Foldable electronic device assemblies and cover elements for the same

Abstract

A cover element for a foldable electronic device that includes a foldable glass element, first and second primary surfaces, and a compressive stress region extending from the first primary surface to a first depth that is defined by a stress σ I of at least about 100 MPa in compression at the first primary surface. The device also includes a polymeric layer disposed over the first primary surface. The glass element has a stress profile such that when the glass element is bent to a target bend radius of from 1 mm to 20 mm, to induce a bending stress σ B at the first primary surface in tension, σ I +σ B <400 MPa (in tension). Further, the cover element can withstand a pen drop height of at least 1.5 times that of a control pen drop height of the cover element without the layer according to a Drop Test 1.

What is claimed is: 
     
         1 . An article, comprising:
 a substrate;   a first adhesive layer disposed over a surface of the substrate;   a glass layer disposed over the first adhesive layer, the glass layer comprising a thickness ranging from 25 μm to 200 μm;   a second adhesive layer disposed over the glass layer;   a polymeric layer disposed over and directly contacting the second adhesive layer, the polymeric layer comprising a thickness ranging from 1 μm to 200 μm; and   a coating layer disposed over the polymeric layer.   
     
     
         2 . The article of  claim 1 , further comprising a third adhesive layer disposed over the surface of the substrate and a second polymeric layer disposed over the third adhesive layer,
 wherein the third adhesive layer and the second polymeric layer are disposed between the substrate and the first adhesive layer.   
     
     
         3 . The article of  claim 1 , wherein the polymeric layer comprises a polyimide. 
     
     
         4 . The article of  claim 1 , wherein the glass layer comprises a thickness ranging from 25 μm to 125 μm. 
     
     
         5 . The article of  claim 1 , wherein the polymeric layer comprises a thickness ranging from 10 μm to 100 μm. 
     
     
         6 . The article of  claim 1 , wherein the first adhesive layer comprises a thickness ranging from 1 μm to 100 μm. 
     
     
         7 . The article of  claim 1 , wherein the second adhesive layer comprises a thickness ranging from 1 μm to 100 μm. 
     
     
         8 . The article of  claim 1 , wherein the coating layer comprises a thickness ranging from 1 μm to 100 μm. 
     
     
         9 . The article of  claim 1 , wherein the substrate comprises a display comprising electronic components. 
     
     
         10 . The article of  claim 9 , wherein the surface of the substrate is a user-facing surface of the display. 
     
     
         11 . The article of  claim 1 , wherein the glass layer comprises a compressive stress region that extends from a primary surface of the glass layer to a depth in the glass layer, and wherein the compressive stress region comprises a plurality of ion-exchangeable metal ions and a plurality of ion-exchanged metal ions. 
     
     
         12 . The article of  claim 11 , wherein the second adhesive layer is disposed over and directly contacts the primary surface of the glass layer. 
     
     
         13 . The article of  claim 11 , wherein the compressive stress region comprises a stress (σ I ) of 100 MPa to 2000 MPa in compression at the primary surface of the glass layer, and wherein the second adhesive layer is disposed over and directly contacts the primary surface of the glass layer. 
     
     
         14 . The article of  claim 13 , wherein the glass layer comprises a second primary surface opposite the primary surface,
 wherein the glass layer is characterized by a stress profile such that when the glass layer is bent to a target bend radius of from 1 mm to 20 mm, with a center of curvature on the side of the second primary surface so as to induce a bending stress (σ B ) at the primary surface in tension, and   wherein 0<σ I +σ B <400 MPa (in tension).   
     
     
         15 . The article of  claim 13 , wherein the glass layer comprises a second primary surface opposite the primary surface,
 wherein the glass layer is characterized by a stress profile such that when the glass layer is bent to a target bend radius of from 1 mm to 20 mm, with a center of curvature on the side of the second primary surface so as to induce a bending stress (σ B ) at the primary surface in tension, and   wherein σ I +σ B <0 MPa.   
     
     
         16 . The article of  claim 1 , wherein the glass element has an absence of failure when held at a bend radius of from 1 mm to 5 mm for 60 minutes in an environment of 25° C. and 50% relative humidity. 
     
     
         17 . The article of  claim 1 , wherein the coating layer, as disposed over the polymeric layer, comprises a pencil hardness of 5H or more, measured according to ASTM Test Method D3363 with a load of 750 grams. 
     
     
         18 . A cover glass, comprising:
 a glass layer comprising a thickness ranging from 25 μm to 200 μm;   an adhesive layer disposed over the glass layer;   a polymeric layer disposed over and directly contacting the adhesive layer, the polymeric layer comprising a thickness ranging from 1 μm to 200 μm; and   a coating layer disposed over the polymeric layer.   
     
     
         19 . A foldable electronic device, comprising:
 a display comprising a user-facing surface and electronic components;   an adhesive disposed over a user-facing surface of the display; and   the cover glass of  claim 18  coupled to the user-facing surface of the display via the adhesive.   
     
     
         20 . The foldable electronic device of  claim 19 , wherein the glass layer comprises a thickness ranging from 25 μm to 125 μm.