A substrate for a display article is described herein including (a) a primary surface; and (b) a textured region disposed at the primary surface, the textured region comprising: (i) one or more higher surfaces residing at a higher mean elevation parallel to a base-plane disposed below the textured region extending through the substrate; (ii) one or more lower surfaces residing at a lower mean elevation parallel to the base-plane; and (iii) surface features providing at a least a portion of either or both of (i) the one or more higher surfaces and (ii) the one or more lower surfaces. The surface features can include larger surface features and smaller surface features, either or both providing one or more surfaces of the substrate that reside at one or more intermediate mean elevations parallel to the base-plane between the higher mean elevation and the lower mean elevation.

A glass substrate with modified surface regions is disclosed. The glass substrate includes an alkali-containing bulk, a first alkali-depleted region, a second alkali-depleted region, and a first ion-exchanged region. The alkali-containing bulk has a first surface and a second surface with the first and second surfaces on opposite sides. The first alkali-depleted region extends into the alkali-containing bulk from the first surface. The second alkali-depleted region extends into the alkali-containing bulk from the second surface. The first ion-exchanged region extends into the alkali-containing bulk from the first surface. The first alkali-depleted region, the second alkali-depleted region, and the first ion-exchanged region each have a substantially homogenous composition. A method of forming the glass substrate is disclosed. The method includes simultaneously forming the first alkali-depleted region and the first ion-exchanged region in the first surface. The method also includes near-simultaneously forming the second alkali-depleted region in the second surface.

A glass of the present invention includes as a glass composition, in terms of mass %, 50% to 75% of SiO.sub.2, 1% to 30% of Al.sub.2O.sub.3, 0% to 25% of B.sub.2O.sub.3, 0% to 10% of Li.sub.2O, 0.01% to 20% of Na.sub.2O, 0% to 10% of K.sub.2O, 0.0001% to 0.1% of Fe.sub.2O.sub.3, 0.00001% to 0.01% of Cr, 0.00001% to 0.01% of Ni, and 0.0001% to 0.5% of TiO.sub.2.

A glass of the present invention includes as a glass composition, in terms of mass %, 50% to 75% of SiO.sub.2, 1% to 30% of Al.sub.2O.sub.3, 0% to 25% of B.sub.2O.sub.3, 0% to 10% of Li.sub.2O, 0.01% to 20% of Na.sub.2O, 0% to 10% of K.sub.2O, 0.0001% to 0.1% of Fe.sub.2O.sub.3, 0.00001% to 0.01% of Cr, 0.00001% to 0.01% of Ni, and 0.0001% to 0.5% of TiO.sub.2.

Methods of characterizing ion-exchanged chemically strengthened glass containing lithium are disclosed. The methods allow for performing quality control of the stress profile in chemically strengthened Li-containing glasses having a surface stress spike produced in a potassium-containing salt, especially in a salt having both potassium and sodium. The method allows the measurement of the surface compression and the depth of the spike, and its contribution to the center tension, as well as the compression at the bottom of the spike, and the total center tension and calculation of the stress at the knee where the spike and the deep region of the stress profile intersect. The measurements are for a commercially important profile that is near-parabolic in shape in most of the interior of the substrate apart from the spike.

Strengthened glass-based substrates having a first outer region compressive stress and a first side having first coating thereon are disclosed. The first coating comprising a material selected to have a first coating Young's modulus value, a first coating thickness, and a first coating stress that is either neutral or compressive, such that the absolute value of first outer region compressive stress is greater than the absolute value of the first coating stress. Methods of making glass-based articles are provided, and glass-based articles having coatings that provide different strength values and/or reliability on different sides of the glass-based articles are also disclosed.

A patterned article that includes: an alkali silicate glass substrate comprising a thickness and a primary surface, the substrate having a bulk composition; a patterned region defined by at least a portion of the primary surface; and a compressive stress region that extends from the at least a portion of the primary surface to a first depth within the substrate. The patterned region comprises a surface roughness (Ra) from about 1 nm to about 600 nm and at least one of a plurality of protrusions and a plurality of depressions. Further, each of the compressive stress region and the patterned region comprises a concentration of at least one alkali metal ion that is different than the concentration of the at least one alkali metal ion in the bulk composition.

Methods of improving the measurement of knee stress in an ion-exchanged chemically strengthened Li-containing glass sample that includes a knee are disclosed. One of the methods includes compensating for a shift in the location of the TIR-PR transition location associated with the critical angle location, wherein the shift is due to the presence of a leaky mode. Another method includes applying select criteria to the captured mode spectra image to ensure a high-quality image is used for the knee stress calculation. Another method combines direct and indirect measurements of the knee stress using the mode spectra from multiple samples to obtain greater accuracy and precision as compared to using either the direct measurement method or the indirect measurement method alone. Quality control methods of forming the glass samples using measured mode spectra and related techniques for ensuring an accurate measurement of the knee stress are also disclosed.

Differentially strengthened cover members for electronic devices are disclosed. The differentially strengthened cover members include at least one chemically strengthened zone that improves the resistance of the cover member to cracking. One or more of the chemically strengthened zones may cover or at least partially surround a portion of the cover member to be protected from damage.

Methods of characterizing ion-exchanged chemically strengthened Li-containing glasses include: a) measuring a mode spectrum of the glass sample; b) using the mode spectrum, estimating a first contribution to the center tension associated with a spike region and estimating a second contribution to the center tension due to a deep region only, wherein the deep region is assumed to follow a power-law stress profile; and c) determining a total center tension by adding of the first and second contributions to the center tension. The methods can be used for quality control during manufacturing of glass samples by comparing the total center tension to a center tension specification that provides optimum strength and durability.