WO2023064097A1

WO2023064097A1 - Textured glass articles and methods of making the same

Info

Publication number: WO2023064097A1
Application number: PCT/US2022/044836
Authority: WO
Inventors: Kenneth Edward Hrdina; Yuhui Jin; Aize LI; Qiao Li; Wei Sun; Ying Wei
Original assignee: Corning Incorporated
Priority date: 2021-10-14
Filing date: 2022-09-27
Publication date: 2023-04-20
Also published as: TW202334053A

Abstract

A method of making a glass article includes providing a glass substrate including a thickness and a primary surface and treating a molten etchant bath by supplying humidified air with a controlled humidity level between 10% and 100% into the molten etchant bath for a predetermined time, thereby providing a treated etchant bath. The method further includes adding lithium salt to the treated etchant bath providing the treated etchant bath that includes (by weight): (a) 20% to about 90% nitrate salt, (b) 0.1% to 10% silicic acid, and (c) 0.1% to 25% lithium salt. The method further includes submerging the glass substrate in the treated molten etchant bath for an etching duration, wherein the submerging forms a haze over the primary surface of the glass substrate.

Description

TEXTURED GLASS ARTICLES AND METHODS OF MAKING THE SAME

PRIORITY

[0001] This Application claims the benefit of priority under 35 U.S.C. § 120 of U.S. Application No. 63/255,741 filed on October 14, 2021, the content of which is relied upon and incorporated hereby by reference in its entirety.

FIELD

[0002] The present disclosure generally relates to textured glass articles and methods of making the same, particularly textured glass articles with low sparkle characteristics and ionexchange etching methods of making the same.

BACKGROUND

[0003] Antiglare surfaces are often used in display devices such as LCD screens, tablets, smartphones, OLEDs and touch screens to avoid or reduce specular reflection of ambient light. In many display devices, these antiglare surfaces are formed by providing a level of roughness to one or more surfaces of the glass to spread and scatter incident light. Antiglare surfaces in the form of a roughened glass surface are often used on the front surfaces of these display devices to reduce the apparent visibility of external reflections from the display and improve readability of the display under differing lighting conditions.

[0004] Display “sparkle” or “dazzle” is a phenomenon that can occur when antiglare or light scattering surfaces are incorporated into a display system. Sparkle is the expression of a non-uniform pixel light intensity distribution. Further, sparkle is associated with a very fine grainy appearance that can appear to have a shift in the pattern of the grains with changing viewing angles of the display. This type of sparkle is observed when pixelated displays, such as LCDs, are viewed through an antiglare surface. As the resolution of display devices continues to increase, particularly for handheld electronic devices, the pixel pitch of the array of pixels employed in these devices continues to decrease, exacerbating unwanted sparkle effects.

[0005] Conventional approaches to making textured glass surfaces have been successful at producing some surfaces with good antiglare properties. However, some of these processes can include multiple processing steps that utilize harsh chemicals to produce texture with the desired durability or strength. In view of these considerations, there is a need for textured glass articles including surfaces with low sparkle characteristics that can be developed via efficiently while limiting environmental risks associated with harsh chemicals, such as hydrogen fluoride.

SUMMARY

[0006] According to an aspect of the disclosure, a method of making a glass article is disclosed. The method includes providing a glass substrate comprising a thickness and a primary surface and treating a molten etchant bath by supplying humidified air with a controlled humidity level between 10% and 100% into the molten etchant bath for a predetermined time, thereby providing a treated etchant bath. The method further includes adding lithium salt to the treated etchant bath providing the treated etchant bath that includes (by weight): (a) 20% to about 90% nitrate salt, (b) 0.1% to 10% silicic acid, and (c) 0.1% to 25% lithium salt. The method further includes submerging the glass substrate in the treated molten etchant bath for an etching duration, wherein the submerging forms a haze over the primary surface of the glass substrate.

[0007] According to another aspect of the disclosure, a display system is provided that includes the glass substrate having at least one roughened surface prepared by the aforementioned method. The glass substrate includes a haze of less than about 25; and a surface roughness (Ra) of about 5 nm to about 500 nm.

[0008] According to yet another aspect of the disclosure, a glass article is disclosed that includes at least one anti-glare surface prepared by the aforementioned method having a haze of less than about 25 and a transmittance greater than 90%. The anti-glare surface further includes a Distinctness-of-Image (DOI) 20° of about 80 to about 99.8 and a surface roughness (Ra) of about 5 nm to about 500 nm.

[0009] Additional features and advantages will be set forth in the detailed description which follows, and 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.

[0010] 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 disclosure as it is claimed.

[0011] The accompanying drawings are included to provide a further understanding of principles of the disclosure and are incorporated in, and constitute a part of, this specification. The drawings illustrate one or more embodiments) and, together with the description, serve to explain, by way of example, principles and operation of the disclosure. It is to be understood that various features of the disclosure disclosed in this specification and in the drawings can be used in any and all combinations. By way of non-limiting examples, the various features of the disclosure may be combined with one another according to the following aspects.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] These and other features, aspects and advantages of the present disclosure are better understood when the following detailed description of the disclosure is read with reference to the accompanying drawings, in which:

[0013] FIG. 1 is a perspective view of the exemplary electronic device;

[0014] FIG. 2 is a cross-sectional, schematic view of a chemically-strengthened, textured glass article;

[0015] FIG. 3 is a process diagram of a method of making a textured glass article;

[0016] FIG. 4A is a photograph of a glass article treated in a molten salt bath without a lithium salt;

[0017] FIG. 4B is a photograph of a glass article treated in a molten salt bath with 0.5% lithium salt;

[0018] FIG. 4C is a photograph of a glass article treated in a molten salt bath with 1% lithium salt;

[0019] FIG. 5A is a photograph of two glass articles chemically strengthened without silicic acid and with silicic acid;

[0020] FIG. 5B is a photograph of two glass articles chemically strengthened without silicic acid and with silicic acid;

[0021] FIG. 6 is a photograph of two glass articles chemically strengthened in molten salt baths that are unconditioned and conditioned demonstrating a comparative haze generation;

[0022] FIG. 7 is a chart demonstrating haze results measured for chemically-strengthened glass articles with variations in conditioning processes of molten salt baths in accordance with the disclosure; and

[0023] FIG. 8 is a graph showing haze formation on sample substrates according to one or more embodiments of this disclosure. DETAILED DESCRIPTION

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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. [0029] Referring to FIGS. 1 and 2, the disclosure generally provides for methods and procedures for preparing textured glass article 10 that provides beneficial glare-resistant properties that may be particularly beneficial for implementation in an electronic device 12. For example, as demonstrated in FIG. 1, the textured glass article 10 may provide a display surface 14 or user interface surface of the electronic device 12. The electronic device 12 may correspond to various devices that include a display 16 (e.g., light emitting diode [LED] displays, organic LED [OLED] displays, etc.) configured to visible information in the form of light transmitted through a thickness T of the article 10. Accordingly, the operation of the electronic device 12 and the corresponding user experience may be improved by limiting glare reflected from a primary surface 18a, 18b. Additionally, the longevity and operation of the electronic device 12 may benefit from improved strength and durability of the article 10. Though discussed in reference to the electronic device 12, the glass article may be applied in any application that may benefit from the characteristics of scratch-resistance, abrasion resistance, and glare mitigation.

[0030] As discussed herein, the electronic device 12 may correspond to various types of devices (e.g., consumer electronics, including mobile phones, tablets, computers, navigation systems, and the like), architectural articles, transportation articles (e.g., automotive, trains, aircraft, sea craft, etc.), appliance articles, or any article that requires some transparency, scratch-resistance, abrasion resistance, or a combination thereof. As depicted in FIG. 1, the electronic device 12 includes a housing 20 having front surface 20a, back surface 20b, and side surfaces 20c. Electrical components may be enclosed within the housing 20 and may include a controller, a memory, and the display 16 as well as various communication modules, peripherals, and related circuits. A cover substrate 22 is shown covering the front surface 20a of the housing 20 and may include the glass article 10 as provided by the disclosure. Additionally, in some embodiments, the glass article 10 may be incorporated or form any of the surface 20a, 20b, 20c of the electronic device 12.

[0031] Referring now to FIG. 2, an exemplary cross section of the glass article 10 is depicted as a glass substrate 30 with a first primary surface 18a and a second primary surface 18b, generally referred to as the primary surfaces 18 or the primary surface. Each of the primary surfaces 18 may form a textured surface 32, which may be substantially planar and include surface features 34 that provide for the anti-glare properties. The surface features 34 may generally correspond to surface hillocks 36 formed over at least one of primary surfaces 18. Each of the hillocks 36 includes a top surface 36a and a base 36b. The base 36b may be formed below the primary surface 18 of the substrate 30. Though discussed in reference to the hillocks 36 for clarity, the surface features may generally correspond to variations in height of the top surface 36a relative to the base 36b of each of the surface features 34, which may be in the form of angular facets, undulations, pits, crevices, or other variations associated with the processing techniques and methods provided by the disclosure. Accordingly, the methods and processing techniques provided by the disclosure provide for improved substrates 30 and glass articles 10 that provide for dispersion of ambient light that impinges on the primary surface 18.

[0032] As shown, the base 36b of the hillocks 36 may define a trough or bowl-shaped feature relative to the top surface 36a. The top surface 36a of each of the hillocks 36 may be located above, below, or substantially planar with the primary surface 18 of the substrate 30, which may be dependent on the processing technique applied to process the glass article 10 and/or the combined processes applied to provide the desired properties. In various implementations, each of the hillocks 36 may form a mesa-like appearance with the base 36b forming a substantially round shape and the top surface 36a being substantially planar. In some examples the hillocks 36 may be irregular in shape with angular variations or curvatures present among walls 42 of the hillocks 36. Further, in some implementations, the hillocks 36 may be characterized by pyramidal or mound-like cross-sectional shapes, with a base 36b that is square in shape and a top surface 36a that defines a sharp or rounded peak or tip feature.

[0033] Though the exact dimension of each of the surface features 34 may vary over the primary surface 18, the properties of the textured surface 32 may be defined as the average surface distances (e.g. lengths and heights) of the shapes forming the surface features 34. Accordingly, the textured surface 32 may be defined or measured by an average lateral feature size 44 and an average feature height 46. According to some embodiments of the glass article 10, the average lateral feature size 44 may be larger than the average feature height 46. In some implementations, a ratio between the average lateral feature size 44 and the average feature height 46 may be defined by a factor of 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 6, 7, 8, 9, 10, 15, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1500, 2000, 2500, 3000, 3500, 4000, 4500, 5000, 5500, 6000, 6500, 7000, 7500, 8000, 8500, 9000, 9500, 10000 and all factors between these values.

[0034] As further discussed in reference to FIGS. 3-7, the textured surface 32 of the glass substrate 30 may be effectuated by exposing the glass article 10 to a thermochemical treatment process. In some cases, the process may correspond to an exposure to a molten salt bath without requiring separate steps for etching and chemical strengthening. Additionally, the combined treatment can be achieved without the use of hydrofluoric acid, which is known to present a variety of hazards and related manufacturing costs. In general, the disclosure provides for an improved procedure that both etches and chemically strengthens the glass article 10 to provide the consistent levels of haze and strength that may otherwise require multiple processing steps, which may each require specialized equipment and training for operation. Accordingly, the disclosure provides for significant improvements to prepare the textured glass article 10 with equivalent or superior performance while achieving such performance in a single treatment step that does not required acid etching with harsh chemicals (e.g., hydrofluoric acid). An example of such a process a process is discussed in detail in reference to the exemplary method shown in FIG. 3 and later discussed in detail.

[0035] The steps outlined in FIGS. 3-7 generally provide for procedures and examples for effectuating the textured surface 32 while concurrently providing chemical strengthening via a temperature controlled exposure to a molten salt bath. As later discussed in further detail, chemical strengthening operates to produce a compressive stress region 50 extending from the primary surface 18 to a depth D. The compressive stress region 50 results from exposure the glass substrate 30 in the molten salt bath to large metal ions that replace smaller metal ions in an ion exchange process. The compressive stress region 50 extends from the primary surface 18 to the depth D and is balanced by a tensile stress region 52 (also referred to as “central tension”) within the interior of the glass substrate 30. lire depth of the compressive stress region is referred to as the “depth of layer” indicating the depth D to which the substrate is under compressive stress.

[0036] Still referring to FIG. 2, further specific details of the surface features 34 resulting from the methods and procedures of the disclosure are discussed in detail. The proportions of the shapes forming the textured surface 32 may reduce the level of sparkle or glare associated with the article 10 when exposed to ambient light. Each of the average lateral feature size 44 and average height 46 of the plurality of hillocks 36 is given by an average of the lateral feature sizes and heights of a sampling of the hillocks 36 within the textured surface 32, as measured according to analytical and statistical sampling techniques understood by those with ordinary skill in the field of this disclosure. With regard to analytical techniques, those with ordinary skill in the field of the disclosure may employ one or more analytical instruments to measure the average lateral feature size 44 and the average height 46, e.g., an atomic force microscope (AFM) for particularly small features (e.g., < 10 μm). With regard to statistical techniques, one with ordinary skill may obtain the average lateral feature size 44 and average height 46 by taking an image of the primary surface 18 and measuring the maximum dimension of a sampling of at least ten features. In other instances, larger sample sizes can be employed, as judged appropriate by those skilled in the field of the disclosure to obtain statistically significant results. Accordingly, the terms “average lateral feature size” and “average height” of the plurality of hillocks 36 are used interchangeably in the disclosure with the terms “average maximum lateral feature size” and “average maximum height”, or like terms.

[0037] In embodiments of the textured glass article 10 shown in FIG. 2, the average lateral feature size 44 of the plurality of hillocks 36 is greater than or equal to about 0.01 μm. In some implementations, the average lateral feature size 44 can be from 0.01 μm to 20 μm, 0.01 μm to 10 μm, 0.1 μm to 10 μm, 0.1 μm to 5 μm, 0.1 μm to 3 μm, 0.2 μm to 2 μm, or any lateral feature sizes or sub-ranges within these ranges. For example, the average lateral feature size 44 of the plurality of hillocks 36 can be 0.01 μm, 0.05 μm, 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 15 μm, 20 pm, and all lateral feature sizes within these lateral sizes.

[0038] According to some embodiments of the textured glass article 10 shown in FIG. 1, the average height 46 of the plurality of hillocks 36 is greater than or equal to about 1 nm. In some implementations, the average height 46 can be from 1 nm to 10000 nm, 1 nm to 5000 nm, 1 nm to 1000 nm, 5 nm to 5000 nm, 5 nm to 1000 nm, 5 nm to 200 nm, or any average height or sub-range within these ranges. For example, the average height 46 of the plurality of hillocks 36 can be 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 125 nm, 150 nm, 175 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1000 nm, 2000 nm, 3000 nm, 4000 nm, 5000 nm, 7500 nm, 10000 nm, and all average heights within these average height values.

[0039] According to implementations of the textured glass article 10 depicted in FIG. 1, the article is characterized by a low level of sparkle. In general, the roughness associated with its surface features 34 can begin to act like a plurality’ of lenses that generates an image artifact called “sparkle”. Display “sparkle” or “dazzle” is a generally undesirable side effect that can occur when introducing antiglare or light scattering surfaces into a pixelated display system such as, for example, an LCD, an OLED, touch screens, or the like, and differs in type and origin from the type of “sparkle” or “speckle” that has been observed and characterized in projection or laser systems. Sparkle is associated with a very fine grainy appearance of the display and may appear to have a shift in the pattern of the grains with changing viewing angle of the display. Display sparkle may be manifested as bright and dark or colored spots at approximately the pixel -level size scale.

[0040] As generally depicted in FIG. 1, the textured surface 32 of the glass article 10 can be configured to minimize sparkle. In some embodiments, the textured surface 32 is configured to minimize sparkle, while maintaining a reduced glare function (e.g., with regard to DOI, as outlined in greater detail later in this disclosure) suitable for display device applications. According to some embodiments, the textured surface 32 of the textured glass article 10 is configured such that the article is characterized by a sparkle of 1% or less, as measured by total pixel power distribution (PPD). In other aspects, the textured glass articles 100 of the disclosure can be configured with a sparkle of 1% or less, 0.9% or less, 0.8% or less, 0.7% or less, 0.6% or less, 0.5% or less, 0.4% or less, 0.3% or less, 0.2% or less, 0.1% or less, and all sparkle levels and sparkle sub-ranges between these upper limits, as measured by a PPD. For example, the textured glass article 10 can have a sparkle of 1%, 0.75%, 0.5%, 0.25%, 0.1%, 0.075%, 0.05%, 0.025%, and all sparkle levels between these values.

[0041] As used herein, the terms ‘‘pixel power deviation” and ‘‘PPD” refer to the quantitative measurement for display sparkle. Further, as used herein, the term “sparkle” is used interchangeably with “pixel power deviation” and “PPD ” PPD is calculated by image analysis of display pixels according to the following procedure. A grid box is drawn around each LCD pixel. The total power within each grid box is then calculated from charge-coupled device (CCD) camera data and assigned as the total power for each pixel. The total power for each LCD pixel thus becomes an array of numbers, for which the mean and standard deviation may be calculated. The PPD value is defined as the standard deviation of total power per pixel divided by the mean power per pixel (times 100). The total power collected from each LCD pixel by the eye simulator camera is measured and the standard deviation of total pixel power deviation (PPD) is calculated across the measurement area, which typically comprises about 30x30 LCD pixels.

[0042] The details of a measurement system and image processing calculation that are used to obtain PPD values are described in U.S. Patent No. 9,411, 180 (the ' 180 patent) entitled “Apparatus and Method for Determining Sparkle,” the salient portions of which that are related to PPD measurements are incorporated by reference herein in their entirety . Further, unless otherwise noted, the SMS-1000 system (Display-Messtechnik & Systeme GmbH & Co. KG) is employed to generate and evaluate the PPD measurements of this disclosure. The PPD measurement system includes: a pixelated source comprising a plurality of pixels (e.g., a Lenovo Z50 140 ppi laptop), wherein each of the plurality of pixels has referenced indices i and j; and an imaging system optically disposed along an optical path originating from the pixelated source. The imaging system comprises: an imaging device disposed along the optical path and Slaving a pixelated sensitive area comprising a second plurality' of pixels, wherein each of the second plurality of pixels are referenced with indices m and n\ and a diaphragm disposed on the optical path between the pixelated source and the imaging device, wherein the diaphragm has an adjustable collection angle for an image originating in the pixelated source. The image processing calculation includes: acquiring a pixelated image of the transparent sample, the pixelated image comprising a plurality of pixels; determining boundaries between adjacent pixels in the pixelated image; integrating within the boundaries to obtain an integrated energy for each source pixel in the pixelated image; and calculating a standard deviation of the integrated energy for each source pixel, wherein the standard deviation is the power per pixel dispersion. As used herein, all “PPD” and "‘sparkle” values, attributes and limits are calculated and evaluated with a test setup employing a display device having a pixel density of 140 pixels per inch (PPI) (also referred herein as “PPDuo”). Further, unless otherwise noted herein, sparkle is reported in units of “%” to denote the percentage of sparkle observed on a display device having a pixel density of 140 pixels per inch ,

[0043] Referring again to the textured glass article 10 depicted in FIG. 1, the article can also be configured for optimal antiglare performance, as manifested by low Distinctness-of-Image (DOI) values. As used herein, “DOI” is equal to 100*(Rs- Ro.3")/Rs, where Rs is the specular reflectance flux measured from incident light (at 30° from normal) directed onto a textured surface 32 of a textured glass article of the disclosure and Row is the reflectance flux measured from the same incident light at 0.3° from the specular reflectance flux, Rs. Unless otherwise noted, the DOI values and measurements reported in this disclosure are obtained according to the ASTM D5767-18 Standard Test Method for Instrumental Measurement of Distinctness-of-Image (DOI) Gloss of Coated Surfaces using a Rhopoint IQ Gloss Haze & DOI Meter (Rhopoint Instruments Ltd.). Notably, the textured glass articles 100 of the disclosure can exhibit low sparkle (e.g., less than 1%) without significant reductions in antiglare performance, as manifested in low DOI values. In implementations, the textured glass articles 100 of the disclosure are believed to exhibit a DOI of 99.5% or less. In other embodiments, the textured glass articles 100 of the disclosure are believed to exhibit a DOI of less than 99.5%, 99%, 95%, 90%, 85%, 80%, 75%, 70%, and all DOI levels between these upper limits. [0044] According to implementations of the textured glass articles 100 depicted in FIG. 1 of the ' 180 patent, the articles can be characterized by a haze of 30% or less. In other implementations, for particular applications, textured glass articles 100 consistent with the principles of this disclosure can be fabricated with haze levels up to 90%. In further implementations, the textured glass articles 100 can be characterized with haze levels ranging from 3% to 90%, from 3% to 30%, from 1% to 90%, from 3% to 30%, from 1% to 10%, from 0.1% to 100%, from 0.1% to 30%, from 0.1% to 10%, from 0.02% to 0.1%, and all haze levels and haze sub-ranges between these haze ranges.

[0045] According to implementations of the textured article 100 depicted in FIG. 1 of the ' 180 patent, the article can be characterized with a gloss of from about 30 to 100, 30 to 90, 40 to 100, 40 to 90, 50 to 100, 50 to 90, and all gloss values and gloss sub-ranges between these gloss levels, as measured at a 20° incident angle. According to implementations of the textured article 100 depicted in FIG. 1 of the ' 180 patent, the article can be characterized with a gloss of from about 50 to 150, 50 to 120, 60 to 150, 60 to 120, 70 to 150, 70 to 120, and all gloss values and gloss sub-ranges between these gloss levels, as measured at a 60° incident angle. According to implementations of the textured article 100 depicted in FIG. 1 of the ' 180 patent, the article can be characterized with a gloss (as measured under ASTM D523) of from about 50 to 150, 50 to 120, 60 to 150, 60 to 120, 70 to 150, 70 to 120, 90 to 150, 90 to 120, and all gloss values and gloss sub-ranges between these gloss levels, as measured at a 85° incident angle

[0046] In one or more embodiments, the average light transmittance of the textured glass article 10 depicted in FIG. 1 can be at least 70%, 75%, 80%, 85%, 90%, 95%, or any transmittance level or range at or above these transmittance levels, as measured in the visible spectrum from about 400 nm to about 800 nm. For example, the average light transmittance of the glass article 10 can be 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or any transmittance level between these transmittance levels, as measured in the visible spectrum from about 400 nm to about 800 nm.

[0047] ‘ ‘Gloss,” “gloss level,” or like terms refer to, for example, surface luster, brightness, or shine, and more particularly to the measurement of specular reflectance calibrated to a standard (such as, for example, a certified black glass standard) in accordance with ASTM procedure D523, the contents of which are incorporated herein by reference in their entirety. Common gloss measurements are typically performed at incident light angles of 20°, 60°, and 85°, with the most commonly used gloss measurement being performed at 60°. Unless otherwise noted, the amount of gloss is reported in this disclosure with either of the following interchangeable designations under ASTM D523: “standard gloss units (SGU)” (i.e., “a gloss from 30 SGU to 100 SGU”) or a unit-less number (i.e., a “gloss from 30 to 100”).

[0048] As used herein, the terms “transmission haze” and “haze” refer to the percentage of transmitted light scattered outside an angular cone of about ± 2.5° in accordance with ASTM procedure DI 003, entitled “Standard Test Method for Haze and Uuminous Transmittance of Transparent Plastics,” the contents of which is incorporated by reference herein in its entirety. For an optically smooth surface, transmission haze is generally close to zero (i.e., 0%). Unless otherwise noted herein, haze values are reported in units of “%” to denote the percentage of haze measured according to ASTM D1003.

[0049] As used herein, the term “transmittance” is defined as the percentage of incident optical power within a given wavelength range transmitted through a material (e.g., the article, the substrate or the optical fdm or portions thereof). Unless otherwise noted herein, transmittance values are reported in units of “%” to denote the percentage of incident optical power measured through the material within a specified wavelength range. The term “reflectance” is similarly defined as the percentage of incident optical power within a given wavelength range that is reflected from a material (e.g., the article, the substrate, or the optical film or portions thereof). Reflectance may be measured as a single side reflectance (also referred to herein as “first surface reflectance”) when measured at the first primary surface of a substrate only of the article, such as through using index-matching oils on the back surface coupled to an absorber, or other known methods.

[0050] Referring again to FIG. 2, the glass substrate 30 of the textured glass article 10 can be configured with a multi-component glass composition having about 40 mol% to 80 mol% silica and a balance of one or more other constituents, e.g., alumina, calcium oxide, sodium oxide, boron oxide, etc. In some implementations, the bulk composition of the glass substrate 30 is selected from the group consisting of aluminosilicate glass, a borosilicate glass and a phosphosilicate glass. In other implementations, the bulk composition of the glass substrate 30 is selected from the group consisting of aluminosilicate glass, a borosilicate glass, a phosphosilicate glass, a soda lime glass, an alkali aluminosilicate glass, and an alkali aluminoborosilicate glass. In further implementations, the glass substrate 30 is a glass-based substrate, including but not limited to, glass-ceramic materials that comprise a glass component at about 90% or greater by weight and a ceramic component.

[0051] In one embodiment of the textured glass article 10 depicted in FIG. 2, the glass substrate 30 has a bulk composition that comprises an alkali aluminosilicate glass that comprises alumina, at least one alkali metal and, in some embodiments, greater than 50 mol %, SiO₂, in other embodiments, at least 58 mol %, and in still other embodiments, at least 60 mol % SiO₂, wherein the ratio (AI2O3 (mol%) + B2O3 (mol%)) / T alkali metal modifiers (mol%) > 1, where the modifiers are alkali metal oxides. This glass, in particular embodiments, comprises, consists essentially of, or consists of: about 58 mol % to about 72 mol % SiO₂; about 9 moi % to about 17 mol % AI2O3; about 2 moi % to about 12 mol % B2O3; about 8 mol % to about 16 mol % NazO; and 0 mol % to about 4 mol % KzO, wherein the ratio (AI2O3 (mol%) + B2O3 (mol%)) / T alkali metal modifiers (mol%) > 1 , where the modifiers are alkali metal oxides.

[0052] In another embodiment of the textured glass article 10, as shown in FIG. 2, the glass substrate 30 has a bulk composition that comprises an alkali aluminosilicate glass comprising, consisting essentially of, or consisting of: about 61 mol % to about 75 mol % SiO₂; about 7 moi % to about 15 mol % AizOz; 0 moi % to about 12 moi % B2O3; about 9 mol % to about 21 mol % NazO; 0 mol % to about 4 mol % KzO; 0 mol % to about 7 mol % MgO; and 0 mol % to about 3 mol % CaO.

[0053] In yet another embodiment, the glass substrate 30 has a bulk composition that comprises an alkali aluminosilicate glass comprising, consisting essentially of, or consisting of: about 60 mol % to about 70 mol % SiO₂.; about 6 mol % to about 14 mol % Al 2O3; 0 mol % to about 15 mol % B2O3; 0 mol % to about 15 mol % LizO; 0 mol % to about 20 mol % NazO; 0 mol % to about 10 mol % KzO; 0 mol % to about 8 mol % MgO; 0 mol % to about 10 mol % CaO; 0 mol % to about 5 mol % ZrO2; 0 mol % to about 1 mol % SnO2; 0 mol % to about 1 mol % CeOz; less than about 50 ppm AszOz; and less than about 50 ppm SbzOz; wherein 12 mol % LizO + NazO + KzO 20 mol % and 0 mol % MgO + Ca 10 mol %.

[0054] In still another embodiment, the glass substrate 30 has a bulk composition that comprises an alkali aluminosilicate glass comprising, consisting essentially of, or consisting of: about 64 mol % to about 68 mol % SiO₂.; about 12 mol % to about 16 mol % NazO; about 8 mol % to about 12 mol % AI2O3; 0 mol % to about 3 mol % B2O3; about 2 mol % to about 5 mol % K2O; about 4 mol % to about 6 mol % MgO; and 0 mol % to about 5 mol % CaO, wherein: 66 mol % ~ SiO₂ + B2O3 + CaO 69 mol %; Na2.O + K2O + B2O3 + MgO + CaO + SrO > 10 mol %; 5 mol % MgO + CaO + SrO 8 mol %; (NazO + B2O3) - AI2O3 ~ 2 mol %; 2 mol % Na₂O - AI2O3 6 mol %; and 4 mol % ( Na₂O + KzO) - AI2O3 — 10 mol %. [0055] In other embodiments, the glass substrate 30 has a bulk composition that comprises SiO₂, AlzOj, P2O5, and at least one alkali metal oxide (RzO), wherein 0.75 > [(P2O5 (mol %) + R2O (mol %)) / M2O3 (mol %)] Si 1.2, where M2O3 = AI2O3 + B2O3. In some embodiments, [(P2O5 (mol %) + R2O (mol %)) / MzOs Onol %)] = 1 and, in some embodiments, the glass does not include B?O3 and M2O3 ^::: AI2O3. The glass substrate comprises, in some embodiments: about 40 to about 70 mol % SiO?.; 0 to about 28 mol % B2O3; about 0 to about 28 mol % AI2O3; about 1 to about 14 mol % P2O5; and about 12 to about 16 mol % R2O. In some embodiments, the glass substrate comprises: about 40 to about 64 mol % SiO?; 0 to about 8 mol % B2O3; about 16 to about 28 mol % AI2O3; about 2 to about 12 moi % P2O5; and about 12 to about 16 mol % R2O. The glass substrate 30 may further comprise at least one alkaline earth metal oxide such as, but not limited to, MgO or CaO.

[0056] In some embodiments, the glass substrate 30 has a bulk composition that is substantially free of lithium; i.e., the glass comprises less than 1 mol % IJ2O and, in other embodiments, less than 0.1 mol % IJ2O and, in other embodiments, 0.01 mol % LiiO, and in still other embodiments, 0 mol% Li2O. In some embodiments, such glasses are free of at least one of arsenic, antimony, and barium; i.e., the glass comprises less than 1 mol % and, in oilier embodiments, less than 0.1 mol %, and in still other embodiments, 0 mol % of AS2O3, Sb2.03, and/or BaO.

[0057] In other embodiments of the textured glass article 10 depicted in FIG. 2, the glass substrate 30 has a bulk composition that comprises, consists essentially of or consists of a glass composition Coming® Eagle XG® glass, Coming® Gorilla® glass, Coming® Gorilla® Glass 2, Coming® Gorilla® Glass 3, Coming® Gorilla® Glass 4 or Coming® Gorilla® Glass 5. In some implementations of the textured glass article 10 depicted in FIG. 2, the glass substrate 30 can have any of the following compositions denoted as “Glass A”, “Glass B”, “Glass C”, “Coming® Eagle XG® Glass” or “Coming® Gorilla® Glass 5”. Glass A has the following composition (given in mol%): 63.65% SiCE; 16.19% AI2O3; 2.67% P2O5; 0.38% B2O3; 0.33% MgO; 8.07% Li₂O; 8.11% Na₂O; 0.52% K₂O; 0.05% SnO₂; and 0.02% Fe₂O₃. Glass B has the following composition (given in mol%): 63.59% SiCh; 15.07% AI2O3; 2.51% P2O5; 2.40% B2O3; 5.95% Li₂O; 9.26% Na₂O; 0.04% SnO₂; and 1.18% ZnO. Glass C has the following composition (given in mol%): 70.6% SiCh; 12.7% AI2O3; 2% B2O3; 8.2% Li2O; 2.4% Na2O; 2.9% MgO; 0.05% SnO2; and 0.9% ZnO. Coming® Eagle XG® glass has the following composition (given in mol%): 67.71% SiO2; 11.03% AI2O3; 9.65% B2O3; 2.26% MgO; 8.81% CaO; and 0.54% SrO. Coming® Gorilla® Glass 5 has the following composition (given in mol%): 63.63% SiO2; 15.64% AI2O3; 2.47% P2O5; 6.22% Li2O; 10.82% Na₂O; 0.07% SnO₂; and 1.16% ZnO. [0058] Referring now to FIG. 3, a method 60 for preparing the textured glass article 10 is demonstrated as a process diagram. As previously discussed, the method 60 may provide for the textured surface 32 of the glass substrate 30 to be provided by exposing the glass article 10 to a thermochemical treatment process. The process outlined by the method 60 provides for both chemical strengthening and surface etching of the glass article 10 as a result of exposure to a single molten salt bath. For example, the disclosure may provide for the etching or generation of the textured surface 32 and the exchange of ions in the primary surfaces 18 to effectuate a layer under compressive stress to have a depth D. The method 60 provides for concurrent operation of the chemical strengthening in combination with the generation of the textured surface 32 without the use of hydrofluoric acid.

[0059] The method 60 may begin with step 62 by providing the molten salt bath 64 with bath composition 66 comprising nitrate salt and silicic acid and heating 68 the molten salt bath 64 to a treatment temperature that is generally between 350°C and 500°C and may more specifically range from 410°C to 490°C. Note that the specific exemplary compositions and ranges of constituent parts forming the molten salt bath 64 are discussed later following the overview of the method 60. Once the molten salt bath 64 reaches the treatment temperature, air 70 (e.g., atmospheric air) with a controlled level of humidity is supplied into the bath composition 66 in a molten state. The air 70 may be supplied and distributed through the molten etchant salt bath 64 via a bubbling process that delivers the air 70 into the molten salt bath 64 as shown in step 72. The delivery of the air 70 into the molten salt bath 64 may generally be referred to as an aging or conditioning step 72 of the method 60. The conditioning process may be applied over a predetermined conditioning time that may vary based on the desired level of haze or texture on the textured glass article 10 and may generally refer to the steps leading to the submersion of the substrate 30 into the molten salt bath 64 as later discussed. The delivery of the air 70 at the controlled humidity level may provide for a controlled introduction of water molecules into the molten salt bath 64 and the corresponding conditioning time may be a time necessary to achieve a steady state condition of the water molecules. As identified by the inventors, the introduction of the humidity controlled air 70 into the molten salt bath 64 may be a significant factor in providing the controlled formation of the textured surface 32 as discussed herein.

[0060] Additionally, in step 74, while the air 70 is delivered into the molten salt bath 64, a lithium salt 75 may be gradually or sequentially added over temporally spaced intervals of the conditioning time. For example, the lithium salt 75 may be added in four or more evenly divided portions to achieve a desired total percent by weight of lithium salt in combination with the additional components initially heated to a predetermined temperature to prepare the molten salt bath 64 in step 62. In general, the interval time for adding the portions of the lithium salt 75 may be spaced over a period exceeding at least 1 hour between portions. More specifically, the time between portions of doses of the lithium salt 75 may be at least 2- 4 hours or separated at least three hours in time. In some cases, the additional of one or more portion of the lithium salt 75 may be separated over a time exceeding 8, 10, or even 12 hours. The delayed addition of the portions of the lithium salt 75 to the molten salt bath 64 may provide for an even distribution of smaller lithium salt crystals suspended in the molten salt bath 64 rather than sinking to the bottom of the tank. The suspension of the lithium salt 75 in the molten salt bath 64 may assist in the uniform formation of haze over the primary surface 18 via an initial ion exchange process when the substrate 30 is submerged in the molten salt bath 64.

[0061] At the conclusion of the conditioning time of step 72 and following the addition of the lithium salt 75 in step 74, the method 60 may continue to step 76, which may optionally provide for the substrate 30 to be heated 78 to a preheat temperature prior to submersion into the molten salt bath 64. The preheat temperature may be similar to the temperature of the molten salt bath 64 to limit thermal shock to the substrate 30 that may otherwise result from rapid temperature adjustment associated with immersion in the molten salt bath 64. For example, the substrate may be gradually heated to the treatment temperature over a period of 10-60 minutes, which may generally be between 350°C and 500°C and may more specifically range from 410°C to 490°C. Once the substrate 30 reaches the treatment temperature, the method may continue to step 84, wherein the substrate 30 is submerged in the molten salt bath 64.

[0062] Following the conditioning step 72 and the addition of the lithium salt 75 in step 74 the bath composition 66 is completed and the molten salt bath 64 may be referred to as a conditioned salt bath 80. At such a time, the substrate 30 may be submerged 82 in the conditioned salt bath 80 to begin a chemical strengthening and etching process (84). The air 70 with the controlled humidity level may continue to be supplied into the conditioned salt bath 80 for all or part of step 84. The submersion of the substrate 30 in the conditioned salt bath 80 may initiate an ion exchange process that provides for the generation of the textured surface 32 as well as chemical strengthening of the substrate 30. As previously discussed, the chemical strengthening provides for improved compressive strength referred to as the “depth of layer” denoted in FIG. 2 as the depth D. The submersion of the substrate 30 in step 84 may extend for a duration ranging from approximately 30 minutes to 24 hours and in some cases may range from approximately 4 to 18 hours. In an exemplary embodiment, the ion exchange process provided by submersion of the substrate 30 in the conditioned salt bath 80 may range from approximately 6 to 14 hours and in some cases may be approximately 7 to 10 hours. Each of the durations may vary based on the level of haze of the textured surface 32 as well as the desired strength properties provided by the depth of layer of the compressive stress region 50.

[0063] Following the completion of the ion exchange process and the texturing or etching of the primary surfaces 18 to provide the textured surface 32, the substrate 30 may be withdrawn from the conditioned salt bath 80 and allowed to cool in step 86. Once the textured glass article 10 resulting from the treatment in the conditioned salt bath 80 is cooled, the article 10 may be rinsed with deionized water and/or an acid solution (e.g., citric acid solution) to remove surface films in step 88 to complete the treatment and preparation procedure of the textured glass article 10. By providing the textured surface 32 as well as chemical strengthening of the substrate 30 in the conditioned salt bath 80 without separate etching steps, the method 60 provides for significant improvement in steps necessary to provide the textured glass article 10 while maintaining the beneficial characteristics of uniform haze, compressive strength, and depth of layer.

[0064] The method 60 demonstrated in FIG. 3 may utilize a variety of chemicals and additives to provide the conditioned salt bath 80. Additionally, the level of humidity of the air 70 supplied into the molten salt bath 64 may be adjusted to provide varying levels of haze for the textured surface 32. As previously discussed, the bath composition 66 may primarily comprise nitrate salt (e.g., NaNOs, KNOs, LiNOs), sodium ash (e.g., NaCOs), and silicic acid (Si(OH)4). Additionally, the lithium salt 75 component (e.g., LiNO3, Li2CO3, Li2SO4 and LiCl) of the nitrate salt may be added gradually or sequentially three or more separate times, which may be separated in time by 3 or more hours. The addition of the lithium salt 75 as previously discussed in step 74 may be completed concurrently with the conditioning of the molten salt bath 64 as provided in step 72. Accordingly, the conditioning time of step 72 may overlap or correspond with the distributed time over which the portions of the lithium salt 75 are added to the molten salt bath 64. In general, the ions introduced in the exchange process and forming the molten salt bath 64 may correspond to monovalent alkali metal cations, such as Li⁺ (when present in the glass), Na⁺, K⁺, Rb⁺, and Cs* In some cases, the monovalent cations in the surface layer of the glass substrate 30 may be replaced with monovalent cations other than alkali metal cations, such as Ag⁺ or the like. [00651 In an exemplary embodiment, the bath composition 66 may vary in proportions and may include 20% to about 90% nitrate salt including 0.1% to 2.5% lithium salt added in distributed portions as previously discussed. Additionally, the bath composition may include approximately 0.1% to 10% silicic acid by weight. An additional example of the bath composition 66 may include 60% to about 80% NaNO3; 15% to about 35% KNO3; 3% to 7% Na2CO3; 0.5% to 4% LiNO3; and 0.2% to 1.5% silicic acid. In some cases, the potassium and sodium components of the nitrate salt may be exchanged such that the bath composition 66 comprises 65% to about 85% KN03; 10% to about 30% NaNO3; 3% to 7% Na2CO3; 0.5% to 4% LiNO3; and 0.2% to 1.5% silicic acid. These compositions and ranges of component ingredients may provide for the beneficial formation of the textured surface 32 in combination with the chemical strengthening. Additionally, as later discussed in reference to FIGS. 6 and 7, the humidity of the air 70 supplied into the molten salt bath 64 to provide the conditioned salt bath 80 may vary from approximately 5% to 100% to effectuate meaningful variations in the haze of the textured surface 32.

[0066] The method 60 may generally provide for the compressive stress region 50, when strengthened by ion exchange, that has a compressive stress of at least 200 MPa (i.e., a minimum compressive stress (CS)), and the region under compressive stress extends to the depth D, from 5 μm to 200 μm below the primary surface 18. According to some embodiments of the textured glass article 10, the compressive stress region 50 has a minimum CS of 100 MPa, 150 MPa, 200 MPa, 250 MPa, 300 MPa, 350 MPa, 400 MPa, 450 MPa, 500 MPa, 600 MPa, 700 MPa, 800 MPa, 900 MPa, 1000 MPa, or any minimum CS value between levels. Further, according to some implementations of the textured glass article 10, the compressive stress region 50 extends to a depth D such that it can be characterized with a depth of compression (DOC) from 1 μm to 300 μm, 1 μm to 2.00 μm, 5 μm to 300 μm, 5 μm to 200 μm, 5 μm to 100 pm, and all DOC values and sub-ranges between these DOC ranges.

[0067] Referring to FIGS. 4A, 4B, and 4C, example images are shown depicting a first sample substrate 90a, a second sample substrate 90b, and a third sample substrate 90c. Each of the sample substrates 90a, 90b, 90c w ere clear aluminosilicate glass substrates prepared in the molten salt bath 64 at a temperature of 430°C. The glass substrates had a composition of 64 mol% SiO2, 16 mol% AI2O3, 11 mol% Na2O, 6 mol% Li2O, 1 mol% ZnO, 2.5 mol% P2Osand 0.05 mol% SnO2. To identify the impact of the lithium salt (e.g., % L1NO3) on the textured surface 32, each of the first sample substrate 90a, the second sample substrate 90b, and the third sample substrate 90c was prepared in the molten salt bath 64 with a composition 66 of 25% NaNOs, 75% KNOs, and 0.5% silicic acid. The molten salt bath 64 for second sample substrate 90b included 0.5% lithium salt (e.g., 0.5% LiNCh) and the third sample substrate 90c included a lithium salt (e.g., 1% LiNOs) in addition to the other nitrate salts and silicic acid (0.5%). The pictures of the sample substrates 90a, 90 b, 90c were taken under an edge light illumination. As shown, the inclusion of the 0.5% lithium salt caused the second sample substrate 90b to include reasonable haze formation. When further compared to the third sample substrate 90c, the inclusion of the 1% lithium salt provided additional benefits in the level or percent of haze formation and also the consistency of the haze formation over forming the textured surface 32. Accordingly, the beneficial haze formation of the second and third sample substrates 90b, 90c may be provided by the combination of the silicic acid with the lithium salt in the molten salt bath 64.

[0068] Referring now to FIGS. 5A and 5B, comparative results are shown demonstrating the effects of silicic acid in the molten salt bath 64 on a first sample substrate 100a, second sample substrate 100b, third sample substrate 100c, and fourth sample substrate lOOd. Each of tlie sample substrates 100a, 100b, 100c, lOOd demonstrated was clear aluminosilicate glass having the same composition as sample substrates 90a, 90b, 90c, The first and second sample substrates 100a, 100b were prepared in the molten salt bath 64 with a composition 66 of 20% NaNOs, 5% Na₂CO₃, 75% KNO3 and 1.0% L1NO3 at 430° C for 8 hours. The third and fourth sample substrates 100c, lOOd were prepared in the molten salt bath 64 with a composition 66 of 20% NaNOs, 5% Na₂CO₃, 75% KNO₃ and 1.0% L1NO3 at 460°C for 4 hours. Each of the examples on the right, the second and fourth sample substrates 100b and lOOd, further included 0.5% silicic acid in the molten salt bath 64 and each included significant increases in haze and uniformity, which provide improved antiglare results. Each of these conditions were achieved while also providing improved strength of the compressive stress region 50.

[0069] Referring now to FIGS. 6, 7, and 8, the relationship of the conditioning step 72 or an aging step to the development of the textured surface 32 is discussed in further detail. Each of the conditioning or aging steps generally provide for the exposure of the molten salt bath 64 or the substrate 30 to humidity, which may be present in the local environment or actively supplied via a bubbler, steam supply, humidifier, etc. as discuss in the method 60. In each case, the conditioning of the substrate 30 and/or the molten salt bath 64 provides further beneficial haze formation on the substrates as presented in the following examples.

[0070] FIG. 6 demonstrates photographs of a first sample substrate 110a and a second sample substrate 110b. Each of the substrates was treated in a molten salt bath 64 with a composition 66 comprising 20% NaNCh. 5% Na2COs, 75% KNOs, 1.0% LiNOs, and 0.5% silicic acid at 460°C for 4 hours. The first sample substrate 110a was not pretreated while the second sample substrate 110b was exposed to a steam pretreatment at 85°C with 85% humidity. The differences between the haze of the first sample substrate 110a and the second sample substrate 110b are more subtle in the photographic depictions than observed. However, a number of haze variations 112 or texture inconsistencies are identified in FIG. 6 and by comparison, the first sample substrate 110a that was not pretreated at the controlled humidity has a significantly increased number of the haze variations than the second sample substrate 110b. Accordingly, pretreatment in the form of exposure of the substrate 30 to moisture prior to submersion in the molten salt bath 64 is an alternate method to improve the haze and antiglare properties of the textured glass article 10.

[0071] Referring to FIG. 7, another example of conditioning or aging the molten salt bath 64 is shown. A first sample substrate 120a and a second sample substrate 120b were treated in the molten salt bath 64 with a composition comprising 20% NaNOs, 5%Na2COs, 75% KNO3, 1.0% LiNCh, and 0.5% silicic acid at 460°C for 4 hours. The first sample substrate 120a was treated in the molten salt bath 64 within a short time period (e.g., less than 30 minutes) following the melting of the salts. In contrast, the second sample substrate 120b was treated two days after the melting of the salts in the molten salt bath 64. Accordingly, the molten salt bath 80 was conditioned as a result of aging the molten salt bath 64 by exposure to environmental conditions near the location of the bath 64. As a result, the second sample substrate 120b demonstrates superior development of haze compared to the first substrate 120a.

[0072] As shown in FIG. 8, test data from substrates of aluminosilicate glass (having the same glass composition as sample substrates 90a, 90b, 90c) is shown demonstrating the comparative haze formation of the textured surfaces 32 of the textured glass article 10. Each of the samples was treated in a molten salt bath 64 including 538g NaNCh, 203g KNO3, 39g Na2CC>3, 4.0g Silicic acid, andl9.5g LiNCE. As previously discussed, the lithium salt was added over an extended period in small, evenly proportioned quantities (e.g., ~4 g of 0.5 wt%) every 3 hours. The three hour separation between additions was the minimum for the test and in some cases, the portions were added over time intervals that exceeded 3 hours up to 12 hours. The comparative effects of the aging or conditioning of the molten salt bath are demonstrated in the bar graph of FIG. 8.

[0073] Each of the results in FIG. 8 demonstrates the result of conditioning or aging the molten salt bath 64 to specific conditions for a period of approximately 12 hours before the treatment of the substrate 30. In each case, the molten salt bath 64 was heated to 430°C and exposed to the described conditions. As demonstrated, a first molten salt bath received humidified air with 100% humidity bubbled into the molten salt for 12 hours and the substrate resulted with approximately 21% haze after 8 hours of treatment. A second molten salt bath received humidified air with 80% relative humidity bubbled into the molten salt for 12 hours and the substrate resulted with approximately 13% haze after 8 hours of treatment. A third molten salt bath received exposed to humidified air with 50% relative humidity bubbled into the molten salt for 12 hours and the substrate resulted with approximately 13% haze after 8 hours of treatment. A fourth molten salt bath was exposed to dry air relative humidity for 12 hours and the substrate resulted with approximately 0.3% haze after 8 hours. Finally, a fifth molten salt bath was exposed to stagnant environment air for 12 hours and the substrate resulted with approximately 1.5% haze after 8 hours. Accordingly, the controlled addition of water molecules into the molten salt bath 64 was a controlling factor in the aging or condition process and the resulting surface texture 32.

[0074] According to a first aspect, a method of making a glass article is disclosed. The method includes providing a glass substrate comprising a thickness and a primary surface and treating a molten etchant bath by supplying humidified air with a controlled humidity level between 10% and 100% into the molten etchant bath for a predetermined time, thereby providing a treated etchant bath. The method further includes adding lithium salt to the treated etchant bath providing the treated etchant bath that includes (by weight): (a) 20% to about 90% nitrate salt, (b) 0.1% to 10% silicic acid, and (c) 0.1% to 25% lithium salt. The method further includes submerging the glass substrate in the treated molten etchant bath for an etching duration, wherein the submerging forms a haze over the primary surface of the glass substrate.

[0075] According to a second aspect, the first aspect is provided, wherein the treating of the etchant bath by supplying the humidified air is continued through a heating of the treated etchant bath and the submerging of the glass substrate.

[0076] According to a third aspect, the first aspect is provided, wherein the lithium salt is gradually added over the predetermined time.

[0077] According to a fourth aspect, the third aspect is provided, wherein the lithium salt is added in equal proportion at regular intervals over the predetermined time.

[0078] According to a fifth aspect, the first aspect is provided, wherein the predetermined time for the treating of the etchant bath is a treatment duration of 30 minutes to 24 hours. [0079] According to a sixth aspect, the first aspect is provided, wherein the predetermined time for the treating of the etchant bath is a treatment duration of 4 hours to 18 hours.

[0080] According to a seventh aspect, the first aspect is provided, wherein the predetermined time for the treating of the etchant bath is a treatment duration of 8 hours to 14 hours.

[0081] According to an eighth aspect, the first aspect is provided, where in the nitrate salt is from a group consisting of KNOs and NaNCf .

[0082] According to a ninth aspect, the first aspect is provided, wherein the lithium salt is selected from the group consisting of LiNOs, I^COs, Li2SO4 and LiCl.

[0083] According to a tenth aspect, the first aspect is provided, wherein the etchant bath further comprises 3% to 10% Na2COs.

[0084] According to a eleventh aspect, the first aspect is provided, wherein the etchant bath comprises (by weight): (a) 60% to about 80% NaNOs; (b) 15% to about 35% KNO3; (c) 3% to 7% Na2CC>3; (d) 0.5% to 4% LiNCh; and (e) 0.2% to 1.5% silicic acid.

[0085] According to a twelfth aspect, the first aspect is provided, wherein the etchant bath comprises (by weight): (a) 65% to about 85% KNO3; (b) 10% to about 30% NaNCh; (c) 3% to 7% Na2CC>3; (d) 0.5% to 4% LiNCh; and (e) 0.2% to 1.5% silicic acid.

[0086] According to a thirteenth aspect, the first aspect is provided, wherein the etchant bath is treated by bubbling the humidified air into the etchant bath.

[0087] According to a fourteenth aspect, the first aspect is provided, wherein the humidity level of the air is from 50% to 100%.

[0088] According to a fifteenth aspect, the first aspect is provided, further comprising cooling the glass substrate and rinsing the glass substrate with deionized water and a citric acid solution.

[0089] According to a sixteenth aspect, the first aspect is provided, wherein the submerging step is further conducted such that the glass substrate further comprises a compressive stress region that extends from the primary surface to a selected depth, and further wherein the compressive stress region comprises a minimum compressive stress (CS) of 200 MPa and a depth of compression (DOC) from 5 μm to 200 μm.

[0090] According to a seventeenth aspect, the first aspect is provided, wherein the glass substrate comprises a composition selected from the group consisting of an aluminosilicate glass, a borosilicate glass, a phosphosilicate glass, a soda lime glass, an alkali aluminosilicate glass, and an alkali aluminoborosilicate glass. [0091] According to a eighteenth aspect, the first aspect is provided, further comprising heating an etchant bath to an etching temperature from 350°C to 500°C, thereby providing the molten etchant bath.

[0092] According to a nineteenth aspect, the first aspect is provided, wherein the etching temperature is from 410°C to 490°C.

[0093] According to a twentieth aspect, the first aspect is provided, wherein the etching duration is from 10 minutes to 1000 minutes.

[0094] According to a twenty-first aspect, a display system is provided that includes the glass substrate having at least one roughened surface prepared by the method of the first aspect. The glass substrate includes a haze of less than about 25; and a surface roughness (Ra) of about 5 nm to about 500 nm.

[0095] According to a twenty-second aspect, the twenty-first aspect is provided, wherein the transmittance is greater than 90%.

[0096] According to a twenty-third aspect, the twenty-first aspect is provided, wherein the haze over the roughened surface varies less than 2%.

[0097] According to a twenty-fourth aspect, a glass article is disclosed that includes at least one anti-glare surface prepared by the method of the first aspect having a haze of less than about 25 and a transmittance greater than 90%. The anti-glare surface further includes a Distinctness-of-Image (DOI) 20° of about 80 to about 99.8 and a surface roughness (Ra) of about 5 nm to about 500 nm.

[0098] According to a twenty-fifth aspect, the twenty-fourth aspect is provided, wherein the anti-glare surface is a protective cover glass for a display device.

[0099] According to a twenty-sixth aspect, the twenty-fourth aspect is provided, wherein the haze over the roughened surface varies less than 2%.

[00100] Many variations and modifications may be made to the above-described embodiments of the disclosure without departing substantially from the spirit and various principles of the disclosure. All such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the following claims.

Claims

What is claimed is:

1. A method of making a glass article, comprising: providing a glass substrate comprising a thickness and a primary surface; treating a molten etchant bath by supplying humidified air with a controlled humidity level between 10% and 100% into the molten etchant bath for a predetermined time, thereby providing a treated etchant bath; adding lithium salt to the treated etchant bath providing the treated etchant bath that comprises (by weight):

(a) 20% to about 90% nitrate salt,

(b) 0.1% to 10% silicic acid, and

(c) 0.1% to 25% lithium salt; and submerging the glass substrate in the treated molten etchant bath for an etching duration, wherein the submerging forms a haze over the primary surface of the glass substrate.

2. The method according to claim 1, wherein the treating of the etchant bath by supplying the humidified air is continued through a heating of the treated etchant bath and the submerging of the glass substrate.

3. The method according to claim 1 , wherein the lithium salt is gradually added over the predetermined time.

4. The method according to claim 3, wherein the lithium salt is added in equal proportion at regular intervals over the predetermined time.

5. The method according to claim 1 , wherein the predetermined time for the treating of the etchant bath is a treatment duration of 30 minutes to 24 hours.

6. The method according to claim 1, wherein the predetermined time for the treating of the etchant bath is a treatment duration of 30 minutes to 10 hours.

7. The method according to claim 1, wherein the predetermined time for the treating of the etchant bath is a treatment duration of 1 hour to 4 hours.

8. The method according to claim 1, where in the nitrate salt is from a group consisting of KNOs and NaNOs.

9. The method according to claim 1, wherein the lithium salt is selected from the group consisting of LiOH, Li2O, LiNO₃, I^COs, Li2SO4 and LiCl.

10. The method according to claim 1, wherein the etchant bath further comprises 3% to 10% Na₂CO₃.

11. The method according to claim 1, wherein the etchant bath comprises (by weight):

(a) 60% to about 80% NaNO₃;

(b) 15% to about 35% KNO₃;

(c) 3% to 7% Na₂CO₃;

(d) 0.5% to 4% LiNO₃; and

(e) 0.2% to 1.5% silicic acid.

12. The method according to claim 1, wherein the etchant bath comprises (by weight):

(a) 65% to about 85% KN0₃;

(a) 10% to about 30% NaNO₃;

(c) 3% to 7% Na₂CO₃;

(d) 0.5% to 4% LiNO₃; and

(e) 0.2% to 1.5% silicic acid.

13. The method according to claim 1, wherein the etchant bath is treated by bubbling the humidified air into the etchant bath.

14. The method according to claim 1, wherein the humidity level of the air is from 50% to 100%.

15. The method according to claim 1, further comprising: cooling the glass substrate; and rinsing the glass substrate with deionized water and a citric acid solution.

16. The method according to claim 1, wherein the submerging step is further conducted such that the glass substrate further comprises a compressive stress region that extends from the primary surface to a selected depth, and further wherein the compressive stress region comprises a minimum compressive stress (CS) of 200 MPa and a depth of compression (DOC) from 5 μm to 200 μm.

17. The method according to claim 1, wherein the glass substrate comprises a composition selected from the group consisting of an aluminosilicate glass, a borosilicate glass, a phosphosilicate glass, a soda lime glass, an alkali aluminosilicate glass, and an alkali aluminoborosilicate glass.

18. The method according to claim 1, further comprising: heating an etchant bath to an etching temperature from 350°C to 550°C thereby providing the molten etchant bath.

19. The method according to claim 1, wherein the etching temperature is from 410°C to 490°C.

20. The method according to claim 1, wherein the etching duration is from 10 minutes to 1000 minutes.

21. A display system comprising: the glass substrate having at least one roughened surface prepared by the method of claim 1 including: a haze of less than about 25; and a surface roughness (Ra) of about 5 nm to about 500 nm.

22. The display system according to claim 21, wherein the transmittance is greater than 90%.

23. The display system according to claim 21 , wherein the haze over the roughened surface varies less than 2%.

24. A glass article comprising: at least one anti-glare surface prepared by the method of claim 1 having: a haze of less than about 25%; a transmittance greater than 90% a Distinctness-of-Image (DOI) 20° of about 80 to about 99.8; and a surface roughness (Ra) of about 5 nm to about 500 nm.

25. The glass article of claim 24, wherein the anti -glare surface is a protective cover glass for a display device.

26. The glass article of claim 24, wherein the haze over the roughened surface varies less than 2%.