Methods and apparatus for improving reliability of cover substrate against impact fractures

Abstract

A substrate having inner and outer major surfaces, a plurality of edge surfaces, and a plurality of corner surfaces; and at least one of: (i) a coating applied over a limited area of the outer major surface of the substrate to produce a composite structure, (ii) an intermediate layer applied to the inner major surface of the substrate, and (iii) an elongate discontinuity disposed at one or more corners of the substrate, each of which operates to reduce catastrophic failures in the substrate resulting from a dynamic sharp impact to the outer major surface of the substrate.

1 . An article, comprising:
 a device body having an outer surface;   a cover substrate having inner and outer major surfaces spaced apart from one another, the inner major surface being disposed toward and covering at least a portion of the outer surface of the device body; and   an intermediate layer disposed between the outer surface of the device body and the cover substrate, where the intermediate layer operates to absorb a majority of kinetic energy produced from a dynamic sharp impact to the outer major surface of the cover substrate and to thereby mitigate damage to the cover substrate and the device body.   
     
     
         2 - 5 . (canceled) 
     
     
         6 . An article, comprising:
 a substrate having inner and outer major surfaces spaced apart from one another, a plurality of edge surfaces spanning between respective peripheral edges of the inner and outer major surfaces, and a plurality of corner surfaces spanning between the respective peripheral edges of the inner and outer major surfaces and between adjacent ones of the edge surfaces; and   a coating applied over a limited area of the outer major surface of the substrate to produce a composite structure, the limited area being less than a total area of the outer major surface, where the coating operates to mitigate damage to the substrate from dynamic sharp impact to the outer major surface, wherein the limited area includes at least one of: at least one edge area spanning between the peripheral edge and a first predetermined distance toward a central region of the outer major surface of the substrate, and   at least one corner area extending adjacent to at least one respective corner surface and spanning between the peripheral edge and a second predetermined distance toward a central region of the outer major surface of the substrate.   
     
     
         7 . The article of  claim 6 , wherein the substrate is formed from one or more of glass, crystalline material, single crystal material, and glass ceramic material. 
     
     
         8 . The article of  claim 6 , wherein the limited area covers no more than about 1 to 20 percent of the total area of the outer major surface. 
     
     
         9 . The article of  claim 6 , wherein a thickness of the coating is between about 10 nanometers to about 1000 micrometers. 
     
     
         10 . The article of  claim 6 , wherein
 the substrate is an ion exchanged glass.   
     
     
         11 . The article of  claim 6 , wherein
 the coating is a transparent and plastically deformable material exhibiting a spring-like response to the dynamic sharp impact to the outer major surface in order to mitigate damage to the substrate, and the coating exhibits a modulus of less than about 50 GPa.   
     
     
         12 . The article of  claim 6 , wherein
 the coating is an ultra-hard material, and the coating exhibits a hardness of at least about 8 GPa.   
     
     
         13 . The article of  claim 6 , wherein the coating includes solid spheres in a binder; and at least one of:
 a volume fraction of the solid spheres is between about 25-75% of a total volume of the solid spheres and the binder;   a mean diameter of the solid spheres is between about 10-1000 um;   and   the solid spheres are formed from one or more of silica ceramic, soda lime glass, barium titanate glass, borosilicate glass, and yttrium stabilized zirconia.   
     
     
         14 . The article of  claim 6 , wherein the coating includes a rough outer surface having a roughness. 
     
     
         15 - 21 . (canceled) 
     
     
         22 . The article of  claim 6 , wherein the limited area covers no more than about 1 to 10 percent of the total area of the outer major surface. 
     
     
         23 . The article of  claim 6 , wherein a thickness of the coating is between about 100 nanometers to about 500 micrometers. 
     
     
         24 . The article of  claim 6 , wherein the substrate is a non-ion exchanged glass. 
     
     
         25 . The article of  claim 6 , wherein the coating comprises one or more of Polymethylmethacrylate (PMMA), Polycarbonate (PC), cycloolefin polymer (COP), cycloolefin copolymer (COC), Polyethylene terephthalate (PET), Polyethylene naphthalate (PEN), Polystyrene, Acrylic, Silicon, Polyurethane elastomer, Polyvinyl Butyral (PVB), Poly Vinyl Chloride (PVC), Thermoplastic Elastomer (TPE), and Styrene Block Copolymer. 
     
     
         26 . The article of  claim 6 , wherein the coating has a modulus in the range from about 1 MPa to about 10 GPa. 
     
     
         27 . The article of  claim 6 , wherein the coating comprises one or more of silicon nitride, silicon oxy-nitride, silicon carbide, silicon oxy-carbide, aluminum nitride, aluminum oxy-nitride (AlON), aluminum carbide, aluminum oxy-carbide, aluminum oxide, diamond-like carbon, nanocrystalline diamond, and indium tin oxide (ITO). 
     
     
         28 . The article of  claim 6 , wherein the coating comprises an oxide.