Method of laser processing coated substrates using top-hat energy distribution

Abstract

A method of separating a coated substrate includes directing an infrared laser beam onto a first surface of the coated substrate. The coated substrate includes a coating layer disposed on a transparent workpiece, a plurality of defects disposed within the coated substrate along a contour line separating a primary area from a dummy area of the coated substrate. The method further includes translating at least one of the coated substrate and the infrared laser beam relative to one another such that the infrared beam spot tracks an oscillating path following an offset line in a direction of translation and oscillating between an inner orbital line and an outer orbital line, the oscillating path is disposed on the dummy area of the coated substrate, and the infrared laser beam imparts thermal energy to the plurality of defects to cause separation of the coated substrate.

Description

[0001] This application claims priority under 35 USC § 119(e) to U.S. Provisional Patent Application Serial No. 63 / 037,126, filed June 10, 2020, which is incorporated by reference in its entirety. BACKGROUND TECHNICAL FIELD

[0003] The present specification generally relates to apparatuses and methods for laser processing coated substrates. TECHNICAL BACKGROUND

[0005] Advances in precision microfabrication and related process improvements made to reduce size, weight, and material costs have facilitated rapid growth of products such as, but not limited to, flat panel displays for touch screens, tablets, smartphones, and televisions. As a result of these advances, ultrafast industrial lasers have become an important tool for applications requiring high precision microfabrication. Laser cutting processes utilizing such lasers are expected to separate substrates in a controlled manner to form negligible debris and cause minimal defects and low subsurface damage to the substrate. Coatings on the surface of the substrate can reduce the efficiency of the laser cutting process. For example, the coating can absorb portions of the laser beam, thereby altering the propagation of the laser beam to interior portions of the substrate. Further, separation of the coated substrate can form an unacceptable amount of debris and can also cause defects or subsurface damage to the separated portions of the substrate.

[0006] Accordingly, there is a need for alternative improved methods for separating coated substrates. SUMMARY

[0007] According to a first aspect of the present disclosure, a method of separating a coated substrate includes directing an infrared laser beam onto a first surface of the coated substrate. The coated substrate includes a coating layer disposed on a transparent workpiece, a plurality of defects disposed within the coated substrate, extending into the coating layer and the transparent workpiece, and disposed along a contour line that separates a primary region of the coated substrate from a dummy region of the coated substrate, and the infrared laser beam projects an infrared beam spot onto the first surface of the coated substrate. The method further includes translating at least one of the coated substrate and the infrared laser beam relative to one another such that the infrared beam spot traces an oscillating path. The oscillating path follows an offset line in a direction of translation and oscillates between an inner orbital line and an outer orbital line, the oscillating path is disposed on the dummy region of the coated substrate, and the infrared laser beam applies thermal energy to the plurality of defects disposed in the coated substrate and causes separation of the coated substrate along the contour line.

[0008] A second aspect of the present disclosure includes the method of the first aspect, wherein the infrared beam spot applies thermal energy to the dummy region of the coated substrate without melting or ablation of the coating layer of the primary region of the coated substrate when tracing the oscillating path.

[0009] A third aspect of the present disclosure includes the method of the first aspect or the second aspect, wherein the infrared beam spot has a Gaussian energy distribution.

[0010] A fourth aspect of the present disclosure includes the method of any of the preceding aspects, wherein the oscillation path follows a linear oscillation, wherein the oscillation path oscillates along a lateral axis that is orthogonal to the offset line, and the offset line is parallel to and offset from the contour line.

[0011] A fifth aspect of the present disclosure includes the method of the fifth aspect, wherein the oscillation path has a plurality of straight portions and a plurality of curved portions, each of the plurality of straight portions extends along the lateral axis between the plurality of curved portions, and each of the plurality of straight portions has a length from 0.5 mm to 1.5 mm, and each of the plurality of curved portions has a radius of curvature from 0.5 mm to 1.5 mm.

[0012] A sixth aspect of the present disclosure includes the method of any of the first aspect through the third aspect, wherein the oscillation path follows a pendulum oscillation, wherein the oscillation path rotationally oscillates between an inner orbit line and an outer orbit line while following the offset line in the translational direction.

[0013] A seventh aspect of the present disclosure includes the method of any of the first aspect through the third aspect, wherein the oscillation path is a zigzag path having angular turns at or between an inner orbit line and an outer orbit line while following the offset line in the translational direction.

[0014] An eighth aspect of the present disclosure includes the method of any of the preceding aspects, wherein the offset line is spaced from the contour line by a distance from 1 mm to 2 mm, the inner orbit line is spaced from the contour line by a distance from 0.5 mm to 1.5 mm, and the outer orbit line is spaced from the contour line by a distance from 1.5 mm to 2.5 mm.

[0015] A ninth aspect of the present disclosure includes the method of any of the preceding aspects, wherein the infrared laser beam is generated by an infrared beam source, and the infrared beam source is coupled to a scanner configured to translate the infrared laser beam such that the infrared beam spot tracks the oscillation path.

[0016] A tenth aspect of the present disclosure includes the method of any of the preceding aspects, wherein the infrared laser beam has a 1 / e 2 diameter in a range from 600 pm to 900 pm.

[0017] An eleventh aspect of the present disclosure includes the method of any of the preceding aspects, wherein the coating layer is a polymer or a metal oxide.

[0018] The twelfth aspect of this disclosure includes a method of any of the foregoing aspects, wherein the transparent workpiece includes borosilicate glass, soda-lime glass, aluminosilicate glass, alkali metal aluminosilicate glass, alkaline earth metal aluminosilicate glass, alkaline earth metal borosilicate glass, fused silica, sapphire, silicon, or gallium arsenide.

[0019] The thirteenth aspect of this disclosure includes a method of any of the foregoing aspects, further comprising forming a plurality of defects in the coated substrate before guiding an infrared laser beam to a first surface of the coated substrate.

[0020] The fourteenth aspect of this disclosure includes the method of the thirteenth aspect, wherein forming multiple defects includes guiding a pulsed laser beam into a coated substrate. The pulsed laser beam forms a focal line extending into the coating layer and the transparent workpiece, the focal line inducing absorption in the coating layer and the transparent workpiece, the induced absorption generating various defects in the coated substrate, and the focal line includes a wavelength λ and a spot size w. o And greater than Rayleigh range Z R , where F D The dimensionless divergence factor includes a value of 10 or greater. The method further includes translating at least one of the coated substrate and the pulsed laser beam relative to each other along a contour line to form a plurality of defects in the coated substrate.

[0021] The fifteenth aspect of this disclosure includes the method of the fourteenth aspect, wherein the coating layer comprises a transmittance of more than 70% per mm of material depth for the wavelength λ of the pulsed laser beam focal line.

[0022] The sixteenth aspect of this disclosure includes the method of the fourteenth or fifteenth aspect, wherein the spacing between adjacent defects in a plurality of defects is about 35 μm or less, each pulse train of the pulsed laser beam has a pulse train energy greater than 500 μJ, and a dimensionless divergence factor F D It has values ​​ranging from 100 to 2000.

[0023] The seventeenth aspect of this disclosure includes the method of the fourteenth or fifteenth aspect, wherein a pulsed laser beam passes through an aspherical optical element before irradiating a coated substrate.

[0024] According to an eighteenth aspect of the present disclosure, a method of separating a coated substrate includes directing an infrared laser beam onto a first surface of a coated substrate. The coated substrate includes a coating layer disposed on a transparent workpiece, a plurality of defects disposed within the coated substrate extending into both the coating layer and the transparent workpiece and disposed along a contour line separating a primary region of the coated substrate from a dummy region of the coated substrate, the infrared laser beam projects an infrared beam spot onto the first surface of the coated substrate, and the infrared beam spot includes an energy distribution in which 20% or less of the fluence of the total energy of the infrared beam spot is less than 80% of the maximum fluence of the infrared beam spot. The method further includes translating at least one of the coated substrate and the infrared laser beam relative to one another such that the infrared beam spot follows an offset line, wherein the offset line is disposed on the dummy region of the coated substrate and offset from the contour line such that an inner region of the infrared beam spot is projected onto the dummy region, and the infrared laser beam applies thermal energy to the plurality of defects disposed on the coated substrate and causes separation of the coated substrate along the contour line.

[0025] A nineteenth aspect of the present disclosure includes the method of the eighteenth aspect, wherein the infrared beam spot applies thermal energy to the dummy region of the coated substrate without melting or ablating the coating layer of the primary region of the coated substrate when following the offset line.

[0026] A twentieth aspect of the present disclosure includes the method of the eighteenth aspect or the nineteenth aspect, wherein at least one of the coated substrate and the infrared laser beam is translated relative to one another such that the infrared beam spot traces an oscillating path that follows the offset line in the direction of translation and oscillates between an inner orbital line and an outer orbital line, and the oscillating path is disposed on the dummy region of the coated substrate.

[0027] A twenty-first aspect of the present disclosure includes the method of any one of the eighteenth aspect through the twentieth aspect, wherein an entire inner region of the infrared beam spot is projected onto the dummy region of the coated substrate.

[0028] A twenty-second aspect of the present disclosure includes the method of any one of the eighteenth aspect through the twenty-first aspect, wherein the infrared laser beam passes through a diffractive optical element prior to impinging on the coated substrate.

[0029] A twenty-third aspect of the present disclosure includes the method of any one of the eighteenth aspect through the twenty-second aspect, wherein 10% or less of the fluence of the total energy of the infrared beam spot is less than 80% of the maximum fluence of the infrared beam spot.

[0030] A twenty-fourth aspect of the present disclosure includes the method of any one of the eighteenth aspect through the twenty-third aspect, wherein 5% or less of the fluence of the total energy of the infrared beam spot is less than 90% of the maximum fluence of the infrared beam spot.

[0031] The 25th aspect of this disclosure includes the method of any one of the 18th to 24th aspects, wherein the offset line is parallel to the contour line.

[0032] The 26th aspect of this disclosure includes the method of any one of aspects 18 to 25, wherein the coating layer is a polymer or a metal oxide.

[0033] The 27th aspect of this disclosure includes the method of any one of the 18th to 26th aspects, wherein the transparent workpiece is borosilicate glass, soda-lime glass, aluminosilicate glass, alkali metal aluminosilicate glass, alkaline earth metal aluminosilicate glass, alkaline earth metal borosilicate glass, fused silica, sapphire, silicon, or gallium arsenide.

[0034] The twentieth aspect of this disclosure includes the method of any one of the eighteenth to twenty-seventh aspects, further comprising forming a plurality of defects in the coated substrate before guiding an infrared laser beam to a first surface of the coated substrate.

[0035] The twenty-ninth aspect of this disclosure includes the method of the twenty-eighth aspect, further comprising, wherein forming a plurality of defects includes guiding a pulsed laser beam into a coated substrate, wherein the pulsed laser beam forms a pulsed laser beam focal line extending into the coating layer and the transparent workpiece, the pulsed laser beam focal line inducing absorption in the coating layer and the transparent workpiece, the induced absorption generating various defects in the coated substrate. The pulsed laser beam focal line includes a wavelength λ and a spot size w. o And greater than Rayleigh range Z R , where F D It is a dimensionless divergence factor including a value of 10 or greater. The method also includes translating at least one of the coated substrate and the pulsed laser beam relative to each other along the contour line to form a plurality of defects in the coating layer.

[0036] The thirtieth aspect of this disclosure includes the method of the twenty-ninth aspect, wherein the coating layer comprises a transmittance of more than 70% per mm of material depth for the wavelength λ of the pulsed laser beam focal line.

[0037] According to a thirty-first aspect of the present disclosure, a method of separating a coated substrate includes directing an infrared laser beam onto a first surface of a coated substrate. The coated substrate includes a coating layer disposed on a transparent workpiece, a plurality of defects disposed within the coated substrate extending into the coating layer and the transparent workpiece and disposed along a contour line separating a primary region of the coated substrate from a dummy region of the coated substrate, and the infrared laser beam projects an infrared beam spot onto the first surface of the coated substrate. The infrared beam spot includes an annular shape. The method further includes translating at least one of the coated substrate and the infrared laser beam relative to one another such that the infrared beam spot follows an offset line, wherein the offset line is disposed on the dummy region of the coated substrate and offset from the contour line such that the infrared beam spot is projected onto the dummy region, and the infrared laser beam applies thermal energy to the coated substrate causing separation of the coated substrate along the contour line.

[0038] A thirty-second aspect of the present disclosure includes the method of the thirty-first aspect, wherein the infrared beam spot applies thermal energy to the dummy region of the coated substrate without melting or ablating the coating layer of the primary region of the coated substrate when following the offset line.

[0039] A thirty-third aspect of the present disclosure includes the method of the thirty-first aspect or the thirty-second aspect, wherein the at least one of the coated substrate and the infrared laser beam is translated relative to one another such that the infrared beam spot traces an oscillating path that follows the offset line in a direction of translation and oscillates between an inner orbital line and an outer orbital line, and the oscillating path is disposed on the dummy region of the coated substrate.

[0040] A thirty-fourth aspect of the present disclosure includes the method of any one of the thirty-first aspect through the thirty-third aspect, wherein the infrared laser beam passes through an aspheric optical element prior to irradiating the coated substrate.

[0041] A thirty-fifth aspect of the present disclosure includes the method of any one of the thirty-first aspect through the thirty-fourth aspect, wherein the infrared laser beam passes through a focusing lens prior to irradiating the coated substrate, the focusing lens includes a focal plane at a focal length of the focusing lens, and the first surface of the coated substrate is positioned relative to the focusing lens such that the focal plane is offset from the coated first surface.

[0042] A thirty-sixth aspect of the present disclosure includes the method of any one of the thirty-first aspect through the thirty-fifth aspect, wherein the infrared laser beam includes a pulsed infrared laser beam, and when the at least one of the coated substrate and the pulsed infrared laser beam is translated relative to one another, the pulsed infrared laser beam impacts the first surface of the coated substrate at impact locations spaced apart along the offset line at a distance from a diameter of the infrared beam spot of ¼ to ½ of the diameter of the infrared beam spot.

[0043] A thirty-seventh aspect of the present disclosure includes the method of any one of aspects thirty-first through thirty-six, further comprising forming a plurality of defects in the coated substrate by directing a pulsed laser beam into the coated substrate prior to directing the infrared laser beam onto the first surface of the coated substrate. The pulsed laser beam forms a pulsed laser beam focal line extending into the coating layer and the transparent workpiece, the pulsed laser beam focal line inducing an absorption in the coating layer and the transparent workpiece, the induced absorption creating individual defects in the coated substrate. The pulsed laser beam focal line comprises a wavelength l, a spot size w o and a Rayleigh range Z > 10 mm R where F D is a dimensionless divergence factor having a value of 10 or greater. The method further comprises translating at least one of the coated substrate and the pulsed laser beam relative to one another along the contour line to form the plurality of defects in the coating layer.

[0044] A thirty-eighth aspect of the present disclosure includes the method of aspect thirty-seven, wherein the coating layer comprises a transmissivity of greater than 70% per mm of material depth for the wavelength l of the pulsed laser beam focal line.

[0045] Additional features and advantages of the processes and systems described herein will be set forth in the detailed description which follows, and in part will be apparent from the description, or can be learned by practice of the embodiments described herein, including the detailed description which follows, the claims, and the appended drawings.

[0046] It is to be understood that both the foregoing general description and the following detailed description describe various embodiments and that they are intended to provide an overview or framework for understanding the nature and character of the claimed subject matter. The accompanying drawings are included to provide a further understanding of the various embodiments, and are incorporated into and constitute a part of this specification. The drawings illustrate the various embodiments described herein and, together with the description, serve to explain the principles and operations of the claimed subject matter. BRIEF DESCRIPTION OF DRAWINGS

[0047] The embodiments set forth in the attached drawings are illustrative and not intended to limit the scope of the subject matter defined by the claims. When read in conjunction with the following detailed description, the attached drawings can serve to explain the principles and operation of the illustrative embodiments. The drawings are not to scale.

[0048] Figure 1A formation of a profile of defects in a coated substrate in accordance with one or more embodiments described herein is schematically depicted;

[0049] Figure 1BAn example pulsed laser beam focal line during processing of a coated substrate is schematically depicted in accordance with one or more embodiments described herein;

[0050] Figure 2 An optical assembly for laser processing using a pulsed laser beam focal line is schematically depicted in accordance with one or more embodiments described herein;

[0051] Figure 3 A graphical depiction of relative intensity versus time of laser pulses within an example pulse train is graphically depicted in accordance with one or more embodiments described herein;

[0052] Figure 4 An optical assembly for laser processing using an infrared laser beam is schematically depicted in accordance with one or more embodiments described herein;

[0053] Figure 5A A cross-section of a coated substrate having a defect formed by laser during laser processing in which an infrared laser beam having a Gaussian intensity profile is directed to the coated substrate in alignment with the defect is schematically depicted in accordance with one or more embodiments shown and described herein;

[0054] Figure 5B A top view of a coated substrate having a series of defects separated using laser processing techniques shown in Figure 5A Figure 5A

[0055] Figure 6 A cross-section of a coated substrate having a defect formed by laser during laser processing in which an infrared laser beam having a Gaussian intensity profile is directed to the coated substrate offset from the defect is schematically depicted in accordance with one or more embodiments shown and described herein;

[0056] Figure 7A Laser processing of a coated substrate using an infrared laser beam having a Gaussian intensity profile along an oscillating path having a linear oscillation is schematically depicted in accordance with one or more embodiments shown and described herein;

[0057] Figure 7B Laser processing of a coated substrate using an infrared laser beam having a Gaussian intensity profile along an oscillating path having a pendulum oscillation is schematically depicted in accordance with one or more embodiments shown and described herein;

[0058] Figure 7C ​​Laser processing of a coated substrate using an infrared laser beam having a Gaussian intensity profile along an oscillating path having a sawtooth oscillation is schematically depicted in accordance with one or more embodiments shown and described herein;

[0059] Figure 7D A relative cumulative fluence applied by a laser infrared laser beam having a Gaussian intensity profile following an oscillating path at a location along a first surface of a coated substrate is graphically depicted in accordance with one or more embodiments shown and described herein;

[0060] Figure 8A An optical assembly in accordance with one or more embodiments shown and described herein is schematically depicted, Figure 4 with the addition of a diffractive optical element for modifying the intensity profile of the infrared laser beam;

[0061] Figure 8B A relative fluence versus radial position of an infrared beam spot having a modified intensity profile projected to a coated substrate is schematically depicted in accordance with one or more embodiments shown and described herein.

[0062] Figure 8C A cross-section of a coated substrate during laser processing using an infrared laser beam having a modified intensity profile in accordance with one or more embodiments shown and described herein is schematically depicted; Figure 8A

[0063] Figure 9A An optical assembly for laser processing using an infrared laser beam comprising an aspherical optical element in accordance with one or more embodiments shown and described herein is schematically depicted;

[0064] Figure 9B A caustic of an infrared laser beam impinging on a coated substrate in accordance with one or more embodiments shown and described herein is schematically depicted; Figure 9A

[0065] Figure 9C A top view of a coated substrate during laser processing using an infrared laser beam in accordance with one or more embodiments shown and described herein is schematically depicted; Figure 9A Figure 9A

[0066] Figure 9D A relative cumulative fluence applied by a laser infrared laser beam to a location of a coated substrate in accordance with one or more embodiments shown and described herein is schematically depicted. Figures 9A-9C

[0067] DETAILED DESCRIPTION​​​​​

[0068] Reference will now be made in detail to embodiments of separating a substrate, such as a coated substrate including a transparent workpiece and a coating layer. The coated substrate includes a primary region and a dummy region. The primary region is to be used as part of the coated substrate for a resulting product, such as a screen or other substrate in a consumer electronic product, while the dummy region is a scrap region. Because the primary region is to be used as a product, it is desirable to separate the primary region from the dummy region while limiting or preventing damage to the primary region. The methods described herein include forming a series of defects in the coated substrate using a pulsed laser beam, and separating the transparent workpiece and the coating layer along the series of defects using an infrared laser beam, the series of defects formed along a boundary between the primary region and the dummy region.

[0069] In particular, the methods described herein use techniques sufficient to induce separation of defects disposed in a coated substrate along a boundary between a primary region and a dummy region in a single process step, directing thermal energy onto the dummy region of the coated substrate. One method described herein includes translating an infrared laser beam along an oscillating path over the dummy region. Another method described herein includes modifying an energy profile of an infrared laser beam to a top hat energy profile, and directing the modified laser beam onto the dummy region. Yet another method described herein includes forming an infrared laser beam into a ring shape, and directing the ring-shaped infrared laser beam onto the dummy region. While the methods and systems are described herein primarily with respect to a coated substrate including a transparent workpiece and a coating layer, it should be understood that these methods and systems are also applicable to the separation of single substrates, such as uncoated transparent workpieces, which can benefit from a reduction in chipping and thermal cracking, and thus a higher release speed. Embodiments of separating a coated substrate using laser processing techniques will be described herein with specific reference to the accompanying drawings. Where possible, the same reference numbers will be used throughout the drawings to indicate the same or similar components.

[0070] As used herein, “laser processing” includes directing a laser beam onto and / or into a substrate, such as a coated substrate including a transparent workpiece along with a coating layer. In some embodiments, laser processing further includes translating the laser beam relative to the coated substrate, for example, along a contour line or other path. Examples of laser processing include using a laser beam to form a contour including a series of defects extending into the transparent workpiece, and using an infrared laser beam to heat both the transparent workpiece and the coating layer. Laser processing can separate the coated substrate along one or more desired separation lines.

[0071] As used herein, a "beam spot" refers to a cross-section (e.g., a beam cross-section) of a laser beam at an impingement location of the laser beam at an impingement surface of a substrate (e.g., a coated substrate). The impingement surface is the surface of the coated substrate on which the laser beam first impinges. The beam spot is the cross-section at the impingement location. In embodiments described herein, a beam spot is sometimes referred to as being "axially symmetric" or "non-axially symmetric." As used herein, axially symmetric refers to a shape that is symmetric or appears the same for any arbitrary angle of rotation about a central axis, and "non-axially symmetric" refers to a shape that is not symmetric for any arbitrary angle of rotation about a central axis. The axis of rotation (e.g., the central axis) is most often taken to be the optical axis (propagation axis) of the laser beam, which is the axis that extends in the direction of beam propagation, which is referred to herein as the z-direction.

[0072] As used herein, "upstream" and "downstream" refer to the relative positioning of two locations or components with respect to a beam source along a beam path. For example, if a first component is closer to a laser source along a path traversed by a laser beam than a second component, the first component is upstream of the second component.

[0073] As used herein, a "pulsed laser beam focal line" refers to a pattern of rays of a laser beam that interact (e.g., intersect) to form a focal region that is elongated in the direction of beam propagation. In conventional laser processing, a pulsed laser beam is tightly focused to a focal point. The focal point is the point of maximum intensity of the pulsed laser beam and is located at a focal plane in a substrate, such as a transparent workpiece. In contrast, in an elongated focal region of a pulsed laser beam focal line, the region of maximum intensity of the laser beam extends beyond a point, to a line aligned with the direction of beam propagation. A pulsed laser beam focal line is formed by converging rays of a laser beam that interact (e.g., intersect) to form a continuous series of focal points aligned with the direction of beam propagation. The pulsed laser beam focal lines described herein are formed using quasi-non-diffracting beams, which are mathematically defined in detail below.

[0074] As used herein, a "contour line" corresponds to a set of intersection points of a laser beam with an incident surface of a substrate (e.g., a coated substrate) resulting from relative motion of the laser beam and the substrate. The shape of a contour line can be linear, angular, polygonal, or curved. A contour line can be closed (i.e., defining a closed area on the surface of the substrate) or open (i.e., not defining a closed area on the surface of the substrate). A contour line represents a boundary along which the substrate is urged to separate into two or more portions. For example, in embodiments discussed herein, a contour line identifies a boundary between a dummy region of a coated substrate and a main region of the coated substrate.

[0075] As used herein, a "contour" refers to a set of defects formed in a substrate (e.g., in a transparent workpiece of a coated substrate) by a laser beam through relative motion of the laser beam and the substrate along a contour line. The defects are spaced along the contour line and are all contained within the interior of the substrate or extend through one or more surfaces to the interior of the substrate. The defects can also extend through the entire thickness of the substrate. Separation of the substrate (e.g., the transparent workpiece) occurs through the connection of defects, such as, for example, through the propagation of cracks.

[0076] As used herein, a "defect" refers to a region of a transparent workpiece that has been modified by a laser beam. The defect includes a region of the transparent workpiece that has a modified refractive index relative to the surrounding unmodified region of the transparent workpiece. Common defects include structurally modified regions in the transparent workpiece produced by a pulsed laser beam focal line, such as void spaces, cracks, scratches, flaws, holes, perforations, densifications, or other deformations. In various embodiments herein, a defect can also be referred to as a defect line or a damage track. The defect or damage track is formed by the interaction of a pulsed laser beam focal line with the transparent workpiece. As more fully described below, the pulsed laser beam focal line is produced by a pulsed laser. The defect at a particular location along the contour line is formed by a single laser pulse at that particular location, a pulse train of sub-pulses at that particular location, or a pulsed laser beam focal line produced by multiple laser pulses at that particular location. Relative motion of the laser beam and the transparent workpiece along the contour line results in the formation of multiple defects that form the contour.

[0077] As used herein, the phrase "transparent workpiece" refers to a workpiece formed of glass, glass-ceramic, or other transparent material, where the term "transparent" as used herein means that the material has a linear optical absorption of less than 20% per millimeter of material depth, such as less than 10% per millimeter of material depth for a specified pulsed laser wavelength, or such as less than 1% per millimeter of material depth for a specified pulsed laser wavelength. Unless otherwise specified, the material has a linear optical absorption of less than about 20% per millimeter of material depth. The transparent workpiece can have a depth (e.g., thickness) of from about 50 micrometers (pm) to about 10 mm, such as from about 100 pm to about 5 mm, or from about 0.5 mm to about 3 mm. The transparent workpiece can include a glass workpiece formed of a glass composition, such as a borosilicate glass, a soda-lime glass, an aluminosilicate glass, an alkali aluminosilicate, an alkaline earth aluminosilicate glass, an alkaline earth boroaluminosilicate glass, fused silica, or a crystalline material (such as sapphire, silicon, gallium arsenide), or combinations thereof. In some embodiments, the glass can be ion-exchangeable, such that the glass composition can undergo ion exchange to achieve glass strengthening prior to or after laser processing of the transparent workpiece. For example, the transparent workpiece can include ion-exchanged glass and ion-exchangeable glass, such as Gorilla® Glass available from Corning Incorporated of Corning, New York. Glass (e.g., numbers 2318, 2319, and 2320). Furthermore, these ion-exchange glasses may have a coefficient of thermal expansion (CTE) ranging from about 6 ppm / °C to about 10 ppm / °C. Other examples of transparent workpieces may include EAGLE, available from Corning Incorporated, Corning, NY. And Corning Lotus TM Glass. Furthermore, the transparent workpiece may include other components that are transparent to the wavelength of laser light, such as glass ceramics or crystals such as sapphire or zinc selenide. Additionally, in the embodiments described herein, a coating layer is applied to the transparent workpiece on which the coated substrate is formed.

[0078] In an ion exchange process, ions in the surface layer of a transparent workpiece are replaced by larger ions with the same valence or oxidation state, for example, by immersing the transparent workpiece partially or completely in an ion exchange bath. Replacing smaller ions with larger ions extends a compressive stress layer from one or more surfaces of the transparent workpiece to a certain depth within the workpiece, known as the layer depth. The compressive stress is balanced by a tensile stress layer (called central tension), resulting in zero net stress in the glass sheet. The compressive stress formed at the surface of the glass sheet strengthens the glass and resists mechanical damage, thus mitigating catastrophic failures caused by defects that do not extend through the layer depth. In some embodiments, smaller sodium ions in the surface layer of the transparent workpiece are exchanged for larger potassium ions. In some embodiments, the ions in the surface layer and the larger ions are monovalent alkali metal cations, such as Li+ (when present in the glass), Na+, K+, Rb+, and Cs+. Alternatively, the monovalent cations in the surface layer can be replaced by monovalent cations other than alkali metal cations (such as Ag+, Tl+, Cu+, etc.).

[0079] As used herein, the term "quasi-non-diffractive beam" is used to describe a laser beam with low beam divergence, as described mathematically below. Specifically, this laser beam is used in the embodiments described herein to form the contour of a defect. The laser beam has an intensity distribution I(X,Y,Z), where Z is the beam propagation direction of the laser beam, and X and Y are directions orthogonal to the beam propagation direction, as depicted in the figures. The X-direction and Y-direction may also be referred to as cross-sectional directions, and the XY plane may be referred to as the cross-sectional plane. In this document, the coordinates and directions X, Y, and Z are also referred to 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.

[0080] A quasi-non-diffracting laser beam can be formed by impinging a diffracting laser beam, such as a Gaussian beam, into, onto, or through a phase-altering optical element, such as an adaptive phase-altering optical element (e.g., a spatial light modulator, an adaptive phase plate, a deformable mirror, etc.), a static phase-altering optical element (e.g., a static phase plate, an aspheric optical element such as an axicon, etc.), to modify the phase of the beam, reduce the beam divergence, and increase the Rayleigh range, as mathematically defined below. Example quasi-non-diffracting beams include Gaussian-Bessel beams, Airy beams, Weber beams, and Bessel beams.

[0081] Reference is made to Figure 1A and Figure 1B and Figure 2 The pulsed laser beam 112 used to form the defects further has an intensity distribution I(X, Y, Z), where Z is the beam propagation direction of the pulsed laser beam 112, and X and Y are directions orthogonal to the propagation direction, as shown. The X- and Y-directions can also be referred to as cross-sectional directions, and the X-Y plane can be referred to as a cross-sectional plane. The intensity distribution of the pulsed laser beam 112 in the cross-sectional plane can be referred to as a cross-sectional intensity distribution.

[0082] The pulsed laser beam 112 at the beam spot 114 or other cross-section can include a quasi-non-diffracting beam, e.g., a beam with low beam divergence as mathematically defined below, by propagating the pulsed laser beam 112 (e.g., using the beam source 110 to output a pulsed laser beam 112 such as a Gaussian beam) through an aspheric optical element 135, as described in more detail below with respect to the optical assembly 100 depicted in Figure 2 Beam divergence refers to the magnification of a beam cross-section in the beam propagation direction (i.e., the Z-direction). As used herein, the phrase “beam cross-section” refers to a cross-section of the pulsed laser beam 112 along a plane perpendicular to the beam propagation direction of the pulsed laser beam 112 (e.g., along the X-Y plane). One example beam cross-section discussed herein is the beam spot 114 of the pulsed laser beam 112 projected onto the coated substrate 120.

[0083] The length of the focal line of the pulsed laser beam generated from the quasi-non-diffractive beam is determined by the Rayleigh range of the quasi-non-diffractive beam. Specifically, the quasi-non-diffractive beam defines a focal line 113 of the pulsed laser beam having a first endpoint and a second endpoint, each endpoint defined by a position where the distance the quasi-non-diffractive beam propagates from the beam waist is equal to the Rayleigh range of the quasi-non-diffractive beam. The length of the laser beam focal line corresponds to twice the Rayleigh range of the quasi-non-diffractive beam. Detailed descriptions of the formation of quasi-non-diffractive beams and the determination of their lengths are provided in U.S. Provisional Application Serial No. 62 / 402,337 and Dutch Patent Application No. 2017998, including descriptions of such beams as asymmetric (e.g., non-axisymmetric) beam cross-sectional profiles, are incorporated herein by reference in their entirety.

[0084] The Rayleigh range corresponds to a distance (as defined in Section 3.12 of ISO 11146-1:2005(E), relative to the beam waist) at which the variance of the laser beam (relative to the beam waist) doubles, and this distance is a measure of the divergence of the cross-sectional area of ​​the laser beam. The Rayleigh range can also be observed as a distance along the beam axis at which the peak intensity observed in the beam cross-sectional profile decays to half the value observed in the beam cross-sectional profile at the beam waist (the location of maximum intensity). Laser beams with a large Rayleigh range exhibit low divergence and expand more slowly with distance in the beam propagation direction compared to laser beams with a small Rayleigh range.

[0085] The beam cross-section is characterized by its shape and size. The size of the beam cross-section is characterized by the beam spot size. For a Gaussian beam, the spot size is often defined as 1 / e of the beam intensity when it decreases to its maximum value. 2 The radial range at the point. The maximum intensity of the Gaussian beam occurs at the center of the intensity distribution (x = 0 and y = 0 (Cartesian) or r = 0 (cylinder)), and the radial range used to determine the spot size is measured relative to the center.

[0086] Beams with Gaussian intensity distributions may be less preferred for laser processing to contour defects because they are highly diffracted and significantly divergent over short propagation distances (low Rayleigh range) when focused to a sufficiently small spot size (e.g., in the micrometer range, such as about 1-5 μm or about 1-10 μm) to allow the available laser pulse energy to modify materials such as glass. To achieve low divergence (high Rayleigh range), it is desirable to control or optimize the intensity distribution of the pulsed laser beam to reduce diffraction. Pulsed laser beams can be non-diffracted or weakly diffracted. Weakly diffracted laser beams include quasi-non-diffracted laser beams. Representative weakly diffracted laser beams include Bessel beams, Gaussian-Bessel beams, Airy beams, Weber beams, and Mathieu beams.

[0087] Non-diffracting or quasi-non-diffracting beams typically have a complex intensity profile, such as those that decrease non-monotonically with respect to radius. By analogy to a Gaussian beam, for any beam (even a non-axially symmetric beam), an effective spot size w o,eff defined as the shortest radial distance from the radial position of maximum intensity (r = 0) at which the intensity decreases to 1 / e of the maximum intensity 2 . Furthermore, for axially symmetric beams, w o,eff is the radial distance from the radial position of maximum intensity (r = 0) at which the intensity decreases to 1 / e of the maximum intensity 2 . In equation (1), the Rayleigh range Z o,eff of the effective spot size w R of a non-axially symmetric beam can be calculated as follows:

[0088]

[0089] where F D is a dimensionless divergence factor having a value of at least 10, in an embodiment at least 50, in an embodiment at least 100, in an embodiment at least 250, in particular at least 500, and in another embodiment at least 1000. In further embodiments, F D may be in the range of 10 to 2000, in particular in the range of 50 to 1500, and further in particular in the range of 100 to 1000. For non-diffracting or quasi-non-diffracting beams, the distance at which the effective spot size doubles (Rayleigh range) (Z R in equation (1)) is F D times the distance expected when using a typical Gaussian beam profile. The dimensionless divergence factor F D provides a criterion for determining whether a laser beam is quasi-non-diffracting. As used herein, a pulsed laser beam 112 is considered quasi-non-diffracting if its characteristics satisfy equation (1) at a value of F D ≥ 10. As the value of F D increases, the pulsed laser beam 112 approaches a more perfect non-diffracting state. Thus, as the value of F D increases, the length of the laser beam focal line increases, facilitating the formation of longer defects.

[0090] Additional information regarding the Rayleigh range, beam divergence, intensity distribution, axially symmetric and non-axially symmetric beams, and spot size used herein can also be found in International Standards ISO 11146-1 :2005(E) entitled "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) entitled "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) entitled "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," the disclosures of which are incorporated herein by reference in their entireties.

[0091] Referring now to Figure 1A and Figure 1B schematically depict a coated substrate 120 including a transparent workpiece 122 and a coating layer 121 disposed on the transparent workpiece 122 that is subjected to laser processing according to the methods described herein. In particular, Figure 1A and Figure 1BA schematic depiction shows a pulsed laser beam 112, output from a pulsed beam source 110 (such as a Gaussian pulsed beam source) and oriented along a beam path 111, being guided into a coated substrate 120 to form a defect 172 in the coated substrate 120, for example, the defect 172 extending into both the coating layer 121 and the transparent workpiece 122. For example, aspherical optical elements 135 and one or more lenses are used. Figure 2 A pulsed laser beam 112 propagates along a beam path 111 and is oriented such that the pulsed laser beam 112 can be focused into a pulsed laser beam focal line 113 on the coated substrate 120. The pulsed laser beam focal line 113 induces absorption within the transparent workpiece 122 and, in some embodiments, within the coating layer 121, to create a defect 172 within the coated substrate 120, which can extend to both the coating layer 121 and the transparent workpiece 122. Furthermore, by translating the pulsed laser beam 112 relative to each other and the coated substrate 120 in a translation direction 101, a contour 170 of the defect 172 can be formed in the coated substrate 120.

[0092] Also Figure 1A As shown, a pulsed laser beam 112 forms a beam spot 114 projected onto a first surface 123 of a coated substrate 120. Figure 1A In this context, the first surface 123 is the surface of the coating layer 121. The coating layer 121 may comprise any material having a transmittance greater than 70% per millimeter of material depth, including the wavelength λ of the pulsed laser beam 112. Not intended to be theoretically limited, transmittance loss is due to scattering or absorption, and minimizing transmittance loss minimizes disruption to the formation of the pulsed laser beam focal line 113 in the coating layer 121 and the transparent workpiece 122. In some embodiments, the transmittance is greater than 90% per millimeter of material depth, such as greater than 95% per millimeter of material depth. Furthermore, the material of the coating layer 121 has a uniform phase change (e.g., a phase change caused by the refractive index). Not intended to be theoretically limited, any step in the phase change would result in a loss of focus on the one-μm scale. Indeed, non-uniform changes in the phase or direction of light cause scattering, which reduces transmittance. Although the coating layer 121 may comprise any material having a transmittance greater than 70% per millimeter of material depth to the wavelength λ of the pulsed laser beam 112, example materials include metal oxides and polymers.

[0093] Also refer to Figure 2 The pulsed laser beam 112 can be focused into the pulsed laser beam focal line 113 using lens 132, which is the final focusing element in the optical assembly 100. Although in Figure 1A and Figure 1Bdepicts a single lens 132, but the optical assembly 100 further includes an aspheric optical element 135 that modifies the pulsed laser beam 112 such that the pulsed laser beam 112 has quasi-non-diffracting properties downstream of the aspheric optical element 135. Thus, when Figure 1A and Figure 1B the portion of the pulsed laser beam 112 shown in Figure 2 impinges on the lens 132, the pulsed laser beam 112 has quasi-non-diffracting properties. Moreover, some embodiments can include a lens assembly 130 that includes, for example, a first lens 131 and a second lens 132 and their repetitions (not shown) for focusing the pulsed laser beam 112 into a pulsed laser beam focal line 113.

[0094] As Figure 1A depicted, the pulsed laser beam 112 can include a ring shape when impinging on the lens 132. While in Figure 1A the lens 132 is depicted as focusing the pulsed laser beam 112 into the pulsed laser beam focal line 113, other embodiments can use an aspheric optical element 135 Figure 2 that modifies the pulsed laser beam 112 such that the pulsed laser beam 112 has quasi-non-diffracting properties downstream of the aspheric optical element 135, also for focusing the pulsed laser beam 112 into the pulsed laser beam focal line 113. In other words, in some embodiments, the lens 132 can be the final focusing element, while in other embodiments, the aspheric optical element 135 can be the final focusing element. The length of the pulsed laser beam focal line 113 can be in a range from about 0.1 mm to about 100 mm, or in a range from about 0.1 mm to about 10 mm. Various embodiments can be configured to have a pulsed laser beam focal line 113 with a length / 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, e.g., from about 0.5 mm to about 5 mm. The length of the pulsed laser beam focal line 113 can be selected based on the particular laser processing target. As one example, for a thicker coated substrate 120, it can be advantageous to form a longer pulsed laser beam focal line 113. As another example, if it is desired that the defects 172 extend only to a discrete depth portion of the coated substrate 120, it can be advantageous to form a shorter pulsed laser beam focal line 113.

[0095] Reference is now made to Figure 2The diagram schematically depicts an optical assembly 100 for generating a quasi-diffractive pulsed laser beam 112, which uses an aspherical optical element 135 (e.g., an axipyramidal 136) to form a laser beam focal line 113 at a coated substrate 120 comprising a coating layer 121 and a transparent workpiece 122. The optical assembly 100 includes a pulsed beam source 110 for outputting the pulsed laser beam 112, and a lens assembly 130 comprising a first lens 131 and a second lens 132. The coated substrate 120 can be positioned such that the pulsed laser beam 112 output from the pulsed beam source 110 irradiates the coating layer 121 and the transparent workpiece 122, for example, after passing through the aspherical optical element 135 and subsequently through both the first lens 131 and the second lens 132.

[0096] An aspherical optical element 135 is positioned within a beam path 111 between a pulsed beam source 110 and a coated substrate 120. In operation, propagating a pulsed laser beam 112 (e.g., an incident Gaussian beam) through the aspherical optical element 135 can alter (e.g., change the phase) the pulsed laser beam 112, such that the portion of the pulsed laser beam 112 propagating beyond the aspherical optical element 135 is quasi-diffractive, as described above. The aspherical optical element 135 can include any optical element comprising an aspherical shape. In some embodiments, the aspherical optical element 135 can include a conical wavefront generating optical element, such as an axial pyramid lens, for example, a negative refractive index axial pyramid lens (e.g., a negative axial pyramid), a positive refractive index axial pyramid lens, a reflection axial pyramid lens, a diffraction axial pyramid lens, a phase axial pyramid, a diffractive optics, a cubic optical element, etc.

[0097] Although optical assembly 100 is primarily described as using aspherical optical element 135 to modify the pulsed laser beam 112 into a quasi-diffractive beam, it should be understood that a quasi-diffractive beam can also be formed by other phase-changing optical elements, such as spatial light modulators, adaptive phase plates, static phase plates, deformable mirrors, diffraction gratings, etc. Each of these phase-changing optical elements (including aspherical optical element 135) modifies the phase of the pulsed laser beam 112 to reduce beam divergence, increase the Rayleigh range, and form a quasi-diffractive beam as mathematically defined above.

[0098] Still referencing Figure 2The lens assembly 130 includes two lenses, with a first lens 131 positioned upstream of a second lens 132. The first lens 131 can collimate the pulsed laser beam 112 within a collimated space 134 between the first lens 131 and the second lens 132. Further, the second lens 132 of the lens assembly 130, positioned most downstream, can focus the pulsed laser beam 112 into the transparent workpiece 122. In some embodiments, the first lens 131 and the second lens 132 each include a plano-convex lens. When the first lens 131 and the second lens 132 each include a plano-convex lens, the curvature of the first lens 131 and the second lens 132 can each be oriented toward the collimated space 134. In other embodiments, the first lens 131 can include a collimating lens, and the second lens 132 can include a meniscus lens, an aspheric lens, or another higher order corrected focusing lens. In operation, the lens assembly 130 can control the position of the pulsed laser beam focal line 113 along the beam path 111. In further embodiments, the lens assembly 130 can include an 8F lens assembly, a 4F lens assembly including a single group of the first lens 131 and the second lens 132, or any other known or yet to be developed lens assembly 130 for focusing the pulsed laser beam 112 into the pulsed laser beam focal line 113. Further, it should be understood that some embodiments can not include the lens assembly 130, and instead, an aspheric optical element 135 can focus the pulsed laser beam 112 into the laser beam focal line 113. For example, the aspheric optical element 135 can convert the pulsed laser beam 112 into a quasi-non-diffracting laser beam and focus the quasi-non-diffracting laser beam onto the pulsed laser beam focal line 113.

[0099] Reference is made to Figures 1A-2 The pulsed beam source 110 is configured to output a pulsed laser beam 112. In operation, the defect 172 of the profile 170 is created by the interaction of the transparent workpiece 122 with the pulsed laser beam 112 output by the pulsed beam source 110, modified by the aspheric optical element 135 and / or the lens assembly 130. In operation, the pulsed laser beam 112 output by the laser beam source 110 can create multiphoton absorption (MPA) in the transparent workpiece 122. MPA is the simultaneous absorption of two or more photons of the same or different frequencies that excites a molecule from one state, typically the ground state, to a higher energy electronic state (i.e., ionization). The energy difference between the lower state and the higher state of the molecule involved is equal to the sum of the energies of the photons involved. MPA (also known as induced absorption) can be a second or third (or higher) order process that is, for example, several orders of magnitude weaker than linear absorption. It differs from linear absorption in that, for example, the intensity of the second order induced absorption can be proportional to the square of the light intensity, and thus it is a nonlinear optical process.

[0100] In some embodiments, the pulsed laser source 110 may output a pulsed laser beam 112 including wavelengths such as 1064 nm, 1030 nm, 532 nm, 530 nm, 355 nm, 343 nm, 266 nm, or 215 nm. Furthermore, the pulsed laser beam 112 used to form defects 172 in the transparent workpiece 122 is well-suited for materials transparent to the selected pulsed laser wavelength. A suitable laser wavelength for forming defects 172 refers to a wavelength at which the combined loss of linear absorption and scattering of the transparent workpiece 122 is sufficiently low. In embodiments, the combined loss caused by linear absorption and scattering of the transparent workpiece 122 and the coating layer 121 at the laser wavelength 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, such as 0.5% / mm to 20% / mm, 1% / mm to 10% / mm, or 1% / mm to 5% / mm, for example, 1% / mm, 2.5% / mm, 5% / mm, 10% / mm, 15% / mm, or any range having any two of these values ​​as endpoints, or any open range having any one of these values ​​as a lower limit. As used herein, dimension “ / mm” refers to the distance per millimeter within the transparent workpiece 122 in the beam propagation direction (i.e., the Z direction) of the pulsed laser beam 112. Representative laser wavelengths for many glass workpieces include Nd... 3+ The fundamental and harmonic wavelengths (e.g., Nd234 nm with a fundamental wavelength close to 1064 nm and higher-order harmonic wavelengths close to 532 nm, 355 nm and 266 nm) 3+ :YAG or Nd 3+ (YVO4). Other laser wavelengths in the ultraviolet, visible, and infrared portions of the spectrum that meet the linear absorption and scattering loss requirements of a given combination of substrate materials can also be used.

[0101] Still referencing Figures 1A-2 In operation, the contour 170 can be formed on the coated substrate 120 by irradiating the contour line 142 with a pulsed laser beam 112 and translating at least one of the pulsed laser beam 112 and the coated substrate 120 relative to each other in the translation direction 101 along the contour line 142 to form a defect 172 of the contour 170. Although Figure 1AThe depicted contour 170 is linear, but it should be appreciated that the contour 170 can be non-linear, e.g., curved. Moreover, in some embodiments, the contour 170 can be a closed contour, such as a circle, a rectangle, an ellipse, a square, a hexagon, an oval, a regular geometric shape, an irregular shape, a polygon, an arbitrary shape, etc. The contour line 142 represents a boundary between a main area 124 of the coated substrate 120 and a dummy area 126. The main area 124 is an area of the coated substrate 120 to be used as a resulting product, while the dummy area 126 is a scrap area.

[0102] The pulsed laser beam 112 is directed or positioned into the coated substrate 120 to induce absorption (e.g., MPA) within the coating layer 121, the transparent workpiece 122, or both (depending on whether the pulsed laser beam focal line 113 extends into the coating layer 121, the transparent workpiece 122, or both), depositing sufficient energy to break chemical bonds in the coating layer 121 and / or the transparent workpiece 122 at spaced locations along the contour line 142, thereby forming a defect 172. According to one or more embodiments, the pulsed laser beam 112 can be translated across the coated substrate 120 by motion of the coated substrate 120 (e.g., motion of a translation stage 190 coupled to the coated substrate 120), motion of the pulsed laser beam 112 (e.g., motion of the pulsed laser beam focal line 113), or motion of both the coated substrate 120 and the pulsed laser beam focal line 113. By translating at least one of the pulsed laser beam focal line 113 relative to the coated substrate 120, a plurality of defects 172 can be formed in the coated substrate 120.

[0103] In some embodiments, the defects 172 can generally be spaced apart from each other along the profile 170 by a distance of 0.1 pm to 500 pm, such as 1 pm to 200 pm, 2 pm to 100 pm, or 5 pm to 20 pm, 0.1 pm to 50 pm, 5 pm to 15 pm, 5 pm to 12 pm, 7 pm to 15 pm, 8 pm to 15 pm, or 8 pm to 12 pm, such as 50 pm or less, 45 pm or less, 40 pm or less, 35 pm or less, 30 pm or less, 25 pm or less, 20 pm or less, 15 pm or less, 10 pm or less, such as 100 pm, 75 pm, 50 pm, 40 pm, 30 pm, 25 pm, 10 pm, 5 pm, or any range having an end point of any two of these values, or any open range having a lower limit of any of these values. While not wishing to be bound by theory, increasing the spacing distance between adjacent defects 172 can increase the processing speed (i.e., decrease the processing time), and decreasing the spacing distance between adjacent defects 172 can decrease the fracture resistance of the profile 170 of defects 172. Further, translation of the coated substrate 120 relative to the pulsed laser beam 112 can be performed by moving the coated substrate 120 and / or the pulsed beam source 110 using one or more translation stages 190.

[0104] Referring now to Figures 1A-3 The force required to separate the coated substrate 120 along the profile 170 (i.e., the fracture resistance) is reduced when the defects 172 of one or more profiles 170 are formed by a pulse train 50 having at least two sub-pulses 51, as compared to the fracture resistance of the same profile 170 of the same shape having the same spacing between adjacent defects 172 in the same coated substrate 120 formed using a single pulsed laser having the same energy as the combined energy of the sub-pulses of the pulse train 50. A pulse train, such as the pulse train 50, is a short and fast group of sub-pulses (i.e., a compact cluster of sub-pulses, such as the sub-pulses 51) emitted by a laser and interacting with a material (i.e., the MPA in the material of the coating layer 121 and / or the transparent workpiece 122). The use of the pulse train 50 (as opposed to single pulse operation) increases the size (e.g., cross-sectional size) of the defects 172, which facilitates the joining of adjacent defects 172 when separating the coated substrate 120 along the profile 170, thereby minimizing the formation of cracks in the separated portions of the coated substrate 120 away from the profile 170.

[0105] Still referring to Figures 1A-3In some embodiments, the pulses generated by the pulsed beam source 110 are generated in pulse bursts 50, each pulse burst 50 having two sub-pulses 51 or more sub-pulses, such as 2 to 30 sub-pulses 51 per pulse burst 50, or 5 to 20 sub-pulses 51 per pulse burst 50. Further, the energy required to modify the coating layer 121 and / or the transparent workpiece 122 is the pulse energy, which can be described in terms of pulse burst energy (i.e., the energy contained in a pulse burst 50, where each pulse burst 50 contains a series of sub-pulses 51; that is, the pulse burst energy is the combined energy of all the sub-pulses within the pulse burst). The pulse energy (e.g., pulse burst energy) can be 25 pJ to 1000 pJ or 25 pJ to 750 pJ, such as 100 pJ to 600 pJ, 50 pJ to 500 pJ, or 50 pJ to 250 pJ, for example, 25 pJ, 50 pJ, 75 pJ, 100 pJ, 200 pJ, 250 pJ, 300 pJ, 400 pJ, 500 pJ, 600 pJ, 750 pJ, or any range having any two of these values as endpoints, or any open range having any of these values as a lower limit.

[0106] Reference is now made to Figures 4-5B In use, for example, according to the embodiment of FIG. 1- Figure 3 After the profile 170 of defects 172 is formed in the coated substrate 120 along the profile line 142 in one of the embodiments according to FIG. 1-3, the coated substrate 120 can be further acted upon in a subsequent separation step to induce separation of the transparent workpiece 122 and the coating layer 121 along the profile line 142 (i.e., along the profile 170 of defects 172). The subsequent separation step includes directing an infrared laser beam 212 onto the coated substrate 120 to apply a thermal stress to the coating layer 121 and the transparent workpiece 122. The applied thermal stress induces separation in the coated substrate 120 extending along the profile line 142 between adjacent defects 172. In the transparent workpiece 122, such separation can include propagation of a crack along the profile line 142.

[0107] Without being bound by theory, the infrared laser beam 212 acts as a controlled heat source, rapidly increasing the temperature of the coating layer 121 at or near the contour line 142, modifying the material of the coating layer 121 along or near the contour line 142 to induce separation of the material of the coating layer 121 extending between adjacent defects 172. Furthermore, this rapid heating can create compressive stress in or near the contour line 170 of the transparent workpiece 122. Since the heated surface area of ​​the transparent workpiece 122 is relatively small and shallow compared to its entire surface area, the heated region cools relatively quickly. The resulting temperature gradient induces tensile stress in the transparent workpiece 122 sufficient to propagate a crack along the contour line 170 and through the depth of the transparent workpiece 122, thereby causing complete separation of the transparent workpiece 122 along the contour line 170. Without being bound by theory, it is believed that the tensile stress can be caused by the expansion (i.e., changing density) of the glass in the portion of the workpiece having a higher local temperature induced by the infrared laser beam 212. Infrared laser beam 212 induces separation of the coating layer 121 and the transparent workpiece 122 along the contour line 142 via the coated substrate 120.

[0108] Figure 4 An optical assembly 200 is depicted, comprising an infrared beam source 210 configured to generate an infrared laser beam 212. The infrared beam source 210 may include a carbon dioxide laser (“CO2 laser”), a carbon monoxide laser (“CO laser”), a solid-state laser, a laser diode, or a combination thereof. The infrared laser beam 212 includes wavelengths readily absorbed by the transparent workpiece 122, for example, wavelengths in the range of 1.2 μm to 13 μm, such as the range of 4 μm to 12 μm. The power of the infrared laser beam 212 may be from about 10 W to about 4000 W, such as 100 W, 250 W, 500 W, 750 W, 1000 W, etc. Furthermore, the infrared beam source 210 may include a continuous-wave laser or a pulsed laser. The optical assembly 200 further includes a lens assembly 230 comprising a lens 232 for focusing the infrared laser beam 212 onto a coated substrate 120. In operation, the infrared laser beam 212 propagates along the infrared beam path 211 and is oriented such that the infrared laser beam can be guided onto the coated substrate 120, for example, by focusing it onto the first surface 123 of the coated substrate 120 using a lens 232.

[0109] Now for reference Figure 5A The image schematically depicts a cross-section of a coated substrate 120 with a contour 170 of defect 172 during laser processing using an infrared laser beam 212. Figure 5A In China, use Figure 4The optical component 200, with an infrared laser beam 212 guided onto the coated substrate 120, includes a Gaussian intensity profile on the coated substrate 120. Furthermore, in Figure 5A In this process, an infrared laser beam 212 is guided onto a coated substrate 120 aligned with the contour 170 of the defect 172 and thus with the contour line 142. Because the infrared laser beam 212 comprises a Gaussian energy distribution, the interaction between the infrared laser beam 212 and the coated substrate 120 forms a heat-affected region 140 with a Gaussian shape. The heat-affected region 140 corresponds to a portion of the coated substrate 120 that receives sufficient energy from the Gaussian energy distribution of the infrared laser beam 212 to generate thermal stress sufficient to induce separation of the coated substrate 120 along the contour 170. That is, the heat-affected region 140 includes portions of the coating layer 121 and portions of the transparent workpiece 122, to which sufficient thermal energy to induce separation of the contour 170 of the defect 172 is applied. However, as... Figure 5A As shown, when the infrared laser beam 212 is guided onto the coated substrate 120 aligned with the contour 170 of the defect 172, heat-affected regions 140 are symmetrically formed in the dummy region 126 and the main region 124. This causes some melting and ablation, for example, by melting or ablating the coating layer 121 on the main region 124, damaging the main region 124. In fact, Figure 5B It shows Figure 5A A top view of the coated substrate 120, wherein the coating is used Figure 5A The laser processing technology shown separates a series of defects 172. For example... Figure 5B As shown, the heat-affected zone 140 extends into the main zone 124, illustrating the use of Figure 5A The technique caused undesirable damage within the main region 124. As described above, the main region 124 is the area to be used as the coated substrate 120 of the resulting product, therefore any damage to the main region 124 is undesirable. Conversely, the dummy region 126 is a waste region.

[0110] Now for reference Figure 6 One potential solution to prevent damage to the main region 124 is to deflect the infrared laser beam 212 away from the defect 172 and primarily guide the infrared laser beam 212 onto a dummy region 126 on the coated substrate 120, which is offset from the contour 170 of the defect 172 and away from the main region 124. Figure 6 In China, use Figure 4of the optical assembly 200, the infrared laser beam 212 is directed onto the coated substrate 120 and includes a Gaussian intensity profile at the coated substrate 120. Directing the infrared laser beam 212 onto the dummy region 126 away from the primary region 124 modifies the coating layer 121 on the dummy region 126 adjacent and along the profile 170 of the defect 172 without ablating, melting, coloring, surface altering, and / or altering the electrical conductivity of the coating layer 121 on the primary region 124. That is, placing the infrared laser beam 212 into the dummy region 126 away from the profile 170 reduces the thermal energy of the Gaussian energy distribution of the infrared laser beam from the portion of the coating layer 121 that is transferred into the primary region 124 to a degree sufficient to avoid damage. However, because the infrared laser beam 212 includes a Gaussian intensity profile at the coated substrate 120, positioning the infrared laser beam 212 far enough away from the profile 170 of the defect 172 to prevent damage to the primary region 124 can not induce separation of the material of the coated substrate 120 between adjacent defects 172 because it reduces the resulting temperature gradient near the defect 172. For example, positioning the infrared laser beam 212 far enough away from the profile 170 of the defect 172 to prevent damage to the primary region 124 can not induce a tensile stress in the transparent workpiece 122 sufficient to propagate a crack along the profile 170 and through the depth of the transparent workpiece 122 because it reduces the resulting temperature gradient near the defect 172. Thus, alternative techniques for separating the coated substrate 120 (i.e., separating the primary region 124 from the dummy region 126) while minimizing or preventing damage to the primary region 124 are desired.

[0111] Still referring to FIG. 1, Figure 6 One technique to separate the coated substrate 120 while minimizing damage to the primary region 124 is to translate the infrared laser beam 212 away from the profile line 142 along a plurality of channels, where each individual channel does not impart enough thermal energy to damage the primary region 124. While a single channel can not be sufficient to separate the profile 170 of the defect 172 (particularly the portion of the profile 170 of the defect 172 that extends into the transparent workpiece 122), the thermal energy accumulates in the transparent workpiece 122 based on the plurality of channels, thereby inducing the coated substrate 120 to separate along the profile 170 of the defect 172 without damaging the primary region 124. Further, each channel can follow the same path or offset paths, each path positioned along the dummy region 126.

[0112] Referring now to FIG. 2, Figures 7A-9B Additional techniques for generating thermal stresses sufficient to induce a series of defects 172 of the coated substrate 120 to separate along the profile line 142 while limiting or preventing damage to the primary region 124 of the coated substrate 120 will now be described. In particular, Figures 7A-7DMethods of laser processing a coated substrate 120 using an infrared laser beam 212 with a Gaussian intensity profile are depicted, Figure 4 Methods of laser processing a coated substrate 120 using an infrared laser beam 212 with a modified energy distribution are depicted, and Figures 8A-8C Methods of laser processing a coated substrate 120 using an infrared laser beam 212 with a modified energy distribution are depicted, and Figure 9A and Figure 9B Methods of laser processing a coated substrate 120 using an infrared laser beam 212” that is shaped into a ring and directed onto a first surface 123 of the coated substrate 120 off the focal plane 204 of the final focusing element are depicted. Each of these techniques induces separation of the profile 170 of the defects 172 in the coated substrate 120 in a single pass, while limiting or preventing damage to the main area 124 of the coated substrate 120. In fact, the techniques described herein reduce contact time, reduce debris generated during processing, and reduce the complexity of the optical system. Furthermore, while the techniques are described herein primarily with respect to a coated substrate 120 that includes a transparent workpiece 122 and a coating layer 121, it should be understood that the techniques are also applicable to separation of a single substrate, such as a transparent workpiece that is uncoated, which can benefit from a reduction in chipping and thermal cracking, and thus a higher release rate.

[0113] Reference is now made to Figures 7A-7C , depicting a schematic top view of a coated substrate 120 including a plurality of defects 172 positioned along a profile line 142 that undergo a separation step using an infrared laser beam 212. In Figures 7A-7C Methods in which the infrared laser beam 212 follows an oscillating path 150 are depicted. Specifically, at least one of the coated substrate 120 and the infrared laser beam 212 is translated relative to the other such that the infrared beam spot 214 traces the oscillating path 150. The infrared beam spot 214 is projected on the first surface 123 of the coated substrate 120 by the infrared laser beam 212. The oscillating path 150 is disposed on the dummy area 126 such that the infrared laser beam 212 causes minimal or no damage to the dummy area 124. Similar to the above Figure 6In this embodiment, the infrared laser beam 212 comprises a Gaussian energy distribution; however, the oscillation path 150 helps to apply sufficient thermal energy to the dummy region 126 of the coated substrate 120 to induce separation of the coated substrate 120 along the contour line 142, while avoiding damage to the main region 124. The traversal of the infrared laser beam 212 along the oscillation path 150 provides a mechanism for controlling the amount of thermal energy transferred to the main region 124. As the infrared laser beam 212 moves closer to the contour line 142, more thermal energy is transferred to the vicinity of the defect 172 and sufficient thermal energy can be obtained to induce separation of the transparent workpiece 122. To prevent damage to the coating layer 121 in the main region 124, the movement of the infrared laser beam 212 is reversed and moved away from the contour line 142 to prevent excessive thermal energy transfer to the main region 124. By controlling the power of the infrared laser beam 212, the crossing speed of the infrared laser beam 212 along the oscillation path 150, the proximity of the infrared laser beam 212 to the contour line 142, and the number of times the infrared laser beam 212 reaches the distance to the closest contour line 142, the transfer of heat energy is controlled, and the separation of the main region 124 and the dummy region 126 can be achieved without damaging the coating layer 121 in the main region 124.

[0114] like Figures 7A-7C As depicted, the oscillation path 150 follows the offset line 144 in the translational direction, while oscillating between the inner orbital line 146 and the outer orbital line 148. Figures 7A-7C In the depicted embodiments, each oscillation extends from one of the inner track line 146 or the outer track line 148 to the other. However, it should be understood that in some embodiments, the oscillation path 150 may oscillate between the inner track line 146 and the outer track line 148, and during some or all of these oscillations, it may not reach the inner track line 146, the outer track line 148, or both. Each of the offset line 144, the inner track line 146, and the outer track line 148 is disposed on the dummy region 126 of the coated substrate 120. Specifically, each of the offset line 144, the inner track line 146, and the outer track line 148 is a parallel path on the dummy region 126 of the coated substrate 120, and each is parallel to the contour line 142. For example, in Figure 7A In the embodiment depicted, the contour line 142 is linear along the Y-axis and the horizontal axis is the X-axis. However, it should be understood that the contour line 142 and the offset line 144 may be curved or otherwise non-linear, and therefore the horizontal axis may change at points along the offset line 144 to maintain orthogonality to the offset line 144.

[0115] The offset line 144 can be spaced 0.2 mm to 3 mm from the contour line 142, such as 0.5 mm to 2 mm from the contour line 142, for example, the offset line 144 can be spaced the following distances from the contour line 142: 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2 mm, 2.25 mm, 2.5 mm, 2.75 mm, 3 mm, or any range having any two of these values as end points. The inner track line 146 can be spaced 0.25 mm to 2 mm from the contour line 142, such as 0.5 mm to 1.5 mm from the contour line 142, for example, the inner track line 146 can be spaced the following distances from the contour line 142: 0.25 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.75 mm, 2 mm, or any range having any two of these values as end points. The outer track line 148 can be spaced 0.75 mm to 4 mm from the contour line 142, such as 1.5 mm to 2.5 mm from the contour line 142, for example, the outer track line 148 can be spaced the following distances from the contour line 142: 0.75 mm, 1 mm, 1.25 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm, 2.75 mm, 3 mm, 3.25 mm, 3.5 mm, 3.75 mm, 4 mm, or any range having any two of these values as end points. Further, the offset line 144 can be equally spaced from both the inner track line 146 and the outer track line 148. Further, the spacing distance between the offset line 144 and each of the inner track line 146 and the outer track line 148 can be the same as the distance between the inner track line 146 and the contour line 142.

[0116] Further, the spacing distances between the contour line 142, the offset line 144, the inner track line 146, and the outer track line 148 can be a function of the 1 / e 2 beam diameter of the infrared beam spot 214. For example, the spacing distances between the contour line 142, the offset line 144, the inner track line 146, and the outer track line 148 can be at least half of the 1 / e 2 beam diameter of the infrared beam spot 214. The 1 / e 2The beam diameter is in the range of 350 pm to 2 mm, such as 500 pm to 1 mm, or 600 pm to 900 pm, for example, 500 pm, 550 pm, 600 pm, 650 pm, 700 pm, 750 pm, 800 pm, 850 pm, 900 pm, 950 pm, 1 mm, 1.5 mm, 2 mm, or any range having any two of these values as endpoints. In operation, the 1 / e2area of the infrared beam spot 214 in the above ranges is 2 The beam diameter can facilitate high precision application of thermal energy to the coated substrate 120 and allow the infrared beam spot 214 to oscillate along the oscillating path 150 without impinging on the primary area 124.

[0117] In operation, as the infrared laser beam 212 is translated such that the infrared beam spot 214 tracks the oscillating path 150, the infrared laser beam 212 applies thermal energy to the coated substrate 120 to induce separation of the series of defects 172 of the coated substrate 120 along the contour line 142 while limiting or preventing damage to the primary area 124 of the coated substrate 120. For example, as depicted in FIG. 1A, the infrared laser beam 212 applies thermal energy to the coated substrate 120 to induce separation of the series of defects 172 of the coated substrate 120 along the contour line 142 while limiting or preventing damage to the primary area 124 of the coated substrate 120. Figure 4 The scanner 192 is coupled to the infrared beam source 210 and is configured to translate the infrared beam source 210 and the infrared laser beam 212 such that the infrared beam spot 214 tracks the oscillating path 150. In particular, the scanner 192 can oscillate the infrared laser beam 212 while linearly translating the infrared laser beam 212. The speed of motion of the infrared laser beam 212 is preferably greater than or equal to 10 mm / s, such as between 10 mm / s and 2000 mm / s, or between 20 mm / s and 1500 mm / s, or between 30 mm / s and 1200 mm / s, or between 40 mm / s and 1000 mm / s, or between 50 mm / s and 800 mm / s, or between 60 mm / s and 500 mm / s.

[0118] Furthermore, Figures 7A-7C Each of FIGS. 1A-1C depict different embodiments of the oscillating path 150. For example, Figure 7A FIG. 1A depicts an embodiment in which the oscillating path 150 is a pendulum path 155, Figure 7B FIG. 1B depicts an embodiment in which the oscillating path 150 is a swing path 153, and Figure 7C FIG. 1C depicts an embodiment in which the oscillating path 150 is a sawtooth path 154.

[0119] Reference is now made to Figure 7AIn some embodiments, the oscillation path 150 is a pendulum path 155 that follows an offset line 144 in the translational direction while oscillating along a horizontal axis between an inner track line 146 and an outer track line 148, wherein the horizontal axis is orthogonal to the offset line 144. For example, the pendulum path 155 has a plurality of circular portions 151 and a plurality of straight portions 152. The plurality of circular portions 151 each reach either the inner track line 146 or the outer track line 148. Furthermore, the straight portions 152 each extend between two circular portions 151 and cross the offset line 144. In practice, as Figure 7A As shown, the straight portion 152 extends along a horizontal axis orthogonal to the offset line 144. In some embodiments, each of the plurality of straight portions 152 includes a length of 0.25 mm to 2 mm, such as 0.5 mm to 1.5 mm, for example, 0.25 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.75 mm, 2 mm, or any range having any two of these values ​​as endpoints. In some embodiments, each of the plurality of circular portions 151 includes a radius of curvature of 0.25 mm to 2 mm, such as 0.5 mm to 1.5 mm, for example, 0.25 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.75 mm, 2 mm, or any range having any two of these values ​​as endpoints.

[0120] Now for reference Figure 7B In some embodiments, the oscillation path 150 is a swing path 153 that oscillates and rotates between the inner track line 146 and the outer track line 148 while following the offset line 144 in the translational direction. In operation, the swing path 153 can be implemented using a scanner 192. Specifically, the scanner 192 can rotate an infrared laser beam 212 (e.g., rotate an infrared beam source 210) in a circular pattern about its central axis while linearly translating the infrared laser beam 210 in the translational direction to follow the offset line 144. In some embodiments, the circular pattern is circular or elliptical, and in some embodiments, the circular pattern can be a lisajou pattern. Reference now. Figure 7C In some embodiments, the oscillation path 150 is a sawtooth path 154, which has multiple straight partial connections at or between the inner track line 146 and the outer track line 148, while following the offset line 144 in the translation direction.

[0121] Now for reference Figures 7A-7D , by alongFigures 7A-7C oscillating path 150 irradiates the dummy region 126 of the coated substrate 120 with the infrared laser beam 212, the cumulative fluence applied to the dummy region 126 of the coated substrate 120 by the infrared laser beam 212 follows a top-hat cumulative fluence distribution in which 20% or less of the total energy applied to the dummy region 126 is applied to portions of the dummy region 126 that are not located between the inner orbit line 146 and the outer orbit line 148, and portions of the dummy region 126 that are located between the inner orbit line 146 and the outer orbit line 148 are impinged with a cumulative fluence that is greater than 80% of the maximum cumulative fluence applied to any portion of the dummy region 126. In Figure 7D this top-hat cumulative fluence distribution is graphically depicted in

[0122] Reference is now made to Figures 8A-8C , which schematically illustrates another method of laser processing a coated substrate 120 using an infrared laser beam 212’ having a modified energy distribution. FIG. 8 schematically illustrates an optical assembly 200’ and a lens assembly 230’ that includes Figure 4 the optical assembly 200 of FIG. 1, with the addition of a diffractive optical element 238 for modifying the intensity profile of the infrared laser beam 212. In particular, the infrared laser beam 212 output by the infrared beam source 210 includes a Gaussian energy distribution, and after traversing the diffractive optical element 238 and reaching the coated substrate 120, the infrared laser beam 212 (now infrared laser beam 212’) includes a modified top-hat energy distribution. Thus, the infrared beam spot 214’ (FIG. 8) projected onto the first surface 123 of the coated substrate 120 by the infrared laser beam 212’ includes a top-hat energy distribution. Figure 8B As used herein, a “top-hat energy distribution” refers to an energy distribution in which 20% of the total energy of an infrared beam spot (e.g., the infrared beam spot 214’ of FIG. 8) has a fluence that is less than 80% of the maximum fluence. In Figure 8B In the illustrative example of FIG. 8, 80% or more of the total energy of the infrared beam spot 214’ is within an inner region (e.g., the inner region 215) that is bounded by 80% of the maximum fluence of the infrared beam spot 214’. Figure 8B

[0123] Reference is now made to Figure 8B associated with a graph 60, schematically illustrates the use of Figure 8A ​The optical component 200' forms an infrared beam spot 214'. Graph 60 includes line 62, which shows the relative fluence as a function of relative radial position within the infrared beam spot 214'. The relative fluence at the peak of the fluence distribution is normalized to 1, and the balance of the fluence distribution is scaled proportionally. Figure 8B As shown, the infrared beam spot 214' includes an outer perimeter 218, an inner perimeter 216, and an internal region 215 defined by the inner perimeter 216, the internal region 215 being defined by a specific relative flux, such as 80% of the maximum flux of the infrared beam spot 214'. In some embodiments, the infrared beam spot 214' includes an energy distribution in which 10% or less of the total energy of the infrared beam spot 214' has a flux of less than 80% of the maximum flux. In some embodiments, the infrared beam spot 214' includes an energy distribution in which less than 5% of the total energy of the infrared beam spot 214' has a flux of less than 80% of the maximum flux. In some embodiments, the infrared beam spot 214' includes an energy distribution in which less than 5% of the total energy of the infrared beam spot 214' has a flux of less than 90% of the maximum flux.

[0124] Now for reference Figure 8C It schematically depicts the use of Figure 8A The infrared laser beam 212' is used to laser process the cross-section of the coated substrate 120. Because the infrared beam spot 214' includes a top-cap energy distribution, the resulting heat-affected region 140 formed in the coated substrate 120 has a substantially linear shape. This substantially linear shape means that the reduction in flux from 80% of the maximum flux to 10%, 5%, or even 1% of the maximum flux is steep, resulting in a significantly reduced overlap between the distribution wings and the main region 124 relative to a Gaussian distribution centered at the same location. Therefore, the high-flux region of the top-cap energy distribution can be placed closer to the defect 172 to facilitate thermal separation without damaging the coating 121 in the main region 124. In operation, the infrared laser beam 212' projects the infrared beam spot 214' onto the first surface 123 of the coated substrate 120 in the dummy region 126 of the coated substrate 120. Specifically, the infrared beam spot 214' is projected onto the offset line 144, causing the infrared beam spot 214' to deviate from the contour line 142. For example, the infrared beam spot 214' can be centered on the offset line 144, such that the offset line 144 bisects the infrared beam spot 214'. In some embodiments, the inner periphery 216 of the infrared beam spot 214' can be located at the inner track line 146 and the outer track line 148, or located between the inner track line 146 and the outer track line 148.

[0125] use Figures 8A-8Cfurther includes translating at least one of the coated substrate 120 and the infrared laser beam 212’ relative to one another such that the infrared beam spot 214’ follows the offset line 144. Without intending to be limited by theory, the infrared laser beam 212’ applies thermal energy to the coated substrate 120 to induce separation of the series of defects 172 of the coated substrate 120 along the contour line 142 while limiting or preventing damage to the primary area 124 of the coated substrate 120. Indeed, because the infrared beam spot 214’ includes a modified energy profile (e.g., a top hat energy profile) that sharply drops off at a particular radial position, the infrared laser beam 212’ will apply sufficient thermal energy to the dummy area 126 rather than the primary area 124 of the coated substrate 120 to damage the coated substrate 120. Moreover, it should be appreciated that in some embodiments, the infrared beam spot 214’ having a top hat energy profile can traverse the oscillating path 150 along Figures 7A-7C the contour line 142. Figures 8A-8C of the infrared beam spot 214’.

[0126] Reference is now made to Figure 9A schematically depicts an optical assembly 200” for laser processing using an annular infrared laser beam 212” formed using an aspheric optical element 235, such as an axicon 236. The aspheric optical element 235 can include any of the embodiments of the aspheric optical element 135 described above with reference to FIG. 1- Figure 3 Indeed, the aspheric optical element 235 can modify the infrared laser beam 212 output by the infrared beam source 210 into a phase-modified infrared laser beam 212” having an annular shape. Without intending to be limited by theory, the infrared laser beam 212” includes phase characteristics that form the pulsed laser beam 112 of FIG. 1- Figure 3 into a quasi-non-diffracting beam. However, in the embodiment depicted in Figure 9A the infrared laser beam 212” impinges the coated substrate 120 while having an annular shape (e.g., upstream of the focal plane of the final focusing element).

[0127] Moreover, as shown in Figure 9A the optical assembly 200” includes a lens assembly 230” that can further include one or more lenses 231, 232 that can include the same lenses as the lenses 131, 132 of the lens assembly 130 of FIG. 1- Figure 2 Moreover, in Figure 9AIn the embodiment of optical assembly 200” depicted in FIG. 2B, lens 232 acts as the final focusing element, i.e., the final focusing element through which infrared laser beam 212” travels before impinging on coated substrate 120. While lens 232 is depicted as the final focusing element, it should be understood that aspheric optical element 235 can alternatively be positioned as the final focusing element. The final focusing element includes a focal length extending from the final focusing element to focal plane 204. As used herein, the focal length of the final focusing element is the distance between the final focusing element and the focal plane. In the embodiment of optical assembly 200” depicted in FIG. 2B, the focal length of the final focusing element is the distance between second lens 232 and focal plane 204. Figure 9A As shown in FIG. 2B, the final focusing element (i.e., second lens 232) and the first surface 123 of the coated substrate are positioned relative to one another such that the offset of focal plane 204 from the first surface 123 of coated substrate 120 can be an offset length O L .

[0128] Referring now to FIG. 2C, a top view of coated substrate 120 is schematically depicted during laser processing using infrared laser beam 212”. In operation, laser processing of coated substrate 120 using infrared laser beam 212” includes translating at least one of coated substrate 120 and infrared laser beam 212” relative to one another such that infrared beam spot 214” follows offset line 144. For example, offset line 144 can bisect infrared beam spot 214”. Further, infrared beam spot 214” can be projected onto dummy region 126 without impinging on primary region 124. Figure 9B Referring now to FIG. 2D, a focal spread 217 of infrared laser beam 212” downstream of the final focusing element (i.e., second lens 232). As used herein, “focal spread” refers to the envelope of light of a laser beam that is refracted by an optical component and thereafter directed onto and / or into a substrate. For example, the focal spread can include the envelope of light of a laser beam extending from a most downstream optical component of an optical system onto and / or into a substrate. As shown by its focal spread 217, annularly shaped infrared laser beam 212” impinges coated substrate 120 at or between inner orbital line 146 and outer orbital line 148. Indeed, in some embodiments, offset line 144 bisects focal spread 217 of infrared laser beam 212”. Further, it should be understood that in some embodiments, infrared laser beam 212” having an annular shape can traverse oscillation path 150 along with Figures 7A-7C Referring now to FIG. 2E, a top view of coated substrate 120 is schematically depicted during laser processing using infrared laser beam 212”. In operation, laser processing of coated substrate 120 using infrared laser beam 212” includes translating at least one of coated substrate 120 and infrared laser beam 212” relative to one another such that infrared beam spot 214” follows offset line 144. For example, offset line 144 can bisect infrared beam spot 214”. Further, infrared beam spot 214” can be projected onto dummy region 126 without impinging on primary region 124. Figure 9A Referring now to FIG. 2F, a top view of coated substrate 120 is schematically depicted during laser processing using infrared laser beam 212”. In operation, laser processing of coated substrate 120 using infrared laser beam 212” includes translating at least one of coated substrate 120 and infrared laser beam 212” relative to one another such that infrared beam spot 214” follows offset line 144. For example, offset line 144 can bisect infrared beam spot 214”. Further, infrared beam spot 214” can be projected onto dummy region 126 without impinging on primary region 124. Figure 9B Referring now to FIG. 2G, a top view of coated substrate 120 is schematically depicted during laser processing using infrared laser beam 212”. In operation, laser processing of coated substrate 120 using infrared laser beam 212” includes translating at least one of coated substrate 120 and infrared laser beam 212” relative to one another such that infrared beam spot 214” follows offset line 144. For example, offset line 144 can bisect infrared beam spot 214”. Further, infrared beam spot 214” can be projected onto dummy region 126 without impinging on primary region 124.

[0129] Referring now to FIG. 2H, a top view of coated substrate 120 is schematically depicted during laser processing using infrared laser beam 212”. In operation, laser processing of coated substrate 120 using infrared laser beam 212” includes translating at least one of coated substrate 120 and infrared laser beam 212” relative to one another such that infrared beam spot 214” follows offset line 144. For example, offset line 144 can bisect infrared beam spot 214”. Further, infrared beam spot 214” can be projected onto dummy region 126 without impinging on primary region 124. Figure 9C Referring now to FIG. 2I, a top view of coated substrate 120 is schematically depicted during laser processing using infrared laser beam 212”. In operation, laser processing of coated substrate 120 using infrared laser beam 212” includes translating at least one of coated substrate 120 and infrared laser beam 212” relative to one another such that infrared beam spot 214” follows offset line 144. For example, offset line 144 can bisect infrared beam spot 214”. Further, infrared beam spot 214” can be projected onto dummy region 126 without impinging on primary region 124. Figure 9C Referring now to FIG. 2J, a top view of coated substrate 120 is schematically depicted during laser processing using infrared laser beam 212”. In operation, laser processing of coated substrate 120 using infrared laser beam 212” includes translating at least one of coated substrate 120 and infrared laser beam 212” relative to one another such that infrared beam spot 214” follows offset line 144. For example, offset line 144 can bisect infrared beam spot 214”. Further, infrared beam spot 214” can be projected onto dummy region 126 without impinging on primary region 124. Figure 9A Referring now to FIG. 2K, a top view of coated substrate 120 is schematically depicted during laser processing using infrared laser beam 212”. In operation, laser processing of coated substrate 120 using infrared laser beam 212” includes translating at least one of coated substrate 120 and infrared laser beam 212” relative to one another such that infrared beam spot 214” follows offset line 144. For example, offset line 144 can bisect infrared beam spot 214”. Further, infrared beam spot 214” can be projected onto dummy region 126 without impinging on primary region 124. Figure 9A Referring now to FIG. 2L, a top view of coated substrate 120 is schematically depicted during laser processing using infrared laser beam 212”. In operation, laser processing of coated substrate 120 using infrared laser beam 212” includes translating at least one of coated substrate 120 and infrared laser beam 212” relative to one another such that infrared beam spot 214” follows offset line 144. For example, offset line 144 can bisect infrared beam spot 214”. Further, infrared beam spot 214” can be projected onto dummy region 126 without impinging on primary region 124.

[0130] Further, in some embodiments, the infrared laser beam 212” comprises a pulsed infrared laser beam (i.e., in some embodiments, the infrared beam source 210 can be a pulsed infrared beam source). In embodiments in which the infrared laser beam 212” is a pulsed infrared laser beam, as at least one of the coated substrate 120 and the infrared laser beam 212” is translated relative to the other, the infrared laser beam 212” impinges the first surface of the coated substrate at locations along the offset line (i.e., impingement locations 141) that are spaced from one another by a distance of ¼ to ½ the infrared beam spot 214” diameter, e.g., 1 / 3 the infrared beam spot 214” diameter. This spacing distance between impingement locations 141 can be varied by varying the pulse rate of the infrared laser beam 212”, the rate of translation of the infrared laser beam 212” and the coated substrate 120 relative to one another, or both. Without intending to be limited by theory, ¼ to ½ overlap between adjacent impingement locations 141 results in more continuous damage along the offset line 144 than if the impingement locations 141 were spaced completely apart. Figures 7A-7D Similar to the embodiments of Figures 8A-8C , the infrared laser beam 212” applies thermal energy to the coated substrate 120, inducing crack propagation along the plurality of defects 172 within the coated substrate 120, thereby separating the coated substrate 120 along the contour line 142.

[0131] Indeed, by irradiating the dummy region 126 of the coated substrate 120 with the annular infrared laser beam 212” along the offset line 144 as depicted in Figures 9A-9C , the cumulative fluence applied to the dummy region 126 by the infrared laser beam 212” follows a top-hat cumulative fluence profile in which 20% or less of the total energy applied to the dummy region 126 is applied to portions of the dummy region 126 that are not located between the inner orbital line 146 and the outer orbital line 148, and portions of the dummy region 126 that are located between the inner orbital line 146 and the outer orbital line 148 are impinged by a cumulative fluence that is greater than 80% of the maximum cumulative fluence applied to any portion of the dummy region 126. This top-hat cumulative fluence profile is graphically depicted in Figure 9D , in which the line 82 of the plot 80 depicts relative cumulative fluence as a function of position along portions of the dummy region 126. The relative cumulative fluence at the peak of the cumulative fluence profile is normalized to 1, and the balance of the cumulative fluence distribution is scaled proportionally.

[0132] Based on the above description, it should be understood that a transparent workpiece and a coated substrate can be separated by laser while limiting or preventing damage to the main area of ​​the coated substrate. The methods described herein include forming a series of defects in the transparent workpiece using a pulsed laser beam, and separating the transparent workpiece and coating along the series of defects using an infrared laser beam formed along the boundary between the main area and a dummy area. The methods described herein include: translating the infrared laser beam along an oscillating path on the dummy area to separate the coated substrate; modifying the energy distribution of the infrared laser beam to a top-cap energy distribution and guiding the modified laser beam onto the dummy area to separate the coated substrate; and forming the infrared laser beam into a ring shape and guiding the ring-shaped infrared laser beam onto the dummy area to separate the coated substrate. As described herein, these methods use techniques sufficient to induce crack propagation of defects set in the coated substrate along the boundary between the main area and the dummy area in a single process step, directing thermal energy to the dummy area of ​​the coated substrate.

[0133] As used herein, the term “about” means that a quantity, dimension, formulation, parameter, and other quantity and characteristic is not, and does not need to be, exact, but may be approximate and / or larger or smaller as required, reflecting tolerances, conversion factors, rounding, measurement errors, and other factors known to those skilled in the art. When the term “about” is used at the endpoints of a value or range, the specific value or endpoint referred to is included. Regardless of whether the endpoints of a numerical value or range in the specification are marked with “about,” two embodiments are described: one modified by “about” and one not modified by “about.” It will also be understood that each endpoint of a range is significant relative to the other endpoint and independent of the other endpoint.

[0134] The directional terms used herein (e.g., up, down, right, left, front, back, top, bottom) are used only with reference to the accompanying drawings and are not intended to imply absolute orientation.

[0135] Unless otherwise expressly stated, any method described herein shall never be construed as requiring its steps to be performed in a particular order, nor requiring any particular orientation of the apparatus. Therefore, in any instance where a method claim does not actually describe the order in which its steps are to be followed, or any apparatus claim does not actually describe the order or orientation of the components, or where the claims or description do not otherwise specifically state that these steps will be limited to a particular order, or where no particular order or orientation / orientation of the apparatus components is described, no inference shall be made of any order or orientation. This applies to any possible non-explicit basis for interpretation, including: logical matters relating to the arrangement of steps, the flow of operations, the order of components, or the orientation of components; general meanings derived from grammatical organization or punctuation; and the number or type of embodiments described in the specification.

[0136] As used herein, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a component" includes aspects with two or more such components unless the context clearly indicates otherwise.

[0137] Various modifications and changes can be made to the embodiments described herein without departing from the spirit and scope of the claimed subject matter. Accordingly, it is intended that the specification cover all such modifications and changes as fall within the scope of the various embodiments described herein and their equivalents.

Claims

1. A method of separating a coated substrate, the method comprising: directing an infrared laser beam onto a first surface of the coated substrate, wherein: the coated substrate comprises a coating layer disposed on a transparent workpiece; a plurality of defects are disposed within the coated substrate, extend into both the coating layer and the transparent workpiece, and are disposed along a contour line separating a primary region of the coated substrate from a dummy region of the coated substrate; and the infrared laser beam projects an infrared beam spot onto the first surface of the coated substrate; and at least one of the coated substrate and the infrared laser beam is translated relative to the other such that the infrared beam spot traces an oscillating path, wherein: the oscillating path follows an offset line in a direction of translation and oscillates between an inner orbital line and an outer orbital line; the oscillating path is disposed on the dummy region of the coated substrate; and the infrared laser beam applies thermal energy to the plurality of defects disposed on the coated substrate and induces separation of the coated substrate along the contour line.

2. The method of claim 1, wherein, In tracing the oscillating path, the infrared beam spot applies thermal energy to the dummy region of the coated substrate without melting or ablating the coating layer of the primary region of the coated substrate.

3. The method of claim 1, wherein, the oscillating path follows a pendulum oscillation in which the oscillating path rotationally oscillates between the inner orbital line and the outer orbital line while following the offset line in the direction of translation.

4. The method of claim 1, wherein, the coating layer comprises a polymer or a metal oxide.

5. The method of claim 1, further comprising: forming the plurality of defects in the coated substrate prior to directing the infrared laser beam onto the first surface of the coated substrate by directing a pulsed laser beam into the coated substrate, wherein: the pulsed laser beam forms a pulsed laser beam focal line that extends into the coating layer and the transparent workpiece, the pulsed laser beam focal line induces absorption in the coating layer and the transparent workpiece, the induced absorption creates individual defects in the coated substrate; and the pulsed laser beam focal line comprises: a wavelength λ; Spot size w o ; and greater than F D Rayleigh range Z R where F D is a dimensionless divergence factor including a value of 10 or greater; and at least one of the coated substrate and the pulsed laser beam is translated relative to the other along the contour line to form the plurality of defects in the coated substrate.

6. A method of separating a coated substrate, the method comprising: directing an infrared laser beam onto a first surface of the coated substrate, wherein: the coated substrate comprises a coating layer disposed on a transparent workpiece; a plurality of defects are disposed within the coated substrate, extend into both the coating layer and the transparent workpiece, and are disposed along a contour line separating a primary region of the coated substrate from a dummy region of the coated substrate; the infrared laser beam projects an infrared beam spot onto the first surface of the coated substrate; and the infrared beam spot comprises an energy distribution in which 20% or less of a total energy of the infrared beam spot is less than 80% of a maximum fluence of the infrared beam spot; and the infrared beam spot is configured to apply thermal energy to the plurality of defects disposed on the coated substrate and induce separation of the coated substrate along the contour line. at least one of the coated substrate and the infrared laser beam is translated relative to one another such that the infrared beam spot follows an offset line, wherein: the offset line is disposed on the dummy region of the coated substrate and is offset from the contour line such that an inner region of the infrared beam spot is projected onto the dummy region; the infrared laser beam applies thermal energy to the plurality of defects disposed on the coated substrate and induces separation of the coated substrate along the contour line; wherein: at least one of the coated substrate and the infrared laser beam is translated relative to one another such that the infrared beam spot traces an oscillating path that follows the offset line in a direction of translation and oscillates between an inner orbital line and an outer orbital line; and the oscillating path is disposed on the dummy region of the coated substrate.

7. The method of claim 6, wherein, the infrared laser beam traverses a non-diffractive optical element prior to irradiating the coated substrate.

8. A method for separating a coated substrate, the method comprising: directing an infrared laser beam onto a first surface of the coated substrate, wherein: the coated substrate comprises a coating layer disposed on a transparent workpiece; a plurality of defects are disposed within the coated substrate, extend into both the coating layer and the transparent workpiece, and are disposed along a contour line that separates a primary region of the coated substrate from a dummy region of the coated substrate; and the infrared laser beam projects an infrared beam spot onto the first surface of the coated substrate; and the infrared beam spot comprises a ring shape; and at least one of the coated substrate and the infrared laser beam is translated relative to one another such that the infrared beam spot follows an offset line, wherein: the offset line is disposed on the dummy region of the coated substrate and is offset from the contour line such that the infrared beam spot is projected onto the dummy region; and the infrared laser beam applies thermal energy to the coated substrate, thereby inducing separation of the coated substrate along the contour line; wherein: at least one of the coated substrate and the infrared laser beam is translated relative to one another such that the infrared beam spot traces an oscillating path that follows the offset line in a direction of translation and oscillates between an inner orbital line and an outer orbital line; and 9. The method of claim 8, wherein, the oscillating path is disposed on the dummy region of the coated substrate. the infrared laser beam traverses a non-diffractive optical element prior to irradiating the coated substrate. the infrared laser beam traverses a non-diffractive optical element prior to irradiating the coated substrate. the infrared laser beam traverses a non-diffractive optical element prior to irradiating the coated substrate, wherein: the non-diffractive optical element comprises a focal plane that is a focal distance away from the non-diffractive optical element; and the first surface of the coated substrate is positioned relative to the non-diffractive optical element such that the focal plane is offset from the first surface of the coated substrate. the infrared laser beam traverses a non-diffractive optical element prior to irradiating the coated substrate. the infrared laser beam traverses a non-diffractive optical element prior to irradiating the coated substrate. the infrared laser beam traverses a non-diffractive optical element prior to irradiating the coated substrate, wherein: the non-diffractive optical element comprises a focal plane that is a focal distance away from the non-diffractive optical element; and the first surface of the coated substrate is positioned relative to the non-diffractive optical element such that the focal plane is offset from the first surface of the coated substrate.

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