the outline of a bending defect in a transparent workpiece according to one or more embodiments shown and described herein is schematically depicted;

[0058] Figure 2B The illustration schematically depicts one or more embodiments shown and described herein. Figure 2A A transparent workpiece having a non-square edge formed after the contour separation of a bending defect;

[0059] Figure 3A An example optical system according to one or more embodiments shown and described herein is schematically depicted, the example optical system including a modified phase adjustment device for forming a modified Airy beam and processing a transparent workpiece using the modified Airy beam;

[0060] Figure 3B The illustration schematically depicts one or more embodiments shown and described herein. Figure 3A The example modified phase adjustment device has a phase contour plot with a phase modulation frequency ratio α of 0.8. y ;

[0061] Figure 3C The use of one or more embodiments shown and described herein is illustrated schematically. Figure 3B The beam cross-section of the Airy beam local focusing region formed by an exemplary modified phase adjustment device;

[0062] Figure 3D The illustration schematically depicts one or more embodiments shown and described herein. Figure 3A The example modified phase adjustment device has a phase contour plot with a phase modulation frequency ratio α of 0.6. y ;

[0063] Figure 3E The use of one or more embodiments shown and described herein is illustrated schematically. Figure 3D The beam cross-section of the Airy beam local focusing region formed by an exemplary modified phase adjustment device;

[0064] Figure 4A An exemplary optical system according to one or more embodiments shown and described herein is schematically depicted, the exemplary optical system including Figure 1A Phase adjustment equipment and shape adjustment equipment for forming a modified Airy beam and processing transparent workpieces using the modified Airy beam;

[0065] Figure 4B The illustration schematically depicts one or more embodiments shown and described herein. Figure 4A The phase contour map of the phase adjustment device, with asymmetrical beam spots superimposed on it;

[0066] Figure 4C The illustration schematically depicts an impact by an elliptical beam spot according to one or more embodiments shown and described herein. Figure 4B A portion of the phase contour map;

[0067] Figure 5A The use of exemplary asymmetric beam patterns and... is schematically depicted according to one or more embodiments shown and described herein. Figure 1A The beam cross-section of the Airy beam focusing area formed by the phase adjustment device;

[0068] Figure 5B The use of another exemplary asymmetric beam pattern and according to one or more embodiments shown and described herein is illustrated schematically. Figure 1A The beam cross-section of the Airy beam focusing area formed by the phase adjustment device;

[0069] Figure 6A It is based on one or more embodiments shown and described herein, using Figure 1A A top view of an exemplary profile of a bending defect formed in a transparent workpiece by an optical component;

[0070] Figure 6B It is based on one or more embodiments shown and described herein. Figure 6A A side view of an exemplary contour of a bending defect;

[0071] Figure 7A It is based on one or more embodiments shown and described herein, using Figure 4A A top view of an exemplary profile of a bending defect formed in a transparent workpiece by an optical component;

[0072] Figure 7B It is based on one or more embodiments shown and described herein. Figure 7A A side view of an exemplary contour of a bending defect;

[0073] Figure 8A This is a side view of an exemplary non-square edge including a bullnose shape formed in a transparent workpiece using the laser processing method of this disclosure according to one or more embodiments shown and described herein;

[0074] Figure 8B It is based on one or more embodiments shown and described herein. Figure 8AA front view including an exemplary non-square edge in the shape of a bull's nose; and

[0075] Figure 9 This is a side view of an exemplary non-square edge, including an inverted bullnose shape, formed in a transparent workpiece using the laser processing method of this disclosure according to one or more embodiments shown and described herein. Detailed Implementation

[0076] Separation and edge finishing play a crucial role in many products formed from transparent workpieces, such as glass products like display glass and cover glass. Specifically, transparent workpieces with square edges are prone to breakage propagating from these edges. Therefore, square edges are often processed to form non-square edges, such as rounded edges, beveled edges, etc., to minimize the possibility of breakage. Currently, non-square edges are typically formed using mechanical means such as mechanical grinding and polishing. However, these machining processes generate glass dust and particles, which must be cleaned through additional process steps involving washing or chemical treatment. Therefore, it is desirable to replace traditional edge finishing processes with a particle-free and high-throughput process for forming non-square edges. Laser processing using Airy beams with self-bending properties offers a solution for forming particle-free and high-throughput processing of non-square edges.

[0077] The optical systems and methods described herein utilize Airy beams with self-bending properties to provide a high-throughput process for forming non-square edges with minimal particle generation and undesirable damage. Specifically, the optical systems and methods described herein use modified Airy beams to form bending defects in transparent workpieces to minimize accidental damage to the transparent workpiece and facilitate efficient separation with minimal roughness on the resulting non-square edges. The modified Airy beams described herein concentrate a larger percentage of laser energy in the main lobe than unmodified Airy beams. For example, in an unmodified Airy beam, approximately 50% of the laser energy can be concentrated in the main lobe, while in the modified Airy beams described herein, approximately 68% of the laser energy can be concentrated in the main lobe. Since the main lobe is the portion of the Airy beam used to modify the transparent workpiece (e.g., the portion of the Airy beam focusing region), increasing the percentage of laser power concentrated in the main lobe increases the efficiency of laser processing and improves processing throughput. Reference will now be made in detail to various embodiments of this disclosure, examples of which are illustrated in the accompanying drawings. Whenever possible, use the same or similar reference numerals and symbols in all accompanying drawings to refer to the same or similar parts.

[0078] While not intended to be theoretically limited, an "Airy beam" is a type of laser beam that incorporates curvature in free space due to the selective phase of the beam. An Airy beam can be formed by guiding a conventional Gaussian laser beam through a phase-adjusting device, such as a phase plate, which increases the depth of focus and alters the beam's propagation trajectory. In some embodiments, an Airy beam may be referred to as a self-bending beam, an accelerating beam, a self-accelerating beam, or a non-diffractive beam. The cross-section of an Airy beam (i.e., a cross-section orthogonal to the beam's propagation trajectory) comprises multiple lobes, including a main lobe and multiple side lobes. The main lobe is the largest lobe and has the highest energy. When an Airy beam is used during a transparent workpiece separation process, non-square edges can be formed due to the curvature of the Airy beam, and the energy in the main lobe is used to modify the transparent workpiece (e.g., ablate, form defects, or otherwise alter it to facilitate separation).

[0079] As used herein, “laser processing” includes directing a laser beam onto and / or into a transparent workpiece. In some embodiments, laser processing further includes translating the laser beam relative to the transparent workpiece, for example, along a contour or other path. Examples of laser processing include forming a contour using an Airy beam that includes a series of curved defects extending into the transparent workpiece. The transparent workpiece can be separated along the contour including the series of curved defects by additional laser processes, such as by using an infrared laser beam.

[0080] As used herein, “upstream” and “downstream” refer to the relative positions of two locations or components along the beam path relative to the beam source. For example, if a first component is closer to the laser source along the path traversed by the laser beam than a second component, then the first component is upstream of the second component.

[0081] As used herein, a “profile” corresponds to a set of intersection points between the laser beam and the incident surface of the transparent workpiece, resulting from the relative motion between the laser beam and the transparent workpiece. The profile can be linear, angled, polygonal, or curved. The profile can be closed (i.e., defining a closed region on the surface of the substrate) or open (i.e., not defining a closed region on the surface of the substrate). The profile represents a boundary along which separation of the substrate into two or more parts is facilitated.

[0082] As used herein, a “profile” refers to a set of defects (e.g., bending defects) formed in a transparent workpiece by the relative movement of a laser beam with the substrate along the profile. The defects are spaced apart along the profile and are either entirely contained within the transparent workpiece or extend into the transparent workpiece through one or more surfaces. Defects can also extend across the entire thickness of the transparent workpiece. Separation of the transparent workpiece occurs through connecting defects (such as, for example, through the propagation of cracks).

[0083] As used herein, a “defect” refers to a region of a transparent workpiece that has been modified by a laser beam. Since the defects described herein are formed by an Airy beam with self-bending properties, the defects bend relative to the curve of the Airy beam and are therefore referred to hereinafter as “bending defects.” Bending defects include regions of a transparent workpiece with a modified refractive index relative to the surrounding unmodified region of the transparent workpiece. Bending defects can include structurally modified regions in a transparent workpiece produced by an Airy beam, such as voids, cracks, scratches, blemishes, holes, perforations, densification, or other deformations. Bending defects are formed through the interaction between the Airy beam (specifically, the main lobe of the Airy beam) and the transparent workpiece. As described more fully below, the Airy beam is generated by a pulsed laser. Bending defects at specific locations along a contour are formed by the main lobe of an Airy beam generated by a single laser pulse at that specific location, a pulse train of subpulses at that specific location, or multiple laser pulses at that specific location. The relative motion of the laser beam and the transparent workpiece along the contour results in multiple bending defects forming the contour.

[0084] As used herein, the phrase "transparent workpiece" refers to a workpiece formed of glass, glass-ceramic, or other transparent materials, wherein the term "transparent" as used herein means that the material has less than 20% linear optical absorption per millimeter of material depth, such as less than 10% per millimeter of material depth for a specified pulsed laser wavelength, or less than 1% per millimeter of material depth for a specified pulsed laser wavelength. Unless otherwise specified, the material has less than about 20% linear optical absorption per millimeter of material depth. Transparent workpieces may have a depth (e.g., thickness) from about 50 micrometers (μm) to about 10 mm (such as from about 100 μm to about 5 mm, or from about 0.5 mm to about 3 mm). Transparent workpieces may include glass workpieces formed of glass compositions such as borosilicate glass, soda-lime glass, aluminosilicate glass, alkali metal aluminosilicate, alkaline earth metal aluminosilicate glass, alkaline earth metal borosilicate glass, fused silica, or crystalline materials (such as sapphire, silicon, gallium arsenide), or combinations thereof. In some embodiments, the transparent workpiece may be strengthened by heat tempering before or after laser processing. In some embodiments, the glass may be ion-exchangeable, such that the glass composition may undergo ion exchange to achieve glass strengthening before or after laser processing of the transparent workpiece. For example, the transparent workpiece may include ion-exchangeable glass and ion-exchangeable glass, such as Corning glass available from Corning Incorporated, Corning, New York. (Corning (e.g., Nos. 2318, 2319, and 2320) glass. Furthermore, these ion-exchange glasses may have a coefficient of thermal expansion (CTE) ranging from about 6 ppm / °C to about 10 ppm / °C. Other example transparent workpieces may include EAGLE, available from Corning Incorporated, Corning, NY. And Corning Lotus TM In addition, transparent workpieces may include other components that are transparent to the wavelength of lasers, such as glass ceramics or crystals such as sapphire or zinc selenide.

[0085] In an ion exchange process, ions in the surface layer of a transparent workpiece are replaced by larger ions with the same valence or oxidation state, for example, by immersing the transparent workpiece partially or completely in an ion exchange bath. Replacing smaller ions with larger ions extends a compressive stress layer from one or more surfaces of the transparent workpiece to a certain depth within the workpiece, known as the layer depth. The compressive stress is balanced by a tensile stress layer (called central tension), resulting in zero net stress in the glass sheet. The compressive stress formed at the surface of the glass sheet strengthens the glass and resists mechanical damage, thus mitigating catastrophic failures caused by defects that do not extend through the layer depth. In some embodiments, smaller sodium ions in the surface layer of the transparent workpiece are exchanged for larger potassium ions. In some embodiments, the ions in the surface layer and the larger ions are monovalent alkali metal cations, such as Li+ (when present in the glass), Na+, K+, Rb+, and Cs+. Alternatively, the monovalent cations in the surface layer can be replaced by monovalent cations other than alkali metal cations (such as Ag+, Tl+, Cu+, etc.).

[0086] Now for reference Figure 1A The image depicts an optical system 100 for laser processing of a transparent workpiece 160. The transparent workpiece 160 includes a first surface 162, a second surface 164 opposite to the first surface 162, and one or more edges 166. Figure 1A As shown, edge 166 is a square edge. Optical system 100 is configured to convert a laser beam 112 (e.g., a Gaussian laser beam) into a phase-adjusted laser beam 212, which, when focused using focusing lens 130, forms an Airy beam 312 focused into the Airy beam focusing region 313. The Airy beam 312 can be used to form a series of bending defects 172 in a transparent workpiece 160. Figure 2A The transparent workpiece 160 can be separated along the series of bending defects 172 to form one or more non-square edges 168. Figure 2B ).

[0087] Optical system 100 includes a beam source 110 that emits a laser beam 112, which may include a Gaussian laser beam. Without being theoretically constrained, the Gaussian beam monotonically decays and its diameter is typically 1 / e of the maximum intensity of the Gaussian beam. 2 The intensity decrease is used to define the intensity. In some embodiments, the laser beam 112 emitted by the beam source 110 is pulsed and comprises short optical pulses (e.g., in the femtosecond to picosecond range) or pulse trains of a series of closely spaced sub-pulses. In some embodiments, the beam source 110 may output a laser beam 112 with wavelengths including, for example, 1064 nm, 1030 nm, 532 nm, 530 nm, 355 nm, 343 nm, or 266 nm, or 215 nm. Furthermore, the laser beam 112 converted to Airy beam 312 and used to form a bending defect 172 in a transparent workpiece 160 is well suited to materials transparent to the selected laser wavelength. A suitable laser wavelength for forming the bending defect 172 is one at which the combined loss of linear absorption and scattering of the transparent workpiece 160 is sufficiently low.

[0088] Still referencing Figure 1A The optical system 100 further includes a phase adjustment device 120 positioned downstream of the beam source 110, such that a laser beam 112 (e.g., a pulsed laser beam) emitted by the beam source 110 impacts (e.g., passes through or is reflected from) the phase adjustment device 120 and then passes through the focusing lens 130. The phase adjustment device 120 is configured to adjust the phase of the laser beam 112 to form a phase-adjusted laser beam 212. Specifically, the phase adjustment device 120 adds cubic phase modulation to the laser beam 112 to form a phase-adjusted laser beam 212 downstream of the phase adjustment device 120. The cubic phase modulation used to form the phase-adjusted laser beam 212 is such that, when the phase-adjusted laser beam 212 is focused by the focusing lens 130, the phase-adjusted laser beam 212 forms an Airy beam 312 focused in an Airy beam focusing region 313 near the focal point FP of the focusing lens 130. Without being bound by theory, the phase-adjusted laser beam 212 is a laser beam with a cubic phase, and the Airy beam 312 is a Fourier transform of a cubic phase, wherein the focusing lens 130 causes the Fourier transform.

[0089] Now for reference Figure 1A and Figure 1B The phase function of the Airy beam can be expressed by equation (1) as follows:

[0090]

[0091] in It is the phase, and α is the frequency of phase modulation. Furthermore, x and y are the wave vector of the laser beam 112, and x and y are the spatial coordinates of the phase function. Specifically, Figure 1B A phase adjustment device 120 is shown for ultimately forming an Airy beam 312 and an Airy beam focusing region 313 downstream of a focusing lens 130 using a cubic phase mask 121. In some embodiments, the phase adjustment device 120 includes diffractive optical elements, such as a phase plate (which may be an Airy phase plate or an Airy phase mask) pre-fabricated on an optical surface with cubic phase modulation, and in other embodiments; the phase adjustment device 120 includes a spatial light modulator comprising a large number of pixels with an adjustable refractive index. In embodiments where the phase adjustment device 120 includes a phase plate, the cubic phase mask 121 corresponds to the surface topography of the phase plate. The phase adjustment device 120 may be transmissive or reflective. For example, the phase plate embodiment of the phase adjustment device 120 may be transmissive, and the spatial light modulator embodiment of the phase adjustment device 120 may be reflective. Furthermore, embodiments are conceived in which the phase adjustment device 120 includes a spatial light modulator having both a lens phase and a cubic phase or a diffraction cubic phase, such that an Airy beam 312 is formed directly downstream of the spatial light modulator without the need for a focusing lens 130.

[0092] exist Figure 1C and Figure 1D The image shows the Airy beam focusing region 313 of the representative Airy beam 312 in more detail. Due to the cubic nature of the phase of the Airy beam 312, it exhibits a curved trajectory when focused by the focusing lens 130. In fact, Figure 1C The curved beam path of the Airy beam focusing region 313 is depicted, which is the Airy beam 312 near the focal point FP of the focusing lens 130. The portion of the Airy beam focusing region 313 with the highest intensity is the main lobe 315 (see...). Figure 1D ), which corresponds to Figure 1A and Figure 1C The curved portion is shown in the diagram. Furthermore, the Airy beam focusing region 313 further includes multiple side lobes 316, each of which has a lower intensity than the main lobe 315. Figure 1C and Figure 1D The side lobe 316 corresponds to the one from Figure 1A The curved portion of the Airy beam focusing region 313 is offset by intersecting rays. Without intending to be limited by theory, the characteristics of the Airy beam 312 are affected by the phase modulation of the Gaussian beam 112, the phase adjustment device 120, and the focusing lens 130. Specifically, Figure 1D The exemplary Airy beam focusing region 313 depicted is composed of a 1 / e beam with a diameter of 6 mm. 2A Gaussian beam with a diameter and wavelength λ = 1064 nm uses a beam with the characteristics of equation (1) (which has α = 1.2 x 10⁻⁶). -4 The phase adjustment device 120 generates the phase function defined therein, and focuses it using a focusing lens 130 with a focal length of 30mm. Figure 1D In the example, the main lobe 315 has a cross-section of 10 μm × 10 μm and contains 47.7% of the total laser energy of the Airy beam focusing region 313.

[0093] Now for reference Figure 2A and Figure 2B When the Airy beam 312 is guided into the transparent workpiece 160, the Airy beam focusing region 313 induces absorption of laser energy within the transparent workpiece 160, thereby forming a bending defect 172. In operation, the bending defect 172 of the profile 170 is generated through the interaction between the transparent workpiece 160 and the Airy beam focusing region 313. Specifically, the main lobe 315 of the Airy beam focusing region 313 can generate multiphoton absorption (MPA) in the transparent workpiece 160. MPA is the simultaneous absorption of two or more photons of the same or different frequencies, which excites a molecule from a state (typically the ground state) to a higher-energy electronic state (i.e., ionization). The energy difference between the lower and higher states involved in the molecule is equal to the sum of the energies of the involved photons. MPA (also known as induced absorption) can be, for example, a second- or third-order (or higher-order) process, several orders of magnitude weaker than linear absorption. It differs from linear absorption in that, for example, the intensity of second-order induced absorption can be proportional to the square of the light intensity, thus it is a nonlinear optical process. Without being bound by theory, sufficient energy is deposited in the transparent workpiece 160 to induce absorption to break the chemical bonds of the transparent workpiece 160 at intervals along the contour line 165, thereby forming a bending defect 172.

[0094] Still referencing Figure 2A and Figure 2B A profile 170 comprising a series of bending defects 172 can be formed in the transparent workpiece 160 by irradiating the profile line 165 with an Airy beam 312 and translating at least one of the Airy beam 312 and the transparent workpiece 160 relative to each other along the profile line 165 to form bending defects 172 in the profile 170. The Airy beam 312 can project an Airy beam spot 317 onto the first surface 162 of the transparent workpiece 160, the Airy beam spot 317 corresponding to... Figure 1D The cross-sectional shape of the Airy beam 312 is depicted in the image. According to one or more embodiments, this can be achieved by moving the transparent workpiece 160 (e.g., a translation stage 190 coupled to the transparent workpiece 160). Figure 3AThe Airy beam 312 is translated across the transparent workpiece 160 by the movement of the Airy beam 312 or the movement of both the transparent workpiece 160 and the Airy beam 312. By translating at least one of the Airy beams 312 relative to the transparent workpiece 160, a plurality of bending defects 172 can be formed in the transparent workpiece 160.

[0095] Although Figure 2A The outline 170 depicted is linear, but it should be understood that the outline 170 can be non-linear, for example, curved. Furthermore, in some embodiments, the outline 170 can be a closed outline, such as a circle, rectangle, ellipse, square, hexagon, oval, regular geometric shape, irregular shape, polygon, arbitrary shape, etc. Furthermore, the bending defects 172 can typically be spaced apart from each other along the profile 170 by distances ranging from 0.1 μm to 500 μm, such as 1 μm to 200 μm, 2 μm to 100 μm, or 5 μm to 20 μm, 0.1 μm to 50 μm, 5 μm to 15 μm, 5 μm to 12 μm, 7 μm to 15 μm, 8 μm to 15 μm, or 8 μm to 12 μm, such as 50 μm or less, 45 μm or less, 40 μm or less, 35 μm or less, 30 μm or less, 25 μm or less, 20 μm or less, 15 μm or less, 10 μm or less, such as 100 μm, 75 μm, 50 μm, 40 μm, 30 μm, 25 μm, 10 μm, 5 μm, or any range with any two of these values ​​as endpoints.

[0096] Still referencing Figure 2A and Figure 2B After the contour 170 of the bending defect 172 is formed, the transparent workpiece 160 can be further acted upon in a subsequent separation step to cause the transparent workpiece 160 to separate along the contour 170. For example... Figure 2B As shown, separation of the transparent workpiece 160 forms one or more non-square edges 168 within the transparent workpiece 160. Subsequent separation steps may include using mechanical force, forces induced by thermal stress, or chemical etchants to propagate cracks along contour 170. A heat source, such as an infrared laser beam, may be used to generate thermal stress, thereby separating the transparent workpiece 160 along contour 170. Separating the transparent workpiece 160 may include directing an infrared laser beam at contour 170 to induce thermal stress to propagate cracks along contour 170. In some embodiments, an infrared laser beam may be used to initiate separation, and the separation may subsequently be performed mechanically. Example infrared lasers include carbon dioxide lasers (“CO2 lasers”), carbon monoxide lasers (“CO lasers”), solid-state lasers, laser diodes, or combinations thereof.

[0097] Without being constrained by theory, an infrared laser is used as a controlled heat source to rapidly raise the temperature of the transparent workpiece 160 at or near profile 170. This rapid heating can create compressive stress in or near profile 170 within the transparent workpiece 160. Since the area of ​​the heated glass surface is relatively small compared to the total surface area of ​​the transparent workpiece 160, the heated area cools relatively quickly. The resulting temperature gradient induces tensile stress in the transparent workpiece 160 sufficient to propagate a crack along profile 170 and through the depth of the transparent workpiece 160, thereby causing the transparent workpiece 160 to completely separate along profile 170. Without being constrained by theory, it is believed that the tensile stress can be caused by the expansion (i.e., the change in density) of the glass in the portion of the transparent workpiece 160 with the higher local temperature.

[0098] like Figure 2A and Figure 2B As shown, a non-square edge 168 (e.g., a bull's nose edge) is formed by separating a transparent workpiece 160 along the contour 170 of a bending defect 172. The shape of the plurality of bending defects 172 controls the shape of the resulting non-square edge 168. The shape of the plurality of bending defects 172 is determined by the trajectory of the Airy beam focusing region 313 in the beam propagation direction at a depth through the transparent workpiece 160. Without intending to be theoretically limited, two parameters affecting the trajectory of the Airy beam focusing region 313 are the phase modulation frequency of the phase adjustment device 120 and the focal length of the focusing lens 130. For example, increasing the phase modulation frequency of the phase adjustment device 120 and / or decreasing the focal length of the focusing lens 130 can reduce the radius of the non-square edge 168, which increases the curvature of the non-square edge 168. However, both increasing the phase modulation frequency of the phase adjustment device 120 and decreasing the focal length of the focusing lens 130 reduce the beam intensity of the main lobe 315. For illustration, Figure 1C and Figure 1D The Airy beam 312 described herein, including a wavelength of 1064 nm, uses a 1.2 × 10⁻⁶ nm beam. -5 The system comprises a phase adjustment device 120 with a phase modulation frequency and a focusing lens 130 with a focal length of 30 mm, and includes a main lobe 315 comprising 47.7% of the laser energy of the Airy beam focusing region 313. This is achieved by increasing the phase modulation frequency of the phase adjustment device 120 to 1.5 × 10⁻⁶. -5 The focal length of the focusing lens 130 is reduced to 15mm, and the main lobe 315 is reduced to 35% of the laser energy of the Airy beam focusing region 313.

[0099] Now for reference Figures 3A-3E One technique to increase the efficiency (fraction of laser power contained in the main lobe) of the Airy beam 312 is to use a phase modulation frequency ratio α. yA modified phase adjustment device 120' applies cubic phase modulation (the ratio of the phase modulation frequency in the y-direction to the phase modulation frequency in the x-direction), the phase modulation frequency being α. y A value less than 1 or greater than 1 causes the modulation frequencies in the x and y directions to be different. The unequal modulation frequencies in the x and y directions alter the size, shape, and energy of the Airy beam lobes (e.g., main lobes 315'A, 315'B and side lobes 316'A, 316'B) relative to the lobes (e.g., main lobe 315 and side lobe 316) of the unmodified Airy beam focusing region 313, to form a modified Airy beam focusing region 313'. For example, Figure 3A An optical system 100' is depicted, configured to convert a Gaussian laser beam 112 into a modified phase-adjusted laser beam 212', which, when focused using a focusing lens 130, forms a modified Airy beam 312' focused into a modified Airy beam focusing region 313'. The optical system 100' includes... Figure 1A The optical system 100, wherein the phase adjustment device 120 (which has a phase modulation frequency ratio of 1) is now a modified phase adjustment device 120' (which has a phase modulation frequency ratio different from 1).

[0100] In some embodiments, the modified phase adjustment device 120' includes diffractive optical elements, such as a phase plate (which may be an Airy phase plate) prefabricated on an optical surface with cubic phase modulation, and in other embodiments; the modified phase adjustment device 120' includes a spatial light modulator comprising a large number of pixels with an adjustable refractive index. In embodiments where the modified phase adjustment device 120' includes a phase plate, cubic phase masks 121'A, 121'B ( Figure 3B and Figure 3D This corresponds to the surface morphology of the phase plate. Furthermore, the modified phase adjustment device 120' can be transmissive or reflective. For example, the phase plate embodiment of the modified phase adjustment device 120' can be transmissive, and the spatial light modulator embodiment of the modified phase adjustment device 120' can be reflective.

[0101] The modified phase adjustment device 120' includes, on one or both of the x and y directions, components that are compatible with... Figure 1A The phase modulation frequency of the phase adjustment device 120 is different from that of the phase modulation frequency. For example, the phase modulation function of the modified phase adjustment device 120' can be mathematically described as in It is the phase, and α is the frequency of phase modulation. And it is the wave vector of the laser beam 112, x and y are the spatial coordinates of the phase modulation function, and α y It is the phase modulation frequency ratio defined above.

[0102] In each of the embodiments described herein, the modified phase adjustment device 120' includes a phase modulation frequency ratio less than or greater than 1. In other words, the phase modulation frequency of the modified phase adjustment device 120' in the x-direction is different from the phase modulation frequency of the modified phase adjustment device 120' in the y-direction. Without being intended to be theoretically limited, the phase modulation frequency difference can alter the size, shape, and energy of the lobes (i.e., main lobes 315'A, 315'B and side lobes 316'A, 316'B) of the modified Airy beam focusing region 313' formed by the modified phase-adjusted laser beam 212' relative to the lobes (e.g., main lobe 315 and side lobe 316) of the Airy beam focusing region 313 formed by the unmodified phase-adjusted laser beam 212. Specifically, the phase modulation frequency difference forms main lobes 315'A and 315'B, which have greater intensity convergence and an asymmetric shape relative to main lobe 315 (when using an equivalent Gaussian beam).

[0103] Now for reference Figure 3B An example phase modulation function of the modified phase adjustment device 120' is depicted as a cubic phase mask 121'A. Specifically, it has... Figure 3B The modified phase adjustment device 120' of the cubic phase mask 121'A includes a phase modulation frequency ratio α of 0.8. y A phase plate or spatial light modulator. In contrast, Figure 1A The phase modulation frequency ratio of the phase adjustment device 120 is 1. Figure 3C The intensity distribution of the beam cross-section of an embodiment including a modified Airy beam 312'A with a wavelength of 1064 nm is depicted. This is formed by passing through (or reflecting from) a modified phase adjustment device 120' having a cubic phase mask 121'A and focusing using a focusing lens 130 with a focal length of 30 mm. By reducing the phase modulation frequency ratio, the higher-order lobes (i.e., side lobes 316'A) of the modified Airy beam 312' formed using the cubic phase mask 121'A are suppressed, thereby reducing the intensity of the side lobes 316'A and increasing the intensity of the main lobe 315'A. Specifically, the main lobe 315'A comprises 55% of the laser energy of the focused region 313'A of the modified Airy beam formed using the cubic phase mask 121'A, while... Figure 1C The main lobe 315 of the Airy beam focusing region 313 comprises 47.7% of the laser energy of the Airy beam focusing region 313.

[0104] Now for reference Figure 3D Another example phase modulation function of the modified phase adjustment device 120' is depicted as a cubic phase mask 121'B. Specifically, it has Figure 3D The modified phase adjustment device 120' of the cubic phase mask 121'B includes a phase modulation frequency ratio α of 0.6. y The phase plate or spatial light modulator further suppresses the intensity of sidelobe 316'B (compared to sidelobe 316'A) and increases the intensity of main lobe 315'B (compared to main lobe 315'A). Furthermore, Figure 3E The intensity distribution of the beam cross-section of a modified Airy beam 312'B, comprising a wavelength of 1064 nm, is depicted. This modified Airy beam 312'B is formed by passing through (or reflecting from) an example modified phase adjustment device 120' having a cubic phase mask 121'B and focusing it using a focusing lens 130 with a focal length of 30 mm. Specifically, the main lobe 315'B of the modified Airy beam 312'B formed by the cubic phase mask 121'B comprises 62.4% of the laser energy of the modified Airy beam 312'B, while... Figure 1C The main lobe 315 of the Airy beam focusing region 313 comprises 47.7% of the laser energy of the Airy beam focusing region 313.

[0105] Refer again Figures 3A-3E Reducing the phase modulation frequency ratio increases the relative laser energy of the main lobe 315' of the modified Airy beam 312' and the modified Airy beam focusing region 313'. Using Figure 3A The optical component 100', at least 55% of the laser energy of the modified Airy beam focusing region 313' can be set in the main lobe 315', for example, at least 56%, at least 57%, at least 58%, at least 59%, at least 60%, at least 61%, at least 62%, at least 63%, at least 64%, at least 65%, at least 66%, at least 67%, at least 68%, at least 69%, at least 70%, at least 71%, at least 72%, or any range having any two of these values ​​as endpoints.

[0106] The main lobe 315' (e.g., 315'A, 315'B) of the modified Airy beam focusing region 313' (e.g., 313'A, 313'B) also includes 1 / e of the main lobe 315'. 2The intensity decrease defines the asymmetric shape of the lobe periphery 339. Since the main lobe 315' of the modified Airy beam focusing region 313' is asymmetric, it includes a lobe aspect ratio, defined as the ratio of the maximum range between positions of the lobe periphery 339 along the horizontal axis (i.e., the X-axis) to the maximum range between positions of the lobe periphery 339 along the vertical axis (i.e., the Y-axis). As used herein, the X-axis is the direction of Airy beam deflection, the Z-axis is the beam propagation direction, and the Y-axis is orthogonal to both the X and Z axes. The maximum horizontal (X-axis) range is depicted as the horizontal lobe axis 336, and the maximum vertical (Y-axis) range is depicted as the vertical lobe axis 335, where the horizontal lobe axis 336 intersects the vertical lobe axis 335 at the axis intersection 338. In some embodiments, the aspect ratio of the main lobe 315' is 1.1 or greater, such as 1.2 or greater, 1.3 or greater, 1.4 or greater, 1.5 or greater, 1.6 or greater, 1.7 or greater, 1.8 or greater, 1.9 or greater, 2.0 or greater, 2.1 or greater, 2.2 or greater, 2.3 or greater, 2.4 or greater, 2.5 or greater, 2.6 or greater, 2.7 or greater, 2.8 or greater, 2.9 or greater, 3.0 or greater, 3.1 or greater, 3.2 or greater, 3.3 or greater, 3.4 or greater, 3.5 or greater, 3.6 or greater, 3.7 or greater, 3.8 or greater, 3.9 or greater, 4.0 or greater, or any range having any two of these values ​​as endpoints.

[0107] Now for reference Figures 4A-4C Another way to increase the efficiency of the Airy beam 312 is to bombard it with an asymmetric laser beam (such as an elliptical beam). Figure 1A The phase adjustment device 120. Asymmetric laser beams include asymmetric Gaussian laser beams and elliptical Gaussian laser beams. Similar to using... Figure 3A The modified phase adjustment device 120' is subjected to an asymmetric laser beam impact (i.e., a phase adjustment device with a phase modulation frequency ratio of 1), altering the size, shape, and energy of the resulting laser beam lobe to produce a modified Airy beam 312' with a modified Airy beam focusing region 313' at focusing time. Similar to... Figure 3A The optical system 100' Figure 4A The optical system 100” is configured to convert a laser beam 112 into a modified phase-adjusted laser beam 212', which, when focused using a focusing lens 130, forms a modified Airy beam 312' focused into a modified Airy beam focusing region 313'. However, the optical system 100” includes Figure 1AInstead of using a modified phase adjustment device 120', the phase adjustment device 120 and beamforming element 150 are used. The beamforming element 150 includes one or more optical elements configured to change a laser beam 112 including a symmetrical cross-sectional shape to a modified laser beam 112' including an asymmetrical cross-sectional shape.

[0108] Now for reference Figure 4A and Figure 4B The modified laser beam 112' impact includes Figure 1B The phase mask 121 serves as a phase adjustment device 120 for an asymmetric beam spot 114', which has a major axis 116 and a minor axis 118 intersecting at an axial intersection 119, resulting in asymmetric phase modulation of the modified laser beam 112'. This forms a modified phase-adjusted laser beam 212', which, when focused using a focusing lens 130, forms a modified Airy beam 312' focused into the modified Airy beam focusing region 313'. Furthermore, Figure 4C The phase of the modified phase-adjusted laser beam 212' after the modified laser beam 112' impacts the phase-adjusting device 120 is depicted. In some embodiments, the major axis 116 of the asymmetric beam spot 114' is 1.5 to 5 times longer than the minor axis 118 of the asymmetric beam spot 114'.

[0109] The asymmetry of the beam cross-section (e.g., the cross-section or beam spot of laser beam 112 and modified laser beam 112') can be quantified by the beam spot aspect ratio, which is defined as the ratio of the major axis 116 to the minor axis 118. Symmetric beam cross-sections (such as the Gaussian cross-section of laser beam 112) have a beam spot aspect ratio of 1.0, while elliptical and other asymmetric beam cross-sections (such as the asymmetric beam spot 114' of modified laser beam 112') have a beam spot aspect ratio greater than 1.0, for example, 1.1 or greater, 1.2 or greater, 1.4 or greater, 1.5 or greater, 1.6 or greater, 1.8 or greater, 2.0 or greater, 2.2 or greater, 2.4 or greater, 2.5 or greater, 2.6 or greater, 2.8 or greater. Large, 3.0 or greater, 3.2 or greater, 3.4 or greater, 3.5 or greater, 3.6 or greater, 3.8 or greater, 4.0 or greater, 4.2 or greater, 4.4 or greater, 4.5 or greater, 4.6 or greater, 4.8 or greater, 5.0 or greater, 5.2 or greater, 5.4 or greater, 5.5 or greater, 5.6 or greater, 5.8 or greater, 6.0 or greater, 6.5 or greater, 7.0 or greater, 8.0 or greater, or any range having any two of these values ​​as endpoints. Without intending to be theoretically limited, increasing the beam aspect ratio of the asymmetric beam spot 114' (i.e., increasing the asymmetry of the asymmetric beam spot 114') increases the relative energy in the main lobe 315 of the resulting modified Airy beam focusing region 313'.

[0110] Refer again Figure 4A The beamforming element 150 is positioned upstream of the phase adjustment device 120 such that a laser beam 112 emitted by the beam source 110 (e.g., a Gaussian beam with a symmetrical cross-section) is converted from the laser beam 112 into a modified laser beam 112' with an asymmetrical cross-section (i.e., an asymmetrical Gaussian beam) before impacting the phase adjustment device 120. The phase adjustment device 120 converts the modified laser beam 112' into a modified phase-adjusted laser beam 212', which, when focused using the focusing lens 130, forms a modified Airy beam 312' focused into the modified Airy beam focusing region 313'.

[0111] The beamforming element 150 includes any known or undeveloped optical components or assemblies configured to convert a laser beam with a symmetrical cross-section (such as a circular cross-section) into a laser beam with an asymmetrical cross-section (such as an elliptical cross-section). As an example, the beamforming element 150 may include one or more refractive optical components (such as cylindrical lenses), one or more diffractive optical components (such as spatial light modulators and phase plates), and combinations thereof. As another example, the beamforming element 150 may include an optical blocking element positioned to block portions of the laser beam 112 propagating between the beam source 110 and the phase adjustment device 120. As yet another example, the beamforming element 150 may include an optical delay plate positioned to block portions of the laser beam 112 propagating between the beam source 110 and the phase adjustment device 120, such that these portions combine to project an asymmetrical beam spot 114' onto the phase adjustment device 120. As yet another example, beamforming element 150 may include a waveplate (such as a split quarter-wave plate) positioned to induce orthogonal polarization in different portions of the laser beam propagating between beam source 110 and phase adjustment device 120, such that these portions are incoherently combined at phase adjustment device 120 to project an asymmetric beam spot 114' onto phase adjustment device 120.

[0112] Now for reference Figures 5A-5B The intensity distribution of the beam cross section of the modified Airy beam 312' is depicted. The modified Airy beam 312' is formed by impacting the modified laser beam 112' with an asymmetric beam spot 114' onto the phase adjustment device 120. The asymmetric beam spot 114' has a different beam spot aspect ratio (i.e., different asymmetries). Figure 5A The intensity distribution of the beam cross-section of an embodiment of a modified Airy beam 312' is depicted. The modified Airy beam 312' is formed by impacting (through, reflecting) a modified laser beam 112' having an asymmetric beam spot 114' with a major axis of 6 mm and a minor axis of 1.5 mm 118 (i.e., a beam spot aspect ratio of 4.0). The modified Airy beam focusing region 313' includes a main lobe 315'C and side lobes 316'C, wherein the main lobe 315'C comprises 68% of the laser energy of the modified Airy beam focusing region 313', while... Figure 1C The main lobe 315 of the Airy beam focusing region 313 comprises 47.7% of the laser energy of the Airy beam focusing region 313.

[0113] Figure 5BThe intensity distribution of the beam cross-section of an embodiment of a modified Airy beam 312' and a modified Airy beam focusing region 313' is depicted. The modified Airy beam 312' and modified Airy beam focusing region 313' are formed by impinging a modified laser beam 112' with an asymmetric beam spot 114', including a wavelength of 1064 nm, onto a phase adjustment device 120 and subsequently through a focusing lens 130 with a focal length of 30 mm. The asymmetric beam spot 114' has a major axis of 6 mm and a minor axis of 2 mm 118 (i.e., a beam spot aspect ratio of 3.0). The modified Airy beam focusing region 313' includes a main lobe 315'D and side lobes 316'D, wherein the main lobe 315'D comprises 67% of the laser energy of the modified Airy beam focusing region 313', while... Figure 1C The main lobe 315 of the Airy beam focusing region 313 comprises 47.7% of the laser energy of the Airy beam focusing region 313.

[0114] Refer again Figures 4A-5B By increasing the beam aspect ratio of the modified laser beam 112', the relative laser energy of the main lobe 315 of the modified Airy beam 312' and the modified Airy beam focusing region 313' is increased. Figure 4A At least 50%, at least 52%, or at least 55% of the laser energy of the modified Airy beam focusing region 313' of the optical component 100" may be set in the main lobe 315', for example, at least 56%, at least 57%, at least 58%, at least 59%, at least 60%, at least 61%, at least 62%, at least 63%, at least 64%, at least 65%, at least 66%, at least 67%, at least 68%, at least 69%, at least 70%, at least 71%, at least 72%, or any range having any two of these values ​​as endpoints.

[0115] Still referencing Figure 5A and Figure 5B The modified Airy beam focusing regions 313'' main lobes 315'C and 315'D also include an asymmetric shape with a lobe periphery 339, similar to... Figure 3C and Figure 3EThe main lobes are 315'A and 315'B. For example, the main lobes 315'C and 315'D may have a beam aspect ratio of 1.1 or greater, such as 1.2 or greater, 1.3 or greater, 1.4 or greater, 1.5 or greater, 1.6 or greater, 1.7 or greater, 1.8 or greater, 1.9 or greater, 2.0 or greater, 2.1 or greater, 2.2 or greater, 2.3 or greater, 2.4 or greater, 2.5 or greater, 2.6 or greater, 2.7 or greater, 2.8 or greater, 2.9 or greater, 3.0 or greater, 3.1 or greater, 3.2 or greater, 3.3 or greater, 3.4 or greater, 3.5 or greater, 3.6 or greater, 3.7 or greater, 3.8 or greater, 3.9 or greater, 4.0 or greater, or any range having any two of these values ​​as endpoints.

[0116] because Figure 3C , Figure 3E , Figure 5A and Figure 5B The main lobes 315'A-315'D include an asymmetrical shape when the modified Airy beam focusing regions 313'A-313'D are used to form the contour 170 of the bending defect 172. Figure 2A and Figure 2B When the modified Airy beam focusing region 313'A-313'D is used, it can be oriented such that the horizontal lobe axis 336 of the main lobe 315'A-315'D is aligned with the desired separation line (i.e., the contour line 165) to help control the crack direction during the separation of the transparent workpiece 160, thereby improving the edge strength of the resulting non-square edge 168. Figure 2B For example, a bending defect 172 formed using a modified Airy beam focusing region 313' including main lobes 315'A-315'D can include a central defect region 175 formed at the intersection 338 of the horizontal lobe axis 336 and the vertical lobe axis 335 of the main lobes 315'A-315'D. Figure 7A ) and one or more radial arms 174 formed in the direction of the horizontal lobe axis 336 of the main lobe 315'A-315'D. Figure 7A For example, one or more radial arms 174 ( Figure 7A It can be oriented along the contour line 165 to help control the crack direction during separation of the transparent workpiece 160. Although Figure 7A An illustrative example of a bending defect formed using any of the modified Airy beam focusing regions described above (where the major axis of the main lobe is aligned with the desired separation line) is provided, but Figure 7A The specific bending defect 172 depicted is achieved using a method with... Figure 5A The modified laser beam focusing region 313'C is formed by the main lobe 315'C.

[0117] Now for reference Figures 1A-5B An embodiment is conceived, wherein Figure 4A The beamforming element 150 is positioned at Figure 3A Upstream of the phase adjustment device 120', a laser beam 112 emitted by the beam source 110 (e.g., a Gaussian beam with a symmetrical cross-section) is converted from the laser beam 112 to a modified laser beam 112' with a cross-sectional asymmetry (i.e., an asymmetric Gaussian beam) before impacting the modified phase adjustment device 120'. The modified phase adjustment device 120' converts the modified laser beam 112' into a modified phase-adjusted laser beam 212', which, when focused using the focusing lens 130, forms a modified Airy beam 312' focused into the modified Airy beam focusing region 313'. Without intending to be theoretically limited, the modified laser beam 112', with its cross-sectional asymmetry and a modified phase adjustment device 120' having a phase modulation frequency ratio different from 1, is used in conjunction with an embodiment that combines the modified laser beam 112' with the phase adjustment device 120. Figure 4A ) and embodiments using laser beam 112 and modified phase adjustment device 120' ( Figure 3A When compared, the resulting modified Airy beam focusing region 313' main lobe 315' can have an increased aspect ratio. In other words, combining these techniques can further increase the aspect ratio of the modified Airy beam focusing region 313' main lobe 315.

[0118] Now for reference Figures 1A-5BIn any embodiment, the laser beam 112 may include a pulsed laser beam such that the resulting Airy beam is a pulsed Airy beam comprising pulse trains having two or more sub-pulses per pulse train. The pulse trains increase the amount of laser energy deposited in the transparent workpiece 160 by the main lobe 315 of the Airy beam focusing region (i.e., the pulsed Airy beam focusing region) without increasing the maximum intensity. In some embodiments, the pulsed Airy beam comprises pulse trains having 2 to 30 sub-pulses, such as 2 to 25 sub-pulses, 2 to 20 sub-pulses, 2 to 25 sub-pulses, 2 to 12 sub-pulses, 2 to 10 sub-pulses, 2 to 8 sub-pulses, 2 to 5 sub-pulses, or any range having any two of these values ​​as endpoints. A pulse train is a short, fast group of subpulses (i.e., a tight cluster of subpulses), such as subpulses emitted by beam source 110 and interacting with the material (i.e., the MPA in the material of transparent workpiece 160). Using pulse trains (as opposed to single-pulse operation) increases the size (e.g., cross-sectional size) of the bending defects 172, which facilitates the connection of adjacent bending defects 172 when separating transparent workpiece 160 along contour 170, thereby minimizing crack formation in the bulk of the remaining portion of transparent workpiece 160.

[0119] Compared to the fracture resistance of a similarly shaped profile 170 with the same spacing between adjacent bending defects 172 in the same transparent workpiece 160 (which is formed using a single-pulse laser with the same energy as the combined energy of the sub-pulses of the pulse train), the force required to separate the transparent workpiece 160 along the profile 170 (i.e., the fracture resistance) is reduced when the bending defects 172 of the profile 170 are formed by a pulse train with at least two sub-pulses. Without intending to be theoretically limited, if Airy beam focusing regions 313, 313' are directed into the transparent workpiece 160 as a pulse train (i.e., a pulsed Airy beam focusing region), and the time between temporally adjacent sub-pulses is equal to or less than the thermal diffusion rate in the transparent workpiece 160, the temperature rise in the transparent workpiece 160 from subsequent sub-pulses is cumulative. This cumulative temperature rise can extend through the depth of the transparent workpiece 160, increasing the induced absorption imparted by the Airy beam focusing regions 313, 313' and reducing undesirable nonlinear effects.

[0120] Without being bound by theory, the energy required to modify the transparent workpiece 160 is pulse energy, which can be described by pulse train energy (i.e., the combined energy of all sub-pulses within a pulse train). Pulse energy (e.g., pulse train energy) can be 25 μJ to 1000 μJ or 25 μJ to 750 μJ, such as 100 μJ to 600 μJ, 50 μJ to 500 μJ, or 50 μJ to 250 μJ, for example, 25 μJ, 50 μJ, 75 μJ, 100 μJ, 200 μJ, 250 μJ, 300 μJ, 400 μJ, 500 μJ, 600 μJ, 750 μJ, or any range with any two of these values ​​as endpoints, or any open range with any of these values ​​as a lower limit. Furthermore, each pulse train can include a train duration of 10 ps to 50 ns (e.g., 100 ps to 10 ns) (i.e., the time between the start of the first sub-pulse in the pulse train and the end of the last sub-pulse in the pulse train). Additionally, each pulse train can have a sub-pulse interval of 1 ps to 500 ps (e.g., 5 ps to 50 ps) between temporally adjacent sub-pulses. Furthermore, each pulse train can include a repetition rate of 100 kHz to 750 kHz, such as 200 kHz, 300 kHz, 400 kHz, 500 kHz, 600 kHz, 700 kHz, or any range having any two of these values ​​as endpoints. Without intending to be theoretically limited, by increasing the train duration while still keeping the time between temporally adjacent sub-pulses sufficiently low to induce absorption and rapid temperature rise in the transparent workpiece 160, more power can be delivered to the transparent workpiece 160 while minimizing or even avoiding undesirable nonlinear effects.

[0121] Based on the above description, it should be understood that laser processing of transparent workpieces can include forming bending defects in the transparent workpiece using a modified Airy beam to minimize accidental damage to the transparent workpiece and facilitate efficient separation with minimal roughness on the resulting non-square edges. The modified Airy beam described herein comprises an increased amount of laser energy focused in the main lobe, as opposed to an unmodified Airy beam formed by impinging a Gaussian laser beam onto a phase-adjusting device with a phase modulation frequency ratio of 1. As described herein, the increased energy in the main lobe can be achieved using a modified phase-adjusting device or an asymmetric beam. Since the main lobe is a portion of the Airy beam used to modify the transparent workpiece (e.g., a portion of the Airy beam focusing region), increasing the percentage of laser power focused in the main lobe increases the efficiency of laser processing and improves processing throughput. Furthermore, this modification increases the asymmetry of the cross-section of the bending defect to help control crack orientation during the separation of the transparent workpiece, thereby improving the edge strength of the resulting non-square edges.

[0122] Example

[0123] Example 1

[0124] Figure 6A and Figure 6B Example 1 is depicted, using an unmodified Airy beam and an Airy beam focusing region to form an example profile 170A of a bending defect 172A. Figure 6A This is a top view of the example profile 170A of the bending defect 172A formed in the example transparent workpiece 160. Figure 6B This is a side view of a single bending defect 172A. To achieve... Figure 6B The side view, example transparent workpiece 160 is cut perpendicular to contour 170A to provide a view of a single bending defect 172A. The Airy beam and Airy beam focusing area used to form contour 170A of bending defect 172A are... Figure 1A The optical component 100 is formed using a pulse-train Gaussian laser beam with a wavelength of 1064 nm, 2-20 sub-pulses per pulse train, a sub-pulse width of 10 ps, ​​a time interval between consecutive sub-pulses in the train of 10 ns–100 ns, a repetition frequency of 1 kHz, and a pulse train energy of 200 μJ. The unmodified Airy beam used to form Example 1 is achieved by making the beam have a waist of 7.03 mm (the beam intensity is 1 / e of the maximum beam intensity). 2 A Gaussian beam (twice the beam radius at the time of the beam) passes through a phase adjustment device 120 including an Airy phase mask with a phase modulation frequency ratio of 1, and is then focused using a focusing lens 130 with a focal length of 10 mm so that the focal point of the Airy beam focusing region is formed at the center depth of the transparent workpiece 160. The profile 170A of the bending defect 172A is formed in the transparent workpiece 160, which includes a 200 μm thick layer of non-ion-exchanged Corning resin. A glass block. A transparent workpiece 160 is placed on a vacuum stage, and an Airy beam linearly scans across the first surface 162 of the transparent workpiece 160 at a scanning speed of 15 mm / s. The spacing between adjacent bending defects 172A in the profile 170A is 15 μm.

[0125] Example 2

[0126] Example 2 is Figure 7A and Figure 7B The example profile 170B of the bending defect 172B depicted is formed using an elliptical Airy beam and an elliptical Airy beam focusing region, which are generated using an elliptical Gaussian laser beam. Figure 7A This is a top view of the example profile 170B of the bending defect 172B formed in the example transparent workpiece 160. Figure 7B This is a side view of a single bending defect 172B. To achieve... Figure 7B The side view, example transparent workpiece 160 is cut perpendicular to contour 170B to provide a view of a single bending defect 172B. The Airy beam and Airy beam focusing area used to form contour 170A of the bending defect 172A are... Figure 4A The optical component 100” is formed using a pulsed Gaussian laser beam with a wavelength of 1064 nm, 2-20 sub-pulses per pulse train, a sub-pulse width of 10 ps, ​​a time interval between consecutive sub-pulses in the train of 10 ns–100 ns, a repetition frequency of 1 kHz, and a pulse train energy of 200 μJ. The elliptical Airy beam of Example 2 is formed by passing a symmetrical Gaussian beam through a beamforming element 150 comprising two cylindrical lenses with focal lengths of 100 mm and 300 mm, respectively, to form a collimated elliptical Gaussian beam with a beam spot aspect ratio of 3:1 before passing the elliptical beam through a phase adjustment device 120 comprising an Airy phase mask (with a phase modulation frequency ratio of 1), and then through a focusing lens 130 comprising a focal length of 10 mm, such that the focal point of the elliptical Airy beam focusing region is at the center depth of the transparent workpiece 160. The profile 170B of the bending defect 172B is formed in a transparent workpiece 160, which includes a 200 μm thick layer of non-ion-exchanged Corning compound. A glass block. A transparent workpiece 160 is placed on a vacuum stage, and an Airy beam linearly scans across the first surface 162 of the transparent workpiece 160 at a scanning speed of 15 mm / s. The spacing between adjacent bending defects 172B in the profile 170B is 15 μm.

[0127] like Figure 7A As shown, the elliptical Airy beam used in Example 2 forms a bending defect 172B, which includes a central defect region 175 and one or more radial arms 174 (which are formed along the major axis of the main lobe of the elliptical Airy beam, such as...). Figures 3A-5B The modified Airy beam focusing area 313'). Figure 7A As shown, one or more radial arms 174 can be oriented along a desired separation line (e.g., a contour line). Compared to the bending defect 172A of Example 1, the bending defect 172B of Example 2 is more strongly linked together to help control crack direction during separation of the transparent workpiece 160. Furthermore, as... Figure 7B As shown, compared to bending defect 172A, bending defect 172B has an increased curvature. This is achieved by increasing the numerical aperture of the focusing lens 130.

[0128] Example 3

[0129] Example 3 is as follows Figure 8A and Figure 8BThe example shown is a non-square edge 168A (so-called bull's nose edge). Figure 8A This is a side view of example non-square edge 168A, which includes non-ion-exchanged Corning inlay with a thickness of 200 μm. A bull's nose shape formed in an example transparent glass workpiece 160. Figure 8B This is a front view of example 168A with non-square edges. (Using...) Figure 4A The optical component 100” forms an example non-square edge 168A in the example transparent workpiece 160 to form an elliptical Airy beam. The elliptical Airy beam is a pulsed beam consisting of a 300 μJ pulse train with 9 sub-pulses, wherein the sub-pulse interval between each sub-pulse is 12.5 ns, and the train duration is 720 ns. The pulse train used in Example 3 is repeated at a repetition rate of 200 kHz. During the laser processing of Example 3, the example transparent workpiece 160 is translated relative to the elliptical Airy beam such that the spacing between adjacent pulse trains impacting the example transparent workpiece 160 is 18 μm, and therefore the spacing between adjacent bending defects used to form the non-square edge 168A is 18 μm.

[0130] Example 4

[0131] Example 4 is an example of a non-square edge 168B, which is as follows Figure 9 The reversed bull's nose shown. Figure 9 This is a side view of an example non-square edge 168B, which includes a non-ion-exchanged Corning bead with a thickness of 200 μm. The inverted bullnose shape is formed in the example transparent glass workpiece 160. Similar to the non-square edge 168A of Example 3, it uses... Figure 4A The optical component 100” forms an example non-square edge 168B in the example transparent workpiece 160 to form an elliptical Airy beam. The elliptical Airy beam is a pulsed beam consisting of a 300 μJ pulse train with 9 sub-pulses, wherein the interval between each sub-pulse is 12.5 ns, and the train duration is 720 ns. The pulse train used in Example 4 is repeated at a repetition rate of 200 kHz. Similarly to the non-square edge 168A in Example 3, during the laser processing in Example 3, the example transparent workpiece 160 is translated relative to the elliptical Airy beam, such that the spacing between adjacent pulse trains impacting the example transparent workpiece 160 is 18 μm, and therefore the spacing between adjacent bending defects used to form the non-square edge 168B is 18 μm. Furthermore, in order to form the inverted bullnose shape of the non-square edge 168B, the numerical aperture of the focusing lens 130, the cubic coefficient of the phase adjustment device 120, and the laser parameters can be changed. In fact, these parameters can be changed to form non-square edges with various curvatures.

[0132] As used herein, the term “about” means that a quantity, dimension, formulation, parameter, and other quantity and characteristic is not, and does not need to be, precise, but may be approximate and / or larger or smaller as required, reflecting tolerances, conversion factors, rounding, measurement errors, and other factors known to those skilled in the art. When the term “about” is used at the endpoints of a value or range, the specific value or endpoint referred to is included. Regardless of whether the endpoints of a numerical value or range in the specification are marked with “about,” two embodiments are described: one modified by “about” and one not modified by “about.” It will be further understood that each endpoint of a range is significant relative to the other endpoint and independent of the other endpoint.

[0133] The directional terms used herein (e.g., up, down, right, left, front, back, top, bottom) are used only with reference to the accompanying drawings and are not intended to imply absolute orientation.

[0134] Unless otherwise expressly stated, any method described herein shall never be construed as requiring its steps to be performed in a particular order, nor requiring any particular orientation of any apparatus. Therefore, in any instance where the order in which steps are to be followed is not actually described in the method, or the order or orientation of the various components is not actually described in any apparatus, or where the description does not otherwise specifically indicate that these steps will be limited to a particular order, or where no particular order or orientation / orientation of the components of the apparatus is described, no inference shall be made in any respect of order or orientation / orientation. This applies to any possible non-explicit basis for interpretation, including: logical matters relating to the arrangement of steps, the flow of operations, the order of components, or the orientation of components; general meanings derived from grammatical organization or punctuation; and the number or type of embodiments described in the specification.

[0135] As used herein, the singular forms “a / an” and “the” include plural referents unless the context explicitly specifies otherwise. Thus, for example, a reference to “a component” includes aspects having two or more such components unless the context explicitly indicates otherwise.

[0136] It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments described herein without departing from the spirit and scope of the claimed subject matter. Therefore, it is intended that the specification cover a variety of modifications and variations to the embodiments described herein, provided that such modifications and variations fall within the scope of this document and its equivalents.

Claims

1. A method comprising directing a laser beam (112) onto a phase adjustment device (120, 120') such that the laser beam (112) downstream of the phase adjustment device (120, 120') comprises a modified Airy beam (312') having a modified Airy beam focusing region (313'), the modified Airy beam focusing region (313') comprising a main lobe (315) and a plurality of side lobes (316), wherein the main lobe (315) comprises a beam aspect ratio of 1.2 or greater, and wherein the phase adjustment device (120') comprises a phase modulation function. Where α is the phase modulation frequency. Where λ is the wavelength of the laser beam (112), x and y are the spatial coordinates of the phase adjustment device (120'), and α y It is the phase modulation frequency ratio and is 0.8 or less.

2. The method as described in claim 1, characterized in that, At least 60% of the laser energy of the modified Airy beam focusing region (313') is set in the main lobe (315).

3. The method of claim 1, further comprising guiding the modified Airy beam (312') onto a transparent workpiece (160) such that the modified Airy beam (312') forms a modified Airy beam focusing region (313') in the transparent workpiece (160), the modified Airy beam focusing region (313') inducing absorption in the transparent workpiece (160), the induced absorption generating a bending defect (172) in the transparent workpiece (160).

4. A method, the method comprising: The laser beam (112) output from the beam source (110) is guided onto the beamforming element (150) such that the laser beam (112) downstream of the beamforming element (150) comprises a modified laser beam (112') having an asymmetric cross-sectional shape; and The modified laser beam (112') is guided onto the phase adjustment devices (120, 120') such that the modified laser beam (112') projects an asymmetric beam spot (114') onto the phase adjustment devices (120, 120'), and the modified laser beam (112') downstream of the phase adjustment devices (120, 120') includes a modified Airy beam (312'), wherein the asymmetric beam spot (114') has a beam aspect ratio of 1.5 or greater, and The phase adjustment device (120, 120') includes a phase modulation function. Where α is the phase modulation frequency. Where λ is the wavelength of the laser beam (112), x and y are the spatial coordinates of the phase adjustment device (120, 120'), and α y It is the phase modulation frequency ratio and is 0.8 or less.

5. The method as described in claim 4, characterized in that, The modified Airy beam (312') includes a modified Airy beam focusing region (313'), which includes a main lobe (315) and a plurality of side lobes (316), and at least 65% of the laser energy of the modified Airy beam focusing region (313') is set on the main lobe (315).

6. The method of claim 4, further comprising: The modified Airy beam (312') is guided onto the transparent workpiece (160) such that the modified Airy beam (312') forms the modified Airy beam focusing region (313') in the transparent workpiece (160), the modified Airy beam focusing region (313') induces absorption in the transparent workpiece (160), and the induced absorption generates a bending defect (172) in the transparent workpiece (160). At least one of the transparent workpiece (160) and the modified Airy beam (312') is translated relative to each other along the contour line (165) to form a contour (170) including a plurality of bending defects (172); as well as Stress is applied to the contour (170) to separate the transparent workpiece (160) along the contour (170), thereby forming a non-square edge (168) on the transparent workpiece (160).

7. The method as described in claim 6, characterized in that: The plurality of bending defects (172) include a central defect region (175) and one or more radial arms (174) extending outward from the central defect region (175) along the contour line (165); The modified Airy beam focusing region (313') includes a main lobe (315) and multiple side lobes (316), wherein the main lobe (315) is asymmetric, including a horizontal lobe axis (336), a vertical lobe axis (335), and a lobe aspect ratio of 1.2 or greater; and When the modified Airy beam focusing region (313') induces absorption in the transparent workpiece (160) to form each bending defect (172), the horizontal lobe axis (336) of the main lobe (315) of the modified Airy beam focusing region (313') is aligned with at least one radial arm (174) of the bending defect (172).

8. A modified Airy beam (312') formed using the method according to any one of claims 1-7, said modified Airy beam (312') comprising a modified Airy beam focusing region (313') having a main lobe (315) and a plurality of side lobes (316), wherein, The main lobe (315) has a beam aspect ratio of 1.2 or greater.

9. The modified Airy beam (312') as claimed in claim 8, characterized in that, The aspect ratio of the main lobe (315) is 3 or greater, and at least 65% of the laser energy of the modified Airy beam focusing region (313') is set in the main lobe (315).

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