Transparent article with low-roughness glass-ceramic substrate and optical film structure, and methods of making the same

Abstract

A transparent article is described herein that includes: a glass-ceramic substrate; and an optical film structure having an outer surface and a thickness of about 200 nm to 5000 nm, disposed on the first primary surface of the substrate. The optical film structure comprises a scratch-resistant layer, at least one low refractive index (RI) layer, at least one medium RI layer, and at least one high RI layer. The optical film structure further comprises an outer and inner structure, the scratch-resistant layer disposed between the outer and inner structures, the inner structure disposed on the first primary surface, the outer structure comprising a plurality of alternating high and medium RI layers, and the inner structure comprising a plurality of alternating high RI layers and low RI layers. In addition, the first primary surface of the glass-ceramic substrate comprises a surface roughness (Ra) of less than 1.5 nm.

Description

TRANSPARENT ARTICLE WITH LOW-ROUGHNESS GLASSCERAMIC SUBSTRATE AND OPTICAL FILM STRUCTURE, AND METHODS OF MAKING THE SAMECLAIM OF PRIORITY

[0001] This application claims the benefit of priority under 35 U.S.C. § 119(e) of U.S. Provisional Patent Application No. 63 / 676,566, filed on July 29, 2024, and U.S. Provisional Patent Application No. 63 / 753,733, filed on February 04, 2025.FIELD

[0002] This disclosure relates to transparent articles (and methods of making them) for protection of optical articles and display devices, and particularly to transparent articles having a glass-ceramic substrate with an optical film structure disposed thereon with an outer structure with one or more medium index layers that exhibit various optical and mechanical performance attributes including, but not limited to, low variation in reflectance in the visible spectrum, low overall reflectance, high shallow hardness, low glare, high visible and infrared transmittance, low reflected color, color uniformity, and minimized overall thickness.BACKGROUND

[0003] Cover articles with substrates are often used to protect critical devices and components within electronic products and systems, such as mobile devices, smart phones, computer tablets, hand-held devices, vehicular displays and other electronic devices with displays, cameras, light sources and / or sensors. These cover articles can also be employed in architectural articles, transportation articles (e.g., articles used in automotive applications, trains, aircraft, sea craft, etc.), appliance articles, or any article that requires some transparency, scratch resistance, abrasion resistance, or a combination thereof.

[0004] These applications that employ cover articles often demand a combination of mechanical and environmental durability, breakage resistance, damage resistance, scratch resistance and strong optical performance characteristics. For example, the cover articles may be required to exhibit high light transmittance, low reflectance and / or low transmitted color in the visible spectrum. In some applications, the cover articles are required to coverand protect display devices, cameras, sensors and / or light sources. Further, the use of glassceramic substrates in these cover articles can provide advantages in article-level mechanical performance as compared to cover articles employing glass substrates.

[0005] Nevertheless, conventional cover articles employing glass-ceramic substrates and optical fdm structures can suffer from reduced optical performance. In particular, the inclusion of optical fdm structures on glass-ceramic substrates has provided advantages in terms of optical performance (e.g., high visible and infrared transmittance) and certain mechanical properties (e.g., scratch resistance); however, conventional combinations of these substrates and optical fdm structures (e.g., as optimized for improved scratch resistance with high modulus and / or hardness) have resulted in undesirable variations in reflectance levels observed in the visible spectrum (e.g., an iridescent appearance). Notably, it is believed that uncontrolled surface roughness, porosity and / or other morphological features at the interface between the glass-ceramic substrate and the optical fdm structure can disadvantageous^ contribute to these undesirable optical effects.

[0006] Accordingly, there is a need for improved cover articles for protection of optical articles and devices, particularly transparent articles that exhibit low variation in reflectance in the visible spectrum, low overall reflectance, high shallow hardness, low glare, high visible and infrared transmittance, low reflected color, color uniformity, and minimized overall thickness. There is also a need for methods of making such articles and devices.SUMMARY

[0007] According to an aspect of the disclosure, a transparent article is provided that includes: a glass-ceramic substrate comprising a first primary surface and a second primary surface, the primary surfaces opposing one another, the first primary surface of the glassceramic substrate comprises a surface roughness (Ra) of less than 1.5 nm; and the glassceramic substrate further comprises a porosity of less than 25% within a portion of the substrate from the first primary surface to a depth of 100 nm.

[0008] According to an aspect of the disclosure, a transparent article is provided that includes: a glass-ceramic substrate comprising a first primary surface and a second primary surface, the primary surfaces opposing one another; and an optical film structure having an outer surface and a physical thickness of from about 200 nm to 5000 nm, the optical filmstructure disposed on the first primary surface. The optical film structure comprises a scratch-resistant layer, at least one low refractive index (RI) layer, at least one medium RI layer, and at least one high RI layer. The optical film structure further comprises an outer structure and an inner structure, the scratch-resistant layer disposed between the outer and inner structures, the inner structure disposed on the first primary surface, the outer structure comprising a plurality of alternating high and medium RI layers, and the inner structure comprises a plurality of alternating high RI layers and low RI layers. Further, each medium RI layer comprises a refractive index from 1.55 to 1.9, each of the high RI layers comprises a refractive index of greater than 1.80, and each of the low RI layers comprises a refractive index from 1.35 to 1.7. In addition, the first primary surface of the glass-ceramic substrate comprises a surface roughness (Ra) of less than 1.5 nm.

[0009] According to an aspect of the disclosure, a transparent article is provided that includes: a glass-ceramic substrate comprising a first primary surface and a second primary surface, the primary surfaces opposing one another; and an optical film structure having an outer surface and a physical thickness of from about 200 nm to 5000 nm, the optical film structure disposed on the first primary surface. The optical film structure comprises a scratch-resistant layer, at least one low refractive index (RI) layer, at least one medium RI layer, and at least one high RI layer. The optical film structure further comprises an outer structure and an inner structure, the scratch-resistant layer disposed between the outer and inner structures, the inner structure disposed on the first primary surface, the outer structure comprising a plurality of alternating high and medium RI layers, and the inner structure comprises a plurality of alternating high RI layers and low RI layers. Further, each medium RI layer comprises a refractive index from 1.55 to 1.9, each of the high RI layers comprises a refractive index of greater than 1.80, and each of the low RI layers comprises a refractive index from 1.35 to 1.7. In addition, the article exhibits a variation of less than 1% in a first- surface reflectance, as measured from 0° to 10° incidence within a range from 450 nm to 700 nm, the variation defined as the difference between the maximum and minimum first-surface reflectance measured in any 100 nm increment within the range.

[0010] According to an aspect of the disclosure, a method of making a transparent article is provided that includes: providing a glass-ceramic substrate, the glass-ceramic substrate comprising a first primary surface and a second primary surface, the primary surfacesopposing one another; polishing the first primary surface to a surface roughness (Ra) of less than 1.5 nm; immersing the glass-ceramic substrate in a molten salt bath to form a compressive stress region in the substrate from each of the primary surfaces to a depth within the glass-ceramic substrate; polishing the first primary surface of the glass-ceramic substrate having the compressive stress region to a surface roughness (Ra) of less than 1.5 nm and a material removal to a depth of 0.1 to 10 pm from the first primary surface; washing the glassceramic substrate in an aqueous bath after the polishing steps; and disposing an optical film structure on the first primary surface of the glass-ceramic substrate after the washing step to define a transparent article comprising the glass-ceramic substrate and the optical film structure, the optical film structure having an outer surface and a physical thickness of from about 200 nm to 5000 nm. The optical film structure comprises a scratch-resistant layer, at least one low refractive index (RI) layer, at least one medium RI layer, and at least one high RI layer. The optical film structure further comprises an outer structure and an inner structure, the scratch-resistant layer disposed between the outer and inner structures, the inner structure disposed on the first primary surface, the outer structure comprising a plurality of alternating high and medium RI layers, and the inner structure comprises a plurality of alternating high RI layers and low RI layers. Each medium RI layer comprises a refractive index from 1.55 to 1.9, each of the high RI layers comprises a refractive index of greater than 1.80, and each of the low RI layers comprises a refractive index from 1.35 to 1.7. Further, the first primary surface of the glass-ceramic substrate comprises a surface roughness (Ra) of less than 1.5 nm after the washing step.

[0011] According to an aspect of the disclosure, a transparent article is provided that includes: a glass-ceramic substrate comprising a first primary surface and a second primary surface, the primary surfaces opposing one another, and an optical film structure having an outer surface and a physical thickness of from about 200 nm to 5000 nm, the optical film structure disposed on the first primary surface, wherein the optical film structure comprises a scratch-resistant layer, and a plurality of alternating low refractive index (RI) layers, and high RI layers, each of the high RI layers comprises a refractive index of greater than 1.80, and each of the low RI layers comprises a refractive index from 1.35 to 1.7, and further wherein the first primary surface of the glass-ceramic substrate comprises a surface roughness (Ra) of less than 1.5 nm.

[0012] According to an aspect of the disclosure, a transparent article is provided that includes: a glass-ceramic substrate comprising a first primary surface and a second primary surface, the primary surfaces opposing one another; and an optical film structure having an outer surface and a physical thickness of from about 200 nm to 5000 nm, the optical film structure disposed on the first primary surface. The optical film structure comprises a scratch-resistant layer, at least one low refractive index (RI) layer, at least one medium RI layer, and at least one high RI layer. The optical film structure further comprises an outer structure and an inner structure, the scratch-resistant layer disposed between the outer and inner structures, the inner structure disposed on the first primary surface, the outer structure comprising a capping layer and a plurality of alternating high and medium RI layers, and the inner structure comprises a plurality of alternating medium RI layers and low RI layers. Further, each medium RI layer comprises a refractive index from 1.55 to 1.9, each of the high RI layers comprises a refractive index of greater than 1.80, and each of the low RI layers comprises a refractive index from 1.35 to 1.7. In addition, the first primary surface of the glass-ceramic substrate comprises a surface roughness (Ra) of less than 1.5 nm.

[0013] According to other aspects of the disclosure, a display device is provided that includes one or more of the foregoing transparent articles, with each article serving as a protective cover for the display device.

[0014] Additional features and advantages 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 embodiments as described herein, including the detailed description which follows, the claims, as well as the appended drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0015] It is to be understood that both the foregoing general description and the following detailed description are merely exemplary, and are intended to provide an overview or framework to understanding the nature and character of the claims. The accompanying drawings are included to provide a further understanding, and are incorporated in and constitute a part of this specification. The drawings illustrate one or more embodiments, and together with the description serve to explain principles and operation of the various embodiments, wherein:

[0016] FIG. 1 is a cross-sectional side view of a transparent article (e.g., for a display device), according to one or more embodiments of the disclosure;

[0017] FIG. 1A is a cross-sectional side view of a transparent article (e.g., for a display device), according to one or more embodiments of the disclosure;

[0018] FIG. IB is a cross-sectional side view of a transparent article (e.g., for a display device), according to one or more embodiments of the disclosure;

[0019] FIG. 2A is a plan view of an exemplary electronic device incorporating any of the transparent articles disclosed herein;

[0020] FIG. 2B is a perspective view of the exemplary electronic device of FIG. 2A;

[0021] FIG. 2C is a perspective view of an alternative embodiment of the electronic device of FIG. 2A with a non-planar substrate having curved or faceted edges, according to one or more embodiments of the disclosure;

[0022] FIG. 3A (PRIOR ART) is a pair of scanning electron microscope (SEM) micrographs (100 kX and 50 kX, respectively) of a cover article, specifically, a primary surface of a glass-ceramic substrate and an optical film structure disposed on the substrate;

[0023] FIG. 3B (PRIOR ART) is an SEM micrograph of the cover article of FIG. 3A (magnification not shown, higher magnification than FIG. 3A);

[0024] FIG. 3C (PRIOR ART) is an atomic force microscopy (AFM) three-dimensional image and two-dimensional AFM image of the primary surface of a glass-ceramic substrate of a cover article substantially similar to the cover article of FIG. 3 A;

[0025] FIGS. 4A and 4B, respectively, are AFM images of a primary surface of glassceramic substrates, as processed according to a comparative substrate processing method and a substrate processing method, according to one or more embodiments of the disclosure;

[0026] FIG. 4C is an AFM image of a primary surface of a glass-ceramic substrate, as processed according to an aspect of a substrate processing method, according to one or more embodiments of the disclosure;

[0027] FIG. 4D is an AFM image of a primary surface of a glass-ceramic substrate, as processed according to an aspect of a comparative substrate processing method;

[0028] FIG. 4E are AFM images of two locations on a primary surface of a pair of glassceramic substrates, as processed according to a substrate processing method, according to one or more embodiments of the disclosure;

[0029] FIGS. 5A and 5B are plots of first-surface reflectance and two-surface transmittance vs. wavelength, as measured at a near-normal incident angle of 8° and 0°, respectively, for a transparent article, according to one or more embodiments of the disclosure;

[0030] FIG. 5C is a plot of single-sided, reflected color, as measured at incident angles from 0° to 90°, for the transparent article of FIGS. 5 A and 5B;

[0031] FIG. 5D is a bar chart depicting average first-surface reflectance of the transparent article of FIGS. 5A and 5B, as measured at a near-normal incident angle of 8°, vs. various levels of material from the outermost surface of the optical film structure, according to one or more embodiments of the disclosure;

[0032] FIG. 5E is a plot of first-surface reflectance vs. wavelength, as measured at a nearnormal incident angle of 8°, for three comparative transparent articles and an inventive transparent article, according to one or more embodiments of the disclosure;

[0033] FIGS. 6A and 6B are plots of first-surface reflectance and two-surface transmittance vs. wavelength, as measured at a near-normal incident angle of 8° and 0°, respectively, for a transparent article, according to one or more embodiments of the disclosure;

[0034] FIG. 6C is a plot of single-sided, reflected color, as measured at incident angles from 0° to 90°, for the transparent article of FIGS. 6A and 6B;

[0035] FIG. 6D is a bar chart depicting average first-surface reflectance of the transparent article of FIGS. 6A and 6B, as measured at a near-normal incident angle of 8°, vs. various levels of material from the outermost surface of the optical film structure, according to one or more embodiments of the disclosure;

[0036] FIGS. 7A and 7B are plots of first-surface reflectance and two-surface transmittance vs. wavelength, as measured at a near-normal incident angle of 8° and 0°, respectively, for a transparent article, according to one or more embodiments of the disclosure;

[0037] FIG. 7C is a plot of single-sided, reflected color, as measured at incident angles from 0° to 90°, for the transparent article of FIGS. 7A and 7B;

[0038] FIG. 7D is a bar chart depicting average first-surface reflectance of the transparent article of FIGS. 7A and 7B, as measured at a near-normal incident angle of 8°, vs. variouslevels of material from the outermost surface of the optical film structure, according to one or more embodiments of the disclosure;

[0039] FIGS. 8 A and 8B are plots of two-surface reflectance and transmittance as measured at a near-normal incident angle of 8° and 0°, respectively, for a transparent article, according to one or more embodiments of the disclosure;

[0040] FIGS. 9A and 9B are plots of first-surface reflectance and two-surface transmittance vs. wavelength, as measured at a near-normal incident angle of 8° and 0°, respectively, for a transparent article, according to one or more embodiments of the disclosure;

[0041] FIG. 9C is a plot of single-sided, reflected color, as measured at incident angles from 0° to 90°, for the transparent article of FIGS. 9A and 9B;

[0042] FIGS. 9D and 9E are plots of first-surface reflectance and two-surface transmittance vs. wavelength, as measured at a near-normal incident angle of 8° and 0°, respectively, for a transparent article, according to one or more embodiments of the disclosure;

[0043] FIG. 9F is a plot of single-sided, reflected color, as measured at incident angles from 0° to 90°, for the transparent article of FIGS. 9D and 9E;

[0044] FIGS. 9G and 9H are plots of first-surface reflectance and two-surface transmittance vs. wavelength, as measured at a near-normal incident angle of 8° and 0°, respectively, for a transparent article, according to one or more embodiments of the disclosure;

[0045] FIG. 91 is a plot of single-sided, reflected color, as measured at incident angles from 0° to 90°, for the transparent article of FIGS. 9G and 9H;

[0046] FIG. 10A is a modeled plot of a compressive stress profile from an ion-exchange process vs. substrate thickness for a glass-ceramic substrate, according to one or more embodiments of the disclosure;

[0047] FIG. 10B is a modeled plot of the variation in compressive stress from an ionexchange process vs. substrate thickness for the glass-ceramic substrate of FIG. 10A; and

[0048] FIG. 10C is a modeled plot of approximate stress profiles for the glass-ceramic substrate of FIGS. 10A and 10B vs. substrate thickness.DETAILED DESCRIPTION

[0049] In the following detailed description, for purposes of explanation and not limitation, example embodiments disclosing specific details are set forth to provide a thorough understanding of various principles of the present disclosure. However, it will be apparent to one having ordinary skill in the art, having had the benefit of the present disclosure, that the present disclosure may be practiced in other embodiments that depart from the specific details disclosed herein. Moreover, descriptions of well-known devices, methods and materials may be omitted so as not to obscure the description of various principles of the present disclosure. Finally, wherever applicable, like reference numerals refer to like elements.

[0050] Ranges can be expressed herein as from “about” one particular value, and / or to “about” another particular value. When such a range is expressed, another embodiment includes 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 embodiment. 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.

[0051] Directional terms as used herein - for example “up,” “down,” “right,” “left,” “front,” “back,” “top,” “bottom” - are made only with reference to the figures as drawn and are not intended to imply absolute orientation.

[0052] 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 in no way intended that an order be inferred, in any respect. This holds for any possible non-express basis for interpretation, including: matters of logic with respect to arrangement of steps or operational flow; plain meaning derived from grammatical organization or punctuation; and the number or type of embodiments described in the specification.

[0053] 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 having two or more such components, unless the context clearly indicates otherwise.

[0054] As used herein, the term “dispose” includes coating, depositing, and / or forming a material onto a surface using any known or to be developed method in the art. The disposed material may constitute a layer, as defined herein. As used herein, the phrase “disposed on” includes forming a material onto a surface such that the material is in direct contact with the surface and embodiments where the material is formed on a surface with one or more intervening material(s) disposed between material and the surface. The intervening material(s) may constitute a layer, as defined herein.

[0055] As used herein, the terms “low RI layer”, “medium RI layer” and “high RI layer” refer to the relative values of the refractive index (“RI”) of layers of an optical film structure of a transparent article according to the disclosure. Hence, the RI of the low RI layer < the RI of the medium RI layer < the RI of the high RI layer, unless otherwise expressly noted in this disclosure. Accordingly, low RI layers have refractive index values that are less than the refractive index values of medium and high RI layers. Further, as used herein, “low RI layer” and “low index layer” are interchangeable with the same meaning. Likewise, “medium RI layer” and “medium index layer” are interchangeable with the same meaning. Similarly, “high RI layer” and “high index layer” are interchangeable with the same meaning.

[0056] As used herein the term “glass-ceramic substrate” is not limited to glass-ceramic substrates. Rather, the term “glass-ceramic substrate” refers to a group of substrates that are inclusive of glass-ceramic substrates, ceramic substrates, and strengthened glass-ceramic substrates.

[0057] As used herein, the term “strengthened substrate” refers to a substrate employed in a transparent article of the disclosure that has been chemically strengthened, for example through ion-exchange of larger ions for smaller ions in the surface of the substrate. However, other strengthening methods known in the art, such as thermal tempering, or utilizing a mismatch of the coefficient of thermal expansion between portions of the substrate to create compressive stress and central tension regions, may be utilized to form strengthened substrates.

[0058] As used herein, the “Berkovich Indenter Hardness Test” and “Berkovich HardnessTest” are used interchangeably to refer to a test for measuring the hardness of a material on asurface thereof by indenting the surface with a diamond Berkovich indenter. The Berkovich Indenter Hardness Test includes indenting the outermost surface (e.g., an exposed surface) of a single optical fdm structure or the outer optical fdm structure of a transparent article of the disclosure with the diamond Berkovich indenter to form an indent to an indentation depth in the range from about 50 nm to about 1000 nm (or the entire thickness of the outer or inner optical fdm structure, whichever is less) and measuring the maximum hardness from this indentation along the entire indentation depth range or a segment of this indentation depth (e.g., in the range from about 100 nm to about 600 nm), generally using the methods set forth in Oliver, W.C.; Pharr, G. M. An improved technique for determining hardness and elastic modulus using load and displacement sensing indentation experiments. J. Mater. Res., Vol. 7, No. 6, 1992, 1564-1583; and Oliver, W.C.; Pharr, G.M. Measurement of Hardness and Elastic Modulus by Instrument Indentation: Advances in Understanding and Refinements to Methodology. J. Mater. Res., Vol. 19, No. 1, 2004, 3-20. As used herein, each of “hardness” and “maximum hardness” interchangeably refers to a maximum hardness as measured along a range of indentation depths, and not an average hardness.

[0059] As used herein, the term “transmittance” is defined as the percentage of incident optical power within a given wavelength range transmitted through a material (e.g., the article, the substrate or the optical film or portions thereof). The term “reflectance” is similarly defined as the percentage of incident optical power within a given wavelength range that is reflected from a material (e.g., the article, the substrate, or the optical film or portions thereof). Transmittance and reflectance are measured using a specific linewidth. As used herein, an “average transmittance” refers to the average amount of incident optical power transmitted through a material over a defined wavelength regime. As used herein, an “average reflectance” refers to the average amount of incident optical power reflected by the material.

[0060] As used herein, “photopic reflectance” mimics the response of the human eye by weighting the reflectance or transmittance, respectively, versus wavelength spectrum according to the human eye’s sensitivity. Photopic reflectance may also be defined as the luminance, or tristimulus Y value of reflected light, according to known conventions such as CIE color space conventions. The “average photopic reflectance”, as used herein, for a wavelength range from 380 nm to 720 nm is defined in the below equation as the spectralreflectance, R(X) multiplied by the illuminant spectrum, I(X) and the CIE’s color matching function related to the eye’s spectral response:In addition, “average reflectance” can be determined over the visible spectrum, or over other wavelength ranges, according to measurement principles understood by those skilled in the field of the disclosure, e.g., in the infrared spectrum from 840 nm to 950 nm, etc. Unless otherwise noted, all reflectance values reported or otherwise referenced in this disclosure are associated with testing through both primary surfaces of the substrate and optical film structure(s) of the transparent articles of the disclosure, e.g., a “two-surface” average photopic reflectance. In cases where “one-surface” or “first-surface” reflectance is specified, the reflectance from the rear surface of the article is eliminated through optical bonding to a light absorber, allowing the reflectance of only the first surface to be measured.

[0061] The usability of a transparent article in an electronic device (e.g., as a protective cover) can be related to the total amount of reflectance in the article. Photopic reflectance is particularly important for display devices that employ visible light. Lower reflectance in a cover transparent article over a lens and / or a display associated with the device can reduce multiple -bounce reflections in the device that can generate ‘ghost images’. Thus, reflectance has an important relationship to image quality associated with the device, particularly its display and any of its other optical components (e.g., a lens of a camera). Low-reflectance displays also enable better display readability, reduced eye strain, and faster user response time (e.g., in an automotive display, where display readability can also correlate to driver safety). Low-reflectance displays can also allow for reduced display energy consumption and increased device battery life, since the display brightness can be reduced for low-reflectance displays compared to standard displays, while still maintaining the targeted level of display readability in bright ambient environments.

[0062] As used herein, “photopic transmittance” is defined in the below equation as the spectral transmittance, T(X) multiplied by the illuminant spectrum, I(X) and the CIE’s color matching functionrelated to the eye’s spectral response:In addition, “average transmittance” or “average photopic transmittance” can be determined over the visible spectrum or other wavelength ranges, according to measurement principles understood by those skilled in the field of the disclosure, e.g., in the infrared spectrum from 840 nm to 950 nm, etc. Unless otherwise noted, all transmittance values reported or otherwise referenced in this disclosure and claims are associated with testing through both primary surfaces of the substrate and the optical film structure (e.g., the glass-ceramic substrate 110, primary surfaces 112, 114, and optical film structure 120 as shown in FIG. 1 and described below) of the transparent articles, e.g., a “two-surface” average photopic transmittance.

[0063] As used herein, “transmitted color” and “reflected color” refer to the color transmitted or reflected through the transparent articles of the disclosure with regard to color in the CIE L*, a*, b* colorimetry system under a D65 illuminant. More specifically, the “color shift” (i.e., as measured in transmission or reflectance) is given by ^l(a*2+ b*2), as these color coordinates are measured through transmission or reflectance of a D65 illuminant through the primary surfaces of the substrate of the transparent article (e.g., the glass-ceramic substrate 110, primary surfaces 112, 114, and optical film structure 120 as shown in FIG. 1 and described below) over an incident angle range, e.g., from 0 degrees to 10 degrees.

[0064] As also used herein, an “optical film structure thickness scaling factor” and “thickness scaling factor” are interchangeable and generally refer to expected differences in the thickness of the optical film structures of the disclosure that can occur from vapor deposition of the optical film structure on a non-planar substrate or non-planar portions of a substrate. These optical film structure thickness differences as a function of methods employed to deposit these structures on substrates are detailed in following co-assigned: (1) U.S. Patent No. 10,802,179 B2; (2) U.S. Patent No. 11,500,130 B2; and (3) U.S. Patent Publication No. 2023 / 0273345, the salient portions of which are related to thickness scaling factors and similar concepts are hereby incorporated by reference in this disclosure. In turn, these variances in the thickness of the optical film structure may result in non-uniformity of transmitted and / or reflected color exhibited by the transparent articles of the disclosure possessing such optical film structures. As such, transmitted and reflected color values arereported in this disclosure for various thickness scaling factors such that “100%” corresponds to color measurements on an optical film structure on a planar surface of the substrate or at the maximum thickness of the optical film structure on a surface of the substrate, “90%” corresponds to the color measurements on an optical film structure on a non-planar surface having 90% of the thickness of the portion of the optical film structure on an adjacent planar surface or the portion of the optical film structure on a surface of the substrate having a maximum thickness, and so on.

[0065] Generally, the disclosure is directed to transparent articles (and methods of making them) that employ optical film structures over glass-ceramic substrates, including strengthened glass-ceramic substrates, with a controlled level of surface roughness, porosity and morphological features. These transparent articles can include a high toughness, high modulus glass-ceramic substrate that is optically transparent, with a high-hardness optical coating having controlled transmittance and color. In view of this combination of substrate and optical film structure, the transparent article can exhibit a high shallow hardness, while also exhibiting transparency, low reflectance, high visible and IR transmittance, and low color. Further, the transparent articles of the disclosure can exhibit a low degree of reflectance variation in the visible spectrum and, accordingly, limited or no iridescence in reflectance.

[0066] Further, the transparent articles of the disclosure exhibit an advantageous combination of mechanical and optical properties over known transparent articles, including one or more of the following: an average photopic reflectance of < 1%, an average infrared (940 nm) reflectance of < 3.5%, a maximum hardness of greater than 12 GPa, and an optical film structure with outer structure having a total physical thickness from 400-800 nm and / or at least one medium RI layer with a refractive index from 1.55-1.9.

[0067] In aspects of these transparent articles, the optical film structures are configured such that the articles that employ them exhibit a hardness of at least about 8 GPa, 10 GPa, 12 GPa, at least about 14 GPa, or even at least about 16 GPa, at a Barkovich nanoindentation depth of about 125 nm from the outer surface of the optical film structure. The optical film structure may comprise a multilayer optical interference film composed of SiC>2, SiOx, SiOxNy, SiNy, and / or SisN4 layers, which comprises a scratch-resistant layer (e.g., as embedded within the structure). According to some implementations, an outer structure ofthe optical film structure above the scratch-resistant layer can be configured with at least one medium RI layer (e.g., SiOxNy) in contact with one of the high RI layers and the scratchresistant layer (e.g., SiOxNyor SiNy) and / or a sum of the physical thicknesses of all of the low RI layers (e.g., SiCh or SiOxNy) in the outer structure limited to about 75 run or more. Some or all of these structural characteristics can enable or otherwise significantly influence the achievement of these shallow high hardness levels.

[0068] The transparent articles of the disclosure can be employed for protection and / or covers of displays, camera lenses, sensors and / or light source components within or otherwise part of electronic devices, along with protection of other components (e.g., buttons, speakers, microphones, etc.). These transparent articles with a protective function employ an optical film structure disposed on a substrate such that the article exhibits a combination of high shallow hardness and desirable optical properties. Advantageously, these shallow high hardness levels are exhibited by the transparent articles of the disclosure without an appreciable loss in optical properties, e.g., low reflectance in the visible and IR spectra and low reflected color.

[0069] As also outlined in the disclosure, the foregoing, advantageous article-level high shallow hardness levels can be achieved through the control of the composition and / or arrangement of the optical film structures employed in the transparent articles. Notably, these hardness levels can be achieved by the articles of the disclosure while maintaining desired optical properties. In terms of optical properties, the transparent articles of the disclosure can exhibit an average first-surface photopic reflectance of less than 3%, 2.5%, 2%, 1.75%, 1.5%, 1.25%, 1%, or even 0.9%, and a first-surface reflectance at a wavelength of 940 nm of less than 5%, 4.5%, 4%, 3.5%, 3.0%, 2.5%, 2%, or even 1.7%, all as measured at a near-normal angle of incidence (0-10°).

[0070] The transparent articles with a protective function can also employ an optical film structure disposed on a glass-ceramic substrate such that the article exhibits a combination of high hardness, high damage resistance and desirable optical properties, including high photopic transmittance and low transmitted color. The optical film structure can include a scratch-resistant layer, at any of various locations within the structure. Further, the outer structure of the optical film structures of these articles can include a plurality of alternatinghigh and low refractive index layers, with each high index layer and a scratch resistant layer comprising nitride or an oxynitride and each low index layer comprising an oxide.

[0071] With regard to mechanical properties, embodiments of the transparent articles of the disclosure can exhibit a maximum hardness of 12 GPa or greater or 14 GPa or greater (or even greater than 16 GPa in some instances), as measured by a Berkovich Hardness Test over an indentation depth range from 100 nm to about 500 nm in the optical fdm structure. The glass-ceramic substrates employed in these articles can have an elastic modulus of greater than 85 GPa, or greater than 95 GPa in some instances. These glass-ceramic substrates also can exhibit a fracture toughness of greater than 0.8 MPa-^m. or greater than 1 MPa-^m in some instances.

[0072] According to some embodiments of the transparent articles of the disclosure, advantageous article-level failure stress levels can be achieved through the control of the composition, arrangement and / or processing of the optical fdm structures employed in the transparent articles. Notably, the composition, arrangement and / or processing of the optical fdm structures can be adjusted to obtain residual compressive stress levels of at least 700 MPa (e.g., from 700 to 1100 MPa) and an elastic modulus of at least 140 GPa (e.g., from 140 to 170 GPa, from 140 to 180 GPa, from 140 to 190 GPa, or from 140 to 200 GPa). These optical fdm structure mechanical properties correlate to average failure stress levels of 500 MPa or greater, 600 MPa or greater, or even 700 MPa or greater, in the transparent articles employing these optical fdm structures, as measured in a Ring -on-Ring (ROR) test with the outer surface of the optical fdm structure of the article placed in tension.

[0073] As used herein, a “Ring-on-Ring Test” refers to a test conducted with failure load being correlated to stress in the glass of a glass wafer being tested, and finite element analysis (FEA) is used to convert load to stress, to present a more accurate representation of Ring-on- Ring Test behavior than beam theory. An equibiaxial flexure test (ROR Test) can be conducted with a displacement rate of 1.2 mm / min at 23°C and 50% room humidity with a load ring diameter as 25.4 mm and support ring diameter of 12.7 mm, as described in ASTM C 1499-23. Failure load measured in the equibiaxial flexure test (ROR Test) correlates to stress in the substrate of the transparent article being tested. However, without being bound by theory, it is believed that the use of a numerical model such as finite element model to convert failure load to failure stress presents a more accurate representation of an equibiaxialflexure test (ROR Test) than simply assuming beam (linear) bending theory that further disregards the geometric non-linearity to evaluate stress, particularly for thin articles, e.g. with thickness less than 1.0mm or less than 0.6mm. ASTM C1499-23 stipulates the use of an equibiaxial flexure test (ROR Test) only up to the regime of linear bending behavior, disregarding the geometric non-linearity. Consequently, a finite element (FE) model was built using commercially available software, ABAQUS, in standard explicit mode. The FE model of the equibixial flexure test (ROR Test) was setup as axisymmetric including geometric nonlinearity while neglecting material non-linearity. The shell planar elements were chosen with a solid homogeneous section. The contact between the material being tested and the rings were defined as frictionless while the normal contact was defined as hard contact. The elastic properties of the material being tested and the rings used were also defined. As the displacement is applied to the load ring to simulate the test up to a maximum value, the reaction loads on the ring along with the maximum radial stress on the tension side surface of the plate / sheet / wafer being tested is in the vicinity directly below the load ring is tabulated. These converted failure stress values align with results (stress) that may be measured through other physical experiments conducted on the samples using a strain gauge or using other optical techniques such as digital image correlation (DIC). Further, the finite element analysis and correction may be validated using strain gauge measurements (or other empirical measurements). Alternatively strain gauge measurements may directly be used for stress and strain data (e.g., failure strain) if such numerical modeling does not align with empirical results. Further details of the Ring-on-Ring test and finite element analysis methods are described in U.S. Provisional Patent Application No. 63 / 730,114, filed December 10, 2024, the salient contents of which is hereby incorporated by reference in this disclosure in its entirety.

[0074] Referring to FIG. 1, a transparent article 100 according to one or more embodiments may include a glass-ceramic substrate 110, and an optical film structure 120 defining an outer surface 120a and an inner surface 120b disposed on the substrate 110. The substrate 110 includes opposing primary surfaces 112, 114 and opposing secondary surfaces 116, 118. The optical film structure 120 is shown in FIG. 1, with its inner surface 120b disposed on a first opposing primary surface 112 and no optical film structures are shown as being disposed on the second opposing primary surface 114. In some embodiments,however, one or more of the optical film structures 120 can be disposed on the second opposing primary surface 114 and / or on one or both of the opposing secondary surfaces 116, 118.

[0075] The optical film structure 120 includes at least one layer of material. As used herein, the term “layer” may include a single layer or may include one or more sub-layers. Such sub-layers may be in direct contact with one another. The sub-layers may be formed from the same material or two or more different materials. In one or more alternative embodiments, such sub-layers may have intervening layers of different materials disposed therebetween. In one or more embodiments, a layer may include one or more contiguous and uninterrupted layers and / or one or more discontinuous and interrupted layers (i.e., a layer having different materials formed adjacent to one another). A layer or sub-layer may be formed by any known method in the art, including discrete deposition or continuous deposition processes. In one or more embodiments, the layer may be formed using only continuous deposition processes, or, alternatively, only discrete deposition processes.

[0076] In one or more embodiments, a single layer or multiple layers of the optical film structure 120 may be deposited onto a glass-ceramic substrate 110 by a vacuum deposition technique such as, for example, chemical vapor deposition (e.g., plasma enhanced chemical vapor deposition (PECVD), low-pressure chemical vapor deposition, atmospheric pressure chemical vapor deposition, and plasma-enhanced atmospheric pressure chemical vapor deposition), physical vapor deposition (e.g., reactive or nonreactive sputtering or laser ablation), thermal or e-beam evaporation and / or atomic layer deposition. Liquid-based methods may also be used such as spraying, dipping, spin coating, or slot coating (e.g., using sol-gel materials). Generally, vapor deposition techniques may include a variety of vacuum deposition methods which can be used to produce thin films. For example, physical vapor deposition uses a physical process (such as heating or sputtering) to produce a vapor of material, which is then deposited on the object which is coated. Preferred methods of fabricating the optical film structure 120 can include reactive sputtering, metal-mode reactive sputtering and PECVD processes.

[0077] The optical film structure 120 may have a physical thickness of from about 100 nm to about 5 microns. For example, the optical film structure 120 may have a thickness greater than or equal to about 200 nm, 300 nm, 325 nm, 350 nm, 375 nm, 400 nm, 500 nm, 600 nm,700 nm, 800 nm, 900 nm, 1 micron, 2 microns, 3 microns, 4 microns, and less than or equal to about 5 microns. In some implementations of the transparent articles 100 depicted in FIG. 1, the optical fdm structure 120 has a physical thickness from 200 nm to 5000 nm, 500 nm to 2000 nm, or 1500 nm to 2000 nm, and all sub-ranges and thickness values between the foregoing ranges.

[0078] In some embodiments, as depicted for example in FIG. 1, the optical film structure 120 is divided into an outer structure 130a and an inner structure 130b, with a scratchresistant layer 150 (as detailed further below) disposed between the structures 130a and 130b. In these embodiments, the outer and inner optical film structures 130a and 130b may have the same thicknesses or different thicknesses, and each comprises one or more layers.

[0079] Referring again to the transparent article 100 depicted in FIG. 1, the optical film structure 120 includes one or more scratch-resistant layer(s) 150. For example, the transparent article 100 depicted in FIG. 1 includes an optical film structure 120 with a scratch-resistant layer 150 disposed over a primary surface 112 of the glass-ceramic substrate 110. According to one embodiment, the scratch-resistant layer 150 may comprise one or more materials chosen from SiuAlvOxNy, Ta2Os, Nb20s, AIN, A1NX, SiAlxNy, AlNx / SiAlxNy, SisN-i. A10xNy, SiOxNy, SiNy, SiNx:Hy, HfCh. TiCh. ZrCh. Y2O3, AI2O3, MoOs, diamond-like carbon, or combinations thereof. Exemplary materials used in the scratch-resistant layer 150 may include an inorganic carbide, nitride, oxide, diamond-like material, or combinations thereof. Examples of suitable materials for the scratch-resistant layer 150 include metal oxides, metal nitrides, metal oxynitride, metal carbides, metal oxycarbides, and / or combinations thereof. Exemplary metals include B, Al, Si, Ti, V, Cr, Y, Zr, Nb, Mo, Sn, Hf, Ta and W. Specific examples of materials that may be utilized in the scratch-resistant layer 150 may include AI2O3, AIN, A10xNy, SisN4, SiOxNy, SiuAlvOxNy, diamond, diamond-like carbon, SixCy, SixOyCz, ZrCh. TiOxNy, and combinations thereof. In some implementations, the scratch-resistant layer 150 may include SisN-i. SiNy, SiOxNy, and combinations thereof. In some embodiments, each of the scratch-resistant layers 150 employed in the transparent article 100 may exhibit an effective fracture toughness value greater than about 1 MPa^m and simultaneously exhibits a hardness value greater than about 10 GPa, as measured by a Berkovich Hardness Test.

[0080] Each of the scratch-resistant layers 150, as shown in exemplary form in the transparent article 100 depicted in FIG. 1, can be comprised of any of the foregoing materials such that it exhibits a refractive index (RI) of greater than 1.70, or greater than 1.80. In some implementations, the RI of the scratch-resistant layer 150 is greater than 1.55, 1.60, 1.65, 1.70, 1.75, 1.80, 1.85, or 1.90. For example, the RI of the scratch-resistant layer 150 can be 1.55, 1.60, 1.65, 1.70, 1.75, 1.80, 1.85, 1.9, 1.95, 2.0, 2.05, 2.10, 2.15, 2.20, 2.25, 2.3, 2.35, 2.4, 2.45, 2.5, and all RI values between the foregoing values.

[0081] Each of the scratch-resistant layers 150, as shown in exemplary form in the transparent article 100 depicted in FIG. 1, may be relatively thick as compared with other layers (e.g., low RI layers I30A. high RI layers 130B, medium RI layers 130C, capping layer 131, etc.) such as greater than or equal to about 50 nm, 75 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 325 nm, 350 nm, 375 nm, 400 nm, 425 nm, 450 nm, 475 nm, 500 nm, 525 nm, 550 nm, 575 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1 micron, 1.5 microns, or even 2 microns. For example, a scratch-resistant layer 150 may have a thickness from about 50 nm to about 3 microns, from about 100 nm to about 2.5 microns, from about 150 nm to about 2 microns, from about 500 nm to 2500 nm, from about 500 nm to about 2000 nm, from about 500 nm to about 1500 nm, and all thickness levels and ranges between the foregoing ranges. In other implementations, the scratch-resistant layer 150 may have a thickness from about 100 nm to about 2,000 nm, from about 500 nm to about 1500 nm, or from about 750 nm to about 1250 nm.

[0082] As shown in FIG. 1, and outlined above, the transparent articles 100 of the disclosure include an optical film structure 120 with one or more of an outer structure 130a and inner structure 130b. The optical film structure 120 includes a scratch-resistant layer 150, at least one low RI layer 130A, at least one medium RI layer 130C, and at least one high RI layer BOB. In embodiments, the optical film structure 120 includes a plurality of alternating low RI and high RI layers, BOA and BOB, respectively. The outer structure 130a of the optical film structure 120 includes a plurality of alternating medium RI and high RI layers, 130C and BOB. In some embodiments, the inner structure 130b includes a plurality of alternating low RI and high RI layers, BOA and BOB, respectively. In other embodiments, the inner structure 130b includes one or more layers having a graduated or gradient in refractive index, e.g., with refractive index values that span between the refractiveindex ranges of low RI and high RI layers 130A, 13 OB, respectively, or between the refractive index values of the glass-ceramic substrate 110 and the scratch resistant layer 150. In some preferred implementations, the outer structure 130a includes at least one medium RI layer 130C in contact with one of the high RI layers 130B and the scratch-resistant layer 150. In some preferred implementations, the outer structure 130a is inclusive of at least one outermost capping layer 131 (e.g., with a refractive index within the range of those specified for low RI layers 130A), as depicted in exemplary form in FIG. 1.

[0083] According to embodiments, each of the outer and inner structures 130a and 130b includes a period 132 of two or more layers, such as the low RI layer 130A and high RI layer 130B; or a low RI layer 130A, high RI layer 130B and a low RI layer 130A; or a high RI layer 130B and a medium RI layer 130C. Further, each of the outer and inner structures 130a and 130b of the optical film structure 120 may include a plurality of periods 132, such as 1 to 30 periods, 1 to 25 periods, 1 to 20 periods, and all periods within the foregoing ranges. In addition, the number of periods 132, the number of layers of the outer and inner structures 130a and 130b, and / or the number of layers within a given period 132 can differ or they may be the same. Further, in some implementations, the total amount of the plurality of alternating low RI and high RI layers 130A and 130B and / or medium RI layers 130C and high RI layers 130B, along with the scratch-resistant layer 150, may range from 6 to 50 layers, 6 to 40 layers, 6 to 30 layers, 6 to 28 layers, 6 to 26 layers, 6 to 24 layers, 6 to 22 layer, 6 to 20 layers, 6 to 18 layers, 6 to 16 layers, and 6 to 14 layers, and all ranges of layers and amounts of layers between the foregoing values. In a preferred implementation, the the total amount of the plurality of alternating low RI and high RI layers 130A and 130B and / or medium RI layers 130C and high RI layers 130B, along with the scratch-resistant layer 150, may range from 15 to 23 layers (e.g., 19 layers).

[0084] As an example, in FIG. 1, each of the periods 132 of the inner and outer structures 130a, 130b, respectively, includes a low RI layer 130A and a high RI layer BOB or a medium RI layer 130C and a high RI layer BOB. When a plurality of periods is included in either or both of the outer and inner structures 130a and 130b, the low RI layers BOA (designated as “L”), the medium RI layers 130C (designated “M”), and the high RI layers BOB (designated as “H”) can alternate in the following sequence of layers: L / H / L / H . . . , H / L / H / L . . . , M / H / M / H . . ., H / M / H / M . . ., such that the low RI layers BOA and the high RIlayers 130B, or the medium RI layers 130C and the high RI layers 130B, alternate along the physical thickness of the outer and inner structures 130a, 130b of the optical fdm structure 120. In preferred implementations, as shown in FIG. 1, the periods 132 in the outer structures 130a are configured as M / H / M / H . . . above the scratch-resistant layer 150; and the periods 132 in the inner structures 130b are configured as L / H / L / H . . . above the glass-ceramic substrate 110 and beneath the scratch-resistant layer 150.

[0085] In an implementation of the transparent article 100, as shown in FIG. 1, the number of periods 132 of the outer and inner structures 130a and 130b can be configured such that the outer structure 130a includes a total of eight (8) alternating layers (e.g., alternating medium and high RI layers 130C and 130B); and the inner structure 130b includes at least nine (9) layers (e.g., alternating low RI and high RI layers 130A, BOB, respectively). Further, in this implementation, the outer structure 130a of the optical film structure 120 includes a capping layer 131 (similar in structure and thickness to a low RI layer BOA) over the outer structure 130a; and the optical film structure 120 includes a scratch-resistant layer 150 disposed between the outer and inner structures 130a and 130b. Accordingly, in the implementation depicted in exemplary form in FIG. 1, the optical structure 120 includes a total of 19 layers.

[0086] According to some implementations of the transparent articles 100 of the disclosure, each of the outer and inner structures 130a and 130b of the optical film structure 120 has a total of at least 7, 8, 9, 10, 11, 12, 13, 14, or even 15 layers. According to some embodiments of the transparent articles 100 of the disclosure, the optical film structure 120 has atotal of at least 15, 16, 17, 18, 19, 20, 25, or even 30 layers. In one preferred implementation of the transparent article 100, as depicted in FIG. 1, the outer structure 130a includes at least four (4) medium RI layers 130C, at least four (4) high RI layers BOB, and one of the high RI layers BOB is in contact with an outermost capping layer 131 (e.g., a low RI layer BOA).

[0087] According to some embodiments of the transparent article 100 depicted in FIG. 1, the outermost capping layer 131 of the optical film structure 120 and outer structure 130a may not be exposed but instead have a top coating 140 disposed thereon. In some implementations of the transparent article 100, each high RI layer BOB of the optical film structure 120, along with the outer and inner structures 130a, 130b, comprises a nitride, asilicon-containing nitride (e.g., SiNy, SisN^, an oxynitride, or a silicon-containing oxynitride (e.g., SiAlxOyNz or SiOxNy). Further, according to some embodiments, each low RI layer 130A of the optical film structure 120, along with the outer and inner structures 130a, 130b, comprises an oxide, a silicon-containing oxide (e.g., SiCh, SiOxor SiCh as doped with Al, N or F), or a silicon-containing oxynitride (e.g., SiOxNy). In addition, according to some embodiments, the scratch-resistant layer 150 and each medium RI layer 130C of the optical film structure 120 comprises an oxynitride or a silicon-containing oxynitride (e.g., SiAlxOyNzor SiOxNy). In a preferred implementation of the transparent article 100 depicted in FIG. 1, the outer structure 130a comprises a plurality of alternating high RI layers 130B of SiNxand medium RI layers 130C of SiOxNy(along with an optional capping layer 131 of SiO2 or SiOxNy); and the inner structure 130b comprises a plurality of alternating high RI layers 130B of SiOxNy and low RI layers 130A of SiO2.

[0088] In one or more embodiments of the transparent article 100 depicted in FIG. 1, the term “low RI”, when used with the low RI layers 130A and / or capping layer 131, includes a refractive index range of less than 1.7, from about 1.3 to about 1.55, from about 1.35 to about 1.55, from about 1.35 to about 1.7, from about 1.4 to about 1.5, from about 1.45 to about 1.5, and all indices within these ranges. In one or more embodiments, the term “medium RI”, when used with the medium RI layers 130C and / or scratch-resistant layer 150, includes a refractive index range from 1.5 to 1.9, from 1.5 to 1.85, 1.55 to 1.9, 1.55 to 1.80, 1.55 to 1.65, 1.56 to 1.80, 1.6 to 1.75, and all indices within these ranges. In one or more embodiments, the term “high RI”, when used with the high RI layers 130B and / or scratch-resistant layer 150, includes a refractive index range of greater than 1.80, greater than 1.90, from about 1.8 to about 2.5, from about 1.8 to about 2.3, from about 1.85 to about 2.1, from about 1.9 to about 2. 1, or from about 1.90 to about 2.5, and all indices between these ranges. Further, in a specific implementation, the medium RI layer(s) of the transparent articles 100 of the disclosure (see, e.g., FIG. 1), may include a refractive index range from 1.55 to 1.90, 1.55 to 1.85, 1.55 to 1.75, 1.55 to 1.65, and all values between these ranges. In one or more embodiments, the difference in the refractive index of each of the low RI layers 130A (and / or capping layer 131), the medium RI layers 130C (and / or scratch-resistant layer 150), and / or the high RI layers 130B (and / or scratch-resistant layer 150) may be about 0.01 or greater, about 0.05 or greater, about 0.1 or greater, or even about 0.2 or greater. In general, for a givenembodiment, the definition of which layers in the optical film structure 120 are high RI, medium RI, and low RI will be defined by their relative values, that is, the RI value of the high RI layers 130B is greater than the RI value of the medium RI layers 130C, and the RI value of the medium RI layers 130C is greater than the RI value of the low RI layers 130A.

[0089] Example materials suitable for use in the outer and inner structures 130a and 130b of the optical film structure 120 of the transparent article 100 depicted in FIG. 1 include, without limitation, SiO2. SiOx, AI2O3, SiAlxOy, GcO2. SiO, A10xNy, AIN, A1NX, SiAlxNy, SiNy, SiOxNy, SiAlxOyNz, Ta2O5, Nb2O5, TiO2, ZrO2, TiN, MgO, MgF2, BaF2,CaF2, SnO2, HfO2, Y2O3, MoOs, DyF,. YbFs. YF3, CcFs. diamond-like carbon and combinations thereof. Some examples of suitable materials for use in a low RI layer 130A and the outermost capping layer 131 include, without limitation, SiO2, SiOx, AI2O2. SiAlxOy, GeO2, SiO, A10xNy, SiOxNy, SiAlxOyNz, MgO, MgAlxOy, MgF2, BaF2, CaF2, DyF3, YbF3, YF3, and CcFv In some implementations of the transparent article 100, each of its low RI layers 130A includes a silicon-containing oxide (e.g., SiO2or SiOx) or a silicon-containing oxynitride (e.g., SiOxNy). The nitrogen content of the materials for use in a low RI layer 130A may be minimized (e.g., in materials such as SiOxNy, Al2Os and MgAlxOy). Some examples of suitable materials for use in a high RI layer 130B include, without limitation, SiAlxOyNz, Ta2O5, Nb2O5, AIN, A1NX, SiAlxNy, AlNx / SiAlxNy, Si3N4, A10xNy, SiOxNy, SiNy, SiNx:Hy, HfO2, TiO2, ZrO2, Y2O3, Al2Os, MoOs, and diamond-like carbon. Some examples of suitable materials for use in a medium RI layer 130C include, without limitation, SiAlxOyNz, A10xNy, SiOxNy, HfO2, Y2O3, and AI2O2. According to some implementations, each high RI layer 130B of the outer and inner structures 130a, 130b includes a silicon-containing nitride or a silicon-containing oxynitride (e.g., SisN-i. SiNy, or SiOxNy). In one or more embodiments, each of the high RI layers BOB may have high hardness (e.g., hardness of greater than 8 GPa), and the high RI materials listed above may comprise high hardness and / or scratch resistance.

[0090] The oxygen content of the materials for the high RI layer BOB may be minimized, especially in SiNymaterials. Further, exemplary SiOxNyhigh RI materials may comprise from about 0 atom% to about 20 atom% oxygen, or from about 5 atom% to about 15 atom% oxygen, while including 30 atom% to about 50 atom% nitrogen. The foregoing materials may be hydrogenated up to about 30% by weight. Where a material having a medium refractiveindex is desired as a medium RI layer 130C, some embodiments may utilize SiOxNy, e.g., with a relatively low level of nitrogen (e.g., less than 10%, less than 5%, or less than 3%). It should be understood that a scratch-resistant layer 150 of the transparent articles 100 may comprise any of the materials disclosed as suitable for use in a high RI layer 13 OB or a medium RI layer 130C.

[0091] In one or more embodiments of the transparent article 100, the optical fdm structure 120 includes a scratch-resistant layer 150 that can be integrated as a medium RI layer 130C, and one or more low RI layers 130A, high RI layers 130B, medium RI layers 130C, and / or a capping layer 131 may be positioned over the scratch-resistant layer 150. Also, with regard to the scratch-resistant layer 150, as shown in FIG. 1, an optional top coating 140 may also be positioned over the layer 150. The scratch-resistant layer 150 may be alternately defined as the thickest medium RI layer 130C in the overall optical film structure 120 and / or in the outer and the inner structures 130a, 130b.

[0092] Without being bound by theory, it is believed that the transparent article 100 depicted in FIG. 1 may exhibit increased hardness at low indentation depths (e.g., 100-125 nm) when one or more medium RI layers 130C (e.g., as comprising SiOxNy) is placed in direct contact with one or more high RI layers 130B (e.g., SiOxNy, SiNy) in the outer structure 130a; the outer structure 130a is comprised of alternating layers of high RI layers 130B and medium RI layers 130C (which replaces alternating high RI layers 130B and low RI layers 130A in known optical film structures); the sum of the physical thicknesses of the low RI layers 130A and / or the capping layer 131 in the outer structure 130a is minimized; and the total thickness of the layers in the outer structure 130a is minimized. In some implementations, an additional, repeating medium RI layer 130C can be deployed in the outer structure 130a in contact with another medium RI layer 130C or scratch-resistant layer 150 to also increase hardness at shallow depths within the optical film structure 120. According to some implementations, the sum of the physical thicknesses of the low RI layers 130A and / or the capping layer 131 in the outer structure 130a is configured to be less than about 15 nm, less than about 250 nm, less than about 225 nm, less than about 200 nm, less than about 175 nm, less than about 150 nm, less than about 125 nm, less than 110 nm, less than 100 nm, less than 90 nm, less than 75 nm, or even less than 65 nm, which can also increase hardness at shallow depths within the optical film structure 120. For example, the sum of the physicalthicknesses of the low RI layers 130A and / or the capping layer 131 in the outer structure 130a can be 250 nm, 225 nm, 200 nm, 175 nm, 150 nm, 125 nm, 120 nm, 110 nm, 100 nm, 90 nm, 80 nm, 70 nm, and all total thickness values between the foregoing values. Further, in some implementations, the total physical thickness of the layers in the outer structure 130a of the transparent articles 100 depicted in FIG. 1 can be configured to be less than 1000 nm, less than 900 nm, or less than 800 nm, and greater than 400 nm, 450 nm, or even 500 nm, and all total thickness values in the foregoing ranges.

[0093] Throughout the disclosure, “surface-modifying layer” refers to a layer that is characterized by changing a physical property or other behavior of the coated article. For example, a surface -modifying layer can modify one or more of a water contact angle, an oleic contact angle, a visibility of a fingerprint (e.g., simulated fingerprint), and / or an ability to remove a fingerprint (e.g., by wiping). In one or more embodiments, the transparent article 100 depicted in FIG. 1 may include one or more additional top coatings 140 disposed on the outer structure 130a of the optical film structure 120. In one or more embodiments, the additional top coating 140 may include a surface modifying layer such as a fingerprint hiding coating, anti-fingerprint hiding layer or an easy-to-clean coating. Examples of a suitable antifingerprint hiding layer and easy-to-clean coatings are described in the following U.S. patent applications: U.S. Patent Application Publication No. 2014 / 0113083, published on April 24, 2014, entitled “Process for Making of Glass Articles with Optical and Easy-to-Clean Coatings”; U.S. Patent Application No. 18 / 932,938, filed on October 31, 2024, entitled “Coated Articles with a Planarization Layer and a Surface-Modifying Layer and Methods of Making the Same”; U.S. Non-Provisional Patent Application No. 18 / 528,916, filed on December 5, 2023, entitled “Coated Articles with an Anti-Fingerprint Coating or Surface- Modifying Layer and Methods of Making the Same”, and PCT Patent Application No. PCT / US24 / 57255, filed on November 25, 2024, entitled “Coated Articles with a Surface- Modifying Layer and Methods of Making the Same”, all of which are incorporated herein by reference in their entirety. The easy-to-clean coating can be a fluorine-containing material. Alternatively, the easy-to-clean coating (anti-fingerprint coating) can include a partial silica- like network having a ratio of Si-O-Si bonds to Si atoms in the coating from about 2 to about 3, the coating is fluorine-free, and the coating further comprises an alkyl silane at the exterior surface and bonded to Si-0 groups in the anti-fingerprint coating. The easy-to-clean coatingmay have a thickness in the range from about 5 nm to about 50 nm and may include known materials such as fluorinated or non-fluorinated silanes. The easy-to-clean coating may alternately or additionally comprise a low-friction coating or surface treatment. Exemplary low-friction coating materials may include diamond-like carbon, silanes (e.g., fluorosilanes), phosphonates, alkenes, and alkynes. In some embodiments, the easy-to-clean coating of the top coating 140 may have a thickness in the range from about 1 nm to about 40 nm, from about 1 nm to about 30 nm, from about 1 nm to about 25 nm, from about 1 nm to about 20 nm, from about 1 nm to about 15 nm, from about 1 nm to about 10 nm, from about 5 nm to about 50 nm, from about 10 nm to about 50 nm, from about 15 nm to about 50 nm, from about 7 nm to about 20 nm, from about 7 nm to about 15 nm, from about 7 nm to about 12 nm, from about 7 nm to about 10 nm, from about 1 nm to about 90 nm, from about 5 nm to about 90 nm, from about 10 nm to about 90 nm, or from about 5 nm to about 100 nm, and all ranges and sub-ranges therebetween.

[0094] In aspects, the surface-modifying layer employed as the top coating 140 can be an anti-fingerprint coating. Throughout the disclosure, a surface-modifying layer is an “antifingerprint” coating if the coating on a glass-based substrate can reduce the visibility of, reduce a color shift of, and / or reduce droplet formation of fingerprint oil disposed thereon relative to the glass-based substrate without the coating. As used herein, the visibility of a fingerprint refers to an absolute value of a difference in brightness (e.g., CIELAB L* value) for a portion of the anti-fingerprint coating with the fingerprint oil and another portion of the anti-fingerprint coating without the fingerprint oil. As used herein, the color shift of the glassbased substrate refers to a difference in measured color as "V((ai* - a?*)2+ (bi* - b2*)2), where a* refers to CIELAB a* values, b* refers to CIELAB b* values, subscript 1 refers to a portion of the anti-fingerprint coating without fingerprint oil, and subscript 2 refers to a portion of the anti -fingerprint coating with fingerprint oil. An anti-fingerprint coating can reduce droplet formation, which can increase a visibility and / or color shift of fingerprint oil, by being oleophilic, as defined below. Additionally, the anti-fingerprint coating can enable the removal of aqueous material (e.g., water droplets, sweat droplets) from the coating, for example, by being hydrophobic, as defined below. In further aspects, the anti-fingerprint coating can exhibit an (e.g., as-formed) water contact angle from 90° to 120°, an (e.g., as-formed) oleic acid contact angle of 40° or less, and a coefficient of friction of 0.25 or less. In furtheraspects, the easy-to-clean coating can be substantially free and / or free of fluorine. In aspects, a diiodomethane contact angle of an anti-fingerprint coating (e.g., as-formed) can be about 60° or more, about 62° or more, about 65° or more, about 80° or less, about 75° or less, about 73° or less, or about 70° or less. In aspects, a diiodomethane contact angle of an antifingerprint coating (e.g., as-formed) can range from about 60° to about 80°, from about 62° to about 75°, from about 65° to about 72°, or any range or subrange therebetween. In aspects, an anti-fingerprint coating can be oleophilic. In aspects, a hexadecane contact angle and / or an oleic acid contact angle of an anti-fingerprint coating (e.g., as-formed) can be about 45° or less, about 40° or less, about 30° or less, about 25° or less, about 20° or less, or the antifingerprint coating can wet hexadecane and / or oleic acid. In further aspects, the antifingerprint coating (e.g., as formed) wets hexadecane and / or oleic acid. Providing a low diiodomethane contact angle (e.g., about 60° or less) and / or a low hexadecane contact angle (e.g., about 30° or less) can reduce the visibility and / or color shift associated with fingerprints by enabling fingerprint oil to be dispersed across the anti-fingerprint coating rather than beading up into pronounced droplets.

[0095] In aspects, the surface-modifying layer employed as the top coating 140 can be an easy-to-clean coating. Throughout the disclosure, a surface-modifying layer is an “easy-to- clean” coating if the coating on a glass-based substrate can repel material and / or facilitate removal of material disposed thereon relative to the glass-based substrate without the coating. As used herein, an ability to repel material is determined based on a contact angle with higher contact angles associated with greater repulsion. As used herein, an ability to remove material is measured by wiping the material disposed on the surface (e.g., coating or glass-based substrate) with a cheesecloth (see details from the Cheesecloth Abrasion Test with the modification that the material is disposed on the surface before wiping) and the visibility of the material is monitored. A decreased visibility (e.g., fewer wiping cycles to achieve a predetermined reduction is visibility) is associated with a coating facilitating removal of material disposed thereon. In further aspects, the easy-to-clean coating can exhibit an (e.g., as-formed) water contact angle from 90° to 120°, an (e.g., as-formed) oleic acid contact angle of 50° or more, and a coefficient of friction of 0.25 or less. In further aspects, the easy-to- clean coating can be a fluorine-containing material. Alternatively, in further aspects, the easy- to-clean coating can be substantially free and / or free of fluorine. In aspects, a diiodomethanecontact angle of an anti-fingerprint coating (e.g., as-formed) can be about 60° or more, about 62° or more, about 65° or more, about 80° or less, about 75° or less, about 73° or less, or about 70° or less. In aspects, a diiodomethane contact angle of an anti-fingerprint coating (e.g., as-formed) can range from about 60° to about 80°, from about 62° to about 75°, from about 65° to about 72°, or any range or subrange therebetween. In aspects, the anti-fingerprint coating can be oleophilic. In aspects, a hexadecane contact angle of the anti -fingerprint coating (e.g., as-formed) can be about 45° or less, about 40° or less, about 30° or less, about 25° or less, about 20° or less, or the an anti-fingerprint coating can wet hexadecane. In further aspects, the anti-fingerprint coating (e.g., as formed) wets hexadecane. Providing a low diiodomethane contact angle (e.g., about 60° or less) and / or a low hexadecane contact angle (e.g., about 30° or less) can reduce the visibility and / or color shift associated with fingerprints by enabling fingerprint oil to be dispersed across the surface-modifying layer rather than beading up into pronounced droplets.

[0096] In aspects, the top coating 140 can comprise one or more surface-modifying layers. Suitable surface-modifying layers may include at least one alkyl silane layer. The at least one alkyl silane layer could be bonded directly to the capping layer 131, e.g., at the outer surface 120a of the transparent article 100 (see FIG. 1). In some embodiments, a surface-modifying layer of the top coating 140 can be bonded to an underlying layer of the top coating 140 (e.g., the OB-PSS layer shown in FIG. IB, as described further below). The at least one alkyl silane may include one or more bipodal alkyl silanes, such as 1,8- bis(chlorodimethylsilyl) octane, l,6-bis(trichlorosilyl) hexane, bis(triethoxysilyl) methane, l,2-bis(triethoxysilyl) ethane, I,6-bis(trimethoxysilyl) hexane, l,8-bis(triethoxysilyl) octane, I,8-bis(trimethoxysilyl) octane, or combinations thereof in addition to one or more monopodal alkyl silanes, such as octadecyl trimethoxysilane (OTS), dodecyl trimethoxy silane, or combinations thereof. In an implementation, the surface-modifying layers may include an OTS layer, as bonded to an underlying layer of the top coating 140 (e.g., the OB-PSS layer shown in FIG. IB, and described in further detail below).

[0097] In aspects, the top coating 140 can comprise one or more planarization layers. Suitable planarization layers of the top coating 140 can comprise a silica-like structure, e.g., as derived from a functionalized octa-isobutyl polyhedral oligomeric silsesquioxane (OB- PSS), that is bonded directly to the capping layer 131, e.g., at the outer surface 120a of thetransparent article 100 (see FIG. 1) or to a layer of the top coating 140 (e.g., the OTS layer shown in FIG. IB). As used herein, a polyhedral oligomeric silsesquioxane (PSS) refers to a functionalized oligomer silsesquioxane consisting of RSiOi.s monomers. Exemplary aspects of functionalized PSS can comprise 6, 8, 10, or 12 RSiOi.s monomers, although other aspects are possible. For example, functionalized oligomeric silsesquioxane consisting of 8 RSiOi.s monomers is an octahedral functionalized POSS (e.g., polyoctahedral silsesquioxane).

[0098] In addition, the one or more planarization layers employed in the top coating 140 can serve to provide a decreased surface roughness (Ra) relative to what would be obtained in a transparent article (e.g., the transparent article 100b depicted in FIG. IB) without the planarization layer, which enables the transparent article including the planarization layer to benefit from the increased abrasion resistance of a surface-modifying layer (see above, e.g., OTS layer). In aspects, the planarization layer can provide a reduced surface roughness relative to a surface roughness of an underlying layer, as a ratio of the surface roughness (Ra) of the planarization layer to the surface roughness (Ra) of its underlying layer (e.g., the capping layer 131), can be 0.9 or less (e.g., from 0.1 to 0.9, from 0.2 to 0.8, or from 0.3 to 0.7). In embodiments, the planarization layer can exhibit a surface roughness (Ra) of from 0. 1 nm to 4 nm, 0. 1 nm to 3 nm, 0. 1 nm to 2 nm, and all surface roughness values between the foregoing.

[0099] Referring again to the one or more planarization layers that can be employed in the top coating 140, these layer(s) can be readily distinguished from other silicon-containing oxides (e.g., a capping layer 131 comprising silica or the substrate 110) by the properties discussed herein (e.g., hydroxyl content, hardness, refractive index, power spectral density of the surface, surface roughness (Ra), molar ratio of hydrogen to silica). For example, the planarization layer can comprise a greater hydroxyl content than a hydroxyl content of the capping layer 131; the planarization layer can exhibit a lower hardness, lower elastic modulus, and / or higher refractive index than the corresponding property of the capping layer 131; and / or a surface roughness (Ra) of the planarization layer can be less than a surface roughness (Ra) of the capping layer 131. Additionally, for example, the planarization layer can comprise a greater molar ratio of hydrogen to silica than a molar ratio of hydrogen to silica of the substrate 110. In some implementations, the molar ratio of hydrogen to silica inthe planarization layer is about 0.2 or more, 0.2 to 0.4, 0.22 to 0.35, or any molar ratio values in the foregoing ranges.

[0100] Throughout the disclosure, the “molar ratio” refers to a molar ratio of hydrogen to silicon (i.e., a molar amount of hydrogen divided by a molar amount of silicon) as determined by SIMS analysis of a material (e.g., planarization layer of the top coating 140). Without wishing to be bound by theory, it is believed that hydrogen is indicative of hydroxyl groups (e.g., silanol, Si-O-H). In aspects, a molar ratio (of hydrogen to silicon) can be about 0.2 or more (e.g., about 0.2 or more), about 0.21 or more, about 0.22 or more, about 0.23 or more, about 0.24 or more, about 0.25 or more, about 0.45 or less, about 0.4 or less, about 0.37 or less, about 0.35 or less, about 0.32 or less, about 0.30 or less, or about 0.28 or less. In aspects, a molar ratio (of hydrogen to silicon) can be in a range from about 0.2 to about 0.45, from about 0.20 to about 0.4 (e.g., from about 0.2 to about 0.4), from about 0.21 to about 0.37, from about 0.22 to about 0.35, from about 0.23 to about 0.32, from about 0.24 to about 0.32, from about 0.24 to about 0.30, from about 0.25 to about 0.28, or any range or subrange therebetween. In exemplary aspects, the molar ratio of hydrogen to silicon can be in a range from 0.20 to 0.4 or from about 0.22 to about 0.35. For example, the planarization layer(s) of the top coating 140 in accordance with aspects of the present disclosure exhibits a molar ratio of hydrogen to silicon of 0.20 or more, from about 0.20 to 0.4, or from about 0.22 to about 0.35. In contrast, conventional methods of silica deposition have a molar ratio of about 0.10 or less. In aspects, the molar ratio at the surface of the planarization layer(s) can be within any of the ranges recited above in this paragraph. In aspects, the molar ratio (of hydrogen to silicon) of the planarization layer of the top coating 140 can be greater than the molar ratio of a reactively sputtered silica layer by a multiple of 2 or more, 2.5 or more, 3 or more, 4 or more, 10 or less, 7 or less, 5 or less, or 4 or less. In aspects, the molar ratio (of hydrogen to silicon) of the planarization layer can be greater than the molar ratio of a reactively sputtered silica layer by a multiple in a range from about 2 to 10, from 2 to 7, from 2.5 to 5, from 2.5 to 4, from 3 to 4, or any range or subrange therebetween. In aspects, an ion intensity of carbon (as a ratio to the ion intensity of silicon) can be about 0.01 or less, about 0.005 or less, about 0.002 or less, or about 0.001 or less, for example, in a range from about 0.00001 to about 0.01, from about 0.00005 to about 0.005, from about 0.0001 to about 0.002, from about 0.0005 to about 0.001, or any range or subrange therebetween. The intensity of carbon isbased on measurements that are corrected to remove background signals (as determined from the intensity of carbon measured from fused quartz).

[0101] Further, functionalized oligomeric silsesquioxanes of the one or more planarization layers can be functionalized by one or more functional groups. A functional group functionalizing the functionalized oligomeric silsesquioxane can exclude hydrogen. In aspects, the functional group functionalizing the functionalized oligomeric silsesquioxane can exclude bisphenols, fluorine -containing functional groups isocyanates, epoxies, glycidyls, oxirane, sulfur-containing functional groups (e.g., thiols), anhydrides, acrylates, methacrylates, and / or alkynes. In aspects, the functional group functionalizing the functionalized oligomeric silsesquioxane can be an alkyl group, an alkene group, an aromatic group (e.g., a phenyl group), a silane (e.g., alkyl silyl group), or combinations thereof. As used herein, an alkyl group contains a saturated hydrocarbon with carbon-carbon single bonds and hydrogen bonded to carbon atoms. In aspects, alkyl functional groups can range from 1 to 10 carbons (i.e., Ci-Cio alkyl), for example, from 1 to 8 carbons (i.e., Ci-Cs alkyl) or from 1 to 4 carbons (i.e., C1-C4 alkyl). Exemplary aspects of alkyl functional groups include methyl and isobutyl. An exemplary aspect of an aromatic functional group is a phenyl group. An exemplary aspect of a silane includes a dimethylsilyl group. As used herein, an alkene group contains an unsaturated hydrocarbon with one or more carbon-carbon double bonds. Alkenes can optionally include one or more carbon-carbon single bonds (e.g., alkyl chains in the alkene group). In even further aspects, the functionalized POSS can be at least partially functionalized by alkenes containing from 2 to 8 carbons (i.e., C2-C8 alkenes). An exemplary aspect of an alkene functionalized PSS is a vinyl PSS, for example, partially vinyl functionalized vinyl / isobutyl PSS (OL1123 available from Hybrid Plastics) or octa-vinyl PSS (OL1170 available from Hybrid Plastics). An exemplary aspect of an aromatic functionalized PSS is octaphenyl PSS (MS0840 available from Hybrid Plastics). Exemplary aspects of alkyl functionalized PSS are octamethyl PSS (MS0830 available from Hybrid Plastics) and OB- PSS (MS0825 available from Hybrid Plastics).

[0102] According to an embodiment, atop coating 140 comprising a planarization layer, e.g., a layer that comprises a silica-like structure (e.g., as derived from a functionalized octaisobutyl polyhedral oligomeric silsesquioxane (OB-PSS) or a polyhedral oligomeric silsesquioxane (PSS)), can be subjected to an ion beam treatment. In particular, properties ofthe planarization layer can be controlled by the discharge current of the ion beam. For a KRI EH-400 End-Hall ion source in a Angstrom Evovac chamber operating at 100V, providing a discharge current of about 0.25 A or more can facilitate the formation of the coating, for example, producing an ion beam with sufficient energy to cause the functionalized PSS to react with other functionalized PSS and / or the first major surface 112 of the substrate 110 at an appreciable rate (e.g., compared to lower discharge currents). Providing a discharge current of about 1 A or less to the ion beam source facilitates deposition of a condensed PSS material. The ion beam discharge can facilitate condensation of the functionalized PSS converting at least a portion of the cage structure of the functionalized PSS to a silica or a partial Si-O-Si-O network (e.g., of the underlying capping layer 131 comprising SiCh). Functionalized PSS is evaporated and subjected to ion beam to create a silica or a partially condensed silica-like network at or near room temperature. Alternatively, the substrate that the thermally evaporated functionalized PSS condenses on and the ion beam impinges can be heated. Substrate temperature during PSS deposition is 250°C or less, 200°C or less, 100°C or less, or preferably 50°C or less.

[0103] According to an implementation of the transparent article 100b depicted in FIG. IB, the top coating 140 can include at least one surface-modifying layers, e.g., OTS, and at least one planarization layer, e.g., a layer comprising a silica-like structure derived from OB- PSS. From an optical standpoint, each of the OTS- and OB-PSS-containing layers has a refractive index that is substantially similar to that of the low RI material used in the capping layer 131, e.g., SiO2. In embodiments, each of the OTS and OB-PSS-containing layers has a physical thickness that ranges from 1 nm to 60 nm, 1 run to 50 nm, 5 nm to 50 nm, and all physical thickness values between the foregoing ranges. In embodiments, the OTS layer of the top coating 140 has a physical thickness that ranges from 1 nm to 10 nm or 2 nm to 10 nm, e.g., 1 nm, 1.5 nm, 2 nm, 2.5 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, and all thickness values between the foregoing. In embodiments, the OB-PSS layer of the top coating 140 has a physical thickness that ranges from 5 nm to 60 nm, 10 nm to 60 nm, 10 nm to 50 nm or 15 nm to 50 nm, e.g., 10 nm, 12.5 nm, 15 nm, 17.5 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, and all thickness values between the foregoing. In some embodiments, the physical thicknesses of the capping layer 131, as comprising SiCh, and OB- PSS-containing layer can be balanced and adjusted to maintain desired optical properties andadjust mechanical properties of the optical film structure 120, recognizing that the OB-PSS- containing layer and capping layer 131 have the same refractive index values. For example, in an embodiment, the capping layer 131 has a physical thickness of 16 nm and the OB-PSS- containing layer has a physical thickness of 38 nm (see Table 6A, Ex. 7A below), whereas in another embodiment the capping layer 131 is thicker with a physical thickness of 34 nm and the OB-PSS-containing layer is thinner with a physical thickness of 20.0 nm (see Table 6B, Ex. 7B below).

[0104] The top coating 140 may also include a scratch-resistant layer or layers which comprise any of the materials disclosed as being suitable for use in the scratch-resistant layer 150. In some embodiments, the additional top coating 140 includes a combination of easy-to- clean material and scratch-resistant material. In one example, the combination includes an easy-to-clean material and diamond-like carbon. Such an additional top coating 140 may have a thickness in the range from about 5 nm to about 20 nm. The constituents of the additional coating 140 may be provided in separate layers. For example, the diamond-like carbon may be disposed as a first layer and the easy-to clean material can be disposed as a second layer on the first layer of diamond-like carbon. The thicknesses of the first layer and the second layer may be in the ranges provided above for the additional coating. For example, the first layer of diamond-like carbon may have a thickness of about 1 nm to about 20 nm or from about 4 nm to about 15 nm (or more specifically about 10 nm) and the second layer of easy-to-clean material may have a thickness of about 1 nm to about 10 nm (or more specifically about 6 nm). The diamond-like coating may include tetrahedral amorphous carbon (Ta-C), Ta-C:H, and / or a-C-H.

[0105] According to embodiments of the transparent article 100 depicted in FIG. 1, each of the low RI layers 130A and high RI layers 130B of the outer and inner structures 130a, 130b of the optical film structure 120 can have a physical thickness that ranges from about 5 nm to 1000 nm, 5 nm to 500 nm, about 5 nm to 250 nm, about 5 nm to 200 nm, and all thicknesses and ranges of thickness between these values. For example, each of these low RI layers 130A and high RI layers 130B can have a physical thickness of 5 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 125 nm, 150 nm, 175 nm, 200 nm, 225 nm, 250 nm, and all thickness values between these levels. Further, according to embodiments of the transparent article 100 depicted in FIG. 1, each of the scratch-resistantlayer 150 and medium RI layers 130C of the outer and inner structures 130a, 130b of the optical fdm structure 120 can have a physical thickness that ranges from about 5 nm to 2500 nm, 5 nm to 2000 nm, about 5 nm to 1500 nm, about 5 nm to 1000 nm, and all thicknesses and ranges of thickness between these values. For example, each of the medium RI layers 130C (as not employed as a scratch-resistant layer 150) can have a physical thickness of 5 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 125 nm, 150 nm, 175 nm, 200 nm, 225 nm, 250 nm, and all thickness values between these levels.Further, according to some implementations, each of the low RI layers 130A (e.g., a capping layer 131), medium RI layers 130C and high RI layers 130B of the outer structure 130a can have a physical thickness that ranges from about 5 nm to 250 nm, about 5 nm to 200 nm, about 5 nm to 175 nm, and all thicknesses and ranges of thickness between these values. As an example, each of these layers 130A-130C can have a physical thickness of 5 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 125 nm, 150 nm, 175 nm, 200 nm, 225 nm, 250 nm, and all thickness values between these levels.

[0106] Referring to FIG. 1A, a transparent article 100a is shown according to one or more embodiments. The transparent article 100a is the same as the aforementioned transparent article 100 (see FIG. 1 and corresponding description) with like numbered elements having the same or similar structures and functions, except for the following differences. Further, unless otherwise noted, the mechanical, material and optical properties of the transparent article 100a and its outer and inner structures 130a and 130b, respectively, described in this disclosure are also exhibited by the transparent article 100b depicted in exemplary form in FIG. 1A. The transparent article 100 includes the outer structure 130a with a plurality of alternating medium RI layers 130C and high RI layers 130B, and the inner structure 130b includes a plurality of alternating low RI layers 130A and high RI layers 130B (e.g., see below Examples 3-4). In contrast, the transparent article 100a shown in exemplary form in FIG. 1A includes the outer structure 130a with a plurality of alternating high RI layers 130B and low RI layers BOA, and the inner structure 130b includes a plurality of alternating low RI layers BOA and high RI layers BOB (e.g., see below Example 5). In some implementations of article 100a, the high RI layers and the low RI layers of the inner structure are SiOxNyand SiCh, respectively, wherein the low RI layers and high RI layers ofthe plurality of alternating low RI and high RI layers of the outer structure are SiNxand SiCh. respectively, and wherein the scratch-resistant layer is SiOxNy.

[0107] Referring to FIG. IB, a transparent article 100b is shown according to one or more embodiments. The transparent article 100b is similar to the aforementioned transparent article 100 (see FIG. 1 and corresponding description) with like numbered elements having the same or similar structures and functions, except for the following differences. Further, unless otherwise noted, the mechanical, material and optical properties of the transparent article 100b and its outer and inner structures 130a and 130b, respectively, described in this disclosure are also exhibited by the transparent article 100b depicted in exemplary form in FIG. IB. The transparent article 100 includes the outer structure 130a with a plurality of alternating medium RI layers 130C and high RI layers BOB, and the inner structure 130b includes a plurality of alternating low RI layers BOA and high RI layers BOB (e.g., see below Examples 3-4). In contrast, the transparent article 100b shown in exemplary form in FIG. IB includes the outer structure 130a with a plurality of alternating high RI layers BOB and medium RI layers 130C, and the inner structure 130b includes a plurality of alternating low RI layers BOA and medium RI layers 130C (e.g., see below Exs. 7A & 7B). Further, the transparent article 100b includes a capping layer 131 of a low RI material (e.g., SiCh). along with a top coating 140 that can comprise, according to some embodiments, an OTS layer and an OB-PSS layer. In some implementations of article 100b, the high RI layers BOB and the medium RI layers 130C of the plurality of alternating high and medium RI layers of the outer structure 130a are SiNxand SiOxNy, respectively, wherein the low RI layers BOA and medium RI layers 130C of the plurality of alternating low RI and medium RI layers of the inner structure 130b are SiCh and SiOxNy, respectively, and wherein the scratch-resistant layer 150 / medium RI layer 130C is SiOxNy

[0108] The glass-ceramic substrate 110 of the transparent article 100 depicted in FIG. 1 may include an inorganic material with amorphous and crystalline portions. The substrate 110 may be formed from man-made materials and / or naturally occurring materials (e.g., quartz). In some specific embodiments, the substrate 110 may specifically exclude polymeric, plastic and / or metal substrates. The substrate 110 may be characterized as an alkali-including substrate (i.e., the substrate includes one or more alkalis). In one or more embodiments, the glass-ceramic substrate 110 exhibits a refractive index in the range fromabout 1.5 to about 1.6. In specific embodiments, the glass-ceramic substrate 110 (e.g., a strengthened glass-ceramic substrate) may exhibit an average strain-to-failure at a surface on one or more opposing primary surfaces 112, 114 that is 0.5% or greater, 0.6% or greater, 0.7% or greater, 0.8% or greater, 0.9% or greater, l% or greater, 1.1% or greater, 1.2% or greater, 1.3% or greater, 1.4% or greater, 1.5% or greater or even 2% or greater, as measured using an ROR Test using at least 5, at least 10, at least 15, or at least 20 samples to determine the average strain-to-failure value. In specific embodiments, the glass-ceramic substrate 110 may exhibit an average strain-to-failure at its surface on one or more opposing primary surfaces 112, 114 of about 1.2%, about 1.4%, about 1.6%, about 1.8%, about 2.2%, about 2.4%, about 2.6%, about 2.8%, or about 3% or greater.

[0109] The term “strain-to-failure” refers to the strain at which cracks propagate in the outer or inner structures 130a, 130b of the optical film structure 120, substrate 110, or both simultaneously without application of additional load, typically leading to catastrophic failure in a given material, layer or film and perhaps even bridge to another material, layer, or film, as defined herein. That is, breakage of the optical film structure 120 (i.e., as including outer and / or inner structures 130a, 130b) without breakage of the substrate 110 constitutes failure, and breakage of the substrate 110 also constitutes failure. The term “average” when used in connection with average strain-to-failure or any other property is based on the mathematical average of measurements of such property on 5 samples. Typically, crack onset strain measurements are repeatable under normal laboratory conditions, and the standard deviation of crack onset strain measured in multiple samples may be as little as 0.01% of observed strain. Average strain-to-failure as used herein was measured using an ROR Test. However, unless stated otherwise, strain-to-failure measurements described herein refer to measurements from the ring-on-ring testing, as described in International Publication No. WO2018 / 125676, published on July 5, 2018, entitled “Coated Articles with Optical Coatings Having Residual Compressive Stress,” and incorporated herein by reference in its entirety.

[0110] Suitable glass-ceramic substrates 110 may exhibit an elastic modulus (or Young’s modulus) in the range from about 60 GPa to about 130 GPa. In some instances, the elastic modulus of the glass-ceramic substrate 110 may be in the range from about 70 GPa to about 120 GPa, from about 80 GPa to about 110 GPa, from about 80 GPa to about 100 GPa, from about 80 GPa to about 90 GPa, from about 85 GPa to about 110 GPa, from about 85 GPa toabout 105 GPa, from about 85 GPa to about 100 GPa, from about 85 GPa to about 95 GPa, and all ranges and sub-ranges therebetween (e.g., -103 GPa). In some implementations, the elastic modulus of the glass-ceramic substrate 110 may be greater than 85 GPa, greater than 90 GPa, greater than 95 GPa, or even greater than 100 GPa. In some examples, Young’s modulus may be measured by sonic resonance (ASTM E1875), resonant ultrasound spectroscopy, or nanoindentation using Berkovich indenters. Further, suitable glass-ceramic substrates 110 may exhibit a shear modulus in the range from about 20 GPa to about 60 GPa, from about 25 GPa to about 55 GPa, from about 30 GPa to about 50 GPa, from about 35 GPa to about 50 GPa, and shear modulus ranges and sub-ranges therebetween (e.g., -43 GPa). In some implementations, the glass-ceramic substrate 110 may have a shear modulus of greater than 35 GPa, or even greater than 40 GPa. Further, the glass-ceramic substrates 110 can exhibit a fracture toughness of greater than 0.8 MPa-^m. greater than 0.9 MPa-^m. greater than 1 MPa-^m. or even greater than 1.1 MPa-^m in some instances (e.g., - 1.15 MPa-A / m).

[0111] According to some embodiments, the glass-ceramic substrate 110 can have the following composition: 55-75 mol% SiCh; 0.2-10 mol% AI2O3; 0.2-3 mol% P2O5; 0-5 mol% B2O3; 15-30 mol% Li2O; 0-2 mol% Na2O; 0-2 mol% K2O; 0-2 mol% MgO; 0-2 mol% ZnO; 0.1-10 mol% ZrCh; 0-4 mol% TiCh; 0.01-1.0 mol% SnCh; and 0-2 mol% Y2O3. According to an embodiment, the glass-ceramic substrate 110 can consist essentially of the following composition: 68-72 mol% SiCh; 3-5 mol% AI2O3; 0.6-1.2 mol% P2O5; 0-5 mol% B2O3; 17- 25 mol% Li2O; 0.01-1.7 mol% Na2O; 0.01-0.5 mol% K2O; 1.5-3 mol% ZrO2; 0.01-0.1 mol% SnCh; 0.01-0.1 mol% HfCh: and 0.01-0.5 mol% FC2O3 (exemplary compositions are listed below in Table 1, as measured prior to any ceramming step).

[0112] In one or more embodiments, the glass-ceramic substrate 110 includes one or more glass-ceramic materials and may be strengthened or non-strengthened. In one or more embodiments, the substrates 110 as a glass-ceramic material may comprise one or more crystalline phases such as lithium disilicate (Li2Si20s), lithium metasilicate, petalite (LiAlSi40io), beta quartz, and / or beta spodumene, as potentially combined with residual glass in the structure. In an embodiment, the substrate 110 comprises a disilicate phase. In another implementation, the substrate 110 comprises a disilicate phase and a petalite phase.According to an embodiment, the substrate 110 has a crystallinity of at least 40% by weight. In some implementations, the substrate 110 has a crystallinity of at least about 40%, 45%,50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, or greater (by weight), with the residual as a glass phase. Further, according to some embodiments, each of the crystalline phases of the substrate 110 has an average crystallite size of less than 100 nm, less than 75 nm, less than 50 nm, less than 40 nm, less than 30 nm, and all crystallite sizes within or less than these levels. According to one exemplary embodiment, the substrate 110 comprises lithium disilicate and petalite phases with 40-50 wt.% lithium disilicate (Li2Si20s), 35-45 wt.% petalite (LiAlSi40io), < 2 wt.% of other phases, and the remainder as residual glass (e.g., 10-21 wt.% glass) (exemplary phase assemblages are listed below in Table 2). Unless otherwise noted, all phase assemblage amounts and values are measured through X-ray diffraction (XRD) using a Rietveld analysis.Table - Exemplary glass-ceramic substrate compositionsTable 2 - Phase assemblages of exemplary glass-ceramic substrate compositions (XRD)

[0113] Embodiments of the glass-ceramic substrate 110 employed in the transparent article 100 of the disclosure (see, e.g., FIG. 1) can exhibit a refractive index that is higher than refractive indices of conventional glass substrates or strengthened glass substrates. For example, the refractive index of the substrates 110 can range from about 1.52 to 1.65, fromabout 1.52 to 1.64, from about 1.52 to 1.62, or from about 1.52 to 1.60, and all refractive indices within the foregoing ranges (e.g., as measured at a visible wavelength of 589 nm). As such, conventional optical coatings, which are typically optimized for glass substrates and their refractive index ranges, are not necessarily suitable for use with substrates 110 as comprising glass-ceramic material of the transparent articles 100 of the disclosure. In particular, the layers of the optical film structure 120 between the substrate 110 and the scratch-resistant layer 150 can be modified to achieve low reflectance and low color generated by the transition zone between the glass-ceramic substrate 110 and the scratchresistant layer 150. This layer re-design requirement can also be described as optical impedance matching between the substrate 110 and the scratch-resistant layer 150.

[0114] According to implementations, the glass-ceramic substrate 110 is substantially optically clear, transparent and free from light scattering. In such embodiments, the substrate 110 may exhibit an average light transmittance over the optical wavelength regime from 400- 700 nm or 450-650 nm of about 80% or greater, about 81% or greater, about 82% or greater, about 83% or greater, about 84% or greater, about 85% or greater, about 86% or greater, about 87% or greater, about 88% or greater, about 89% or greater, about 90% or greater, about 91% or greater, about 92% or greater, about 93% or greater, or even about 94% or greater. In some embodiments, these light reflectance and transmittance values may be a total reflectance or total transmittance (taking into account reflectance or transmittance on both primary surfaces 112, 114 of the substrate 110) or may be observed on a single-side of the substrate 110 (i.e., on the primary surface 112 only, without taking into account the opposite surface 114). Unless otherwise specified, the average reflectance or transmittance of the substrate 110 alone is measured at an incident illumination angle of 0 degrees relative to the primary surface 112 (however, such measurements may be provided at incident illumination angles of 45 degrees or 60 degrees).

[0115] In some aspects, the glass-ceramic substrate 110, in addition to being transparent, can also be colored transparent, opaque, colored opaque, translucent, or colored translucent. As used herein “opaque” and “translucent” can mean as follows: opacity is the measure of impenetrability to visible light. An opaque object is neither transparent (allowing all light to pass through) nor translucent (allowing some light to pass through). When light strikes an interface between two substances, in general some may be reflected, some absorbed, somescatered, and the rest transmited. An opaque substance transmits very litle light, and therefore reflects, scaters, or absorbs most of it. Opacity depends on the frequency of the light being considered. For instance, some kinds of glass, while transparent in the visual range, are largely opaque to ultraviolet light. Further, the colored transparent, colored opaque, and colored translucent can be anyone of a variety of colors including, for example, black, white, green, yellow, pink, red, blue, orange, purple, brown, etc.

[0116] Additionally, or alternatively, the physical thickness of the glass-ceramic substrate 110 may vary along one or more of its dimensions for aesthetic and / or functional reasons. For example, the edges of the substrate 110 may be thicker as compared to more central regions of the substrate 110. In other implementations, the edges of the substrate 110 may be thinner as compared to more central regions of the substrate 110. Further, in some embodiments, portions or all of the glass-ceramic substrate 110 (e.g., edge portions) may be non-planar (e.g., beveled, chamfered, curved, etc.). The length, width and physical thickness dimensions of the glass-ceramic substrate 110 may also vary according to the application or use of the article 100.

[0117] The glass-ceramic substrate 110 may be provided using a variety of different processes. For instance, where the substrate 110 includes an amorphous portion or phase such as glass, various forming methods can include float glass processes and down-draw processes such as fusion draw and slot draw.

[0118] Once formed, a glass-ceramic substrate 110 may be strengthened to form a strengthened substrate, e.g., through chemical strengthening by an ion exchange process, thermal tempering, and / or utilizing a mismatch of the coefficient of thermal expansion between portions of the substrate to create compressive stress and central tension regions.

[0119] Where the glass-ceramic substrate 110 is chemically strengthened by an ion exchange process, the ions in the surface layer of the substrate 110 are replaced by - or exchanged with - larger ions having the same valence or oxidation state. Ion exchange processes are typically carried out by immersing a substrate in a molten salt bath containing the larger ions to be exchanged with the smaller ions in the substrate. It will be appreciated by those skilled in the art that parameters for the ion exchange process, including, but not limited to, bath composition and temperature, immersion time, the number of immersions of the substrate 110 in a salt bath (or baths), use of multiple salt baths, additional steps such asannealing, washing, and the like, are generally determined by the composition of the substrate 110 and the desired compressive stress (CS), depth of compressive stress layer (or depth of layer) of the substrate 110 that result from the strengthening operation. By way of example, ion exchange of alkali metal-containing substrates may be achieved by immersion in at least one molten bath containing a salt such as, but not limited to, nitrates, sulfates, and chlorides of the larger alkali metal ion. The temperature of the molten salt bath typically is in a range from about 380 °C up to about 530 °C, while immersion times range from about 15 minutes up to about 40 hours. However, temperatures and immersion times different from those described above may also be used. In some embodiments, the substrate 110 may be subjected to more than one ion-exchange process. For example, a first ion exchange process can be carried out in a sodium-containing bath, exchanging sodium in the bath for lithium in the glass or glass-ceramic substrate 110 to establish a depth of compression (DOC), while subsequently a second ion-exchange process is carried out on the same glass or glass-ceramic substrate in a potassium-containing bath to establish a depth of layer of potassium ions (DOL) and further increase the compressive stress in the substrate 110 near the surface.

[0120] The degree of chemical strengthening achieved by ion exchange may be quantified based on the parameters of central tension (CT), surface CS, depth of compression (DOC) (i.e., the point in the substrate in which the stress state changes from compression to tension), and depth of layer of potassium ions (DOL). Compressive stress (including surface CS) is measured by a surface stress meter (FSM) using commercially available instruments such as the FSM-6000, manufactured by Orihara Industrial Co., Ltd. (Japan). Surface stress measurements rely upon the accurate measurement of the stress optical coefficient (SOC), which is related to the birefringence of the glass-ceramic material. SOC in turn is measured according to Procedure C (Glass Disc Method) described in ASTM standard C770-16, entitled “Standard Test Method for Measurement of Glass Stress-Optical Coefficient,” the contents of which are incorporated herein by reference in their entirety. Refracted near-field (RNF) method or a scattered light polariscope (SCALP) technique may be used to measure the stress profile. When the RNF method is utilized to measure the stress profile, the maximum CT value provided by SCALP is utilized in the RNF method. In particular, the stress profile measured by RNF is force balanced and calibrated to the maximum CT value provided by a SCALP measurement. The RNF method is described in U.S. Patent No.8,854,623, issued October 7, 2014, entitled “Systems and Methods for Measuring a Profile Characteristic of a Glass Sample”, which is incorporated herein by reference in its entirety. In particular, the RNF method includes placing the glass-ceramic article adjacent to a reference block, generating a polarization-switched light beam that is switched between orthogonal polarizations at a rate of between 1 Hz and 50 Hz, measuring an amount of power in the polarization-switched light beam and generating a polarization-switched reference signal, wherein the measured amounts of power in each of the orthogonal polarizations are within 50% of each other. The method further includes transmitting the polarization-switched light beam through the glass sample and reference block for different depths into the glass sample, then relaying the transmitted polarization-switched light beam to a signal photodetector using a relay optical system, with the signal photodetector generating a polarization-switched detector signal. The method also includes dividing the detector signal by the reference signal to form a normalized detector signal and determining the profile characteristic of the glass-ceramic sample from the normalized detector signal. The maximum CT values are measured using a scattered light polariscope (SCALP) technique known in the art.

[0121] In one embodiment of the transparent article 100 (see FIG. 1), a strengthened glassceramic substrate 110 can have a surface CS of 200 MPa or greater, 250 MPa or greater, 300 MPa or greater, or 350 MPa or greater. In another implementation, a strengthened substrate 110 can exhibit a residual surface compressive stress (CS) of from about 200 MPa to about 1200 MPa, from about 200 MPa to about 1000 MPa, from about 200 MPa to about 800 MPa, from about 200 MPa to about 600 MPa, from about 200 MPa to about 500 MPa, from about 200 MPa to about 400 MPa, from about 225 MPa to about 400 MPa, from 250 MPa to about 400 MPa, and all CS sub-ranges and values in the foregoing ranges. The strengthened substrate 110 may have a DOL of from 1 pm to 5 pm, from 1 pm to 10 pm, or from 1 pm to 15 pm and / or a central tension (CT) of 50 MPa or greater, 75 MPa or greater, 100 MPa or greater, 125 MPa or greater (e.g., 80 MPa, 90 MPa, or 100 MPa or greater) but less than 250 MPa (e.g., 200 MPa or less, 175 MPa or less, 150 MPa or less, etc.). In such implementations of the transparent articles 100 with substrates 110 having a CT from about 50 MPa to about 200 MPa or 80 MPa to about 200 MPa, the thickness of the substrate 110 should be limited to about 0.6 mm or less to ensure that the substrate is not frangible. Forimplementations employing thicker substrates, e.g., with a thickness up to 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, or even up to 1.5 mm, the upper limit of CT should be held to levels below 200 MPa to ensure that the substrate is not frangible (e.g., 150 MPa for a thickness of 0.8 mm).

[0122] The depth of compression (DOC) of the glass-ceramic substrate 110 may be from 0. b(thickness (t) of the substrate) to about 0.25«t, for example from about 0. 15«t to about 0.25«t, or from about 0.15«t to about 0.20«t. and all DOC values between the foregoing ranges. For example, the substrate 110 can have a DOC of 20% of the thickness of the substrate, as compared to 15% or less for ion-exchanged glass substrates. In some implementations, the DOC of the substrate 110 can be from about 5 pm to about 150 pm, from about 5 pm to about 125 pm, from about 5 pm to about 100 pm, and all DOC values between the foregoing ranges. In some embodiments, the depths of compression for the substrate materials can range from -8% to -20% of the thickness of the glass-ceramic substrate 110. Note that the foregoing DOC values are as measured from one of the primary surfaces 112 or 114 of the glass-ceramic substrate 110. As such, for a substrate 110 with a thickness of 600 pm, the DOC may be 20% of the thickness of the substrate, -120 pm from each of the primary surfaces 112, 114 of the substrate 110, or 240 pm in total for the entire substrate 110. In one or more specific embodiments, the strengthened substrate 110 can exhibit one or more of the following mechanical properties: a surface CS of from about 200 MPa to about 400 MPa, a DOL of greater than 30 pm, a DOC of from about 0.08«t to about 0.25«t, and a CT from about 80 MPa to about 200 MPa.

[0123] According to embodiments of the disclosure, the glass-ceramic substrate 110 (without the optical film structure 120 disposed thereon for measurement purposes) can exhibit a maximum hardness of 12 GPa or greater, 13 GPa or greater, or 14 GPa or greater (or even greater than 16 GPa in some instances), as measured by a Berkovich Hardness Test over an indentation depth range from 100 nm to about 500 nm in the substrate 110. For example, the glass-ceramic substrate 110 can exhibit a maximum hardness of 12 GPa, 12.5 GPa, 13 GPa, 13.5 GPa, 14 GPa, 14.5 GPa, 15 GPa, 15.5 GPa, 16 GPa, and higher hardness levels, as measured by a Berkovich Hardness Test over an indentation depth range from 100 nm to about 500 nm in the substrate 110. Further, glass-ceramic substrates 110 of the disclosure can exhibit a Vicker’s hardness of greater than 700, or even greater than 800, as measuredusing a 200g load. In addition, substrates 110 of the disclosure can exhibit a Mohs hardness of greater than 6.5, or even greater than 7.

[0124] As noted earlier, the glass-ceramic substrate 110 may be non-strengthened or strengthened, and with a suitable composition to support strengthening. Examples of suitable glass ceramics for the substrate 110 may include a Li2O-A12O3-SiC>2 system (i.e., an LAS system) glass ceramics, MgO-AhCh-SiCh system (i.e., an MAS System) glass ceramics, and / or glass ceramics that include a predominant crystal phase including [3-quartz solid solution, p-spodumene ss, cordierite, and lithium disilicate. Such glass-ceramic substrates as substrate 110 may be strengthened using the chemical strengthening processes disclosed herein. In one or more embodiments, MAS-System glass-ceramic substrates may be strengthened in Li2SC>4 molten salt, whereby an exchange of 2Li+for Mg2+can occur.

[0125] According to some embodiments of the transparent article 100 of the disclosure, the glass-ceramic substrate 110 may be a glass-ceramic material of an LAS system with the following composition: 69-80% SiO2, 5-10% A12O3, 10-15% Li2O, 0.01-1% Na2O, 0.01-1% K2O, 0.1-5% P2O5 and 0.1-9% ZrCh (in wt.%, oxide basis). In some implementations of the transparent article 100 of the disclosure, the substrate 110 may be an LAS system with the following composition: 69-80% SiO2, 5-10% AI2O3, 10-15% Li2O, 0.01-1% Na2O, 0.01-1% K2O, 0.1-5% P2O5 and 0.1-9% ZrCh (in wt.%, oxide basis). According to another embodiment, the substrate 110 may be an LAS system with the following composition: 69- 75% SiO2, 5-10% Al2O3, 10-15% Li2O, 0.05-1% Na2O, 0.1-1% K2O, 1-5% P2O5, 2-9% ZrO2and 0.1-2% CaO (in wt.%, oxide basis). According to a further embodiment, the substrate 110 can have the following composition: 69-72% SiC>2, 5-8% AI2O3, 10-13% Li2O, 0.05- 0.5% Na2O, 0. 1-0.5% K2O, 1.5-4% P2O5, 4-9% ZrO2and 0.5-1.5% CaO (in wt.%, oxide basis). According to some embodiments, the glass-ceramic substrate 110 can have the following LAS system composition: 55-75 mol% SiO2; 0.2-10 mol% AI2O3; 0.2-3 mol% P2O5; 0-5 mol% B2O3; 15-30 mol% Li2O; 0-2 mol% Na2O; 0-2 mol% K2O; 0-2 mol% MgO; 0-2 mol% ZnO; 0.1-10 mol% ZrO2; 0-4 mol% TiO2; 0.01-1.0 mol% SnCh; and 0-2 mol% Y2O3. According to an embodiment, the glass-ceramic substrate 110 can consist essentially of the following LAS system composition: 68-72 mol% SiCh; 3-5 mol% AI2O3; 0.6-1.2 mol% P2O5; 0-5 mol% B2O3; 17-25 mol% Li2O; 0.01-1.7 mol% Na2O; 0.01-0.5 mol% K2O; 1.5-3 mol% ZrO2; 0.01-0.1 mol% SnO2; 0.01-0.1 mol% HfO2; and 0.01-0.5 mol% Pe2O3.More generally, these compositions of the glass-ceramic substrate 110 are advantageous for the transparent articles 100 of the disclosure because they exhibit low haze levels, high transparency, high fracture toughness, and high elastic modulus, and are ion-exchangeable.

[0126] According to embodiments of the transparent article 100, the glass-ceramic substrates 110 as glass-ceramic materials are selected with any of the compositions of the disclosure and further processed to the crystallinity levels of the disclosure to exhibit a combination of high fracture toughness (e.g., greater than 1 MPa-^m) and high elastic modulus (e.g., greater than 100 GPa). These mechanical properties can be derived from the presence of the crystalline phase (e.g., the lithium disilicate phase), which exhibits a relatively high modulus; and the microstructure of the final substrate 110, which includes some residual glass phase. Notably, the residual glass phase (and its alkali-containing composition) ensures that the substrate 110 can be ion-exchange strengthened to a high level of central tension (CT) (e.g., greater than 80 MPa) and compressive stress (CS) (e.g., greater than 200 MPa). Further, the ceramming (i.e., the post-melt processing, heat treatment conditions) can be chosen to minimize the grain size of the substrate 110 such that the grain size is smaller than the wavelength of visible light, thereby ensuring that the substrate 110 and article 100 is transparent or substantially transparent. Ultimately, the composition and processing of the substrate 110 as comprising a glass-ceramic material is advantageously selected to achieve a balance of high fracture toughness, high elastic modulus and optical transparency to ensure that the transparent article 100, as employing these substrates 110 and an optical film structure 120, exhibits this balance of mechanical and optical properties, along with a surprising level of damage resistance.

[0127] The glass-ceramic substrate 110 according to one or more embodiments can have a physical thickness ranging from about 100 pm to about 5 mm in various portions of the substrate 110. Example substrate 110 physical thicknesses range from about 100 pm to about 500 pm (e.g., 100, 200, 300, 400 or 500 pm), from about 500 pm to about 1000 pm (e.g., 500, 600, 700, 800, 900 or 1000 pm), and from about 500 pm to about 1500 pm (e.g., 500, 750, 1000, 1250, or 1500 pm), for example. In some implementations, the substrate 110 may have a physical thickness greater than about 1 mm (e.g., about 2, 3, 4, or 5 mm). In one or more specific embodiments, the substrate 110 may have a physical thickness of 2 mm or less,or less than 1 mm. The substrate 110 may be acid polished or otherwise treated to remove or reduce the effect of surface flaws.

[0128] According to embodiments of the transparent article 100 depicted in FIG. 1, the first primary surface 112 of the glass-ceramic substrate 110 can be configured with a morphology to enhance optical properties of the article. In some implementations, the primary surface 112 of the glass-ceramic substrate 110 can be characterized by a surface roughness (Ra) of less than 2.0 nm, 1.75 nm, 1.5 run, 1.4 nm, 1.3 nm, 1.2 nm, 1.1 nm, 1.0 nm, 0.9 nm, 0.8 nm, or even 0.7 nm. For example, the primary surface 112 of the substrate 110 can have a surface roughness (Ra) of 1.5 nm, 1.4 nm, 1.35 nm, 1.3 nm, 1.25 nm, 1.2 nm, 1.15 nm, 1.1 nm, 1.05 nm, 1 nm, 0.9 nm, 0.8 nm, 0.7 nm, 0.6 nm, 0.5 nm, or any other surface roughness value between or below the foregoing levels. In some implementations, the glassceramic substrate 110 of the transparent article 100 depicted in FIG. 1 can be characterized by a porosity of less than about 30%, less than 27.5%, 25%, 20%, 15%, 10%, or even 5%, as measured within a portion of the substrate 110 from the first primary surface 112 to a depth of 50 nm, 75 nm, or 100 nm. For example, the glass-ceramic substrate 110 can have a porosity of 30%, 27.5%, 25%, 22.5%, 20%, 17.5%, 15%, 12.5%, 10%, 7.5%, 5%, 4%, 3%, 2%, 1%, or any other porosity value between or below the foregoing levels. In some implementations of the transparent article 100 depicted in FIG. 1, the article can exhibit a variation of less than 1.5%, 1.4%, 1.3%, 1.2%, 1.1%, 1%, 0.9%, or even 0.8%, in first-surface reflectance, as measured from 0° to 10° incidence within a range of 450 nm to 700 nm, the variation defined as the difference between the maximum and minimum first-surface reflectance measured in any 100 nm increment within the range. For example, the article 100 can exhibit a variation in first-surface reflectance of 1.4%, 1.3%, 1.2%, 1.1%, 1%, 0.9%, 0.8%, 0.7%, 0.6%, 0.5%, or any other reflectance variation between or below the foregoing levels. Also, according to some implementations, the second primary surface 114 of the glass-ceramic substrate 110 can be characterized by the foregoing surface roughness, porosity, and / or reflectance variation attributes associated with the first primary surface 112.

[0129] With regard to the hardness of the transparent articles 100 depicted in FIG. 1, typically, in nanoindentation measurement methods (such as by using a Berkovich indenter) where the coating is harder than the underlying substrate, the measured hardness may appear to increase initially due to development of the plastic zone at shallow indentation depths (e.g.,less than 25 nm or less than 50 nm) and then increases and reaches a maximum value or plateau at deeper indentation depths (e.g., from 50 nm to about 500 nm or 1000 nm). Thereafter, hardness begins to decrease at even deeper indentation depths due to the effect of the underlying substrate. Where a substrate 110 having a greater hardness compared to the optical film structure 120 is utilized, the same effect can be seen; however, the hardness increases at deeper indentation depths due to the effect of the underlying substrate.

[0130] With further regard to the transparent articles 100 depicted in FIG. 1, the indentation depth range and the hardness values at certain indentation depth ranges can be selected to identify a particular hardness response of the optical film structure 120 and the layers of the outer and inner structures 130a, 130b thereof, described herein, without the effect of the underlying glass-ceramic substrate 110. When measuring hardness of the optical film structure 120 (when disposed on a substrate 110) with a Berkovich indenter, the region of permanent deformation (plastic zone) of a material is associated with the hardness of the material. During indentation, an elastic stress field extends well beyond this region of permanent deformation. As indentation depth increases, the apparent hardness and modulus are influenced by stress field interactions with the underlying substrate 110. The influence of the substrate 110 on hardness occurs at deeper indentation depths (i.e., typically at depths greater than about 10% of the total thickness of the optical film structure 120). Moreover, a further complication is that the hardness response requires a certain minimum load to develop full plasticity during the indentation process. Prior to that certain minimum load, the hardness shows a generally increasing trend.

[0131] At small indentation depths (which also may be characterized as small loads) (e.g., up to about 50 nm) in the optical film structure 120, the apparent hardness of a material appears to increase dramatically versus indentation depth. This small indentation depth regime does not represent a true metric of hardness but, instead, reflects the development of the aforementioned plastic zone, which is related to the finite radius of curvature of the indenter. At intermediate indentation depths, the apparent hardness approaches maximum levels. At deeper indentation depths, the influence of the glass-ceramic substrate 110 becomes more pronounced as the indentation depths increase. Hardness may begin to drop dramatically once the indentation depth exceeds about 30% of the optical coating thickness.

[0132] In one or more embodiments, the transparent article 100, as depicted in FIG. 1, may exhibit a maximum hardness that is greater than about 8 GPa, 9 GPa, 10 GPa, 11 GPa, 12 GPa, 13 GPa, 14 GPa, 15 GPa, or greater than 16 GPa (e.g., 16.5 GPa), as measured from the outer surface 120a of the optical fdm structure 120 by a Berkovich Indenter Hardness Test, which is indicative of high shallow hardness. In one or more embodiments, the transparent article 100, as depicted in FIG. 1, may exhibit a hardness that is greater than about 10 GPa, H GPa, 12 GPa, 12.5 GPa, or greater than 13 GPa (e.g., 13.04 GPa), at an indentation depth of 100 nm, as measured from the outer surface 120a of the optical fdm structure 120 by a Berkovich Indenter Hardness Test, which is indicative of high shallow hardness. In one or more embodiments, the transparent article 100, as depicted in FIG. 1, may exhibit a hardness that is greater than about 12 GPa, 13 GPa, 14 GPa, 14.5 GPa, 15 GPa, or greater than 15.5 GPa (e.g., 15.7 GPa), at an indentation depth of 500 nm, as measured from the outer surface 120a of the optical fdm structure 120 by a Berkovich Indenter Hardness Test, which is indicative of high shallow hardness. In one or more embodiments, the transparent article 100, as depicted in FIG. 1, may exhibit an average hardness that is greater than about 12 GPa, 13 GPa, 14 GPa, 14.5 GPa, 15 GPa, or greater than 15.5 GPa (e.g., 15.6 GPa), at an indentation depth from about 450 to 550 nm, as measured from the outer surface 120a of the optical fdm structure 120 by a Berkovich Indenter Hardness Test, which is indicative of high shallow hardness.

[0133] Referring again to the transparent article 100, as depicted in FIG. 1, the design strategy for these articles of using a combination of high RI layers 130B and medium RI layers 130C in the outer structure 130a of the optical fdm structure 120, as well as minimizing the amount of low RI material in the outer structure 130a, is correlated to achieving these high shallow hardness values. While a certain amount of low RI material may be required to achieve certain low reflectance levels, the amount of low RI material can be reduced by replacing some of the low RI material with medium RI material, which increases the shallow hardness and maximum hardness of the optical fdm structure 120 as well as the overall transparent article 100 with its optical fdm structure 120. The use of medium RI layers 130C in the outer structure 130a also contributes to increasing the maximum hardness of the optical fdm structure 120 while allowing for a lower total thickness of the optical fdm structure 120. In embodiments, the combination of maximum hardness ofgreater than 12 GPa, photopic average reflectance of less than 1%, and 940 nm reflectance of less than 3.5% is achieved using a total optical film structure thickness of less than 2000 nm, which is correlated to the design strategy of using high and medium refractive index layers 13 OB and 130C, respectively, in the outer structure 130a of the optical film structure 120.

[0134] In one or more embodiments of the disclosure, the transparent article 100, as depicted in FIG. 1 with a glass-ceramic substrate 110, exhibits an average failure stress level of 500 MPa or greater, 600 MPa or greater, 700 MPa or greater, 750 MPa or greater, 800 MPa or greater, or even 850 MPa or greater, as measured in an ROR Test with the outer surface 120a of the optical film structure 120 of these articles placed in tension. Essentially, these article-level average failure stress levels are indicative of transparent articles 100 with optical film structures 120 that have not experienced any loss, or have not experienced any substantial loss, in failure strength relative to the strength of their bare glass-ceramic substrates. In some embodiments, the transparent article 100 exhibits an average failure stress level of 500 MPa, 550 MPa, 600 MPa, 650 MPa, 700 MPa, 725 MPa, 750 MPa, 775 MPa, 800 MPa, 825 MPa, 850 MPa, 875 MPa, 900 MPa, 925 MPa, 950 MPa, 975 MPa, 1000 MPa, 1025 MPa, 1050 MPa, 1075 MPa, 1100 MPa, and all average failure stress levels between the foregoing values, as measured in an ROR Test with the outer surface 120a of the optical film structure 120 of the article placed in tension.

[0135] Referring again to the transparent articles 100 (see FIG. 1) with average ROR failure stress levels of 700 MPa or greater, it should be understood that these failure stress levels can be achieved through the control of the composition, arrangement and / or processing of the optical film structures 120 employed in the transparent articles 100. Notably, the composition, arrangement and / or processing of the optical film structures 120 can be adjusted to obtain residual compressive stress levels of at least 600 or at least 700 MPa (e.g., from 600 to 1200 MPa, or from 700 to 1100 MPa) and a maximum elastic modulus of at least 120 GPa, as well as a maximum elastic modulus of less than 200 GPa (e.g., from 120 to 200 GPa, from 140 to 200 GPa, from 140 to 170 GPa, or from 140 to 180 GPa). In some cases, it is useful to quantify the elastic modulus of the optical film structure 120 at a depth equal to 15% of the total thickness of the optical film structure 120 to more accurately compare the modulus of the optical film structure 120 for different thicknesses. Using this metric, the preferred range of elastic modulus at a depth equal to 15% of the total thickness of the optical film structure120 can be adjusted to the range of 120 to 200 GPa, 120 to 180 GPa or 120 to 160 GPa. These mechanical properties of the optical fdm structures 120 correlate to average failure stress levels of 500 MPa or greater, 600 MPa or greater, or 700 MPa or greater in the transparent articles 100 employing these optical fdm structures, as measured in an ROR Test with the outer surface 120a of the optical fdm structure of the article placed in tension.

[0136] With regard to retained strength after impact damage, the transparent article 100 of the disclosure may have a retained strength, after impact damage, of greater than or equal to 250 MPa. The term “retained strength,” as used herein, refers to the strength of a transparent article 100 after damage introduction by an impact force when the article is bent to impart tensile tress. Damage is introduced according to the method described in U.S. Patent Publication No. 2019 / 0072469 Al, the salient portions of which are hereby incorporated by reference. For example, an apparatus for impact testing a transparent article 100 of the disclosure includes a pendulum including a bob attached to a pivot. The term “bob” on a pendulum, as used herein, is a weight suspended from and connected to a pivot by an arm. Thus, the bob is connected to the pivot by an arm. The bob includes a base for receiving a glass article, and the glass article is affixed to the base. The apparatus further includes an impacting object positioned such that when the bob is released from a position at an angle greater than zero from the equilibrium position, the surface of the bob contacts the impacting object. The impacting object includes an abrasive sheet having an abrasive surface to be placed in contact with the outer surface of the transparent article 100. The abrasive sheet may comprise sandpaper, which may have a grit size in the range of 30 grit to 400 grit, or 100 grit to 300 grit, for example 180 grit. Further details of this test method are described in U.S. Patent Publication No. 2024 / 0182356, published on June 6, 2024, the salient portions of which are hereby incorporated by reference.

[0137] For purposes of this disclosure, the impacting object was in the form of a 6 mm diameter disk of 180 grit sandpaper affixed to the apparatus. A transparent article 100 having a thickness of approximately 550.0 pm was affixed to the bob. For each impact, a fresh sandpaper disk was used. Damage on the article 100 was done by pulling the swing of the arm of the apparatus to approximately a 90° angle. After twelve hours or more of the damage introduction, the articles 100 were fractured in four-point bending (4PB) test as defined by ASTM C-158. The damaged transparent article 100 was placed on support rods (supportspan) with the damaged site on the bottom (i.e., on the tension side) and between the load roads (loading span). For purposes of this disclosure, the loading span was 15 mm and the support span was 30 mm. Loading was done at a constant displacement rate of 5 mm / min using a screw-driven testing machine (Instron®, Norwood, Massachusetts, USA) until failure of glass. In one or more embodiments, the retained strength of the transparent articles 100, as measured according to the foregoing impact method, is greater than or equal to 250 MPa, greater than or equal to 300 MPa, greater than or equal to 350 MPa, or even greater than or equal to 400 MPa. In some embodiments the retained strength of the transparent articles 100 is from about 250 MPa to about 400 MPa, from about 250 MPa to about 350 MPa, from about 250 MPa to about 300 MPa, from about 300 MPa to about 400 MPa, from about 300 MPa to about 350 MPa, from about 350 MPa to about 400 MPa, or any combination of these ranges.

[0138] With regard to drop resistance, the transparent articles 100 of the disclosure may also have an average failure height of greater than or equal to 50 cm as measured according to the Drop Test Method on 80 grit sandpaper. The Drop Test Method involves performing face-drop testing on a puck with a glass article attached thereto. The transparent article 100 is attached to the puck with tesa® 61385 double sided adhesive tape to hold the transparent article 100 to the puck during the Drop Test described herein. The transparent article 100 to be tested has a thickness similar or equal to the thickness that will be used in a given handheld consumer electronic device, such as 0.5 mm or 0.6 mm. A puck refers to a structure meant to mimic the size, shape, and weight distribution of a given device, such as a cell phone. Hereinafter, the term “puck,” refers to a structure that has a weight of 200 grams, a length of 133 mm, a width of 68 mm, and a height of 9.4 mm. In embodiments, the puck has the dimensions and weight similar to a handheld electronic device. The drop surface may be sandpaper, such as 80 grit garnet sandpaper, positioned on a steel plate. Further details of this test method are described in U.S. Patent Publication No. 2024 / 0182356, published on June 6, 2024, the salient portions of which are hereby incorporated by reference.

[0139] In one or more embodiments the average failure height of the transparent article 100, when tested according to the Drop Test Method using 80 grit garnet sandpaper, may be greater than or equal to 50 cm, greater than or equal to 75 cm, greater than or equal to 100 cm, greater than or equal to 125 cm, greater than or equal to 150 cm, greater than or equal to175 cm, or even greater than or equal to 200 cm. In some embodiments, the failure height of the transparent articles 100 is from about 50 cm to about 220 cm, such as from about 50 cm to about 200 cm, from about 50 cm to about 150 cm, from about 50 cm to about 100 cm, from about 100 cm to about 220 cm, from about 100 cm to about 200 cm, from about 100 cm to about 150 cm, from about 150 cm to about 220 cm, from about 150 cm to about 200 cm, from about 200 cm to about 220 cm, or any combination of these ranges.

[0140] With further regard to the residual compressive stress and elastic modulus levels (along with hardness levels) of the optical film structure 120, these properties can be controlled through adjustments to the stoichiometry and / or thicknesses of the low RI layers 130A, high RI layers 130B, medium RI layers 130C, capping layer 131 and scratch-resistant layer 150. In embodiments, the residual compressive stress and elastic modulus levels (and hardness levels) exhibited by the optical film structure 120 can be controlled through adjustments to the processing conditions for sputtering the layers of the optical film structure 120, particularly its high RI layers 130B, medium RI layers 130C and scratch-resistant layer 150. In some implementations, for example, a reactive sputtering process can be employed to deposit high RI layers 130B and / or medium RI layers 130C comprising a silicon-containing nitride or a silicon-containing oxynitride. Further, these high RI layers 130B and / or medium RI layers 130C can be deposited by applying power to a silicon sputter target in a reactive gaseous environment containing argon gas (e.g., at flow rates from 50 to 150 seem), nitrogen gas (e.g., at flow rates from 200 to 250 seem) and oxygen gas, with residual compressive stress and elastic modulus levels largely dictated by the selected oxygen gas flow rate. For example, a relatively low oxygen gas flow rate (e.g., 45 seem) can be employed according to the foregoing argon and nitrogen gas flow conditions to produce high RI layers 130B and / or medium RI layers 130C with a SiOxNystoichiometry such that its optical film structure 120 exhibits a residual compressive stress of about 942 MPa, hardness of 17.8 GPa and an elastic modulus of 162.6 GPa. As another example, a relatively high oxygen gas flow rate (e.g., 65 seem) can be employed according to the foregoing argon and nitrogen gas flow conditions to produce high RI layers 130B and / or medium RI layers 130C with a SiOxNystoichiometry such that the optical film structure 120 exhibits a residual compressive stress of about 913 MPa, hardness of 16.4 GPa and an elastic modulus of 148.4 GPa. Accordingly, the stoichiometry of the optical film structure 120, particularly its high RI layers 13 OB, mediumRI layers 130C and scratch resistant layer 150, can be controlled to achieve targeted residual compressive stress and elastic modulus levels, which correlate to the advantageously high average failure stress levels in the transparent articles 100 (e.g., greater than or equal to 600 MPa, 700 MPa, or 800 MPa).

[0141] According to embodiments, the transparent articles 100 depicted in FIG. 1 may exhibit an average two-sided or two-surface (i.e., through both primary surfaces 112, 114 of the glass-ceramic substrate 110) photopic average transmittance, or average visible transmittance, over an optical wavelength regime from 400 to 700 nm, of about 85% or greater, about 88% or greater, about 90% or greater, about 91% or greater, about 92% or greater, about 93% or greater, or even about 94% or greater (e.g., 94.1%) at normal incidence, from 0 to 10 degrees, from 0 to 20 degrees, or even from 0 to 25 degrees. In some embodiments, the transparent articles 100 can exhibit an average two-sided transmittance in the infrared spectrum (e.g., at 940 nm) of about 85% or greater, about 88% or greater, about 90% or greater, about 91% or greater, about 92% or greater, about 93% or greater, or even about 94% (e.g., 91.8% or 94.0% at 940 nm) or greater at normal incidence, from 0 to 10 degrees, from 0 to 20 degrees, or even from 0 to 25 degrees.

[0142] According to embodiments, the transparent articles 100 depicted in FIG. 1 may exhibit an average single-sided or first-surface (i.e., through one of the primary surfaces 112, 114 of the glass-ceramic substrate 110) photopic reflectance, or average reflectance over an optical wavelength regime from 400 to 700 nm through one or both primary surfaces of the substrate 110 (i.e., first-surface or a two-surface reflectance), of less than about 3%, less than about 2.5%, less than about 2%, less than about 1.5%, less than 1%, less than 0.95%, less than 0.9%, or even less than 0.85% (e.g., 0.84% or 0.66%), at normal incidence, near-normal incidence (~8°), or from 0 to 10 degrees. The transparent articles 100 may exhibit an average single -sided or first-surface (i.e., through one of the primary surfaces 112, 114 of the substrate 110) photopic reflectance, or average reflectance over an optical wavelength regime from 400 to 700 nm through one or both primary surfaces of the substrate 110 (i.e., first- surface or a two -surface reflectance), of less than 1%, less than 0.95%, or even less than 0.9%, as measured from 0 to 10 degrees, 0 to 20 degrees, 0 to 30 degrees, or even 0 to 35 degrees angle of incidence.

[0143] According to embodiments, the transparent articles 100 depicted in FIG. 1 may exhibit an average single-sided or first-surface (i.e., through one of the primary surfaces 112, 114 of the glass-ceramic substrate 110) photopic reflectance, or average reflectance over an optical wavelength regime from 400 to 700 nm through one or both primary surfaces of the substrate 110 (i.e., first-surface or a two-surface reflectance), of less than about 3%, less than about 2.5%, less than about 2%, less than about 1.8%, less than 1.6%, or even less than 1.5%, after removal of a portion of the optical film structure 120 from the outer surface 120a to a depth of 18 nm (or less) (e.g., about 1.2%, 1.4% or 1.6% at 18 nm of removal for some examples), at normal incidence, near-normal incidence (~8°), or from 0 to 10 degrees. As such, these implementations of the transparent articles 100 depicted in FIG. 1 are resistant to degradation in optical properties, e.g., reflectance, associated with wear and material removal associated with typical consumer usage of a device incorporating the transparent article.

[0144] According to embodiments, the transparent articles 100 depicted in FIG. 1 may exhibit an average single-sided or first-surface (i.e., through one of the primary surfaces 112, 114 of the substrate 110) reflectance, or average reflectance at an infrared wavelength (e.g., at 940 nm) or infrared wavelength range (e.g., 900-950 nm)), of less than 5%, less than 4.5%, less than 4%, less than 3.5%, less than about 3%, less than about 2.5%, less than about 2%, less than about 1.9%, less than 1.8%, or even less than 1.7% (e.g., 4.14% or 1.65%), at normal incidence, near-normal incidence (~8°), or from 0 to 10 degrees.

[0145] According to some implementations, the transparent articles 100 depicted in FIG. 1 may exhibit a first-surface reflected color with a D65 illuminant from -5 to +5, -4.5 to +4.5, -4 to 32, or -3 to +3, -2 to +2, -5 to +2, or -5 to +1, in a* (e.g., -2.2 to +1.2, and -2.2 to +2.5), and -6 to +6, -5 to +5, -4.5 to +4, -4 to +3, or -3.5 to +3, -6 to +2, or -6 to +1 in b* (e.g., -4.2 to +2.6, and -3 to +3), as measured over all incidence angles from 0 to 90 degrees. For example, the transparent articles 100 can exhibit a first-surface reflected color of -4, -3.5, - 3.0, -2.5, -2.0, -1.5, -1.0, -0.5, 0, +0.5, +1.0, +1.5, +2.0, +2.5, +3.0, +3.5, +4.0, and all values therebetween, in a*, and -6, -5, -4, -3, -2, -1, 0, +1, +2, +3, +4, and all values therebetween, in b*.

[0146] According to some implementations, the transparent articles 100 depicted in FIG. 1 may exhibit a first-surface (i.e., through one of the primary surfaces 112, 114 of the glassceramic substrate 110), reflected color with a D65 illuminant, as given by+ b*2), ofless than 15, less than 12.5, less than 12, less than 10, less than 8.5, less than 8, less than 7, or even less than 6.5, as measured at normal incidence, from 0 to 10 degrees, or over all incidence angles from 0 to 90 degrees. For example, the transparent articles 100 can exhibit a reflected color of less than 15, 14, 13, 12, 11, 10, 9, 8.5, 8, 7, 6.5, 6, 5, 4, 3.75, 3.5, 3.25, 3, 2.75, 2.5, 2.25, 2, 1.9, 1.8, 1.7, 1.75, 1.6, 1.5, 1.4, 1.3, 1.25, 1.2, 1.1, 1, or even lower, as measured at normal incidence, from 0 to 10 degrees, or over all incidence angles from 0 to 90 degrees.

[0147] According to some implementations, the transparent articles 100 depicted in FIG. 1 may exhibit color and reflectance uniformity associated with variations in thickness of the optical fdm structure 120 that results from line-of-sight layer, fdm and optical structure deposition methods together with non-planar portions of the glass-ceramic substrate 110, e.g., as associated with substrates 110 having flat, angled, or curved regions. In particular, these transparent articles 100 can exhibit a color shift in first-surface reflectance and / or two-surface transmittance, as given by ^(a*2+ b*2), of less than 15, less than 12.5, less than 10, less than 8, less than 7, or even less than 6.5, as measured for optical film structure thickness scaling factors that range from 70 to 100%, 75 to 100%, 80 to 100%, 85 to 100%, 90 to 100%, or 95 to 100%. Further, according to some embodiments, the transparent articles 100 can exhibit a color shift in first-surface reflectance and / or two-surface transmittance, as given by ^(a*2+ b*2), of less than 15, less than 12.5, less than 10, less than 8, less than 7, or even less than 6.5, as measured for optical film structure thickness scaling factors that range from 70 to 100%, 75 to 100%, 80 to 100%, 85 to 100%, 90 to 100%, or 95 to 100%, for all incident angles from 0 to 90 degrees or between two angles of incidence, e.g., where the first angle is selected from the range of 0-20 degrees and the second angle is selected from the range of 45-90 degrees.

[0148] According to embodiments, the transparent articles 100 depicted in FIG. 1 may exhibit an average single-sided or first-surface (i.e., through one of the primary surfaces 112, 114 of the glass-ceramic substrate 110) photopic reflectance, or average reflectance over an optical wavelength regime from 400 to 700 nm through one or both primary surfaces of the substrate 110 (i.e., first-surface or a two-surface reflectance), of less than about 3%, less than about 2.5%, less than about 2%, less than about 1.5%, less than 1%, less than 0.95%, or evenless than 0.9%, as measured for optical film structure thickness scaling factors that range from 70 to 100%, 75 to 100%, 80 to 100%, 85 to 100%, 90 to 100%, or 95 to 100%.

[0149] Embodiments of the disclosure also include transparent articles 100 having a range of part surface angles (part surface curvature) that are combined with an optical film structure 120 in which the structure 120 is designed to be robust to thinning of the film structure that occurs from various coating deposition processes (see FIG. 2C, described below). The net result is a transparent article 100 having a range of part surface curvature angles with an optical film structure 120 having controlled hardness, reflectance, color, and color shift with viewing angle over the entire surface of the article 100, including a portion or all of the curved or faceted regions. In addition to absolute levels of hardness, reflectance, and color that meet certain targets, the transparent articles 100 can also exhibit small changes in these values, particularly small changes in visible reflectance and color, when the thickness of the optical film structure 120 is reduced by a scaling factor corresponding to the actual reduction in coating thickness that occurs in an industrially-scalable reactive sputtering process on a manufactured part with surface curvature angles from 0 to 90 degrees. In embodiments, optical film structure thickness scaling factors that range from 70 to 100%, 75 to 100%, 80 to 100%, 85 to 100%, 90 to 100%, or 95 to 100% may correlate to different optical film structure thicknesses created in different regions of a transparent article 100 having a curved or faceted shape with a range of part surface angles from 0 to 10 degrees, 0 to 20 degrees, 0 to 30 degrees, 0 to 40 degrees, 0 to 50 degrees, 0 to 60 degrees, 0 to 70 degrees, 0 to 80 degrees, or 0 to 90 degrees (see FIG. 2C).

[0150] An important piece of understanding to create optimal optical film structure designs for a transparent article 100 (see FIG. 1) with surface curvature, is an understanding of the particular coating process used to form the layers of the optical film structure 120, and the level of line-of-sight coating effects that occur in that process. Some coating deposition processes have no line-of-sight behavior at all, such as atomic layer deposition, where one monolayer of molecules or atoms is deposited at a time. However, this process can be slow (at least as limited by current processing technology) and is typically too expensive for applications involving large substrates or industries that are cost sensitive, such as the consumer electronics and automotive industries. A more cost-effective process for forming the optical film structure 120, reactive sputtering, is readily scalable to large areas and can berelatively low cost. However, the nature of industrial reactive sputtering processes generally includes a deposition that has at least some line-of-sight character, meaning that the surfaces of the article directly facing the sputtering targets will receive more deposited material (resulting in a thicker coating), while surfaces of the article tilted at some angle relative to the sputtering targets (e.g., its curved surfaces) will generally receive less material, resulting in a thinner coating.

[0151] Accordingly, embodiments of the disclosure include transparent articles100 (see FIG. 1) in which the optical fdm structure 120 has been optimized with regard to the tradeoffs between hardness, reflectance, color, and number of coating layers. Adding an arbitrary number of layers to achieve an optical target (e.g., without consideration to hardness or other mechanical properties) in the optical coating will tend to reduce the hardness of the coating to levels below the required range for applications targeting scratch-resistant chemically strengthened glass for consumer electronics, automotive, and touch screen applications (e.g., to a hardness «8 GPa, as measured by Berkovich Indenter Hardness Test at an indentation depth of about 100 nm or greater). In the case of transparent articles 100 having curved surfaces, it can be important to assess how part surface curvature relates to the amount, or scale factor, by which the layers of the optical fdm structure 120 will be reduced or thinned from their target design thicknesses. The target design thickness (or the thickness at 100% scale factor or 1.0 scale factor) is generally the thickness that is coated on the “flat” areas of the article 100, those portions of the article 100 that are closest to directly facing the sputtering targets, or those portions of the article 100 that receive the most material from the sputtering targets. Any part of the article 100 that is curved away from this maximum thickness deposition direction will generally receive less material, resulting in a thinner coating on these curved areas as each of the layers of the optical fdm structure 120 is formed. For optimal optical coating design for the optical fdm structure 120 of embodiments of the articles 100 (see FIG. 1), it can be beneficial to understand the design window in terms of target part curvature, as well as how part curvature corresponds to coating thinning in the deposition process. This can enable optical design of the optical fdm structure 120 in such a way that optimizes, for example, reflectance and color over the target range of part angles and coating thickness variation, without sacrificing too much in terms of the hardness of the coating, number of layers in the coating, or other metrics. Said another way, without anunderstanding of the relevant window of part angles and coating thickness scale factors, one can over-design the coating to include too many layers to achieve a desired set of optical properties, thus sacrificing hardness and scratch resistance.

[0152] Referring generally to the transparent article 100 depicted in FIG. 1, the optical film structures 120 of these articles exhibit high hardness at shallow depths. Further, these optical film structures 120 employ one or more medium RI layers 130C (e.g., n = 1.55 to 1.9, SiOxNy material), sometimes in combination with one or more high RI layers 130B (e.g., n = 1.8 or greater, SiNx), in the outer structure 130a. This strategy tends to enable a minimized use of lower-index materials (e.g., low RI layers 130A) in the optical film structure 120 and the outer structure 130a, which is an important factor in boosting the maximum hardness of the overall optical film structure 120, as well as the hardness measured at shallow indentation depths (as measured from the air-side surface 120a) such as 20 nm, 40 nm, 100 nm, and 125 nm.

[0153] Further, in some embodiments of the transparent article 100 depicted in FIG. 1, the inner structure 130b can comprise a refractive index gradient (not shown in FIG. 1) rather than, for example, a plurality of low and high RI layers 130A, 130B. Thus, in these embodiments, the transparent article 100 may comprise in order: 1) a glass-ceramic substrate 110; 2) a refractive index gradient structure as the inner structure 130b; 3) a scratch resistant layer 150; and 4) an outer structure 130a enabling high shallow hardness. The refractive index gradient may be formed by a compositional gradient. In such embodiments, the composition at or adjacent to the primary surface 112 of the substrate 110 may be tuned to have a refractive index within about 0.05 refractive index units of the refractive index of the substrate 110 itself (e.g., from about 1.45 to 1.55), while the composition at or adjacent to the scratch resistant layer 150 may be tuned to have a refractive index within about 0.1 refractive index units of the refractive index of the scratch resistant layer 150 (e.g., from about 1.65 to 1.95). The thickness of the refractive index gradient region (i.e., as the inner structure 130b) may preferably be in the range from about 100 nm to 500 nm.

[0154] In some embodiments of the transparent article 100 depicted in FIG. 1 with an inner structure 130b comprising a refractive index gradient (gradient not shown in FIG. 1), the gradient is derived from a compositional gradient formed from materials such as Si, Al, N, O, C, and / or combinations thereof. In one or more specific embodiments, the compositiongradient is formed from Si, N and / or O. In one example, the refractive index gradient may include an oxygen-content gradient in which the oxygen content decreases or remains constant along the thickness of the refractive index gradient in the direction from the substrate surface to the scratch resistant layer. In yet another example, the refractive index gradient may include a nitrogen-content gradient in which the nitrogen content increases or remains constant along the thickness of the refractive index gradient in the direction from the substrate surface to the scratch resistant layer. In one or more alternative embodiments, the optical fdm structure 120 may include a density gradient and / or an elastic modulus gradient, in addition to or instead of the refractive index gradient otherwise described herein. In embodiments, an elastic modulus gradient can be utilized to further improve certain mechanical performance aspects of the transparent article 100, such as maintaining or improving retained strength, reducing warp, or reducing delamination.

[0155] Referring generally to the transparent articles 100 detailed above and depicted in exemplary form in FIG. 1, embodiments of these articles employ optical fdm structures 120 that can possess a significant amount of compressive stress, as deposited in the glass-ceramic substrate 110, which can aid in the overall retained strength of the article. On the other hand, the residual compressive stress in the optical film structure 120 can also lead to undesirable warpage to the article 100, necessitating additional processing of the substrate 110 (e.g., asymmetric polishing and material removal) prior to the deposition of the layers that make up the optical film structure 120. That is, some embodiments of the optical film structure 120 are such that some asymmetric removal of material of the substrate 110 (which may be a substrate having surface compressive stress) is required before deposition of the optical film structure 120 to effectively counteract the residual compressive stress of the optical film structure to ensure that the resulting article 100 does not exhibit substantial warpage. In embodiments, the substrate 110 may have a first compressive stress on a first surface and a second compressive stress on a second surface, where the first and second compressive stresses are unequal, or where the integrated compressive stresses over a range of depths adjacent to the first surface and the second surface are unequal. These unequal surface compressive stresses in the substrate 110 can lead to substrate warpage, which can then be balanced (flattened) by deposition of a coating (i.e., an optical film structure 120) with compressive stress on the surface of the substrate 110 having the lower compressive stress. Inembodiments where the first surface of the substrate 110 has a lower compressive stress or a lower integrated compressive stress than the second surface, the coating having a compressive stress would preferably be deposited on the first surface of the substrate 110 to reduce or flatten the warpage of the transparent article 100.

[0156] Without being bound by theory, it is generally understood that reducing the thickness of the optical film structure 120 can reduce the degree of warpage caused by the optical film structure 120, as deposited on the glass-ceramic substrate 110. While some conventional optical film structure designs employ a relatively thick scratch resistant layer (e.g., 2000 nm, SiOxNy), merely reducing the thickness of these scratch resistant layers with the goal of reduced warpage can significantly and undesirably reduce the hardness of the article. Nevertheless, embodiments of the transparent articles 100 of the disclosure (see, e.g., FIG. 1) employ optical film structures 120 with outer structures 130a having multiple high RI layers 130B (e.g., SiNx) and medium RI layers 130C (e.g., SiOxNy) in which the outer structure 130a itself provides a significant hardness response. That is, without being bound by theory, these embodiments are configured with less low RI material in the outer structure 130a and the net result is that the outer structure 130a itself has more influence on the hardness response of the transparent article 100. Accordingly, the scratch resistant layer 150 in these transparent articles 100 plays a less substantial role and, therefore, its thickness is advantageously less influential on the hardness response of the article. Hence, embodiments of these articles 100 (e.g., as shown in FIG. 1) can advantageously employ thinner scratch resistant layers to reduce warpage, while not sacrificing hardness levels and retained strength. In particular, embodiments of the transparent articles 100 of the disclosure (e.g., as shown in FIG. 1) advantageously can be configured to reduce warpage, while retaining an advantageous combination of strength and hardness, through reductions in the thickness of the scratch resistant layer 150 (e.g., to thicknesses from about 100 nm to less than 2000 nm, from about 500 nm to 1500 nm, from about 750 nm to 1250 nm, etc.) employed in the optical film structure 120. That is, any of the transparent articles 100 of the disclosure can benefit from these concepts with a reduction in the stated thickness of its scratch resistant layer 150.

[0157] One benefit of these embodiments is that the reductions to the thickness of the scratch resistant layer 150 means that a lesser amount of material is used in the optical film structure 120, leading to shorter sputter times and associated costs savings and throughputincreases. Another benefit is that decreasing the thickness of the scratch resistant layer 150 can maintain or even slightly improve the retained strength of the article 100. Another benefit is that decreasing the thickness of the scratch resistant layer 150 can provide an improvement on the degree of warp observed in the glass-ceramic substrate 110 after deposition of the optical film structure 120; consequently, the lower degrees of warp necessitate much less processing (e.g., asymmetric polishing) prior to deposition of the optical film structure 120.

[0158] In general, the transparent article 100, as depicted in exemplary form in FIG. 1, exhibits an advantageous combination of distinctive structural features, along with mechanical and optical properties, including one or more of the following: an average photopic reflectance of < 1%, an average infrared (940 nm) reflectance of < 3.5%, low reflectance variation in the visible spectrum, a color shift of less than 15 for all thickness scaling factors from 70-100%, an optical film structure 120 with a total physical thickness of < 2000 nm, and an optical film structure 120 with an outer structure 130a having a total physical thickness from 400-800 nm and / or at least one medium RI layer 130C with a refractive index from 1.55-1.9.

[0159] The transparent articles 100 disclosed herein (e.g., as shown in FIG. 1) may be incorporated into a device article, for example, a device article with a display (or display device articles) (e.g., consumer electronics, including mobile phones, tablets, computers, navigation systems, wearable devices (e.g., watches) and the like), augmented-reality displays, heads-up displays, glasses-based displays, architectural device articles, transportation device articles (e.g., automotive, trains, aircraft, sea craft, etc.), appliance device articles, or any device that benefits from transparency, scratch resistance, abrasion resistance, damage resistance, or a combination thereof. An exemplary device article incorporating any of the articles disclosed herein (e.g., as consistent with the transparent articles 100 depicted in FIG. 1) is shown in FIGS. 2A and 2B. Specifically, FIGS. 2A-2C show a consumer electronic device 200 including a housing 202 having a front 204, a back 206, and side surfaces 208; electrical components (not shown) that are at least partially inside or entirely within the housing and including at least a controller, a memory, and a display 210 at or adjacent to the front surface of the housing; and cover substrate 212 at or over the front surface of the housing such that it is over the display. In some embodiments, the coversubstrate 212 may include any of the transparent articles 100 disclosed herein, including non- planar transparent articles 100 (e.g., as inclusive of non-planar glass-ceramic substrates 110).

[0160] Referring now to FIG. 2C, a perspective view of an alternative embodiment of the consumer electronic device 200 of FIG. 2A is depicted, namely, a consumer electronic device 200a with a display 210a having a non-planar substrate with curved or faceted edges 210b, according to one or more embodiments of the disclosure. In this embodiment, the transparent articles 100 of the disclosure (see FIG. 1) are used in the display 210a, and modified such that they have a range of part surface angles (part surface curvature) that are combined with an optical film structure 120 in which the structure 120 is designed to be robust to thinning of the film structure that occurs from various coating deposition processes.

[0161] According to an implementation, the transparent article 100 depicted in FIG. 1 can be prepared according to a process sequence or method 300 that draws on conventional approaches to substrate processing and optical film structure processing, along with a unique substrate surface preparation approach and an optional asymmetric polishing approach. In one example, the method includes an initial step 301 of providing the glass-ceramic substrate 110. Any of the compositions outlined earlier (see, e.g., Table 1) can be obtained by mixing appropriate precursors, melting them, cooling the melt, and then ceramming the cooled melt (e.g., with a heat treatment to induce some crystallization) according to process approaches understood by those skilled in the field of the disclosure.

[0162] The next step of the method 300 to produce the transparent article 100 depicted in FIG 1 can include a polishing 302 of the first primary surface 112 of the glass-ceramic substrate 110 to a surface roughness (Ra) of less than 1.5 nm. Suitable approaches for this polishing step 302 include a touch-polishing approach, along with other polishing approaches suitable for the following materials and conditions as understood by those skilled in the field of the disclosure. For example, the substrate 110 can be polished in step 302 with a ceria (CcCh) slurry (dso < -3 pm) in which the slurry is disposed on and with a porous urethane polishing pad. More specifically, the polishing step 302 can be conducted with pressures in a range of 0.5-1.5 psi and slurry flow rates from -100 to 1000 mL / min, with a target material removal of -20 pm to 300 pm, -20 pm to 200 pm, -20 pm to 100 pp, -20 pm to 75 pm, or -20 to -50 pm per side of the substrate 110.

[0163] The next step of the method 300 of making the transparent article 100 depicted in FIG. 1 is an immersing step 304 of the glass-ceramic substrate 110 in a molten salt bath to form a compressive stress region in the substrate from each of the primary surfaces 112, 114 to a depth within the glass-ceramic substrate. Appropriate procedures for developing such a compressive stress region (e.g., immersion of the substrate 110 a molten salt bath containing alkali metal oxides) are outlined earlier in this disclosure, and other approaches understood by those skilled in the field of the disclosure may also be employed to generate the compressive stress region in immersing step 304. After the step 304 of forming the compressive stress region in the glass-ceramic substrate 110 (e.g., with the use of a molten salt bath), a cleaning step 306 can be conducted to wash the primary surfaces 112, 114 of the glass-ceramic substrate 110 to remove any excess salts and debris (e.g., with an aqueous bath). For example, the cleaning step 306 performed after the step 304 associated with developing the compressive stress region can be conducted by washing the substrate 110 in a series of rinse tanks (e.g., 2-3 tanks) containing water (e.g., deionized water, city water, etc.) at ambient temperature or slightly elevated temperature below boiling.

[0164] A further step of the method 300 of making the transparent article 100 depicted in FIG. 1 is a polishing step 308 of the first primary surface 112 of the glass-ceramic substrate 110 having the compressive stress region to a surface roughness (Ra) of less than 1.5 nm and a material removal to a depth of 0.1 to 10 pm from the first primary surface. Suitable polishing approaches for step 308 include a touch-polishing approach, along with other polishing approaches suitable for the following materials and conditions as understood by those skilled in the field of the disclosure. For example, the substrate 110 can be polished with a ceria (CeCh) slurry (dso < -3 pm) in step 308 in which the slurry is disposed on the substrate 110 with a porous urethane polishing pad. More specifically, the polishing step 308 can be conducted with pressures in a range of 0.5-1.5 psi and slurry flow rates from -100 to 1000 mL / min, with a target material removal of -0.1 pm to 10 pm, -0. 1 pm to 5 pm, or -1 to -2 pm per side of the substrate 110. For example, a substrate 100 with an Ex. A composition and phase assemblage (see Tables 1 and 2) can be polished according to step 308 using a Super Ce-Rite® 415 slurry on a C74A porous urethane polishing pad at 1.5 psi and 114 mL / min flow, which provides an average material removal of 2.08 pm per side of the substrate.

[0165] According to an embodiment of the method 300 of making the transparent article 100 depicted in FIG. 1, the polishing step 308 can be conducted in an asymmetric fashion to avoid or otherwise minimize any warp associated with the subsequent deposition of the optical fdm structure 120 on one of the primary surfaces 112 or 114 of the substrate 110, e.g., as deposited in step 312 (see below). In particular, deposition of the optical fdm structure 120 on one of the primary surfaces 112 or 114 can result in the development of residual compressive stress, which tends to warp the substrate 110. As such, the polishing step 308 can be conducted to offset such warp that occurs from the subsequent optical fdm structure deposition in step 312 (see below). In general, the polishing step 308 is conducted to remove more material from the primary surface 112 or 114 in which the optical fdm structure 120 is disposed as compared to the other, bare primary surface 112 or 114 in which the optical fdm structure 120 is not present. Moreover, step 308 can be conducted to ensure that a desired final physical thickness of the substrate 110 is obtained and results from the method 300.

[0166] In general, according to these embodiments, the asymmetric polishing step 308 can be designed such that both minimization of substrate warp and a desired final physical thickness of the substrate are met. To do so, step 308 includes a calculation of the appropriate level of material removal to each of the primary surfaces 112, 114 of the substrate 110. As part of this calculation, the amount of material removal on both primary surfaces 112, 114 is determined based on the initial thickness of the substrate 110, elastic properties of the substrate 110 and the ion exchange stress profile developed earlier in steps 304 and 306. According to embodiments in which step 308 is performed in an asymmetric fashion, step 308 can be conducted to estimate the amount of material removal for a two-sided polish (or a one-sided polish) of the substrate 110. Ultimately, the purpose of having a substrate 110 with target level of thickness and warp is such that after a high-stress coating (i.e., the optical film structure 120) is deposited on a pre-warped surface developed from step 308, the coating will deform the warp into a nominally flat substrate as it is deposited during subsequent step 312 (see below). According to embodiments, step 308 can be conducted with calculations for a target warp of 500-1500 pm, 600-1200 pm, 700-1000 pm, or 800 pm - 900 pm and atarget thickness of 380 - 800 pm, 400-700 pm, 450-650 pm, 480-620 pm, 550-620 pm, or 590 pm - 610 pm of the substrate 110.

[0167] An additional step of the method of making the transparent article 100 depicted in FIG. 1 is a step 310 of washing the glass-ceramic substrate 110 in an aqueous bath after the polishing step(s) 308. According to an implementation, the washing step 310 can be conducted in an aqueous bath having a pH of less than 10, e.g., a pH from 7 to 10. For example, the washing step 310 can be conducted at 55°C in an ultrasonic bath with a detergent having a pH from 7 to 10. Other washing approaches, as understood by those skilled in the field of the disclosure, may also be employed with an aqueous bath having a pH of less than 10 to conduct the step 310.

[0168] Further, the method 300 of making the transparent article 100 depicted in FIG. 1 includes a step 312 of disposing an optical film structure 120 on the first primary surface 112 of the glass-ceramic substrate 110 after the washing step 310 to define a transparent article comprising the glass-ceramic substrate and the optical film structure, the optical film structure having an outer surface and a physical thickness of from about 200 nm to 5000 nm. The deposition step 312 can be conducted according to any of the layer deposition approaches (e.g., sputtering) outlined earlier in this disclosure and / or with other approaches as understood by those skilled in the art of the disclosure. Ultimately, the transparent article 100 that results from method 300 is as depicted in FIG. 1, along with any of the foregoing properties and characteristics detailed in this disclosure, including low reflectance variation owing to the careful control of the morphology of the primary surface 112 afforded by the method. It should also be understood that each of the transparent articles 100a and 100b depicted in exemplary form in FIGS. 1A and IB, and described above, can be formed according to the method 300.EXAMPLES

[0169] The following examples describe various features and advantages provided by the disclosure, and are in no way intended to limit the invention and appended claims.

[0170] Comparative Example 1

[0171] According to this comparative example, a transparent article with a glass-ceramic substrate and an optical film structure has been prepared using a conventional processing approach, defined as Comp. Ex. 1A. Notably, the primary surface of the glass-ceramic substrate has not been polished or washed prior to deposition of the optical film structure.Referring now to FIG. 3 A, a pair of scanning electron microscope (SEM) micrographs (100 kX and 50 kX, respectively) of the Comp. Ex. 1A transparent article is provided, specifically the interface between the substrate and optical film structure. As is evident from these figures, voids and pitting is present in the primary surface of the substrate. Further, the voids appear to be partially filled with material from the optical film structure. In addition, the size of the voids appears to be on the order of the thickness of each of the layers of the optical film structure. It is believed that this phenomenon is indicative of undesirable iridescent effects observed when such conventional transparent articles are illuminated in reflection (e.g., with a D65 illuminant).

[0172] Referring now to FIG. 3B, another SEM micrograph of the Comp. Ex. 1A transparent article of FIG. 3 A (magnification not shown, higher magnification than FIG. 3 A) is provided. As is evident from this figure, the pitting and voids observed at the primary surface of the glass-ceramic substrate are on the order of about 50 nm.

[0173] As part of this comparative example, another transparent article with a glassceramic substrate and an optical film structure has been prepared using a conventional processing approach that is materially the same as employed for Comp. Ex. 1A. This conventional transparent article is defined as Comp. Ex. IB. Referring now to FIG. 3C, an atomic force microscopy (AFM) three-dimensional image and two-dimensional AFM image of the primary surface of the glass-ceramic substrate of the Comp. Ex. IB article are provided. As is evident from FIG. 3C, the pitting observed at the primary surface of the glass-ceramic substrate (Comp. Ex. IB) is on the order of about 40 nm or less.

[0174] Comparative Example 2A and Example 2A

[0175] According to this comparative example, a glass-ceramic substrate has been prepared using a comparative processing approach, defined as Comp. Ex. 2A. Notably, the glass-ceramic substrate was prepared according to the method outlined earlier in this disclosure except that the washing step was conducted with a high pH detergent (pH in the 11-12 range). In contrast, a glass-ceramic substrate was prepared using the inventive processing approach detailed in this disclosure, defined as Ex. 2A. Notably, the glassceramic substrate was prepared according to the method outlined earlier in this disclosure, including a washing step conducted with a detergent having a pH of -8.5-9.

[0176] Referring now to FIGS. 4A and 4B, respectively, AFM images of the primary surface of the glass-ceramic substrates of this example (Comp. Ex. 2A and Ex. 2A, respectively) are provided. As is evident from these figures, the primary surface of the glassceramic substrate washed using the high pH detergent (Comp. Ex. 2A) exhibited a substantial degree of pitting. In contrast, the primary surface of the glass-ceramic substrate washed with the more neutral pH (8.5-9) exhibited no apparent pitting or porosity.

[0177] Example 2B and Comparative Example 2B

[0178] This example, and the foregoing examples, show that a porous layer at the primary surfaces of the glass-ceramic substrate, as present after a process step used to form a compressive stress region (e.g., an ion-exchange process), can be removed by a subsequent polishing step, provided that the washing conducted after the polishing step is conducted using a detergent with a pH level below 10 (e.g., pH from 7-10). Conversely, if a higher pH detergent is employed, any porosity removed from a polishing step can be redeveloped by virtue of the washing step conducted at too high of a pH level.

[0179] More specifically, in this example, a glass-ceramic substrate was prepared using an aspect of the inventive processing approach detailed in this disclosure, defined as Ex. 2B. Notably, the glass-ceramic substrate was subjected to an ion-exchange strengthening step (DOC to 0.6t) followed by a touch-polishing step. Further, as part of this example, some of these samples (Ex. 2B) were then subjected to a conventional washing step using a detergent with a pH of 11 at 5% concentration at 65°C for 60 seconds, defined as Comp. Ex. 2B.

[0180] Referring now to FIG. 4C, an AFM image of the primary surface of the glassceramic substrate (Ex. 2B) is provided, both before and after the touch-polishing step. As is evident from this figure, the pitting and surface roughness (Ra) measured by AFM on these samples was reduced significantly with the touch-polishing step, from above 1.5 nm (~1.7 nm) before polishing to less than 1 nm (-0.5-0.7 nm) after polishing.

[0181] Referring now to FIG. 4D, an AFM image of the primary surface of the glassceramic substrate (Comp. Ex. 2B) is provided, i.e., after being subjected to an ion exchange strengthening step, a touch polishing step, and then a washing step with a pH 11 detergent. As is evident from this figure, any reduction in porosity and surface roughness from the touch polishing step was essentially lost by conducting the washing step using a detergent with a pH 11. That is, this figure shows that the surface roughness (Ra) measured by AFM on thesesamples (Comp. Ex. 2B) was not reduced significantly with the washing step, from above 1.5 nm (~1.4-2.16 nm) before washing and polishing to about 1 nm (~0.9-1.0 nm) after polishing and washing with the high pH detergent (pH of 11).

[0182] Example 2C

[0183] In this example, glass-ceramic substrates were prepared using an aspect of the inventive processing approach detailed in this disclosure, defined as Exs. 2C1 and 2C2. Notably, the glass-ceramic substrate was subjected to an ion-exchange strengthening step (DOC to 0.55t) followed by a touch-polishing step. Further, as part of this example, these samples were subjected to a washing step using a detergent with a pH of 7 at 40°C for 180 seconds. Referring now to FIG. 4E, AFM images are provided of two locations on a primary surface of a pair the glass-ceramic substrates of this example (Exs. 2C1, 2C2). As is evident from the figure, very low surface roughness (Ra) levels were obtained using the inventive glass-ceramic substrate approach of the disclosure, -0.4-0.5 nm. Further, no apparent voids, pitting or pores were observed in the AFM images of this figure.

[0184] Examples 3 and 4 - general description

[0185] In this example (Exs. 3 and 4), transparent articles were formed according to the methods of the disclosure and as delineated in Tables 3 and 4. More specifically, the optical film structures of these examples, unless otherwise noted, were formed using a metal-mode, reactive sputtering process in a rotary drum coater, with independent control of sputtering power in the metal deposition and the inductively coupled plasma (ICP) (gas reaction) zones. Reactive gases (e.g., N2 gas and O2 gas) are isolated from the metal target in the ICP (gas reaction) zone. Further, the metal sputtering zone employs only inert gas flow (i.e., Ar gas).

[0186] Optical transmission and reflectance properties were measured on experimental samples prepared according to these examples using an Agilent Cary 5000 UV-Vis-NIR spectrophotometer. Hardness values for the transparent articles reported in the following examples were obtained using the Berkovich Hardness Test method outlined earlier in the disclosure.

[0187] More specifically, the inventive examples (Exs. 3 and 4), as combined with the strengthened glass substrate, exhibit very high shallow hardness and low reflectance in the visible, IR and near-IR spectra, among other mechanical and optical properties, and as exemplary of the transparent articles 100 of the disclosure (see FIG. 1 and correspondingdescription). Further, the inventive examples (Exs. 3 and 4), as comprising glass-ceramic substrates, exhibit, or are otherwise expected to exhibit, high shallow hardness, low reflectance in the visible, IR and near-IR spectra, minimized optical film structure thickness, and low color shift in reflectance, among other optical and mechanical, e.g., retained strength and drop resistance.

[0188] Example 3

[0189] A transparent article including a strengthened glass-ceramic substrate was prepared for this example with the structure delineated below in Table 3 (e.g., as exemplary of the transparent article 100 of FIG. 1, as described above). The glass-ceramic substrate is an ion-exchanged, LAS glass-ceramic material having a thickness of 550 pm and a refractive index of 1.530. Further, the glass-ceramic substrate employs the Ex. B composition detailed earlier in this disclosure (see Tables 1 and 2). After forming, the glass-ceramic substrate was ion-exchange strengthened using a 2-step ion-exchange process. The first ion-exchange step used a molten salt bath of 19.9% KNO3 / 80% NaNCE / 0.1% LiNCE (wt.%) at 500°C for 4 hours. The second ion-exchange step used a molten salt bath of 79.95% KNO3 / 20% NaNCh / 0.05% LiNCh (wt.%) at 500°C for 60 minutes. Notably, the glass-ceramic substrate was subjected to a touch-polishing step after these ion-exchange strengthening steps. Further, as part of this example, these samples were subjected to a washing step using a detergent with a pH of 7-10 at 40°C for 180 seconds. These process conditions resulted in a substrate with low surface roughness (Ra) levels, -0.4-0.8 nm. Further, the layers of the optical film structure were deposited according to vapor deposition conditions set forth in U.S. Patent Application Publication No. 2020 / 0158916, the salient portions of which are incorporated herein by reference.

[0190] Referring again to the transparent article of this example, the layers (e.g., layers 11-19 in Table 3) of the optical film structure above the scratch resistant layer (e.g., layer 10 in Table 3) are configured to achieve high shallow hardness while not negatively affecting the overall thickness (less than 1.6 pm) and optical properties of the article, including reflectance in the visible, IR, and near-IR spectra. As is evident from the optical film structure design of Table 3, medium index layers (SiOxNylayers 11, 13, 15, and 17) are disposed adjacent to high index layers (SiNxlayers 12, 14, 16 and 18), which drive shallow high hardness levels in the article. Similarly, as is evident in Table 3, the total thickness of the low refractive indexlayers (e.g., SiCh layer 19) in the outer structure of the optical film structure above the scratch-resistant layer is minimized to a level that is less than 125 nm, which also helps drive shallow high hardness levels in the article.

[0191] Further, the Ex. 3 design shown below in Table 3 comprises three refractive indices in the upper portion of the AR stack, layers 11-19 located above the thickest hard layer.Overall, the coating design comprises four distinct classes of refractive index, with hardness of the individual layers scaling approximately with refractive index. These four levels in the design include ‘low’ index from 1.45 - 1.50 (e.g., low RI layers 130A), ‘medium’ index from 1.55 - 1.85 (e.g., medium RI layers 130C), ‘medium-high’ index from 1.9-2.0 (e.g., high RI layers 130B), and ‘high’ index from 2.0-2. 1 (e.g., high RI layers 130B).

[0192] Referring again to Table 3 below, the transparent article of this example (Ex. 3) also further incorporates a 1-10 nm thick easy-to-clean silane (fluorinated or non-fluorinated) coating bonded to the top SiCh layer, that has a refractive index nearly identical to the SiCh. For the purposes of the optical modeling results shown below, this silane layer is considered to be part of the top-most SiCh layer 19.able 3 - Ex 3 transparent article design with strengthened glass-ceramic substrateTotal thickness (run): 1517.7Total thickness of outer structure (nm) 532.2Total thickness of low RI material in outer structure (nm) 303.8

[0193] Referring now FIGS. 5 A and 5B, plots are provided of first-surface reflectance and two-surface transmittance vs. wavelength, as measured at a near-normal incident angle of 8° and 0°, respectively, for the transparent article of this example (Ex. 3). Further, FIG. 5C provides a plot of single-sided, reflected color, as measured at incident angles from 0° to 90°, for the transparent article (Ex. 3) of FIGS. 5A and 5B. As is evident from these figures, this design has a 1stsurface photopic average reflectance = 0.84% at 8 degrees AOI, 1stsurface R(940 nm) = 1.65%, and 2-surface T(940 nm) = 94.0%. Further, the first-surface color is well controlled, with -2.2 < a* < 1.2 and -4.2 < b* < 2.6 for all light incidence angles from 0 to 90 degrees.

[0194] In addition, Berkovich hardness and elastic modulus levels were measured on transparent articles of this design (Ex. 3, see Table 3) and are reported as follows: 13.04 GPa at 100 nm depth, 15.70 GPa at 500 nm depth, 15.61 GPa averaged over 450-550 nm depth, maximum 15.70 GPa, and maximum modulus of 149.76 GPa.

[0195] Further, the transparent article of this example is also designed to minimize the reflectance change with removal of the top-most SiC>2 / silane layer, as can happen in real world scratching or surface wear events. Referring now to FIG. 5D, a bar chart is provided that depicts average first-surface reflectance of the transparent article of FIGS. 5 A and 5B, as measured at a near-normal incident angle of 8°, vs. various levels of material removal from the outermost surface of the optical film structure (defined as Ex. 3A). In particular, as is evident from FIG. 5D, the 400-700 nm average reflectance of the design in Table 3 (listed as Ex. 3 A in the chart) remains below 1.2% with top layer material removal in the range of 0- 18 nm. The 400-700 nm average reflectance stays within a range of 0.9-1.2% over this material removal range of 0-18 nm, meaning this average reflectance varies by less than 30% relative to its starting value of -1.15% at zero material removal.

[0196] In addition, the modeled effect of a 50 nm deep porous layer at the primary surface of the glass-ceramic substrate below the optical film structure can be seen in FIG. 5E. FIG. 5E is a plot of first-surface reflectance vs. wavelength, as measured at a near-normal incident angle of 8°, for three comparative transparent articles (Comp. Exs. 3A-3C) and an inventive transparent article (Ex. 3). Here, the Ex. 3 transparent article design is modeled with the presence of a 50 nm porous layer on the primary surface of the glass-ceramic substrate having varying levels of porosity (25%, 20% and 10% porosity, designated Comp. Exs. 3A-3C, respectively), vs. the original design having no porous layer on the substrate (Ex. 3). As illustrated in FIG. 5E, the presence of the porous layer causes variations in reflectance vs. wavelength, which can cause visible changes in color vs. angle (an ‘iridescent’ appearance) under various light sources, especially fluorescent light sources, that can be distracting and objectionable to users. In addition, any spatial variations in this porous layer can cause visible non-uniformities through changing reflectance and color of the coated article.

[0197] As is also evident in FIG. 5E, the transparent article of this design (Ex. 3) can exhibit a variation of less than l%m or even 0.8%, in first-surface reflectance, as measuredfrom 0° to 10° incidence within a range of 450 nm to 700 nm, the variation defined as the difference between the maximum and minimum first-surface reflectance measured in any 100 nm increment within the range. In contrast, the comparative examples with porosity at the primary surface of the glass-ceramic substrate exhibit much higher reflectance variation levels in the same spectra, as measured in any 100 nm increment within the spectra.

[0198] Example 4

[0199] A transparent article including a strengthened glass-ceramic substrate was also prepared for this example with the structure delineated below in Table 4 (e.g., as exemplary of the transparent article 100 of FIG. 1, as described above). The glass-ceramic substrate is an ion-exchanged, LAS glass-ceramic material having a thickness of 550 pm and a refractive index of 1.530. Further, the glass-ceramic substrate employs the Ex. B composition detailed earlier in this disclosure (see Tables 1 and 2). After forming, the glass-ceramic substrate was ion-exchange strengthened using a 2-step ion-exchange process. The first ion-exchange step used a molten salt bath of 19.9% KNO3 / 80% NaNCE / 0.1% LiNCE (wt.%) at 500°C for 4 hours. The second ion-exchange step used a molten salt bath of 79.95% KNO3 / 20% NaNCh / 0.05% LiNCh (wt.%) at 500°C for 60 minutes. Notably, the glass-ceramic substrate was subjected to a touch-polishing step after these ion-exchange strengthening steps. Further, as part of this example, these samples were subjected to a washing step using a detergent with a pH of 7-10 at 40°C for 180 seconds. These process conditions resulted in a substrate with low surface roughness (Ra) levels, -0.4-0.8 nm. Further, the layers of the optical film structure were deposited according to vapor deposition conditions set forth in U.S. Patent Application Publication No. 2020 / 0158916, the salient portions of which are incorporated herein by reference.

[0200] Referring again to the transparent article of this example, the layers (e.g., layers 11-19 in Table 4) of the optical film structure above the scratch resistant layer (e.g., layer 10 in Table 4) are configured to achieve high shallow hardness while not negatively affecting the overall thickness (less than 1.5 pm) and optical properties of the article, including reflectance in the visible, IR, and near-IR spectra. As is evident from the optical film structure design of Table 3, medium index layers (SiOxNylayers 11, 13, 15, and 17) are disposed adjacent to high index layers (SiNxlayers 12, 14, 16 and 18), which drive shallow high hardness levels in the article. Similarly, as is evident in Table 4, the total thickness of the low refractive indexlayers (e.g., SiCh layer 19) in the outer structure of the optical film structure above the scratch-resistant layer is minimized to a level that is less than 125 nm, which also helps drive shallow high hardness levels in the article.

[0201] Further, the Ex. 4 design shown below in Table 4 comprises three refractive indices in the upper portion of the AR stack, layers 11-19 located above the thickest hard layer.Overall, the coating design comprises four distinct classes of refractive index, with hardness of the individual layers scaling approximately with refractive index. These four levels in the design include ‘low’ index from 1.45 - 1.50 (e.g., low RI layers 130A), ‘medium’ index from 1.55 - 1.85 (e.g., medium RI layers 130C), ‘medium-high’ index from 1.9-2.0 (e.g., high RI layers 130B), and ‘high’ index from 2.0-2. 1 (e.g., high RI layers 130B).

[0202] Referring again to Table 4 below, the transparent article of this example (Ex. 4) also further incorporates a 1-10 nm thick easy-to-clean silane (fluorinated or non-fluorinated) coating bonded to the top SiCh layer, that has a refractive index nearly identical to the SiCh. For the purposes of the optical modeling results shown below, this silane layer is considered to be part of the top-most SiCh layer 19.able 4 - Ex 4 transparent article design with strengthened glass-ceramic substrateTotal thickness (run): 1462.4Total thickness of outer structure (nm) 487.0Total thickness of low RI material in outer structure (nm) 271.8

[0203] Referring now FIGS. 6A and 6B, plots are provided of first-surface reflectance and two-surface transmittance vs. wavelength, as measured at a near-normal incident angle of 8° and 0°, respectively, for the transparent article of this example (Ex. 4). Further, FIG. 6C provides a plot of single-sided, reflected color, as measured at incident angles from 0° to 90°, for the transparent article (Ex. 4) of FIGS. 6A and 6B. As is evident from these figures, this design has a 1stsurface photopic average reflectance = 0.66% at 8 degrees AOI, 1stsurface R(940 nm) = 4.14%, and 2-surface T(940 nm) = 91.8%. Further, the first-surface color is well controlled, with -2.2 < a* < 2.5 and -3 < b* < 3 for all light incidence angles from 0 to 90 degrees.

[0204] Further, the transparent article of this example is also designed to minimize the reflectance change with removal of the top-most SiCh / silane layer, as can happen in real world scratching or surface wear events. Referring now to FIG. 6D, a bar chart is provided that depicts average first-surface reflectance of the transparent article of FIGS. 6A and 6B, as measured at a near-normal incident angle of 8°, vs. various levels of material removal from the outermost surface of the optical film structure (defined as Ex. 4A). In particular, as is evident from FIG. 5D, the 400-700 nm average reflectance of the design in Table 4 (listed as Ex. 4A in the chart) remains below 1.6% with top layer material removal in the range of 0- 18 nm. The 400-700 nm average reflectance stays within a range of 0.7-1.5% over this material removal range of 0-18 nm, meaning this average reflectance varies by less than 120% relative to its starting value of -0.7% at zero material removal.

[0205] One skilled in the art will appreciate that the disclosed glass-ceramic substrate can be utilized with different types of coatings including the above exemplary coatings and other coatings with different structures such as, e.g., an optical coatings with an optical film structure having an outer surface and a physical thickness of from about 200 nm to 5000 nm, where the optical film structure comprises a scratch-resistant layer, and a plurality of alternating low refractive index (RI) layers, and high RI layers (does not include the above medium RI layers), where each of the high RI layers comprises a refractive index of greater than 1.80, and each of the low RI layers comprises a refractive index from 1.35 to 1.7 (e.g., see example 5). The transparent article with this exemplary coating (does not include the medium RI layers) would still have the following: (1) a variation of less than 1% in a first- surface reflectance, as measured from 0° to 10° incidence within a range from 450 nm to 700 nm, the variation defined as the difference between the maximum and minimum first-surface reflectance measured in any 100 nm increment within the range; and (2) a first-surface average photopic reflectance of less than 1%, as measured from 0° to 10° incidence, and further wherein the article exhibits a first-surface reflectance of less than 3.5%, as measured at an infrared wavelength of 940 nm from 0° to 10° incidence.

[0206] Example 5

[0207] A transparent article including a strengthened glass-ceramic substrate was also prepared for this example with the structure delineated below in Table 5 (e.g., as exemplary of the transparent article 100a of FIG. 1A, as described above). The glass-ceramic substrateis an ion-exchanged, LAS glass-ceramic material having a thickness of 500 gm and a refractive index of 1.530. Further, the glass-ceramic substrate employs the Ex. B composition detailed earlier in this disclosure (see Tables 1 and 2). After forming, the glassceramic substrate was ion-exchange strengthened using a 2-step ion-exchange process. The first ion-exchange step used a molten salt bath of 19.9% KNO3 / 80% NaNCh / 0.1% LiNCL (wt.%) at 500°C for 4 hours. The second ion-exchange step used a molten salt bath of 79.95% KNO3 / 20% NaNCL / 0.05% LiNCE (wt.%) at 500°C for 60 minutes. Notably, the glassceramic substrate was subjected to a touch-polishing step after these ion-exchange strengthening steps. Further, as part of this example, these samples were subjected to a washing step using a detergent with a pH of 7-10 at 40°C for 180 seconds. These process conditions resulted in a substrate with low surface roughness (Ra) levels, -0.4-0.8 nm. Further, the layers of the optical film structure were deposited according to vapor deposition conditions set forth in U.S. Patent Application Publication No. 2020 / 0158916, the salient portions of which are incorporated herein by reference.

[0208] Referring again to the transparent article of this example, the layers (e.g., layers 11-19 in Table 5) of the optical film structure above the scratch resistant layer (e.g., layer 10 in Table 5) are configured to achieve high hardness and targeted optical properties of the article, including reflectance in the visible, IR, and near-IR spectra. As is evident from the optical film structure design of Table 5, low index layers (SiCh layers 11, 13, 15, 17, and 19) are disposed adjacent to high index layers (SiNxlayers 12, 14, 16 and 18). Further, the Ex. 5 design shown below in Table 5 comprises two refractive indices in the upper portion of the AR stack, layers 11-19 located above the thickest hard layer. Overall, the coating design comprises three distinct classes of refractive index, with hardness of the individual layers scaling approximately with refractive index. These three levels in the design include layers with ‘low’ index values from 1.45 - 1.50 (e.g., low RI layers 130A), a ‘medium-high’ index layer from 1.9-2.0 (e.g., high RI layers 130B), and a ‘high’ index layer from 2.0-2.1 (e.g., high RI layers 130B).

[0209] Also in this example, the scratch resistant layer has a thickness of 1500 nm. Nevertheless, and as is the case with the other Examples 3-4 described above, the thickness of the scratch resistant layer 150 can be adjusted in a range from about 200-5000 nm without substantially changing the optical properties of the article. This allows for optimizing thetrade-off between hardness and cost for different applications. Higher thickness typically leads to higher hardness in these designs, while thicker fdms will typically lead to longer process times, and higher cost.

[0210] Referring again to Table 5 below, the transparent article of this example (Ex. 5) also further incorporates a 1-10 nm thick easy-to-clean silane (fluorinated or non-fluorinated) coating bonded to the top SiO2layer, that has a refractive index nearly identical to the SiO2. For the purposes of the optical modeling results shown below, this silane layer is considered to be part of the top-most SiCh layer 19. able 5 - Ex 5 transparent article design with strengthened glass-ceramic substrateTotal thickness (run): 2329.1Total thickness of outer structure (nm) 543.6Total thickness of low RI material in outer structure (nm) 298.6

[0211] Referring now FIGS. 7A and 7B, plots are provided of first-surface reflectance and two-surface transmittance vs. wavelength, as measured at a near-normal incident angle of 8° and 0°, respectively, for the transparent article of this example (Ex. 5). Further, FIG. 7C provides a plot of single-sided, reflected color, as measured at incident angles from 0° to 90°, for the transparent article (Ex. 5) of FIGS. 7A and 7B. As is evident from these figures, this design has a 1stsurface photopic average reflectance = 0.86% at 8 degrees AOI, 1stsurface R(940 nm) = 1.58%, and 2-surface T(940 nm) = 94.1%. Further, the first-surface color is well controlled, with -2.5 < a* < 1.2 and -4 < b* < 2.5 for all light incidence angles from 0 to 90 degrees.

[0212] Further, the transparent article of this example is also designed to minimize the reflectance change with removal of the top-most SiC>2 / silane layer, as can happen in real world scratching or surface wear events. Referring now to FIG. 7D, a bar chart is provided that depicts average first-surface reflectance of the transparent article of FIGS. 7A and 7B, as measured at a near-normal incident angle of 8°, vs. various levels of material removal from the outermost surface of the optical film structure (defined as Ex. 5A). In particular, as is evident from FIG. 5D, the 400-700 nm average reflectance of the design in Table 5 (listed as Ex. 5 A in the figure) remains below 1.1% with top layer material removal in the range of 0- 18 nm. The 400-700 nm average reflectance stays within a range of 0.75-1.05% over this material removal range of 0-18 nm, meaning this average reflectance varies by less than 30% relative to its starting value of -1.05% at zero material removal.

[0213] Example 6

[0214] In this example, the prior modeling results that demonstrated the benefit of the transparent article processing approach of the disclosure are confirmed experimentally. Four transparent articles were prepared according to the glass-ceramic substrate processing approach of the disclosure, including a wash with a detergent having a pH of about 10 or less, using the optical film structure design of Table 3, as designated Exs. 6A-6D. Referring now to FIGS. 8A and 8B, plots of two-surface reflectance and transmittance, as measured at a near-normal incident angle of 8° and 0°, respectively, are provided for the transparent articles of this example.

[0215] As is evident from FIGS. 8 A and 8B, the porous layers at the primary surface of the glass-ceramic substrate can be eliminated through the inventive polishing and washingsequence, including washing with a detergent having a pH of 10 or lower. As such, a low- ripple reflectance spectra close to the design targets can be achieved in the transparent articles of the disclosure that employ glass-ceramic substrates. Combined with the prior modeling analysis, this indicates that the inventive surface finishing processes enable an optimization of the primary surface of the glass-ceramic surface to a porosity level of < 10% in the first 50 nm or 100 nm of the glass-ceramic substrate.

[0216] Example 7

[0217] In this example, four transparent articles were prepared including a strengthened glass-ceramic substrate with the optical film structures delineated below in Tables 6A, 6B, 6C, and 6D (e.g., as exemplary of the transparent article 100b of FIG. IB, as described above) designated Ex. 7A, 7B, 7C, and 7D respectively. The glass-ceramic substrate is an ion-exchanged, LAS glass-ceramic material having a thickness of 500 pm and a refractive index of 1.530. Further, the glass-ceramic substrate employs the Ex. B composition detailed earlier in this disclosure (see Tables 1 and 2). After forming, the glass-ceramic substrate was ion-exchange strengthened using a 2-step ion-exchange process. The first ion-exchange step used a molten salt bath of 19.9% KNO3 / 80% NaNOs / 0.1% LiNCh (wt.%) at 500°C for 4 hours. The second ion-exchange step used a molten salt bath of 79.95% KNO3 / 20% NaNCh / 0.05% LiNCh (wt.%) at 500°C for 60 minutes. Notably, the glass-ceramic substrate was subjected to a touch-polishing step after these ion-exchange strengthening steps. Further, as part of this example, these samples were subjected to a washing step using a detergent with a pH of 7-10 at 40°C for 180 seconds. These process conditions resulted in a substrate with low surface roughness (Ra) levels, -0.4-0.8 nm. Further, the layers of the optical film structure were deposited according to vapor deposition conditions set forth in U.S. Patent Application Publication No. 2020 / 0158916, the salient portions of which are incorporated herein by reference.

[0218] Referring again to the transparent articles Ex. 7A and 7B of this example, the layers (e.g., layers 17-23 in Tables 6A and 6B) of the optical film structure above the scratch resistant layer (e.g., layer 16 in Tables 6A and 6B) are configured to achieve high hardness and targeted optical properties of the article, including reflectance in the visible, IR, and near- IR spectra. As is evident from the optical film structure design of Tables 6A and 6B, medium index layers (SiOxNylayers 18, 20, and 22) are disposed adjacent to high index layers (SiNxlayers 17, 19 and 21). SiNxLayer 21, being the outermost high index layer, is specifically designed to have a relatively high thickness, which improves the hardness and abrasion resistance of the overall coating structure. SiNxlayer 21 may be the thickest layer above the scratch resistant layer, e.g. the thickest of layers 17-23, and SiNxlayer 21 may further have a thickness greater than lOOnm, greater than 120nm, greater than 140nm, or even greater than 150nm. Further, the Ex. 7A and 7B design shown below in Tables 6A and 6B comprises three refractive indices in the upper portion of the AR stack, layers 17-23 located above the thickest hard layer (i.e., two medium refractive indices, 1.589 and 1.744, and one high refractive index, 2.058). Overall, the coating design comprises three distinct classes of refractive index, with hardness of the individual layers scaling approximately with refractive index. These three levels in the design include Tow’ index from 1.45 - 1.50 (e.g., low RI layers 130A), ‘medium’ index from 1.50 - 1.85 (e.g., medium RI layers 130C), and ‘high’ index from 1.85-2.1 (e.g., high RI layers 130B). The combination of medium RI layers 130C and high RI layers 13 OB serves to maximize the near-surface hardness of the coating structure, improving shallow depth abrasion resistance, which is important for minimizing abrasion visibility.

[0219] Also in this example, the scratch resistant layer has a thickness of 1500 nm. Nevertheless, and as is the case with the other Examples 3-5 described above, the thickness of the scratch resistant layer 150 can be adjusted in a range from about 200-5000 nm without substantially changing the optical properties of the article. This allows for optimizing the trade-off between hardness and cost for different applications. Higher thickness typically leads to higher hardness in these designs, while thicker films will typically lead to longer process times, and higher cost.

[0220] Referring again to Tables 6A, 6B, 6C, and 6D below, the transparent articles of this example (Ex. 7A, 7B, 7C, and 7D) also further incorporate 10-50 nm thick silane (fluorinated or non-fluorinated) or planarization layers comprising a silica-like structure (e.g., as derivedfrom OB-PSS) bonded to the top SiCh layer (i.e., the OB-PSS-containing layer, identified as layer 24; and the OTS-containing layer, identified as layer SF), each of which has a refractive index nearly identical to the SiCh. For the purposes of the optical modeling results shown below, the silane layers in this design are considered to be part of the top-most SiC>2 capping layer 23.

[0221] Referring now FIGS. 9A and 9B, plots are provided of first-surface reflectance and two-surface transmittance vs. wavelength, as measured at a near-normal incident angle of 8° and 0°, respectively, for the transparent article of this example (Ex. 7A and 7B). Further, FIG. 9C provides a plot of single-sided, reflected color, as measured at incident angles from 0° to 90°, for the transparent article (Ex. 7A and 7B) of FIGS. 9A and 9B. As is evident from these figures, this design has a first-surface average reflectance over the entire wavelength range from 425 to 750 nm of less than 1.5% at 8 degrees AOI, first-surface R(940 nm) less than 4.5% (actual value = 4.1%), and two-surface T(940 nm) greater than 90% (actual value = 91.8%, accounting for one coated surface and one uncoated surface of the article). Ex. 7A and Ex. 7B have a first-surface photopic average reflectance of less than 1.5% (actual value = 0.98%) at 8 degrees AOI. Further, the first-surface reflected color is well controlled, with -1 < a* < 0.5 and -4.5 < b* < 2 for all light incidence angles from 0 to 90 degrees.

[0222] Referring again to the transparent articles Ex. 7C and 7D of this example, Ex. 7C and Ex. 7D have many similarities to Ex. 7A and Ex. 7B, as is evident from comparing the optical film structure designs of Tables 6A, 6B, 6C, and 6D. These similarities include the medium index layers (SiOxNylayers 18, 20, and 22) that are disposed adjacent to high index layers (SiNxlayers 17, 19 and 21). SiNxLayer 21, being the outermost high index layer, is specifically designed to have a relatively high thickness, which improves the hardness and abrasion resistance of the overall coating structure. SiNxlayer 21 may be the thickest layer above the scratch resistant layer, e.g. the thickest of layers 17-23, and SiNxlayer 21 may further have a thickness greater than 100 nm, greater than 120nm, greater than 140 nm, or even greater than 150nm. Further, the Ex. 7C and 7D design shown below in Tables 6C and 6D comprises three refractive indices in the upper portion of the AR stack, layers 17-23 located above the thickest hard layer (i.e., two medium refractive indices, 1.589 and 1.744, or 1.631 and 1.744, and one high refractive index, 2.058). Overall, the coating design comprises three distinct classes of refractive index, with hardness of the individual layers scaling approximately with refractive index. These three levels in the design include ‘low’ index from 1.45 - 1.50 (e.g., low RI layers 130A), ‘medium’ index from 1.50 - 1.85 (e.g., medium RI layers 130C), and ‘high’ index from 1.85-2.1 (e.g., high RI layers 130B). The combination of medium RI layers 130C and high RI layers 130B serves to maximize thenear-surface hardness of the coating structure, improving shallow depth abrasion resistance, which is important for minimizing abrasion visibility.

[0223] Ex. 7C and Ex. 7D are distinct from Ex. 7A and Ex. 7B in one or more aspects including the thickness, hardness, and refractive index of the outermost SiOxNylayer (e.g. layer 22). SiOxNylayer 22 has a thickness greater than 50nm or greater than 60 nm (e.g. 69 nm for Ex. 7C and 70 nm for Ex. 7D). The SiOxNylayer of Ex. 7D also has a higher refractive index of 1.631, and a corresponding higher hardness. In addition, the combined thickness of low RI material in the top layer (e.g. layers 23, 24, and SF combined) is minimized to be less than 50nm, less than 40nm, or even less than 35nm (e.g. 30.8nm for the combined sum of layers 23, 24, and SF in Ex. 7C and Ex. 7D). The effect of all of these near- surface layer structure changes is to improve the shallow-depth abrasion resistance and minimize abrasion visibility on the coated articles.

[0224] There is a small increase in reflectance caused by these design changes to Ex. 7C and 7D, together with the benefits of reduced abrasion visibility and reduced color range. Referring now FIGS. 9D, 9E, 9G, and 9H, plots are provided of first-surface reflectance and two-surface transmittance vs. wavelength, as measured at a near-normal incident angle of 8° and 0°, respectively, for the transparent article of Ex. 7C and Ex. 7D. Further, FIG. 9F and FIG. 91 provide a plot of single -sided, reflected color, as measured at incident angles from 0° to 90°, for the transparent articles (Ex. 7C and 7D) of FIGS. 9C and 9F, respectively.

[0225] Ex. 7C has a first-surface average reflectance over the entire wavelength range from 425 to 790 nm of less than 2.1% at 8 degrees AOI, first-surface R(940 nm) less than 4.5% (actual value = 4.04%), and two-surface T(940 nm) greater than 90% (actual value = 91.8%, accounting for one coated surface and one uncoated surface of the article). Ex. 7C has a first-surface photopic average reflectance of less than 2% (actual value = 1.49%) at 8 degrees AOI. Further, the first-surface reflected color is well controlled, with -1 < a* < 0.5 and -3.5 < b* < 1 for all light incidence angles from 0 to 90 degrees.

[0226] Ex. 7D has a first-surface average reflectance over the entire wavelength range from 425 to 810 nm of less than 2.6% at 8 degrees AOI, first-surface R(940 nm) less than 4.5% (actual value = 4.0%), and two-surface T(940 nm) greater than 90% (actual value = 91.9%, accounting for one coated surface and one uncoated surface of the article). Ex. 7C has a first-surface photopic average reflectance of less than 2.5% (actual value = 1.98%) at 8degrees AOI. Further, the first-surface reflected color is well controlled, with -1 < a* < 0.2 and -2.5 < b* < 0.6 for all light incidence angles from 0 to 90 degrees.

[0227] In addition to the benefits of reduced abrasion visibility, increased near-surface hardness, and reduced color range, the slightly higher reflectance of Ex. 7C and Ex. 7D relative to Ex. 7A and Ex. 7B can also have the benefit of reduced visibility of fingerprint oils or other types of contaminants placed on the surface of the coated article, as is common in touch-screen applications. This is due to the reduced reflectance contrast between the soiled areas and clean areas of the coatings, as well as improved optical impedance matching between the fingerprint oils and the coatings with higher reflectance in air (e.g. Ex. 7C and Ex. 7D coatings). Further explanation of these phenomena relating to fingerprints can be found in U.S. Patent No. 10,620,344 B2, issued April 14, 2020, the salient contents of which are hereby incorporated by reference herein.Table 6A - Ex. 7A transparent article design with strengthened glass-ceramic substrateTotal thickness (nm): 2544.1Total thickness of outer structure (nm) 391.8Total thickness of medium and low RI material in outer structure (nm) 148.8Table 6B - Ex. 7B transparent article design with strengthened glass-ceramic substrateTotal thickness (nm): 2544.1Total thickness of outer structure (nm) 369.0Total thickness of medium and low RI material in outer structure (nm) 166.8Table 6C - Ex. 7C transparent article design with strengthened glass-ceramic substrateTotal thickness (nm): 2544.8Total thickness of outer structure (nm) 369.8Total thickness of low and medium RI material in outer structure (nm) 161.5Table 6D - Ex. 7D transparent article design with strengthened glass-ceramic substrateTotal thickness (run): 2544.7Total thickness of outer structure (nm) 369.8Total thickness of low RI material in outer structure (nm) 162

[0228] Example 8

[0229] According to an example of the method 300 that employs a polishing step 308 conducted in an asymmetric fashion, a substrate 110 is selected from a glass-ceramic composition (e.g., the Ex. B composition in Tables 1 and 2). In this example, the target thickness of the substrate 110 is 600 pm ± 10 pm and the target warp is 850 pm ± 50 pm, for the state in which the optical fdm structure 120 has been deposited on the substrate 110. Here, the thickness of the glass-ceramic required prior to asymmetric polishing and the amount of material removal required are unknowns and need to be evaluated. Consider an initial thickness of the substrate 110 in the range of 0.6 mm - 0.64 mm. To evaluate the resulting warp and thickness, the ion-exchange stress profdes in a substrate having the Ex. B glass-ceramic composition of varying thicknesses is evaluated. As the thickness of the glassceramic substrate is increased for a fixed ion-exchange step 304 condition, the stress profile changes and the compressive stress at the surface (CS) generally increases. To approximate the stress profiles at various thicknesses, a simple finite element model (FEA) of the ionexchange step 304 in a glass-ceramic material of Ex. B is conducted, according to FEA principles understood by those skilled in the field of the disclosure. As part of this FEA, the bath conditions employed in step 304 are assumed to be the same, and the substrate having the Ex. B composition has an elastic modulus (E) = 104 GPa, and a Poisson’s ratio (v) = 0. 194. Also, as part of this FEA, the network dilation is assumed to be constant, and the diffusivity of Ex. B is assumed to be approximately 900 ppm / mol % and 4e-7 mm2 / s. The salt bath employed in step 304 has an ion concentration of 4.85 mol%, and an ion exchange duration of 6 hours is employed. The base concentration of ions in the glass-ceramic substrate is 0.2 mol%.

[0230] Stress profiles for glass-ceramic substrate thickness in the range of 0.6 mm - 0.64 mm is obtained (with a simple linear diffusion model), as shown in FIGS. 10A-10B, along with the variation in compressive stress (CS). Knowing the increase in CS as a function of glass-ceramic substrate thickness, the Ex. B glass-ceramic substrate stress profile for the different substrate thicknesses considered in the range of 0.6 mm - 0.64 mm is scaled accordingly, resulting in approximate profiles as shown in FIG. 10C. Based on these stress profiles, the resultant warp and final thickness of the substrate based on asymmetric polishing (e.g., in step 308) is evaluated for each of the five thicknesses considered. As summarizedbelow in Table 7, R1 and R2 are the amounts of material removed on each side of the glassceramic substrate in the range of 1-20 gm, and it is assumed that the R1 side is the side of the substrate in which the optical film structure is later deposited.

[0231] A key result of the analysis in this example is that a specific calculation and sample preparation method must be used in order to achieve both a target warp level and a target final substrate thickness using an asymmetrically polished, ion-exchanged substrate. If the wrong starting substrate thickness is chosen, it is not possible to achieve both the final target substrate warp (which will be compensated by a compressively stressed optical film structure) and final target substrate thickness simultaneously. The preferred process for the polishing step 308 conducted in an asymmetric fashion thus includes: 1) calculation of final desired substrate warp based on target coating thickness and stress; 2) calculation of material removal needed to achieve target warp, based on ion-exchange profiles at different starting thicknesses of the substrate; and 3) identification of starting substrate thickness and asymmetric material removal needed to achieve both target substrate warp and target substrate thickness. Exemplary target values for a smartphone-sized substrate (e.g., length = 120 to 180 mm, width = 50 to 90 mm) substrate, after ion-exchange and asymmetric polishing, but before deposition of the optical film structure, include the following ranges: 1) 0.45-0.65 mm final substrate thickness, and all specific values within that range; 0.5 - 1.5 mm of substrate warp (max height - min height), and all specific values within that range. As is summarized below in Table 7, if an asymmetric polishing step 308 is desired to be conducted on both primary surfaces of the substrate, the most favorable case is employing a starting substrate thickness of 0.62 mm, an R1 material removal of 15 pm, and an R2 material removal of 4 pm, giving a delta of removal of about 11 pm, resulting in a final substrate thickness of 0.601 mm.Table 7 - Summary of Asymmetric Polishing Results from Example 8

[0232] Aspect 1. A transparent article, comprising: a glass-ceramic substrate comprising a first primary surface and a second primary surface, the primary surfaces opposing one another, the first primary surface of the glass-ceramic substrate comprises a surface roughness (Ra) of less than 1.5 nm; and the glass-ceramic substrate further comprises a porosity of less than 25% within a portion of the substrate from the first primary surface to a depth of 100 nm.

[0233] Aspect 2. The transparent article of Aspect 1, wherein the glass-ceramic substrate comprises the following composition:55-75 mol% SiO2;0.2-10 mol% A12O3;0.2-3 mol% P2O5;0-5 mol% B2O3;15-30 mol% Li2O;0-2 mol% Na2O;0-2 mol% K2O;0-2 mol% MgO;0-2 mol% ZnO;0.1-10 mol% ZrO2;0-4 mol% TiCh;0.01-1.0 mol% SnCh; and0-2 mol% Y2O3.

[0234] Aspect 3. The transparent article of Aspect 1, wherein the glass-ceramic substrate consists essentially of the following composition:68-72 mol% SiO2;3-5 mol% Al2O3;0.6- 1.2 mol% P2O5;17-25 mol% Li2O;0.01-1.7 mol% Na2O;0-5 mol% B2O3;0.01-0.5 mol% K2O;1.5-3 mol% ZrO2;0.01-0.1 mol% SnO2;0.01-0.1 mol% HfO2; and0.01-0.5 mol% Fe2O3.

[0235] Aspect 4. The transparent article of Aspect 3, wherein the glass-ceramic substrate further comprises the following phase assemblage:10-21 wt.% glass;40-50 wt.% lithium disilicate (Li2Si20s);35-45 wt.% petalite (LiAlSi40io); and <2 wt.% of other phases.

[0236] Aspect 5. The transparent article of any one Aspects 1-4, further comprising: an optical fdm structure having an outer surface and a physical thickness of from about 200 nm to 5000 nm, the optical film structure disposed on the first primary surface, wherein the optical film structure comprises a scratch-resistant layer, at least one low refractive index (RI) layer, at least one medium RI layer, and at least one high RI layer, wherein the optical film structure further comprises an outer structure and an inner structure, the scratch-resistant layer disposed between the outer and inner structures, the inner structure disposed on the first primary surface, the outer structure comprising a plurality of alternating high and medium RI layers, and the inner structure comprises a plurality of alternating high RI layers and low RI layers, andwherein each medium RI layer comprises a refractive index from 1.55 to 1.9, each of the high RI layers comprises a refractive index of greater than 1.80, and each of the low RI layers comprises a refractive index from 1.35 to 1.7.

[0237] Aspect 6. The transparent article of any one Aspects 1-4, further comprising: an optical fdm structure having an outer surface and a physical thickness of from about 200 nm to 5000 nm, the optical film structure disposed on the first primary surface, wherein the optical film structure comprises a scratch-resistant layer, at least one low refractive index (RI) layer, at least one medium RI layer, and at least one high RI layer, wherein the optical film structure further comprises an outer structure and an inner structure, the scratch-resistant layer disposed between the outer and inner structures, the inner structure disposed on the first primary surface, the outer structure comprising a plurality of alternating high and medium RI layers, and the inner structure comprises a plurality of alternating high RI layers and low RI layers, wherein each medium RI layer comprises a refractive index from 1.55 to 1.9, each of the high RI layers comprises a refractive index of greater than 1.80, and each of the low RI layers comprises a refractive index from 1.35 to 1.7, and further wherein the article exhibits a variation of less than 1% in a first-surface reflectance, as measured from 0° to 10° incidence within a range from 450 nm to 700 nm, the variation defined as the difference between the maximum and minimum first-surface reflectance measured in any 100 nm increment within the range.

[0238] Aspect 7. The transparent article of any one Aspects 1-4, further comprising: an optical film structure having an outer surface and a physical thickness of from about 200 nm to 5000 nm, the optical film structure disposed on the first primary surface, wherein the optical film structure comprises a scratch-resistant layer, and a plurality of alternating low refractive index (RI) layers, and high RI layers, and each of the high RI layers comprises a refractive index of greater than 1.80, and each of the low RI layers comprises a refractive index from 1.35 to 1.7.

[0239] Aspect 8. The transparent article of any one Aspects 1-4, further comprising: an optical film structure having an outer surface and a physical thickness of from about 200 nm to 5000 nm, the optical film structure disposed on the first primary surface,wherein the optical film structure comprises a scratch-resistant layer, at least one low refractive index (RI) layer, at least one medium RI layer, and at least one high RI layer, wherein the optical film structure further comprises an outer structure and an inner structure, the scratch-resistant layer disposed between the outer and inner structures, the inner structure disposed on the first primary surface, and the outer structure comprising a capping layer and a plurality of alternating high and medium RI layers, and further wherein each medium RI layer comprises a refractive index from 1.55 to 1.9, each of the high RI layers comprises a refractive index of greater than 1.80, and each of the low RI layers comprises a refractive index from 1.35 to 1.7.

[0240] Aspect 9. A transparent article includes: a glass-ceramic substrate comprising a first primary surface and a second primary surface, the primary surfaces opposing one another; and an optical film structure having an outer surface and a physical thickness of from about 200 nm to 5000 nm, the optical film structure disposed on the first primary surface. The optical film structure comprises a scratch-resistant layer, at least one low refractive index (RI) layer, at least one medium RI layer, and at least one high RI layer. The optical film structure further comprises an outer structure and an inner structure, the scratchresistant layer disposed between the outer and inner structures, the inner structure disposed on the first primary surface, the outer structure comprising a plurality of alternating high and medium RI layers, and the inner structure comprises a plurality of alternating high RI layers and low RI layers. Further, each medium RI layer comprises a refractive index from 1.55 to 1.9, each of the high RI layers comprises a refractive index of greater than 1.80, and each of the low RI layers comprises a refractive index from 1.35 to 1.7. In addition, the first primary surface of the glass-ceramic substrate comprises a surface roughness (Ra) of less than 1.5 nm.

[0241] Aspect 10. The transparent article of Aspect 9 is provided, wherein the surface roughness (Ra) of the first primary surface of the glass-ceramic substrate is less than 1.0 nm.

[0242] Aspect 11. The transparent article of Aspect 9 is provided, wherein the surface roughness (Ra) of the first primary surface of the glass-ceramic substrate is less than 0.7 nm.

[0243] Aspect 12. The transparent article of any one of Aspects 9-11 is provided, wherein the glass-ceramic substrate further comprises a porosity of less than 25% within a portion of the substrate from the first primary surface to a depth of 100 nm.

[0244] Aspect 13. The transparent article of any one of Aspects 9-11 is provided, wherein the glass-ceramic substrate further comprises a porosity of less than 15% within a portion of the substrate from the first primary surface to a depth of 100 nm.

[0245] Aspect 14. The transparent article of any one of Aspects 9-11 is provided, wherein the glass-ceramic substrate further comprises a porosity of less than 10% within a portion of the substrate from the first primary surface to a depth of 100 nm.

[0246] Aspect 15. The transparent article of any one of Aspects 9-14 is provided, wherein the article exhibits a maximum hardness over all indentation depths from 50-1000 nm of greater than 12 GPa, as measured by a Berkovich Hardness Test at the outer surface of the optical film structure.

[0247] Aspect 16. The transparent article of any one of Aspects 9-15 is provided, wherein the high RI layers and the low RI layers of the plurality of alternating high and low RI layers of the inner structure are SiOxNyand SiO2. respectively, wherein the high RI layers and medium RI layers of the plurality of alternating high RI and medium RI layers of the outer structure are SiNxand SiOxNy, respectively, and wherein the scratch-resistant layer is SiOxNy.

[0248] Aspect 17. The transparent article of Aspect 16 is provided, wherein the physical thickness of the optical film structure is from 1250 nm to 1750 nm, the physical thickness of the scratch-resistant layer is from 500 nm to 1000 nm, and optical film structure has a total of 15 to 23 layers.

[0249] Aspect 18. The transparent article of any one of Aspects 9-17 is provided, wherein the glass-ceramic substrate comprises the following composition:55-75 mol% SiO2;0.2-10 mol% AI2O3;0.2-3 mol% P2O5;0-5 mol% B2O3;15-30 mol% Li2O;0-2 mol% Na2O;0-2 mol% K2O;0-2 mol% MgO;0-2 mol% ZnO;0.1-10 mol% ZrO2;0-4 mol% TiO2;0.01-1.0 mol% SnO2; and0-2 mol% Y2O3.

[0250] Aspect 19. The transparent article of any one of Aspects 9-18 is provided, wherein the glass-ceramic substrate consists essentially of the following composition:68-72 mol% SiO2;3-5 mol% Al2O3;0.6- 1.2 mol% P2O5;17-25 mol% Li2O;0.01-1.7 mol% Na2O;0-5 mol% B2O3;0.01-0.5 mol% K2O;1.5-3 mol% ZrO2;0.01-0.1 mol% SnO2;0.01-0.1 mol% HfO2; and0.01-0.5 mol% Fe2O3.

[0251] Aspect 20. The transparent article of Aspect 19 is provided, wherein the glassceramic substrate further comprises the following phase assemblage:10-21 wt.% glass;40-50 wt.% lithium disilicate (Li2Si20s);35-45 wt.% petalite (LiAlSi40io); and <2 wt.% of other phases.

[0252] Aspect 21. The transparent article of any one of Aspects 9-20 is provided, wherein the glass-ceramic substrate is a non-planar glass-ceramic substrate.

[0253] Aspect 22. The transparent article of any one of Aspects 9-21 is provided, further comprising: a surface modifying layer, wherein the surface modifying layer is disposed on the outer surface of the optical fdm structure.

[0254] Aspect 23. The transparent article of any one of Aspects 9-22 is provided, wherein the article exhibits a variation of less than 1% in a first-surface reflectance, as measured from 0° to 10° incidence within a range from 450 nm to 700 nm, the variationdefined as the difference between the maximum and minimum first-surface reflectance measured in any 100 nm increment within the range.

[0255] Aspect 24. The transparent article of any one of Aspects 9-23 is provided, wherein the article exhibits a first-surface average photopic reflectance of less than 1%, as measured from 0° to 10° incidence, and further wherein the article exhibits a first-surface reflectance of less than 3.5%, as measured at an infrared wavelength of 940 nm from 0° to 10° incidence.

[0256] Aspect 25. A transparent article includes: a glass-ceramic substrate comprising a first primary surface and a second primary surface, the primary surfaces opposing one another; and an optical film structure having an outer surface and a physical thickness of from about 200 nm to 5000 nm, the optical film structure disposed on the first primary surface. The optical film structure comprises a scratch-resistant layer, at least one low refractive index (RI) layer, at least one medium RI layer, and at least one high RI layer. The optical film structure further comprises an outer structure and an inner structure, the scratchresistant layer disposed between the outer and inner structures, the inner structure disposed on the first primary surface, the outer structure comprising a plurality of alternating high and medium RI layers, and the inner structure comprises a plurality of alternating high RI layers and low RI layers. Further, each medium RI layer comprises a refractive index from 1.55 to 1.9, each of the high RI layers comprises a refractive index of greater than 1.80, and each of the low RI layers comprises a refractive index from 1.35 to 1.7. In addition, the article exhibits a variation of less than 1% in a first-surface reflectance, as measured from 0° to 10° incidence within a range from 450 nm to 700 nm, the variation defined as the difference between the maximum and minimum first-surface reflectance measured in any 100 nm increment within the range.

[0257] Aspect 26. The transparent article of Aspect 25 is provided, wherein the variation is less than 0.8%.

[0258] Aspect 27. The transparent article of Aspect 25 or Aspect 26 is provided, wherein the article exhibits a first-surface average photopic reflectance of less than 1%, as measured from 0° to 10° incidence.

[0259] Aspect 28. The transparent article of any one of Aspects 25-27 is provided, wherein the article exhibits an average first-surface reflectance of less than 1.6%, asmeasured from 0° to 10° incidence within a range from 400 nm to 700 nm after removal of a portion of the optical film structure from the outer surface to a depth of 18 nm.

[0260] Aspect 29. The transparent article of any one of Aspects 25-28 is provided, wherein the article exhibits a first-surface reflectance of less than 3.5%, as measured at an infrared wavelength of 940 nm from 0° to 10° incidence.

[0261] Aspect 30. The transparent article of any one of Aspects 25-29 is provided, wherein the high RI layers and the low RI layers of the plurality of alternating high and low RI layers of the inner structure are SiOxNyand SiO2. respectively, wherein the high RI layers and medium RI layers of the plurality of alternating high RI and medium RI layers of the outer structure are SiNxand SiOxNy, respectively, and wherein the scratch-resistant layer is SiOxNy.

[0262] Aspect 31. The transparent article of Aspect 30 is provided, wherein the physical thickness of the optical film structure is from 1250 nm to 1750 nm, the physical thickness of the scratch-resistant layer is from 500 nm to 1000 nm, and optical film structure has a total of 15 to 23 layers.

[0263] Aspect 32. The transparent article of any one of Aspects 25-31 is provided, wherein the glass-ceramic substrate comprises the following composition:55-75 mol% SiO2;0.2-10 mol% A12O3;0.2-3 mol% P2O5;0-5 mol% B2O3;15-30 mol% Li2O;0-2 mol% Na2O;0-2 mol% K2O;0-2 mol% MgO;0-2 mol% ZnO;0.1-10 mol% ZrO2;0-4 mol% TiCh;0.01-1.0 mol% SnCh; and0-2 mol% Y2O3.

[0264] Aspect 33. The transparent article of any one of Aspects 25-31 is provided, wherein the glass-ceramic substrate consists essentially of the following composition:68-72 mol% SiO2;3-5 mol% Al2O3;0.6- 1.2 mol% P2O5;17-25 mol% Li2O;0.01-1.7 mol% Na2O;0-5 mol% B2O3;0.01-0.5 mol% K2O;1.5-3 mol% ZrO2;0.01-0.1 mol% SnO2;0.01-0.1 mol% HfO2; and0.01-0.5 mol% Fe2O3

[0265] Aspect 34. The transparent article of Aspect 33 is provided, wherein the glassceramic substrate further comprises the following phase assemblage:10-21 wt.% glass;35-45 t.% Li2Si2O5;35-45 wt.% petalite; and<2 wt.% of other phases.

[0266] Aspect 35. The transparent article of any one of Aspects 25-34 is provided, wherein the first primary surface of the glass-ceramic substrate comprises a surface roughness (Ra) of less than 1.5 nm.

[0267] Aspect 36. The transparent article of any one of Aspects 25-34 is provided, wherein the first primary surface of the glass-ceramic substrate comprises a surface roughness (Ra) of less than 1.0 nm.

[0268] Aspect 37. The transparent article of any one of Aspects 25-34 is provided, wherein the first primary surface of the glass-ceramic substrate comprises a surface roughness (Ra) of less than 0.7 nm.

[0269] Aspect 38. The transparent article of any one of Aspects 25-37 is provided, wherein the glass-ceramic substrate is a non-planar glass-ceramic substrate.

[0270] Aspect 39. The transparent article of any one of Aspects 25-38 is provided, further comprising: a surface modifying layer, wherein the surface modifying layer is disposed on the outer surface of the optical fdm structure.

[0271] Aspect 40. A method of making a transparent article includes: providing a glassceramic substrate, the glass-ceramic substrate comprising a first primary surface and a second primary surface, the primary surfaces opposing one another; polishing the first primary surface to a surface roughness (Ra) of less than 1.5 nm; immersing the glass-ceramic substrate in a molten salt bath to form a compressive stress region in the substrate from each of the primary surfaces to a depth within the glass-ceramic substrate; polishing the first primary surface of the glass-ceramic substrate having the compressive stress region to a surface roughness (Ra) of less than 1.5 nm and a material removal to a depth of 0.1 to 10 pm from the first primary surface; washing the glass-ceramic substrate in an aqueous bath after the polishing steps; and disposing an optical film structure on the first primary surface of the glass-ceramic substrate after the washing step to define a transparent article comprising the glass-ceramic substrate and the optical film structure, the optical film structure having an outer surface and a physical thickness of from about 200 nm to 5000 nm. The optical film structure comprises a scratch-resistant layer, at least one low refractive index (RI) layer, at least one medium RI layer, and at least one high RI layer. The optical film structure further comprises an outer structure and an inner structure, the scratch-resistant layer disposed between the outer and inner structures, the inner structure disposed on the first primary surface, the outer structure comprising a plurality of alternating high and medium RI layers, and the inner structure comprises a plurality of alternating high RI layers and low RI layers. Each medium RI layer comprises a refractive index from 1.55 to 1.9, each of the high RI layers comprises a refractive index of greater than 1.80, and each of the low RI layers comprises a refractive index from 1.35 to 1.7. Further, the first primary surface of the glassceramic substrate comprises a surface roughness (Ra) of less than 1.5 nm after the washing step.

[0272] Aspect 41. The method of Aspect 40 is provided, wherein the washing the glassceramic substrate step is conducted in an aqueous bath having a pH of less than 10 after the polishing steps.

[0273] Aspect 42. The method of Aspect 40 or Aspect 41 is provided, wherein the glassceramic substrate of the transparent article further comprises a porosity of less than 25% within a portion of the substrate from the first primary surface to a depth of 100 nm.

[0274] Aspect 43. The method of any one of Aspects 40-42 is provided, wherein the transparent article exhibits a variation of less than 1% in a first-surface reflectance, as measured from 0° to 10° incidence within a range from 450 nm to 700 nm, the variation defined as the difference between the maximum and minimum first-surface reflectance measured in any 100 nm increment within the range.

[0275] Aspect 44. The method of any one of Aspects 40-43 is provided, wherein the transparent article exhibits a first-surface average photopic reflectance of less than 1%, as measured from 0° to 10° incidence, and further wherein the article exhibits a first-surface reflectance of less than 3.5%, as measured at an infrared wavelength of 940 nm from 0° to 10° incidence.

[0276] Aspect 45. The method of Aspect 44, wherein the step of polishing the first primary surface of the glass-ceramic substrate having the compressive stress region is conducted such that material is removed from both primary surfaces and more material is removed from the first primary surface than the second primary surface.

[0277] Aspect 46. The method of Aspect 45, wherein the step of polishing the first primary surface of the glass-ceramic substrate having the compressive stress region is further conducted such the article exhibits a warp of 500 to 1500 pm and the physical thickness of the substrate is from 380 to 800 pm, as measured after the step of disposing the optical film structure on the first primary surface of the glass-ceramic substrate.

[0278] Aspect 47. A transparent article, comprising: a glass-ceramic substrate comprising a first primary surface and a second primary surface, the primary surfaces opposing one another, and an optical film structure having an outer surface and a physical thickness of from about 200 nm to 5000 nm, the optical film structure disposed on the first primary surface, wherein the optical film structure comprises a scratch-resistant layer, and a plurality of alternating low refractive index (RI) layers, and high RI layers, each of the high RI layers comprises a refractive index of greater than 1.80, and each of the low RI layers comprises a refractive index from 1.35 to 1.7, and further wherein the first primary surface of the glass-ceramic substrate comprises a surface roughness (Ra) of less than 1.5 nm.

[0279] Aspect 48. The transparent article of Aspect 47, wherein the surface roughness (Ra) of the first primary surface of the glass-ceramic substrate is less than 1.0 nm.

[0280] Aspect 49. The transparent article of Aspect 47, wherein the surface roughness (Ra) of the first primary surface of the glass-ceramic substrate is less than 0.7 nm.

[0281] Aspect 50. The transparent article of any one of Aspects 47-49, wherein the glass-ceramic substrate further comprises a porosity of less than 25% within a portion of the substrate from the first primary surface to a depth of 100 nm.

[0282] Aspect 51. The transparent article of any one of Aspects 47-49, wherein the glass-ceramic substrate further comprises a porosity of less than 15% within a portion of the substrate from the first primary surface to a depth of 100 nm.

[0283] Aspect 52. The transparent article of any one of Aspects 47-49, wherein the glass-ceramic substrate further comprises a porosity of less than 10% within a portion of the substrate from the first primary surface to a depth of 100 nm.

[0284] Aspect 53. The transparent article of any one of Aspects 47-49, wherein the article exhibits a maximum hardness over all indentation depths from 50-1000 nm of greater than 12 GPa, as measured by a Berkovich Hardness Test at the outer surface of the optical film structure.

[0285] Aspect 54. The transparent article of any one of Aspects 47-53, wherein the physical thickness of the optical film structure is from 1250 nm to 1750 nm, the physical thickness of the scratch-resistant layer is from 500 nm to 1000 nm, and optical film structure has a total of 15 to 23 layers.

[0286] Aspect 55. The transparent article of any one of Aspects 47-54, wherein the glass-ceramic substrate comprises the following composition:55-75 mol% SiO2;0.2-10 mol% A12O3;0.2-3 mol% P2O5;0-5 mol% B2O3;15-30 mol% Li2O;0-2 mol% Na2O;0-2 mol% K2O;0-2 mol% MgO;0-2 mol% ZnO;0.1-10 mol% ZrO2;0-4 mol% TiO2;0.01-1.0 mol% SnO2; and0-2 mol% Y2O3.

[0287] Aspect 56. The transparent article of any one of Aspects 47-54, wherein the glass-ceramic substrate consists essentially of the following composition:68-72 mol% SiO2;3-5 mol% Al2O3;0.6- 1.2 mol% P2O5;17-25 mol% Li2O;0.01-1.7 mol% Na2O;0-5 mol% B2O3;0.01-0.5 mol% K2O;1.5-3 mol% ZrO2;0.01-0.1 mol% SnO2;0.01-0.1 mol% HfO2; and0.01-0.5 mol% Fe2O3.

[0288] Aspect 57. The transparent article of Aspect 56, wherein the glass-ceramic substrate further comprises the following phase assemblage:10-21 wt.% glass;40-50 wt.% lithium disilicate (Li2Si20s);35-45 wt.% petalite (LiAlSi40io); and <2 wt.% of other phases.

[0289] Aspect 58. The transparent article of any one of Aspects 47-57, wherein the glass-ceramic substrate is a non-planar glass-ceramic substrate.

[0290] Aspect 59. The transparent article of any one of Aspects 47-58, further comprising: a surface modifying layer, wherein the surface modifying layer is disposed on the outer surface of the optical film structure.

[0291] Aspect 60. The transparent article of any one of Aspects 47-59, wherein the article exhibits a variation of less than 1% in a first-surface reflectance, as measured from 0°to 10° incidence within a range from 450 nm to 700 nm, the variation defined as the difference between the maximum and minimum first-surface reflectance measured in any 100 nm increment within the range.

[0292] Aspect 61. The transparent article of any one of Aspects 47-60, wherein the article exhibits a first-surface average photopic reflectance of less than 1%, as measured from 0° to 10° incidence, and further wherein the article exhibits a first-surface reflectance of less than 3.5%, as measured at an infrared wavelength of 940 nm from 0° to 10° incidence.

[0293] Aspect 62. The transparent article of any one of Aspects 47-61, wherein the optical film structure further comprises an outer structure and an inner structure, the scratchresistant layer disposed between the outer and inner structures, the inner structure disposed on the first primary surface, the outer structure comprising a plurality of alternating low and high RI layers, and the inner structure comprises a plurality of alternating high RI layers and low RI layers.

[0294] Aspect 63. The transparent article of Aspect 62, wherein the high RI layers and the low RI layers of the plurality of alternating high and low RI layers of the inner structure are SiOxNyand SiCh, respectively, wherein the low RI layers and high RI layers of the plurality of alternating low RI and high RI layers of the outer structure are SiNxand SiCh. respectively, and wherein the scratch-resistant layer is SiOxNy.

[0295] Aspect 64. A transparent article, comprising: a glass-ceramic substrate comprising a first primary surface and a second primary surface, the primary surfaces opposing one another; and an optical film structure having an outer surface and a physical thickness of from about 200 nm to 5000 nm, the optical film structure disposed on the first primary surface, wherein the optical film structure comprises a scratch-resistant layer, at least one low refractive index (RI) layer, at least one medium RI layer, and at least one high RI layer, wherein the optical film structure further comprises an outer structure and an inner structure, the scratch-resistant layer disposed between the outer and inner structures, and the inner structure disposed on the first primary surface, the outer structure comprising a capping layer and a plurality of alternating high and medium RI layers, wherein each medium RI layer comprises a refractive index from 1.55 to 1.9, each of the high RI layers comprises a refractive index of greater than 1.80, and each of the low RI layers comprises a refractiveindex from 1.35 to 1.7, and further wherein the first primary surface of the glass-ceramic substrate comprises a surface roughness (Ra) of less than 1.5 nm.

[0296] Aspect 65. The transparent article of Aspect 64, wherein the inner structure comprises a plurality of alternating medium RI layers and low RI layers.

[0297] Aspect 66. The transparent article of Aspect 64 or Aspect 65, wherein the glassceramic substrate comprises an elastic modulus of greater than 85 GPa and a fracture toughness of greater than 0.8 MPa-^m. wherein the optical film structure exhibits a residual compressive stress of greater than or equal to 700 MPa and an elastic modulus of greater than or equal to 140 GPa.

[0298] Aspect 67. The transparent article of any one of Aspects 64-66, wherein the article exhibits an average failure stress of 700 MPa or greater in a ring-on-ring (ROR) test with the outer surface of the optical film structure placed in tension.

[0299] Aspect 68. The transparent article of any one of Aspects 64-67, wherein the transparent article further comprises a top coating, the top coating is disposed on the capping layer, and further wherein the top coating comprises a surface-modifying layer and a planarization layer, the planarization layer disposed on the capping layer.

[0300] Aspect 69. The transparent article of Aspect 68, wherein the planarization layer has a physical thickness of from 10 nm to 60 nm, comprises a silica or a silica-like network comprising Si-O-Si-O bonds, and comprises a molar ratio of hydrogen to silica of about 0.2 or more.

[0301] Aspect 70. The transparent article of Aspect 69, wherein the molar ratio of hydrogen to silica is from about 0.2 to 0.4.

[0302] Aspect 71. The transparent article of any one of Aspects 68-70, wherein the planarization layer comprises a surface roughness (Ra) of from 0.1 nm to 3 nm.

[0303] Aspect 72. The transparent article of any one of Aspects 68-70, wherein a ratio of a surface roughness (Ra) of the planarization layer to the surface roughness (Ra) of the capping layer disposed beneath it is 0.9 or less.

[0304] Aspect 73. The transparent article of any one of Aspects 68-72, wherein the surface-modifying layer comprises octadecyl trimethoxysilane (OTS) and the planarization layer comprises a silica-like structure derived from an octa-isobutyl polyhedral oligomeric silsesquioxane (OB-PSS).

[0305] Aspect 74. The transparent article of any one of Aspects 64-73, wherein the high and medium RI layers of the outer structure are SiNxand SiOxNy, respectively, and the medium RI layers and low RI layers of the inner structure are SiOxNyand SiCh, respectively, wherein the capping layer comprises SiCh, and further wherein the scratch-resistant layer comprises SiOxNy.

[0306] Aspect 75. The transparent article of any one of Aspects 64-74, wherein the glass-ceramic substrate comprises the following composition:55-75 mol% SiO2;0.2-10 mol% AI2O3;0.2-3 mol% P2O5;0-5 mol% B2O3;15-30 mol% Li2O;0-2 mol% Na2O;0-2 mol% K2O;0-2 mol% MgO;0-2 mol% ZnO;0.1-10 mol% ZrO2;0-4 mol% TiCh;0.01-1.0 mol% SnCh; and0-2 mol% Y2O3.

[0307] Aspect 76. The transparent article of any one of Aspects 64-74, wherein the glass-ceramic substrate consists essentially of the following composition:68-72 mol% SiO2;3-5 mol% Al2O3;0.6- 1.2 mol% P2O5;17-25 mol% Li2O;0.01-1.7 mol% Na2O;0-5 mol% B2O3;0.01-0.5 mol% K2O;1.5-3 mol% ZrO2;0.01-0.1 mol% SnO2;0.01-0.1 mol% HfO2; and0.01-0.5 mol% Fe2O3.

[0308] Aspect 77. The transparent article of Aspect 76, wherein the glass-ceramic substrate further comprises the following phase assemblage:10-21 wt.% glass;40-50 wt.% lithium disilicate (Li2Si20s);35-45 wt.% petalite (LiAlSi40io); and<2 wt.% of other phases.

[0309] Although multiple embodiments of the present disclosure have been illustrated in the accompanying Drawings and described in the foregoing Detailed Description, it should be understood that the invention is not limited to the disclosed embodiments, but instead is also capable of numerous rearrangements, modifications, and substitutions without departing from the present disclosure that has been set forth and defined within the following claims.

Claims

What is claimed is:

1. A transparent article, comprising: a glass-ceramic substrate comprising a first primary surface and a second primary surface, the primary surfaces opposing one another; the first primary surface of the glass-ceramic substrate comprises a surface roughness (Ra) of less than 1.5 run; and the glass-ceramic substrate further comprises a porosity of less than 25% within a portion of the substrate from the first primary surface to a depth of 100 nm.

2. The transparent article of claim 1, wherein the glass-ceramic substrate comprises the following composition:55-75 mol% SiO2;0.2-10 mol% A12O3;0.2-3 mol% P2O5;0-5 mol% B2O3;15-30 mol% Li2O;0-2 mol% Na2O;0-2 mol% K2O;0-2 mol% MgO;0-2 mol% ZnO;0.1-10 mol% ZrO2;0-4 mol% TiCh;0.01-1.0 mol% SnCh; and0-2 mol% Y2O3.

3. The transparent article of claim 1, wherein the glass-ceramic substrate consists essentially of the following composition:68-72 mol% SiO2;3-5 mol% Al2O3;0.6- 1.2 mol% P2O5;17-25 mol% Li2O;0.01-1.7 mol% Na2O;0-5 mol% B2O3;0.01-0.5 mol% K2O;1.5-3 mol% ZrO2;0.01-0.1 mol% SnO2;0.01-0.1 mol% HfO2; and0.01-0.5 mol% Fe2O3.

4. The transparent article of claim 3, wherein the glass-ceramic substrate further comprises the following phase assemblage:10-21 wt.% glass;40-50 wt.% lithium disilicate (Li2Si20s);35-45 wt.% petalite (LiAlSi40io); and<2 wt.% of other phases.

5. The transparent article of any one of claims 1-4, further comprising: an optical fdm structure having an outer surface and a physical thickness of from about 200 nm to 5000 nm, the optical film structure disposed on the first primary surface, wherein the optical film structure comprises a scratch-resistant layer, at least one low refractive index (RI) layer, at least one medium RI layer, and at least one high RI layer, wherein the optical film structure further comprises an outer structure and an inner structure, the scratch-resistant layer disposed between the outer and inner structures, the inner structure disposed on the first primary surface, the outer structure comprising a plurality of alternating high and medium RI layers, and the inner structure comprises a plurality of alternating high RI layers and low RI layers, and wherein each medium RI layer comprises a refractive index from 1.55 to 1.9, each of the high RI layers comprises a refractive index of greater than 1.80, and each of the low RI layers comprises a refractive index from 1.35 to 1.7.

6. The transparent article of any one of claims 1-4, further comprising: an optical film structure having an outer surface and a physical thickness of from about 200 nm to 5000 nm, the optical film structure disposed on the first primary surface, wherein the optical film structure comprises a scratch-resistant layer, at least one low refractive index (RI) layer, at least one medium RI layer, and at least one high RI layer, wherein the optical film structure further comprises an outer structure and an inner structure, the scratch-resistant layer disposed between the outer and inner structures, the inner structure disposed on the first primary surface, the outer structure comprising a plurality of alternating high and medium RI layers, and the inner structure comprises a plurality of alternating high RI layers and low RI layers, wherein each medium RI layer comprises a refractive index from 1.55 to 1.9, each of the high RI layers comprises a refractive index of greater than 1.80, and each of the low RI layers comprises a refractive index from 1.35 to 1.7, and further wherein the article exhibits a variation of less than 1% in a first-surface reflectance, as measured from 0° to 10° incidence within a range from 450 nm to 700 nm, the variation defined as the difference between the maximum and minimum first-surface reflectance measured in any 100 nm increment within the range.

7. The transparent article of any one of claims 1-4, further comprising: an optical film structure having an outer surface and a physical thickness of from about 200 nm to 5000 nm, the optical film structure disposed on the first primary surface, wherein the optical film structure comprises a scratch-resistant layer, and a plurality of alternating low refractive index (RI) layers, and high RI layers, and each of the high RI layers comprises a refractive index of greater than 1.80, and each of the low RI layers comprises a refractive index from 1.35 to 1.7.

8. The transparent article of any one of claims 1-4, further comprising: an optical film structure having an outer surface and a physical thickness of from about 200 nm to 5000 nm, the optical film structure disposed on the first primary surface, wherein the optical film structure comprises a scratch-resistant layer, at least one low refractive index (RI) layer, at least one medium RI layer, and at least one high RI layer,I l lwherein the optical film structure further comprises an outer structure and an inner structure, the scratch-resistant layer disposed between the outer and inner structures, the inner structure disposed on the first primary surface, and the outer structure comprising a capping layer and a plurality of alternating high and medium RI layers, and further wherein each medium RI layer comprises a refractive index from 1.55 to 1.9, each of the high RI layers comprises a refractive index of greater than 1.80, and each of the low RI layers comprises a refractive index from 1.35 to 1.7.

9. A transparent article, comprising: a glass-ceramic substrate comprising a first primary surface and a second primary surface, the primary surfaces opposing one another; and an optical film structure having an outer surface and a physical thickness of from about 200 nm to 5000 nm, the optical film structure disposed on the first primary surface, wherein the optical film structure comprises a scratch-resistant layer, at least one low refractive index (RI) layer, at least one medium RI layer, and at least one high RI layer, wherein the optical film structure further comprises an outer structure and an inner structure, the scratch-resistant layer disposed between the outer and inner structures, the inner structure disposed on the first primary surface, the outer structure comprising a plurality of alternating high and medium RI layers, and the inner structure comprises a plurality of alternating high RI layers and low RI layers, wherein each medium RI layer comprises a refractive index from 1.55 to 1.9, each of the high RI layers comprises a refractive index of greater than 1.80, and each of the low RI layers comprises a refractive index from 1.35 to 1.7, and further wherein the first primary surface of the glass-ceramic substrate comprises a surface roughness (Ra) of less than 1.5 nm.

10. The transparent article of claim 9, wherein the surface roughness (Ra) of the first primary surface of the glass-ceramic substrate is less than 1.0 nm.

11. The transparent article of claim 9, wherein the surface roughness (Ra) of the first primary surface of the glass-ceramic substrate is less than 0.7 nm.

12. The transparent article of any one of claims 9-11, wherein the glass-ceramic substrate further comprises a porosity of less than 25% within a portion of the substrate from the first primary surface to a depth of 100 nm.

13. The transparent article of any one of claims 9-11, wherein the glass-ceramic substrate further comprises a porosity of less than 15% within a portion of the substrate from the first primary surface to a depth of 100 nm.

14. The transparent article of any one of claims 9-11, wherein the glass-ceramic substrate further comprises a porosity of less than 10% within a portion of the substrate from the first primary surface to a depth of 100 nm.

15. The transparent article of any one of claims 9-14, wherein the article exhibits a maximum hardness over all indentation depths from 50-1000 nm of greater than 12 GPa, as measured by a Berkovich Hardness Test at the outer surface of the optical film structure.

16. The transparent article of any one of claims 9-15, wherein the high RI layers and the low RI layers of the plurality of alternating high and low RI layers of the inner structure are SiOxNy and SiO2. respectively, wherein the high RI layers and medium RI layers of the plurality of alternating high RI and medium RI layers of the outer structure are SiNxand SiOxNy, respectively, and wherein the scratch-resistant layer is SiOxNy.

17. The transparent article of claim 16, wherein the physical thickness of the optical fdm structure is from 1250 nm to 1750 nm, the physical thickness of the scratch-resistant layer is from 500 nm to 1000 nm, and optical fdm structure has a total of 15 to 23 layers.

18. The transparent article of any one of claims 9-17, wherein the glass-ceramic substrate comprises the following composition:55-75 mol% SiO2;0.2-10 mol% AI2O3;0.2-3 mol% P2O5;0-5 mol% B2O3;15-30 mol% Li2O;0-2 mol%Na2O;0-2 mol% K2O;0-2 mol% MgO;0-2 mol% ZnO;0.1-10 mol% ZrO2;0-4 mol% TiO2;0.01-1.0 mol% SnO2; and0-2 mol%Y2O3.

19. The transparent article of any one of claims 9-18, wherein the glass-ceramic substrate consists essentially of the following composition:68-72 mol% SiO2;3-5 mol% Al2O3;0.6- 1.2 mol% P2O5;17-25 mol% Li2O;0.01-1.7 mol% Na2O;0-5 mol% B2O3;0.01-0.5 mol% K2O;1.5-3 mol% ZrO2;0.01-0.1 mol% SnO2;0.01-0.1 mol% HfO2; and0.01-0.5 mol% Fe2O3.

20. The transparent article of claim 19, wherein the glass-ceramic substrate further comprises the following phase assemblage:10-21 wt.% glass;40-50 wt.% lithium disilicate (Li2Si20s);35-45 wt.% petalite (LiAlSi40io); and<2 wt.% of other phases.

21. The transparent article of any one of claims 9-20, wherein the glass-ceramic substrate is a non-planar glass-ceramic substrate.

22. The transparent article of any one of claims 9-21, further comprising: a surface modifying layer, wherein the surface modifying layer is disposed on the outer surface of the optical fdm structure.

23. The transparent article of any one of claims 9-22, wherein the article exhibits a variation of less than 1% in a first-surface reflectance, as measured from 0° to 10° incidence within a range from 450 nm to 700 nm, the variation defined as the difference between the maximum and minimum first-surface reflectance measured in any 100 nm increment within the range.

24. The transparent article of any one of claims 9-23, wherein the article exhibits a first- surface average photopic reflectance of less than 1%, as measured from 0° to 10° incidence, and further wherein the article exhibits a first-surface reflectance of less than 3.5%, as measured at an infrared wavelength of 940 nm from 0° to 10° incidence.

25. A transparent article, comprising: a glass-ceramic substrate comprising a first primary surface and a second primary surface, the primary surfaces opposing one another; and an optical film structure having an outer surface and a physical thickness of from about 200 nm to 5000 nm, the optical film structure disposed on the first primary surface, wherein the optical film structure comprises a scratch-resistant layer, at least one low refractive index (RI) layer, at least one medium RI layer, and at least one high RI layer, wherein the optical film structure further comprises an outer structure and an inner structure, the scratch-resistant layer disposed between the outer and inner structures, the inner structure disposed on the first primary surface, the outer structure comprising a plurality of alternating high and medium RI layers, and the inner structure comprises a plurality of alternating high RI layers and low RI layers,wherein each medium RI layer comprises a refractive index from 1.55 to 1.9, each of the high RI layers comprises a refractive index of greater than 1.80, and each of the low RI layers comprises a refractive index from 1.35 to 1.7, and further wherein the article exhibits a variation of less than 1% in a first-surface reflectance, as measured from 0° to 10° incidence within a range from 450 nm to 700 nm, the variation defined as the difference between the maximum and minimum first-surface reflectance measured in any 100 nm increment within the range.

26. The transparent article of claim 25, wherein the variation is less than 0.8%.

27. The transparent article of claim 25 or claim 26, wherein the article exhibits a first- surface average photopic reflectance of less than 1%, as measured from 0° to 10° incidence.

28. The transparent article of any one of claims 25-27, wherein the article exhibits an average first-surface reflectance of less than 1.6%, as measured from 0° to 10° incidence within a range from 400 nm to 700 nm after removal of a portion of the optical film structure from the outer surface to a depth of 18 nm.

29. The transparent article of any one of claims 25-28, wherein the article exhibits a first- surface reflectance of less than 3.5%, as measured at an infrared wavelength of 940 nm from 0° to 10° incidence.

30. The transparent article of any one of claims 25-29, wherein the high RI layers and the low RI layers of the plurality of alternating high and low RI layers of the inner structure are SiOxNy and SiCh. respectively, wherein the high RI layers and medium RI layers of the plurality of alternating high RI and medium RI layers of the outer structure are SiNxand SiOxNy, respectively, and wherein the scratch-resistant layer is SiOxNy.

31. The transparent article of claim 30, wherein the physical thickness of the optical film structure is from 1250 nm to 1750 nm, the physical thickness of the scratch-resistant layer is from 500 nm to 1000 nm, and optical film structure has a total of 15 to 23 layers.

32. The transparent article of any one of claims 25-31, wherein the glass-ceramic substrate comprises the following composition:55-75 mol% SiO2;0.2-10 mol% Al2O3;0.2-3 mol% P2O5;0-5 mol% B2O3;15-30 mol% Li2O;0-2 mol%Na2O;0-2 mol% K2O;0-2 mol% MgO;0-2 mol% ZnO;0.1-10 mol% ZrO2;0-4 mol% TiO2;0.01-1.0 mol% SnO2; and0-2 mol%Y2O3.

33. The transparent article of any one of claims 25-31, wherein the glass-ceramic substrate consists essentially of the following composition:68-72 mol% SiO2;3-5 mol% Al2O3;0.6- 1.2 mol% P2O5;17-25 mol% Li2O;0.01-1.7 mol% Na2O;0-5 mol% B2O3;0.01-0.5 mol% K2O;1.5-3 mol% ZrO2;0.01-0.1 mol% SnO2;0.01-0.1 mol% HfO2; and0.01-0.5 mol% Fe2O3.

34. The transparent article of claim 33, wherein the glass-ceramic substrate further comprises the following phase assemblage:10-21 wt.% glass;40-50 wt.% Li2Si20s;35-45 wt.% petalite; and<2 wt.% of other phases.

35. The transparent article of any one of claims 25-34, wherein the first primary surface of the glass-ceramic substrate comprises a surface roughness (Ra) of less than 1.5 run.

36. The transparent article of any one of claims 25-34, wherein the first primary surface of the glass-ceramic substrate comprises a surface roughness (Ra) of less than 1.0 run.

37. The transparent article of any one of claims 25-34, wherein the first primary surface of the glass-ceramic substrate comprises a surface roughness (Ra) of less than 0.7 run.

38. The transparent article of any one of claims 25-37, wherein the glass-ceramic substrate is a non-planar glass-ceramic substrate.

39. The transparent article of any one of claims 25-38, further comprising: a surface modifying layer, wherein the surface modifying layer is disposed on the outer surface of the optical film structure.

40. A method of making a transparent article, comprising: providing a glass-ceramic substrate, the glass-ceramic substrate comprising a first primary surface and a second primary surface, the primary surfaces opposing one another; polishing the first primary surface to a surface roughness (Ra) of less than 1.5 nm; immersing the glass-ceramic substrate in a molten salt bath to form a compressive stress region in the substrate from each of the primary surfaces to a depth within the glassceramic substrate;polishing the first primary surface of the glass-ceramic substrate having the compressive stress region to a surface roughness (Ra) of less than 1.5 nm and a material removal to a depth of 0.1 to 10 pm from the first primary surface; washing the glass-ceramic substrate in an aqueous bath after the polishing steps; and disposing an optical film structure on the first primary surface of the glass-ceramic substrate after the washing step to define a transparent article comprising the glass-ceramic substrate and the optical film structure, the optical film structure having an outer surface and a physical thickness of from about 200 nm to 5000 nm, wherein the optical film structure comprises a scratch-resistant layer, at least one low refractive index (RI) layer, at least one medium RI layer, and at least one high RI layer, wherein the optical film structure further comprises an outer structure and an inner structure, the scratch-resistant layer disposed between the outer and inner structures, the inner structure disposed on the first primary surface, the outer structure comprising a plurality of alternating high and medium RI layers, and the inner structure comprises a plurality of alternating high RI layers and low RI layers, wherein each medium RI layer comprises a refractive index from 1.55 to 1.9, each of the high RI layers comprises a refractive index of greater than 1.80, and each of the low RI layers comprises a refractive index from 1.35 to 1.7, and further wherein the first primary surface of the glass-ceramic substrate comprises a surface roughness (Ra) of less than 1.5 nm after the washing step.

41. The method of claim 40, wherein the washing the glass-ceramic substrate step is conducted in an aqueous bath having a pH of less than 10 after the polishing steps.

42. The method of claim 40 or claim 41, wherein the glass-ceramic substrate of the transparent article further comprises a porosity of less than 25% within a portion of the substrate from the first primary surface to a depth of 100 nm.

43. The method of any one of claims 40-42, wherein the transparent article exhibits a variation of less than 1% in a first-surface reflectance, as measured from 0° to 10° incidence within a range from 450 nm to 700 nm, the variation defined as the difference between themaximum and minimum first-surface reflectance measured in any 100 nm increment within the range.

44. The method of any one of claims 40-43, wherein the transparent article exhibits a first-surface average photopic reflectance of less than 1%, as measured from 0° to 10° incidence, and further wherein the article exhibits a first-surface reflectance of less than 3.5%, as measured at an infrared wavelength of 940 nm from 0° to 10° incidence.

45. The method of claim 44, wherein the step of polishing the first primary surface of the glass-ceramic substrate having the compressive stress region is conducted such that material is removed from both primary surfaces and more material is removed from the first primary surface than the second primary surface.

46. The method of claim 45, wherein the step of polishing the first primary surface of the glass-ceramic substrate having the compressive stress region is further conducted such the article exhibits a warp of 500 to 1500 pm and the physical thickness of the substrate is from 380 to 800 pm, as measured after the step of disposing the optical film structure on the first primary surface of the glass-ceramic substrate.

47. A transparent article, comprising: a glass-ceramic substrate comprising a first primary surface and a second primary surface, the primary surfaces opposing one another, and an optical film structure having an outer surface and a physical thickness of from about 200 nm to 5000 nm, the optical film structure disposed on the first primary surface, wherein the optical film structure comprises a scratch-resistant layer, and a plurality of alternating low refractive index (RI) layers, and high RI layers, each of the high RI layers comprises a refractive index of greater than 1.80, and each of the low RI layers comprises a refractive index from 1.35 to 1.7, and further wherein the first primary surface of the glass-ceramic substrate comprises a surface roughness (Ra) of less than 1.5 nm.

48. The transparent article of claim 47, wherein the surface roughness (Ra) of the first primary surface of the glass-ceramic substrate is less than 1.0 nm.

49. The transparent article of claim 47, wherein the surface roughness (Ra) of the first primary surface of the glass-ceramic substrate is less than 0.7 nm.

50. The transparent article of any one of claims 47-49, wherein the glass-ceramic substrate further comprises a porosity of less than 25% within a portion of the substrate from the first primary surface to a depth of 100 nm.

51. The transparent article of any one of claims 47-49, wherein the glass-ceramic substrate further comprises a porosity of less than 15% within a portion of the substrate from the first primary surface to a depth of 100 nm.

52. The transparent article of any one of claims 47-49, wherein the glass-ceramic substrate further comprises a porosity of less than 10% within a portion of the substrate from the first primary surface to a depth of 100 nm.

53. The transparent article of any one of claims 47-49, wherein the article exhibits a maximum hardness over all indentation depths from 50-1000 nm of greater than 12 GPa, as measured by a Berkovich Hardness Test at the outer surface of the optical film structure.

54. The transparent article of any one of claims 47-53, wherein the physical thickness of the optical film structure is from 1250 nm to 1750 nm, the physical thickness of the scratchresistant layer is from 500 nm to 1000 nm, and optical film structure has a total of 15 to 23 layers.

55. The transparent article of any one of claims 47-54, wherein the glass-ceramic substrate comprises the following composition:55-75 mol% SiO2;0.2-10 mol% A12O3;0.2-3 mol% P2O5;0-5 mol% B2OS;15-30 mol% Li2O;0-2 mol% Na2O;0-2 mol% K2O;0-2 mol% MgO;0-2 mol% ZnO;0.1-10 mol% ZrO2;0-4 mol% TiO2;0.01-1.0 mol% SnO2; and 0-2 mol% Y2O3.

56. The transparent article of any one of claims 47-54, wherein the glass-ceramic substrate consists essentially of the following composition:68-72 mol% SiO2;3-5 mol% AI2O3;0.6- 1.2 mol% P2O5;17-25 mol% Li2O;0.01-1.7 mol% Na2O;0-5 mol% B2OS;0.01-0.5 mol% K2O;1.5-3 mol% ZrO2;0.01-0.1 mol% SnO2;0.01-0.1 mol% HfO2; and0.01-0.5 mol% Fe2C>3.

57. The transparent article of claim 56, wherein the glass-ceramic substrate further comprises the following phase assemblage:10-21 wt.% glass;40-50 wt.% lithium disilicate (Li2Si20s);35-45 wt.% petalite (LiAlSi40io); and<2 wt.% of other phases.

58. The transparent article of any one of claims 47-57, wherein the glass-ceramic substrate is a non-planar glass-ceramic substrate.

59. The transparent article of any one of claims 47-58, further comprising: a surface modifying layer, wherein the surface modifying layer is disposed on the outer surface of the optical fdm structure.

60. The transparent article of any one of claims 47-59, wherein the article exhibits a variation of less than 1% in a first-surface reflectance, as measured from 0° to 10° incidence within a range from 450 run to 700 nm, the variation defined as the difference between the maximum and minimum first-surface reflectance measured in any 100 nm increment within the range.

61. The transparent article of any one of claims 47-60, wherein the article exhibits a first- surface average photopic reflectance of less than 1%, as measured from 0° to 10° incidence, and further wherein the article exhibits a first-surface reflectance of less than 3.5%, as measured at an infrared wavelength of 940 nm from 0° to 10° incidence.

62. The transparent article of any one of claims 47-61, wherein the optical film structure further comprises an outer structure and an inner structure, the scratch-resistant layer disposed between the outer and inner structures, the inner structure disposed on the first primary surface, the outer structure comprising a plurality of alternating low and high RI layers, and the inner structure comprises a plurality of alternating high RI layers and low RI layers.

63. The transparent article of claim 62, wherein the high RI layers and the low RI layers of the plurality of alternating high and low RI layers of the inner structure are SiOxNyand SiC>2, respectively, wherein the low RI layers and high RI layers of the plurality of alternatinglow RI and high RI layers of the outer structure are SiCh and SiNx, respectively, and wherein the scratch-resistant layer is SiOxNy.

64. A transparent article, comprising: a glass-ceramic substrate comprising a first primary surface and a second primary surface, the primary surfaces opposing one another; and an optical film structure having an outer surface and a physical thickness of from about 200 nm to 5000 nm, the optical film structure disposed on the first primary surface, wherein the optical film structure comprises a scratch-resistant layer, at least one low refractive index (RI) layer, at least one medium RI layer, and at least one high RI layer, wherein the optical film structure further comprises an outer structure and an inner structure, the scratch-resistant layer disposed between the outer and inner structures, the inner structure disposed on the first primary surface, and the outer structure comprising a capping layer and a plurality of alternating high and medium RI layers, wherein each medium RI layer comprises a refractive index from 1.55 to 1.9, each of the high RI layers comprises a refractive index of greater than 1.80, and each of the low RI layers comprises a refractive index from 1.35 to 1.7, and further wherein the first primary surface of the glass-ceramic substrate comprises a surface roughness (Ra) of less than 1.5 nm.

65. The transparent article of claim 64, wherein the inner structure comprises a plurality of alternating medium RI layers and low RI layers.

66. The transparent article of claim 64 or claim 65, wherein the glass-ceramic substrate comprises an elastic modulus of greater than 85 GPa and a fracture toughness of greater than 0.8 MPa-^ / m, wherein the optical film structure exhibits a residual compressive stress of greater than or equal to 700 MPa and an elastic modulus of greater than or equal to 140 GPa.

67. The transparent article of any one of claims 64-66, wherein the article exhibits an average failure stress of 700 MPa or greater in a ring-on-ring (ROR) test with the outer surface of the optical film structure placed in tension.

68. The transparent article of any one of claims 64-67, wherein the transparent article further comprises a top coating, the top coating is disposed on the capping layer, and further wherein the top coating comprises a surface -modifying layer and a planarization layer, the planarization layer disposed on the capping layer.

69. The transparent article of claim 68, wherein the planarization layer has a physical thickness of from 10 nm to 60 nm, comprises a silica or a silica-like network comprising Si- O-Si-O bonds, and comprises a molar ratio of hydrogen to silica of about 0.2 or more.

70. The transparent article of claim 69, wherein the molar ratio of hydrogen to silica is from about 0.2 to 0.4.

71. The transparent article of any one of claims 68-70, wherein the planarization layer comprises a surface roughness (Ra) of from 0. 1 nm to 3 nm.

72. The transparent article of any one of claims 68-70, wherein a ratio of a surface roughness (Ra) of the planarization layer to the surface roughness (Ra) of the capping layer disposed beneath it is 0.9 or less.

73. The transparent article of any one of claims 68-72, wherein the surface -modifying layer comprises octadecyl trimethoxysilane (OTS) and the planarization layer comprises a silica-like structure derived from an octa-isobutyl polyhedral oligomeric silsesquioxane (OB- PSS).

74. The transparent article of any one of claims 64-73, wherein the high and medium RI layers of the outer structure are SiNxand SiOxNy, respectively, and the medium RI layers and low RI layers of the inner structure are SiOxNyand SiCh. respectively, wherein the capping layer comprises SiCh. and further wherein the scratch-resistant layer comprises SiOxNy.

75. The transparent article of any one of claims 64-74, wherein the glass-ceramic substrate comprises the following composition:55-75 mol% SiO2;0.2-10 mol% Al2O3;0.2-3 mol% P2O5;0-5 mol% B2O3;15-30 mol% Li2O;0-2 mol%Na2O;0-2 mol% K2O;0-2 mol% MgO;0-2 mol% ZnO;0.1-10 mol% ZrO2;0-4 mol% TiO2;0.01-1.0 mol% SnO2; and0-2 mol%Y2O3.

76. The transparent article of any one of claims 64-74, wherein the glass-ceramic substrate consists essentially of the following composition:68-72 mol% SiO2;3-5 mol% Al2O3;0.6- 1.2 mol% P2O5;17-25 mol% Li2O;0.01-1.7 mol% Na2O;0-5 mol% B2O3;0.01-0.5 mol% K2O;1.5-3 mol% ZrO2;0.01-0.1 mol% SnO2;0.01-0.1 mol% HfO2; and0.01-0.5 mol% Fe2O3.

77. The transparent article of claim 76, wherein the glass-ceramic substrate further comprises the following phase assemblage:10-21 wt.% glass;40-50 wt.% lithium disilicate (Li2Si20s);35-45 wt.% petalite (LiAlSi40io); and<2 wt.% of other phases.

Images