Phase-shifted quasi-non-diffractive laser beam for high-angle laser processing of transparent workpieces

Abstract

A method for processing a transparent workpiece is provided, comprising the step of orienting a laser beam along a first beam path in a first orientation, wherein the first portion of the laser beam comprises a first laser beam focus line and generates induced absorption to create a first defect segment within the transparent workpiece. The method further comprises the step of orienting the laser beam along a second beam path in a second orientation, wherein the second portion of the laser beam comprises a second laser beam focus line and generates induced absorption to create a second defect segment within the transparent workpiece. Each of the first and second laser beam focus lines comprises a circular angular spectrum within the transparent workpiece; and at least one of the laser beam focus lines comprises an internal focus line angle greater than 10° with respect to a plane orthogonal to the impact surface at the impact location.

Description

Technology Field

[0001] This application claims priority to U.S. provisional patent application No. 63 / 037,154 filed on June 10, 2020, under 35 USC§119(e), the contents of which are incorporated into the present invention by reference.

[0002] This specification generally relates to an apparatus and method for laser processing a transparent workpiece, and more specifically, to a laser beam comprising a laser beam focal line that is quasi-non-diffracting and maintains quasi-non-diffracting characteristics when directed toward a transparent workpiece at a non-perpendicular angle of incidence. Background Technology

[0003] The laser processing area of ​​materials encompasses various applications, including cutting, drilling, milling, welding, and melting of various types of materials. Among these processes, of particular interest is the cutting or separation of different types of transparent substrates in processes that can be used for the production of materials such as glass, sapphire, or fused silica for thin-film transistors (TFTs), or display materials for electronic devices. The problem to be solved

[0004] There are many opportunities to improve the cutting and separation of glass substrates from the perspectives of process development and cost. There is significant interest in having a method for separating glass substrates that is faster, cleaner, cheaper, more repeatable, and more reliable than what is currently practiced in the market. Many methods for separating glass substrates result in fragile, square separation edges, which are often beveled or rounded to minimize the risk of breakage. Currently, non-square edges are often processed using mechanical means such as mechanical grinding and polishing. However, such processes generate glass dust and particles, which must be cleaned by additional process steps involving washing or chemical treatment. Therefore, there is a need for an alternative and improved method for glass substrate separation that replaces conventional edge finishing processes with particle-free, high-throughput processes. means of solving the problem

[0005] According to a first aspect of the present disclosure, a method for processing a transparent workpiece comprises: a step of directing a laser beam passing through the impact surface of the transparent workpiece at a collision location toward the transparent workpiece in a first orientation along a first beam path; and a step of adjusting the laser beam in a second orientation along a second beam path so that the laser beam passes through the impact surface at a second collision location and enters the transparent workpiece; wherein a first portion of the laser beam directed toward the transparent workpiece includes a first laser beam focus line and generates induced absorption to create a first defect segment within the transparent workpiece; a second portion of the laser beam directed toward the transparent workpiece includes a second laser beam focus line and generates induced absorption to create a second defect segment within the transparent workpiece; each of the first and second laser beam focus lines includes a circular angle spectrum within the transparent workpiece; and at least one of the first laser beam focus line and the second laser beam focus line includes an internal focus line angle greater than 10° with respect to a plane orthogonal to the impact surface at the collision location.

[0006] A second aspect of the present disclosure comprises a method of a first aspect, wherein each of the first and second laser beam focus lines is a wavelength l ; Spot size w o ; and F D Larger Rayleigh range Z R Includes, and here F D is a dimensionless divergence coefficient containing values ​​greater than or equal to 10.

[0007] A third aspect of the present disclosure comprises a method of the first aspect or the second aspect, wherein each of the first and second laser beam focus lines comprises a length defined by a series of points, each point is formed from a plurality of intersecting rays from a laser beam, and said intersecting rays are phase-matched.

[0008] A fourth aspect of the present disclosure comprises a method of any one of the prior aspects, wherein a laser beam comprises a first set of rays and a second set of rays, and the first set of rays defines a first annular segment of the laser beam and the second set of rays defines a second annular segment of the laser beam such that at least one of the first set of rays and the second set of rays comprises a circular angular spectrum within a transparent workpiece.

[0009] A fifth aspect of the present disclosure comprises a method of any one of the prior aspects, wherein one of a first set of rays and a second set of rays forms an aberration laser beam within a transparent workpiece.

[0010] A sixth aspect of the present disclosure comprises a method of any one of the prior aspects and further comprises the step of colliding a laser beam with a phase-changing optical element to apply a phase change to the laser beam.

[0011] A seventh aspect of the present disclosure comprises a method of any one of the prior aspects, wherein a laser beam having a phase change comprises a non-circular angular spectrum when generated in free space.

[0012] The eighth aspect of the present disclosure comprises a method of any one of the prior aspects, wherein the laser beam comprises a non-circular angle spectrum along a first beam path, a second beam path, or both upstream of the collision surface.

[0013] A ninth aspect of the present disclosure comprises a method of any one of the prior aspects, wherein the phase-changing optical element comprises a static phase-changing optical element.

[0014] The tenth aspect of the present disclosure comprises a method of any one of the prior aspects, wherein a static phase-changing optical element comprises a rectangular axicon having a base portion and a conical portion extending from the base portion; said base portion comprises a rectangular perimeter having a symmetry axis extending from a first axial end having a first radius of curvature to a second axial end having a second radius of curvature, wherein the first radius of curvature of said base portion and the second radius of curvature of said base portion are different.

[0015] The eleventh aspect of the present disclosure includes a method of any one of the prior aspects, wherein the phase-changing optical element includes an adaptive phase-changing optical element.

[0016] A twelfth aspect of the present disclosure comprises a method of any one of the prior aspects, wherein the adaptive phase-changing optical element comprises a spatial light modulator, a deformable mirror, or an adaptive phase plate.

[0017] The 13th aspect of the present disclosure comprises a method of any one of the prior aspects, wherein the angle of at least one of the first laser beam focus line and the second laser beam focus line is 10° to 40°.

[0018] The 14th aspect of the present disclosure comprises a method of any one of the prior aspects, wherein the angle of at least one of the first laser beam focus line and the second laser beam focus line is 15° to 40°.

[0019] The 15th aspect of the present disclosure comprises a method of any one of the prior aspects, wherein the angle of at least one internal focus line of the first laser beam focus line and the second laser beam focus line is 20° to 40°.

[0020] The 16th aspect of the present disclosure comprises a method of any one of the prior aspects and further comprises the step of translating at least one of a transparent workpiece and a laser beam along a contour line relative to each other to form a contour including a plurality of defects.

[0021] The 17th aspect of the present disclosure comprises a method of any one of the prior aspects, wherein the contour comprises a curved contour, and the contour comprises a curved contour, and the method further comprises the step of rotating the laser beam while translating at least one of a transparent workpiece and a laser beam along the curved contour so that each of the defects of the plurality of defects is oriented radially inward or radially outward with respect to the curved contour.

[0022] The 18th aspect of the present disclosure includes a method of any one of the prior aspects, wherein the curved contour includes a closed curved contour and the curved contour includes a closed curved contour.

[0023] The 19th aspect of the present disclosure comprises a method of any one of the prior aspects and further comprises the step of applying stress to the contour to separate a transparent workpiece along the contour.

[0024] The 20th aspect of the present disclosure includes a method of any one of the prior aspects, wherein stress includes thermal stress, mechanical stress, or a combination thereof.

[0025] The 21st aspect of the present disclosure comprises a method of any one of the prior aspects, wherein the laser beam comprises a pulsed laser beam output by a beam source that generates a pulsed burst comprising two or more sub-pulses per pulsed burst.

[0026] The 22nd aspect of the present disclosure includes a method of any one of the prior aspects, wherein a dimensionless divergence coefficient ( F D ) includes values ​​of about 10 to about 2000.

[0027] The 23rd aspect of the present disclosure comprises a method of any one of the prior aspects, wherein the spacing between adjacent defects is about 50 μm or less.

[0028] The 24th aspect of the present disclosure comprises a method of any one of the prior aspects, wherein the transparent workpiece comprises an alkali aluminosilicate glass material.

[0029] The 25th aspect of the present disclosure includes a method of any one of the prior aspects, wherein the collision surface includes a non-planar terrain.

[0030] A 26th aspect of the present disclosure comprises a method of any one of the prior aspects, wherein a laser beam comprises a first set of rays and a second set of rays, and the method further comprises the step of colliding the laser beam with a phase-changing optical element to apply a phase change to the laser beam.

[0031] A 27th aspect of the present disclosure comprises a method of any one of the prior aspects, wherein at least one of a first set of rays and a second set of rays comprises a circular angle spectrum within a transparent workpiece, said first set of rays defines a first annular segment of a laser beam and said second set of rays defines a second annular segment of a laser beam; said average radius of said first annular segment is smaller than the average radius of said second annular segment; said first set of rays forms at least a portion of a first laser beam focal line that terminates at an end point within a transparent workpiece; said second set of rays is aligned such that, when said second set of rays comprises a circular angle spectrum within a transparent workpiece, said second set of rays forms at least a portion of a second laser beam focal line that extends beyond the end point in the direction of beam propagation.

[0032] A 28th aspect of the present disclosure comprises a method of any one of the prior aspects, wherein a first set of rays defines a first annular segment of a laser beam and a second set of rays defines a second annular segment of a laser beam; the average radius of the second annular segment is smaller than the average radius of the first annular segment; the first set of rays forms at least a portion of a first laser beam focal line starting from an origin within a transparent workpiece; and the second set of rays is aligned such that, where the second set of rays includes a circular angle spectrum within the transparent workpiece, the second set of rays forms at least a portion of a second laser beam focal line extending to an origin in the direction of beam propagation.

[0033] A 29th aspect of the present disclosure comprises a method of any one of the prior aspects, wherein the laser beam further comprises a third set of rays defining a third annular segment; and the method further comprises the step of adjusting the laser beam in a third orientation along a third beam path so that the laser beam passes through a collision surface at a third collision location and enters a transparent workpiece.

[0034] A third aspect of the present disclosure comprises a method of any one of the prior aspects, wherein the average radius of a second annular segment is smaller than the average radius of a third annular segment; a second set of rays forms at least a portion of a second laser beam focal line that terminates at a second end point within a transparent workpiece; and a third set of rays is aligned such that, where the third set of rays includes a circular angle spectrum within the transparent workpiece, the third set of rays forms at least a portion of a third laser beam focal line that extends beyond the second end point in the direction of beam propagation.

[0035] A third aspect of the present disclosure comprises a method of any one of the prior aspects, wherein the phase-changing optical element comprises a non-circular axicon having a base portion and a conical portion extending from the base portion; said base portion comprises a non-circular circumference.

[0036] The 32nd aspect of the present disclosure includes a method of any one of the prior aspects, wherein the phase-changing optical element includes an adaptive phase-changing optical element.

[0037] A third aspect of the present disclosure comprises a method of any one of the prior aspects, wherein the adaptive phase-changing optical element comprises a spatial light modulator, a deformable mirror, or an adaptive phase plate.

[0038] The 34th aspect of the present disclosure includes the method of any one of the prior aspects, wherein the non-planar terrain of the collision surface is variable terrain.

[0039] According to the 35th aspect of the present disclosure, a method for processing a transparent workpiece comprises: a step of colliding a laser beam onto a phase-changing optical element to apply a phase change to the laser beam; and a step of directing the laser beam passing through the collision surface of the transparent workpiece at the collision location toward the transparent workpiece in a first orientation along a first beam path; wherein the laser beam comprises a first set of rays and a second set of rays, and the first set of rays defines a first annular segment of the laser beam and the second set of rays defines a second annular segment of the laser beam such that only one of the first set of rays and the second set of rays contains a circular angular spectrum within the transparent workpiece, and the first portion of the laser beam directed toward the transparent workpiece comprises a first laser beam focus line and generates induced absorption to create a defect segment within the transparent workpiece, and the first laser beam focus line is: wavelength l ; Spot size w o ; and F D Larger Rayleigh range Z R Includes, and here F D is a dimensionless divergence coefficient containing a value of 10 or more; the length is defined by a series of points, each point is formed from a plurality of cross rays from a laser beam, and the cross rays are phase-matched.

[0040] The 36th aspect of the present disclosure includes the method of the 35th aspect, wherein the first laser beam focus line further includes an inner focus line angle greater than 10° with respect to a plane orthogonal to the impact surface at the impact location.

[0041] A third aspect of the present disclosure comprises the method of a third aspect or a third aspect, wherein one of a first set of rays and a second set of rays forms an aberration laser beam within a transparent workpiece.

[0042] A third aspect of the present disclosure comprises a method of any one of aspects 35 through 37, wherein the laser beam comprises a non-circular angle spectrum along a first beam path upstream of the collision surface.

[0043] The 39th aspect of the present disclosure comprises a method of any one of the 35th through 38th aspects, wherein a set of rays forming a circular angular spectrum within a transparent workpiece comprises a non-circular angular spectrum when generated in free space.

[0044] The 40th aspect of the present disclosure comprises a method of any one of aspects 35 through 39, wherein the average radius of the second annular segment is smaller than the average radius of the first annular segment; the first set of rays comprises a circular angle spectrum within a transparent workpiece and forms at least a portion of a first laser beam focus line starting from an origin within the transparent workpiece; and the second set of rays is aligned such that, where the second set of rays comprises a circular angle spectrum within the transparent workpiece, the second set of rays forms at least a portion of a second laser beam focus line extending to an origin in the direction of beam propagation.

[0045] The 41st aspect of the present disclosure comprises a method of any one of aspects 35 through 40, and further comprises the step of adjusting a laser beam in a second orientation along a second beam path so that the laser beam passes through a collision surface at a second collision location and enters a transparent workpiece; the second portion of the laser beam directed toward the transparent workpiece comprises a second laser beam focus line and generates induced absorption to create a second defect segment within the transparent workpiece; the portion of the first laser beam focus line formed by the first set of rays comprises an inner focus line angle of 0° to 10° or 170° to 180° with respect to a plane orthogonal to the collision surface; and the portion of the second laser beam focus line formed by the second set of rays comprises an inner focus line angle greater than 10° and less than 80° or greater than 100° and less than 170° with respect to a plane orthogonal to the collision surface.

[0046] The 42nd aspect of the present disclosure comprises a method of any one of aspects 35 through 41, wherein the average radius of the first annular segment is smaller than the average radius of the second annular segment; the first set of rays comprises a circular angle spectrum within a transparent workpiece and forms at least a portion of a first laser beam focal line that terminates at an end point within the transparent workpiece; and the second set of rays is aligned such that, where the second set of rays comprises a circular angle spectrum within the transparent workpiece, the second set of rays forms at least a portion of a second laser beam focal line that extends beyond the end point in the direction of beam propagation.

[0047] The 43rd aspect of the present disclosure comprises the method of aspects 35 through 42, and further comprises the step of adjusting a laser beam in a second orientation along a second beam path so that the laser beam passes through a collision surface at a second collision location and enters a transparent workpiece, wherein the second portion of the laser beam directed toward the transparent workpiece comprises a second laser beam focus line and generates induced absorption to create a second defect segment within the transparent workpiece; the portion of the first laser beam focus line formed by the first set of rays comprises an inner focus line angle of 0° to 10° or 170° to 180° with respect to a plane orthogonal to the collision surface; and the portion of the second laser beam focus line formed by the second set of rays comprises an inner focus line angle greater than 10° and less than 80° or greater than 100° and less than 170° with respect to a plane orthogonal to the collision surface.

[0048] The 44th aspect of the present disclosure comprises the methods of the 35th through 43rd aspects, wherein the first set of rays comprises a portion of the second set of rays; and the second set of rays comprises a portion of the first set of rays.

[0049] The 45th aspect of the present disclosure comprises the method of the 35th through 44th aspects, wherein the laser beam further comprises a third set of rays defining a third annular segment; and the method further comprises the step of adjusting the laser beam in a third orientation along a third beam path so that the laser beam passes through a collision surface at a third collision location and enters a transparent workpiece.

[0050] The 46th aspect of the present disclosure comprises the method of the 35th through 45th aspects, wherein the average radius of the second annular segment is smaller than the average radius of the third annular segment; the second set of rays forms at least a portion of a second laser beam focal line that terminates at a second end point within a transparent workpiece; and the third set of rays is aligned such that, where the third set of rays includes a circular angle spectrum within the transparent workpiece, the third set of rays forms at least a portion of a third laser beam focal line that extends beyond the second end point in the direction of beam propagation.

[0051] The 47th aspect of the present disclosure comprises the method of the 46th aspect, wherein a portion of a first laser beam focus line formed by a first set of rays comprises an inner focus line angle greater than 10° and less than 80° or greater than 100° and less than 170° with respect to a plane orthogonal to the collision surface; a portion of a second laser beam focus line formed by a second set of rays comprises an inner focus line angle of 0° to 10° or 170° to 180° with respect to a plane orthogonal to the collision surface; and a portion of a third laser beam focus line formed by a third set of rays comprises an inner focus line angle greater than 10° and less than 80° or greater than 100° and less than 170° with respect to a plane orthogonal to the collision surface.

[0052] The 48th aspect of the present disclosure comprises the method of the 46th aspect, wherein the first set of rays comprises a portion of the second set of rays; the second set of rays comprises a portion of the first set of rays and a portion of the third set of rays; and the third set of rays comprises a portion of the second set of rays.

[0053] The 49th aspect of the present disclosure includes the methods of aspects 35 through 48, wherein the phase-changing optical element includes a static phase-changing optical element.

[0054] The 50th aspect of the present disclosure comprises the method of aspects 35 through 49, wherein a static phase-changing optical element comprises a rectangular axicon having a base portion and a conical portion extending from the base portion; said base portion comprises a rectangular periphery having a symmetry axis extending from a first axial end having a first radius of curvature to a second axial end having a second radius of curvature, and said first radius of curvature of the base portion and said second radius of curvature of the base portion are different.

[0055] The 51st aspect of the present disclosure includes the methods of the 35th through 50th aspects, wherein the phase-changing optical element includes an adaptive phase-changing optical element.

[0056] The 52nd aspect of the present disclosure comprises the method of the 35th through 51st aspects, wherein the adaptive phase-changing optical element comprises a spatial light modulator, a deformable mirror, or an adaptive phase plate.

[0057] The 53rd aspect of the present disclosure comprises the methods of the 35th through 52nd aspects, wherein the defect comprises a defect angle within a transparent workpiece greater than 10° with respect to a plane orthogonal to the collision surface at the collision location.

[0058] The 54th aspect of the present disclosure includes the method of the 35th through 53rd aspects, wherein the internal focus line angle is 10° to 40°.

[0059] The 55th aspect of the present disclosure includes the method of the 35th to 54th aspects, wherein the internal focus line angle is 15° to 40°.

[0060] The 56th aspect of the present disclosure includes the method of the 35th to 55th aspects, wherein the internal focus line angle is 20° to 40°.

[0061] The 57th aspect of the present disclosure comprises the method of the 35th to 56th aspects and further comprises the step of translating at least one of a transparent workpiece and a laser beam along a contour line relative to each other to form a contour including a plurality of defects.

[0062] The 58th aspect of the present disclosure comprises the method of aspects 35 through 57, wherein the contour comprises a curved contour and the contour comprises a curved contour, and the method further comprises the step of rotating the laser beam while translating at least one of a transparent workpiece and a laser beam relative to each other along the curved contour so that each of the defects of the plurality of defects is oriented radially inward or radially outward with respect to the curved contour.

[0063] The 59th aspect of the present disclosure includes the methods of aspects 35 through 58, wherein the curved contour includes a closed curved contour and the curved contour includes a closed curved contour.

[0064] The 60th aspect of the present disclosure comprises the method of aspects 35 through 59 and further comprises the step of applying stress to the contour to separate a transparent workpiece along the contour.

[0065] The 61st aspect of the present disclosure comprises the methods of the 35th through 60th aspects, wherein stress comprises thermal stress, mechanical stress, or a combination thereof.

[0066] The 62nd aspect of the present disclosure comprises the method of aspects 35 through 61, wherein the laser beam comprises a pulsed laser beam output by a beam source that generates a pulsed burst comprising two or more sub-pulses per pulsed burst.

[0067] The 63rd aspect of the present disclosure includes the methods of aspects 35 through 62, wherein a dimensionless divergence coefficient ( F D ) includes values ​​of about 10 to about 2000.

[0068] The 64th aspect of the present disclosure comprises the methods of the 35th through 63rd aspects, wherein the spacing between adjacent defects is about 50 μm or less.

[0069] The 65th aspect of the present disclosure comprises the methods of the 35th through 64th aspects, wherein the transparent workpiece comprises an alkali aluminosilicate glass material.

[0070] The 66th aspect of the present disclosure includes the methods of aspects 35 through 65, wherein the collision surface includes a non-planar terrain.

[0071] The 67th aspect of the present disclosure comprises the method of aspects 35 through 66, wherein the phase-changing optical element comprises a non-circular axicon having a base portion and a conical portion extending from the base portion; said base portion comprises a non-circular circumference.

[0072] The 68th aspect of the present disclosure includes the methods of aspects 35 through 67, wherein the phase-changing optical element includes an adaptive phase-changing optical element.

[0073] The 69th aspect of the present disclosure comprises the methods of aspects 35 through 68, wherein the adaptive phase-changing optical element comprises a spatial light modulator, a deformable mirror, or an adaptive phase plate.

[0074] The 70th aspect of the present disclosure includes the methods of aspects 35 through 69, wherein the non-planar terrain of the collision surface is variable terrain.

[0075] Additional features and advantages of the processes and systems described herein will be described in the following detailed description and, in part, will be readily apparent to those skilled in the art from such description or recognized by practicing the embodiments described herein, including the following detailed description and claims, as well as the attached drawings.

[0076] It should be understood that both the general description provided above and the detailed description below are intended to provide an overview or basis for explaining various embodiments and understanding the nature and characteristics of the claimed subject matter. The attached drawings are included to provide further understanding of the various embodiments and are incorporated into this specification and constitute a part thereof. The drawings serve to illustrate the various embodiments described herein and, together with the description, explain the principles and operation of the claimed subject matter. Brief explanation of the drawing

[0077] The embodiments described in the drawings are by nature illustrative and exemplary and are not intended to limit the subject matter defined by the claims. The following detailed description of exemplary embodiments can be understood when read in conjunction with the following drawings, wherein similar structures are indicated by similar reference numbers, and in the drawings: FIG. 1a schematically illustrates a perspective view of an embodiment in which the contours of defects, each having a defect angle, are laser-formed on a transparent workpiece according to one or more embodiments described herein; FIG. 1b schematically illustrates a perspective view of another embodiment in which the contours of defects, each having a defect angle, are laser-formed on a transparent workpiece according to one or more embodiments described herein; FIG. 1c schematically illustrates a side view of an embodiment in which the contours of defects, each having a defect angle, are laser-formed on a transparent workpiece according to one or more embodiments described herein; FIG. 1d schematically illustrates a perspective view of an embodiment in which the contours of defects, each having a defect angle, are laser-formed on a transparent workpiece according to one or more embodiments described herein; FIG. 2a schematically illustrates an optical assembly for laser processing a transparent workpiece comprising a beam source, an adaptive phase-changing optical element, and a lens assembly according to one or more embodiments described herein; FIG. 2b schematically illustrates an optical assembly for laser processing a transparent workpiece comprising a beam source, a static phase-changing optical element, and a lens assembly according to one or more embodiments described herein; FIG. 3a schematically illustrates the rectangular angular spectrum of a laser beam after phase changing according to one or more embodiments described herein; FIG. 3b schematically illustrates a phase mask used to phase change a laser beam according to one or more embodiments described herein; FIG. 4a schematically illustrates a front view of a rectangular axicon according to one or more embodiments described herein; FIG. 4b schematically illustrates a side view of the rectangular axicon of FIG. 4a according to one or more embodiments described herein; FIG. 5a schematically illustrates a cross-section of a laser beam according to one or more embodiments described herein; FIG. 5b schematically illustrates a cross-section of a laser beam according to one or more embodiments described herein; FIG. 5c schematically illustrates a cross-section of a laser beam according to one or more embodiments described herein; FIG. 6a schematically illustrates a phase mask used to phase change a laser beam according to one or more embodiments described herein; FIG. 6b schematically illustrates a phase mask used to phase change a laser beam according to one or more embodiments described herein; FIG. 7a schematically illustrates a side view of a transparent workpiece and a laser beam focus line according to one or more embodiments described herein; FIG. 7b schematically illustrates a side view of a transparent workpiece and a laser beam focus line according to one or more embodiments described herein; FIG. 7c schematically illustrates a side view of a transparent workpiece and a laser beam focus line according to one or more embodiments described herein; FIG. 8a graphs the relative intensity of laser pulses within an exemplary pulse burst over time according to one or more embodiments described herein; FIG. 8b graphs the relative intensity of a laser pulse versus time within another exemplary pulse burst according to one or more embodiments described herein; FIG. 8c graphs the intensity versus distance of a laser pulse according to one or more embodiments described herein; FIG. 9a schematically illustrates a side view of a transparent workpiece having the contours of angled defects according to one or more embodiments described herein; FIG. 9b schematically illustrates a side view of two separated articles formed from the transparent workpiece of FIG. 9a, each separated article comprising an angled edge according to one or more embodiments shown and described herein; FIG. 10a schematically illustrates a side view of a transparent workpiece having a closed curved contour of angular defects according to one or more embodiments described herein; FIG. 10b schematically illustrates a side view of a separated article formed from a transparent workpiece of FIG. 10a, wherein the separated article comprises a conical hole having an angled edge according to one or more embodiments shown and described herein; FIG. 11a schematically illustrates a side view of a transparent workpiece having the contours of defects extending from a collision surface to an edge surface and the contours of defects extending from an opposing surface to an edge surface, according to one or more embodiments shown and described herein; FIG. 11b schematically illustrates a side view of a separated article formed from a transparent workpiece of FIG. 11a, wherein the separated article comprises an inclined edge according to one or more embodiments shown and described herein; FIG. 12 illustrates a side view of a defect formed in a transparent workpiece according to one or more embodiments shown and described herein; FIG. 14 graphs the surface profile of a defect formed on a transparent workpiece of FIG. 12 according to one or more embodiments shown and described herein. Specific details for implementing the invention

[0078] We will now refer in detail to examples of implementations of a process for laser processing transparent workpieces, such as the glass workpiece exemplified in the attached drawings. Where possible, the same reference numbers are used throughout the drawings to indicate identical or similar parts.

[0079] According to one or more embodiments described herein, a transparent workpiece may be laser-processed to form a contour on the transparent workpiece containing a series of defects along a separation line intended to separate the transparent workpiece into two or more separate articles. In the embodiments, after separation of the transparent workpiece along the contour, each defect includes a defect angle greater than 10° so that the resulting separated articles include angled edges having an edge angle greater than 10°. The defects may be formed on the transparent workpiece using a low-diffraction beam, such as a quasi-non-diffraction beam focused at a laser beam focus line.

[0080] Using current methods, the diffraction and divergence of a conventional extended-focus laser beam (e.g., a quasi-non-diffracting beam) that does not use a phase mask as described in this disclosure increase when the beam is directed toward a transparent workpiece at an increased angle relative to normal incidence (e.g., an angle greater than 10° from normal incidence), and thus it is difficult to form a series of high-angle defects to facilitate the separation of the transparent workpiece into a separated article having an angled edge. For example, using previous laser processing techniques, aberrations are introduced into the beam when the laser beam enters a transparent workpiece having an angled, curved, or stepped surface. In the case of a Bessel beam, these aberrations cause the peak beam intensity to decrease significantly as the beam travels through the transparent workpiece, which can degrade quality or prevent the formation of high-angle defects. Although not limited by theory, in conventional angled cuts, the peak beam intensity is reduced because the central lobe of a standard Bessel beam is split into multiple lobes, and the peak intensity of the split lobes is smaller than the peak intensity of the central lobe of a non-aberrant Bessel beam. Although still not limited by theory, aberrations also reduce the Rayleigh range of the beam. Therefore, improved methods for laser processing transparent workpieces are required. Accordingly, the methods described herein utilize a phase-shifted angled laser beam focus line such that the laser beam focus line exhibits minimal divergence along the length of the laser beam focus line within the transparent workpiece, thereby facilitating the contouring of high-angle defects and the formation of separated articles having angled edges. Such methods are described herein with specific reference to the attached drawings.

[0081] As used herein, “laser processing” comprises directing a laser beam onto and / or into a transparent workpiece. In some embodiments, laser processing further comprises translating the laser beam toward the transparent workpiece, for example, along a contour or other path, or translating the transparent workpiece toward the laser beam. Examples of laser processing include using a laser beam to form a contour containing a series of defects extending into the transparent workpiece and / or using an infrared laser beam to heat the transparent workpiece. Laser processing may separate the transparent workpiece along one or more desired separation lines. However, in some embodiments, additional non-laser steps, such as applying mechanical force, may be used to separate the transparent workpiece along one or more desired separation lines.

[0082] As used herein, the "angle spectrum" of a laser beam refers to the distribution of the Fourier spectrum of the laser beam in the spatial frequency domain. In particular, such an angle spectrum represents a group of plane waves whose sum reconstructs the original beam. The angle spectrum is also referred to as the spatial-frequency distribution of the laser beam.

[0083] As used herein, "beam spot" refers to the cross-section (e.g., beam cross-section) of the laser beam at the collision location of the laser beam on the collision surface of the transparent workpiece, that is, the surface of the transparent workpiece where the laser beam is first incident. The beam spot is the cross-section at the collision location. In the embodiments described herein, the beam spot is sometimes referred to as "axially symmetric" or "non-axially symmetric." As used herein, axially symmetric refers to a shape that is symmetric or appears identical with respect to any angle of rotation about a central axis, and "non-axially symmetric" refers to a shape that is not symmetric with respect to any angle of rotation about a central axis. The axis of rotation (e.g., central axis) is most often taken as the optical axis (propagation axis) of the laser beam, which is an axis extending in the direction of beam propagation referred to herein as the z-direction.

[0084] As used herein, “upstream” and “downstream” refer to the relative positions of two locations or components along a beam path with respect to a beam source. For example, if the first component is closer to the beam source along the path traversed by the laser beam than the second component, the first component is upstream from the second component, and if the first location (place) is closer to the beam source along the path traversed by the laser beam than the second location (place), the first location (place) is upstream from the second location (place).

[0085] As used herein, "beam path" refers to the variable direction of movement of a laser beam. Such a beam path is determined by the direction of movement of the laser beam and changes according to the position and direction of the laser beam.

[0086] As used herein, the term "orientation" used in relation to "orienting a laser beam" refers to the average orientation of the laser beam, and more specifically, is the average of the angles of each individual ray within the laser beam.

[0087] As used herein, "laser beam focus line" refers to a pattern of interacting (e.g., intersecting) rays of a laser beam that forms a focus region extended in the direction of beam propagation. In conventional laser processing, the laser beam is tightly focused at a focal point. Such a focal point is the point of maximum intensity of the laser beam and is located on the focal plane of the transparent workpiece. Conversely, in the extended focus region of the focus line, the point of maximum intensity of the laser beam extends beyond the point to a line aligned with the direction of beam propagation. The focus line is formed by converging intersecting (e.g., traversing) rays to form a continuous series of focal points aligned in the direction of beam propagation. The laser beam focus lines described herein are formed using a quasi-non-diffracting beam, which is mathematically defined below.

[0088] As used herein, "contour" corresponds to a set of intersection points between the incident (impact) plane of the transparent workpiece and the laser beam, resulting from the relative movement of the laser beam and the transparent workpiece. The contour may be linear, angular, polygonal, or curved. The contour may be closed (i.e., define an area enclosed by the surface of the transparent workpiece) or open (i.e., define an area enclosed by the surface of the transparent workpiece). Such a contour indicates a boundary that allows the transparent workpiece to be easily separated into two or more parts. Separation occurs spontaneously or with the assistance of external thermal or mechanical energy.

[0089] As used herein, "contour" refers to a set of defects within a transparent workpiece formed by a laser beam through the relative movement of the laser beam and the transparent workpiece along the contour. Such defects are spaced apart along the contour, are completely contained within the interior of the transparent workpiece, and / or extend into the interior of the transparent workpiece through one or more surfaces. The defects may also extend through the entire thickness of the transparent workpiece. Separation of the transparent workpiece occurs, for example, by connecting the defects along the contour through crack propagation.

[0090] As used herein, "defect" refers to an area of ​​the transparent workpiece deformed by a laser beam focus line. Defects include areas of the transparent workpiece having a modified refractive index relative to the surrounding undeformed area of ​​the transparent workpiece. Common defects include structurally deformed areas of the transparent workpiece, such as voids, cracks, scratches, flaws, holes, perforations, densification, or other deformations, created by the laser beam focus line. Defects may also be referred to as defect lines or damage tracks in various embodiments of the present invention. Defects or damage tracks are formed through the interaction between the transparent workpiece and the laser beam focus line. As described in detail below, the laser beam focus line is generated by a pulsed laser. Defects at specific locations along the contour are formed by focus lines generated by a single laser pulse at a specific location, a pulse burst of sub-pulses at a specific location, or multiple laser pulses at a specific location. Multiple contour-forming defects are generated due to the relative movement of the laser beam and the transparent workpiece along the contour.

[0091] The phrase “transparent workpiece” as used herein means a workpiece formed of glass, glass-ceramic, or other transparent material, and the term “transparent” as used herein means that the workpiece has linear light absorption of less than 20% per mm of material depth for a specified pulsed laser wavelength. In embodiments, the transparent workpiece has linear light absorption of less than 10% per mm of material depth for a specified pulsed laser wavelength, or less than 1% per mm of material depth for a specified pulsed laser wavelength. Unless otherwise specified, the transparent workpiece has linear light absorption of less than about 20% per mm of material depth. The transparent workpiece may have a depth (e.g., thickness) of about 50 microns (μm) to about 10 mm (e.g., about 100 μm to about 5 mm, or about 0.5 mm to about 3 mm). The transparent workpiece may comprise a glass workpiece formed from a glass composition such as borosilicate glass, soda-lime glass, aluminosilicate glass, alkali aluminosilicate, alkaline earth aluminosilicate glass, alkaline earth boro-aluminosilicate 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 thermal tempering before or after laser treatment of the transparent workpiece. In some embodiments, the glass may be ion-exchangeable or ion-exchangeable so that the glass composition may undergo ion exchange or undergo ion exchange for glass strengthening before or after laser treatment of the transparent workpiece. For example, the transparent workpiece may be Corning Gorilla, available from Corning Incorporated in Corning, New York. ®It may include ion-exchangeable or ion-exchangeable glasses, such as glass (e.g., Code 2318, Code 2319, and Code 2320). Additionally, such ion-exchangeable or ion-exchangeable glasses may have a coefficient of thermal expansion (CTE) of about 6 ppm / °C to about 10 ppm / °C. Other exemplary transparent workpieces are available from Corning Incorporated, Corning, New York, EAGLE XG ® and CORNING LOTUST M It may include. Furthermore, the transparent workpiece may include other components that are transparent to the wavelength of the laser, such as glass ceramic or crystals like sapphire or zinc selenide.

[0092] In the ion exchange process, ions in the surface layer of a transparent workpiece are replaced by larger ions having the same valence or oxidation state, for example, by partially or completely immersing the transparent workpiece in an ion exchange bath. As smaller ions are replaced by larger ions, a compressive stress layer extends from one or more surfaces of the transparent workpiece to a specific depth within the transparent workpiece (referred to as layer depth). The compressive stress is balanced by a tensile stress layer (referred to as central tension) so that the net stress of the glass sheet becomes zero. When compressive stress is formed on the surface of the glass sheet, the glass becomes stronger and resistant to mechanical damage, thereby mitigating catastrophic breakage of the glass sheet from scratches 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 with monovalent cations other than alkali metal cations, such as Ag+, Tl+, Cu+, etc.

[0093] As used herein, the term “quasi-non-diffracting beam” is used to describe a laser beam having low beam divergence, as mathematically described below. In particular, in the embodiments described herein, a laser beam is used to form the contours of defects. The laser beam has an intensity distribution I(X,Y,Z), as illustrated in the drawings, where Z is the beam propagation direction of the laser beam, and X and Y are directions orthogonal to the beam propagation direction. The X-direction and Y-direction are also referred to as cross-sectional directions, and the XY plane is referred to as the cross-sectional plane. The coordinates and directions X, Y, and Z are also referred to herein as x, y, and z, respectively. The intensity distribution of the laser beam in the cross-sectional plane may be referred to as the cross-sectional intensity distribution.

[0094] A quasi-non-diffracting laser beam can be formed by colliding a diffracting laser beam (e.g., a Gaussian beam) into, onto, and / or through a phase-changing optical element, such as an adaptive phase-changing optical element (e.g., a spatial light modulator, an adaptive phase plate, a deformable mirror, etc.) or a static phase-changing optical element (e.g., a static phase plate, an aspherical optical element such as an axicon, etc.), in order to change the phase of the beam, reduce beam divergence, and increase the Rayleigh range mathematically defined below. Examples of quasi-non-diffracting beams include the Gaussian-Bessel beam, Airy beam, Weber beam, and Bessel beam.

[0095] Referring to FIGS. 1a through 1d, the pulsed laser beam (112) used to form defects further has an intensity distribution I (X, Y, Z), as shown in the drawings, where Z is the beam propagation direction of the pulsed laser beam (112), and X and Y are directions orthogonal to the propagation direction. The X-direction and Y-direction are also referred to as cross-sectional directions, and the XY plane is also referred to as a cross-sectional plane. The intensity distribution of the pulsed laser beam (112) in the cross-sectional plane may be referred to as a cross-sectional intensity distribution.

[0096] A pulsed laser beam (112) at a beam spot (114) or other cross section may include a quasi-non-diffracting beam, for example, a beam having low beam divergence as mathematically defined below, by propagating the pulsed laser beam (112) through a phase-changing optical element (120) as described in more detail below for the optical assembly (100) illustrated in FIG. 2 (e.g., outputting a pulsed laser beam (112) such as a Gaussian beam using a beam source (110). Beam divergence represents the magnification ratio of the beam cross section in the beam propagation direction (i.e., Z direction). As used herein, the phrase “beam cross section” refers to a cross section of the pulsed laser beam (112) that follows a plane perpendicular to the beam propagation direction of the pulsed laser beam (112), for example, along the XY plane. One exemplary beam cross section discussed herein is a beam spot (114) of the pulsed laser beam (112) projected onto a transparent workpiece (160).

[0097] The length of the laser beam focal line generated from the quasi-non-diffracted beam is determined by the Rayleigh range of the quasi-non-diffracted beam. In particular, the quasi-non-diffracted beam defines a laser beam focal line (113) having a first endpoint and a second endpoint, each defined by position, wherein the quasi-non-diffracted beam propagates a distance from the beam waist equal to the Rayleigh range of this quasi-non-diffracted beam. The length of the laser beam focal line corresponds to twice the Rayleigh range of the quasi-non-diffracted beam. A detailed description of the formation of quasi-non-diffracted beams and the determination of their lengths, including a generalization of the description of such beams for asymmetric (such as non-axial) beam cross-sectional profiles, is provided in U.S. Provisional Application No. 62 / 402,337 and Dutch Patent Application No. 2017998, which are incorporated by reference in their entirety.

[0098] The Rayleigh range corresponds to the distance at which the dispersion of a laser beam doubles (for the dispersion at the beam waist position as defined in Section 3.12 of ISO 11146-1:2005(E)) and is a measure of the divergence of the cross-sectional area of ​​the laser beam. The Rayleigh range can also be observed as the distance along the beam axis at which the peak light intensity observed in the beam's cross-sectional profile decreases to half the value observed at the beam waist position (maximum intensity position) in the beam's cross-sectional profile. A laser beam with a large Rayleigh range has low divergence and expands more slowly with distance in the beam propagation direction than a laser beam with a small Rayleigh range.

[0099] The beam cross-section is characterized by its shape and dimensions. The dimensions of the beam cross-section are characterized by the beam's spot size. In the case of a Gaussian beam, the spot size is 1 / e of the maximum beam intensity. 2 It is often defined as a radius range that decreases. The maximum intensity of a Gaussian beam is the center of the intensity distribution ( x = 0 and y = 0 (orthogonal) or r It occurs at 0 (cylindrical) and the radius range used to determine the spot size is measured relative to the center.

[0100] A beam having a Gaussian intensity profile may be less preferred for laser processing to form defects (172) because, when the available laser pulse energy is focused to a spot size small enough to deform a material such as glass (e.g., a spot size in the micron range such as about 1-5 μm or about 1-10 μm), the beam diffracts severely and diverges significantly over a short propagation distance (low Rayleigh range). To achieve low divergence (high Rayleigh range), it is desirable to reduce diffraction by controlling or optimizing the intensity distribution of the pulsed laser beam. A pulsed laser beam may not diffract or may diffract weakly. Weakly diffracted laser beams include quasi-non-diffracted laser beams. Representative weakly diffracted laser beams include the Bessel beam, Gauss-Bessel beam, Airy beam, Weber beam, and Mathieu beam.

[0101] Non-diffracting or quasi-non-diffracting beams generally have complex intensity profiles, such as decreasing non-monotonicly with respect to radius. Similar to Gaussian beams, the effective spot size For any beam, even a non-axially symmetric beam, the intensity is 1 / e of the maximum intensity. 2 It can be defined as the shortest radial distance in any direction at the radial position of the maximum intensity (r = 0) that decreases. In addition, for an axisymmetric beam The strength is 1 / e of the maximum strength 2 It is the radial distance from the radial position of the maximum intensity (r = 0) at which it decreases. Effective spot size for an axisymmetric beam Rayleigh range based on (Z R The criterion for ) can be specified as a non-diffracting or quasi-non-diffracting beam to form a damage region in Equation (1) below:

[0102] (1)

[0103] Here F D is a dimensionless divergence coefficient having a value of at least 10, at least 50, at least 100, at least 250, at least 500, and at least 1000 in the ranges of 10 to 2000, 50 to 1500, and 100 to 1000. For a non-diffracted beam or a quasi-non-diffracted beam, the distance of Equation (1) at which the effective spot size is doubled (Rayley range) Z R is the expected distance when a conventional Gaussian beam profile is used. F D It is multiplied by. Dimensionless divergence coefficient F D provides a criterion for determining whether the laser beam is quasi-non-diffracting. As used herein, the pulsed laser beam (112) has characteristics of the laser beam F D If equation (1) with a value of ≥10 is satisfied, it is considered to be quasi-non-diffraction. F D As the value of increases, the pulsed laser beam (112) approaches a more nearly complete non-diffraction state.

[0104] Additional information regarding Rayleigh range, beam divergence, intensity distribution, axisymmetric and non-axial beams, and spot size as used herein is also found in the international standards ISO 11146-1:2005(E) titled "Lasers and laser-related equipment—Test methods for laser beam widths, divergence angles and beam propagation ratios—Part 1: Stigmatic and simple astigmatic beams," ISO 11146-2:2005(E) titled "Lasers and laser-related equipment—Test methods for laser beam widths, divergence angles and beam propagation ratios—Part 2: General astigmatic beams," and ISO 11146-3:2004(E) titled "Lasers and laser-related equipment—Test methods for laser beam widths, divergence angles and beam propagation ratios—Part 3: Intrinsic and geometrical laser beam classification, propagation and details of test methods," and their entirety The disclosure is incorporated herein by reference.

[0105] Now, referring to FIGS. 1a through 1c, an exemplary transparent workpiece (160) undergoing laser processing according to the method described herein is schematically illustrated. In particular, FIGS. 1a through 1c is output by a beam source (110), such as a Gaussian beam source, and a beam propagation angle (θ) along a beam path (111). bpA schematic illustration illustrates a laser beam (112) directed toward a transparent workpiece (160), wherein the portion of the laser beam (112) directed toward the transparent workpiece (160) is not orthogonal to the impact surface (162) of the transparent workpiece (160) but instead has an internal beam angle (θ bi It includes a laser beam focus line (113) including ). The laser beam (112) forms a beam spot (114) that is projected onto a collision surface (162) of a transparent workpiece (160), and the transparent workpiece further includes an edge surface (166) and a counter surface (164) that extend between the collision surface (162) and the opposite surface (164).

[0106] The laser beam focus line (113) generates induced absorption within the transparent workpiece (160) to create a defect (172) within the transparent workpiece (160). The laser beam focus line (113) has an internal beam angle (θ bi Because it includes ), the defect (172) formed by induced absorption is such an internal beam angle (θ bi The defect angle (θ) that is equal to or nearly identical to ) d ...includes ). That is, the defects (172) formed in the embodiments described herein include angular defects, where "angular" refers to an angular deviation from the direction perpendicular to the collision surface (162) at the collision location (115). The laser beam focus line (113) is correspondingly angular. Additionally, in the embodiments, the laser beam (112) may be phase-changed by a phase-changing optical element (120). The laser beam (112) has a beam propagation angle (θ bp When the laser beam (112) collides with the collision surface (162) of the transparent workpiece (160) at the inner beam angle (θ bi A laser beam focus line (113) having ) is formed. Additionally, due to the phase change applied by the phase change optical element (120), the laser beam focus line (113) has an internal beam angle (θ) greater than 10°. biWhen having ), the laser beam focus line (113) exhibits quasi-non-diffraction characteristics (mathematically defined in Equation (1) above) within the transparent workpiece (160).

[0107] Referring to FIG. 1d, in the embodiments, a laser beam (112) may be directed in a first orientation into a transparent workpiece (160) along a first beam path (111A). The laser beam (112) forms a first beam spot (114A) that is projected onto a collision surface (162) of the transparent workpiece (160). The laser beam (112) passes through the collision surface (162) at a first collision location (115A) within the first beam spot (114A) in the same process as previously described. The first portion of the laser beam (112) directed toward the transparent workpiece (160) includes a first laser beam focus line (113A) and generates induced absorption to create a first defect segment (172A) within the transparent workpiece.

[0108] In the embodiments, the laser beam (112) may be adjusted (as indicated by the arrow) toward a second orientation into the transparent workpiece (160) along the second beam path (111B). Adjusting the laser beam (112) may include rotating the laser beam (112), moving the laser beam (112) laterally, rotating the laser beam (112) (as shown in FIG. 1d), or a combination thereof. The laser beam (112) forms a second beam spot (114B) that is projected onto the impact surface (162) of the transparent workpiece (160). The laser beam (112) passes through the impact surface (162) at a second impact location (115B) within the second beam spot (114B) in the same process as previously described. The second collision location (115B) may be at the same location as the first collision location (115A) or at a different location. A second portion of the laser beam (112) directed toward the transparent workpiece (160) includes a second laser beam focus line (113B) and generates induced absorption to create a second defect segment (172B) within the transparent workpiece. Each of the first and second laser beam focus lines includes a circular angle spectrum within the transparent workpiece. At least one of the first laser beam focus line (113A) and the second laser beam focus line (113B) includes an internal focus line angle greater than 10° with respect to a plane orthogonal to the collision surface at the collision location, as described in more detail later.

[0109] Similarly, in embodiments, the laser beam (112) may be directed (not shown) toward a third orientation toward the transparent workpiece (160) along a third beam path. The laser beam may be directed in any manner as previously described. The laser beam (112) may form a third beam spot that is projected onto the impact surface (162) of the transparent workpiece (160). The laser beam (112) passes through the impact surface (162) at a third impact location within the third beam spot in the same process as previously described. The third impact location may be at the same location as the first impact location (115A), at the same location as the second impact location (115B), or at a different location. The third portion of the laser beam (112) directed toward the transparent workpiece (160) may include a third laser beam focus line, which creates induced absorption to create a third defect segment within the transparent workpiece. Each of the first, second, and third laser beam focus lines comprises a circular angular spectrum within the transparent workpiece, and at least one of the first laser beam focus line (113A), the second laser beam focus line (113B), and the third laser beam focus line comprises an inner focus line angle greater than 10° with respect to a plane orthogonal to the collision surface at the collision location. In embodiments, at least two of the first laser beam focus line (113A), the second laser beam focus line (113B), and the third laser beam focus line comprise an inner focus line angle greater than 10° with respect to a plane orthogonal to the collision surface at the collision location.

[0110] Now, referring to Fig. 1c, each beam propagation angle (θ bp ), internal beam angle (θ bi ), and defect angle (θ d) is measured with respect to a plane orthogonal to the collision surface (162) at the collision location (115) (i.e., the orthogonal plane (106)). The collision location (115) is a specific location on the collision surface (162) where the laser beam (112) first enters the collision surface (162) and initially makes contact. When the laser beam (112) (including the laser beam focus line (113)) and the transparent workpiece (160) are translated relative to each other, the collision location (115) changes so that the orthogonal plane (106) can change when the collision surface (162) includes variable terrain. Additionally, the beam propagation angle (θ bp ) includes the average angle of the rays of the laser beam (112) striking the collision surface (162) with respect to the orthogonal plane (106). As shown in FIG. 1c, the laser beam (112) striking the collision surface (162) has a maximum beam propagation angle (θ), which is the angle of the rays of the laser beam (112) having the largest angle with respect to the orthogonal plane (106) at the collision surface (162). bmax ), and the minimum beam propagation angle (θ), which is the angle of the ray of the laser beam (112) having the smallest angle at the collision surface (162) with respect to the orthogonal plane (106). bmin Includes ).

[0111] In some embodiments, as shown in FIGS. 1a and 1c, the laser beam (112) may be focused into a laser beam focus line (113) using a lens (132) (which may be located downstream of a phase-changing optical element (120; FIGS. 2a and 2b) that changes the phase of the laser beam (112). In embodiments, the laser beam focus line (113) may further include a plurality of rays. Each individual ray among the plurality of rays has the same phase ( fIt may have a single lens (132). Although a single lens (132) is shown in FIG. 1a and FIG. 1c, some embodiments may include a lens assembly (130) ( FIG. 2a and 2b) comprising a first lens (131) and a second lens (132) and a repetition thereof to focus a laser beam (112) to a laser beam focus line (113). Other standard optical elements (e.g., prisms, beam splitters, etc.) may also be included in the lens assembly (130). As shown in FIG. 1c, the laser beam (112) may have an annular shape when it strikes the lens (132). Although the lens (132) is shown in FIG. 1a as focusing the laser beam (112) to the laser beam focus line (113), other embodiments may use a phase-changing optical element (120) that changes the phase of the laser beam (112) to focus the laser beam (112) to the laser beam focus line (113) as shown in FIG. 1 (i.e., to change the phase of the laser beam (112) and focus it). The laser beam focus line (113) may have a length in the range of about 0.1 mm to about 100 mm or in the range of about 0.1 mm to about 10 mm. Various embodiments may be configured to have a laser beam focus line (113) having a length (l) of about 0.1 mm, about 0.2 mm, about 0.3 mm, about 0.4 mm, about 0.5 mm, about 0.7 mm, about 1 mm, about 2 mm, about 3 mm, about 4 mm, or about 5 mm, for example, about 0.5 mm to about 5 mm.

[0112] In the operation, the laser processing illustrated in FIGS. 1a through 1d further comprises the step of forming a plurality of defects (172) by translating at least one of the laser beam focus line (113, 113A, 113B) and the transparent workpiece (160) relative to each other in a translational direction (101) along a contour (165; i.e., a desired separation line). The plurality of defects (172, 172A, 172B) form a contour (170, 170A, 170B) that can be used to separate the transparent workpiece (160) into a plurality of separated articles (260', 360', 460'; FIG. 9b, 10b, 11b). The defects (172, 172A, 172B) may extend partially or completely through, for example, the depth (i.e., thickness) of the transparent workpiece (160).

[0113] Now, referring to FIGS. 2a and 2b, an internal beam angle (θ) greater than 10° is used in a transparent workpiece (160) using a phase-changing optical element (120). biAn optical assembly (100) for generating a phase-shifted laser beam (112) to form a laser beam focus line (113) having quasi-non-diffraction characteristics in the transparent workpiece (160) is schematically illustrated. The optical assembly (100) includes a beam source (110) for outputting the laser beam (112), a phase-shifting optical element (120), and, in some embodiments, a lens assembly (130). The beam source (110) may include any known or yet-to-be-developed beam source (110) configured to output the laser beam (112), for example, a pulsed laser beam or a continuous wave laser beam. In some embodiments, the beam source (110) may output a laser beam (112) having a wavelength of, for example, 1064 nm, 1030 nm, 532 nm, 530 nm, 355 nm, 343 nm, or 266 nm, or 215 nm. The laser beam (112) used to form defects (172) on the transparent workpiece (160) may be highly suitable for the transparent material at a selected laser wavelength, and the transparent workpiece (160) may be positioned so that the laser beam (112) output by the beam source (110) strikes, for example, a phase-changing optical element (120) and then strikes the lens assembly (130) and then irradiates the transparent workpiece (160). Additionally, the beam path (111) may be extended from the beam source (110) to the transparent workpiece (160) so that when the beam source (110) outputs the laser beam (112), the laser beam may cross the beam path (111) (or propagate along the path).

[0114] In the embodiments illustrated in FIGS. 2a and 2b, the lens assembly (130) comprises two sets of lenses, each set comprising a first lens (131) located upstream of a second lens (132). The first lens (131) can collimate a laser beam (112) within a collimation space (134) between the first lens (131) and the second lens (132), and the second lens (132) can focus the laser beam (112). Additionally, the second lens (132) located downstream of the lens assembly (130) can focus the laser beam (112) onto a transparent workpiece (160) that can be located on the imaging plane (104) of the second lens (132). In some embodiments, the first lens (131) and the second lens (132) each comprise plano-convex lenses. When the first lens (131) and the second lens (132) are each composed of plano-convex lenses, the curvature of the first lens (131) and the second lens (132) may each be directed toward the collimation space (134). In other embodiments, the first lens (131) may include other collimation lenses, and the second lens (132) may include meniscus lenses, aspherical lenses, or other higher-order correction focusing lenses. In operation, the lens assembly (130) can control the position of the laser beam focus line (113) along the beam path (111). Additionally, the lens assembly (130) may include an 8F lens assembly as shown in FIGS. 2a and 2b, a 4F lens assembly comprising a single set of first and second lenses (131, 132), or any other known or yet-to-be-developed lens assembly (130) for focusing a laser beam (112) to a laser beam focus line (113). Furthermore, it should be understood that some embodiments may not include a lens assembly (130) and instead a phase-changing optical element (120) may focus the laser beam (112) to a laser beam focus line (113).

[0115] Referring still to FIGS. 2a and 2b, the phase-changing optical element (120) is positioned within the beam path (111) between the beam source (110) and the transparent workpiece (160), specifically between the beam source (110) and the lens assembly (130), so that the laser beam (112) strikes the phase-changing optical element (120) before the laser beam (112) is focused to the laser beam focus line (113) and directed toward the transparent workpiece (160). In some embodiments, as shown in FIG. 2a, the beam source (110) is positioned so that the beam path (111) is redirected by the phase-changing optical element (120) and the laser beam (112) is reflected from the phase-changing optical element (120) when it strikes the phase-changing optical element (120). In this embodiment, the phase-changing optical element (120) may include an adaptive phase-changing optical element (122), such as a spatial light modulator, a deformable mirror, an adaptive phase plate, or any other optical element configured to actively change the phase change applied by the optical element to the laser beam (112). In other embodiments, as shown in FIG. 2b, the beam source (110) is positioned so that the beam path (111) extends through the phase-changing optical element (120) and crosses the phase-changing optical element (120) when the laser beam (112) strikes the phase-changing optical element (120). In this embodiment, the phase-changing optical element (120) may include a static phase-changing optical element (123), such as an aspherical optical element or a static phase plate. One aspherical optical element used in the embodiments described herein is a rectangular axicon. Accordingly, in some implementation examples, the phase-changing optical element (120) is a refractive optical element, and in other implementation examples, the phase-changing optical element (120) is a reflective optical element.

[0116] In some embodiments, after a laser beam (112) strikes a phase-changing optical element (120), each individual ray among the plurality of rays of the laser beam (112) may have a different angle with respect to the exit surface of the phase-changing optical element (120), which varies according to the azimuth angle at a given radial position. As used herein, "exit surface" refers to the surface of the phase-changing optical element (120) where the ray propagates to a downstream position of the phase-changing optical element (120). In an embodiment where the laser beam (112) is directed downstream without passing through the phase-changing optical element (120) (e.g., FIG. 2a), the exit surface corresponds to the incident surface. In an embodiment where the laser beam (112) is directed downstream after passing through the phase-changing optical element (120) (e.g., FIG. 2b), the exit surface corresponds to the downstream surface of the phase-changing optical element (120). The exit surface may also be referred to herein as the exit surface of the phase-changing optical element (120). As used herein, the “azimuth” of the ray refers to the angular position of the point of intersection between the exit surface of the phase-changing optical element (120) and the ray. In FIGS. 2a and 2b, for example, the exit surface of the phase-changing optical element (120) coincides with the XY plane, and the point of intersection between the beam propagation direction (Z) and the XY plane defines a reference point in the XY plane where the radial position and azimuth are defined. The radial position is the distance from the reference point and corresponds to the distance from the Z-axis. The azimuth extends from 0° to 360° during one rotation in the XY plane relative to the reference point. The direction in the XY plane corresponding to the azimuth 0° is arbitrary and may be selected, for example, to correspond to the X-direction. The ray angle is the angle of the ray relative to the normal from the exit surface.

[0117] A change in the azimuth of the beam angle occurs, for example, when the phase-changing optical element is an ovoid-shaped axicon (described below). In embodiments, the phase-changing optical element may be a sliced ​​ovoid axicon, where the center of the ovoid is removed and an annular ovoid segment acts as the phase-changing optical element. In such embodiments, multiple beams originating at different beam angles from different radial positions of the phase-changing optical element's exit surface converge to form a specific point along the laser beam focus line (113). Due to differences in radial positions, the optical path lengths of individual beams converging (or intersecting at that point) along the laser beam focus line (113) differ. As used throughout this disclosure, the term "optical path length" refers to the distance between the exit surface of the phase-changing optical element (120) and the laser beam focus line (113). These differences in optical path lengths result in phase differences between different rays converging at a specific point along the laser beam focus line (113), and these phase differences cause destructive interference that reduces the intensity of the laser beam focus line (113), thereby suppressing the formation of defects and impairing the ability to cut and separate the transparent workpiece (160) using the laser beam focus line (113). Therefore, in order for the laser beam (112) to exhibit quasi-non-diffraction characteristics in the laser beam focus line (113), each individual ray among the plurality of rays within the laser beam focus line (113) must have the same phase when converging to form each spectrum as described above. f Must have ).

[0118] In the embodiments, to correct the phase of multiple rays converging at a specific point along the laser beam focus line (113), phase correction may be applied to the phase-changing optical element (120). Such phase correction may be constant with respect to the radius distance (position) but may vary depending on the azimuth position (angle). This is because the rays converging and intersecting at a specific point along the laser beam focus line (113) have the same phase ( f Phase correction allows the phase of individual rays of a plurality of rays to be corrected. This is necessary to form a laser beam focus line (113) that exhibits quasi-non-diffraction characteristics without destructive interference and without affecting the shape of each spectrum formed by the intersecting rays. Without being bound by theory, this can produce a small, high-intensity, and symmetric (or nearly symmetric) quasi-non-diffraction beam. If phase correction is not applied by the phase-changing optical element (120) when forming the quasi-non-diffraction beam, the laser beam focus line (113) within the transparent workpiece (160) will be aberrated. In embodiments, the phase-aberrated laser beam focus line may have lower intensity, a larger cross-section, and / or be asymmetric. As such, the phase-aberrated laser beam focus line may not form defects in the glass substrate or may perform worse than the laser beam focus line (113) disclosed herein with phase correction applied.

[0119] To develop phase correction, a vectorized form of Snell's law is used:

[0120] (33)

[0121] Here is the direction of individual rays (perpendicular to the collision surface (162)) in the transparent workpiece (160), and is the direction of individual rays (perpendicular to the collision surface (162)) in air (or another medium immediately upstream of the collision surface (162)), and is the refractive index of the transparent workpiece (160), is the refractive index of air (or another medium immediately upstream of the collision surface (162)), and is an orthogonal plane (106) with respect to the collision surface (162). After the refraction of the ray at the collision surface (162), the polar angle of each individual ray (the angle of refraction of the ray with respect to the transparent workpiece (160), θ) bi (same as) will vary according to the azimuth of the beam at the collision surface (162), and the incident laser beam (112), after passing through (or reflecting from) the phase-changing optical element (120), may no longer be radially symmetric with respect to the central axis or principal axis of the phase-changing optical element (120). The propagation direction of the laser beam refracted from the collision surface (162) into the transparent workpiece (160) will be angular with respect to the incident direction at the collision surface (162) as described below:

[0122] (34)

[0123] Here i surf is the angle between the incident direction of the laser beam and the collision surface (162), and i CoM The polar angle (θ) that defines the direction of beam propagation (also defines the main optical axis) in the transparent workpiece (160) bi It is. To determine phase correction, a specific angle (θ bi A laser beam focus line (113) directed in the direction of the transparent workpiece (160) is conceptualized within the transparent workpiece (160). Such conceptualized laser beam focus line consists of a series of foci, each corresponding to the intersection of a plurality of phase-matched convergent rays emitted from the escape surface of the phase-changing optical element (120) as previously described. Each ray of the conceptualized laser beam focus line is directed in the direction ( It propagates in the direction of the conceptualized laser beam focus line within the transparent workpiece (160) through the collision surface (162) and can be traced back to the medium immediately upstream of the collision surface (162). Equation (33) is the direction for each ray in the medium immediately upstream of the collision surface (162) required to generate the conceptualized laser beam focus line. It can be used to determine the direction. ) is the position (azimuth and radius) of the origin of each ray from the escape surface of the phase-changing optical element (120) and the angle of each ray with respect to the normal of the escape surface of the phase-changing optical element (120). i ref defines ). i ref From, the phase imparted to the laser beam (112) at each point of the escape plane of the phase-changing optical element (120) (e.g., the phase mask (150) shown in FIG. 3b) can be determined from Equation (35), where f egg represents a phase mask defined for a phase-changing optical element (120), and k 0 represents the wavenumber of the beam in air (or another medium between the phase-changing optical element (120) and the collision surface (162), and r represents the distance from the center of the phase mask in radius coordinates:

[0124] (35)

[0125] Phase mask ( f egg The correction implemented in ) is sufficient to generate rays having the same polar angle with respect to the main optical axis within the workpiece. This means that the beam within the workpiece has a circular angle spectrum similar to an aberration-free Bessel beam. These rays will intersect at the laser beam focus line (113) when the impact surface (162) is positioned at the focal point of the lens (132) (or the lowest focal point of the lens assembly (130)). In this situation, the laser beam focus line (113) starts at the impact surface (162). While the rays intersect at the focus line with the same polar angle, the difference in path length due to the different lengths traveled in the air and glass workpieces can form an aberration focus. Additionally, it may be desirable to move the transparent workpiece (160) away from the focal point of the lens (132) along the Z-direction and the impact surface (162). In such embodiments, additional aberrations due to the difference in path length will reduce the maximum intensity of the laser beam focus line (113). Then i ref To perform phase correction for, first, an offset (ζ) representing the distance from the focal point of the lens (132) (where the optical conjugate image of the phase mask is formed) to the collision surface (162) of the transparent workpiece (160) is selected. Then, to correct the phase shift induced by the difference in path length for each ray. f egg Phase correction may be added. To find this correction, and to explain the refraction at the collision surface (162), the optical distance (OD) explaining the refractive index is first found for each ray using Equation (33).

[0126] (36)

[0127] Here d g represents the distance for each ray from a point on the laser beam focus line (113) to the intersection point with the collision surface (162), and d a d represents the distance for each ray from the collision surface (162) to the conjugate image plane of the phase mask from the focal point of the lens (132). Then OD will be an array of optical distances traveled for each ray from the point of intersection to form the laser beam focal line (113) to the conjugate image plane of the phase mask. d g and d a The change in the direction of each ray at the collision surface can be determined using the simple geometric intersection of a line and a plane with Equation (33). The phase offset in radians for each individual ray is given by multiplying the displacement distance by the wavenumber (k0), where k0 = 2π / λ:

[0128] (37)

[0129] Since OD is an array, f OD It represents an array composed of phase corrections for each beam of a beam bundle starting at a point along the laser beam focus line (113).

[0130] f OD The resolution can be controlled by changing the number of rays in the bundle. Additionally, a linear or cubic interpolation function can be used with the final spatial position of each ray to generate a smooth phase mask.

[0131] Accordingly, a corrected phase mask for the phase-changing optical element (120) f mask ) can be generated by the following formula:

[0132] (37)

[0133] In operation, when a laser beam (112) collides with a phase-changing optical element (120), the phase of the laser beam (112) is changed, and the beam propagation angle (θ) bp When directed from ) toward the transparent workpiece (160), a portion of the laser beam (112) containing a laser beam focus line within the transparent workpiece (160) has an internal beam angle (θ) greater than 10°. bi ...includes ) and includes quasi-non-diffraction characteristics within the transparent workpiece (160). For example, internal beam angle (θ bi ) can be 10° to 40°, such as 10° to 35°, 15° to 40°, 20° to 40°, etc., for example, 11°, 12°, 13°, 14°, 15°, 16°, 17°, 18°, 19°, 20°, 21°, 22°, 23°, 24°, 25°, 26°, 27°, 28°, 29°, 30°, 31°, 32°, 33°, 34°, 35°, 36°, 37°, 38°, 39°, etc.

[0134] In the embodiments, after the laser beam (112) strikes the phase-changing optical element (120), a portion of the laser beam focus line (113) may extend outside the transparent workpiece (160) to form an external laser beam focus line (117) located in the free space above (upstream) the transparent workpiece (160) (Fig. 1b). For example, the external laser beam focus line (117) may extend above (upstream) the transparent workpiece by at least 0.01 mm, at least 0.02 mm, at least 0.03 mm, at least 0.05 mm, at least 0.07 mm, at least 0.1 mm, at least 0.2 mm, at least 0.3 mm, at least 0.5 mm, or at least 1 mm.

[0135] Although not limited by theory, after the laser beam (112) is phase-changed by the phase-changing optical element (120), the outer laser beam focus line (117) contains a circular or approximately circular angular spectrum. Similarly, after the laser beam (112) is phase-changed by the phase-changing optical element (120), the laser beam focus line (113) within the transparent workpiece (160) contains a circular or approximately circular angular spectrum. Each of the outer laser beam focus line (117) and the laser beam focus line (113) within the transparent workpiece (160) has a divergence coefficient (F) greater than or equal to 10. D It has a Rayleigh defined by ). In the embodiments, the laser beam (112) has aberrations (i.e., has a non-circular angular spectrum) when the laser beam is upstream of the external laser beam focus line (117) or the formation of the transparent workpiece (160), and when the laser beam (112) is refracted at the impact surface (162) of the transparent workpiece (160), the laser beam (112) exhibits a quasi-non-diffraction characteristic with minimal to no aberrations within the transparent workpiece (160) (i.e., the laser beam focus line (113) within the transparent workpiece (160) has a circular or approximately circular angular spectrum). That is, the phase-changing optical element (120) is configured such that the aberrations imposed on the laser beam (112) by the phase-changing optical element (120) are the inverse of the aberrations imposed on the corresponding aberration-free laser beam (112) incident on the impact surface (162) at the same angle of incidence. Consequently, the aberrations imposed on the laser beam (112) by the phase-changing optical element (120) are reversed when the laser beam (112) is refracted at the collision surface, so that the laser beam (112) within the transparent workpiece (160) is essentially aberration-free and the laser beam focus line (113) has essentially a circular angular spectrum.

[0136] Furthermore, the laser beam focus line (113) illustrated in the drawing extends from the impact surface (162) to the opposing surface (164), but this illustrates only one possible arrangement of the laser beam focus line (113) within and near the transparent workpiece (160). In particular, it should be understood that a portion of the laser beam focus line (113) may extend outside the transparent workpiece (160), such as above (upstream) the impact surface (162), beyond (downstream) the opposing surface (164), beyond the edge surface (166), or a combination thereof. Additionally, if a portion of the laser beam focus line (113) extends outside the transparent workpiece (160), the outer portion of the laser beam focus line (113) [is an inner beam angle (θ) due to Snell's Law. bi It includes an external focus line angle greater than ). Furthermore, it should be understood that the laser beam focus line 113 may start at a location within the transparent workpiece (160) (e.g., between the impact surface (162) and the opposing surface (164)) and end at a location within the transparent workpiece (160) (e.g., between the impact surface (162) and the opposing surface (164)).

[0137] As previously described, the external laser beam focus line (117) may contain a circular or approximately circular angular spectrum, and the laser beam focus line (113) may also contain a circular or approximately circular angular spectrum within the transparent workpiece (160). When the laser beam (112) has a circular angular spectrum in all of free space (i.e., when the external laser beam focus line (117) has a circular angular spectrum) and when the laser beam has a circular angular spectrum within the transparent workpiece (160) (i.e., when the laser beam focus line (113) has a circular angular spectrum within the transparent workpiece (160), two different phase shifts must be applied to each individual part of the laser beam (112). In embodiments, one phase shift referred to as a "circular phase shift" will produce a circular angular spectrum in free space and a rectangular angular spectrum within the transparent workpiece (160). In the embodiments, another phase shift, referred to here as a “rectangular phase shift,” will draw a rectangular angular spectrum in free space and generate a circular angular spectrum within the transparent workpiece (160). In the embodiments, the circular phase shift may be similar to the phase imparted by the circular axicon, and the rectangular phase shift may be similar to the phase imparted by the rectangular axicon.

[0138] FIG. 3a illustrates an example of a rectangular angle spectrum (140), which is applied to a laser beam (112) by a phase-changing optical element (120) such that the laser beam focus line (113) has a specific inner beam angle (θ) greater than 10°. biIt can be ensured that the lens (132) and the lens (132) exhibit essentially aberration-free characteristics at a specific interval between the focal plane and the collision surface (162). The rectangular angle spectrum (140) is designed to correct aberrations that occur when an angled beam (a beam incident on the collision surface (162) at a non-perpendicular angle) is refracted at the collision surface (162), as well as aberrations caused by the previously described path length difference. In particular, the embodiment shown in FIG. 3a illustrates a rectangular angle spectrum (140) including a symmetry axis (142) extending from a first axis end (144) having a first radius of curvature to a second axis end (146) having a second radius of curvature. Furthermore, the first radius of curvature (i.e., the radius of curvature at the first axis end (144)) is different from the second radius of curvature (i.e., the radius of curvature at the second axis end (146)). That is, the shape of the rectangular angular spectrum (140) is a combination of two different ellipses (or egg shapes) with roughly different curvatures, which are colloquially referred to as "egg shapes" in the present invention. Furthermore, the rectangular angular spectrum (140) includes a major axis (148; often referred to as the "long axis") and a minor axis (149; often referred to as the "short axis"), wherein the major axis (148) coincides with the axis of symmetry (142).

[0139] FIG. 3b illustrates a phase mask (150) that can be used by a phase-shifting optical element (120) to phase-shift a laser beam (112) to generate the rectangular angle spectrum (140) shown in FIG. 3a. As shown in FIG. 3b, the phase mask (150) of the laser beam (112) comprises a plurality of phase rings (152) that induce a phase shift extending from 0 to 2π, wherein the phase mask has an x-axis of about 400 pixels and a y-axis of about 300 pixels. Additionally, the phase rings (152) of the portion of the phase mask (150) where x is greater than about 60 pixels and x is less than about 350 pixels each have a circular shape similar to a circular angle spectrum. The phase rings (152) of the phase mask (150) portions where x is less than about 60 pixels and x is greater than about 350 pixels each contain a rectangular shape similar to the rectangular angle spectrum (140). In fact, each phase ring (152) of the phase mask (150) portions where x is less than about 60 pixels and x is greater than about 350 pixels includes a symmetry axis extending from a first axis end having a first radius of curvature to a second axis end having a second radius of curvature, wherein the first radius of curvature is different from the second radius of curvature. However, unlike the rectangular angle spectrum (140), the minor axis of each phase ring (152) of the phase mask (150) coincides with the symmetry axis of each phase ring (152) instead of the major axis.

[0140] Not limited by theory, the rectangular angle spectrum (140) shown in FIG. 3a is a high beam propagation angle (θ) of the laser beam (112) to a planar collision surface (162). biThis represents a specific phase change applied to the laser beam (112) to facilitate the formation of a laser beam focus line (113) exhibiting quasi-non-diffraction characteristics within the transparent workpiece (160) after being directed toward the rectangular angle spectrum (140). When the laser beam (112; e.g., laser beam focus line (113)) is refracted at the impact surface (162) (e.g., at the air-glass interface formed at the impact surface (162)), the laser beam (112; e.g., laser beam focus line (113)) within the transparent workpiece (160) is formed to include a circular or approximately circular angle spectrum. That is, the refraction of the laser beam (112) having a rectangular angle spectrum (140) at the impact surface (162) transforms the angle spectrum of the laser beam (112) into a shape that is less rectangular and more circular within the transparent workpiece (160). For example, in some embodiments, the laser beam (112; e.g., laser beam focus line (113)) within the transparent workpiece (160) may have an angular spectrum having a first radius of curvature and a second radius of curvature similar to the rectangular angular spectrum (140); however, since the angular spectrum of the laser beam (112) within the transparent workpiece (160) is more circular (e.g., less rectangular) than the rectangular angular spectrum (140), the difference between the first radius of curvature and the second radius of curvature of the laser beam (112) within the transparent workpiece (160) is smaller than the difference between the first radius of curvature and the second radius of curvature of the rectangular angular spectrum (140) of the laser beam incident on the impact surface (162) of the transparent workpiece (160).

[0141] Referring again to FIG. 2a, in some implementation examples, the phase change optical element (120) may include an adaptive phase change optical element (122) that applies a phase change to a laser beam (112). The adaptive phase change optical element (122) may be communicably coupled to a controller (121) using one or more communication paths (105) that may include any path for providing power signals, control signals, etc., such as optical fibers, wires, wireless protocols, etc. In operation, the controller (121) may provide a control signal to the adaptive phase change optical element (122) to control a specific phase change (e.g., modulation, phase mask, etc.) applied by the adaptive phase change optical element (122) so that the adaptive phase change optical element (122) applies a specific phase change to the laser beam (112), for example, based on a phase function.

[0142] In some embodiments, the adaptive phase-changing optical element (122) includes a spatial light modulator, which is a transmissive or reflective device capable of spatially modulating the amplitude and / or phase of a laser beam (112) in at least one dimension using a phase mask, for example, the phase mask (150) of FIG. 3B. In operation, the spatial light modulator may apply an optional and configurable phase change to the laser beam based on a control signal from a controller (121). In some embodiments, the adaptive phase-changing optical element (122) includes a deformable mirror, which is a mirror whose surface may be deformed in response to a control signal, such as a control signal from a controller (121), to change the wavefront of the laser beam (112) capable of changing the phase of the laser beam (112). For example, the deformable mirror may be configured to apply a phase mask, such as the phase mask (150). Additionally, in some embodiments, the adaptive phase change optical element (122) includes an adaptive phase plate (or phase plate assembly) capable of applying a selective and controllable phase change to a laser beam (112) in response to a control signal, such as a control signal from a controller (121). For example, the adaptive phase plate may be two or more phase plates movable relative to each other (based on a control signal from the controller (121)) to change the phase change applied to the laser beam (112) based on their relative positions.

[0143] As shown in FIG. 2b, in some embodiments, the phase-changing optical element (120) includes a static phase-changing optical element (123), such as a rectangular axicon (124) illustrated in more detail in FIG. 4a and FIG. 4b. In particular, FIG. 4a shows a front view of the rectangular axicon (124) and FIG. 4b shows a side view of the rectangular axicon (124). The rectangular axicon (124) includes a base portion (125) and a conical portion (126) extending from the base portion (125). The base portion (125) includes a rectangular perimeter (127) having a symmetry axis (128) extending from a first axial end (129a) to a second axial end (129b). At the first axis end (129a), the rectangular perimeter (127) includes a first radius of curvature, and at the second axis end (129b), the rectangular perimeter (127) includes a second radius of curvature different from the first radius of curvature. Additionally, the rectangular axicon (124) includes a major axis (138) and a minor axis (136). In operation, when the laser beam (112) crosses the rectangular axicon (124), the phase change applied to the laser beam (112) results in a laser beam (112) that includes a rectangular angle spectrum (140). Additionally, as illustrated in FIG. 3a and FIG. 4a, the shape of the rectangular perimeter (127) of the rectangular axicon (124) corresponds to the rectangular angle spectrum (140). However, unlike the above rectangular angle spectrum (140), instead of the major axis (138), the minor axis (136) of the rectangular perimeter (127) coincides with the axis of symmetry (128) of the rectangular perimeter (127) of the rectangular axicon (124). Although a single phase-changing optical element (120) is shown in FIG. 2a and FIG. 2b, other embodiments may include a plurality of phase-changing optical elements (120), for example, one phase-changing optical element configured to convert a laser beam into a quasi-non-diffracted beam and another phase-changing optical element configured to form the rectangular angle spectrum (140).

[0144] Although not limited by theory, Snell's Law is the maximum inner beam angle (θ) of the laser beam focus line (113) formed using the technique described above. bi You must understand that it imposes some restrictions on ). Snell's Law is mathematically It is defined as such, and here i 1 is the angle of the incident ray in the first medium (e.g., air), and i 2 is the angle of the light ray in the second medium (e.g., transparent workpiece (160)), and n 1 is the refractive index of the first medium (e.g., air containing a refractive index of about 1), and n 2 is the refractive index of the second medium (e.g., a transparent workpiece (160) which may contain about 1.45 in an embodiment in which the transparent workpiece (160) includes glass). The angle i 1 and i 2 is measured for the normal to the plane of incidence of the light ray (e.g., collision surface (162)). Snell's Law is applied to the angle of light (e.g., internal beam angle (θ)) that can be achieved within the transparent workpiece (160). bi It provides a fundamental limitation on )). This limitation is the critical angle of the transparent workpiece (160). In the case of a transparent workpiece (160) containing a material other than glass, it should be understood that such a critical angle will vary depending on the refractive index of the specific material.

[0145] When the transparent workpiece (160) comprises glass having a refractive index of 1.45, the critical angle is approximately 43.6°. The critical angle is also the internal angle taken by the ray when it contacts the glass at an angle of incidence of nearly 90°. Thus, Snell's law [describes] the internal beam angle (θ) of the laser beam focus line (113). bi ) limits. Also, as shown in FIG. 1c, the laser beam (112) has a maximum beam propagation angle (θbmax ) and minimum beam propagation angle (θ bmin Because it includes ), the laser beam (112) may have a conical shape when it strikes the impact surface (162) of the transparent workpiece (160). In some embodiments, the maximum beam propagation angle (θ) bmax ) and minimum beam propagation angle (θ bmin The difference between (i.e., the cone angle) is in the range of 5° to 30°. For example, if a laser beam (112) strikes the impact surface (162) of a transparent workpiece (160) at a cone angle of 10°, assuming that light can be incident on the transparent workpiece (160) up to a maximum of 90°, the maximum internal beam angle (θ) of the laser beam focus line (113) inside the transparent workpiece (160) bi ) will be 33.6°.

[0146] Although not limited by theory, some reflection of the laser beam (112) may occur at the impact surface (162) of the transparent workpiece (160). For example, the reflection of a ray striking the impact surface (162) at 90° with respect to the normal of the impact position (115) will be 100% for both S-polarized and P-polarized light, and the reflection of a ray striking the impact surface (162) at an angle less than 90° with respect to the normal of the impact position (115) will be less than 100% for both S-polarized and P-polarized light. The laser beam (112) may contain P-polarized or S-polarized light, but P-polarized light may reduce the loss due to reflection. For example, at 85°, the reflectance of S-polarized light is 73%, and the reflectance of P-polarized light is 49%. In operation, additional optical components such as a beam source (110), a phase-changing optical element (120), or a polarizer may be used to S-polarize or P-polarize the laser beam (112). Although not yet limited by theory, if the magnitude of light intensity around each spectrum of the laser beam focus line (113) within the transparent workpiece (160) is non-uniform, the laser beam focus line (113) maintains a circular angular spectrum and quasi-non-diffraction characteristics within the transparent workpiece (160). However, the non-uniform magnitude of light intensity around each spectrum of the laser beam focus line (113) within the transparent workpiece (160) caused by reflection can be compensated by firing the laser beam (112) with non-uniform intensity (i.e., firing the laser beam (112) from the beam source (110), wherein the non-uniform intensity is configured to become uniform around each spectrum when the light is refracted at the collision surface (162) and enters the transparent workpiece (160). An exemplary non-uniform intensity beam that can be used (then converted by a phase-changing optical element (120) into a quasi-non-diffracting beam having a rectangular or otherwise non-uniform angle spectrum) includes an elliptical-Gaussian beam, a top hat beam, or other beams having any intensity profile.

[0147] Now, referring to FIG. 1a and FIG. 5a through 7c, in embodiments, the laser beam may comprise at least a first set of rays (510) and a second set of rays (520), wherein each of the first set of rays (510) and the second set of rays (520) is independently modified by different parts of a phase mask or phase-changing optical element (120). The first set of rays (510) and the second set of rays (520) are radially distinguished from one another as shown in FIG. 5a through 5c. Except for normal incidence, the phase characteristics implied to each set of rays are such that the beam can be aberrated in free space and un-aberrated upon refraction into a transparent workpiece (160). Since strict reversal of such aberrations occurs only at a specific angle of incidence, the desired angle of incidence at which such aberrations are reversed can be programmed through the configuration of the phase mask. In the embodiments, only one of the first set of rays (510) and the second set of rays (520) contains a circular angular spectrum within the transparent workpiece (160). That is, only one set of rays will contain a circular angular spectrum within the transparent workpiece (160) at any given angle. For example, the first set of rays (510) at a given angle ( k If the circular angle spectrum is included in ), the second set of rays (520) is angle ( k ) will not include a circular angle spectrum. Conversely, the second set of rays (520) given an angle ( j If the circular angle spectrum is included in ), the first set of rays (510) is angle ( j It will not include the circular angle spectrum at ). Similarly, at other given angles ( i Regarding ), neither the first set of rays (510) nor the second set of rays (520) will contain a circular angle spectrum. In such an example, the laser beam is angle ( kWhen directed from ) toward the transparent workpiece (160), the first set of rays (510) includes a circular angle spectrum and converges to form a first laser beam focus line (113A) as previously described. However, the laser beam at an angle ( j Unless the transparent workpiece (160) is directed toward the ), the second set of rays (520) will remain aberrated, will not contain a circular angle spectrum, and will not converge to form the second laser beam focus line (113B) as previously described. Therefore, the second laser beam focus line (113B) is at an angle ( j It will not be formed as ), and by the first laser beam focus line (113B) at an angle ( j Defects will not be generated at ) Similarly, the laser beam at an angle ( j When directed toward the transparent workpiece (160) at an angle, the second set of rays (520) includes a circular angle spectrum and converges to form the second laser beam focus line (113B) as previously described. However, the laser beam at an angle ( j Unless the transparent workpiece (160) is directed toward the ), the first set of rays (510) will remain aberrated, will not contain a circular angle spectrum, and will not converge to form the first laser beam focus line (113A) as previously described. Therefore, the first laser beam focus line (113A) is at an angle ( k It will not be formed as ), and by the first laser beam focus line (113A) at an angle ( k A defect will not be generated by ). Although this concept is described with two sets of rays, this concept is intended to be applied to any number of sets of rays, such as three sets of rays, four sets of rays, or more.

[0148] In embodiments, the first set of rays (510) and the second set of rays (520) can form segments (540A and 550A) as shown in FIG. 5a. For example, the first set of rays (510) can define a first segment (540A; an exemplary segment having an annular shape) of the laser beam (112) and the second set of rays (520) can define a second segment (550A; an exemplary segment having a circular shape) of the laser beam (112). In embodiments, the average radius (r2) of the second segment (550A) may be smaller than the average radius (r1) of the first segment (540A), which means that the second segment (550A) is located within the first segment (540A). In other embodiments, as shown in FIG. 5b, the average radius (r2) of the second segment (550B; an annular segment defined by the second ray set (520)) may be larger than the average radius (r1) of the first segment (540B; a circular segment defined by the first ray set (510), which means that the first segment (540B) is located within the second segment (550B). In embodiments, the first ray set (510) may include a portion of the second ray set (520), or the second ray set (520) may include a portion of the first ray set (510).

[0149] In implementation examples, to calculate the required lengths of r1, r2, and r3, when phase correction is calculated, the origin of each ray traced from the laser beam focus line is an array (Z origin Can be recorded in ). Z origin can be changed for each ray set, and Z origin To determine, trace each ray and record the distance. This can be recorded, for example, as the depth below or above the collision surface (162), the distance from the axicon (124), or the Z-coordinate of the origin of each ray. Radii r1, r2 and r3 are Z origin It becomes an isocurve of Z origin The final position of each ray in the phase mask can be used directly or interpolated. An example of this can be seen in Fig. 6a, where three phase masks (generating the same Bessel beam at the same angle within the transparent workpiece) (151A, 151B, and 151C) are shown. Computer simulations were used to change the radius of the phase mask by propagating the beam in the reverse direction. In a similar manner, Z origin It may be modified to create empty spaces between phase masks, ensure that there is no overlap between phase masks, control the order of phase masks, or control the distance between the transparent workpiece (160) and the phase masks. For example, referring still to FIG. 6a, to form a laser beam focus line (113) within the transparent workpiece using phase mask (151A), the transparent workpiece must be positioned relatively closer to the phase mask (151A) than when phase mask (151B) or phase mask (151C) is used. Similarly, to form a laser beam focus line (113) within the transparent workpiece using phase mask (151C), the transparent workpiece must be positioned relatively further from the phase mask (151C) than when phase mask (151A) or phase mask (151B) is used. Each phase mask (151A, 151B, 151C) generates the same Bessel beam at the same angle within the transparent workpiece (160), but the distance between the transparent workpiece (160) and the phase mask is different.

[0150] As previously described, only one of the first set of rays (510) and the second set of rays (520) has a circular angular spectrum within the transparent workpiece (160). This means that one of the first set of rays (510) and the second set of rays (520) forms an aberration laser beam. In embodiments, the second set of rays (520) may form an aberration beam, or the first set of rays (510) may form an aberration beam. Specifically, referring to FIG. 5a and FIG. 7a, in embodiments where the average radius (r2) of the second segment (550A) is smaller than the average radius (r1) of the first segment (540A) and the second set of rays (520) forms an aberration laser beam, the first set of rays (510) may form a first portion (113A1) of the laser beam focus line (113). In embodiments, the first portion (113A1) of the laser beam focus line (113) formed by the first set of rays (510) may include an internal focus line angle (α1) of 0° to 10° or 170° to 180° with respect to the orthogonal plane (106) for the opposing surface (164). The first portion (113A1) of the laser beam focus line (113) starts at the origin (710) within the transparent workpiece (160). As used throughout this disclosure, the term “origin” refers to the origin of the induced absorption region for at least a portion of the laser beam focus line (113). Such an induced absorption region controls the location and length of the defect formed by the process disclosed herein. Thus, the “origin” defined herein may ultimately be the origin for at least a portion of the defect within the transparent workpiece (160). For a fixed position of the transparent workpiece (160) for a fixed optical system, the position of the origin (710) is controlled by the diameter of the second set of rays (520); a larger diameter positions the origin (710) further from the collision surface (162).

[0151] The second set of rays (520) can be aligned to form a second part (113B1) of a laser beam focus line (113) that extends from the collision surface (162) to the origin (710) in the direction of beam propagation, when the second set of rays (520) has a circular angle spectrum within the transparent workpiece (160) and does not form an aberration laser beam.

[0152] In embodiments where the average radius (r2) of the second segment (550A) is smaller than the average radius (r1) of the first segment (540A) and the first set of rays (510) forms an aberration laser beam, the second set of rays (520) may form a second portion (113B1) of a laser beam focus line (113) that extends to the origin (710) in a direction defined by the inner focus line angle (β1). The laser beam focus line (113B1) may start upstream or downstream of the collision surface (162). The average radius (r1) of the first segment (540A) controls the length of the laser beam focus line (113B1); a larger aperture leads to a longer laser beam focus line (113B1). The laser beam focus line (113B1) may include an internal focus line angle (β1) greater than 10° and less than 80° or greater than 100° and less than 170° with respect to the orthogonal plane (106) with respect to the collision surface (162).

[0153] Specifically, referring to FIG. 5b and FIG. 7b, in other embodiments, a first set of rays (510) may define a first segment (540B) of a laser beam (112) and a second set of rays (520) may define a second segment (550B) of a laser beam (112), wherein the average radius (r2) of the second segment (550B) may be larger than the average radius (r1) of the first segment (540B), which means that the first segment (540B) is located within the second segment (550B). In embodiments where the average radius (r2) of the second segment (550B) is greater than the average radius (r1) of the first segment (540B) and the second set of rays (520) forms an aberration laser beam, the first set of rays (510) may form a laser beam focus line (113A2) extending from the impact surface (162) to, upstream from, or downstream from, a termination point (720) within the transparent workpiece (160). As used throughout this disclosure, the term “termination point” refers to the termination point of the induced absorption region for at least a portion of the laser beam focus line (113). Similar to the origin described above, the “termination point” defined herein may ultimately be a termination point for at least a portion of the defect within the transparent workpiece (160). The second beam set (520) may be configured by a phase-changing optical element (120) to form a second part (113B2) of a laser beam focus line (113) that extends beyond the end point (720) in a direction defined by an internal focus line angle (β2), when the second beam set (520) has a circular angle spectrum within the transparent workpiece (160) and does not form an aberration laser beam.In the embodiments, the first portion (113A2) of the laser beam focus line (113) formed by the first set of rays (510) may include an internal focus line angle (α2) of 0° to 10° or 170° to 180° with respect to the plane (106) orthogonal to the collision surface (162).

[0154] In embodiments where the average radius (r2) of the second segment (550B) is greater than the average radius (r1) of the first segment (540B) and the first set of rays (510) forms an aberration laser beam, the second set of rays (520) may form a second part (113B2) of a laser beam focus line (113) that extends beyond the end point (720) in a direction defined by an internal focus line angle (β2). The laser beam focus line (113B2) may extend partially, to the end, or beyond the opposing surface (164). The laser beam focus line (113B2) may include an internal focus line angle (β2) greater than 10° and less than 80° or greater than 100° and less than 170° with respect to the orthogonal plane (106) for the collision surface (162).

[0155] Specifically, referring to FIG. 5c, FIG. 6b and FIG. 7c, the laser beam (112) may include a first set of rays (510), a second set of rays (520), and a third set of rays (530) as shown in FIG. 5c. In embodiments, the first set of rays (510), the second set of rays (520), the third set of rays (530), or a combination thereof may form an aberration laser beam. In embodiments, as shown in FIG. 5c, the first set of rays (510), the second set of rays (520), and the third set of rays (530) may form a first segment (540C; an exemplary circular segment), a second segment (550C; an exemplary annular segment), and a third segment (560C; an exemplary annular segment). In the embodiments, the average radius (r1) of the first segment (540C) may be smaller than the average radius (r2) of the second segment (550C), and the average radius (r2) of the second segment (550C) may be smaller than the average radius (r3) of the third segment (560C). This means that the first segment (540C) is located within the second segment (550C), and the second segment (550C) is located within the third segment (560C). In the embodiments, the second ray set (520) may include a portion of the third ray set (530), or the third ray set (530) may include a portion of the second ray set (520).

[0156] Referring further to FIGS. 5c, FIGS. 6b and FIGS. 7c specifically, an exemplary phase mask (150) for such an implementation example is shown in FIG. 6b, where the phase mask segment (150A) corresponds to a first set of rays (510) forming a first segment (540C), the phase mask segment (150B) corresponds to a second set of rays (520) forming a second segment (550C), and the phase mask segment (150C) corresponds to a third set of rays (530) forming a third segment (560C).

[0157] In the embodiments, the first set of rays (510) may be configured by a phase-changing optical element (120) to form a first portion (113A3) of a laser beam focus line (113) where the first set of rays (510) terminates at an end point (720). The third set of rays (530) may be configured by a phase-changing optical element (120) so that, when the third set of rays (530) has a circular angle spectrum within the transparent workpiece (160) and does not form an aberration laser beam, the third set of rays (530) extends beyond the end point (720) in the beam propagation direction and forms a third portion (113B3) of a laser beam focus line (113) where it terminates at a second end point (730) within the transparent workpiece (160). The second set of rays (520) may be configured by a phase-changing optical element (120) such that, when the second set of rays (520) has a circular angle spectrum within the transparent workpiece (160) and does not form an aberration laser beam, the second set of rays (520) forms a third part (113C) of a laser beam focus line (113) that extends beyond a second end point (730) in the direction of beam propagation. The laser beam focus line (113A3) may include an inner focus line angle (α3) greater than 10° and less than 80° or greater than 100° and less than 170° with respect to the orthogonal plane (106) with respect to the collision surface (162). The laser beam focus line (113B3) may include an inner focus line angle (β3) greater than 0° and less than 10° or greater than 170° and less than 180° with respect to the orthogonal plane (106) with respect to the collision surface (162). The laser beam focus line (113C) may include an inner focus line angle (γ) greater than 10° and less than 80° or greater than 100° and less than 170° with respect to the orthogonal plane (106) with respect to the collision surface (162).Switching between the second and third sets of rays (520, 530) so that the third set of rays (530) forms a third part (113B3; the middle part as shown in FIG. 7c) of the laser beam focus line (113) and the second set of rays (520) forms a second part (113C; the lower part as shown in FIG. 7c) of the laser beam focus line (113) may be desirable to avoid undesirable damage to the impact surface (162) of the transparent workpiece (160). For example, when the second set of rays (520) forms the third part (113B3) and the third set of rays (530) forms the second part (113C), the intensity of the first set of rays (510) may be sufficiently large to damage the glass. Intensities sufficient to damage glass can correspond to burst count, glass type, focal spot size, and pulse width, among other variables. Without limitation as examples, the damage threshold for glass is 1 to 2 terawatts per square centimeter (TW / cm). 2 ) may be. In implementation examples, a typical laser beam focus line (113) is 4 TW / cm 2 , 5 TW / cm 2 , or 6 TW / cm 2 It may have a greater intensity. In implementation examples, such intensity may be greater than a damage threshold and may cause only Type 1 damage. Type 1 damage changes the refractive index of the glass without cracking the glass. To prevent the glass from being damaged by carelessness, it may be advantageous to switch the second and third sets of rays (520, 530) so that the first set of rays (510) is not located right next to the second set of rays (520).

[0158] Now, referring to FIGS. 1a through 4b, a laser beam (112) can be used to form high-angle defects (172) on a transparent workpiece (160) when the impact surface (162) includes a planar terrain. However, in other embodiments, the impact surface (162) may include a non-planar terrain, such as a curved terrain, a jagged terrain, or a surface having any non-planar terrain. When the impact surface (162) includes a non-planar terrain, a phase-shifting optical element (120) may apply a phase change to the laser beam (112) so that the laser beam (112) directed upstream and / or incident on the impact surface (162) (e.g., in free space) includes a non-circular angle spectrum corresponding to the non-planar terrain, such that a portion of the laser beam focus line (113) within the transparent workpiece includes a circular angle spectrum and exhibits quasi-non-diffraction characteristics.

[0159] As an example, if the collision surface (162) is a consistent non-planar surface (e.g., a consistent curved surface), the phase change may be applied by an adaptive phase change optical element (122) or a static phase change optical element (123). For example, such a phase change may be applied by a static phase change optical element (123) comprising a base portion and a non-circular axicon having a conical portion extending from the base portion, wherein the base portion comprises a non-circular periphery such that the phase change applied to the laser beam (112) by the non-circular axicon forms a non-circular angular spectrum corresponding to the consistent curved terrain of the collision surface (162), such that a portion of the laser beam focus line (113) within the transparent workpiece (160) includes a circular angular spectrum, exhibits quasi-non-diffraction characteristics, and has phase-matched cross rays at each position along the length.

[0160] In some embodiments, the impact surface (162) includes non-planar terrain that is inconsistent. For example, the impact surface (162) may include "variable terrain" which refers to a surface having at least two local terrains having an angle difference of ±10% or more as used herein, where "local terrain" refers to the shape of the surface of a transparent workpiece (160) such as the impact surface (162) at a specific location on the surface. When the collision surface (162) comprises variable terrain, the adaptive phase-changing optical element (122) may apply a phase change to the laser beam (112) such that the laser beam (112) directed upstream and / or incident on the collision surface (162) (e.g., in free space) comprises a portion of the laser beam focus line (113) within the transparent workpiece (160) that comprises a circular angle spectrum, exhibits quasi-non-diffraction characteristics, and has phase-matched cross rays at each position along the length, and comprises any non-circular angle spectrum corresponding to the local terrain at the collision position (115). In particular, the controller (121) may provide a control signal to the adaptive phase-changing optical element (122) to apply a phase change to the laser beam (112) so that the laser beam (112) comprises a non-circular angle spectrum. Furthermore, the controller (121) may apply different phase functions over time to the adaptive phase-changing optical element (122). In particular, the controller (121) can actively change the phase function applied by the adaptive phase-changing optical element (122).

[0161] Referring again to FIGS. 1a through 4b, in the operation, a laser beam (112) can be translated along the contour (165) relative to the transparent workpiece (160) (e.g., in the translational direction (101)) to form a plurality of defects (172) of the contour (170). Orienting or localizing the laser beam (112) toward the transparent workpiece (160) generates induced absorption within the transparent workpiece (160) and each defect angle (θ) greater than 10° d Energy sufficient to break the chemical bonds of the transparent workpiece (160) at a spaced position along the contour (165) is applied to form defects (172) including ). According to one or more embodiments, the laser beam (112) may be translated across the transparent workpiece (160) by the movement of the transparent workpiece (160) (e.g., the movement of the translational stage (190) coupled to the transparent workpiece (160) as shown in FIG. 2a and 2b), the movement of the laser beam (112) (e.g., the movement of the laser beam focus line (113)), or the movement of both the transparent workpiece (160) and the laser beam focus line (113).

[0162] Additionally, when the collision surface (162) of the transparent workpiece (160) includes variable terrain, the laser beam (112) may be translated along the contour (165) from a first collision location including a first local terrain to a second collision location including a second local terrain, and then to a plurality of additional collision locations, each including local terrain, some or all of which may be different from each other. Laser processing of a transparent workpiece (160) having a collision surface (162) having variable terrain may include applying a first phase change to the laser beam (112) using an adaptive phase change optical element (122; e.g., a spatial light modulator) so that the laser beam (112) includes a first non-circular angle spectrum in free space, then directing the laser beam (112) to the transparent workpiece (160) at a first collision position, translating the laser beam (112) from the first collision position to a second collision position, and applying a second phase change to the laser beam (112) using an adaptive phase change optical element (122) so that the laser beam (112) includes a second non-circular angle spectrum in free space, then directing the laser beam (112) to the transparent workpiece (160) at the second collision position.

[0163] Beam propagation angle (θ) bp The first phase change and first non-circular angle spectrum correspond to the first local terrain at the first collision location such that a portion of the laser beam (112) directed toward the transparent workpiece (160) at the first collision location is quasi-non-diffracted and includes a laser beam focus line (113) having an internal beam angle greater than 10°, having phase-matched cross rays at each location along the length. Similarly, the beam propagation angle (θ bpThe second phase change corresponds to the second local terrain such that a portion of the laser beam (112) directed toward the transparent workpiece (160) at the second collision location is quasi-non-diffracted and includes a laser beam focus line (113) having an internal beam angle greater than 10°, having phase-matched cross rays at each location along the length. Accordingly, the laser beam focus line (113) has a defect angle (θ) greater than 10°. d A first defect having ) and a defect angle (θ) greater than 10° d It forms a second defect having ).

[0164] Referring again to FIG. 2a, the optical assembly (100) may further include an imaging system (192) configured to generate image data of a collision surface (162). In some embodiments, the imaging system (192) may include one or more cameras, physical surface probes, laser rangefinders, interferometer systems, wavefront sensors, etc. The imaging system (192) is communically coupled to a controller (121) so that the imaging system (192) can transmit image data of the collision surface (162) to the controller (121), and the controller (121) may instruct an adaptive phase change optical element (122) to apply a specific phase change to a laser beam (112) corresponding to the local terrain of the collision location on the collision surface (162).

[0165] Accordingly, laser processing of a transparent workpiece (160) having a collision surface (162) with variable terrain may further include imaging the collision surface (162) using an imaging system (192) to generate image data of the collision surface (162). Using this image data, the imaging system (192), the controller (121), or other computing device may determine the local terrain of the first collision location and the local terrain of the second collision location and determine a specific phase change, which will form a high-angle quasi-non-diffracting laser beam focus line (113) on the transparent workpiece (160) having phase-matched cross rays at each location along its length. The above method further includes using a controller (121) to instruct an adaptive phase change optical element (122) to apply a first phase change when the laser beam (112) is directed toward the collision surface (162) at a first collision location and to apply a second phase change when the laser beam (112) is directed toward the collision surface (162) at a second location. Furthermore, the image data may be used to determine the terrain of part or all of the collision surface (162), thereby determining multiple local terrains of multiple collision locations.

[0166] Referring again to FIGS. 1a through 4b, the defects (172) can generally be spaced apart from each other by a distance according to the contour (170), such as about 0.1 μm to about 500 μm, for example, about 1 μm to about 200 μm, about 2 μm to about 100 μm, about 5 μm to about 20 μm, etc. For example, the appropriate spacing between the defects (172) may be about 0.1 μm to about 50 μm in the case of a TFT / display glass configuration, for example, about 5 μm to about 15 μm, about 5 μm to about 12 μm, about 7 μm to about 15 μm, or about 7 μm to about 12 μm. In some embodiments, the spacing between adjacent defects (172) may be about 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, etc.

[0167] As illustrated in FIGS. 1a and 1b, a plurality of defects (172) of the contour (170) extend into a transparent workpiece (160) and establish a crack propagation path to separate the transparent workpiece (160) into individual parts along the contour (170). Forming the contour (170) involves translating a laser beam (112) along the contour line (165) toward the transparent workpiece (160) (e.g., in the translation direction (101)) to form a plurality of defects (172) of the contour (170). According to one or more embodiments, the laser beam (112) may be translated across the transparent workpiece (160) by the movement of the transparent workpiece (160), the movement of the laser beam (112) (e.g., the movement of the laser beam focus line (113)), or the movement of both the transparent workpiece (160) and the laser beam (112), for example, using one or more translational stages (190; FIG. 2a and 2b). By translating the laser beam focus line (113) with respect to the transparent workpiece (160), the plurality of defects (172) may be formed on the transparent workpiece (160), and each of the plurality of defects (172) has a defect angle (θ) greater than 10°. d Each includes ).

[0168] A suitable laser wavelength for forming defects (172) is a wavelength at which the combined loss of linear absorption and scattering by the transparent workpiece (160) is sufficiently low. In embodiments, at such wavelengths, the combined loss due to linear absorption and scattering by the transparent workpiece (160) is less than 20% / mm, or less than 15% / mm, or less than 10% / mm, or less than 5% / mm, or less than 1% / mm, where the dimension " / mm" means per millimeter of distance within the transparent workpiece (160) in the beam propagation direction (e.g., Z direction) of the laser beam (112). Representative wavelengths for many glass workpieces are Nd 3+ Includes the fundamental and harmonic wavelengths of (e.g., Nd 3+:YAG or Nd 3+ :YVO 4 The fundamental wavelength is close to 1064 nm, and the higher harmonic wavelengths are close to 532 nm, 355 nm, and 266 nm). Other wavelengths of the ultraviolet, visible, and infrared portions of the spectrum that satisfy the combined linear absorption and scattering loss requirements for a given substrate material may also be used.

[0169] In operation, a laser beam (112) output by a beam source (110) can generate multiphoton absorption (MPA) in a transparent workpiece (160). MPA is the simultaneous absorption of two or more photons of the same or different frequencies that excite a molecule from one state (typically the ground state) to a higher energy electronic state (i.e., ionization). The energy difference between the lower and upper states of the molecule involved is equal to the sum of the energies of the photons involved. MPA, also known as stimulated absorption, can be a second-order or third-order process (or a higher order) that is, for example, several times weaker than linear absorption. This is a nonlinear optical process, as it differs from linear absorption in that the intensity of second-order stimulated absorption can be proportional to, for example, the square of the light intensity.

[0170] To irradiate a transparent workpiece (160) and create a laser beam focus line (113), the perforation step (Figs. 1a and 1b) for creating a contour (170) may utilize a beam source (110; e.g., a pulsed beam source such as an ultrashort pulse laser) in combination with a phase-changing optical element (120), a first lens (131), and a second lens (132). The laser beam focus line (113) may include a quasi-non-diffracting beam such as a Gaussian-Bessel beam or a Bessel beam, as defined above, and may completely or partially perforate the transparent workpiece (160) to form defects (172), each of which has a defect angle (θ) greater than 10° in the transparent workpiece (160) capable of forming the contour (170). d...includes ). In embodiments where the laser beam (112) comprises a pulsed laser beam, the pulse duration of the individual pulse is in the range of about 1 femtosecond to about 200 picoseconds, such as about 1 picosecond to about 100 picoseconds, 5 picoseconds to about 20 picoseconds, etc., and the repetition rate of the individual pulse may be in the range of about 1 kHz to 4 MHz, such as in the range of about 10 kHz to about 3 MHz, or in the range of about 10 kHz to about 650 kHz.

[0171] Now, referring to FIGS. 8a and 8b, in an embodiment comprising a pulsed laser beam in addition to the single-pulse operation at the individual pulse repetition rate described above, the pulses may be generated in pulse bursts (500) of two or more sub-pulses (500A) (e.g., 3 sub-pulses, 4 sub-pulses, 5 sub-pulses, 10 sub-pulses, 15 sub-pulses, 20 sub-pulses, or more, e.g., 1 to 30 sub-pulses per pulse burst (500), or 5 to 20 sub-pulses per pulse burst (500)). Although not limited by theory, a pulse burst is a short, fast group of sub-pulses that generates optical energy interactions (i.e., MPA of the transparent workpiece (160) material) at time scales that are not easily accessible using single-pulse operation. Although not yet limited by theory, energy within a pulse burst (i.e., a group of pulses) is conserved. As an exemplary example, in the case of a pulse burst with an energy of 100 μJ / burst and two sub-pulses, the 100 μJ / burst energy is divided between the two pulses for an average energy of 50 μJ per sub-pulse, and in the case of a pulse burst with an energy of 100 μJ / burst and ten sub-pulses, the 100 μJ / burst is divided into ten sub-pulses for an average energy of 10 μJ per sub-pulse. Furthermore, the energy distribution between the sub-pulses of the pulse burst does not need to be uniform. In fact, in some cases, the energy distribution between the sub-pulses of the pulse burst takes the form of exponential decay, such that the first sub-pulse of the pulse burst contains the most energy, the second sub-pulse of the pulse burst contains slightly less energy, and the third sub-pulse of the pulse burst contains much less energy. However, other energy distributions within individual pulse bursts are also possible, where the precise energy of each sub-pulse can be adjusted to impose different amounts of modification on the transparent workpiece (160).

[0172] Although not yet limited by theory, when defects (172) of one or more contours (170) are formed by a pulse burst having at least two sub-pulses, the force required to separate the transparent workpiece (160) along the contour (170) (i.e., maximum fracture resistance) is reduced compared to the maximum fracture resistance of a contour (170) having the same spacing between adjacent defects (172) in the same transparent workpiece (160) formed using a single pulse laser. For example, the maximum fracture resistance of a contour (170) formed using a single pulse is at least twice as large as the maximum fracture resistance of a contour (170) formed using a pulse burst having two or more sub-pulses. Additionally, the difference in maximum breaking resistance between the contour (170) formed using a single pulse and the contour (170) formed using a pulse burst having two sub-pulses is greater than the difference in maximum breaking resistance between the contour (170) formed using a pulse burst having two sub-pulses and the contour formed using a pulse burst having three sub-pulses. Therefore, the pulse burst can be used to form a contour (170) that is more easily separated than the contour (170) formed using a single pulse laser.

[0173] Referring still to FIG. 8a and FIG. 8b, sub-pulses (500A) within a pulse burst (500) may be separated by durations ranging from about 1 nsec to about 50 nsec, for example, from about 10 nsec to about 30 nsec, such as about 20 nsec. In other embodiments, sub-pulses (500A) within a pulse burst (500) may be separated by durations up to 100 psec (e.g., 0.1 psec, 5 psec, 10 psec, 15 psec, 18 psec, 20 psec, 22 psec, 25 psec, 30 psec, 50 psec, 75 psec, or any range between these). For a given laser, the time separation (T) between adjacent sub-pulses (500A) within a pulse burst (500) p ; FIG. 8b) may be relatively uniform (e.g., within about 10% of each other). For example, in some embodiments, each sub-pulse (500A) within a pulse burst (500) is temporally separated from a subsequent sub-pulse by about 20 nsec (50 MHz). Additionally, the time between each pulse burst (500) may be about 0.25 microseconds to about 1000 microseconds, e.g., about 1 microsecond to about 10 microseconds, or about 3 microseconds to about 8 microseconds.

[0174] In some exemplary embodiments of the beam source (110) described herein, time separation (T b ; FIG. 8b) is about 5 microseconds for a beam source (110) outputting a laser beam (112) having a burst repetition rate of about 200 kHz. The laser burst repetition rate is the time (T) between the first pulse of the burst and the first pulse of the subsequent burst. b It is related to ) (Laser burst repetition rate = 1 / T b). In some embodiments, the laser burst repetition rate may be in the range of about 1 kHz to about 4 MHz. In embodiments, the laser burst repetition rate may be, for example, in the range of about 10 kHz to 650 kHz. The time (T) between the first pulse of each burst and the first pulse of a subsequent burst b ) may be approximately 0.25 microseconds (4 MHz burst repetition rate) to approximately 1000 microseconds (1 kHz burst repetition rate), for example, approximately 0.5 microseconds (2 MHz burst repetition rate) to approximately 40 microseconds (25 kHz burst repetition rate), or approximately 2 microseconds (500 kHz burst repetition rate) to approximately 20 microseconds (50 kHz burst repetition rate). Although the precise timing, pulse duration, and burst repetition rate may vary depending on the laser design, short pulses of high intensity (T d < 20 psec and in some implementation examples, T d It was found that ≤ 15 psec) works particularly well.

[0175] The burst repetition rate may be in the range of about 1 kHz to about 2 MHz, such as about 1 kHz to about 200 kHz. Bursting or generating pulse bursts (500) is a type of laser operation in which the emission of sub-pulses (500A) is in dense clusters of pulse bursts (500) rather than a uniform and steady stream. The pulse burst laser beam may have a wavelength selected based on the material of the transparent workpiece (160) operated so that the material of the transparent workpiece (160) is substantially transparent at that wavelength. The average laser power per burst measured in the material may be about 40 μJ or more per mm of material thickness. For example, in embodiments, the average laser power per burst may be about 40 μJ / mm to about 2500 μJ / mm, or about 500 μJ / mm to about 2250 μJ / mm. Corning EAGLE XG with a thickness of 0.5 mm to 0.7 mm in certain examples ® For a transparent workpiece, a pulse burst of about 300 μJ to about 600 μJ can cut and / or separate the workpiece, which corresponds to an exemplary range of about 428 μJ / mm to about 1200 μJ / mm (i.e., 0.7 mm EAGLE XG ® For glass, 300 μJ / 0.7 mm, 0.5 mm EAGLE XG ® For glass, 600 μJ / 0.5 mm).

[0176] The energy required to deform the transparent workpiece (160) is pulse energy, and the pulse energy may be described in the form of pulse burst energy (i.e., energy contained within a pulse burst (500) in which each pulse burst (500) contains a series of sub-pulses (500A)), or energy contained within a single laser pulse (most may contain bursts). The pulse energy (e.g., pulse burst energy) may be about 25 μJ to about 750 μJ, e.g., about 50 μJ to about 500 μJ, or about 50 μJ to about 250 μJ. For some glass compositions, the pulse energy (e.g., pulse burst energy) may be about 100 μJ to about 250 μJ. However, in the case of a display or TFT glass composition, the pulse energy (e.g., pulse burst energy) may be higher (e.g., about 300 μJ to about 500 μJ, or about 400 μJ to about 600 μJ, depending on the specific glass composition of the transparent workpiece (160).

[0177] The portion of the laser beam (112) directed toward the transparent workpiece (160) may include continuous intensity uniformity. As used herein, the term “continuous intensity uniformity” means that the intensity of the laser beam at any discrete point across the entire portion of the laser beam directed toward the transparent workpiece does not change by more than 50% from the intensity of the laser beam at any second discrete point across the entire portion of the laser beam directed toward the transparent workpiece. In the embodiments described in this disclosure, the continuous intensity uniformity of the laser beam across the entire portion of the laser beam directed toward the transparent workpiece is such that, for any discrete point of the entire portion of the laser beam directed toward the transparent workpiece, the extremum value (i.e., minimum or maximum value) of the laser beam intensity is greater than or equal to about 50% of the laser beam intensity at any second discrete point across the entire portion of the laser beam directed toward the transparent workpiece and less than or equal to about 150%.

[0178] An exemplary intensity distribution of the laser beam focus line (113) according to distance is shown in FIG. 8c. Without being bound by theory, it would be effective to position the impact surface (162) of the transparent workpiece (160) downstream of the formation of the laser beam focus line (113) at a distance of 0.05 mm or more, 0.08 mm or more, 0.10 mm or more, 0.12 mm or more, 0.15 mm or more, 0.18 mm or more, or 0.20 mm or more, so that the laser beam focus line (113) includes the outer laser beam focus line (117) as previously described. Positioning the impact surface (162) of the transparent workpiece (160) downstream from the formation of such a laser beam focus line (113) can cause a greater laser beam (112) intensity at the impact surface (162), ensuring that the internal defect plane is connected to the impact surface (162). Additionally, to ensure that the laser beam focus line (113) exhibits quasi-non-diffraction characteristics in free space upstream of the impact surface (162) of the transparent workpiece (160), the external laser beam focus line (117) may include a circular or approximately circular angular spectrum as previously described.

[0179] Although not limited by theory, the use of a laser beam (112) containing a pulsed laser beam capable of generating pulsed bursts is advantageous for cutting or deforming transparent materials, such as glass (e.g., transparent workpiece (160)). In contrast to using a single pulse with time intervals determined by the repetition rate of a single-pulse laser, using a burst sequence that disperses pulse energy into a sequence of fast pulses within a burst allows access to a larger time scale of high-intensity interaction with the material than is possible with a single-pulse laser. The use of pulsed bursts (as opposed to single-pulse operation) increases the size (e.g., cross-sectional size) of defects (172), which facilitates the connection of adjacent defects (172) when separating the transparent workpiece (160) along one or more contours (170), thereby minimizing unintended crack formation. Additionally, using pulse bursts to form defects (172) increases the randomness of the orientation of cracks extending outward from each defect (172) into the bulk material of the transparent workpiece (160) so that the separation of defects (172) along the contour (170) does not affect or deflect the separation of defects (172) outward from the defect (172), thereby minimizing the formation of unintended cracks as the separation of defects (172) follows the contour (170).

[0180] Referring again to FIGS. 2a and 2b, the optical assembly (100) may be configured to further modify the laser beam (112) by using, for example, the method and system described in U.S. Published Patent Application No. 20180093941A1, the entire contents of which are incorporated herein by reference, so that the cross-section of the laser beam (112) at the impact surface (162) of the transparent workpiece (160) becomes asymmetrical and the cross-section of the laser beam focus line (113) becomes asymmetrical. For example, the beam spot (114) formed by the laser beam focus line (113) at the impact surface (162) of the transparent workpiece (160) may include an asymmetrical beam spot having a long axis and a short axis such that the defects (172) formed using this laser beam focus line (113) include a central defect area formed at the intersection of the long axis and the short axis and one or more radius arms formed in the long axis direction. These defects (172) are formed using a laser beam focus line (113) having a non-axially symmetric beam spot oriented such that the long axis of the beam spot (114) extends along the contour (165), thereby forming defects (172) having radius arms that extend along the contour (165). By controlling the laser beam focus line (113) so that the direction of the radius arm of each defect (172) extends along the contour (165), crack propagation can be better controlled.

[0181] In embodiments where the phase-changing optical element (120) includes an adaptive phase-changing optical element (122), a laser beam focus line (113) having a non-axially symmetric cross section may be formed by changing the phase modulation applied by the adaptive phase-changing optical element (122). Additionally, as described in U.S. Published Patent Application No. 20180093941A1, in embodiments where the phase-changing optical element (120) includes a static phase-changing optical element (123; e.g., a rectangular axicon (124)), a laser beam focus line (113) having a non-axially symmetric cross section may be formed by positioning a radial axicon offset from the beam path (111), blocking a portion of the laser beam (112), or decohering a portion of the laser beam using a phase delay plate.

[0182] Referring again to FIGS. 1a through 4b, in some embodiments, the transparent workpiece (160) may be further acted upon in a subsequent separation step to induce separation of the transparent workpiece (160) along the contour (170) to form a separated transparent article including an angled edge (Figs. 9a through 11b). Such a subsequent separation step may involve using mechanical force, thermal stress-inducing force, or chemical etchant to propagate a crack along the contour (170). A heat source, such as an infrared laser beam, may be used to generate thermal stress to separate the transparent workpiece (160) along the contour (170). Separating the transparent workpiece (160) may involve aiming an infrared laser beam at the contour (170) to induce thermal stress to propagate a crack along the contour (170). In some embodiments, an infrared laser beam may be used to initiate separation, and the separation may be completed mechanically. Without being bound by theory, an infrared laser is a controlled heat source that rapidly increases the temperature of the transparent workpiece (160) at or near the contour (170). This rapid heating can create compressive stress on the transparent workpiece (160) on or adjacent to the contour (170). Because 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 cracks along the contour (170) and through the depth of the transparent workpiece (160), causing complete separation of the transparent workpiece (160) along the contour (170). Without being bound by theory, it is believed that tensile stress can be caused by the expansion of the glass (i.e., a change in density) in the part of the workpiece where the local temperature is higher.

[0183] Infrared lasers suitable for generating thermal stress in glass typically have wavelengths that are easily absorbed by glass, generally ranging from 1.2 µm to 13 µm, for example, from 4 µm to 12 µm. Additionally, the power of the infrared laser beam can be approximately 10 W to approximately 1000 W, for example, 100 W, 250 W, 500 W, 750 W, etc. Furthermore, 1 / e of the infrared laser beam 2 The beam diameter may be approximately 20 mm or less, for example, 15 mm, 12 mm, 10 mm, 8 mm, 5 mm, or 2 mm or less. In operation, the larger 1 / e of the infrared laser beam 2 The beam diameter is the smaller 1 / e of the infrared laser beam. 2 While the beam diameter may facilitate high-precision separation by limiting damage to the transparent workpiece (160) portion near the contour (170), it may also facilitate faster laser processing and more power. Exemplary infrared lasers include carbon dioxide lasers ("CO2 lasers"), carbon monoxide lasers ("CO lasers"), solid-state lasers, laser diodes, or combinations thereof.

[0184] In other embodiments, stress present in the transparent workpiece (160) depending on the type, depth, and material properties (e.g., absorption, CTE, stress, composition, etc.) can cause spontaneous separation along the contour (170) without additional heating or mechanical separation steps. For example, when the transparent workpiece (160) comprises a reinforced glass substrate (e.g., an ion-exchange or thermally reinforced glass substrate), the formation of the contour (170) can induce crack propagation along the contour (170) to separate the transparent workpiece (160).

[0185] Now, referring to FIGS. 9a through 11b, transparent workpieces (260, 360, 460) and resulting separated articles (260', 360', 460') formed from these transparent workpieces are schematically illustrated using the method and system described herein. As one example, FIG. 9a shows defect angles (θ) greater than 10° each. d A schematic side view of a transparent workpiece (260) having a plurality of defects (272) having a plurality of defects (272) is illustrated. The plurality of defects (272; i.e., the outlines of these defects (272)) can be separated to form one or more separated articles (260') each having an angled edge (261), as shown in FIG. 9b.

[0186] As another example, FIG. 10a illustrates a schematic side view of a transparent workpiece (360) comprising a plurality of defects (372), including a first defect (372a) and a second defect (372b). The plurality of defects (372) include a curved contour formed along a curved contour. Both the first defect (372a) and the second defect (372b) extend radially inward, for example, from a collision surface (362; i.e., the upper surface shown in FIG. 10a) to an opposing surface (364; i.e., the lower surface shown in FIG. 10b). Thus, at the collision surface (362), the first defect (372a) and the second defect (372b) are spaced apart by a first spacing distance (D S1 They are spaced apart from each other by the distance of ), and on the opposing surface (364), the first defect (372a) and the second defect (372b) are spaced apart by the first spacing distance (D S1 A second interval distance (D) smaller than ) S2 They are spaced apart from each other by ). In implementation examples where the curve outline is circular, the first spacing distance (D S1) is the diameter of the closed contour at the collision surface, and the second gap distance (DS2) is the diameter of the closed contour at the opposing surface. As shown in FIG. 10b, the closed contour of the defects (372) can be separated to form a separated article (360') having a conical hole (363) defined by an angled edge (361). For example, the closed contour of the defect (372) can be separated using a chemical etching process to form a separated article (360') having a conical hole (363).

[0187] Referring still to FIGS. 10a and 10b, the curved contour of the defects (372) can be formed by rotating the laser beam (112) around the beam path (111) while translating the transparent workpiece (160) and the laser beam (112) relative to each other so that the defects (372) maintain a radially inward orientation relative to the curved contour along the curved contour. Additionally, while the defects (372) are depicted as being oriented radially inward relative to the curved contour, it should be understood that in other embodiments, the defects (372) may be oriented radially outward, for example, by rotating the laser beam (112) around the beam path (111).

[0188] As another example, FIG. 11a illustrates a schematic side view of a transparent workpiece (460) comprising a plurality of defects (472), including a first defect (472a), a second defect (472b), and a third defect (472c). The first defect (472a) extends from the impact surface (462) to the first end of the second defect (472b), the second defect (472b) extends from the end of the first defect (472a) to the end of the third defect (472c), and the third defect (472c) extends from the second end of the second defect (472b) to the edge surface (466). The first defect (472a) can be formed by directing the laser beam focus line (113) from the collision surface (462) to the edge surface (466) at a certain angle, the second defect (472b) can be formed by directing the laser beam focus line (113) from the end of the first defect (472a) to the end of the third defect (472c), and the third defect (472c) can be formed by directing the laser beam focus line (113) from the opposing surface (464) to the edge surface (466) at a certain angle. Additionally, the first defect (472a) may be part of a plurality of first defects (472a) from a first contour, the second defect (472b) may be part of a plurality of second defects (472b) forming a second contour, and the third defect (472c) may be part of a plurality of third defects (472c) forming a third contour. In operation, the first contour of the first defect (472a), the second contour of the second defect (472b), and the third contour of the third defect (472c) may be separated using the embodiments described herein to form a separated article (460') having a chamfered edge (468), as illustrated in FIG. 11b.

[0189] example

[0190] A transparent workpiece was passed under a pulsed laser beam with a wavelength of 1064 nm, pulse energy of 200–800 μJ, a repetition rate of 60 kHz, and a pulse width of 10 ps. The laser has a variable burst mode capable of generating laser pulse bursts at intervals of 12.5 ns between each pulse of the burst. The number of pulses in the burst varies from 1 to 20. The pulsed laser beam was reflected by a spatial light modulator to add a phase of a specially shaped axicon. Then, the laser beam passed through four lenses in a telescopic configuration reduced by a total of approximately 20 times to form a laser beam focus line in contact with the transparent workpiece. The numerical aperture of the last lens (i.e., the lowest lens) was approximately 0.4.

[0191] To puncture and cut the sample, the transparent workpiece was tilted 40° relative to the beam propagation direction and moved in the Y-direction at a speed such that there was an 8-µm pitch between each pulse. The tilt caused an internal focal line angle of 26° inside the glass substrate due to refraction.

[0192] The beam was passed over the sample three times to form a C-chamber (of the type shown in Fig. 11A). For the first pass, the transparent workpiece was tilted 40° relative to the beam propagation direction. For the second pass, the transparent workpiece was tilted 0° relative to the beam propagation direction. For the third pass, the transparent workpiece was tilted 40° relative to the beam propagation direction. Care was taken to ensure that the lower part of the damage was created first, followed by the middle part, and finally the upper part, so that the beam did not need to pass through the previous damage plane. Scattering in these planes can reduce sample damage. Fig. 12 is a cross-sectional image of a glass piece damaged in this manner.

[0193] After damage, the transparent workpiece was separated by applying mechanical and thermal stress to the glass (to create a separated part of the type shown in Fig. 11b). Fig. 13 shows an image of a C-chamfer made using this method, and Fig. 14 shows its surface profile.

[0194] To describe and define the technology of the present invention, it should be noted that a reference to a variable that is a "function" of a parameter or another variable is not intended to indicate that the variable is exclusively a function of the listed parameter or variable. Rather, a reference to a variable that is a "function" of the listed parameter is intended to be open to the possibility that the variable may be a function of a single parameter or multiple parameters.

[0195] As used herein, the term “about” means that the amount, size, formulation, parameters, and other dosages and characteristics are not precise and do not need to be precise, but may be approximate and / or larger or smaller to account for tolerances, conversion factors, rounding, measurement errors, and other factors known to those skilled in the art.

[0196] When the term "about" is used to describe the endpoint of a value or range, it includes the specific value or endpoint associated with it. Whether or not the numerical or range endpoint in the specification cites "about," two implementation examples are described: namely, an implementation example modified by "about" and an implementation example not modified by "about." It should be further understood that each endpoint of the range is significant both in relation to and independently of the other endpoint.

[0197] For example, up, down, right, left, front, back, top, and bottom are determined by referring to the drawn diagram and do not imply absolute directions.

[0198] Unless otherwise specified, the methods described herein are not to be interpreted as the steps being performed in a specific order or as requiring a specific orientation of the device. Accordingly, where a method claim does not actually refer to an order to be followed for the steps, or where a device claim does not actually refer to an order or orientation for individual components, or where otherwise specifically stated in the claim or description, the steps are not limited to a specific order, nor is a specific order or orientation for the components of the device mentioned, and it is not intended for such order or orientation to be inferred in any way. This applies to all possible non-express grounds for interpretation, including: matters of logic regarding the arrangement of steps, flow of operation, order of components, or orientation of components; general meaning derived from grammatical construction or punctuation; and the number or type of embodiments described in the specification.

[0199] The singular forms "one," "one," and "he" as used herein include plural referents unless the context clearly indicates otherwise. Thus, for example, a reference to a "one" component includes a view having two or more such components unless the context clearly indicates otherwise.

[0200] It will be apparent to those skilled in the art that various modifications and alterations may be made to the embodiments described herein without departing from the spirit and scope of the subject matter of the claims. Accordingly, this specification is intended to include modifications and alterations of the various embodiments described herein, provided that such modifications and alterations are within the scope of the claims and their equivalents.

Claims

Claim 1 A method for processing a transparent workpiece (160), wherein the method comprises: a step of directing a laser beam (112) passing through the collision surface (162) of the transparent workpiece (160) at a collision position (115) toward the transparent workpiece (160) in a first orientation along a first beam path (111A); The method includes the step of adjusting the laser beam (112) in a second orientation along a second beam path (111B) so that the laser beam (112) passes through a collision surface (162) at a second collision position (115B) and enters the transparent workpiece (160); the first portion of the laser beam (112) directed toward the transparent workpiece (160) includes a first laser beam focus line (113A) and generates induced absorption to create a first defect segment (172A) within the transparent workpiece (160); the second portion of the laser beam (112) directed toward the transparent workpiece (160) includes a second laser beam focus line (113B) and generates induced absorption to create a second defect segment (172B) within the transparent workpiece (160); and each of the first and second laser beam focus lines (113A, 113B) includes a circular angle spectrum within the transparent workpiece (160); A method for processing a transparent workpiece, wherein at least one of the first laser beam focus line (113A) and the second laser beam focus line (113B) comprises an internal focus line angle greater than 10° with respect to a plane orthogonal to the collision surface (162) at the collision position (115). Claim 2 In claim 1, each of the first and second laser beam focus lines (113A, 113B) is: wavelength λ ; Spot size w o ; and F D Larger Rayleigh range Z R Includes, and here F D A method for processing a transparent workpiece, which is a dimensionless divergence coefficient containing a value of 10 or more. Claim 3 A method for processing a transparent workpiece according to claim 1, wherein each of the first and second laser beam focus lines (113A, 113B) comprises a length defined by a series of points, each point is formed from a plurality of cross rays from the laser beam (112), said cross rays are phase-matched; and the laser beam (112) comprises a first set of rays (510) and a second set of rays (520), said first set of rays (510) defines a first annular segment (540A) of the laser beam (112) and said second set of rays (520) defines a second annular segment (540B) of the laser beam (112), such that at least one of said first set of rays (510) and the second set of rays (520) includes a circular angular spectrum within the transparent workpiece (160). Claim 4 A method for processing a transparent workpiece according to claim 1, further comprising the step of colliding a laser beam (112) with a phase-changing optical element (120) to apply a phase change to the laser beam (112). Claim 5 A method for processing a transparent workpiece according to claim 4, wherein the laser beam (112) comprises a non-circular angle spectrum along a first beam path (111A), a second beam path (111B), or both upstream of a collision surface (162). Claim 6 A method for processing a transparent workpiece according to claim 1, wherein the collision surface (162) comprises a non-planar terrain, and the laser beam (112) comprises a first set of rays (510) and a second set of rays (520), and the method further comprises the step of colliding the laser beam (112) with a phase-changing optical element (120) to apply a phase change to the laser beam (112). Claim 7 In claim 6, at least one of the first set of rays (510) and the second set of rays (520) comprises a circular angle spectrum within the transparent workpiece (160), wherein the first set of rays (510) defines a first annular segment (540A) of the laser beam (112) and the second set of rays (520) defines a second annular segment (540B) of the laser beam (112); the average radius of the first annular segment (540A) is smaller than the average radius of the second annular segment (540B); the first set of rays (510) forms at least a portion of a first laser beam focal line (113A) that terminates at a termination point (720) within the transparent workpiece (160); and the second set of rays (520), wherein the second set of rays (520) comprises a circular angle spectrum within the transparent workpiece (160), the second set of rays (520) terminates in the beam propagation direction. A method for processing a transparent workpiece that is aligned to form at least a portion of a second laser beam focus line (113B) extending beyond a point (720). Claim 8 A method for processing a transparent workpiece according to claim 6, wherein a first set of rays (510) defines a first annular segment (540A) of a laser beam (112) and a second set of rays (520) defines a second annular segment (540B) of a laser beam (112); the average radius of the second annular segment (540B) is smaller than the average radius of the first annular segment (540A); the first set of rays (510) forms at least a portion of a first laser beam focus line (113A) starting from an origin (710) within a transparent workpiece (160); and the second set of rays (520) is aligned such that, when the second set of rays (520) includes a circular angle spectrum within the transparent workpiece (160), the second set of rays (520) forms at least a portion of a second laser beam focus line (113B) extending to the origin (710) in the direction of beam propagation. Claim 9 A method for processing a transparent workpiece (160), the method comprises: a step of colliding a laser beam (112) with a phase change optical element (120) to apply a phase change to the laser beam (112); The method includes the step of directing a laser beam (112) passing through the collision surface (162) of the transparent workpiece (160) at the collision location (115) toward the transparent workpiece (160) in a first orientation along a first beam path (111A); wherein the laser beam (112) comprises a first set of rays (510) and a second set of rays (520), and such that only one of the first set of rays (510) and the second set of rays (520) contains a circular angle spectrum within the transparent workpiece (160), the first set of rays (510) defines a first annular segment (540A) of the laser beam (112) and the second set of rays (520) defines a second annular segment (540B) of the laser beam (112), and the first portion of the laser beam (112) directed toward the transparent workpiece (160) has a first laser beam focus line (113A). Including and generating induced absorption to create a first defect segment (172A) within the transparent workpiece (160), and the first laser beam focus line (113A) is: wavelength λ ; Spot size w o ; and F D Larger Rayleigh range Z R Includes, and here F D is a dimensionless divergence coefficient including a value of 10 or more; a length is defined by a series of points, each point is formed from a plurality of cross rays from a laser beam (112), said cross rays having phase matched, a method for processing a transparent workpiece. Claim 10 A method for processing a transparent workpiece according to claim 9, wherein one of the first set of rays (510) and the second set of rays (520) forms an aberration laser beam (112) within the transparent workpiece (160). Claim 11 A method for processing a transparent workpiece according to claim 10, wherein the average radius of the second annular segment (540B) is smaller than the average radius of the first annular segment (540A); the first set of rays (510) includes a circular angle spectrum within the transparent workpiece (160) and forms at least a portion of the first laser beam focus line (113A) starting from the origin (710) within the transparent workpiece (160); and the second set of rays (520) is aligned such that, when the second set of rays (520) includes a circular angle spectrum within the transparent workpiece (160), the second set of rays (520) forms at least a portion of the second laser beam focus line (113B) extending to the origin (710) in the direction of beam propagation. Claim 12 delete Claim 13 delete Claim 14 delete Claim 15 delete Claim 16 delete Claim 17 delete Claim 18 delete Claim 19 delete Claim 20 delete Claim 21 delete Claim 22 delete Claim 23 delete Claim 24 delete Claim 25 delete Claim 26 delete Claim 27 delete Claim 28 delete Claim 29 delete Claim 30 delete Claim 31 delete Claim 32 delete Claim 33 delete Claim 34 delete Claim 35 delete Claim 36 delete Claim 37 delete Claim 38 delete

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