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

Abstract

A method of processing a transparent workpiece, comprising: directing a laser beam output by a beam source onto a phase-adjusting device such that the laser beam downstream of the phase-adjusting device is an Airy beam; and directing the Airy beam onto a surface of the transparent workpiece. The Airy beam forms an Airy beam focal region in the transparent workpiece, the Airy beam of the Airy beam focal region having a maximum intensity of 100 TW / cm 2 or less, the Airy beam of the Airy beam focal region inducing an absorption in the transparent workpiece, the induced absorption generating a bend defect in the transparent workpiece.

Description

[0001] This application claims the benefit of priority to U.S. Provisional Patent Application Serial No. 63 / 077,195, filed 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 an 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 for processing a transparent workpiece includes: guiding a laser beam output from a beam source to a phase adjustment device such that the laser beam downstream of the phase adjustment device is an Airy beam; and guiding the Airy beam onto the surface of the transparent workpiece, wherein the Airy beam forms an Airy beam focusing region in the transparent workpiece, the Airy beam in the Airy beam focusing region comprising 100 TW cm 2 At or below maximum intensity, the Airy beam in the focused region induces absorption in a transparent workpiece, which in turn generates bending defects in the transparent workpiece.

[0008] The second aspect of this disclosure includes the method of the first aspect, wherein the Airy beam in the Airy beam focusing region includes a main lobe and a plurality of side lobes, and at least 50% of the energy of the Airy beam focusing region is set on the main lobe.

[0009] The third aspect of this disclosure includes the method of the second aspect, wherein multiple sidelobes of the Airy beam focusing region have intensities below a minimum intensity threshold.

[0010] The fourth aspect of this disclosure includes the method of any of the foregoing aspects, wherein the maximum intensity of the Airy beam in the Airy beam focusing region is 75. TW cm 2 Or smaller.

[0011] The fifth aspect of this disclosure includes a method of any of the foregoing aspects, wherein the maximum intensity of the Airy beam in the Airy beam focusing region is 25. TW cm 2 Or smaller.

[0012] The sixth aspect of this disclosure includes a method of any of the foregoing aspects, wherein the maximum intensity of the Airy beam in the Airy beam focusing region is 0.7. TW cm 2 Up to 100 TW cm 2 .

[0013] The seventh 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.

[0014] The eighth aspect of this disclosure includes a method of any of the foregoing aspects, further comprising: translating at least one of the transparent workpiece and the Airy beam relative to each other along a contour line to form a contour having a plurality of bending defects.

[0015] The ninth aspect of this disclosure includes the method of the seventh aspect, wherein the interval between adjacent bending defects in a plurality of bending defects is 35 μm or less.

[0016] The tenth aspect of this disclosure includes the method of the seventh or eighth 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.

[0017] The eleventh aspect of this disclosure includes a method of any of the foregoing aspects, wherein the transparent workpiece includes 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.

[0018] According to a twelfth aspect of this disclosure, a method for processing a transparent workpiece includes: guiding a laser beam output from a beam source onto a phase-adjusting device, such that the laser beam downstream of the phase-adjusting device is an Airy beam, wherein the laser beam projects a beam spot on the phase-adjusting device, the beam spot having an energy distribution, wherein 20% or less of the total energy of the beam spot has a flux of less than 80% of the maximum flux of the beam spot; and guiding the Airy beam onto the surface of the transparent workpiece, wherein the Airy beam forms an Airy beam focusing region in the transparent workpiece, the Airy beam in the Airy beam focusing region having a flux of 0.125. TW cm 2 up to 50 TW cm 2 At its maximum intensity, the Airy beam in the focused area induces absorption in the transparent workpiece, which generates bending defects in the transparent workpiece.

[0019] The thirteenth aspect of this disclosure includes the method of the twelfth aspect, wherein the maximum intensity of the Airy beam in the Airy beam focusing region is 0.7. TW cm 2 up to 35 TW cm 2 .

[0020] The fourteenth aspect of this disclosure includes the method of the twelfth or thirteenth aspect, wherein the maximum intensity of the Airy beam in the Airy beam focusing region is 0.7. TW cm 2 up to 15 TW cm 2 .

[0021] The fifteenth aspect of this disclosure includes a method of any one of the twelfth to fourteenth aspects, wherein a laser beam passes through a diffractive optical element before irradiating a phase-adjusting device, and the diffractive optical element modifies the energy distribution of the laser beam.

[0022] The sixteenth aspect of this disclosure includes the method of any one of the twelfth to fifteenth aspects, wherein the flux of 10% or less of the total energy of the beam spot is less than 80% of the maximum flux of the beam spot.

[0023] The seventeenth aspect of this disclosure includes the method of any one of the twelfth to sixteenth aspects, wherein the flux of 5% or less of the total energy of the beam spot is less than 90% of the maximum flux of the beam spot.

[0024] The eighteenth aspect of this disclosure includes the method of any one of the twelfth to seventeenth aspects, wherein the phase adjustment device is a phase plate having cubic phase modulation.

[0025] The nineteenth aspect of this disclosure includes the method of any one of aspects twelve to eighteen, further comprising: translating at least one of a transparent workpiece and an Airy beam relative to each other along a contour line to form a contour having a plurality of bending defects; and applying stress to the contour to separate the transparent workpiece along the contour, thereby forming a non-square edge on the transparent workpiece.

[0026] According to a twentieth aspect of this disclosure, a method for processing a transparent workpiece includes: guiding a pulsed laser beam output from a beam source to a phase adjustment device, such that the pulsed laser beam downstream of the phase adjustment device is a pulsed Airy beam, wherein the pulsed laser beam comprises pulse trains having two or more sub-pulses per pulse train; and guiding the pulsed Airy beam onto the surface of the transparent workpiece, wherein the pulsed Airy beam forms a pulsed Airy beam focusing region in the transparent workpiece, the pulsed Airy beam in the focusing region having a focal length of 0.125. TW cm 2 up to 50 TW cm 2 At its maximum intensity, the pulsed Airy beam in the focusing region induces absorption in the transparent workpiece, which generates bending defects in the transparent workpiece.

[0027] The twentieth aspect of this disclosure includes the method of the twentieth aspect, wherein the maximum intensity of the pulsed Airy beam in the focusing region is 0.7. TW cm 2 up to 35 TW cm 2 .

[0028] The twentieth aspect of this disclosure includes the method of the twentieth or twenty-first aspect, wherein the maximum intensity of the pulsed Airy beam in the pulsed Airy beam focusing region is 0.7. TW cm 2 up to 15 TW cm 2 .

[0029] The 23rd aspect of this disclosure includes a method of any one of the 20th to 22nd aspects, wherein each pulse train of the pulsed laser beam comprises 2 to 12 sub-pulses.

[0030] The twentieth aspect of this disclosure includes a method of any one of the twentieth to the twentieth fourteenth aspects, wherein each pulse train of the pulsed laser beam includes a train duration of 10 ps to 5 ns.

[0031] The 25th aspect of this disclosure includes a method of any one of the 20th to 23rd aspects, wherein the phase adjustment device includes a phase plate having cubic phase modulation.

[0032] The 26th aspect of this disclosure includes a method comprising any one of aspects 20 to 25, further comprising: translating at least one of a transparent workpiece and a pulsed Airy beam relative to each other along a contour line to form a contour having a plurality of bending defects; and applying stress to the contour to separate the transparent workpiece along the contour, thereby forming a non-square edge on the transparent workpiece.

[0033] Additional features and advantages of the processes and systems described herein will be set forth in the following detailed description and will be apparent in part from the description to those skilled in the art, or may be recognized by practice of the embodiments described herein, including the following detailed description, the claims, and the drawings.

[0034] 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

[0035] The embodiments illustrated in the accompanying drawings are illustrative and exemplary in nature and are not intended to limit the subject matter defined by the claims. 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:

[0036] Figure 1AAn example optical system according to one or more embodiments 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;

[0037] Figure 1B According to one or more embodiments described herein Figure 1A Phase contour map of the phase adjustment device;

[0038] Figure 1C This refers to the use of one or more embodiments described herein. Figure 1A The optical system forms the Airy beam focusing area;

[0039] Figure 1D It is based on one or more embodiments shown and described herein. Figure 1C The beam cross-section of the Airy beam local focusing region;

[0040] Figure 2A The formation of the contour of a bending defect in a transparent workpiece according to one or more embodiments described herein is schematically depicted;

[0041] 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;

[0042] Figure 3A It is a grayscale image of an example Airy beam focusing region according to one or more embodiments shown and described herein;

[0043] Figure 3B It is based on one or more embodiments shown and described herein, using Figure 3A A grayscale image of the bending defect formed in the focused area of ​​the Airy beam;

[0044] Figure 4A This is another example grayscale image of the Airy beam focusing region according to one or more embodiments shown and described herein;

[0045] Figure 4B It is based on one or more embodiments shown and described herein, using Figure 4A A grayscale image of the bending defect formed in the focused area of ​​the Airy beam;

[0046] Figure 5A This is another example grayscale image of the Airy beam focusing region according to one or more embodiments shown and described herein;

[0047] Figure 5BIt is based on one or more embodiments shown and described herein, using Figure 5A A grayscale image of the bending defect formed in the focused area of ​​the Airy beam;

[0048] Figure 6A This is another example grayscale image of the Airy beam focusing region according to one or more embodiments shown and described herein;

[0049] Figure 6B It is based on one or more embodiments shown and described herein, using Figure 6A A grayscale image of the bending defect formed in the focused area of ​​the Airy beam;

[0050] Figure 7A A portion of the total energy in the main lobe of the Airy beam focusing region, varying with the intensity of the Airy beam focusing region, is graphically depicted according to one or more embodiments shown and described herein.

[0051] Figure 7B The relative absorption of laser energy of an Airy beam by a transparent workpiece, varying with the maximum intensity of the Airy beam, according to one or more embodiments shown and described herein, is illustrated graphically.

[0052] Figure 7C The Rayleigh length of the Airy beam focusing region, which varies with the maximum intensity of the Airy beam, according to one or more embodiments shown and described herein, is depicted graphically.

[0053] Figure 8A The optical assembly of FIG1, according to one or more embodiments shown and described herein, is schematically depicted, wherein diffractive optical elements for modifying the intensity distribution of the Airy beam are added;

[0054] Figure 8B The relative intensity of a beam spot as a function of its radial position, according to one or more embodiments shown and described herein, is schematically depicted. The beam spot has a modified intensity distribution projected onto a phase-modification device for forming a modified Airy beam.

[0055] Figure 9A It is a grayscale image of a bending defect formed by an Airy beam focusing area using the optical components of FIG1, according to one or more embodiments shown and described herein.

[0056] Figure 9B It is based on one or more embodiments shown and described herein, used for Figure 8A A grayscale image of a bending defect formed in the Airy beam focusing area of ​​an optical component, the Airy beam focusing area having a similar shape to... Figure 9A The same intensity in the focused area of ​​the Airy beam;

[0057] Figure 10 The relative intensity of laser pulses within an example pulse train according to one or more embodiments described herein is graphically depicted as a function of time.

[0058] Figure 11A It is a grayscale image of a bending defect formed by an Airy beam focusing region generated using a single-pulse laser beam, according to one or more embodiments shown and described herein; and

[0059] Figure 11B It is a grayscale image of a bending defect formed by an Airy beam focusing region generated using a pulse train laser beam, according to one or more embodiments shown and described herein. Detailed Implementation

[0060] 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 likelihood 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 that must be cleaned through additional process steps involving washing or chemical treatment. Therefore, there is a desire to replace traditional edge finishing processes with particle-free and high-throughput processes for forming non-square edges.

[0061] 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 low-intensity Airy beams to form bending defects in transparent workpieces to minimize accidental damage to the transparent workpieces and facilitate efficient separation with minimal roughness on the resulting non-square edges. Reference will now be made in detail to various embodiments of this disclosure, examples of which are illustrated in the accompanying drawings. Wherever possible, the same or similar reference numerals and symbols are used throughout the drawings to refer to the same or similar parts. The drawings are not necessarily to scale, and those skilled in the art will recognize where the drawings have been simplified to illustrate key aspects of this disclosure.

[0062] While not intended to be theoretically limited, an "Airy beam" refers to a type of laser beam that incorporates curvature in free space due to the selected 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 and intensity. 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 can be used to modify the transparent workpiece (e.g., ablate, form defects, or otherwise alter it to facilitate separation).

[0063] 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.

[0064] 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.

[0065] As used herein, a “profile” corresponds to the set of intersection points of 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.

[0066] As used herein, "profile" refers to a collection 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 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).

[0067] 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 are bent in relation to the bending 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 the transparent workpiece produced by the 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, multiple laser pulses at that specific location, or multiple pulse trains of subpulses 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.

[0068] 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 Gorilla Glass, available from Corning Incorporated, Corning, New York. ® (Corning Gorilla) ® (e.g., Nos. 2318, 2319, and 2320) 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 XG glass 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.

[0069] In ion exchange processes, 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 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.

[0070] 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 Without being theoretically limited, the Airy beam focusing region 313 is substantially independent, depending on the relative positioning of the optical system 100 and the transparent workpiece 160, allowing it to be formed both inside and / or outside the transparent workpiece 160. In fact, in Figure 1A In the schematic depiction, the Airy beam focusing region 313 extends through the thickness of the workpiece 160 and just beyond the first surface 162 and the second surface 164.

[0071] 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 / e2 The intensity drop limit (i.e., the beam diameter is the radial position corresponding to the peak intensity and the intensity is 1 / e of the maximum intensity) is defined. 2 The diameter of the Gaussian beam varies in the propagation direction. The waist of the Gaussian beam corresponds to the minimum diameter of the Gaussian beam. In some embodiments, the laser beam 112 emitted by the beam source 110 is pulsed and comprises short light pulses (e.g., in the femtosecond to picosecond range) or pulse trains of closely spaced sub-pulses. In some embodiments, the beam source 110 may output a laser beam 112 comprising wavelengths such as 1064 nm, 1030 nm, 532 nm, 530 nm, 355 nm, 343 nm, or 266 nm, or 215 nm. Furthermore, the laser beam 112 converted into an 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.

[0072] 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 applies 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 for forming 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.

[0073] Now for reference Figure 1A and Figure 1B The phase function of the Airy beam can be expressed as: = ( αk ) 3 (( x + y ) 3 +( x - y ) 3 ), or can be written as = ( αk ) 3 ( x 3 + y 3 ), where α is the phase modulation frequency, k is the wave vector of the laser beam 112, and x and y are the spatial coordinates of the phase function. Specifically, Figure 1B A cubic phase mask 121 for ultimately forming an Airy beam 312 downstream of a focusing lens 130 is illustrated in a phase adjustment device 120. In some embodiments, the phase adjustment device 120 includes diffractive optical elements, such as a phase plate (which may be an Airy phase plate) pre-fabricated on an optical surface with cubic phase modulation, and in other embodiments; the phase adjustment device 120 includes a spatial light modulator composed of 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. Furthermore, 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.

[0074] exist Figure 1C and Figure 1D The image shows the Airy beam focusing region 313 of the 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 1A and 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 side lobe 316 having 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 the intersecting rays.

[0075] Now for reference Figure 2A and Figure 2BWhen the Airy beam 312 is guided into the transparent workpiece 160, the Airy beam focusing region 313 induces the 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 generated in the transparent workpiece 160 to induce absorption deposition to break the chemical bonds of the transparent workpiece 160 at intervals along the contour line 165, thereby forming bending defects 172.

[0076] Still referencing Figure 2A and Figure 2B A contour 170 comprising a series of bending defects 172 can be formed in the transparent workpiece 160 by irradiating the contour line 165 with the Airy beam 312 and translating at least one of the Airy beam 312 and the transparent workpiece 160 relative to each other along the contour line 165 to form bending defects 172 in the contour 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. According to one or more embodiments, the Airy beam 312 can be translated across the transparent workpiece 160 by movement of the transparent workpiece 160 (e.g., movement of a translation stage 190 coupled to the transparent workpiece 160), movement of the Airy beam 312, or 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.

[0077] Although Figure 2AThe 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 be spaced apart from each other by a distance of 0.1µm to 500µm along the profile 170, such as 1µm to 200µm, 2µm to 100µm, or 5µm to 20µm, 0.1µm to 50µm, 5µm to 15µm, 5µm to 12µm, 7µm to 15µm, 8µm to 15µm, or 8µm to 12µm, such as 50µm or less, 45µm or less, 40µm or less, 35µm or less, 30µm or less, 25µm or less, 20µm or less, 15µm or less, 10µm or less, such as 100µm, 75µm, 50µm, 40µm, 30µm, 25µm, 10µm, 5µm, or any range with any two of these values ​​as endpoints.

[0078] 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 creates 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.

[0079] Without intending to be limited 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 intending to be limited 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 workpiece with the higher local temperature.

[0080] Now for reference Figures 3A-6B The influence of the maximum intensity of the Airy beam 312 used to form the bending defect 172 that contributes to the formation of one or more non-square edges 168 in the transparent workpiece 160 will now be discussed. Without intending to be theoretically limited, the maximum intensity of the Airy beam 312 is the maximum intensity of the main lobe 315 of the Airy beam 312. Without intending to be theoretically limited, the maximum intensity is formed at the focal point FP of the focusing lens 130 and in the Airy beam focusing region 313. Figures 3A-6B These are example Airy beam focusing regions 313A-313D with different maximum intensities. Figures 3A-6A The grayscale image shows an example bending defect 172A-172D formed using each of the example Airy beam focusing regions 313A-313D. Figures 3B-6B Grayscale images of each example bending defect 172A-172D, available from Corning Gorilla Glass, Corning Incorporated, Corning, NY. TM (CORNING GORILLA) TM Formed in glass. The Airy beam focusing region 313A-313D used to form bending defects 172A-172D is a 1 / e beam with a diameter of 7mm. 2 A Gaussian beam of diameter is formed, which is guided through an Airy phase plate with a cubic coefficient of α=1, and then focused into a transparent workpiece 160 using a 10mm focal length objective lens.

[0081] Figure 3A The Airy beam focusing area 313A has 30 TW cm 2 Maximum strength, Figure 4A The Airy beam focusing area 313B has 100 TW cm 2 Maximum strength, Figure 5A The Airy beam focusing area of ​​the 313C has 200 TW cm 2 The maximum strength, and Figure 6A The Airy beam focusing area 313D has 600 TW cm 2 The maximum strength. For example... Figures 3A-6B As shown, with the increase of the maximum intensity in the Airy beam focusing region 313A-313D, the width of the corresponding bending defects 172A-172D increases, and the damage extending laterally from the bending defects 172A-172D into the transparent workpiece 160 also increases. Therefore, Figures 3A-6B The results, contrary to intuition, show that increasing the maximum intensity of the Airy beam focusing region 313 beyond a maximum intensity threshold reduces the quality of the bending defect 172 formed in the transparent workpiece 160, thereby reducing the quality (e.g., smoothness or strength) of the non-square edge 168 formed as the transparent workpiece 160 separates along the contour 170 of the bending defect 172. In fact, increasing the maximum intensity of the Airy beam focusing region 313 beyond the maximum intensity threshold can increase accompanying nonlinear effects and generate incidental damage in the transparent workpiece 160.

[0082] Without intending to be theoretically constrained, the effects of incidental nonlinear processes, such as the Kerr effect and plasma defocusing, can be reduced by limiting the maximum laser intensity of the Airy beam focusing region 313. These incidental nonlinear processes negatively affect the resulting bending defect 172 by interfering with the wavefront of the Airy beam focusing region 313. One result of interfering with the wavefront of the Airy beam 312 in the Airy beam focusing region 313 is the redistribution of laser energy from the main lobe 315 to the side lobes 316. The increase in energy of the side lobes 316 can lead to an increase in nonlinear absorption of the side lobes 316, which has the effect of producing damage in the transparent workpiece 160 away from the bending defect 172. If sufficient energy is transferred from the main lobe 315, the maximum intensity of the main lobe 315 may be insufficient to induce absorption and form the bending defect 172, or the distance that the main lobe 315 propagates into the transparent workpiece 160 may be limited (e.g., less than the entire thickness). It should be understood that the absorption and bending defect 172 are induced by some nonlinear effects (i.e., MPA), so the strength of the main lobe 315 required to induce absorption and form bending defect 172 should be balanced with the accompanying nonlinear absorption in the side lobes 316 and the harmful Kerr and plasma defocusing effects.

[0083] To limit nonlinear absorption in the side lobes 316, it might be desirable to block the side lobes 316 so that only the main lobe 315 is guided into the transparent workpiece 160. However, this blocking effect would cause degradation of the Airy beam focusing region 313, preventing the proper formation of the bending defect 172. When the main lobe 315 has its highest intensity, the lower-intensity side lobes 316 store energy for perpetuation and maintenance when energy is extracted from the main lobe 315 to form the bending defect 172. A key feature of the Airy beam 312 is its "self-healing" property; that is, if the main lobe 315 is blocked, attenuated, or interrupted, and the side lobes 316 remain undisturbed, the main lobe 315 can be recovered in the Airy beam focusing region 313 a certain distance after the blocking, attenuation, or interruption by transferring energy from the side lobes 316. If the sidelobe 316 is blocked or interfered with, energy transfer from the sidelobe 316 to the main lobe 315 cannot occur, the main lobe 315 cannot recover, and after a short distance in the propagation direction, the Airy beam focusing region 313 becomes unstable. As a result, the bending defect 172 is not generated, or if the bending defect 172 is generated, the bending defect 172 is incomplete or irregular.

[0084] On the contrary, such as Figures 3A-6B As shown, limiting the maximum intensity of the Airy beam focusing region 313 below a maximum intensity threshold results in the Airy beam focusing region 313 propagating over a long distance, with more energy contained in the main lobe 315, without suffering beam quality degradation due to accompanying nonlinear effects. This improves the quality of the bending defect 172 without excessively damaging the transparent workpiece 160. Furthermore, since the low-intensity Airy beam minimizes beam quality degradation due to accompanying nonlinear effects, these low-intensity Airy beams can be used to laser process transparent workpieces at increased depths, thereby facilitating the formation of bending defects over a wide range of depths through the glass thickness. The formation of high-quality bending defects 172 contributes to the formation of high-quality non-square edges 168 after separation and minimizes lateral damage entering the separated transparent workpiece 160.

[0085] Furthermore, reducing the maximum intensity of the Airy beam focusing region 313 increases the relative intensity of the main lobe 315 compared to the side lobes 316. Since the induced absorption forming the bending defect 172 is preferentially generated by the main lobe 315, and the side lobes 316 primarily generate incidental damage to the transparent workpiece 160, this reduction in maximum intensity improves the efficiency of laser processing and the quality of the bending defect 172. In the embodiments described herein, the maximum intensity of the Airy beam focusing region 313 is maintained at a level such that at least 50% of the energy of the Airy beam focusing region 313 is concentrated in the main lobe 315.

[0086] Now for reference Figure 7ALine 22 of graph 20 depicts a fraction of the total energy in the main lobe 315 of the Airy beam focusing region 313, which is the maximum intensity of the Airy beam focusing region 313. Figure 7A The curve 20 was obtained using a transparent workpiece 160 comprising soda-lime glass with a thickness of 0.2 mm. The reduction in the energy portion deposited by the main lobe 315 at increased intensity reduces the laser processing effectiveness of the Airy beam focusing region 313 by decreasing efficiency and increasing undesirable damage caused by the side lobes 316. As used herein, the maximum intensity threshold is the intensity at which half the energy of the Airy beam focusing region 313 is set in the side lobes 316. Intensities above the maximum intensity threshold will produce large collateral nonlinear effects, which will reduce the ability of the Airy beam focusing region 313 to produce high-quality bending defects 172. In some embodiments, for example when the transparent workpiece 160 comprises fused silica, aluminosilicate glass, or borosilicate glass, the maximum intensity threshold is 100. TW / cm 2 However, it should be understood that material variations can alter the maximum intensity threshold; therefore, in some embodiments, the maximum intensity threshold of the Airy beam focusing region 313 may include 200. TW / cm 2 300 TW / cm 2 Or 400 TW / cm 2 While not intended to be theoretically limited, example transparent workpieces 160, including fused silica, include those below Corning EAGLE XG. ® The nonlinear coefficient of thermal expansion (CTE) of Corning EAGLE XG ® Including those below Corning Gorilla ® CTE of glass and soda-lime glass. Therefore, the maximum Airy intensity threshold of the Airy beam focusing region 313 for laser processing of molten silica can be higher than that for laser processing of Corning EAGLE XG. ® The maximum Airy intensity threshold, which in turn can be higher than that used for Corning Gorilla Laser processing. ® Maximum Airy intensity threshold for glass and soda-lime glass. In some embodiments, the maximum intensity of the Airy beam focusing region 313 includes 400. TW / cm 2 or smaller, 300 TW / cm 2 or smaller, 200 TW / cm 2 or smaller, 100 TW / cm 2 or smaller, 90 TW / cm 2 or smaller, 80 TW / cm 2 Or smaller, 75T W / cm 2 or smaller, 70 TW / cm 2 or smaller, 60 TW / cm 2 or smaller, 50 TW / cm 2 or smaller, 40 TW / cm 2 or smaller, 30 TW / cm 2 or smaller, 25 TW / cm 2 or smaller, 20 TW / cm 2 or smaller, 15 TW / cm 2 or smaller, 10 TW / cm 2 or smaller, 5 TW / cm 2 or smaller, 1 TW / cm 2 Or smaller, or any range having any two of these values ​​as endpoints. Without intending to be theoretically constrained, changing the maximum intensity of the Airy beam focusing region 313 alters the intensity of the entire Airy beam focusing region 313. For example, if other beam parameters remain constant, doubling the maximum intensity results in doubling the intensity throughout the entire Airy beam focusing region 313.

[0087] Now for reference Figure 7B Graph 30 depicts the relative absorption of laser energy by the transparent workpiece 160 at the Airy beam focusing region 313, varying with the maximum intensity of the Airy beam focusing region 313, as shown by line 32. To measure the result depicted by line 32 in graph 30, an experiment was performed to find the intensity at which nonlinear absorption begins in the transparent workpiece 160 (i.e., the minimum intensity threshold) by measuring the power of the Airy beam 312 after passing through the transparent workpiece 160. Figure 7B As shown, at 0.7 TW cm 2 At intensities of 160 and above, the minimum level of nonlinear absorption in the transparent workpiece 160 is exceeded. This is the minimum intensity threshold of the Airy beam focusing region 313 when guided into soda-lime glass, because... Figure 7B In the measurements described herein, 0.2 mm thick soda-lime glass was used as the transparent workpiece 160. It should be understood that material variations can alter the minimum intensity threshold; therefore, in some embodiments, the minimum intensity threshold of the Airy beam focusing region 313 may include 0.5 mm. TW / cm 2 0.25 TW / cm 2Or 0.125 TW / cm 2 It should also be understood that wavelength variation can alter the minimum intensity threshold, and the minimum intensity threshold described herein is with respect to a wavelength of 1064 nm. Without intending to be theoretically limited, a transparent workpiece 160, including a higher CTE, can be modified by an Airy beam focusing region 313 with a lower minimum intensity threshold.

[0088] In some embodiments, the minimum intensity threshold of the Airy beam focusing region 313 includes 0.125. TW / cm 2 Or larger, 0.15 TW / cm 2 Or larger, 0.2 TW / cm 2 Or larger, 0.3 TW / cm 2 Or larger, 0.4 TW / cm 2 Or larger, 0.5 TW / cm 2 Or larger, 0.6 TW / cm 2 Or larger, 0.7 TW / cm 2 Or larger, 0.75 TW / cm 2 Or larger, 0.8 TW / cm 2 Or larger, 0.9 TW / cm 2 Or larger, 1.0 TW / cm 2 This could be greater, or any range having any two of these values ​​as endpoints. Furthermore, the maximum and minimum intensity thresholds of the Airy beam focusing region 313 described above can be endpoints of several intensity ranges (e.g., the range of maximum intensity) of the Airy beam focusing region 313 for laser processing of the transparent workpiece 160. For example, the maximum intensity threshold of the Airy beam focusing region 313 could include 0.125 TW / cm². 2 up to 200 TW / cm 2 0.125 TW / cm 2 Up to 100 TW / cm 2 0.5 TW / cm 2 Up to 100 TW / cm 2 0.7 TW / cm 2 Up to 100 TW / cm 2 0.125 TW / cm 2 up to 50 TW / cm 2 0.7 TW / cm 2 up to 50 TW / cm 2 0.7 TW / cm 2 up to 35 TW / cm 2 0.7 TW / cm 2 By 25 TW / cm 2 0.7 TW / cm 2 up to 15 TW / cm 2 1 TW / cm 2 up to 50 TW / cm 2 5 TW / cm 2 up to 50 TW / cm 2 1 TW / cm 2 By 25 TW / cm 2 1 TW / cm 2 Up to 10 TW / cm 2 , or any range having any two of these values ​​as endpoints.

[0089] Now for reference Figure 7C Line 42 of graph 40 depicts the Rayleigh length of the Airy beam focusing region 313, which varies with the maximum intensity of the Airy beam focusing region 313. Figure 7A The curve 40 was obtained using a transparent workpiece 160 comprising soda-lime glass with a thickness of 0.2 mm. The Rayleigh length is defined here as the distance from the minimum width of the Airy beam focusing region 313 to a point where the beam width is equal to √2 times the minimum width. As used herein, the width of the Airy beam focusing region 313 is 1 / e of the main lobe 315. 2 Width. Without intending to be theoretically limited, when the Airy beam focusing region 313 includes a low Rayleigh length, the energy of the Airy beam focusing region 313 diffuses over short distances in a direction transverse to the propagation direction, thereby reducing the intensity of the main lobe 315 and its effectiveness in inducing absorption over long distances to form a bending defect 272 extending through the entire thickness of the transparent workpiece 160. In fact, line 42 shows a strong negative correlation between the Rayleigh length of the Airy beam focusing region 313 and an increase in the intensity of the Airy beam focusing region 313, and also shows another benefit of reducing the intensity of the Airy beam focusing region 313. For example, Figure 7C It shows how the intensity increases to 100 TW / cm 2 Rayleigh length decreases sharply.

[0090] Now for reference Figures 8A-9B An embodiment will now be described: modifying the energy distribution of the Airy beam 312 to increase the amount of laser energy deposited in the transparent workpiece 160 by the main lobe 315 of the Airy beam focusing region 313 without increasing the maximum intensity (e.g., not increasing the maximum intensity beyond the aforementioned maximum intensity threshold). One example of a method to increase the deposited laser energy while minimizing accompanying nonlinear effects is to shape the intensity distribution of the Airy beam focusing region 313 into a so-called top-cap function, or another function with weakly varying intensity over a distance in a direction transverse to the propagation direction. Using a modified Airy beam 312' with such an intensity distribution can result in a more uniform distribution of energy through the Airy beam focusing region 313 and avoid the formation of a high-intensity spot at the center of the Airy beam focusing region 313. This allows the Airy beam focusing region 313 to maintain sufficiently high energy to induce absorption in the transparent workpiece 160 along its length, while keeping the maximum intensity at or below the maximum intensity threshold. While a top-cap intensity distribution has been described herein, it should be understood that other intensity distributions may provide benefits in different situations. For example, an Airy beam focusing region having an intensity that increases as the Airy beam focusing region propagates through the transparent workpiece 160 can be used to counteract absorption in the transparent workpiece 160 to maintain a constant intensity through the depth of the transparent workpiece 160.

[0091] Now for reference Figure 8A and Figure 8B The image depicts an optical system 100'. 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'. The optical system 100' includes... Figure 1A The optical system 100 includes a diffractive optical element 150 for modifying the intensity distribution of a laser beam 112. In some embodiments, the diffractive optical element 150 includes a phase mask / plate or a spatial light modulator.

[0092] Specifically, the laser beam 112 output from beam source 110 includes a Gaussian energy distribution, and after passing through diffractive optical element 150 and reaching phase adjustment device 120, laser beam 112 (now modified laser beam 112') includes a modified top-cap energy distribution. Therefore, the beam spot 114' projected by the modified laser beam 112' onto phase adjustment device 120 ( Figure 8BThis includes the top-cap energy distribution. As used herein, "top-cap energy distribution" refers to the area within which the beam spot (e.g., Figure 8B The total energy of the beam spot (114') is less than 20% of the total energy, and the energy distribution is less than 80% of the maximum energy. Figure 8B In the illustrative example, 80% or more of the total energy of beam spot 114' is within an inner region (e.g., inner region 115) bounded by 80% of the maximum flux of beam spot 114'. In other words, the portion of beam spot 114' with flux less than 80% of the maximum flux accounts for less than 20% of the total energy of beam spot 114'.

[0093] Now for reference Figure 8B Associated with graph 60, it schematically depicts the use of Figure 8A The optical component 200' forms a beam spot 114'. Graph 60 includes line 62, which shows the relative fluence varying with the relative radial position within the beam spot 114'. The relative fluence at the peak of the fluence distribution is normalized to 1, and the balance of the fluence distribution is scaled proportionally. Figure 8B As shown, beam spot 114' includes an outer perimeter 118, an inner perimeter 116, and an inner region 115 bounded by the inner perimeter 116, the inner perimeter 116 being defined by a specific relative flux, such as 80% of the maximum flux of beam spot 114'. In some embodiments, beam spot 114' includes an energy distribution where less than 10% of the total energy of beam spot 114' has a flux of less than 80% of the maximum flux. In some embodiments, beam spot 114' includes an energy distribution where less than 5% of the total energy of beam spot 114' has a flux of less than 80% of the maximum flux. In some embodiments, beam spot 114' includes an energy distribution where less than 5% of the total energy of beam spot 114' has a flux of less than 90% of the maximum flux.

[0094] Refer again Figure 8A A modified laser beam 112' with a modified top-cap energy distribution is guided to a phase adjustment device 120 to apply cubic phase modulation to the modified laser beam 112' to form a modified phase-adjusted laser beam 212'. Figure 1ASimilar to the optical system 100, a cubic phase modulation is applied to form a modified phase-adjusted laser beam 212' such that when the modified phase-adjusted laser beam 212' is focused by the focusing lens 130, the modified phase-adjusted laser beam 212' forms a modified Airy beam 312', which is focused into a modified Airy beam focusing region 313' near the focal point FP of the focusing lens 130. Because the modified laser beam 112' includes a top-cap energy distribution, the resulting modified Airy beam focusing region 313' includes a consistent, more uniform energy distribution across the main lobe 315 of the modified Airy beam focusing region 313', thereby minimizing the maximum intensity of the modified Airy beam focusing region 313'. This allows the modified Airy beam focusing region 313' to maintain sufficiently high energy to produce induced absorption along its length, while keeping the modified Airy beam focusing region 313' at or below the maximum intensity threshold to minimize or prevent associated nonlinear effects.

[0095] In some embodiments, the optical system 100' may further include a 4F system comprising a lens pair (i.e., a first lens upstream of the second lens) and a spatial filter between the lens pair. The 4F system may be positioned between the diffractive optical element 150 and the phase adjustment device 120 such that the spatial filter blocks the 0th and higher orders of the modified laser beam 112', thereby allowing only the first order of the modified laser beam 112' to pass through the 4F system. In this configuration, Figure 8B The beam spot 114' is realized downstream of the second lens of the 4F system at a focal length of the second lens of the 4F system. Therefore, the phase adjustment device 120 can be set downstream of the second lens of the 4F system at a focal length of the second lens of the 4F system.

[0096] Now for reference Figure 9A and Figure 9B Using the Airy beam focusing region 313 of Figure 1 (which is a Gaussian Airy beam ( Figure 9A Example of bending defect 172E formed, and using Figure 8A An example bending defect 172F is formed by the modified Airy beam focusing region 313', which is formed using a Gaussian beam with a modified (i.e., top cap) energy distribution. Figure 9A Example bending defects 172E and Figure 9B The example bending defects 172F each form with the same laser intensity, i.e., total energy (i.e., spatially integrated energy). Figure 9BAs shown, the top cap energy distribution increases the induced absorption imparted by the modified Airy beam focusing region 313' and reduces the associated nonlinear effects by extending the depth through the transparent workpiece 160. Figure 9A (This is demonstrated by the transverse damage of bending defect 172E) to improve the quality of bending defect 172. In fact, Figure 9A and Figure 9B As shown, the modified Airy beam focusing region 313' allows for the use of a lower maximum strength than the Airy beam focusing region 313 without reducing the quality of the bending defect 172. For example, the maximum strength of the modified Airy beam focusing region 313' could include 0.125. TW / cm 2 up to 50 TW / cm 2 0.7 TW / cm 2 up to 50 TW / cm 2 0.7 TW / cm 2 up to 35 TW / cm 2 0.7 TW / cm 2 By 25 TW / cm 2 0.7 TW / cm 2 up to 15 TW / cm 2 1 TW / cm 2 up to 50 TW / cm 2 5 TW / cm 2 up to 50 TW / cm 2 1 TW / cm 2 By 25 TW / cm 2 1 TW / cm 2 Up to 10 TW / cm 2 1 TW / cm 2 up to 5 TW / cm 2 , or any range having any two of these values ​​as endpoints.

[0097] Now for reference Figures 10-11BThe embodiment will now be described: wherein the laser beam 112 comprises a pulsed laser beam, such that the Airy beam 312 comprises a pulsed Airy beam, the pulsed Airy beam comprising pulse trains having two or more sub-pulse pulses per pulse train. The pulse train increases 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. Figure 10 The relative intensities of the time-dependent laser pulses within the example pulse train 50 are depicted graphically. Each pulse train 50 includes at least two sub-pulses 51. For example, each pulse train 50 may include 2 to 30 sub-pulses, 2 to 20 sub-pulses, 2 to 15 sub-pulses, 2 to 12 sub-pulses, 2 to 10 sub-pulses, 2 to 5 sub-pulses, or any range having any two of these values ​​as endpoints.

[0098] A pulse train (such as pulse train 50) is a short, fast group (i.e., a tight cluster of sub-pulses, such as sub-pulses 51) emitted by beam source 110 and interacting with the material (i.e., the MPA in the material of transparent workpiece 160). Using pulse train 50 (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. The force required to separate transparent workpiece 160 along contour 170 (i.e., the fracture resistance) is reduced when the bending defects 172 of contour 170 are formed by pulse train 50 with at least two sub-pulses 51. This is compared to the fracture resistance of a contour 170 of the same shape 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 pulse train 50).

[0099] Without intending to be theoretically limited, if the Airy beam focusing region 313 is 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, then 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 region 313 and reducing associated nonlinear effects. Each pulse train 50 may include a train duration of 10 ps to 5 ns (e.g., 100 ps to 1 ns) (i.e., the time between the start of the first sub-pulse in the pulse train 50 and the end of the last sub-pulse in the pulse train 50). Without intending to be theoretically limited, by increasing the train duration while still keeping the time between temporally adjacent sub-pulses sufficiently low to produce induced 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.

[0100] Now for reference Figure 11A and Figure 11B The image depicts two example bending defects, 172G and 172H, formed using a single pulse (bending defect 172G) and a pulse train (bending defect 172). Each bending defect 172G and 172H is formed using a pulse with a strength of 0.85. TW / cm 2 The intensity of the Airy beam is focused in a specific region, but Figure 11A The bending defect 172G was formed using a single pulse, while the bending defect 172H was formed using a pulse train with 11 sub-pulses, each sub-pulse spaced 20 ns apart. Figure 11A In the process, the bending defect 172G is weak because only a minimal amount of nonlinear absorption occurs. Conversely, the nonlinear absorption formed by the pulse train with 11 sub-pulses... Figure 11B The bending defect 172H shown is formed better than bending defect 172G, and is therefore more feasible for facilitating the separation of the transparent workpiece 160 to form a non-square (e.g., bullnose) edge on the resulting separated article. Without intending to be limited by theory, the pulse train generates a higher peak temperature in the material of the transparent workpiece 160 than a single pulse, thus forming a better bending defect. In practice, Figure 11A and Figure 11B As shown, the pulsed Airy beam focusing region allows for the use of a lower maximum intensity than that formed with a non-pulsed Airy beam focusing region without reducing the quality of the bending defect 172. For example, the pulsed Airy beam focusing region may include 0.125 TW / cm 2up to 50 TW / cm 2 0.7 TW / cm 2 up to 50 TW / cm 2 0.7 TW / cm 2 up to 35 TW / cm 2 0.7 TW / cm 2 By 25 TW / cm 2 0.7 TW / cm 2 up to 15 TW / cm 2 1 TW / cm 2 up to 50 TW / cm 2 5 TW / cm 2 up to 50 TW / cm 2 1 TW / cm 2 By 25 TW / cm 2 1 TW / cm 2 Up to 10 TW / cm 2 1 TW / cm 2 up to 5 TW / cm 2 , or any range having any two of these values ​​as endpoints.

[0101] Based on the above description, it should be understood that laser processing of transparent workpieces can include: forming a profile in the transparent workpiece comprising multiple bending defects using a low-intensity Airy beam with self-bending properties to provide a high-throughput process for forming non-square edges with minimal particle generation and undesirable damage. The low-intensity Airy beam minimizes accidental damage to the transparent workpiece and facilitates efficient separation with minimal roughness of the resulting non-square edges.

[0102] 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, exact, 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 also be understood that each endpoint of a range is significant relative to the other endpoint and independent of the other endpoint.

[0103] The directional terms used in this document (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.

[0104] 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 the apparatus. Therefore, in any instance where a method claim does not actually describe the order of its steps, or any apparatus claim does not actually describe the order or orientation of the components, or where the claims or description do not otherwise specifically state that these steps will be limited to a particular order, or where no particular order or orientation / orientation of the apparatus components is described, no inference shall be made of any order or 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.

[0105] 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.

[0106] 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 the appended claims and their equivalents.

Claims

1. A method for processing a transparent workpiece (160), the method comprising: The laser beam (112) output from the beam source (110) is guided to the phase adjustment device (120) to form a phase-adjusted laser beam (212). The phase-adjusted laser beam (212) is guided through a focusing lens (130) to form an Airy beam (312), the focusing lens (130) having a focal point in the transparent workpiece (160); and The Airy beam (312) is guided onto the first surface (162) of the transparent workpiece (160), wherein the Airy beam (312) forms an Airy beam focusing region (313) in the thickness direction of the transparent workpiece (160) near the focal point of the focusing lens (130), and the Airy beam (312) in the Airy beam focusing region (313) comprises 100 TW cm 2 Or at a lower maximum intensity, the Airy beam (312) of the Airy beam focusing region (313) induces absorption in the transparent workpiece (160), wherein the induced absorption generates a bending defect (172) in the transparent workpiece (160).

2. The method as described in claim 1, characterized in that, The Airy beam (312) of the Airy beam focusing region (313) includes a main lobe (315) and a plurality of side lobes (316), and at least 50% of the energy of the Airy beam (312) of the Airy beam focusing region (313) is set on the main lobe (315).

3. The method as described in claim 1, characterized in that, The maximum intensity of the Airy beam (312) in the Airy beam focusing region (313) is 25. TW cm 2 Or smaller.

4. The method as described in claim 1, characterized in that, The phase adjustment device (120) includes a phase plate with cubic phase modulation.

5. A method for processing a transparent workpiece (160), the method comprising: The laser beam (112) output from the beam source (110) is guided to the phase adjustment device (120) to form a phase-adjusted laser beam (212). The phase-adjusted laser beam (212) is guided through a focusing lens (130) to form an Airy beam (312), the focusing lens (130) having a focal point in the transparent workpiece (160); and The laser beam (112) projects a beam spot (114') onto the phase adjustment device (120), the beam spot (114') comprising an energy distribution, wherein 20% or less of the total energy of the beam spot (114') has a flux of less than 80% of the maximum flux of the beam spot (114'); and The Airy beam (312) is guided onto a first surface (162) of the transparent workpiece (160), wherein the Airy beam (312) forms an Airy beam focusing region (313) in the thickness direction of the transparent workpiece (160) near the focal point of the focusing lens (130), and the Airy beam (312) in the Airy beam focusing region (313) comprises 0.125 TW cm 2 up to 50 TW cm 2 At maximum intensity, the Airy beam (312) of the Airy beam focusing region (313) induces absorption in the transparent workpiece (160), wherein the induced absorption generates a bending defect (172) in the transparent workpiece (160).

6. The method as described in claim 5, characterized in that: The laser beam (112) passes through the diffractive optical element (150) before illuminating the phase adjustment device (120); and The diffractive optical element (150) modifies the energy distribution of the laser beam (112).

7. The method as described in claim 5, characterized in that, The total energy of the beam spot (114') is 10% or less, having a flux of less than 80% of the maximum flux of the beam spot (114').

8. The method as described in claim 5, characterized in that, The phase adjustment device (120) includes a phase plate with cubic phase modulation.

9. A method for processing a transparent workpiece (160), the method comprising: A pulsed laser beam output from a beam source (110) is guided to a phase adjustment device (120) to form a phase-adjusted laser beam (212), the phase-adjusted laser beam (212) comprising pulse trains (50) having two sub-pulses (51) or more per pulse train (50); and The phase-adjusted laser beam (212) is guided through a focusing lens (130) to form a pulsed Airy beam, the focusing lens (130) having a focal point in the transparent workpiece (160); the pulsed Airy beam is guided onto a first surface (162) of the transparent workpiece (160), wherein the pulsed Airy beam forms a pulsed Airy beam focusing region along the thickness direction of the transparent workpiece (160) near the focal point of the focusing lens (130), the pulsed Airy beam in the pulsed Airy beam focusing region comprising 0.125 TW cm 2 up to 50 TW cm 2 The maximum intensity of the pulsed Airy beam in the focused region of the pulsed Airy beam induces absorption in the transparent workpiece (160), wherein the induced absorption generates a bending defect (172) in the transparent workpiece (160).

10. The method as described in claim 9, characterized in that: Each pulse train (50) of the pulsed laser beam comprises 2 to 12 sub-pulses (51); and each pulse train (50) of the pulsed laser beam comprises a train duration of 10 ps to 5 ns.

11. The method as described in claim 9, characterized in that, The phase adjustment device (120) includes a phase plate with cubic phase modulation.

12. The method of claim 9, further comprising: The transparent workpiece (160) and at least one of the pulsed Airy beam are 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).

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