Patent Application
20240329281
The disclosure relates to durable and scratch resistant optical film structures and cover articles, and more particularly to optical film structures and cover articles exhibiting high hardness, particular colors or hues, high color saturation and low variation in color or hue over various viewing angles.
Cover articles are often used to protect critical devices within electronic products, to provide a user interface for input and/or display, and/or for many other functions. Such products include mobile devices, such as smart phones, mp3 players, smart watches, and computer tablets. Cover articles also include 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. These applications often demand scratch-resistance (e.g., as manifested by high hardness) and strong optical performance characteristics, e.g., in terms of maximum light transmittance and minimum reflectance.
These cover articles, for example, can be used as protective covers for display devices (e.g., smart phone faces) and/or cover substrates for housings (e.g., a back cover of a smart phone face). In addition, some applications for these cover articles benefit from or otherwise require the appearance of color in reflectance and/or limited color in transmittance (e.g., a smart phone face with a red hue in reflectance). The need for these cover articles to exhibit certain colors or hues may be for function (e.g., to enhance digital display characters) and/or customer-desired aesthetics (e.g., a smart phone with a blue color as a fashion accent). There is also a need for such cover articles to exhibit a desired color or hue with high saturation and limited variability in color across various viewing angles.
Generally, the disclosure is directed to optical film structures and cover articles that address the aforementioned needs and other needs in the prior art. The disclosed cover articles employ an optical film structure disposed on a substrate (e.g., a glass substrate, Corning® Gorilla Glass® products, a glass-ceramic substrate, etc.). These optical film structures and cover articles have high hardness and advantageous optical properties suitable for various applications, including smart phone and mobile phone displays and covers. The optical film structure of the cover article is a designed, multilayer film structure, and the cover articles of the disclosure reflect new system-level designs configured to exhibit particular colors or hues, with high saturation and limited color variability over a wide viewing angle range.
According to an aspect of the disclosure, a cover article is provided that includes: a substrate comprising an outer primary surface and an inner primary surface, the outer and inner primary surfaces are opposite of one another; and an optical film structure comprising an outermost surface disposed on the outer or inner primary surface of the substrate. The optical film structure comprises a plurality of alternating high refractive index and low refractive index layers. Each of the high refractive index layers has a refractive index greater than a refractive index of each of the low refractive index layers. Further, the cover article exhibits a substantially constant hue in reflectance with a D65 illuminant, as given by an exhibited color with a variation in Hue Angle (h*) of less than 50 degrees over a viewing angle range from 0 to 60 degrees. This aspect can serve as a durable and/or scratch resistant cover article for electronic devices and, more particularly, a cover article exhibiting hardness, a particular color or hue, a high color saturation and a low variation in color or hue over various viewing angles.
According to an aspect of the disclosure, a cover article is provided that includes: a substrate comprising an outer primary surface and an inner primary surface, the outer and inner primary surfaces are opposite of one another; and an optical film structure comprising an outermost surface disposed on the outer or inner primary surface of the substrate. The optical film structure comprises a plurality of alternating high refractive index and low refractive index layers. Each of the high refractive index layers has a refractive index greater than a refractive index of each of the low refractive index layers. Further, the cover article exhibits a substantially neutral color in reflectance with a D65 illuminant, as given by an exhibited grey hue or silver hue, each with a Chroma (c*) of less than 10. This aspect can serve as a durable and/or scratch resistant cover article for electronic devices and, more particularly, a cover article exhibiting hardness, a neutral color, a high neutral color saturation and a low variation in neutral color over various viewing angles.
According to another aspect of the disclosure, a cover article is provided that includes: a substrate comprising an outer primary surface and an inner primary surface, the outer and inner primary surfaces are opposite of one another; and an optical film structure comprising an outermost surface disposed on the outer or inner primary surface of the substrate. The optical film structure comprises a plurality of alternating high refractive index and low refractive index layers. Each of the high refractive index layers has a refractive index greater than a refractive index of each of the low refractive index layers. In addition, the optical film structure has a physical thickness that ranges from 1000 nm to 4000 nm. One of the high refractive index layers is a scratch resistant layer having a physical thickness from 500 nm to 3000 nm. One of the low refractive index layers is a capping layer disposed over the scratch resistant layer. A portion of the plurality of the plurality of alternating high refractive index and low refractive index layers is between the scratch resistant layer and the substrate. Further, the optical film structure exhibits a hardness of at least 12 GPa, as measured with a Berkovich Indenter Hardness Test from the outermost surface of the optical film structure to a depth from about 100 nm to about 300 nm. In addition, the cover article exhibits a substantially constant hue in reflectance with a D65 illuminant, as given by an exhibited color with a variation in Hue Angle (h*) of less than 50 degrees over a viewing angle range from 0 to 60 degrees. This aspect can serve as a durable and/or scratch resistant cover article for electronic devices and, more particularly, a cover article exhibiting high hardness, a particular color or hue, a high color saturation and a low variation in color or huc over various viewing angles.
According to another aspect of the disclosure, a cover article is provided that includes: a substrate comprising an outer primary surface and an inner primary surface, the outer and inner primary surfaces are opposite of one another; and an optical film structure comprising an outermost surface disposed on the outer or inner primary surface of the substrate. The optical film structure comprises a plurality of alternating high refractive index and low refractive index layers. Each of the high refractive index layers has a refractive index greater than a refractive index of each of the low refractive index layers. In addition, the optical film structure has a physical thickness that ranges from 1000 nm to 4000 nm. One of the high refractive index layers is a scratch resistant layer having a physical thickness from 500 nm to 3000 nm. One of the low refractive index layers is a capping layer disposed over the scratch resistant layer. A portion of the plurality of alternating high refractive index and low refractive index layers is between the scratch resistant layer and the substrate. Further, the optical film structure exhibits a hardness of at least 12 GPa, as measured with a Berkovich Indenter Hardness Test from the outermost surface of the optical film structure to a depth from about 100 nm to about 300 nm. In addition, the cover article exhibits a substantially neutral color in reflectance with a D65 illuminant, as given by an exhibited grey hue or silver hue, each with a Chroma (c*) of less than 10. This aspect can serve as a durable and/or scratch resistant cover article for electronic devices and, more particularly, a cover article exhibiting high hardness, a neutral color, a high neutral color saturation and a low variation in neutral color over various viewing angles.
According to a further aspect of the disclosure, a cover article is provided that includes: a substrate comprising an outer primary surface and an inner primary surface, the outer and inner primary surfaces are opposite of one another; and an optical film structure comprising an outermost surface disposed on the outer or inner primary surface of the substrate. The optical film structure comprises a plurality of alternating high refractive index and low refractive index layers. Each of the high refractive index layers has a refractive index greater than a refractive index of each of the low refractive index layers. In addition, the optical film structure has a physical thickness that ranges from 250 nm to 1000 nm. Further, the optical film structure exhibits a hardness of at least 8 GPa, as measured with a Berkovich Indenter Hardness Test from the outermost surface of the optical film structure to a depth from about 100 nm to about 300 nm. In addition, the cover article exhibits a substantially constant hue in reflectance with a D65 illuminant, as given by an exhibited color with a variation in Huc Angle (h*) of less than 50 degrees over a viewing angle range from 0 to 60 degrees. This aspect can serve as a durable and/or scratch resistant cover article for electronic devices and, more particularly, a cover article exhibiting hardness, a particular color or hue, a high color saturation and a low variation in color or hue over various viewing angles.
According to a further aspect of the disclosure, a cover article is provided that includes: a substrate comprising an outer primary surface and an inner primary surface, the outer and inner primary surfaces are opposite of one another; and an optical film structure comprising an outermost surface disposed on the outer or inner primary surface of the substrate. The optical film structure comprises a plurality of alternating high refractive index and low refractive index layers. Each of the high refractive index layers has a refractive index greater than a refractive index of each of the low refractive index layers. In addition, the optical film structure has a physical thickness that ranges from 250 nm to 1000 nm. Further, the optical film structure exhibits a hardness of at least 8 GPa, as measured with a Berkovich Indenter Hardness Test from the outermost surface of the optical film structure to a depth from about 100 nm to about 300 nm. In addition, the cover article exhibits a substantially neutral color in reflectance with a D65 illuminant, as given by an exhibited grey hue or silver hue, each with a Chroma (c*) of less than 10. This aspect can serve as a durable and/or scratch resistant cover article for electronic devices and, more particularly, a cover article exhibiting hardness, a neutral color, a high neutral color saturation and a low variation in neutral color over various viewing angles.
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.
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 embodiment(s), and together with the description serve to explain principles and operation of the various embodiments.
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.
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.
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.
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; the number or type of embodiments described in the specification.
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.
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 the material and the surface. The intervening material(s) may constitute a layer, as defined herein.
As used herein, the terms “low 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 cover article according to the disclosure (i.e., low RI layer<high RI layer). Hence, low RI layers have refractive index values that are less than the refractive index values of high RI layers. Further, as used herein, “low RI layer” and “low index layer” are interchangeable with the same meaning. Likewise, “high RI layer” and “high index layer” are interchangeable with the same meaning.
As used herein, the term “strengthened substrate” refers to a substrate employed in a cover 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.
As used herein, the “Berkovich Indenter Hardness Test” and “Berkovich Hardness Test” are used interchangeably to refer to a test for measuring the hardness of a material on a surface 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 an outer layered film of a cover article of the disclosure (e.g., the optical film structure 120 shown in
Typically, in nanoindentation measurement methods (such as the Berkovich Indenter Hardness Test) of a coating or film that 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 and then increases and reaches a maximum value or plateau at deeper indentation depths. Thereafter, hardness begins to decrease at even deeper indentation depths due to the effect of the underlying substrate. Where a substrate having an increased hardness compared to the coating is utilized, the same effect can be seen; however, the hardness increases at deeper indentation depths due to the effect of the underlying substrate. The indentation depth range and the hardness values at certain indentation depth range(s) can be selected to identify a particular hardness response of the optical film structures and layers thereof, described herein, without the effect of the underlying substrate.
When measuring hardness of the outer layered film of the cover articles of the disclosure according to the Berkovich Indenter Hardness Test, 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. The substrate influence on hardness occurs at deeper indentation depths (i.e., typically at depths greater than about 10% of the optical film structure or layer thickness). 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.
At shallow indentation depths (which also may be characterized as small loads) (e.g., up to about 50 nm), the apparent hardness of a material appears to increase dramatically versus indentation depth. This shallow 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 substrate becomes more pronounced as the indentation depths increase. Hardness may begin to drop dramatically once the indentation depth exceeds about 30% of the outer layered film of the cover articles of the disclosure (e.g., the optical film structure 120 shown in
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 cover article, the substrate, the outer layered 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 cover article, the substrate, or the outer layered 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.
In addition, “average reflectance” can be determined over the visible spectrum, infrared spectrum, or over other wavelength ranges, according to measurement principles understood by those skilled in the field of the disclosure. Unless otherwise noted, all reflectance values reported or otherwise referenced in this disclosure are associated with testing through the outer layered film of the cover articles and off of the primary surface of the substrate on which the outer layered film is disposed, e.g., a “first-surface” average reflectance over a specified range of wavelengths, a “first-surface” reflectance at a particular wavelength, etc.
In addition, “average transmittance” can be determined over the visible spectrum, infrared spectrum or other wavelength ranges, according to measurement principles understood by those skilled in the field of the disclosure. Unless otherwise noted, all transmittance values reported or otherwise referenced in this disclosure are associated with testing through both primary surfaces of the substrate and the outer layered film of the cover articles, e.g., a “two-surface” average transmittance over a specified range of wavelengths, a “two-surface” transmittance at a particular wavelength, etc.
As used herein, “reflected color” and “transmitted color” refers to the color reflected or transmitted through the cover articles of the disclosure with regard to color in the CIE L*,a*,b* colorimetry system under a D65 illuminant. More specifically, the “reflected color” or “transmitted color” can be given by V (a*2+b*2) or as a*, b* coordinates, as these color coordinates are measured through reflectance or transmittance of a D65 illuminant through the primary surfaces of the substrate of the cover article over an incident angle range, e.g., from 0 degrees to 10 degrees, from 0 degrees to 45 degrees, from 0 degrees to 90 degrees, etc.
As used herein, in a cylindrical 1964 CIE (L*, C*, h*) color space, “Chroma (c*)” is the magnitude of the distance from the origin (c*(ab)); “Hue Angle (h*)” is the angle from 0° to 360° (h*(ab)); and color saturation is defined as s*((ab)=(c*((ab))/L* (scc
Aspects of the disclosure are directed to cover articles that employ an optical film structure disposed on a substrate (e.g., a glass substrate, Corning® Gorilla Glass® products, a glass-ceramic substrate, etc.). These cover articles, and their optical film structures, have high hardness and advantageous optical properties suitable for various applications, including smart phone and mobile phone displays and covers. The optical film structures of the cover articles are indicative of a designed, multilayer film structure, and the cover articles of the disclosure reflect new system-level designs configured to exhibit particular colors or hues, with high saturation and low color variability over a wide viewing angle range.
The cover articles and optical film structures of the disclosure can be employed in a variety of applications, including as protective covers for display devices (e.g., smart phone faces) and/or cover substrates for housings (e.g., a back cover of a smart phone face). In addition, some applications for these cover articles benefit from or otherwise require the appearance of color in reflectance and/or no to limited color in transmittance (e.g., a smart phone face with a red hue in reflectance). The need for these cover articles to exhibit certain colors or hues may be for function (e.g., to enhance digital display characters) and/or customer-desired aesthetics (e.g., a smart phone with a blue color as a fashion accent). It is also desirable for such cover articles to exhibit a desired color or hue with high saturation and limited variability in color across various viewing angles. In some configurations, ink can be applied to the backside of these cover articles to provide enhanced color reflectance or even a gradient of ink color for different decorative color reflection effects. Conversely, for certain applications with no ink where transmission is desired, the cover articles of the disclosure can exhibit little to no color which can be attractive for dead front applications (e.g., as a cover article for a smart phone display; see also the exemplary electronic device of
In some implementations, cover articles of the disclosure employ optical film structures having a physical thickness from 1000 to 4000 nm (or 2500 to 4000 nm) can be classified according to five categories in the 1964 CIE (L*, c*, and h*) color space: A) pink or red with a Hue Angle (h*) of 320° to 40°; B) yellow with a Hue Angle (h*) of 40° to 135°; C) green with a Hue Angle (h*) of 135° to 200°; D) blue or purple with a Hue Angle (h*) of 200° to 320°; and E) silver or grey with a Hue Angle (h*) of any angle and a Chroma (c*)<10. According to other implementations, cover articles of the disclosure employ optical film structures having a physical thickness from 250 to 1000 nm (or 400 to 700 nm) and exhibit colors and hues according to the foregoing Categories A)-E).
Reference will now be made in detail to various embodiments of cover articles, examples of which are illustrated in the accompanying drawings. Referring to
The optical film structure 120 includes at least one layer of at least one material. 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-layers 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.
The physical thickness of the optical film structure 120, as depicted in
As also shown in
As shown in
In some embodiments, the optical film structure 120 may include up to twenty-five (25) periods. For example, the optical film structure 120, as depicted in
In the embodiments shown in
As used herein, the terms “low RI” and “high RI” refer to the relative values for the refractive index of the layers 130A and 130B relative to one another (e.g., low RI<high RI). In one or more embodiments, the term “low RI” when used with the low RI layers 130A, includes a range from about 1.3 to about 1.7 or 1.75. In one or more embodiments, the term “high RI” when used with the high RI layers 130B, includes a range from about 1.7 to about 2.6 (e.g., about 1.85 or greater).
Materials suitable for use in the optical film structure 120 include: SiO2, Al2O3, GeO2, SiO, AlOxNy, AlN, SiNx, SiOxNy, SiuAlvOxNy, Ta2O5, Nb2O5, TiO2, ZrO2, TiN, MgO, MgF2, BaF2, CaF2, SnO2, HfO2, Y2O3, MoO3, DyF3, YbF3, YF3, CeF3, polymers, fluoropolymers, plasma-polymerized polymers, siloxane polymers, silsesquioxanes, polyimides, fluorinated polyimides, polyetherimide, polyethersulfone, polyphenylsulfone, polycarbonate, polyethylene terephthalate, polyethylene naphthalate, acrylic polymers, urethane polymers, polymethylmethacrylate, other materials cited below as suitable for use in a scratch resistant layer, and other materials known in the art. Some examples of suitable materials for use in the low RI layers 130A include SiO2, Al2O3, GeO2, SiO, AlOxNy, SiOxNy, SiuAlvOxNy, MgO, MgAl2O4, MgF2, BaF2, CaF2, DyF3, YbF3, YF3, and CeF3. The nitrogen content of the materials for use in the first low RI layer may be minimized (e.g., in materials such as Al2O3 and MgAl2O4). Some examples of suitable materials for use in the high RI layers 130B include SiuAlvOxNy, Ta2O5, Nb2O5, AlN, Si3N4, AlOxNy, SiOxNy, SiNx, SiNx: Hy, HfO2, TiO2, ZrO2, Y2O3, Al2O3, MoO3 and diamond-like carbon.
In examples, the high RI layer 130B may also be a high hardness layer or a scratch resistant layer (e.g., scratch resistant layer 150 as shown in
The hardness of the high RI layers 130B and/or the scratch resistant layer 150 may be characterized specifically. In some embodiments, the maximum hardness of the high RI layers 130B and/or a scratch resistant layer 150, as measured by the Berkovich Indenter Hardness Test at an indentation depth of about 100 nm or greater, may be about 8 GPa or greater, about 10 GPa or greater, about 12 GPa or greater, about 15 GPa or greater, about 18 GPa or greater, or about 20 GPa or greater. In some cases, the high RI layer 130B material may be deposited as a single layer and may be characterized as a scratch resistant layer (e.g., scratch resistant layer 150), and this single layer may have a thickness between about 200 nm and 10000 nm for repeatable hardness determination. In other embodiments in which the high RI layer 130B is deposited as a single layer (e.g., as a scratch-resistant layer 150, as depicted in
In one or more embodiments, one or more of the low RI layers 130A and high RI layers 130B of the optical film structure 120 may include a specific physical thickness range. These layer(s) 130A and/or 130B of the optical film structure 120 may include a physical thickness in the range from about 1 nm to about 400 nm, from about 5 nm to about 300 nm, from about 5 nm to about 200 nm, from about 10 nm to about 200 nm, or from about 10 nm to about 250 nm. In some embodiments, all or a majority of the layers in the optical film structure 120 may each have a physical thickness in the range from about 1 nm to about 400 nm, from about 5 nm to about 300 nm, from about 5 nm to about 200 nm, from about 10 nm to about 200 nm, or from about 10 nm to about 250 nm. In some embodiments, the outermost high refractive index layer 130B of the cover article 100 has a physical thickness of greater than 150 nm, greater than 200 nm or even greater than 225 nm. In other implementations of the cover article 100, greater than 50%, greater than 55% or even greater than 60%, of the outermost physical thickness of the optical film structure 120 comprises high refractive index material, i.e., the material of high RI layers 130B. In further implementations, the outermost high RI layer 130B has a physical thickness that exceeds the physical thickness of the outermost low RI layer 130A or capping layer 131, which can enhance hardness values of the optical film structure 120 and its cover article 100.
In some embodiments, as shown in exemplary form in
In one or more embodiments, the combined physical thickness of the high RI layer(s) 130B may be characterized. The combined thickness is the calculated combination of the thicknesses of the individual high RI layer(s) 130B in the optical film structure 120, even when there are intervening low RI layer(s) 130A or other layer(s). In some embodiments, the combined physical thickness of the high RI layer(s) 130B, which may also comprise a high-hardness material (e.g., a nitride or an oxynitride material), may be greater than 30% of the total physical thickness of the optical film structure 120. For example, the combined physical thickness of the high RI layer(s) 130B may be about 25% or greater, 30% or greater, 35% or greater, 40% or greater, about 50% or greater, or even about 60% or greater, of the total physical thickness of the optical film structure 120.
As noted earlier, the cover article 100 may include one or more additional coatings 140 disposed on the optical film structure 120, as shown in exemplary form in
In other embodiments, the additional coating 140 can include a scratch resistant layer or layers (e.g., with a composition similar to scratch resistant layer 150). In some embodiments, the additional coating 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 additional coatings may have a thickness in the range from about 5 nm to about 20 nm. The constituents of the additional coating 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.
As mentioned herein, the optical film structure 120 of the cover article 100 depicted in
Exemplary materials used in the scratch resistant layer 150 (or the scratch resistant layer used as an additional coating, as noted earlier) may include an inorganic carbide, nitride, oxide, diamond-like material, or combination of these. 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 or coating may include Al2O3, AlN, AlOxNy, Si3N4, SiNx, SiOxNy, SiuAlvOxNy, diamond, diamond-like carbon, SixCy, SixOyCz, ZrO2, TiOxNy and combinations thereof. The scratch resistant layer 150 may also comprise nanocomposite materials, or materials with a controlled microstructure to improve hardness, toughness, or abrasion/wear resistance. For example, the scratch resistant layer 150 may comprise nanocrystallites in the size range from about 5 nm to about 30 nm. In embodiments, the scratch resistant layer 150 may comprise transformation-toughened zirconia, partially stabilized zirconia, or zirconia-toughened alumina. In embodiments, the scratch resistant layer 150 exhibits a fracture toughness value greater than about 1 MPavm and simultaneously exhibits a hardness value greater than about 8 GPa.
The scratch resistant layer 150 may include a single layer (as shown in
The scratch resistant layer 150 (e.g., as shown in
In one exemplary embodiment of the cover article 100 of the disclosure, as depicted in exemplary form in
In another exemplary embodiment of the cover article 100 of the disclosure, as depicted in exemplary form in
In certain implementations of the cover article 100 depicted in
In an additional exemplary embodiment of the cover article 100 of the disclosure, as depicted in exemplary form in
In certain implementations of the cover article 100 depicted in
The optical film structure 120 and/or the cover article 100 may be described in terms of a hardness measured by the Berkovich Indenter Hardness Test. As noted earlier, the Berkovich Indenter Hardness Test includes indenting the outermost surface 122 of the cover article 100 (see
In some embodiments, the cover article 100 (e.g., as depicted in
According to some implementations of the cover articles 100 of the disclosure, as depicted in exemplary form in
Cover articles 100 of the disclosure, as depicted in exemplary form in
In some implementations of the cover articles 100 of the disclosure, as depicted in exemplary form in
In some implementations of the cover articles 100 of the disclosure, as depicted in exemplary form in
In some implementations of the cover articles 100 of the disclosure, as depicted in exemplary form in
In some implementations of the cover articles 100 of the disclosure, as depicted in exemplary form in
In some implementations of the cover articles 100 of the disclosure, as depicted in exemplary form in
The substrate 110 may include an inorganic material and may include an amorphous substrate, a crystalline substrate, or a combination thereof. The substrate 110 may be formed from man-made materials and/or naturally occurring materials (e.g., quartz and polymers). For example, in some instances, the substrate 110 may be characterized as organic and may specifically be polymeric. Examples of suitable polymers include, without limitation: thermoplastics including polystyrene (PS) (including styrene copolymers and blends), polycarbonate (PC) (including copolymers and blends), polyesters (including copolymers and blends, including polyethyleneterephthalate and polyethyleneterephthalate copolymers), polyolefins (PO) and cyclicpolyolefins (cyclic-PO), polyvinylchloride (PVC), acrylic polymers including polymethyl methacrylate (PMMA) (including copolymers and blends), thermoplastic urethanes (TPU), polyetherimide (PEI) and blends of these polymers with each other. Other exemplary polymers include epoxy, styrenic, phenolic, melamine, and silicone resins.
In some specific embodiments, the substrate 110 may specifically exclude polymeric, plastic and/or metal materials. The substrate 110 may be characterized as alkali-including substrates (i.e., the substrate 110 includes one or more alkalis). In one or more embodiments, the substrate 110 exhibits a refractive index in the range from about 1.45 to about 1.55. In specific embodiments, the substrate 110 may exhibit an average strain-to-failure at a surface on one or more opposing primary surfaces that is 0.5% or greater, 0.6% or greater, 0.7% or greater, 0.8% or greater, 0.9% or greater, 1% 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 ball-on-ring testing using at least 5, at least 10, at least 15, or at least 20 samples, as understood by those skilled in the field of this disclosure. In specific embodiments, the substrate 110 may exhibit an average strain-to-failure at its surface on one or more opposing primary surfaces 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.
Suitable substrates 110 may exhibit an elastic modulus (or Young's modulus) in the range from about 30 GPa to about 120 GPa. In some instances, the elastic modulus of the substrate may be in the range from about 30 GPa to about 110 GPa, from about 30 GPa to about 100 GPa, from about 30 GPa to about 90 GPa, from about 30 GPa to about 80 GPa, from about 30 GPa to about 70 GPa, from about 40 GPa to about 120 GPa, from about 50 GPa to about 120 GPa, from about 60 GPa to about 120 GPa, from about 70 GPa to about 120 GPa, and all ranges and sub-ranges therebetween.
In one or more embodiments, the amorphous substrate may include glass, which may be strengthened or non-strengthened. Examples of suitable glass include soda lime glass, alkali aluminosilicate glass, alkali containing borosilicate glass and alkali aluminoborosilicate glass. In some variants, the glass may be free of lithia. In one or more alternative embodiments, the substrate 110 may include crystalline substrates such as glass ceramic substrates (which may be strengthened or non-strengthened) or may include a single crystal structure, such as sapphire. In one or more specific embodiments, the substrate 110 includes an amorphous base (e.g., glass) and a crystalline cladding (e.g., a sapphire layer, a polycrystalline alumina layer and/or or a spinel (MgAl2O4) layer).
The substrate 110 of one or more embodiments may have a hardness that is less than the hardness of the overall cover article 100 (as measured by the Berkovich Indenter Hardness Test described herein). Unless otherwise noted, the hardness of the substrate 110 is measured using the Berkovich Indenter Hardness Test.
The substrate 110 may be substantially optically clear, transparent and free from light scattering elements. In such embodiments, the substrate 110 may exhibit an average light transmittance over the optical wavelength regime of 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, or about 92% 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 outermost surface 122 of the optical film structure 120 only, without taking into account the opposite surface). 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 substrate primary surface 112 (however, such measurements may be provided at incident illumination angles of 45 degrees or 60 degrees). The substrate 110 may optionally exhibit a color, such as white, black, red, blue, green, yellow, orange, etc.
Additionally or alternatively, the physical thickness of the 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. The length, width and physical thickness dimensions of the substrate 110 may also vary according to the application or use of the cover article 100.
The substrate 110 may be provided using a variety of different processes. For instance, where the substrate 110 includes an amorphous substrate such as glass, various forming methods can include float glass processes and down-draw processes such as fusion draw and slot draw.
Once formed, a substrate 110 may be strengthened to form a strengthened substrate. As used herein, the term “strengthened substrate” may refer to a substrate 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.
Where the substrate 110 is chemically strengthened by an ion exchange process, the ions in the surface layer of the substrate 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 in a salt bath (or baths), use of multiple salt baths, additional steps such as annealing, washing, and the like, are generally determined by the composition of the substrate and the desired compressive stress (CS), depth of compressive stress layer (or depth of layer DOL, or depth of compression DOC) of the substrate that result from the strengthening operation. By way of example, ion exchange of alkali metal-containing glass 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 450° 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 addition, non-limiting examples of ion exchange processes in which glass substrates are immersed in multiple ion exchange baths, with washing and/or annealing steps between immersions, are described in U.S. patent application Ser. No. 12/500,650, filed Jul. 10, 2009, by Douglas C. Allan et al., entitled “Glass with Compressive Surface for Consumer Applications” and claiming priority from U.S. Provisional Patent Application No. 61/079,995, filed Jul. 11, 2008, in which glass substrates are strengthened by immersion in multiple, successive, ion exchange treatments in salt baths of different concentrations; and U.S. Pat. No. 8,312,739, by Christopher M. Lee et al., issued on Nov. 20, 2012, and entitled “Dual Stage Ion Exchange for Chemical Strengthening of Glass,” and claiming priority from U.S. Provisional Patent Application No. 61/084,398, filed Jul. 29, 2008, in which glass substrates are strengthened by ion exchange in a first bath diluted with an effluent ion, followed by immersion in a second bath having a smaller concentration of the effluent ion than the first bath. The contents of U.S. patent application Ser. No. 12/500,650 and U.S. Pat. No. 8,312,739 are incorporated herein by reference in their entirety.
The degree of chemical strengthening achieved by ion exchange may be quantified based on the parameters of central tension (CT), surface CS, and depth of compression (DOC). Compressive stress (including surface CS) is measured by 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. 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. Maximum CT values are measured using a scattered light polariscope (SCALP) technique known in the art. As used herein, DOC means the depth at which the stress in the chemically strengthened alkali aluminosilicate glass article described herein changes from compressive to tensile. DOC may be measured by FSM or SCALP depending on the ion exchange treatment. Where the stress in the glass article is generated by exchanging potassium ions into the glass article, FSM is used to measure DOC. Where the stress is generated by exchanging sodium ions into the glass article, SCALP is used to measure DOC. Where the stress in the glass article is generated by exchanging both potassium and sodium ions into the glass, the DOC is measured by SCALP, since it is believed the exchange depth of sodium indicates the DOC and the exchange depth of potassium ions indicates a change in the magnitude of the compressive stress (but not the change in stress from compressive to tensile); the exchange depth of potassium ions in such glass articles is measured by FSM.
In one embodiment, a substrate 110 can have a surface CS of 200 MPa or greater, 250 MPa or greater, 300 MPa or greater, e.g., 400 MPa or greater, 450 MPa or greater, 500 MPa or greater, 550 MPa or greater, 600 MPa or greater, 650 MPa or greater, 700 MPa or greater, 750 MPa or greater or 800 MPa or greater. The strengthened substrate may have a DOC (formerly DOL) of 10 μm or greater, 15 μm or greater, 20 μm or greater (e.g., 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm or greater) and/or a CT of 10 MPa or greater, 20 MPa or greater, 30 MPa or greater, 40 MPa or greater (e.g., 42 MPa, 45 MPa, or 50 MPa or greater) but less than 100 MPa (e.g., 95, 90, 85, 80, 75, 70, 65, 60, 55 MPa or less). In one or more specific embodiments, the strengthened substrate has one or more of the following: a surface CS greater than 500 MPa, a DOC (formerly DOL) greater than 15 μm, and a CT greater than 18 MPa.
Example glasses that may be used in the substrate 110 may include alkali aluminosilicate glass compositions or alkali aluminoborosilicate glass compositions, though other glass compositions are contemplated. Such glass compositions are capable of being chemically strengthened by an ion exchange process. One example glass composition comprises SiO2, B2O3 and Na2O, where (SiO2+B2O3)≥66 mol. %, and Na2O≥9 mol. %. In an embodiment, the glass composition includes at least 6 wt. % aluminum oxide. In a further embodiment, the substrate includes a glass composition with one or more alkaline earth oxides, such that a content of alkaline earth oxides is at least 5 wt. %. Suitable glass compositions, in some embodiments, further comprise at least one of K2O, MgO, and CaO. In a particular embodiment, the glass compositions used in the substrate can comprise 61-75 mol. % SiO2; 7-15 mol. % Al2O3; 0-12 mol. % B2O3; 9-21 mol. % Na2O; 0-4 mol. % K2O; 0-7 mol. % MgO; and 0-3 mol. % CaO.
A further example glass composition suitable for the substrate 110 comprises: 60-70 mol. % SiO2; 6-14 mol. % Al2O3; 0-15 mol. % B2O3; 0-15 mol. % Li2O; 0-20 mol. % Na2O; 0-10 mol. % K2O; 0-8 mol. % MgO; 0-10 mol. % CaO; 0-5 mol. % ZrO2; 0-1 mol. % SnO2; 0-1 mol. % CeO2; less than 50 ppm As2O3; and less than 50 ppm Sb2O3; where 12 mol. %≤(Li2O+Na2O+K2O)≤20 mol. % and 0 mol. %≤(MgO+CaO)≤10 mol. %.
A still further example glass composition suitable for the substrate 110 comprises: 63.5-66.5 mol. % SiO2; 8-12 mol. % Al2O3; 0-3 mol. % B2O3; 0-5 mol. % Li2O; 8-18 mol. % Na2O; 0-5 mol. % K2O; 1-7 mol. % MgO; 0-2.5 mol. % CaO; 0-3 mol. % ZrO2; 0.05-0.25 mol. % SnO2; 0.05-0.5 mol. % CeO2; less than 50 ppm As2O3; and less than 50 ppm Sb2O3; where 14 mol. %≤(Li2O+Na2O+K2O)≤18 mol. % and 2 mol. %≤(MgO+CaO)≤7 mol. %.
In a particular embodiment, an alkali aluminosilicate glass composition suitable for the substrate 110 comprises alumina, at least one alkali metal and, in some embodiments, greater than 50 mol. % SiO2, in other embodiments at least 58 mol. % SiO2, and in still other embodiments at least 60 mol. % SiO2, wherein the ratio (Al2O3+B2O3)/Emodifiers (i.e., sum of modifiers) is greater than 1, where in the ratio the components are expressed in mol. % and the modifiers are alkali metal oxides. This glass composition, in particular embodiments, comprises: 58-72 mol. % SiO2; 9-17 mol. % Al2O3; 2-12 mol. % B2O3; 8-16 mol. % Na2O; and 0-4 mol. % K2O, wherein the ratio (Al2O3+B2O3)/Emodifiers (i.e., sum of modifiers) is greater than 1.
In still another embodiment, the substrate 110 may include an alkali aluminosilicate glass composition comprising: 64-68 mol. % SiO2; 12-16 mol. % Na2O; 8-12 mol. % Al2O3; 0-3 mol. % B2O3; 2-5 mol. % K2O; 4-6 mol. % MgO; and 0-5 mol. % CaO, wherein: 66 mol. %≤ SiO2+B2O3+CaO≤69 mol. %; Na2O+K2O+B2O3+MgO+CaO+SrO>10 mol. %; 5 mol. %≤MgO+CaO+SrO≤8 mol. %; (Na2O+B2O3)—Al2O3≤2 mol. %; 2 mol. %≤Na2O Al2O3≤6 mol. %; and 4 mol. %≤(Na2O+K2O)—Al2O3≤10 mol. %.
In an alternative embodiment, the substrate 110 may comprise an alkali aluminosilicate glass composition comprising: 2 mol. % or more of Al2O3 and/or ZrO2, or 4 mol. % or more of Al2O3 and/or ZrO2.
Where the substrate 110 includes a crystalline substrate, the substrate may include a single crystal, which may include Al2O3. Such single crystal substrates are referred to as sapphire. Other suitable materials for a crystalline substrate include polycrystalline alumina layer and/or spinel (MgAl2O4).
Optionally, the substrate 110 may be crystalline and include a glass ceramic substrate, which may be strengthened or non-strengthened. Examples of suitable glass ceramics may include Li2O—Al2O3—SiO2 system (i.e., LAS-System) glass ceramics, MgO—Al2O3—SiO2 system (i.e., MAS-System) glass ceramics, and/or glass ceramics that include a predominant crystal phase including β-quartz solid solution, β-spodumene ss, cordierite, and lithium disilicate. The glass ceramic substrates may be strengthened using the chemical strengthening processes disclosed herein. In one or more embodiments, MAS-System glass ceramic substrates may be strengthened in Li2SO4 molten salt, whereby an exchange of 2Li+ for Mg2+ can occur.
The substrate 110 according to one or more embodiments can have a physical thickness ranging from about 50 μm to about 5 mm in various portions of the substrate 110. Example substrate 110 physical thicknesses range from about 50 μm to about 500 μm (e.g., 50, 75, 100, 200, 300, 400 or 500 μm). Further example substrate 110 physical thicknesses can range from about 50 μm to about 5000 μm (e.g., 50, 75, 100, 250, 500, 600, 700, 800, 900, 1000, 1250, 1500, 1750, 2000, 2500, 3000, 3500, 4000, 4500, or 5000 μm). 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.
Referring again to the cover articles 100 of the disclosure, as depicted in exemplary form in
The cover articles 100, as depicted in exemplary form in
An exemplary article incorporating any of the cover articles disclosed herein is a wearable electronic device 300, as depicted in
Further, as shown in
Various embodiments will be further clarified by the following examples, as consistent with the cover articles depicted in
The refractive indices (as a function of wavelength) of each of the formed layers and the glass substrate were measured using spectroscopic ellipsometry in prior experiments. The refractive indices thus measured were then used to calculate reflectance spectra for the examples. The examples use a single refractive index value in their descriptive tables for convenience, which corresponds to a point selected from the dispersion curves at about 550 nm wavelength.
In the following examples, the articles exhibit an optimized, selected color or hue attribute (e.g., a red color in reflectance, etc.) with minimal color variation (e.g., low variation in Hue Angle (h*)) or an optimized hue (e.g., neutral grey in reflectance) with minimal hue variation (e.g., as given by a low Chroma (c*)<10) over a large range of viewing angles, and a combination of desirable mechanical properties (e.g., high hardness). The comparative articles, in contrast, may exhibit good mechanical properties, but they suffer from high color variation as a function of viewing angle.
A strengthened glass substrate was coated with the optical film structure of Table 1 below, designated Comp. Ex. 1. In particular, the optical film structure of Comp. Ex. 1 has a total of 13 layers with a total thickness of 2513.8 nm, including alternating high and low refractive index layers, a low RI layer in contact with the substrate (i.e., layer 13 with a thickness of 25.0 nm) and an oxide-containing capping layer at the outermost position of the stack (i.e., layer 1 with a thickness of 88.5 nm).
Referring to
A strengthened glass substrate was coated with the optical film structure of Table 1A below, designated Comp. Ex. 2. In particular, the optical film structure of Comp. Ex. 2 has a total of 11 layers with a total thickness of 2598.2 nm, including alternating high and low refractive index layers, a low RI layer in contact with the substrate (i.e., layer 11 with a thickness of 25.0 nm) and an oxide-containing capping layer at the outermost position of the stack (i.e., layer 1 with a thickness of 78.2 nm).
Referring to
A strengthened glass substrate was coated with the optical film structure of Table 2 below, designated Ex. 1. In particular, the optical film structure of Ex. 1 has a total of 13 layers with a total thickness of 3583.57 nm, including alternating high and low refractive index layers, a low RI layer in contact with the substrate (i.e., layer 13 with a thickness of 25.0 nm) and an oxide-containing capping layer at the outermost position of the stack (i.e., layer 1 with a thickness of 223.50 nm).
Referring to
Referring to
A strengthened glass substrate was coated with the optical film structure of Table 3 below, designated Ex. 2. In particular, the optical film structure of Ex. 2 has a total of 9 layers with a total thickness of 2684.76 nm, including alternating high and low refractive index layers, a low RI layer in contact with the substrate (i.e., layer 9 with a thickness of 25.0 nm) and an oxide-containing capping layer at the outermost position of the stack (i.e., layer 1 with a thickness of 82.87 nm).
Referring to
Referring to
A strengthened glass substrate was coated with the optical film structure of Table 4 below, designated Ex. 3. In particular, the optical film structure of Ex. 3 has a total of 17 layers with a total thickness of 3212.53 nm, including alternating high and low refractive index layers, a low RI layer in contact with the substrate (i.e., layer 17 with a thickness of 25.0 nm) and an oxide-containing capping layer at the outermost position of the stack (i.e., layer 1 with a thickness of 85.47 nm).
Referring to
Referring to
A strengthened glass substrate was coated with the optical film structure of Table 5 below, designated Ex. 4. In particular, the optical film structure of Ex. 4 has a total of 17 layers with a total thickness of 2884.04 nm, including alternating high and low refractive index layers, a low RI layer in contact with the substrate (i.e., layer 17 with a thickness of 25.0 nm) and an oxide-containing capping layer at the outermost position of the stack (i.e., layer 1 with a thickness of 124.93 nm).
Referring to
Referring to
A strengthened glass substrate was coated with the optical film structure of Table 6 below, designated Ex. 4A. In particular, the optical film structure of Ex. 4A has a total of 17 layers with a total thickness of 2784.11 nm, including alternating high and low refractive index layers, a low RI layer in contact with the substrate (i.e., layer 17 with a thickness of 25.0 nm) and an oxide-containing capping layer at the outermost position of the stack (i.e., layer 1 with a thickness of 25.0 nm). As compared to the cover article of Ex. 4, the cover article in this example (Ex. 4A) possesses a thinner capping layer (25 nm vs. 125 nm), which tends to improve hardness while maintaining strong color performance (e.g., color constancy).
Referring to
Referring to
A strengthened glass-ceramic substrate was coated with the optical film structure of Table 7 below, designated Ex. 4B. In particular, the optical film structure of Ex. 4B has a total of 17 layers with a total thickness of 2884.04 nm, including alternating high and low refractive index layers, a low RI layer in contact with the substrate (i.e., layer 17 with a thickness of 25.0 nm) and an oxide-containing capping layer at the outermost position of the stack (i.e., layer 1 with a thickness of 124.93 nm). As compared to the cover article of Ex. 4, the cover article in this example (Ex. 4B) possesses a strengthened glass-ceramic substrate, while the optical film structures of these examples remain the same.
Referring to
A strengthened glass substrate was coated with the optical film structure of Table 8 below, designated Ex. 5. In particular, the optical film structure of Ex. 5 has a total of 13 layers with a total thickness of 2685.75 nm, including alternating high and low refractive index layers, a low RI layer in contact with the substrate (i.e., layer 13 with a thickness of 25.0 nm) and an oxide-containing capping layer at the outermost position of the stack (i.e., layer 1 with a thickness of 25.0 nm).
Referring to
Referring to
Further, referring to
A strengthened glass substrate was coated with the optical film structure of Table 9 below, designated Ex. 6. In particular, the optical film structure of Ex. 6 has a total of 7 layers with a total thickness of 624.29 nm, including alternating high and low refractive index layers, a low RI layer in contact with the substrate (i.e., layer 7 with a thickness of 25.0 nm) and an oxide-containing capping layer at the outermost position of the stack (i.e., layer 1 with a thickness of 81.52 nm). Further, the optical film structure in Ex. 6 has a total of 56.21% high index material.
Referring to
Referring to
A strengthened glass substrate was coated with the optical film structure of Table 10 below, designated Ex. 7. In particular, the optical film structure of Ex. 7 has a total of 5 layers with a total thickness of 636.94 nm, including alternating high and low refractive index layers, a low RI layer in contact with the substrate (i.e., layer 5 with a thickness of 25.0 nm) and an oxide-containing capping layer at the outermost position of the stack (i.e., layer 1 with a thickness of 92.27 nm). Further, the optical film structure in Ex. 7 has a total of 76.23% high index material.
Referring to
Referring to
A strengthened glass substrate was coated with the optical film structure of Table 11 below, designated Ex. 8. In particular, the optical film structure of Ex. 8 has a total of 7 layers with a total thickness of 686.55 nm, including alternating high and low refractive index layers, a low RI layer in contact with the substrate (i.e., layer 7 with a thickness of 25.0 nm) and an oxide-containing capping layer at the outermost position of the stack (i.e., layer 1 with a thickness of 12.62 nm). Further, the optical film structure in Ex. 8 has a total of 64.51% high index material.
Referring to
Referring to
A strengthened glass substrate was coated with the optical film structure of Table 12 below, designated Ex. 9. In particular, the optical film structure of Ex. 9 has a total of 7 layers with a total thickness of 458.83 nm, including alternating high and low refractive index layers, a low RI layer in contact with the substrate (i.e., layer 7 with a thickness of 25.25 nm) and an oxide-containing capping layer at the outermost position of the stack (i.e., layer 1 with a thickness of 8.00 nm). Further, the optical film structure in Ex. 9 has a total of 71.13% high index material.
Referring to
Referring to
A strengthened glass substrate was coated with the optical film structure of Table 13 below, designated Ex. 9A. In particular, the optical film structure of Ex. 9A has a total of 7 layers with a total thickness of 458.83 nm, including alternating high and low refractive index layers, a low RI layer in contact with the substrate (i.e., layer 7 with a thickness of 25.25 nm) and an oxide-containing capping layer at the outermost position of the stack (i.e., layer 1 with a thickness of 8.0 nm). As compared to the cover article of Ex. 9, the cover article in this example (Ex. 9A) possesses a strengthened glass-ceramic substrate, while the optical film structures of these examples remain the same.
Referring to
A strengthened glass substrate was coated with the optical film structure of Table 14 below, designated Ex. 10. In particular, the optical film structure of Ex. 10 has a total of 7 layers with a total thickness of 679.7 nm, including alternating high and low refractive index layers, a low RI layer in contact with the substrate (i.e., layer 7 with a thickness of 25.0 nm) and an oxide-containing capping layer at the outermost position of the stack (i.e., layer 1 with a thickness of 65.18 nm).
Referring to
Referring to
Further, referring to
Optical and mechanical properties are summarized below in Tables 15A-15E for Exs. 1-10. Tables 15A-C below show selected reflectance attributes of the cover article and optical film structures of the preceding examples. Of these metrics, some of the most important to note are the normal incidence (0 degree) Chroma (c*) value, the normal incidence Hue Angle (h*) value, and the variation in Hue Angle (h*) (“delta h*”) over viewing angle ranges from 0-30, 0-60, and 0-90 degrees. Color metrics listed in Tables 15A-C are for first-surface (surface of substrate with optical film structure) reflectance, unless otherwise noted. Further, unless otherwise noted, all color values are reported using the CIE D65 illuminant.
With further regard to Tables 15A-C below, normal incident color coordinates are provided with max Chroma (c*), Hue Angle (h*), and calculated saturation (s*). Also provided are particularly attractive performance parameters of these designs showing minimal variance in Hue Angle in different ranges of incident viewing angles. In addition, the silver and grey designs (Exs. 5 and 10) have very low max Chroma (c*) values. In contrast to the other color designs (Exs. 1-4 and 6-9), low max Chroma (c*) is of higher importance than Hue Angle (h*) for the designs that target a silver or grey hue.
The top six examples in these tables are cover articles consistent with the designs detailed earlier and depicted in
Transmittance properties for the cover article examples (Exs. 1-10) are provided below in Table 15D. Normal incident color coordinates are provided with max Chroma (c*), Hue Angle (h*), and calculated saturation (s*). The top six examples in these tables are cover articles consistent with the designs detailed earlier and depicted in
Mechanical properties for the cover article examples (Exs. 1-10) are provided below in Table 15E. The cover article designs consistent with those depicted in
The various features described in the specification may be combined in any and all combinations, for example, as listed in the following embodiments. It should also be appreciated that in the above embodiments, if desired, the B-side (i.e., the inner primary surface 114) of the substrate 110 may comprise a surface treatment to provide additional, desired appearance(s). For example, these surface treatments can include as-engineered surface roughness levels, additional dielectric layer(s) and/or ink layer(s).
Embodiment 1. A cover article is provided that includes: a substrate comprising an outer primary surface and an inner primary surface, the outer and inner primary surfaces are opposite of one another; and an optical film structure comprising an outermost surface disposed on the outer or inner primary surface of the substrate. The optical film structure comprises a plurality of alternating high refractive index and low refractive index layers. Each of the high refractive index layers has a refractive index greater than a refractive index of each of the low refractive index layers. Further, the cover article exhibits a substantially constant hue in reflectance with a D65 illuminant, as given by an exhibited color with a variation in Hue Angle (h*) of less than 50 degrees over a viewing angle range from 0 to 60 degrees.
Embodiment 2. The cover article of Embodiment 1 is provided, wherein the cover article exhibits a substantially constant hue in reflectance with a D65 illuminant, as given by an exhibited color with a variation in Hue Angle (h*) of less than 225 degrees over a viewing angle range from 0 to 90 degrees.
Embodiment 3. The cover article of Embodiment 1 or Embodiment 2 is provided, wherein the cover article exhibits a substantially constant hue in reflectance with a D65 illuminant, as given by an exhibited color with a variation in Hue Angle (h*) of less than 15 over a viewing angle range from 0 to 30 degrees.
Embodiment 4. The cover article of any one of Embodiments 1-3 is provided, wherein the cover article exhibits an average photopic transmittance of greater than 60% at a normal viewing angle of about 0 degrees.
Embodiment 5. The cover article of any one of Embodiments 1-4 is provided, wherein the cover article exhibits a substantially constant hue in reflectance with a D65 illuminant, as given by an exhibited pink or red color with a Hue angle (h*) of from 320 degrees to 40 degrees and a Chroma (c*) of greater than 15.
Embodiment 6. The cover article of any one of Embodiments 1-4 is provided, wherein the cover article exhibits a substantially constant hue in reflectance with a D65 illuminant, as given by an exhibited yellow color with a Hue angle (h*) of from 40 degrees to 135 degrees and a Chroma (c*) of greater than 15.
Embodiment 7. The cover article of any one of Embodiments 1-4 is provided, wherein the cover article exhibits a substantially constant hue in reflectance with a D65 illuminant, as given by an exhibited green color with a Hue angle (h*) of from 135 degrees to 200 degrees and a Chroma (c*) of greater than 15.
Embodiment 8. The cover article of any one of Embodiments 1-4 is provided, wherein the cover article exhibits a substantially constant hue in reflectance with a D65 illuminant, as given by an exhibited blue or purple color with a Hue angle (h*) of from 200 degrees to 320 degrees and a Chroma (c*) of greater than 15.
Embodiment 9. A cover article is provided that includes: a substrate comprising an outer primary surface and an inner primary surface, wherein the outer and inner primary surfaces are opposite of one another; and an optical film structure comprising an outermost surface disposed on the outer or inner primary surface of the substrate. The optical film structure comprises a plurality of alternating high refractive index and low refractive index layers. Each of the high refractive index layers has a refractive index greater than a refractive index of each of the low refractive index layers. The optical film structure has a physical thickness that ranges from 1000 nm to 4000 nm. One of the high refractive index layers is a scratch resistant layer having a physical thickness from 500 nm to 3000 nm. One of the low refractive index layers is a capping layer disposed over the scratch resistant layer. A portion of the plurality of alternating high refractive index and low refractive index layers is between the scratch resistant layer and the substrate. The optical film structure exhibits a hardness of at least 12 GPa, as measured with a Berkovich Indenter Hardness Test from the outermost surface of the optical film structure to a depth from about 100 nm to about 300 nm. Further, the cover article exhibits a substantially constant hue in reflectance with a D65 illuminant, as given by an exhibited color with a variation in Hue Angle (h*) of less than 50 degrees over a viewing angle range from 0 to 60 degrees.
Embodiment 10. The cover article of Embodiment 9 is provided, wherein the cover article exhibits a substantially constant hue in reflectance with a D65 illuminant, as given by an exhibited color with a variation in Hue Angle (h*) of less than 20 degrees over a viewing angle range from 0 to 60 degrees.
Embodiment 11. The cover article of Embodiment 10 is provided, wherein the scratch resistant layer is a nitride or an oxyntride and has a physical thickness from 800 nm to 2500 nm, and wherein the capping layer is an oxide.
Embodiment 12. The cover article of any one of Embodiments 9-11 is provided, wherein the capping layer is in contact with the scratch resistant layer, is the outermost layer of the optical film structure, and has a physical thickness of from 20 nm to 250 nm.
Embodiment 13. The cover article of any one of Embodiments 9-11 is provided, wherein the capping layer is the only layer over the scratch resistant layer with a physical thickness of greater than 20 nm.
Embodiment 14. The cover article of any one of Embodiments 9-13 is provided, wherein one of the low refractive index layers is in contact with the outer or inner primary surface of the substrate, and the optical film structure comprises 5 to 19 layers.
Embodiment 15. The cover article of any one of Embodiments 9-14 is provided, wherein the cover article exhibits a substantially constant hue in reflectance with a D65 illuminant, as given by an exhibited pink or red color with a Hue angle (h*) of from 320 degrees to 40 degrees and a Chroma (c*) of greater than 15.
Embodiment 16. The cover article of any one of Embodiments 9-14 is provided, wherein the cover article exhibits a substantially constant hue in reflectance with a D65 illuminant, as given by an exhibited yellow color with a Hue angle (h*) of from 40 degrees to 135 degrees and a Chroma (c*) of greater than 15.
Embodiment 17. The cover article of any one of Embodiments 9-14 is provided, wherein the cover article exhibits a substantially constant hue in reflectance with a D65 illuminant, as given by an exhibited green color with a Hue angle (h*) of from 135 degrees to 200 degrees and a Chroma (c*) of greater than 15.
Embodiment 18. The cover article of any one of Embodiments 9-14 is provided, wherein the cover article exhibits a substantially constant hue in reflectance with a D65 illuminant, as given by an exhibited blue or purple color with a Hue angle (h*) of from 200 degrees to 320 degrees and a Chroma (c*) of greater than 15.
Embodiment 19. A cover article is provided that includes: a substrate comprising an outer primary surface and an inner primary surface, wherein the outer and inner primary surfaces are opposite of one another; and an optical film structure comprising an outermost surface disposed on the outer or inner primary surface of the substrate. The optical film structure comprises a plurality of alternating high refractive index and low refractive index layers. Each of the high refractive index layers has a refractive index greater than a refractive index of each of the low refractive index layers. The optical film structure has a physical thickness that ranges from 250 nm to 1000 nm. The optical film structure exhibits a hardness of at least 8 GPa, as measured with a Berkovich Indenter Hardness Test from the outermost surface of the optical film structure to a depth from about 100 nm to about 300 nm. Further, the cover article exhibits a substantially constant hue in reflectance with a D65 illuminant, as given by an exhibited color with a variation in Hue Angle (h*) of less than 50 degrees over a viewing angle range from 0 to 60 degrees.
Embodiment 20. The cover article of Embodiment 19 is provided, wherein each of the high refractive index layers is a nitride or an oxyntride and the low refractive index layers is an oxide.
Embodiment 21. The cover article of Embodiment 19 or Embodiment 20 is provided, wherein one of the low refractive index layers is in contact with the outer or inner primary surface of the substrate, and the optical film structure comprises 5 to 12 layers.
Embodiment 22. The cover article of any one of Embodiments 19-21 is provided, wherein the high refractive index layers collectively comprise greater than 50% of the volume or physical thickness of the optical film structure.
Embodiment 23. The cover article of any one of Embodiments 19-22 is provided, wherein the cover article exhibits a substantially constant hue in reflectance with a D65 illuminant, as given by an exhibited pink or red color with a Hue angle (h*) of from 320 degrees to 40 degrees and a Chroma (c*) of greater than 15.
Embodiment 24. The cover article of any one of Embodiments 19-22 is provided, wherein the cover article exhibits a substantially constant hue in reflectance with a D65 illuminant, as given by an exhibited yellow color with a Hue angle (h*) of from 40 degrees to 135 degrees and a Chroma (c*) of greater than 15.
Embodiment 25. The cover article of any one of Embodiments 19-22 is provided, wherein the cover article exhibits a substantially constant hue in reflectance with a D65 illuminant, as given by an exhibited green color with a Hue angle (h*) of from 135 degrees to 200 degrees and a Chroma (c*) of greater than 15.
Embodiment 26. The cover article of any one of Embodiments 19-22 is provided, wherein the cover article exhibits a substantially constant hue in reflectance with a D65 illuminant, as given by an exhibited blue or purple color with a Hue angle (h*) of from 200 degrees to 320 degrees and a Chroma (c*) of greater than 15.
Embodiment 27. A cover article is provided that includes: a substrate comprising an outer primary surface and an inner primary surface, wherein the outer and inner primary surfaces are opposite of one another; and an optical film structure comprising an outermost surface disposed on the outer or inner primary surface of the substrate. The optical film structure comprises a plurality of alternating high refractive index and low refractive index layers. Each of the high refractive index layers has a refractive index greater than a refractive index of each of the low refractive index layers. Further, the cover article exhibits a substantially neutral color in reflectance with a D65 illuminant, as given by an exhibited grey hue or silver hue, each with a Chroma (c*) of less than 10.
Embodiment 28. The cover article of Embodiment 27 is provided, the cover article exhibits a substantially neutral color in reflectance with a D65 illuminant, as given by an exhibited grey hue or silver hue, each with a Chroma (c*) of less than 5.
Embodiment 29. The cover article of any one of Embodiments 26-27 is provided, wherein the optical film structure has a physical thickness that ranges from 1000 nm to 4000 nm, one of the high refractive index layers is a scratch resistant layer having a physical thickness from 500 nm to 3000 nm, one of the low refractive index layers is a capping layer disposed over the scratch resistant layer, a portion of the plurality of alternating high refractive index and low refractive index layers is between the scratch resistant layer and the substrate, and the optical film structure exhibits a hardness of at least 12 GPa, as measured with a Berkovich Indenter Hardness Test from the outermost surface of the optical film structure to a depth from about 100 nm to about 300 nm.
Embodiment 30. The cover article of any one of Embodiments 26-27 is provided, wherein the optical film structure has a physical thickness that ranges from 250 nm to 1000 nm, and the optical film structure exhibits a hardness of at least 8 GPa, as measured with a Berkovich Indenter Hardness Test from the outermost surface of the optical film structure to a depth from about 100 nm to about 300 nm.
This application claims the benefit of priority under 35 U.S.C. § 119 of U.S. Provisional Application No. 63/455,670 filed Mar. 30, 2023. The entire contents of this application are hereby incorporated herein by reference for all purposes.
| Number | Date | Country | |
|---|---|---|---|
| 63455670 | Mar 2023 | US |
