Textured glass articles and methods of making the same

Abstract

A textured glass article that includes: a glass substrate comprising a thickness, a primary surface and a bulk composition at the midpoint of the thickness; and a textured region defined by the primary surface and comprising a textured region composition. The textured region comprises a sparkle of 2% or less. Further, the bulk composition comprises about 40 mol % to 80 mol % silica and the textured region composition comprises at least about 40 mol % silica.

What is claimed is: 
     
         1 . A method of making a textured glass article, comprising:
 etching an initial primary surface of a glass substrate having a thickness with a hydrofluoric acid-free etchant having a pH of about 3 or less; and   removing the etchant from the glass substrate,   wherein the etching is conducted from above ambient temperature to about 100° C. to form a textured region that is defined by a primary surface of the substrate and comprises a sparkle of 2% or less, and   further wherein the glass substrate comprises a bulk composition at the midpoint of the thickness comprising about 40 mol % to 80 mol % silica and the textured region comprises a textured region composition comprising at least about 40 mol % silica.   
     
     
         2 . The method according to  claim 1 , wherein the textured region composition comprises a higher amount of silica than the silica in the bulk composition. 
     
     
         3 . The method according to  claim 2 , wherein the etching step comprises etching the initial primary surface of the glass substrate having a thickness with a hydrofluoric acid-free etchant having a pH of about 3 or less and an additive salt. 
     
     
         4 . The method according to  claim 3 , wherein the additive salt comprises one or more cations selected from the group consisting of NH 4   + , Al 3+ , Fe 3+ , Ca 2+  and Mg 2+ . 
     
     
         5 . The method according to  claim 3 , wherein the etching step is conducted such that the temperature is from about 90° C. to about 110° C. and the concentration of the additive salt ranges from greater than 0.1M to about 1.5M. 
     
     
         6 . The method according to  claim 2 , further comprising:
 treating the textured region with a second etchant having a pH of about 10.0 or greater to remove the textured region and form a second textured region that comprises a second textured region composition and is defined by a primary surface of the substrate,   wherein the treating is conducted above ambient temperature.   
     
     
         7 . The method according to  claim 6 , wherein the second textured region composition and the bulk composition each comprise a substantially equivalent amount of silica. 
     
     
         8 . A method of making a textured glass article comprising:
 in a first etching step, etching a glass substrate with an etchant comprising a pH of about 3 or less, the etchant being substantially free of hydrofluoric acid; and   after the first etching step, in a second etching step, etching the glass substrate with a second etchant comprising a pH of about 10.0 or greater, thus forming the glass article.   
     
     
         9 . The method of  claim 8 , wherein the etchant comprising the low pH comprises citric acid or HCl. 
     
     
         10 . The method of  claim 9 , wherein
 the etchant comprising the low pH further comprises an additive salt at a concentration from greater than about 0.1M to about 5M, the additive salt comprising an ion selected from the group consisting of: NH 4+ , Al 3′ , Fe 3+ , Ca 2+  and Mg 2+ ; and   the first etching step is conducted from about 15 minutes to about 10 hours.   
     
     
         11 . The method of  claim 8 , wherein the glass substrate has a composition selected from the group consisting of: an aluminosilicate glass; a borosilicate glass; a phosphosilicate glass; a soda lime glass; an alkaline earth boro-aluminosilicate glass; and an alkali-aluminosilicate glass. 
     
     
         12 . The method of  claim 8 , wherein, the glass article comprises a textured region having exposed features with an average feature size of less than about 10 microns. 
     
     
         13 . The method of  claim 8 , wherein, the glass article comprises a textured region having exposed features of less than about 1 micron. 
     
     
         14 . The method of  claim 8 , wherein, the glass article comprises a textured region having a surface roughness (R a ) of from about 10 nm to about 500 nm. 
     
     
         15 . The method of  claim 8 , wherein
 after the first etching step but before the second etching step, the glass substrate comprises a composition, a textured region, and a thickness, wherein the composition of the glass substrate at the textured region comprises a greater percentage of SiO 2  than the composition of the glass substrate at a midpoint of the thickness; and   after the second etching step, the composition of the glass substrate at the textured region and the composition of the glass substrate at the midpoint of the thickness each comprise about a substantially equivalent percentage of SiO 2 .   
     
     
         16 . The method of  claim 8 , wherein, the glass article exhibits a sparkle of 2% or less. 
     
     
         17 . The method of  claim 8  further comprising:
 subjecting the glass article to an ion exchange process that forms a compressive stress region. 
 
     
     
         18 . The method of  claim 8 , wherein the first etching step is conducted at an elevated temperature above ambient temperature. 
     
     
         19 . A textured glass article comprising:
 a glass substrate comprising a thickness, a primary surface, and a bulk composition at a midpoint of the thickness, the bulk composition comprising 40 mol % to 80 mol % silica; and   a textured region bound by the primary surface, the textured region comprising (i) a textured region composition, (ii) a plurality of exposed features at the primary surface having an average maximum dimension of 1 micron or less in a plane defined by the primary surface, each of the plurality of exposed features having a peak and a valley, and the maximum dimension being the greatest distance from one portion of a peak of the exposed feature to another portion of the peak of the exposed feature, and (iii) a surface roughness (R a ) within a range of 0.1 nm to 300 nm,   wherein the textured glass article comprises a sparkle of 2% or less.   
     
     
         20 . The textured glass article of  claim 19 , wherein
 the textured region composition and the bulk composition each comprise about a substantially equivalent percentage of SiO 2 .