Textured glass articles and methods of making the same

Abstract

A textured glass article, comprising: a body comprising an alumino-silicate glass comprising greater than or equal to 16 weight percent Al2O3 and a ratio of Al2O3 / SiO2 less than or equal to 0.3, the body having at least a first surface; a plurality of polyhedral surface features extending from the first surface, each polyhedral surface feature of the plurality of polyhedral surface features comprising: a base on the first surface, a plurality of facets extending from the first surface, and a surface feature size at the base greater than or equal to 10 pm and less than or equal to 100 pm, wherein the plurality of facets of each polyhedral surface feature converge toward one another; and a transmission haze greater than or equal to 50 percent.

Description

[0001] Cross-reference of related applications

[0002] This specification claims priority to U.S. Provisional Application No. 63 / 074,761, filed September 4, 2020, entitled “Textured Glass Articles and Methods of Manufacturing Thereof,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] In general, this application relates to glass articles, and more specifically, to glass articles having a highly reflective appearance and / or an enhanced tactile feel. Background Technology

[0004] Aluminosilicate glass products exhibit excellent ion exchange capacity and drop resistance. Various industries, including consumer electronics, desire reflective and / or textured materials with similar or identical strength and fracture toughness. However, conventional texturing processes may not produce the desired appearance and / or texture on certain aluminosilicate glass products.

[0005] Therefore, alternative methods are needed to produce aluminosilicate glass products with a highly reflective appearance and / or improved tactile feel. Summary of the Invention

[0006] According to the first aspect A1, a textured glass article may include: a body comprising aluminosilicate glass containing greater than or equal to 16% by weight of Al2O3 and less than or equal to 0.3 of an Al2O3 / SiO2 ratio, the body having at least a first surface; a plurality of polyhedral surface features extending from the first surface, each of the plurality of polyhedral surface features comprising: a base located on the first surface, a plurality of facets extending from the first surface, and a surface feature size of greater than or equal to 10 μm and less than or equal to 100 μm located at the base, wherein the plurality of facets of each polyhedral surface feature converge toward each other; and a transmission haze of greater than or equal to 50%.

[0007] The second aspect A2 includes a textured glass article according to the first aspect A1, wherein the plurality of facets of each polyhedral surface feature converge toward each other to form at least one vertex, said at least one vertex being sharp, rounded, or truncated.

[0008] The third aspect A3 includes a textured glass article according to the first aspect A1 or the second aspect A2, wherein the textured glass article has a surface roughness Ra greater than or equal to 1 μm.

[0009] A fourth aspect A4 includes the textured glass article of any of the first through third aspects Al through A3, wherein the base of each polyhedral surface feature of the plurality of polyhedral surface features comprises at least three edges, at least one edge converging toward at least another edge.

[0010] A fifth aspect A5 includes the textured glass article of any of the first through fourth aspects Al through A4, wherein each polyhedral surface feature of the plurality of polyhedral surface features comprises a dendritic structure extending from the base.

[0011] A sixth aspect A6 includes the textured glass article of any of the first through fifth aspects Al through A5, wherein the textured glass article has a peak maximum (peak GU) greater than or equal to 50 GU and less than or equal to 150 GU.

[0012] A seventh aspect A7 includes the textured glass article of any of the first through sixth aspects Al through A6, wherein the textured glass article has a full width at half maximum greater than or equal to 10 GU and less than or equal to 70 GU.

[0013] An eighth aspect A8 includes the textured glass article of any of the first through seventh aspects Al through A7, wherein the textured glass article has a range of GU values greater than or equal to 100 GU and less than or equal to 300 GU.

[0014] A ninth aspect A9 includes the textured glass article of any of the first through eighth aspects Al through A8, wherein the textured glass article has a skewness greater than or equal to 0.05 and less than or equal to 0.7.

[0015] A tenth aspect A10 includes the textured glass article of any of the first through ninth aspects Al through A9, wherein the textured glass article has an excess kurtosis greater than or equal to 0.5 and less than or equal to 3.

[0016] Eleventh aspect A11 includes the textured glass article of any of the first through tenth aspects Al through A10, wherein the textured glass article comprises: greater than or equal to 52 weight percent and less than or equal to 67 weight percent Si02; greater than or equal to 16 weight percent and less than or equal to 28 weight percent Al203; greater than or equal to 0 weight percent and less than or equal to 5 weight percent B203; greater than or equal to 8 weight percent and less than or equal to 15 weight percent Na20; greater than or equal to 0 weight percent and less than or equal to 0.2 weight percent K20; greater than or equal to 0 weight percent and less than or equal to 4 weight percent Li20; and greater than or equal to 0 weight percent and less than or equal to 5 weight percent MgO.

[0017] Twelfth aspect A12 includes the textured glass article of any of the first through eleventh aspects Al through Al l, wherein the textured glass article is a back cover for an electronic device.

[0018] According to thirteenth aspect A13, a textured glass article can comprise: a body comprising an aluminosilicate glass comprising greater than or equal to 16 weight percent Al203and an Al203 / Si02ratio of greater than 0.3, the body having at least a first surface; a plurality of dendritic surface features extending from the first surface, each of the plurality of dendritic surface features comprising a base on the first surface and a surface feature size at the base of greater than 100 pm and less than or equal to 350 pm; and a transmission haze of greater than or equal to 50 percent.

[0019] Fourteenth aspect A14 includes the textured glass article of the thirteenth aspect A13, wherein the textured glass article has a surface roughness Ra of greater than or equal to 2 pm.

[0020] Fifteenth aspect A15 includes the textured glass article of the thirteenth aspect A13 or the fourteenth aspect A14, wherein the aluminosilicate glass comprises: greater than or equal to 52 weight percent and less than or equal to 62 weight percent Si02; greater than or equal to 16 weight percent and less than or equal to 28 weight percent Al203; greater than or equal to 0 weight percent and less than or equal to 5 weight percent B203; greater than or equal to 8 weight percent and less than or equal to 13 weight percent Na20; greater than or equal to 0 weight percent and less than or equal to 0.2 weight percent K20; greater than or equal to 0 weight percent and less than or equal to 4 weight percent Li20; and greater than or equal to 0 weight percent and less than or equal to 1.5 weight percent MgO.

[0021] Sixteenth aspect A16 includes the textured glass article of any of the thirteenth through fifteenth aspects A13 through A15, wherein the textured glass article is a back cover for an electronic device.

[0022] According to a seventeenth aspect A17, a method of forming a textured glass article can include the steps of: contacting an aluminosilicate glass article with an etchant, wherein the aluminosilicate glass article includes greater than or equal to 16 wt% AI2O3 and has at least one surface, and the etchant includes a pH less than or equal to 3.0; rinsing the aluminosilicate glass article; and drying the aluminosilicate glass article to form a textured glass article including a plurality of surface features extending from a first surface of the textured glass article, each surface feature of the plurality of surface features including a base positioned on the first surface, and a surface feature size at the base greater than or equal to 10 pm and less than or equal to 350 pm, wherein the textured glass article has a transmittance haze greater than or equal to 50%.

[0023] An eighteenth aspect A18 includes the method according to the seventeenth aspect A17, wherein the aluminosilicate glass article includes an AI2O3 / SiO2 ratio less than or equal to 0.3, wherein the plurality of surface features are polyhedral surface features, and wherein the surface feature size at the base is greater than or equal to 10 pm and less than or equal to 100 pm.

[0024] A nineteenth aspect A19 includes the method according to the eighteenth aspect A18, wherein contacting the aluminosilicate glass article with the etchant results in more silicon-based precipitates than aluminum-based precipitates.

[0025] A twentieth aspect A20 includes the method according to the seventeenth aspect A17, wherein the aluminosilicate glass article includes an AI2O3 / SiO2 ratio greater than 0.3, wherein the plurality of surface features are dendritic surface features, and wherein the surface feature size at the base is greater than 100 pm and less than or equal to 350 pm.

[0026] A twenty-first aspect A21 includes the method according to the twentieth aspect A20, wherein contacting the aluminosilicate glass article with the etchant results in more aluminum-based precipitates than silicon-based precipitates.

[0027] A twenty-second aspect A22 includes the method according to any one of aspects A17-A21, wherein the etchant includes: greater than or equal to 20 wt% and less than or equal to 40 wt% of a salt; and greater than or equal to 30 wt% and less than or equal to 65 wt% of an acid.

[0028] A twenty-third aspect A23 includes the method according to the twenty-second aspect A22, wherein the salt includes: ammonium chloride, ammonium fluoride, ammonium bifluoride, ammonium sulfate, ammonium nitrate, potassium sulfate, potassium chloride, potassium fluoride, potassium bifluoride, potassium nitrate, sodium chloride, sodium fluoride, sodium bifluoride, or a combination thereof.

[0029] The twenty-fourth aspect A24 includes the method of the twenty-second aspect A22 or the twenty-third aspect A23, wherein the acid comprises: hydrochloric acid, hydrofluoric acid, nitric acid, sulfuric acid, oxalic acid, acetic acid, sodium bisulfate, or a combination thereof.

[0030] The twenty-fifth aspect A25 includes the method of any one of the seventeenth through twenty-fourth aspects A17-A24, wherein the etchant comprises: greater than or equal to 20 wt.% and less than or equal to 40 wt.% ammonium fluoride; greater than or equal to 25 wt.% and less than or equal to 45 wt.% nitric acid; greater than or equal to 5 wt.% and less than or equal to 20 wt.% hydrofluoric acid; and greater than or equal to 20 wt.% and less than or equal to 40 wt.% water.

[0031] The twenty-sixth aspect A26 includes a consumer electronic device, comprising: a housing having a front surface, a back surface, and side surfaces; and electrical components at least partially located within the housing, the electrical components comprising at least a controller, a memory, and a display, the display disposed at or near the front surface of the housing; wherein the back surface of the housing comprises the textured glass article of the first aspect Al.

[0032] Additional features and advantages of the textured glass articles described herein will be set forth in the detailed description that follows, and in part will be apparent to those skilled in the art upon examination of the description, or can be learned by practice of the embodiments described herein, including the detailed description and claims that follow, the drawings that are described below, and the appended claims.

[0033] It is to be understood that both the foregoing general description and the following detailed description describe various embodiments, and are intended to provide an overview or framework for understanding the nature and character of the claimed subject matter. The accompanying drawings are included to provide a further understanding of the various embodiments, and are incorporated in and constitute a part of this specification. The drawings illustrate various embodiments described herein, and, together with the description, serve to explain principles and operations of the claimed subject matter. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 schematically depicts a perspective view of a textured glass article according to one or more embodiments shown and described herein;

[0035] Figure 2 schematically depicts a plan view of a textured glass article according to one or more embodiments shown and described herein;

[0036] Figure 3 schematically depicts a perspective view of a textured glass article according to one or more embodiments shown and described herein;

[0037] Figure 4 schematically depict plan views of textured glass articles according to one or more embodiments shown and described herein;

[0038] Figure 5 a flow chart of a method of forming a textured glass article according to one or more embodiments described herein;

[0039] Figure 6 schematically depict steps of an etching process according to one or more embodiments shown and described herein;

[0040] Figure 7 schematically depict another step of an etching process according to one or more embodiments shown and described herein;

[0041] Figure 8 schematically depict another step of an etching process according to one or more embodiments shown and described herein;

[0042] Figure 9 schematically depict another step of an etching process according to one or more embodiments shown and described herein;

[0043] Figure 10 a plan view of an example electronic device including any of the textured glass articles according to one or more embodiments shown and described herein;

[0044] Figure 11 a perspective view of an example electronic device; Figure 10

[0045] Figure 12 a perspective view of an example electronic device; Figure 10

[0046] Figure 13 a confocal image of a textured glass article according to one or more embodiments shown and described herein at 50x magnification;

[0047] Figure 14 a confocal image of a textured glass article according to one or more embodiments shown and described herein at 50x magnification;

[0048] Figure 15 a confocal image of a textured glass article according to one or more embodiments shown and described herein at 50x magnification;

[0049] Figure 16 an XRD spectrum of a textured glass article according to one or more embodiments shown and described herein;

[0050] Figure 17 ​​a confocal image of a textured glass article according to one or more embodiments shown and described herein at 50x magnification;

[0051] Figure 18 a confocal image of a textured glass article according to one or more embodiments shown and described herein at 50x magnification; and

[0052] Figure 19 an XRD spectrum of a textured glass article according to one or more embodiments shown and described herein. DETAILED DESCRIPTION

[0053] Reference will now be made in detail to various embodiments of textured glass articles having a high-reflective appearance and / or enhanced tactile feel. According to embodiments, a textured glass article includes a body comprising an aluminosilicate glass comprising greater than or equal to 16 wt.% AI2O3 and a ratio of AI2O3 / SiO2 less than or equal to 0.3, the body having at least a first surface; a plurality of polyhedral surface features extending from the first surface, each polyhedral surface feature of the plurality of polyhedral surface features comprising a base on the first surface, a plurality of facets extending from the first surface, and a surface feature size at the base greater than or equal to 10 pm and less than or equal to 100 pm, wherein the plurality of facets of each polyhedral surface feature converge toward one another; and a transmission haze greater than or equal to 50%. According to other embodiments, a textured glass article includes a body comprising an aluminosilicate glass comprising greater than or equal to 16 wt.% AI2O3 and a ratio of AI2O3 / SiO2 greater than 0.3, the body having at least a first surface; a plurality of dendritic surface features extending from the first surface, each dendritic surface feature of the plurality of dendritic surface features comprising a base on the first surface, and a surface feature size at the base greater than 100 pm and less than or equal to 350 pm, wherein the plurality of facets of each polyhedral surface feature converge toward one another; and a transmission haze greater than or equal to 60%. Various embodiments of textured glass articles and methods of making the same will be described herein with specific reference to the drawings.

[0054] Ranges can be expressed herein as "about" one particular value and / or "about" another particular value. When such ranges are 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 each endpoint is of a meaningful

[0055] Directional terms as used herein for example up, down, right, left, front, back, top, bottom, refer to the orientation of the figure shown and are not to be construed as limiting absolute orientations.

[0056] Unless explicitly stated otherwise, no method set forth herein is intended to require its steps to be performed in a particular order, nor is it necessary that any device be constructed in a particular order. Accordingly, where a method claim does not actually recite a step as being performed before, after, or concurrent with another step, it is not to be implied that the steps are order-dependent. It is further noted that any possible patentable application is intended to cover all combinations of variations of the technology described herein including combinations that do not specifically appear in the claims or embodiments set forth above. It is intended to include alternatives, modifications, improvements, equivalents, and substantial equivalents of what is specifically disclosed herein. It is intended that the application that is described herein include all such alternatives, modifications, improvements, equivalents, and substantial equivalents. All such alternatives, modifications, improvements, equivalents, and substantial equivalents are intended to be within the scope of the claims.

[0057] As used herein the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a component" includes aspects with two or more such components unless the context clearly indicates otherwise.

[0058] In embodiments of the glass compositions described herein, concentrations of constituent components (e.g., Si02, AI2O3, etc.) are specified in terms of weight percent (wt.%) of the oxides, unless otherwise indicated.

[0059] X-ray diffraction (XRD) spectra as described herein were measured using a D8 ENDEAVOR X-ray diffractometer system with a LYNXEYE XE-T detector manufactured by Bruker Corporation [Billerica, MA].

[0060] Confocal images as described herein were obtained using a Leica DCM8 microscope, plus associated Leica SCAN software package, at 50x magnification. Confocal images were used to measure surface feature size and surface roughness of the textured glass articles. Transmission haze, transmission, and 450 nm reflectance of the textured glass articles were analyzed using a Ci7800 spectrometer provided by Pantone x-Rite, plus associated iColor analysis program.

[0061] “Surface feature size” refers to the average longest dimension across the cross-section of the base of the 10 largest surface features at three different locations in the confocal image. Thus, the longest dimension of the 10 largest surface features at different locations is measured. The average of the 30 feature size measurements is calculated to obtain the surface feature size of the textured glass article.

[0062] “Surface roughness (‘Ra’)” as described herein refers to the surface texture of a textured glass article quantified by the arithmetic average of the absolute values of the profile height deviations from the mean line, recorded over an evaluation length. Values reported herein are reported in microns or pm, unless explicitly stated otherwise.

[0063] “Transmission haze” as described herein refers to the ratio of the transmitted light scattered at angles greater than 2.5° from the normal to the total transmission of all transmitted light. Unless explicitly stated otherwise, transmission haze as described herein is measured at a thickness of 0.8 mm over a wavelength range of 360 nm to 750 nm.

[0064] “Transmittance” as used herein refers to the average transmittance accomplished over a given wavelength range. In the embodiments described herein, unless explicitly stated otherwise, “transmittance” is reported at a thickness of 0.8 mm over a wavelength range of 360 nm to 750 nm.

[0065] “450 nm reflectance” as used herein, unless explicitly stated otherwise, refers to the reflectance accomplished at a thickness of 0.8 mm at a wavelength of 450 nm.

[0066] “Surface feature height” as described herein refers to the distance between the base of a surface feature and the highest apex of the surface feature.

[0067] “Facet angle” as described herein refers to the angle between a plane normal to the first surface of the aluminosilicate glass article and a facet. The facet angle is measured from the arctangent (height / half-length) of a surface feature.

[0068] The grayscale distributions described herein were collected by illuminating the article with a high intensity white LED [Metaphaser LED light engine by Metaphase Technologies, Bristol, PA] coupled to a fiber optic light guide. The light reflected from the surface of the article was collected by a camera / lens combination [Stingray F-125B by Allied Vision Technologies Gmbh, Germany, and M112FM50 by Tamron Co., Ltd., Saitama, Japan]. The lens aperture was f / 2.8, the working distance was about 300 mm, the exposure time was 6 ms, and the gain setting was 0 db. The peak maximum position, full width at half maximum, range of peak maximum position, skewness, and excess kurtosis of the textured glass articles described herein (e.g., the resulting textured glass articles shown in Table 4) were calculated using the collected images.

[0069] "GU" as described herein refers to a grayscale unit.

[0070] "Peak maximum position ('peak GU')" as described herein and calculated from images collected from the reflected light of the surface of an article refers to the grayscale value at which the amplitude is maximized.

[0071] "Full width at half maximum ('FWHM')" as described herein and calculated from images collected from the reflected light of the surface of an article refers to the width of the curve measured between those points on the y-axis that are one-half of the maximum amplitude.

[0072] "Range of GU values" as described herein and calculated from images collected from the reflected light of the surface of an article refers to the difference between the highest grayscale value and the lowest grayscale value in a given image.

[0073] "Skewness" as described herein and calculated from images collected from the reflected light of the surface of an article refers to the asymmetry of a real-valued random variable distribution with respect to its mean. For example, the skewness of a normal distribution is equal to zero.

[0074] "Excess kurtosis" as described herein refers to the kurtosis minus 3 and is used to compare directly to the standard normal distribution kurtosis.

[0075] "Polyhedral" when used to describe the structure of surface features on a textured glass article refers to a three-dimensional shape having flat polygonal faces, straight edges.

[0076] "Dendritic" when used to describe the structure of surface features on a textured glass article refers to a branched structure.

[0077] "Nitric acid" as described herein refers to a stock solution of nitric acid having 70 wt.% nitric acid.

[0078] "Hydrofluoric acid" as described herein refers to a stock solution of hydrofluoric acid having 49 wt.% hydrofluoric acid.

[0079] Etchants have been used to achieve textured surfaces on glass articles. For example, aluminosilicate glasses that exhibit excellent ion exchange capabilities and drop performance can be etched to produce reflective and / or textured materials having the same or similar strength and fracture toughness properties. However, simply etching aluminosilicate glasses that include greater than or equal to 16 wt.% AI2O3 can not produce the desired reflective appearance and / or enhanced tactile feel.

[0080] Textured glass articles and methods of texturing that alleviate the aforementioned problems are disclosed herein such that aluminosilicate glasses that include greater than or equal to 16 wt.% AI2O3, which exhibit excellent ion exchange capabilities and drop performance, can be processed to produce the desired appearance and / or texture. In particular, the textured glass articles disclosed herein include aluminosilicate glasses having polyhedral surface features that provide a high reflective appearance or aluminosilicate glasses having dendritic surface features that provide an enhanced tactile feel.

[0081] To produce polyhedral surface features, aluminosilicate glass articles that include greater than or equal to 16 wt.% AI2O3 can have an AI2O3 / SiO2 ratio of less than or equal to 0.3 such that etchants having a pH of less than or equal to 3.0 preferentially produce silica-based precipitates that result in polyhedral surface features and minimize aluminum-based precipitates that result in dendritic surface features.

[0082] To produce dendritic surface features, aluminosilicate glass articles that include greater than or equal to 16 wt.% AI2O3 can have an AI2O3 / SiO2 ratio of greater than 0.3 such that etchants having a pH of less than 3 preferentially produce aluminum-based precipitates that result in dendritic surface features and minimize silica-based precipitates that result in polyhedral surface features.

[0083] Polyhedral surface features

[0084] See, for example, Figure 1 and Figure 2In embodiments, the textured glass article 100 described herein has a body 102 comprising an alumino-silicate glass comprising greater than or equal to 16 wt% AI2O3and a ratio of AI2O3 / SiO2less than or equal to 0.3. In embodiments, the alumino-silicate glass article can comprise: greater than or equal to 52 wt% and less than or equal to 67 wt% SiO2; greater than or equal to 16 wt% and less than or equal to 28 wt% AI2O3; greater than or equal to 0 wt% and less than or equal to 5 wt% B2O; greater than or equal to 8 wt% and less than or equal to 15 wt% Na2O; greater than or equal to 0 wt% and less than or equal to 0.2 wt% K2O; greater than or equal to 0 wt% and less than or equal to 4 wt% Li2O; and greater than or equal to 0 wt% and less than or equal to 5 wt% MgO. However, it should be understood that other alumino-silicate glasses can also be considered and are possible so long as the alumino-silicate glass has greater than or equal to 16 wt% AI2O3and a ratio of AI2O3 / SiO2less than or equal to 0.3.

[0085] The body 102 comprises at least a first surface 104. A plurality of polyhedral surface features 106 extend from the first surface 104. Each polyhedral surface feature 106 comprises a base 108 on the first surface 104, and a plurality of facets 110 extending from the first surface 104.

[0086] In embodiments, the facets 110 of each polyhedral surface feature 106 extend from the first surface 104 and converge toward one another to form a polyhedral morphology of the polyhedral surface feature 106 (e.g., a pyramid having 3-fold symmetry, 4-fold symmetry, 6-fold symmetry, etc.). In embodiments, the facets 110 of each polyhedral surface feature 106 converge toward one another at a facet angle greater than or equal to 0.5° and less than or equal to 12°. In embodiments, the facets 110 can be triangular, rectangular, or trapezoidal. In embodiments, the facets 110 converge to form at least one apex 112a, 112b, 112c. In embodiments, the apex can be a sharp apex 112a, a rounded apex 112b, or a truncated apex 112c.

[0087] The base 108 of each polyhedral surface feature 106 includes at least three edges 114. At least one edge 114 of the base 108 converges toward at least another edge 114. In embodiments, the base 108 can be triangular, rectangular, or hexagonal. In embodiments, the surface feature size at the base 108 can be greater than or equal to 10 pm and less than or equal to 100 pm. In embodiments, the surface feature size at the base 108 can be greater than or equal to 10 pm, greater than or equal to 25 pm, or even greater than or equal to 50 pm. In embodiments, the surface feature size at the base 108 can be less than or equal to 100 pm, less than or equal to 95, or even less than or equal to 90 pm. In embodiments, the surface feature size at the base 108 can be greater than or equal to 10 pm and less than or equal to 100 pm, greater than or equal to 10 pm and less than or equal to 95 pm, greater than or equal to 10 pm and less than or equal to 90 pm, greater than or equal to 25 pm and less than or equal to 100 pm, greater than or equal to 25 pm and less than or equal to 95 pm, greater than or equal to 25 pm and less than or equal to 90 pm, greater than or equal to 50 pm and less than or equal to 100 pm, greater than or equal to 50 pm and less than or equal to 95 pm, or even greater than or equal to 50 pm and less than or equal to 90 pm, or any and all sub-ranges formed by any of these endpoints.

[0088] In embodiments, the textured glass article 100 can have a surface roughness Ra that is greater than or equal to 1 pm or even greater than or equal to 1.5 pm. In embodiments, the textured glass article 100 can have a surface roughness Ra that is less than or equal to 2 pm or even less than or equal to 1.8 pm. In embodiments, the textured glass article 100 can have a surface roughness Ra that is greater than or equal to 1 pm and less than or equal to 2 pm, greater than or equal to 1 pm and less than or equal to 1.8 pm, greater than or equal to 1.5 pm and less than or equal to 2 pm, or even greater than or equal to 1.5 pm and less than or equal to 1.8 pm, or any and all sub-ranges formed by any of these endpoints.

[0089] The transmittance haze of the textured glass article 100 can be associated with the surface roughness Ra, i.e., a relatively greater transmittance haze can mean that the textured glass article 100 has a relatively greater surface roughness Ra. In embodiments, the textured glass article 100 can have a transmittance haze greater than or equal to 50%, greater than or equal to 60%, or even greater than or equal to 70%. In embodiments, the textured glass article 100 can have a transmittance haze less than or equal to 98%, less than or equal to 95%, or even less than or equal to 90%. In embodiments, the textured glass article 100 can have a transmittance haze greater than or equal to 50% and less than or equal to 98%, greater than or equal to 50% and less than or equal to 95%, greater than or equal to 50% and less than or equal to 90%, greater than or equal to 60% and less than or equal to 98%, greater than or equal to 60% and less than or equal to 95%, greater than or equal to 60% and less than or equal to 90%, greater than or equal to 70% and less than or equal to 98%, greater than or equal to 70% and less than or equal to 95%, or even greater than or equal to 70% and less than or equal to 90%, or any and all sub-ranges formed by any of these endpoints.

[0090] In embodiments, the relatively high transmittance of the textured glass article 100 allows for the placement of ink on the backside (i.e., opposite the textured side) of the textured glass article 100 to provide a different color or pattern or to include text (e.g., a company logo). In embodiments, the textured glass article 100 can have a transmittance greater than or equal to 70% or even greater than or equal to 80%. In embodiments, the textured glass article 100 can have a transmittance less than or equal to 99% or even less than or equal to 95%. In embodiments, the textured glass article 100 can have a transmittance greater than or equal to 70% and less than or equal to 99%, greater than or equal to 70% and less than or equal to 95%, greater than or equal to 80% and less than or equal to 99%, or even greater than or equal to 80% and less than or equal to 95%, or any and all sub-ranges formed by any of these endpoints.

[0091] In embodiments, each of the plurality of polyhedral surface features 106 can include a dendritic feature extending from the base 108 of the polyhedral surface feature 106. Individual dendritic features can not provide a high reflectivity. However, when formed in combination with the polyhedral surface features 106, a desired high reflective appearance can be achieved.

[0092] The structure of each polyhedral surface feature 106, including the flat converging facets 110 and the roughly straight along the relatively large base 108, reflects light in different directions to achieve a "glowing" (i.e., high-reflectance) appearance. The "glowing" appearance of the textured glass article can be evidenced by a relatively large 450 nm reflectance, peak GU, FWHM, GU value range, skewness, and kurtosis, as compared to a textured glass article lacking polyhedral surface features.

[0093] A relatively large 450 nm reflectance corresponds to more light being reflected from the flat converging facets 110 of the polyhedral surface features 106. In embodiments, the textured glass article 100 can have a 450 nm reflectance greater than or equal to 5% or even greater than or equal to 10%. In embodiments, the textured glass article 100 can have a 450 nm reflectance less than or equal to 30% or even less than or equal to 25%. In embodiments, the textured glass article can have a 450 nm reflectance greater than or equal to 5% and less than or equal to 30%, greater than or equal to 5% and less than or equal to 25%, greater than or equal to 10% and less than or equal to 30%, or even greater than or equal to 10% and less than or equal to 25%, or any and all sub-ranges formed by any of these endpoints.

[0094] The relatively high peak GU within the GU distribution corresponds to more light being reflected from the flat converging facets 110 of the polyhedral surface features 106. In embodiments, the textured glass article 100 can have a peak GU greater than or equal to 50 GU, greater than or equal to 60 GU, greater than or equal to 70 GU, or even greater than or equal to 80 GU. In embodiments, the textured glass article 100 can have a peak GU less than or equal to 150 GU, less than or equal to 125 GU, less than or equal to 115 GU, or even less than or equal to 100 GU. In embodiments, the textured glass article can have a peak GU greater than or equal to 50 GU and less than or equal to 150 GU, greater than or equal to 50 GU and less than or equal to 125 GU, greater than or equal to 50 GU and less than or equal to 115 GU, greater than or equal to 50 GU and less than or equal to 100 GU, greater than or equal to 60 GU and less than or equal to 150 GU, greater than or equal to 60 GU and less than or equal to 125 GU, greater than or equal to 60 GU and less than or equal to 115 GU, greater than or equal to 60 GU and less than or equal to 100 GU, greater than or equal to 70 GU and less than or equal to 150 GU, greater than or equal to 70 GU and less than or equal to 125 GU, greater than or equal to 70 GU and less than or equal to 115 GU, greater than or equal to 70 GU and less than or equal to 100 GU, greater than or equal to 80 GU and less than or equal to 150 GU, greater than or equal to 80 GU and less than or equal to 125 GU, greater than or equal to 80 GU and less than or equal to 115 GU, or even greater than or equal to 80 GU and less than or equal to 100 GU, or any and all sub-ranges formed by any of these endpoints.

[0095] The relatively large FWHM and GU value range corresponds to a broad distribution of gray scale values, which increases with surface feature size.

[0096] In embodiments, the textured glass article 100 can have a FWHM greater than or equal to 10 GU or even greater than or equal to 25 GU. In embodiments, the textured glass article 100 can have a FWHM less than or equal to 75 GU or even less than or equal to 60 GU. In embodiments, the textured glass article 100 can have a FWHM greater than or equal to 10 GU and less than or equal to 75 GU, greater than or equal to 10 GU and less than or equal to 60 GU, greater than or equal to 25 GU and less than or equal to 75 GU, or even greater than or equal to 25 GU and less than or equal to 60 GU, or any and all sub-ranges formed by any of these endpoints.

[0097] In embodiments, the textured glass article 100 can have a GU value range of greater than or equal to 100 GU or even greater than or equal to 125 GU. In embodiments, the textured glass article 100 can have a GU value range of less than or equal to 300 GU or even less than or equal to 250 GU. In embodiments, the textured glass article 100 can have a GU value range of greater than or equal to 100 GU and less than or equal to 300 GU, greater than or equal to 100 GU and less than or equal to 250 GU, greater than or equal to 125 GU and less than or equal to 300 GU, or even greater than or equal to 125 GU and less than or equal to 250 GU, or any and all sub-ranges formed by any of these endpoints.

[0098] Skew describes the asymmetry of the gray scale distribution. A relatively large skew corresponds to a large positive (“right-handed”) asymmetry with respect to the mean gray scale value, which indicates a greater amount of high intensity contribution (e.g., above the upper limit of the 75% interquartile range) to the distribution of light reflected from the flat converging facets 110 of the polyhedral surface features 106. In embodiments, the textured glass article can have a skew of greater than or equal to 0.05 or even greater than or equal to 0.1. In embodiments, the textured glass article 100 can have a skew of less than or equal to 0.7 or even less than or equal to 0.5. In embodiments, the textured glass article 100 can have a skew of greater than or equal to 0.05 and less than or equal to 0.7, greater than or equal to 0.05 and less than or equal to 0.5, greater than or equal to 0.1 and less than or equal to 0.7, or even greater than or equal to 0.1 and less than or equal to 0.5, or any and all sub-ranges formed by any of these endpoints.

[0099] Kurtosis provides a measure of outliers in the distribution of gray scale values. The more "heavy-tailed" the distribution, the more outliers exist. Since the kurtosis of an ideal normal distribution is three, using excess kurtosis (which is the kurtosis minus three) can more easily be compared to a normal distribution. By subtracting three, the kurtosis of an idealized normal distribution is thus shifted to zero, and any additional kurtosis in a sample distribution is referred to as excess kurtosis. A relatively large excess kurtosis indicates a large number of high-intensity gray scale value outliers (e.g., outside the upper limit of the 75% interquartile range) exist, corresponding to a more substantial high-intensity contribution to the distribution of light reflected from the flat converging facets 110 of the polyhedral surface features 106. In embodiments, the textured glass article 100 can have an excess kurtosis greater than or equal to 0.5 or even greater than or equal to 0.75. In embodiments, the textured glass article 100 can have an excess kurtosis less than or equal to 3 or even less than or equal to 2. In embodiments, the textured glass article 100 can have an excess kurtosis greater than or equal to 0.5 and less than or equal to 3, greater than or equal to 0.5 and less than or equal to 2, greater than or equal to 0.75 and less than or equal to 3, or even greater than or equal to 0.75 and less than or equal to 2, or any and all sub-ranges formed by any of these endpoints.

[0100] Dendritic surface features

[0101] Referring now to Figure 3 and Figure 4 In other embodiments, the textured glass article 200 described herein has a body 202 that includes an alumino-silicate glass that includes greater than or equal to 16 wt.% AI2O3and an AI2O3 / SiO2ratio of greater than 0.3. In embodiments, the alumino-silicate glass article can include: greater than or equal to 52 wt.% and less than or equal to 62 wt.% SiO2; greater than or equal to 16 wt.% and less than or equal to 28 wt.% AI2O3; greater than or equal to 0 wt.% and less than or equal to 5 wt.% B2O3; greater than or equal to 8 wt.% and less than or equal to 13 wt.% Na2O; greater than or equal to 0 wt.% and less than or equal to 0.2 wt.% K2O; greater than or equal to 0 wt.% and less than or equal to 4 wt.% Li2O; and greater than or equal to 0 wt.% and less than or equal to 1.5 wt.% MgO. However, it should be understood that other alumino-silicate glasses can also be considered and are possible so long as the alumino-silicate glass has greater than or equal to 16 wt.% AI2O3and an AI2O3 / SiO2ratio of greater than 0.3.

[0102] The body 202 includes at least a first surface 204. A plurality of dendritic surface features 206 extend from the first surface 204. Each dendritic surface feature 206 includes a base 208 on the first surface 204.

[0103] In embodiments, the surface feature size at the base 208 can be greater than or equal to 100 pm and less than or equal to 350 pm. In embodiments, the surface feature size at the base 208 can be greater than or equal to 100 pm, greater than or equal to 125 pm, or even greater than or equal to 150 pm. In embodiments, the surface feature size at the base 208 can be less than or equal to 350 pm, less than or equal to 250, or even less than or equal to 200 pm. In embodiments, the surface feature size at the base 208 can be greater than or equal to 100 pm and less than or equal to 350 pm, greater than or equal to 100 pm and less than or equal to 250 pm, greater than or equal to 100 pm and less than or equal to 200 pm, greater than or equal to 125 pm and less than or equal to 350 pm, greater than or equal to 125 pm and less than or equal to 250 pm, greater than or equal to 125 pm and less than or equal to 200 pm, greater than or equal to 150 pm and less than or equal to 350 pm, greater than or equal to 150 pm and less than or equal to 250 pm, or even greater than or equal to 150 pm and less than or equal to 200 pm, or any and all sub-ranges formed by any of these endpoints.

[0104] The structure of each dendritic surface feature 206 helps to achieve the desired enhanced tactile sensation.

[0105] In embodiments, the textured glass article 200 can have a surface roughness Ra that is greater than or equal to 2 pm. In embodiments, the textured glass article 200 can have a surface roughness Ra that is less than or equal to 4 pm or even less than or equal to 3 pm. In embodiments, the textured glass article 200 can have a surface roughness Ra that is greater than or equal to 2 pm and less than or equal to 4 pm, or even greater than or equal to 2 pm and less than or equal to 3 pm, or any and all sub-ranges formed by any of these endpoints.

[0106] The transmittance haze of the textured glass article 200 can be correlated to the surface roughness Ra, i.e., a relatively greater transmittance haze can mean that the textured glass article 200 has a relatively greater surface roughness Ra. In embodiments, the textured glass article 200 can have a transmittance haze greater than or equal to 50%, greater than or equal to 60%, or even greater than or equal to 70%. In embodiments, the textured glass article 200 can have a transmittance haze less than or equal to 98%, less than or equal to 95%, or even less than or equal to 90%. In embodiments, the textured glass article 200 can have a transmittance haze greater than or equal to 50% and less than or equal to 98%, greater than or equal to 50% and less than or equal to 95%, greater than or equal to 50% and less than or equal to 90%, greater than or equal to 60% and less than or equal to 98%, greater than or equal to 60% and less than or equal to 95%, greater than or equal to 60% and less than or equal to 90%, greater than or equal to 70% and less than or equal to 98%, greater than or equal to 70% and less than or equal to 95%, or even greater than or equal to 70% and less than or equal to 90%, or any and all sub-ranges formed by any of these endpoints.

[0107] The relatively high transmittance of the textured glass article 200 allows for the placement of ink on the backside (i.e., opposite the textured side) of the textured glass article 200 to provide a different color or pattern or to include text (e.g., a company logo). In embodiments, the textured glass article 200 can have a transmittance greater than or equal to 75% or even greater than or equal to 85%. In embodiments, the textured glass article 200 can have a transmittance less than or equal to 99% or even less than or equal to 97%. In embodiments, the textured glass article 200 can have a transmittance greater than or equal to 75% and less than or equal to 99%, greater than or equal to 75% and less than or equal to 97%, greater than or equal to 85% and less than or equal to 99%, or even greater than or equal to 85% and less than or equal to 97%, or any and all sub-ranges formed by any of these endpoints.

[0108] In embodiments, the textured glass article 200 can have a 450 nm reflectance greater than or equal to 1% or even greater than or equal to 5%. In embodiments, the textured glass article 100 can have a 450 nm reflectance less than or equal to 20% or even less than or equal to 15%. In embodiments, the textured glass article 200 can have a 450 nm reflectance greater than or equal to 1% and less than or equal to 20%, greater than or equal to 1% and less than or equal to 15%, greater than or equal to 5% and less than or equal to 20%, or even greater than or equal to 5% and less than or equal to 15%, or any and all sub-ranges formed by any of these endpoints.

[0109] In embodiments, each of the plurality of dendritic surface features 206 can include a polyhedral structure extending from a base 208 of the dendritic surface feature 206 and away from the first surface 204. The polyhedral surface features can not alone provide the enhanced tactile feel. However, when formed in combination with the dendritic surface features 206, the desired enhanced tactile feel can be achieved.

[0110] Methods of forming textured glass articles

[0111] Referring now to Figure 5 , a method of forming a textured glass article by a chemical etching process is shown at 300. At block 302 and as shown in Figure 6 , an aluminosilicate glass article 400 including greater than or equal to 16 wt% AI2O3 is initially provided. In embodiments where polyhedral surface features are desired to produce a high-reflectivity appearance, the aluminosilicate glass article 400 can be an aluminosilicate glass article including greater than or equal to 16 wt% AI2O3 and having an AI2O3 / SiO2 ratio of less than or equal to 0.3 (as described with reference to the aluminosilicate glass article 100 herein). In embodiments where dendritic surface features are desired to produce an enhanced tactile feel, the aluminosilicate glass article 400 can be an aluminosilicate glass article including greater than or equal to 16 wt% AI2O3 and having an AI2O3 / SiO2 ratio of greater than 0.3 (as described with reference to the aluminosilicate glass article 200 herein).

[0112] The aluminosilicate glass article 400 can be in the form of a sheet having a first surface and a second surface opposite and generally parallel to the first surface. In embodiments, the aluminosilicate glass article 400 can be pre-cleaned with a cleaning solution including potassium hydroxide, hydrofluoric acid, hydrochloric acid, or a combination thereof.

[0113] Referring back to Figure 5 , at block 304 and as shown in Figure 7 , the aluminosilicate glass article 400 is contacted with an etchant. The etchant reacts with the aluminosilicate glass article 400, which causes silicate and / or aluminate species to be released from the aluminosilicate glass article 400. The silicate and / or aluminate species combine with elements of the etchant to produce precipitates. If the solubility of these precipitates in the etchant is low, they can deposit on the surface of the aluminosilicate glass article 400 to form seeds 402 (e.g., salt crusts).

[0114] As Figure 8As shown, seed crystal 402 grows as the etchant continues to react with the aluminosilicate glass article 400. Because seed crystal 402 is insoluble in the etchant, it serves as an in-situ shield 404. Shield 404 seals a portion of the surface of the aluminosilicate glass article 400. Etching removes the glass surrounding shield 404 to create surface feature 406. The shape of surface feature 406 can be determined by the shape of shield 406, which can be varied by changing the composition of the etchant and / or changing the duration of etchant contact with the aluminosilicate glass article 400.

[0115] Please refer back to the previous page. Figure 5 In block 306 and as Figure 9 As shown, the aluminosilicate glass article 400 is cleaned to remove etchant and seed crystals 402 from its surface, and then dried to form a textured glass article 410 having surface features 406. In one embodiment, the etchant is washed away from the aluminosilicate glass article 400 with deionized (DI) water. In another embodiment, the seed crystals 402 adhering to the aluminosilicate glass article 400 can be removed by, for example, a scrubbing sponge. Please refer back to [link to previous document]. Figure 6 In block 308, in this embodiment, the aluminosilicate glass article 400 is dried under ambient conditions. Alternatively, the aluminosilicate glass article 400 may be heated to dry the glass article.

[0116] although Figure 8 and Figure 9 The surface feature 406 shown is a polyhedral surface feature, but it should be understood that the method described herein can be similarly used to generate dendritic surface features.

[0117] To produce polyhedral surface features, aluminosilicate glass articles containing ≥16% by weight of Al₂O₃ may have an Al₂O₃ / SiO₂ ratio ≤0.3, such that etchants with a pH ≤3, as described herein, preferentially produce silicon-based precipitates and minimize aluminum-based precipitates. Silicon-based precipitates (e.g., metal fluorosilicates (MSiF₆)) result in polyhedral surface features, which can lead to a highly reflective appearance.

[0118] To produce dendritic surface features, aluminosilicate glass articles containing 16% or more Al₂O₃ by weight can have an Al₂O₃ / SiO₂ ratio greater than 0.3, such that etchants with a pH less than 3, as described herein, preferentially produce aluminum-based precipitates and minimize silicon-based precipitates. Aluminum-based precipitates (e.g., metallic fluoroaluminate (MAlF₅)) result in small dendritic surface features, which can lead to an improved tactile feel.

[0119] Accordingly, in embodiments, the etching agents described herein have a pH less than or equal to 3.0. In embodiments, the etching agents can have a pH: less than or equal to 3.0, less than or equal to 2.8, or even less than or equal to 2.6.

[0120] In embodiments, as described in further detail herein, the etching agents can include a salt and an acid.

[0121] The salt present in the etching agent can act as a crystallization promoter that facilitates the formation of seed crystals. In embodiments, the salt can include: ammonium chloride, ammonium fluoride, ammonium bifluoride, ammonium sulfate, ammonium nitrate, potassium sulfate, potassium chloride, potassium fluoride, potassium bifluoride, potassium nitrate, sodium chloride, sodium fluoride, sodium bifluoride, or combinations thereof. The amount of salt in the etching agent should be high enough (e.g., greater than or equal to 20 wt.%) to ensure the formation of seed crystals. The amount of salt can be limited (e.g., less than or equal to 40 wt.%) to reduce or prevent undissolved salt that can precipitate upon reaching solubility. Undissolved salt can etch differently from the etching agent and can result in a lack of uniformity across the textured glass surface. In embodiments, the etching agent can include greater than or equal to 20 wt.% and less than or equal to 40 wt.% of a salt. In embodiments, the amount of salt in the etching agent can be greater than or equal to 20 wt.%, greater than or equal to 24 wt.%, or even greater than or equal to 28 wt.%. In embodiments, the amount of salt in the etching agent can be less than or equal to 40 wt.%, less than or equal to 36 wt.%, or even less than or equal to 32 wt.%. In embodiments, the amount of salt in the etching agent can be: greater than or equal to 20 wt.% and less than or equal to 40 wt.%, greater than or equal to 20 wt.% and less than or equal to 36 wt.%, greater than or equal to 20 wt.% and less than or equal to 32 wt.%, greater than or equal to 24 wt.% and less than or equal to 40 wt.%, greater than or equal to 24 wt.% and less than or equal to 36 wt.%, greater than or equal to 24 wt.% and less than or equal to 32 wt.%, greater than or equal to 28 wt.% and less than or equal to 40 wt.%, greater than or equal to 28 wt.% and less than or equal to 36 wt.%, or even greater than or equal to 28 wt.% and less than or equal to 32 wt.%, or any and all sub-ranges formed by any of these endpoints.

[0122] The acid present in the etchant functions to dissolve the glass network of the aluminum silicate glass article and form the surface features. In embodiments, the acid can include hydrochloric acid, hydrofluoric acid, nitric acid, sulfuric acid, oxalic acid, acetic acid, a bisulfate salt (e.g., sodium bisulfate), or combinations thereof. The amount of acid in the etchant should be high enough (e.g., greater than or equal to 30 wt.%) to ensure etching of the glass and formation of the textured glass article. The amount of acid can be limited (e.g., less than or equal to 65 wt.%) to ensure the surface features are produced. When too much acid is added, the surface features can be etched to a smaller size, lose their high reflective appearance, and / or increase in tactile feel. In embodiments, the etchant can include greater than or equal to 30 wt.% and less than or equal to 65 wt.% acid. In embodiments, the amount of acid in the etchant can be greater than or equal to 30 wt.%, greater than or equal to 35 wt.%, or even greater than or equal to 40 wt.%. In embodiments, the amount of acid in the etchant can be less than or equal to 65 wt.%, less than or equal to 55 wt.%, or even less than or equal to 45 wt.%. In embodiments, the amount of acid in the etchant can be: greater than or equal to 30 wt.% and less than or equal to 65 wt.%, greater than or equal to 30 wt.% and less than or equal to 55 wt.%, greater than or equal to 30 wt.% and less than or equal to 45 wt.%, greater than or equal to 35 wt.% and less than or equal to 65 wt.%, greater than or equal to 35 wt.% and less than or equal to 55 wt.%, greater than or equal to 35 wt.% and less than or equal to 45 wt.%, greater than or equal to 40 wt.% and less than or equal to 65 wt.%, greater than or equal to 40 wt.% and less than or equal to 55 wt.%, or even greater than or equal to 40 wt.% and less than or equal to 45 wt.%, or any and all sub-ranges formed by any of these endpoints.

[0123] In embodiments, the etchant can further include a solvent. In embodiments, the solvent can include water, an acid (e.g., hydrochloric acid and / or hydrofluoric acid), or combinations thereof. In embodiments, the etchant can include greater than or equal to 20 wt.% and less than or equal to 40 wt.% solvent. In embodiments, the amount of solvent in the etchant can be greater than or equal to 20 wt.% or even greater than or equal to 25 wt.%. In embodiments, the amount of solvent in the etchant can be less than or equal to 40 wt.% or even less than or equal to 35 wt.%. In embodiments, the amount of solvent in the etchant can be: greater than or equal to 20 wt.% and less than or equal to 40 wt.%, greater than or equal to 20 wt.% and less than or equal to 35 wt.%, greater than or equal to 25 wt.% and less than or equal to 40 wt.%, or even greater than or equal to 25 wt.% and less than or equal to 35 wt.%, or any and all sub-ranges formed by any of these endpoints.

[0124] In embodiments, the etchant is prepared by mixing the components and stirring for at least 12 hours (i.e., aging). After stirring, the supernatant is decanted and used as the etchant.

[0125] In embodiments, the etchant can comprise: greater than or equal to 20 wt.% and less than or equal to 40 wt.% ammonium fluoride; greater than or equal to 25 wt.% and less than or equal to 45 wt.% nitric acid; greater than or equal to 5 wt.% and less than or equal to 20 wt.% hydrofluoric acid; and greater than or equal to 20 wt.% and less than or equal to 40 wt.% water.

[0126] The textured glass articles described herein can be used in a variety of applications, including, for example, back cover applications in consumer or commercial electronic devices such as smart phones, tablet computers, personal computers, ultra-thin notebooks, televisions, and cameras. Figures 10-12 Example articles incorporating any of the textured glass articles disclosed herein are shown. In particular, Figures 10-12 A consumer electronic device 500 is illustrated, including a housing 502 having a front surface 504, a back surface 506, and side surfaces 508; electrical components (not shown) located at least partially within the housing or entirely within the housing and including at least a controller, memory, and a display 510 at or near the front surface of the housing; and a cover substrate 512 over the display at or over the front surface of the housing. In embodiments, a portion of the housing 502, such as the back surface 506, can include any of the textured glass articles disclosed herein.

[0127] Embodiments

[0128] To more readily understand various embodiments, reference is made to the following examples, which illustrate various embodiments of the textured glass articles described herein.

[0129] Glass articles having glass compositions 1 and 2 shown in Table 1 were treated as described below.

[0130] The compositions of glass articles 1 and 2 treated in the methods described below are listed in Table 1. Note that references to "glass article 1" and "glass article 2" refer to glass articles having the respective compositions listed in Table 1. References to glass articles 1 and 2 do not refer to the same glass articles 1 and 2, respectively, treated multiple times with various etchants.

[0131] Table 1

[0132]

[0133] Table 2 lists the composition of ammonium salt example etchant 1. Table 3 lists the respective treatment times and respective properties of the resulting textured glass articles. Control textured glass articles CG A and CG B were formed from glass articles 1 and 2, respectively. The example textured glass articles EG were formed by treating glass articles 1 and 2 with example etchant 1.A to EG E The glass articles were 50 mm x 50 mm x 1.1 mm squares. Prior to treatment with the respective ammonium etchant, the glass articles were pre-cleaned with 4 wt% SemiClean KG detergent [produced by Yokohama Oils and Fats Industry Co., Ltd.] at 60 °C with sonication for 2 minutes, rinsed with DI water, and dried in a desiccator. Except for the glass articles used to form the example textured glass articles EG B The glass articles were pre-etched with 10 vol% HF / 20 vol% HC1 at 22 °C for 2 minutes, rinsed with DI water, shaken to remove excess water, and transferred to the respective etchant. The glass articles were treated with the respective etchant by vertically submerging and holding the glass articles in the etchant for the times indicated in Table 3. The glass articles were then removed from the etchant, rinsed with DI water, and dried at 110 °C.

[0134] Table 2

[0135]

[0136] Table 3

[0137]

[0138]

[0139] Table 3 continued

[0140]

[0141] Etchant 1 was prepared by mixing 33 wt% nitric acid, 10 wt% hydrofluoric acid, 30 wt% ammonium fluoride, and 27 wt% water. After stirring for 12 hours, the supernatant was poured into polyethylene vials used to treat glass articles 1 and 2.

[0142] Glass article 2 was treated with example etchant 1 for 2, 4, and 8 minutes, resulting in example textured glass articles EG A , EG B , and EG C , respectively, the surfaces of which are shown in Figures 13-15 As shown, the example textured glass articles EG A , EG B , and EG C have a polyhedral crystal structure. See now Figure 16 , example textured glass article EG AXRD spectra of the resulting etchant precipitates include peaks indicative of the presence of metal fluosilicate-type precipitates (i.e., deposits containing SiF6such as ammonium fluosilicate) and do not include any peaks indicative of the presence of fluoroaluminate precipitates (i.e., deposits containing Al). Thus, the example textured glass articles EG A , EG B , and EG C have resulting etchant precipitates that include metal fluosilicate-type precipitates and do not include any aluminate-type precipitates. While not wishing to be bound by theory, only the metal fluosilicate-type precipitates precipitate out, resulting in large polyhedral structures.

[0143] The resulting surface features of the example textured glass articles EG A , EG B , and EG C have surface feature sizes of 87 ± 20 μιη, 90 ± 17 μιη, and 81 ± 16 μιη, respectively. The example textured glass article EG A has a transmission haze of 82.9 ± 0.3%, a surface roughness of 1.6 ± 0.3 μιη, a transmission of 91.9 ± 0.02%, and a 450 nm reflectance of 15.2 ± 0.4%. The example textured glass article EG B has a transmission haze of 96.2 ± 0.5%, a surface roughness of 1.6 ± 0.2 μιη, a transmission of 89.98 ± 0.09%, and a 450 nm reflectance of 18.4 ± 0.2%. The example textured glass article EG C has a transmission haze of 89.04 ± 0.02%, a surface roughness of 1.9 ± 0.2 μιη, a transmission of 90.66 ± 0.07%, and a 450 nm reflectance of 20.4 ± 0.7%.

[0144] Treating the glass article 1 with the example etchant 1 for 4 minutes resulted in the example textured glass articles EG D and EG E , respectively, the surfaces of which are shown in Figure 17 and Figure 18 , respectively. As shown, the example textured glass articles EG D and EG E have dendritic crystal structures. See now Figure 19 , the XRD spectrum of the example textured glass article EG D includes peaks indicative of the presence of metal fluoroaluminate-type precipitates (i.e., deposits containing Al such as ammonium hexafluoroaluminate) and does not include any peaks indicative of the presence of fluosilicate-type precipitates (i.e., deposits containing SiF6). Thus, the example textured glass articles EG D and EG EThe resulting etchant precipitates of the Example textured glass articles EG include metal fluoroaluminate-type precipitates and do not include any fluoro-silicate-type precipitates. While not wishing to be bound by theory, only the metal fluoroaluminate-type precipitates precipitating out results in the dendritic structures.

[0145] Example textured glass article EG D having a transmission haze of 85.7 ± 0.9%, a surface roughness of 2.2 ± 0.5 μιη, a transmission of 86.74 ± 0.03%, and a 450 nm reflectance of 7.91 ± 0.01%. Example textured glass article EG E having a transmission haze of 83.77 ± 0.04%, a surface roughness of 2.2 ± 0.3 μιη, a transmission of 95.61 ± 0.02%, and a 450 nm reflectance of 8.13 ± 0.02%.

[0146] As Figures 12-19 As

[0147] Table 4 lists the corresponding gray scale distribution properties of the Example textured glass articles EG A , EG B , and EG C .

[0148] Table 4

[0149]

[0150]

[0151] The relatively higher peak GU values of the Example textured glass articles EG A , EG B , and EG C indicate that more light is reflected from the surface of the Example textured glass articles compared to the control textured glass articles.

[0152] The relatively higher FWHM and GU value ranges of the Example textured glass articles EG A , EG B , and EG C indicate that the polyhedral surface features of the Example textured glass articles result in a relatively broad distribution of gray scale values.

[0153] The textured glass article EG of the example A , EG B , and EG C The "tail" of the distribution to the right is longer, and thus contributes a greater amount of high intensity light to the light distribution than the control textured glass article.

[0154] The textured glass article EG of the example A , EG B , and EG C The excess kurtosis level of the example textured glass article indicates that there is a significant amount of gray value outliers in the polyhedral surface structure of the example textured glass article.

[0155] Referring back to Table 3, the example textured glass article textured glass article EG A , EG A , EG B , and EG C has a greater 450 nm reflectance, and thus reflects more light from the surface of the glass article. While not wishing to be bound by theory, reflecting more light from the surface of the glass article results in a "glittery" (i.e., high reflectivity) appearance.

[0156] As exemplified in Table 4, treating an aluminosilicate glass article containing greater than or equal to 16 wt% AI2O3 and a ratio of AI2O3 / SiO2 less than or equal to 0.3 results in the formation of polyhedral surface features that achieve a "glittery" (i.e., high reflectivity) appearance as evidenced by relatively large peak GU, FWHM, GU value range, skew, excess kurtosis, and 450 nm reflectance.

[0157] Those of skill in the art will understand that various modifications and changes can be made to the embodiments described herein without departing from the spirit and scope of the claimed subject matter. Accordingly, it is intended that this description be construed as encompassing various embodiments and variations of the described embodiments, falling within the scope of the appended claims and their equivalents.

Claims

1. A textured glass article, comprising: a body comprising an alumino-silicate glass comprising greater than or equal to 16 percent by weight A1203 and a ratio of A1203 / Si02 less than or equal to 0.3, the body having at least a first surface; a plurality of polyhedral surface features extending from the first surface, each polyhedral surface feature of the plurality of polyhedral surface features comprising a base on the first surface, a plurality of facets extending from the first surface, and a surface feature size at the base greater than or equal to 10 pm and less than or equal to 100 pm, wherein the plurality of facets of each polyhedral surface feature converge toward one another; and a transmission haze greater than or equal to 50 percent.

2. The textured glass article of claim 1, wherein the plurality of facets of each polyhedral surface feature converge toward one another to form at least one apex that is sharp, rounded, or truncated.

3. The textured glass article of claim 1, wherein the textured glass article has a surface roughness Ra greater than or equal to 1 pm.

4. The textured glass article of claim 1, wherein the base of each polyhedral surface feature of the plurality of polyhedral surface features comprises at least three edges, at least one edge converging toward at least another edge.

5. The textured glass article of claim 1, wherein each polyhedral surface feature of the plurality of polyhedral surface features comprises a dendritic structure extending from the base.

6. The textured glass article of any one of claims 1 to 5, wherein the textured glass article has a peak maximum greater than or equal to 50 GU and less than or equal to 150 GU, wherein GU is a gray scale unit of an image collected from reflected light off a surface of the article.

7. The textured glass article of any one of claims 1 to 5, wherein the textured glass article has a full width at half maximum greater than or equal to 10 GU and less than or equal to 70 GU, wherein GU is a gray scale unit of an image collected from reflected light off a surface of the article.

8. The textured glass article of any one of claims 1 to 5, wherein the textured glass article has a GU value range greater than or equal to 100 GU and less than or equal to 300 GU, wherein GU is a gray scale unit of an image collected from reflected light off a surface of the article.

9. The textured glass article of any one of claims 1 to 5, wherein the textured glass article has a skew greater than or equal to 0.05 and less than or equal to 0.

7.

10. The textured glass article of any one of claims 1 to 5, wherein the textured glass article has a kurtosis greater than or equal to 0.5 and less than or equal to 3.

11. The textured glass article of any one of claims 1 to 5, wherein the textured glass article comprises: Si02 greater than or equal to 52 percent by weight and less than or equal to 67 percent by weight; A1203 greater than or equal to 16 percent by weight and less than or equal to 28 percent by weight; greater than or equal to 0 weight percent and less than or equal to 5 weight percent B203; greater than or equal to 8 weight percent and less than or equal to 15 weight percent Na20; greater than or equal to 0 weight percent and less than or equal to 0.2 weight percent K20; greater than or equal to 0 weight percent and less than or equal to 4 weight percent Li20; and greater than or equal to 0 weight percent and less than or equal to 5 weight percent MgO.

12. The textured glass article of any of claims 1 to 5, wherein the textured glass article is an electronic device back cover.

13. A textured glass article, comprising: a body comprising an aluminosilicate glass comprising greater than or equal to 16 weight percent Al203and an Al203 / Si02ratio of greater than 0.3, the body having at least a first surface; a plurality of dendritic surface features extending from the first surface, each of the plurality of dendritic surface features comprising a base on the first surface, and a surface feature size at the base of greater than 100 pm and less than or equal to 350 pm; and a transmittance haze of greater than or equal to 50 percent.

14. The textured glass article of claim 13, wherein the textured glass article has a surface roughness Ra of greater than or equal to 2 pm.

15. The textured glass article of claim 13 or claim 14, wherein the aluminosilicate glass comprises: greater than or equal to 52 weight percent and less than or equal to 62 weight percent Si02; greater than or equal to 16 weight percent and less than or equal to 28 weight percent Al203; greater than or equal to 0 weight percent and less than or equal to 5 weight percent B203; greater than or equal to 8 weight percent and less than or equal to 13 weight percent Na20; greater than or equal to 0 weight percent and less than or equal to 0.2 weight percent K20; greater than or equal to 0 weight percent and less than or equal to 4 weight percent Li20; and greater than or equal to 0 weight percent and less than or equal to 1.5 weight percent MgO.

16. The textured glass article of any of claims 13 to 14, wherein the textured glass article is an electronic device back cover.

17. A method of forming a textured glass article, the method comprising the steps of: contacting an aluminosilicate glass article with an etchant, wherein the aluminosilicate glass article comprises greater than or equal to 16 weight percent Al203and has at least one surface, and the etchant comprises a pH of less than or equal to 3.0; rinsing the aluminosilicate glass article; and drying the aluminosilicate glass article to form the textured glass article, the textured glass article comprising a plurality of surface features extending from a first surface of the textured glass article, each of the plurality of surface features comprising a base on the first surface, wherein a surface feature size at the base is greater than or equal to 10 pm and less than or equal to 100 pm, wherein the textured glass article has a transmittance haze of greater than or equal to 50 percent, wherein the aluminosilicate glass article comprises an Al2O3 / SiO2 ratio less than or equal to 0.3, and wherein the plurality of surface features are polyhedral surface features.

18. The method of claim 17, wherein contacting the aluminosilicate glass article with the etchant produces more silicon-based precipitates than aluminum-based precipitates.

19. The method of any one of claims 17 to 18, wherein the etchant comprises: greater than or equal to 20 wt% and less than or equal to 40 wt% salt; and greater than or equal to 30 wt% and less than or equal to 65 wt% acid.

20. The method of any one of claims 17 to 18, wherein the etchant comprises: greater than or equal to 20 wt% and less than or equal to 40 wt% ammonium fluoride; greater than or equal to 25 wt% and less than or equal to 45 wt% nitric acid; greater than or equal to 5 wt% and less than or equal to 20 wt% hydrofluoric acid; and greater than or equal to 20 wt% and less than or equal to 40 wt% water.

21. A method of forming a textured glass article, the method comprising the steps of: contacting an aluminosilicate glass article with an etchant, wherein the aluminosilicate glass article comprises greater than or equal to 16 wt% Al2O3 and has at least one surface, and the etchant comprises a pH less than or equal to 3.0; rinsing the aluminosilicate glass article; and drying the aluminosilicate glass article to form the textured glass article, the textured glass article comprising a plurality of surface features extending from a first surface of the textured glass article, each surface feature of the plurality of surface features comprising a base portion on the first surface, wherein a surface feature dimension at the base portion is greater than or equal to 100 pm and less than or equal to 350 pm, and wherein the textured glass article has a transmittance haze greater than or equal to 50%, wherein the aluminosilicate glass article comprises an Al2O3 / SiO2 ratio greater than 0.3, and wherein the plurality of surface features are dendritic surface features.

22. The method of claim 21, wherein contacting the aluminosilicate glass article with the etchant produces more aluminum-based precipitates than silicon-based precipitates.

23. The method of any one of claims 21 to 22, wherein the etchant comprises: greater than or equal to 20 wt% and less than or equal to 40 wt% salt; and greater than or equal to 30 wt% and less than or equal to 65 wt% acid.

24. The method of any one of claims 21 to 22, wherein the etchant comprises: greater than or equal to 20 wt% and less than or equal to 40 wt% ammonium fluoride; greater than or equal to 25 wt% and less than or equal to 45 wt% nitric acid; greater than or equal to 5 wt% and less than or equal to 20 wt% hydrofluoric acid; and greater than or equal to 20 wt% and less than or equal to 40 wt% water.

25. A consumer electronic device, comprising: a housing having a front surface, a back surface, and side surfaces; and an electrical component at least partially located within the housing, the electrical component comprising at least a controller, a memory, and a display; ​ ​ wherein a back surface of the housing comprises the textured glass article of any of claims 1-16.

26. The consumer electronic device of claim 25, wherein the display is disposed at a front surface of the housing.

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