SAPPHIRE COMPONENT WITH RESIDUAL COMPRESSIVE STRESS

• US 20140193606A1
• Filed: 01/10/2013
• Published: 07/10/2014
• Est. Priority Date: 01/10/2013
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Kwong, Kelvin
• Granted Patent: US 9,623,628 B2
• Time in Patent Office: Days
• US Class Current: 428/138
• CPC Class Codes: B32B 3/266 characterised by an apertured layer, the apertures going through the whole thickness of the layer, e.g. expanded metal, perforated layer, slit layer regular cells B32B3/12
• CPC Class Codes: C04B 41/0036 Laser treatment working by laser beam B23K26/00
• CPC Class Codes: C04B 41/0081 characterised by the subsequent cooling step
• CPC Class Codes: C30B 29/20 Aluminium oxides
• CPC Class Codes: C30B 33/02 Heat treatment C30B33/04, C30B33/06 take precedence
• CPC Class Codes: H04M 1/0266 for a display module assembly
• CPC Class Codes: H04M 1/185 Improving the rigidity of the casing or resistance to shocks
• CPC Class Codes: Y10T 29/49826 Assembling or joining
• CPC Class Codes: Y10T 428/24331 including nonapertured component
• CPC Class Codes: Y10T 428/24992 Density or compression of components

Abstract

A method comprises shaping an aluminum oxide ceramic material into a component for an electronic device. The component has first and second major surfaces. A selected region of one or both of the first and second major surfaces is heated to an annealing temperature. The selected region is then cooled below the annealing temperature, so that residual compressive stress is generated in the selected region.

Claims

1. A method comprising:

shaping an aluminum oxide ceramic material into a sapphire component for an electronic device, the sapphire component having first and second major surfaces;

heating a selected region of one or both of the first and second major surfaces of the sapphire component to an annealing temperature; and

cooling the selected region of the sapphire component below the annealing temperature, such that residual compressive stress is generated in the selected region of the sapphire component.

2. The method of claim 1, further comprising assembling the sapphire component into the electronic device.

3. The method of claim 1, wherein shaping the aluminum oxide ceramic material comprises forming the sapphire component with a substantially single crystal plane orientation between the first and second major surfaces.

4. The method of claim 3, wherein the selected region of the sapphire component is prone to impact when assembled into the electronic device.

5. The method of claim 4, wherein the selected region of the sapphire component comprises a corner portion of a cover glass, when the sapphire component is assembled into the electronic device.

6. The method of claim 5, wherein the selected region of the sapphire component excludes a central portion of the cover glass, when the sapphire component is assembled into the electronic device.

7. The method of claim 6, wherein the selected region of the sapphire component comprises at least a portion of each of the first and second major surfaces.

8. The method of claim 1, wherein the selected region of the sapphire component excludes one of the first and second major surfaces.

9. The method of claim 1, further comprising defining a failure pattern in the sapphire component, based on the residual compressive stress generated in the selected region.

10. The method of claim 1, wherein heating the selected region of the sapphire component comprises laser heating one or both of the first and second major surfaces, in the selected region.

11. The method of claim 10, wherein cooling the selected region of the sapphire component comprises directing a jet of cooling fluid onto one or both of the first and second major surfaces, in the selected region.

12. The method of claim 11, wherein a substantially single crystal plane orientation is maintained between the first and second major surfaces of the sapphire component, throughout heating and cooling of the selected region.

13. A cover glass component for an electronic device, the cover glass component comprising:

a substantially single crystal aluminum oxide ceramic material having first and second major surfaces, the first and second major surfaces defining the cover glass component therebetween;

a first portion of the cover glass component having a residual compressive stress induced therein; and

a second portion of the cover glass component not having the residual compressive stress induced therein;

wherein the first portion of the cover glass component in which the residual compressive stress is induced has greater residual compressive stress than the second portion of the cover glass component in which the residual compressive stress is not induced.

14. The cover glass component of claim 13, wherein the first portion of the cover glass component is more prone to impact than the second portion, when assembled into the electronic device.

15. The cover glass component of claim 13, wherein the first portion of the cover glass component comprises a corner region of the cover glass component, when assembled into the electronic device.

16. The cover glass component of claim 15, wherein the second portion of the cover glass component comprises a center region of the cover glass component, when assembled into the electronic device.

17. The cover glass component of claim 13, wherein the first portion of the cover glass component is adjacent an edge of the cover glass component and the second portion is spaced from the edge by the first portion.

18. A mobile device comprising a display in combination with the cover glass component of claim 13, wherein the display is visible through the cover glass component.

19. A mobile electronic device comprising:

a display;

a sapphire cover glass component adjacent the display, the sapphire cover glass component having a first major surface adjacent the display, oriented toward an interior of the device, and a second major surface opposite the display, oriented toward an exterior of the device;

wherein a residual compressive stress is induced in a selected region of the sapphire cover glass component, such that the selected region has greater residual compressive stress than another region of the sapphire cover glass component in which the residual compressive stress is not induced.

20. The mobile electronic device of claim 19, wherein the selected region of the sapphire cover glass component comprises a corner portion of one or both of the first and second major surfaces, in which the residual compressive stress is induced.

21. The mobile electronic device of claim 20, wherein the other region of the sapphire glass component comprises a central portion of one or both of the first and second major surfaces, in which the residual compressive stress is not induced.

22. The mobile electronic device of claim 19, wherein the selected region of the sapphire cover glass component in which the residual compressive stress is induced is more prone to impact when the mobile electronic device is dropped, as compared to the other region of the sapphire cover glass component in which the residual compressive stress is not induced.

23. The mobile electronic device of claim 19, wherein the selected region of the cover glass component comprises an aperture for an audio device.