Foldable cover and display for an electronic device

1. An electronic device comprising:

a display;

a front cover positioned over the display and including a first chemically strengthened glass layer defining a front foldable region that defines a first fold in a folded configuration of the electronic device, the first fold having a first minimum bend radius; and

a rear cover including a second chemically strengthened glass layer defining a rear foldable region that defines a second fold in the folded configuration of the electronic device, the second fold having a second minimum bend radius that is greater than the first minimum bend radius, wherein:

the front cover defines a front surface of the electronic device in an unfolded configuration of the electronic device; and

the rear cover defines a rear surface of the electronic device in the unfolded configuration of the electronic device.

2. The electronic device of claim 1 , wherein, in the unfolded configuration of the electronic device, a magnitude of a compressive stress at an exterior surface of the rear foldable region is greater than a magnitude of a compressive stress at an interior surface of the rear foldable region.

3. The electronic device of claim 2 , wherein the compressive stress at the exterior surface of the rear foldable region is partly due to bending induced compressive stress.

4. The electronic device of claim 2 , wherein the second chemically strengthened glass layer has a thickness that is greater than a thickness of the first chemically strengthened glass layer.

5. The electronic device of claim 1 , wherein:

the display is a first display;

the electronic device further comprises a second display; and

the rear cover is positioned over the second display.

6. The electronic device of claim 1 , further comprising a housing coupled to the front cover and the rear cover and configured to move between the unfolded configuration and the folded configuration.

7. The electronic device of claim 1 , wherein each of the first chemically strengthened glass layer and the second chemically strengthened glass layer is formed of an aluminosilicate glass.

8. An electronic device comprising:

a first cover including a first cover layer formed from a glass material and defining a first foldable portion, the first cover layer defining a first fold in a folded configuration of the electronic device and comprising:

an exterior surface that defines an inside of the first fold;

an interior surface that defines an outside of the first fold; and

a compressive stress layer extending along each of the exterior surface and the interior surface of the first cover layer;

a second cover including a second cover layer and defining a second foldable portion, the second cover layer defining a second fold in the folded configuration of the electronic device and comprising:

an exterior surface that defines an outside of the second fold; and

an interior surface that defines an inside of the second fold;

a housing positioned between and coupled to the first cover and the second cover; and

a flexible display positioned at least partially within the housing and viewable through the first cover.

9. The electronic device of claim 8 , wherein:

the first fold defines a first outside bend radius at the interior surface of the first cover layer; and

the second fold defines a second outside bend radius, greater than the first outside bend radius, at the exterior surface of the second cover layer.

10. The electronic device of claim 9 , wherein, in an unfolded configuration of the electronic device and in the first foldable portion, a magnitude of a compressive stress at the interior surface of the first cover layer is greater than a magnitude of a compressive stress at the exterior surface of the first cover layer.

11. The electronic device of claim 10 , wherein, in the unfolded configuration of the electronic device and in the first foldable portion, the interior surface of the first cover layer has a first bending-induced compressive stress.

12. The electronic device of claim 11 , wherein:

the glass material is a first glass material;

the second cover layer is formed from a second glass material; and

in the unfolded configuration of the electronic device and in the second foldable portion, the exterior surface of the second cover layer has a second bending-induced compressive stress.

13. The electronic device of claim 8 , wherein the second foldable portion has a uniform thickness.

14. The electronic device of claim 8 , wherein the second cover is translucent.

15. An electronic device comprising:

a first cover comprising a first chemically strengthened cover layer formed from a first glass material and defining:

a first foldable region that defines a first fold in a folded configuration of the electronic device; and

an exterior surface that defines an inside of the first fold;

a second cover comprising a second chemically strengthened cover layer formed from a second glass material and defining:

a second foldable region that defines a second fold in the folded configuration of the electronic device; and

an exterior surface that defines an outside of the second fold; and

a display positioned below and viewable through the first cover.

16. The electronic device of claim 15 , wherein the second chemically strengthened cover layer comprises:

an exterior ion-exchanged layer extending along the exterior surface in the second foldable region; and

an interior ion-exchanged layer extending along an interior surface in the second foldable region.

17. The electronic device of claim 16 , wherein:

a depth of the exterior ion-exchanged layer is equal to a depth of the interior ion-exchanged layer; and

in an unfolded configuration of the electronic device, a magnitude of a compressive stress at the exterior surface in the second foldable region is greater than a magnitude of a compressive stress at the interior surface of the second foldable region.

18. The electronic device of claim 16 , wherein:

the electronic device has an intermediate configuration between an unfolded configuration and the folded configuration; and

a magnitude of a bending-induced stress at the exterior surface of the second foldable region in the unfolded configuration is greater than a magnitude of a bending-induced stress at the exterior surface of the second foldable region in the intermediate configuration.

19. The electronic device of claim 15 , further comprising a housing and a flexible battery positioned within the housing.

20. The electronic device of claim 15 , wherein the second chemically strengthened cover layer is transparent.