METHODS FOR LASER PROCESSING THE SAME

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Application No. 15/288,071 , filed on October 7, 2016, which is incorporated herein by reference in its entirety.

FIELD OF THE DISCLOSURE

[0002] The disclosure relates generally to electrochromic coated glass articles and more particularly to methods for laser processing such articles. The disclosure also relates to insulated glass units comprising glass substrates coated with an electrochromic layer.

BACKGROUND

[0003] Glass substrates coated with electrochromic films may be useful in a variety of applications, including architectural and automotive applications. For example, electrochromic films may be used to vary light intensity and/or light absorption in a room or vehicle. Insulated glass units (IGUs) can comprise two sheets of glass with a perimeter seal forming a cavity between the glass sheets, which can be filled with an insulated gas such as argon to improve the energy rating of the IGU. In certain applications, one of the glass sheets in the IGU may be coated with an electrochromic layer. Such coated IGUs may additionally include one or more components for applying voltage to the electrochromic layer, e.g., bus bars, thereby providing a tinting effect which may lower the transmission of various wavelengths and/or heat by the IGU.

[0004] During the manufacture of IGUs or any other glass articles comprising an electrochromic layer, the electrochromic layer may be applied to the glass after cutting and grinding steps due to the sensitivity of these films to moisture and particles generated during these steps. For instance, exposure of electrochromic films to aqueous coolants used during the grinding process may result in blistering and/or breakdown of the films, thereby inhibiting their functionality and/or aesthetic qualities. As such, for traditional IGU production, a glass sheet is often first cut to the desired IGU shape and size and then coated with the electrochromic film ("cut-and-coat"), rather than coating a large glass substrate with an electrochromic film and then cutting the coated substrate to size ("coat-and-cut").

[0005] However, the cut-and-coat process can result in a glass substrate having a significant area that is not coated or is not uniformly coated by the electrochromic layer due to fixturing. For example, the components for positioning and holding the glass substrate in place in the coating apparatus may interfere with the ability to coat the glass substrate edge-to-edge. Additionally, the coat-and-cut process may have reduced manufacturing flexibility, because the fixturing must is specific to each glass substrate shape and/or size and must be adjusted to accommodate different glass shapes and/or sizes. In contrast, a coat-and-cut process can implement a single standard fixturing for a large glass substrate and the glass substrate can be subsequently cut to size (coat-and-cut).

[0006] Accordingly, it would be advantageous to provide methods for producing glass substrates coated with an electrochromic film which do not substantially damage the electrochromic film and/or do not result in glass substrates comprising uncoated or non-uniformly coated regions. Additionally, it would be advantageous to provide methods for manufacturing such electrochromic coated glass articles which can exhibit increased manufacturing flexibility and/or reduced manufacturing cost, e.g., methods which can be used to coat a glass substrate having a generic shape and/or size and subsequently cut the glass to a specific shape and/or size for a desired application.

SUMMARY

[0007] The disclosure relates, in various embodiments, to glass articles comprising a first surface, an opposing second surface, and an electrochromic coating disposed on at least a portion of the second surface, wherein upon application of voltage to the glass article a first region of a coated portion of the glass substrate has a first visible light transmission that is less than a second visible light transmission of a second region of the coated portion. According to some embodiments, the first region may be tinted and the second region may not be tinted upon application of voltage. In various embodiments, the first and second regions may be separated by a contour comprising a plurality of defect spots or lines, In some embodiments, the defect lines may be linear or curved when viewed orthogonally to the first or second surface. According to additional embodiments, the first and/or second regions may comprise a pattern on the glass article when viewed orthogonally to the first or second surface.

[0008] Further disclosed herein are glass articles comprising a first surface, an opposing second surface, and an electrochromic coating disposed on substantially all of the second surface, wherein the electrochromic coating comprises a laser damaged peripheral region proximate at least one edge of the glass article, the laser damaged peripheral region having a width of less than about 10 mm, 1 mm, or 0.1 mm. Insulated glass units comprising such glass articles are further disclosed herein.

[0009] In an aspect (1 ), the disclosure provides an electrochromic glass article comprising: a glass substrate comprising a first surface, an opposing second surface, and one or more edges, wherein at least one or more of the one or more edges comprises a laser-modified edge; an electrochromic coating disposed on at least a portion of the second surface, and comprising at least two electrically discontinuous regions, each having a contour; and wherein the two electrically discontinuous regions are separated by a laser-modified discontinuity line having a width from about 0.1 pm to about 25 pm. In an aspect (2), the disclosure provides the electrochromic glass article of aspect (1 ), wherein the electrochromic coating comprises tungsten oxide. In an aspect (3), the disclosure provides the electrochromic glass article of aspect (1 ) or (2), wherein the electrically discontinuous regions are not substantially laser damaged. In an aspect (4), the disclosure provides the electrochromic glass article of any of aspects (1 )-(3), wherein the second surface of the glass substrate proximate to the laser- modified discontinuity line is not substantially laser damaged. In an aspect (5), the disclosure provides the electrochromic glass article of aspect (4), wherein the contour of at least one of the at least two electrically discontinuous regions is non-linear. In an aspect (6), the disclosure provides the electrochromic glass article of any of aspects (1 )- (5), wherein the laser cut discontinuity is a continuous line formed by a laser with a pulse width from 10 ^"10 to 10 ^"15 seconds at FWHM. In an aspect (7), the disclosure provides the electrochromic glass article of any of aspects (1 )-(6), wherein the second region comprises a pattern in the first region or the first region comprises a pattern in the second region. In an aspect (8), the disclosure provides the electrochromic glass article of any of aspects (1 )-(7), wherein the glass article comprises a glass sheet having a thickness ranging from about 0.1 mm to about 10 mm. In an aspect (9), the disclosure provides the electrochromic glass article of any of aspects (1 )-(8), wherein one of the at least two electrically discontinuous regions comprises a region of the second surface proximate to the one or more edges of the glass substrate. In an aspect (10), the disclosure provides the electrochromic glass article of aspect (9), wherein the electrically discontinuous region proximate to the one or more edges of the glass substrate has a width of less than about 0.1 mm. In an aspect (1 1 ), the disclosure provides the electrochromic glass article of aspect (9), wherein the he electrically discontinuous region proximate to the one or more edges of the glass substrate comprises about 5% or less of the coated portion of the glass article.

[0010] In an aspect (12), the disclosure provides a glass article comprising a first surface, an opposing second surface, and an electrochromic coating disposed on substantially all of the second surface, wherein the electrochromic coating comprises a laser damaged peripheral region proximate at least one edge of the glass article, the laser damaged peripheral region having a width of less than about 0.1 mm. In an aspect (13), the disclosure provides the glass article of aspect (12), wherein the laser damaged peripheral region comprises about 5% or less of the second surface of the glass article. In an aspect (14), the disclosure provides the glass article of aspect (12) or (13), wherein the at least one edge has a linear or curved contour. In an aspect (15), the disclosure provides the glass article of any of aspects (12)-(14), wherein the glass article comprises a glass sheet having a thickness ranging from about 0.1 mm to about 10 mm. In an aspect (16), the disclosure provides the glass article of any of aspects (12)-(15), wherein a coated portion of the second surface comprises a first region and a second region, and wherein upon application of voltage to the glass article the first region has a first visible light transmission that is less than a second visible light transmission of the second region. In an aspect (17), the disclosure provides the glass article of aspect (16), wherein the first and second regions are separated by a discontinuity line comprising one or more laser lines. In an aspect (18), the disclosure provides the glass article of aspect (17), wherein the contour is linear or curved. [0011] In an aspect (19), the disclosure provides an insulated glass unit comprising the electrochromic glass article of any of aspects (1 )-(1 1 ).

[0012] In an aspect (20), the disclosure provides an insulated glass unit comprising the glass article of any of aspect (12)-(18).

[0013] Additional features and advantages of the disclosure will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the methods as described herein, including the detailed description which follows, the claims, as well as the appended drawings.

[0014] It is to be understood that both the foregoing general description and the following detailed description present various embodiments of the disclosure, and are intended to provide an overview or framework for understanding the nature and character of the claims. The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments of the disclosure and together with the description serve to explain the principles and operations of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The following detailed description can be further understood when read in conjunction with the following drawings, wherein, when possible, like numerals refer to like components, it being understood that the appended figures are not necessarily drawn to scale.

[0016] FIGS. 1A-B illustrate a glass substrate with a contour comprising a plurality of defect lines;

[0017] FIGS. 2A-B illustrate the positioning of a laser beam focal line to induce absorption in a glass substrate along the focal line;

[0018] FIG. 3 illustrates an optical assembly for focusing a laser beam into a laser beam focal line according to various embodiments of the disclosure;

[0019] FIGS. 4A-C illustrate a glass substrate comprising electrochromic coated and uncoated regions according to certain embodiments of the disclosure. DETAILED DESCRIPTION

Methods

[0020] The glass articles disclosed herein can be manufactured using one or more methods for creating small (e.g., 100, 10, or 1 micron or smaller) "holes" in the glass for the purpose of drilling, cutting, separating, perforating, or otherwise processing the materials optionally in combination with one or more methods of inducing defects or discontinuities in a electrochromic layer that is coated on the glass. In certain embodiments, an ultrashort (i.e., pulse width from 10 ^"10 to 10 ^"15 second FWHM, e.g., nanosecond to femtosecond) pulsed laser beam (operating at wavelengths such as 1064, 532, 355 or 266 nm, for example) can be focused to an energy density above a threshold at which defects can be created in the region of focus at the surface of or within the glass. By repeating the process, a series of laser-induced defects aligned along a predetermined path or contour can be created. In some embodiments, the laser-induced defect lines can be spaced sufficiently close together, such that a controlled region of mechanical weakness within the glass can be created and optionally used to fracture or separate (mechanically or thermally) the material along the defined contour. For example, after contact with the ultrashort pulsed laser, the material may be contacted with a second laser beam, e.g., an infrared laser such as a carbon dioxide (CO2) laser, or other source of thermal stress, to separate the glass into one or more portions.

[0021] According to various embodiments, one or more vertical fault or defect spots, series of spots, or lines can be created in a glass substrate, which can delineate a contour or path of least resistance along which the substrate can be separated to define a desired shape, wherein the contour comprises a plurality of defect lines or regions extending from the first surface to the opposing second surface of the glass substrate. The substrate to be processed may be irradiated with an ultrashort pulsed laser beam (e.g., pulse width < 100 psec; wavelength < 1064 nm) that may be condensed into a high aspect ratio focal line penetrating all or a portion of the substrate thickness.

[0022] Within this volume of high energy density, the substrate may be modified via nonlinear effects, which can be triggered by the high optical intensity. Below this intensity threshold, the substrate may be transparent to the laser radiation and may not be modified to produce defect lines. As used herein, a substrate is "substantially transparent" to the laser wavelength when the substrate absorption is less than about 10%, e.g., less than about 5%, or less than about 1 %, per mm of substrate depth at the wavelength of the laser. By scanning the laser over a desired contour or path, one or more narrow defect lines can be created in the substrate and the contour can define a perimeter or shape along which the glass substrate can be separated and/or a tinted or untinted region of the coated substrate.

[0023] The ultrashort pulsed laser can create multi-photon absorption ("MPA") in substantially transparent materials such as glass. MPA is the simultaneous absorption of two or more photons of identical or different frequencies in order to excite a molecule from one state, usually the ground state, to a higher energy electronic state. The energy difference between the involved lower and upper states of the molecule is equal to the sum of the energies of the two photons. MPA, also called induced absorption, can be a second or third-order process, for example, that is several orders of magnitude weaker than linear absorption. It differs from linear absorption in that the strength of induced absorption can be proportional to the square of the light intensity, for example, and thus it is a nonlinear optical process.

[0024] The pulsed laser beam may have a wavelength chosen from those at which the substrate is substantially transparent, e.g., wavelengths less than or equal to about 1064 nm, such as 532, 355, or 266 nanometers, including all ranges and subranges therebetween. Exemplary power levels for the pulsed laser can range, in some embodiments, from about 10 W to about 150 W, such as from about 25 W to about 125 W, or from about 50 W to about 100 W, including all ranges and subranges therebetween. According to various embodiments, the pulsed laser beam can have a pulse duration of less than 10 nanoseconds, for example about 100 picoseconds. In some embodiments the pulsed laser beam has a pulse duration from greater than about 1 picosecond to less than about 100 picoseconds, e.g., ranging from about 5 picoseconds to about 50 picoseconds, from about 10 picoseconds to about 30 picoseconds, or from about 15 picoseconds to about 20 picoseconds, including all ranges and subranges therebetween. In additional embodiments, the pulse repetition rate of the pulsed laser beam can range from about 1 kHz to about 4 MHz, such as from about 10 kHz to about 650 kHz, from about 50 kHz to about 500 kHz, from about 100 kHz to about 400 kHz, or from about 200 kHz to about 300 kHz, including all ranges and subranges therebetween.

[0025] The pulsed laser beam can operate, in some embodiments, in a single pulse mode or, in other embodiments, in burst mode. In the latter embodiments, a pulse burst can comprise two or more pulses, such as, for example, 3, 4, 5, 10, 15, 20, 25, or more pulses per burst, including all ranges and subranges therebetween. A duration between individual pulses in a pulse burst may range, for instance, from about 1 nanosecond to about 50 nanoseconds, such as from about 10 nanoseconds to about 30 nanoseconds, or from about 20 nanoseconds to about 40 nanoseconds, including all ranges and subranges therebetween. A duration between pulse bursts can range, in certain embodiments, from about 1 microsecond to about 20 microseconds, such as from about 5 microseconds to about 10 microseconds, including all ranges and subranges therebetween. Accordingly, a burst repetition frequency of the pulsed laser beam can range from about 1 kHz to about 200 kHz, such as from about 20 kHz to about 150 kHz, or from about 50 kHz to about 100 kHz, including all ranges and subranges therebetween.

[0026] In burst mode, an average laser power per burst can range from about 50 J/burst to about 1000 J/burst, such as from about 100 J/burst to about 750 j/burst, from about 200 J/burst to about 500 J/burst, or from about 250 J/burst to about 400 J/burst, including all ranges and subranges therebetween. According to additional embodiments, the average laser power applied to a given material can be measured as J/burst per mm of material and can, for instance, be greater than about 40 J/burst per unit thickness (mm) of a given material (e.g., glass), such as ranging from about 40 pJ/burst/mm to about 2500 pJ/burst/mm, from about 100 pJ/burst/mm to about 2000 pJ/burst/mm, from about 250 pJ/burst/mm to about 1500 pJ/burst/mm, or from about 500 pJ/burst/mm to about 1000 pJ/burst/mm, including all ranges and subranges therebetween. For example, a 0.1 -0.2 mm thick Corning Eagle XG ^® glass substrate can be processed using a 200 J/burst pulsed laser to give an exemplary laser power of 1000-2000 pJ/burst/mm. In another non-limiting example, a 0.5-0.7 mm thick Corning Eagle XG glass substrate can be processed using a 400-700 pJ/burst pulsed laser to give an exemplary laser power of 570-1400 pJ/burst/mm.

[0027] According to non-limiting embodiments, the glass substrate and pulsed laser beam may be translated relative to each other, e.g., the glass substrate may be translated relative to the pulsed laser beam and/or the pulsed laser beam may be translated relative to the glass substrate, to create a contour. In one specific embodiment, the glass substrate is translated and the pulsed laser is applied thereto while the pulsed laser is itself translated. For example, in roll to roll processing, the glass substrate may be very long, for example tens of meters long or more, and translate substantially continuously during laser processing. The laser is translated at the appropriate speed and along the appropriate vectors to create one or more contours in the glass substrate. Either the substrate or the laser may change their speed during this processing.

[0028] The contour can comprise a plurality of defect lines that may trace or define the perimeter of a shape to be created, either by subsequent separation or by subsequent application of voltage (e.g. , tinting). The translation or scan speed can depend on various laser processing parameters including, for instance, laser power and/or repetition rate. Exemplary translation or scan speeds can range, for instance, from about 1 mm/s to about 5000 mm/s, such as from about 100 mm/s to about 4000 mm/s, from about 200 mm/s to about 3000 mm/s, from about 300 mm/s to about 2500 mm/s, from about 400 mm/s to about 2000 mm/s, or from about 500 mm/s to about 1000 m/s, including all ranges and subranges therebetween.

[0029] The repetition rate and/or scan speed of the pulsed laser beam can be varied to create a desired periodicity (or pitch) between defect lines. In some embodiments, the defect lines may be spaced apart by about 0.5 pm to about 25 pm, such as from about 1 pm to about 20 pm, from about 2 pm to about 15 pm, from about 3 pm to about 12 pm, from about 4 pm to about 10 pm, or from about 5 pm to about 8 pm, including all ranges and subranges therebetween. For example, for a linear cutting (or scan) speed of 300 mm/s, a 3 m periodicity between defect lines corresponds to a pulsed laser having a burst repetition rate of at least 100 kHz. Similarly, for a scan speed of 600 mm/s, a 3 μι periodicity between defect lines corresponds to a pulsed laser having a burst repetition rate of at least 200 kHz.

[0030] Additionally, the dimensions of the defect lines can be affected, for instance, by the laser focusing parameters, such as the length of the laser beam focal line and/or the average spot diameter of the laser beam focal line. The pulsed laser can be used, for example, to create one or more defect lines having a relatively high aspect ratio (length : diameter), such that a very thin, long defect line can be produced that extends, in some embodiments, from the first surface to the opposing second surface of the substrate. Such defect lines can, in principle, be created by a single laser pulse, or additional pulses can be used to increase the affected area (e.g., increased defect line length and/or width).

[0031] As generally illustrated in FIGS. 1A-B, methods for cutting a glass substrate 130 comprising an electrochromic layer 150 can comprise creating a contour or fault line 110 comprising a plurality of defect lines 120 in the substrate to be processed using a pulsed laser 140. The defect lines 120 may extend, for example, through the thickness of the glass substrate, e.g., approximately orthogonal to the major (flat) surfaces a, b of the glass sheet. While a linear contour, such as the contour 110 illustrated in FIG. 1A, can be created by translating the glass substrate 130 and/or pulsed laser 140 in one dimension, a curved or nonlinear contour can also be created by translating the glass substrate and/or pulsed laser in two dimensions. As shown in FIG. 1 B, the glass substrate 130 can then be separated along the contour 110 to produce two separate portions 130a and 130b, wherein the separated edges or surfaces are defined by the contour 110, each portion comprising an electrochromic layer 150.

[0032] Referring to FIGS. 2A-B, methods for laser processing a substrate can include focusing a pulsed laser beam 2 into a laser beam focal line 2b oriented along the beam propagation direction. A laser (not shown) may emit pulsed laser beam 2, which may have a portion 2a incident to an optical assembly 6. The optical assembly 6 may convert the incident portion 2a of the laser beam into a laser beam focal line 2b along the beam direction, which may have a length L and a diameter D. A substrate 1 may be positioned in the beam path to at least partially overlap with the laser beam focal line 2b, which may thus be directed into the substrate 1. A first surface 1a may be positioned to face the optical assembly 6, whereas an opposing second surface 1b may be positioned to face away from the optical assembly 6, or vice versa. A thickness d of the substrate may extend perpendicularly between surfaces 1a and 1b.

[0033] As depicted in FIG. 2A, substrate 1 may be aligned perpendicular to the longitudinal axis of the laser beam and the focal line 2b produced by the optical assembly 6. In various embodiments (as depicted), the focal line 2b may begin before the surface 1a of the substrate 1 and may not extend beyond surface 1 b. Of course other focal line orientations can be used, such that the focal line 2b begins after the surface 1a and/or does extend beyond surface 1 b (not shown). The area in which the laser beam focal line and substrate overlap may be modified by nonlinear multiphoton or induced absorption of the laser energy, assuming sufficient laser intensity along the laser beam focal line 2b, which intensity can be produced by focusing the laser beam 2 on a section of length I, i.e., a line focus of length I.

[0034] The induced absorption can produce defect line formation in the substrate material along section 2c. In some embodiments, the defect line may be a microscopic series of (e.g. , 100 nm < diameter < 10 pm) "holes" (also called a perforation or defect line). According to various embodiments, individual perforations can be created at rates of several hundred kHz (several hundred thousand perforations per second). By translating the substrate and pulsed laser relative to each other, these perforations can be created adjacent to one another with a desired spatial separation (also referred to as periodicity or pitch). The periodicity of the defect lines can be selected as desired to facilitate separation of the substrate and/or to create a desired tinting effect. Exemplary periodicity between the defect lines can range, for instance, from about 0.5 pm to about 25 pm, such as from about 1 pm to about 20 pm, from about 2 pm to about 15 pm, from about 3 pm to about 12 pm, from about 4 pm to about 10 pm, or from about 5 m to about 8 pm, including all ranges and subranges therebetween.

[0035] In certain non-limiting embodiments, the defect line may be a "through hole" or open channel extending from the first surface 1a to the opposing second surface 1b, e.g. , extending across the entire thickness d of the substrate 1. Defect line formation can also extend across a portion of the substrate thickness, as indicated by section 2c having length L in FIG. 2A. The length L of section 2c thus corresponds to the length of the overlap between the laser beam focal line 2b with the substrate 1 and the length of the resulting defect line. The average diameter D of section 2c may correspond more or less to the average diameter of the laser beam focal line 2b. Referring to FIG. 2B, the substrate 1 exposed to the laser beam 2 in FIG. 2A will eventually expand due to induced absorption of the laser energy such that a corresponding induced tension in the material may lead to microcrack formation. The induced tension may be greatest at surface 1a, according to various embodiments.

[0036] As defined herein, the width of a defect line corresponds to the internal width of the open channel or diameter air hole produced in the glass substrate. For example, in some embodiments, the width of the defect line may range from about 0.1 pm to about 5 pm, such as from about 0.25 pm to about 4 pm, from about 0.5 pm to about 3.5 pm, from about 1 pm to about 3 pm, or from about 1 .5 pm to about 2 pm, including all ranges and subranges therebetween. The width of a defect line can, in some embodiments, be as large as the average spot diameter of the laser beam focal line, e.g., the average spot diameter of the laser beam focal line may also range from about 0.1 pm to about 5 pm, such as from about 0.25 pm to about 4 pm, from about 0.5 pm to about 3.5 pm, from about 1 pm to about 3 pm, or from about 1 .5 pm to about 2 pm, including all ranges and subranges therebetween. In embodiments in which the glass substrate is separated along a contour comprising a plurality of defect lines, the defect lines may be potentially viewed along the cut edge(s) of the separated portions, and these regions can have widths comparable to the widths of the defect lines, e.g., from about 0.1 pm to about 5 pm.

[0037] The pulsed laser beam can be focused into a laser beam focal line having any desired length I, which can vary, e.g., depending on the selected optical assembly configuration. In some embodiments, the laser beam focal line length can range, for example, from about 0.01 mm to about 100 mm, such as from about 0.1 mm to about 50 mm, from about 0.5 mm to about 20 mm, from about 1 mm to about 10 mm, from about 2 mm to about 8 mm, or from about 3 mm to about 5 mm, including all ranges and subranges therebetween. In various embodiments, the laser beam focal line length I can correspond to the thickness d of the substrate, can be less than the thickness d, or can be greater than the thickness d of the substrate. As such, in some embodiments, the methods disclosed herein can be used to process or cut more than one substrate, such as a stack of two or more substrates. According to non-limiting embodiments, the pulsed laser beam can perforate a stack of glass substrates up to a total thickness of about 100 mm or greater, e.g., from 20 μηι to about 200 mm, with a single laser pass, even in instances where one or more air gaps exist between the substrates in various locations. For example, each substrate of a stack of 200 substrates, each substrate being 0.5 mm thick, may be perforated by a single pass of the laser. For example, each substrate having an electrochromic film approximately 1 micron (0.001 mm) thick, would make a stack of 200 such substrates 100.2 mm thick (100 mm of glass and 0.2 mm of electrochromic film). Additionally, some embodiments may further comprise additional coatings and/or protective materials between the glass substrates that are optically clear and allow the perforation of multiple layers. Such coatings include, but are not limited to, S1O2, AI2O3, and organic and inorganic polymers, such as siloxanes.

[0038] The defect line or plurality of defect lines can be created using various methods. For example, various devices can be used to focus a laser beam to create a laser beam focal line. A laser beam focal line may be generated, for example, by transmitting a Gaussian laser beam into an axicon lens to create a Gauss-Bessel laser beam profile. A Gauss-Bessel beam may diffract more slowly than a Gaussian beam (e.g., may maintain single micron spot sizes for ranges of hundreds of microns or millimeters as oppose to a few tens of microns or less). The depth or length of focus intensity for a Gauss-Bessel beam may thus be much larger than that of a Gaussian beam. Other slowly diffracting or non-diffracting beams may also be used or created using optical elements, such as Airy and Bessel beams. Exemplary optical assemblies for generating a laser beam focus line are provided in U.S. Patent Application Nos. 14/529,520 and 14/530,457, which are incorporated by reference herein in their entireties. Focusing can be carried out, e.g., using any variety of donut-shaped laser beams, spherical lenses, axicon lenses, diffractive elements, or any other suitable method or apparatus to form a linear region of high intensity. The type of pulsed laser (e.g., picosecond, femtosecond, etc.) and/or its wavelength (e.g., IR, UV, green, etc.) can also be varied, so long as sufficient intensity is created to create breakdown of the substrate material due to nonlinear optical effects.

[0039] FIG. 3 illustrates one exemplary optical assembly 6 that can be used to focus a pulsed laser beam 2 into a laser beam focal line 2b having length I and directed into a glass substrate 1 having an electrochromic layer 7. The optical assembly 6 can include, for example, an axicon lens 3, a collimating lens 4, and a focusing lens 5. The focal length of each lens in the optical assembly can be varied to produce a laser beam focal line having a desired diameter and/or length. For example, the focusing lens 5 can have a focal length ranging from about 10 mm to about 50 mm, such as from about 20 mm to about 40 mm, or from about 25 mm to about 30 mm, including all ranges and subranges therebetween. The collimating lens 4 may similarly have a focal length that ranges from about 50 mm to about 200 mm, such as from about 75 mm to about 150 mm, or from about 100 mm to about 125 mm, including all ranges and subranges therebetween.

[0040] In various non-limiting embodiments, an axicon lens 3 may be incorporated into the optical lens assembly 6 to create a high intensity region of high aspect ratio, e.g., taper-free laser microchannels, using ultrashort Bessel beams (of picosecond or femtosecond duration). An axicon is a conically cut lens capable of forming a spot source on a line along the optical axis (e.g., transforming a laser beam into a ring). Axicons and their configurations are known to those skilled in the art and may, for example, have cone angles ranging from about 5° to about 20°, such as from about 10° to about 15°, including all ranges and subranges therebetween.

[0041] The axicon lens 3 can condense the laser beam having an original diameter D1 (e.g., about 1 -5 mm, such as about 2-3 mm) into a high intensity region of substantially cylindrical shape and high aspect ratio (e.g. , long length and small diameter) with a smaller diameter corresponding, e.g., to the focal line diameter D illustrated in FIG. 2A. The high intensity created within the condensed laser beam can result in a nonlinear interaction of the electromagnetic field of the laser and the substrate such that the laser energy is transferred to the substrate to effect formation of defect lines. However, in areas of the substrate where the laser intensity is not sufficiently high (e.g., the areas surrounding the central convergence line), the substrate may be transparent to the laser such that there is no mechanism for transferring energy from the laser to the substrate material. As such, there may be no damage or change in the areas of the glass substrate which are exposed to laser intensity below the nonlinear threshold.

[0042] After creating a contour comprising a plurality of defect lines or perforations using the pulsed laser beam, the glass substrate can optionally be separated into two or more portions using a second laser beam. The second laser beam may be used as a heat source to create a thermal stress zone around the contour, which may put the defect lines in tension thereby inducing separation. The second laser beam can emit any wavelength at which the glass substrate is not transparent, such as infrared wavelengths, e.g., greater than about 1064 nm. In some embodiments, the second laser beam can emit at wavelengths greater than about 5 pm, such as greater than about 10 pm. Suitable infrared lasers may include, for example, CO2 lasers and the like, which may be modulated or unmodulated. A non-limiting example of a second laser beam includes, but is not limited to, a modulated CO2 laser operating at a wavelength greater than about 10 pm, such as about 10.2 pm to about 10.7 pm, or from about 10.4 pm to about 10.6 pm, including all ranges and subranges therebetween.

[0043] With reference to FIGS. 1A-B, the second laser beam (not shown) can be contacted with the first surface a of the glass substrate 130 and translated along the contour 110 to separate the glass substrate into two or more portions 130a, 130b. The second surface b can comprise an electrochromic layer 150, which faces away from the surface a that is in contact with the second laser beam. The second laser beam can create a region of thermal stress on and around the contour 110, thus inducing separation of the glass substrate 130 along the contour 110 to create separate portions 130a, 130b

[0044] Exemplary power levels for the second laser beam can range, in some embodiments, from about 50 W to about 500 W, such as from about 100 W to about 400 W, from about 150 W to about 300 W, or from about 200 W to about 250 W, including all ranges and subranges therebetween. When operated in continuous (e.g., unmodulated) mode, the second laser beam may have a lower power than when operated in modulated mode. For instance, a continuous second laser beam may have a power level ranging from about 50 W to about 300 W, whereas a modulated second laser beam may have a power level ranging from about 200 W to about 500 W, although the respective laser powers can vary and are not limited to the given exemplary ranges. In additional embodiments, the average spot diameter of the second laser beam can range from about 1 mm to about 10 mm, such as from about 2 mm to about 9 mm, from about 3 mm to about 8 mm, from about 4 mm to about 7 mm, or from about 5 mm to about 6 mm, including all ranges and subranges therebetween. The heat generated by the second laser beam can result in a thermal stress region on and/or around the contour, this region having a diameter on the order of microns, e.g., less than about 20 pm, such as ranging from about 1 pm to about 20 pm, from about 2 pm to about 15 pm, from about 3 pm to about 10 pm, from about 4 pm to about 8 pm, or from about 5 m to about 6 pm, including all ranges and subranges therebetween.

[0045] According to various embodiments, the second laser beam may be modulated and can have a pulse duration of less than about 200 microseconds, such as greater than about 1 microsecond to less than about 200 microseconds, e.g., ranging from about 5 microseconds to about 150 microseconds, from about 10 microseconds to about 100 microseconds, from about 20 microseconds to about 80 microseconds, from about 30 microseconds to about 60 microseconds, or from about 40 microseconds to about 50 microseconds, including all ranges and subranges therebetween. According to various embodiments, a rise time of the modulated second laser beam can be less than about 150 microseconds, such as ranging from about 10 microseconds to about 150 microseconds, from about 20 microseconds to about 100 microseconds, from about 30 microseconds to about 80 microseconds, from about 40 microseconds to about 70 microseconds, or from about 50 microseconds to about 60 microseconds, including all ranges and subranges therebetween.

[0046] In additional embodiments, the pulse repetition rate (or modulation speed) of the modulated second laser beam can range from about 1 kHz to about 100 kHz, such as from about 5 kHz to about 80 kHz, from about 10 kHz to about 60 kHz, from about 20 kHz to about 50 kHz, or from about 30 kHz to about 40 kHz, including all ranges and subranges therebetween. According to non-limiting embodiments, the pitch or periodicity between the second laser beam pulses can range from about 1 pm to about 100 pm, such as from about 5 pm to about 90 pm, from about 10 pm to about 80 pm, from about 20 m to about 70 pm, from about 30 pm to about 60 pm, or from about 40 pm to about 50 pm, including all ranges and subranges therebetween.

[0047] In certain embodiments, the first surface of the glass substrate can be contacted with the second laser beam in a single pass or, in other embodiments, multiple passes can be made. For example, the second laser beam can be translated relative to the glass substrate, or vice versa, using anywhere from 1 to 10 passes, such as 2 to 9 passes, 3 to 8 passes, 4 to 7 passes, or 5 to 6 passes, including all ranges and subranges therebetween. The translation speed can range from about 100 mm/s to about 1000 mm/s, such as from about 150 mm/s to about 900 mm/s, from about 200 mm/s to about 800 mm/s, from about 250 mm/s to about 700 mm/s, from about 300 mm/s to about 600 mm/s, or from about 400 mm/s to about 500 mm/s, including all ranges and subranges therebetween.

[0048] Another aspect comprises use of any of the processes above to create holes, voids, gaps, or other discontinuities in the electrochromic layer on a substrate while either not damaging or limiting damage to the underlying substrate. In such embodiments, the electrochromic layer 150 can be used to modify laser absorption or penetration depth. In some embodiments, the electrochromic layer 150 is placed in a colored or darkened state to increase its absorption of the laser light, and in such embodiments, the laser may be tuned to a wavelength that is close to the light absorption wavelength of the electrochromic layer 150. In such embodiments, the absorption of the electrochromic layer may aid in modification of the electrochromic layer, may impact laser penetration depth, or may increase or decrease the overall laser pulse power needed to modify the glass or electrochromic layer.

[0049] In creating discontinuities in the electrochromic layer, it is generally the case that the goal is to create two or more electrically separated regions. Therefore, a discontinuity line, defined as a laser-formed line expressly formed to electrically isolate two or more regions of an electrochromic layer on a substrate, typically needs to be continuous, meaning that it completely disconnects the two regions of the electrochromic layer from each other, and may require ablation of at least one layer of the electrochromic film. The laser power or energy levels needed to create the discontinuities in the electrochromic layer are typically much less than needed to create damage in the glass substrate. Either pulsed or continuous lasers can be used. Use of pulsed lasers can be advantageous in that the electrochromic material can be ablated without heating the electrochromic or substrate, avoiding damaging the adjacent, retained electrochromic materials or the temper of the glass substrate. Further, the wavelength of the laser can advantageously be targeted to the absorption of the electrochromic film, either in its lightened or darkened state. Further the beam can be focused through the substrate or opposite the substrate, depending on needs.

[0050] If pulsed, exemplary laser powers can range, in some embodiments, from about 0.25 W to about 150 W, such as from about 0.25 W to about 50 W, or from about 1 W to about 100 W, including all ranges and subranges therebetween. According to various embodiments, the pulsed laser beam can have a pulse duration from 100 nanosecond to 10 femtoseconds, for example about 100 picoseconds. In some embodiments the pulsed laser beam has a pulse duration from greater than about 1 picosecond to less than about 100 picoseconds, e.g., ranging from about 5 picoseconds to about 50 picoseconds, from about 10 picoseconds to about 30 picoseconds, or from about 15 picoseconds to about 20 picoseconds, including all ranges and subranges therebetween. In additional embodiments, the pulse repetition rate of the pulsed laser beam can range from about 1 kHz to about 4 MHz, such as from about 10 kHz to about 650 kHz, from about 50 kHz to about 500 kHz, from about 100 kHz to about 400 kHz, or from about 200 kHz to about 300 kHz, including all ranges and subranges therebetween.

[0051] Because the power levels for discontinuity creation in the electrochromic are much less, a continuous laser source can be used as well. Power levels for continuous lasers are from about 0.25 W to about 150 W, such as from about 0.25 W to about 50 W, or from about 1 W to about 100 W, including all ranges and subranges therebetween, primarily depending on wavelength, focus, and time the beam is targeted to a particular region. [0052] The discontinuity line can be approximately the same width as the laser used to make it. The width of the discontinuity line may range from about 0.1 pm to about 5 pm, such as from about 0.25 pm to about 4 pm, from about 0.5 pm to about 3.5 pm, from about 1 m to about 3 pm, or from about 1 .5 pm to about 2 pm, including all ranges and subranges therebetween. The width of a discontinuity line can, in some embodiments, be as large as the average spot diameter of the laser beam focal line, e.g., the average spot diameter of the laser beam focal line may also range from about 0.1 pm to about 5 pm, such as from about 0.25 pm to about 4 pm, from about 0.5 pm to about 3.5 pm, from about 1 pm to about 3 pm, or from about 1 .5 pm to about 2 pm, including all ranges and subranges therebetween.

Glass Articles

[0053] Disclosed herein are glass articles comprising a first surface, an opposing second surface, and an electrochromic coating disposed on at least a portion of the second surface, wherein upon application of voltage to the glass article a first region of a coated portion of the glass substrate has a first visible light transmission that is less than a second visible light transmission of a second region of the coated portion. Referring to FIG. 4A, the second surface of a glass article is illustrated, comprising an electrochromic layer on a portion E of the surface (shaded portion) and an uncoated portion U (not shaded) separated by line Z. According to various embodiments, the methods disclosed herein can be used to laser process the glass article of FIG. 4A to produce the glass articles of FIGS. 4B-C, as well as any desired variations thereof.

[0054] In some embodiments, the electrochromic layer comprises one or more inorganic materials. In some embodiments, the electrochromic layer comprises one or more tungsten oxides.

[0055] For example, a first pulsed laser can be used to create contour A1 (dashed line), also referred to herein as a laser "scribe" or "perforation." A first pulsed laser and a second laser can be traced along contour B1 (double line) to separate the glass into two portions to produce the glass article depicted in FIG. 4B as well as an uncoated remainder (not shown). Upon application of voltage to C1 , C1 of the coated portion E may be "tinted" and/or may have a reduced transmission (e.g., for visible wavelengths 400-700 nm) as compared to a second region C2 of the coated portion E, which may remain inactivated and unchanged (or untinted). Alternatively, if a voltage is applied to C2 and not C1 , it may perform similarly to C1 above. Both C1 and C2 are now capable of tinting independent of each other as the scribe line has electrically disconnected the layers from each other. .

[0056] The laser scribe along contour A1 serves to create a electrical barrier to the electrochromic effect between C1 and C2. As such, the glass article can comprise uncoated (e.g., untinted) portion U and a "new" untinted (but coated) region C2 which will not exhibit an electrochromic effect upon application of voltage to C1 even though it is coated with the electrochromic layer (and vice versa). The laser scribe or perforation process can thus be used to produce any desired pattern on a glass substrate including linear and curved contours, as well as patterns within the first or second regions. The contour or laser scribe can comprise a plurality of discontinuity lines as discussed above and can separate the respective regions to produce any desired visual effect without significantly damaging the electrochromic layer or the glass substrate. The width of the discontinuity line may range from about 0.1 pm to about 25 pm, such as from about 0.25 pm to about 10 pm, from about 0.5 pm to about 5 pm, from about 1 pm to about 3 pm, or from about 1 .5 m to about 2 pm, including all ranges and subranges therebetween.

[0057] In some embodiments, C2 may not, or may not substantially be, laser damaged. For instance, the electrochromic coating and/or glass substrate in this region may not be laser damaged or may exhibit a very small region of laser damage along the contour, as described in more detail below. Therefore, in certain embodiments, the contour produces two or more active devices from a single motherboard. Since the laser cuts are precise and the power can be controlled to produce very fine lines with little damage to the electrochromic film, the electrochromic layers in C1 and C2 are not damaged and very little electrochromic material is wasted.

[0058] In some embodiments, the formation of discontinuities in the electrochromic film can be used to eliminate the tinting effect in certain regions of the article. Current methods for eliminating a tinting effect in a given region of a coated substrate involve removing the coating, e.g., using laser ablation to "burn" off the coating in a desired area. However, such processes can be imprecise and can result in a large region of damage to both the electrochromic layer and underlying glass substrate. For example, to ensure that the electrochromic layer is completely removed from the desired region, several passes may be made using a high power laser, which can result in a wide region (or strip) along which the remaining electrochromic layer is damaged and/or the underlying glass substrate is damaged. Such laser damage regions can have a width on the order of tens of millimeters, such as greater than about 20 mm, greater than about 25 mm, or even greater than about 30 mm.

[0059] Further disclosed herein are glass articles comprising a first surface, an opposing second surface, and an electrochromic coating disposed on substantially all of the second surface, wherein the electrochromic coating comprises a laser damaged peripheral region proximate at least one edge of the glass article, the laser damaged peripheral region having a width of less than about 10, 1 , or 0.1 mm. Referring again to FIG. 4A, a first pulsed laser can be used to create contour A2 (dashed line), and a first pulsed laser and a second laser can be traced along contour B2 (double line) to separate the glass into two portions to produce the glass article depicted in FIG. 4C. Upon application of voltage, a first region C1 of the coated portion E may become tinted and/or may have a reduced transmission (e.g., for visible wavelengths 400-700nm) as compared to a second region C2 of the coated portion E, which may remain unchanged (or untinted).

[0060] Unlike contour B1 which cuts through the uncoated portion U, contour B2 cuts through the coated region E. Without wishing to be bound by theory, it is believed that the laser cutting methods disclosed herein can separate the coated glass article with minimal damage to the electrochromic layer. The laser processing methods disclosed herein may result in a relatively small region (the contour width) in which the electrochromic film is laser damaged and will not exhibit an electrochromic effect upon application of voltage. For example, the laser cutting process can create a laser damage zone L along the cut edge e that is relatively thin (e.g., less than about 0.1 mm). In some embodiments, the laser damage zone L can have a width that is less than about 10 mm, 1 mm, or 0.1 mm, such as less than about 9 mm, 8 mm, 5 mm, 1 mm, 0.5 mm, 0.1 mm, 0.09 mm, 0.08 mm, 0.07 mm, 0.06 mm, 0.05 mm, 0.04 mm, 0.03 mm, 0.02 mm, 0.01 mm, or less, e.g., ranging from about 0.01 mm to about 0.1 mm, including all ranges and subranges therebetween.

[0061] The glass articles disclosed herein can have a laser damage region that is relatively small compared to uncoated and/or damaged regions produced by comparative processes. For instance, the cut-and-coat process may result in significant areas that are uncoated due to interference from fixturing. Similarly, if the glass were coated then cut using traditional aqueous edge grinding methods, the damage to the electrochromic layer proximate the cut edge (e.g., blistering, etc.) would be far greater. Furthermore, if it is desired to eliminate the tinting effect on any portion of such substrates (either cut-and-coat or coat-and-cut) using prior art methods, the laser damage region produced during the ablation process would be much larger (e.g. , 20 mm or greater in width).

[0062] The glass articles herein can comprise at least one surface that is substantially coated with a functional electrochromic layer, e.g. , tinted edge-to-edge upon application of voltage, which was not previously possible using prior art methods. In certain embodiments, substantially all of a surface of the glass article may be coated with an electrochromic layer, which can comprise one or more laser damage regions (< 0.1 mm) along one or more edges of the article. For example, a surface of a glass substrate may be coated with an electrochromic layer and then the coated substrate may be separated along a single contour to remove any uncoated portions of the glass substrate (e.g., due to fixturing). The resulting glass article may thus be substantially coated with the electrochromic layer and can comprise a peripheral laser damaged region near the contour edge. In additional embodiments, the coated glass substrate can be separated along more than one contour and the resulting glass article can comprise more than one laser damaged region. Upon application of voltage, an edge- to-edge tinting effect may be observed, except for any laser damaged region at the edges. However, such laser damaged regions may be relatively small in comparison to the uncoated and/or damaged regions produced by prior art processes. According to various embodiments, the laser damaged region may comprise less than about 5% of the coated portion of the glass surface, such as less than about 4%, 3%, 2%, 1 %, 0.5%, 0.1 %, or 0.01 %, including all ranges and subranges therebetween, although as the size of the glass article decreases, the relative percentage of the surface occupied by the laser damaged region can increase.

[0063] The glass articles disclosed herein can comprise any glass known in the art that is suitable for automotive, architectural, and other similar applications. Exemplary glass substrates can include, but are not limited to, aluminosilicate, alkali- aluminosilicate, borosilicate, alkali-borosilicate, aluminoborosilicate, alkali- aluminoborosilicate, soda lime silicate, and other suitable glasses. In certain embodiments, the substrate may have a thickness ranging from about 0.1 mm to about 10 mm, such as from about 0.3 mm to about 5 mm, from about 0.5 mm to about 3 mm, or from about 1 mm to about 2 mm, including all ranges and subranges therebetween. Non-limiting examples of commercially available glasses suitable for use as a light filter include, for instance, EAGLE XG ^® Iris™, Lotus™, Willow ^® Gorilla ^® HPFS ^® and ULE ^® glasses from Corning Incorporated. Suitable glasses are disclosed, for example, in U.S. Patent Nos. 4,483,700, 5,674,790, and 7,666,51 1 , which are incorporated herein by reference in their entireties, which are incorporated herein by reference in their entireties.

[0064] The substrate can comprise a glass sheet having a first surface and an opposing second surface. The surfaces may, in certain embodiments, be planar or substantially planar, e.g., substantially flat and/or level. The substrate can also, in some embodiments, be curved about at least one radius of curvature, e.g., a three- dimensional substrate, such as a convex or concave substrate. The first and second surfaces may, in various embodiments, be parallel or substantially parallel. The substrate may further comprise at least one edge, for instance, at least two edges, at least three edges, or at least four edges. By way of a non-limiting example, the substrate may comprise a rectangular or square sheet having four edges, although other shapes and configurations are envisioned and are intended to fall within the scope of the disclosure. The laser cutting methods disclosed herein can also be used to create a variety of curved contours and resulting glass articles with curved, e.g., nonlinear edges.

[0065] The glass articles disclosed herein can be used to produce various products, such as insulated glass units (IGUs). For example, a glass article comprising at least a portion of a surface coated with an electrochromic layer can be sealed around the perimeter to a second glass sheet to produce an IGU. Because the glass article can be cut to size and/or shape after coating with the electrochromic layer, the manufacture of such IGUs may have improved flexibility and/or reduced cost.

[0066] It will be appreciated that the various disclosed embodiments may involve particular features, elements or steps that are described in connection with that particular embodiment. It will also be appreciated that a particular feature, element or step, although described in relation to one particular embodiment, may be interchanged or combined with alternate embodiments in various non-illustrated combinations or permutations.

[0067] It is also to be understood that, as used herein the terms "the," "a," or "an," mean "at least one," and should not be limited to "only one" unless explicitly indicated to the contrary. Thus, for example, reference to "a laser" includes examples having two or more such lasers unless the context clearly indicates otherwise. Likewise, a "plurality" is intended to denote "more than one." As such, a "plurality of defect lines" includes two or more such defect lines, such as three or more such defect lines, etc.

[0068] Ranges can be expressed herein as from "about" one particular value, and/or to "about" another particular value. When such a range is expressed, examples include from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent "about," it will be understood that the particular value forms another aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

[0069] The terms "substantial," "substantially," and variations thereof as used herein are intended to note that a described feature is equal or approximately equal to a value or description. For example, a "substantially planar" surface is intended to denote a surface that is planar or approximately planar.

[0070] Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not actually recite an order to be followed by its steps or it is not otherwise specifically stated in the claims or descriptions that the steps are to be limited to a specific order, it is no way intended that any particular order be inferred.

[0071] While various features, elements or steps of particular embodiments may be disclosed using the transitional phrase "comprising," it is to be understood that alternative embodiments, including those that may be described using the transitional phrases "consisting" or "consisting essentially of," are implied. Thus, for example, implied alternative embodiments to an article that comprises A+B+C include embodiments where an article consists of A+B+C and embodiments where an article consists essentially of A+B+C.

[0072] It will be apparent to those skilled in the art that various modifications and variations can be made to the present disclosure without departing from the spirit and scope of the disclosure. Since modifications combinations, sub-combinations and variations of the disclosed embodiments incorporating the spirit and substance of the disclosure may occur to persons skilled in the art, the disclosure should be construed to include everything within the scope of the appended claims and their equivalents.