Bendable glass stack assemblies, articles and methods of making the same
A glass element having a thickness from 25 μm to 125 μm, a first primary surface, a second primary surface, and a compressive stress region extending from the first primary surface to a first depth, the region defined by a compressive stress σI of at least about 100 MPa at the first primary surface. Further, the glass element has a stress profile such that it does not fail when it is subject to 200,000 cycles of bending to a target bend radius of from 1 mm to 20 mm, by the parallel plate method. Still further, the glass element has a puncture resistance of greater than about 1.5 kgf when the first primary surface of the glass element is loaded with a tungsten carbide ball having a diameter of 1.5 mm.
1. A foldable electronic device article, comprising:
an electronic device having a foldable feature, the foldable feature comprising:
a substrate having a thickness from about 25 μm to about 125 μm, the substrate further comprising:
(a) a first primary surface; and
(b) a second primary surface,
wherein the substrate is characterized by:
(a) a pencil hardness of greater than or equal to 8H;
(b) a puncture resistance of greater than about 1.5 kgf when the first primary surface of the substrate is loaded with a tungsten carbide ball having a diameter of 1.5 mm; and one or more of:
(c1) an absence of failure when the substrate is held at a bend radius from about 3 mm to about 10 mm for at least 60 minutes at about 25° C. and about 50 % relative humidity; and
(c2) an absence of failure when the substrate is subject to 200,000 cycles of bending to a target bend radius of from 1 mm to 10 mm, by the parallel plate method.
2. The article of claim 1 , the substrate comprising a plurality of layers.
3. The article of claim 1 , wherein when the first primary surface of the substrate is subject to a 1 kgf load from a Vickers indenter, there is introduced a flaw of ≦100 microns in the first primary surface.
4. The article of claim 1 , wherein the substrate has a Vickers hardness of 550 to 650 kgf/mm 2 .
5. The article of claim 1 , wherein the substrate has a retained B10 bend strength of greater than 800 MPa after contact with a cube corner diamond indenter loaded with 10gf.
6. The article of claim 1 , comprising F/w≦0.076 N/mm, wherein F is the closing force to put the substrate at the target bend radius, and w is the dimension of the substrate in a direction parallel to the axis around which the substrate is bent.
7. The article of claim 1 , wherein the thickness of the substrate is from about 50 μm to about 100 μm.
8. The article of claim 1 , further comprising a coefficient-of-friction-reducing layer disposed on the first primary surface of the substrate.
9. A method of making a stack assembly, comprising the steps:
forming a substrate having a thickness from about 25 μm to about 125 μm, the substrate further comprising:
(a) a first primary surface; and
(b) a second primary surface,
wherein the substrate is characterized by:
(a) a pencil hardness of greater than or equal to 8H; and
(b) a puncture resistance of greater than about 1.5 kgf when the first primary surface of the substrate is loaded with a tungsten carbide ball having a diameter of 1.5 mm; and one or more of:
(c1) an absence of failure when the substrate is held at a bend radius from about 3 mm to about 10 mm for at least 60 minutes at about 25° C. and about 50% relative humidity; and
(c2) an absence of failure when the substrate is subject to 200,000 cycles of bending to a target bend radius of from 1 mm to 10 mm, by the parallel plate method.
10. The method of claim 9 , the substrate comprising a plurality of layers.
11. The method of claim 9 , wherein when the first primary surface of the substrate is subject to a 1 kgf load from a Vickers indenter, there is introduced a flaw of ≦100 microns in the first primary surface.
12. The method of claim 9 , wherein the substrate has a Vickers hardness of 550 to 650 kgf/mm 2 .
13. The method of claim 9 , wherein the substrate has a retained B10 bend strength of greater than 800 MPa after contact with a cube corner diamond indenter loaded with 10gf.
14. The method of claim 9 , comprising F/w≦0.076N/mm, wherein F is the closing force to put the substrate at the target bend radius, and w is the dimension of the substrate in a direction parallel to the axis around which the substrate is bent.