Textured region of a substrate to reduce specular reflectance incorporating surface features with an elliptical perimeter or segments thereof, and method of making the same

A substrate for a display article, the substrate comprising:

• a primary surface;
• a base-plane extending through the substrate below the primary surface;
• and
• a textured region at the primary surface, the textured region comprising (i) one or more higher surfaces residing at a higher mean elevation from the base-plane, (ii) one or more lower surfaces residing at a lower mean elevation from the base-plane, (iii) a first portion providing either the one or more higher surfaces or the one or more lower surfaces, and (iv) a second portion providing the other of the one or more higher surfaces and the one or more higher surfaces, whichever the first portion is not providing;
• wherein, elliptical perimeters which lie in planes parallel to the base-plane and reflect a random distribution, define the first portion except for overlapping portions of the elliptical perimeters, where the overlapping portions define in part the second portion.

A method of forming a textured region of a substrate of a display article, the method comprising:

• generating a random distribution of ellipses within an area;
• preparing a lithography mask comprising (a) an area matching the area of the plane;
• (b) material throughout the matching area;
• and (c) voids through the material, wherein the random distribution of the ellipses define either (i) the material throughout the matching area or (ii) the voids through the material;
• exposing a workpiece comprising a substrate, a lithography ink disposed on the substrate, and the lithography mask disposed on the lithography ink, to a curing agent that transmits through the voids through the material of the lithography mask to cure exposed portions of the lithography ink, wherein non-exposed portions of the lithography ink blocked from exposure to the curing agent are not cured and removed along with the lithography mask, and the exposed portions of the lithography ink remain on the substrate as an etching mask;
• and
• contacting the substrate with the etching mask with an etchant, thus forming the textured region.

A method of forming a textured region of a substrate of a display article, the method comprising:

• generating a random distribution of first ellipses within a first area;
• generating a random distribution of second ellipses within a second area, wherein the first ellipses comprise longest dimensions that are on average longer than longest dimensions of the second ellipses on average;
• forming a new area that superimposes the first ellipses of the first area and the second ellipses of the second area, the new area comprising (a) free portions of the first ellipses and the second ellipses that do not overlap;
• (b) overlapping portions of the first ellipses and the second ellipses;
• and (c) empty portions where neither the first ellipses nor the second ellipses are present;
• preparing a lithography mask comprising (a) an area;
• (b) material within the area defined by either (i) the free portions or (ii) a combination of the overlapping portions and the empty portions;
• and (c) voids through the material defined by whichever of (i) the free portions and (ii) the combination of the overlapping portions and the empty portions do not define the material within the area;
• exposing a workpiece comprising a substrate, a lithography ink disposed on the substrate, and the lithography mask disposed on the lithography ink, to a curing agent that transmits through the voids through the material of the lithography mask to cure exposed portions of the lithography ink, wherein non-exposed portions of the lithography ink blocked from exposure to the curing agent are not cured and removed along with the lithography mask, and the exposed portions of the lithography ink remain on the substrate as an etching mask;
• and
• contacting the substrate with the etching mask with an etchant.