Sapphire component with residual compressive stress

Patent metadata

Field	Value
Publication number	US-9623628-B2
Application number	US-201313738200-A
Country	US
Kind code	B2
Filing date	Jan 10, 2013
Priority date	Jan 10, 2013
Publication date	Apr 18, 2017
Grant date	Apr 18, 2017

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.

First claim

I claim:

1. A method comprising:
shaping a sapphire 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 that alters a chemical or physical property of the selected region, the annealing temperature being above 700° C. and below 2030° C.; and
quenching the selected region of the sapphire component below the annealing temperature by introducing a fluid to the selected region that cools the selected region at a higher rate as compared to a non-quenched cooling rate, such that residual compressive stress is generated in the selected region of the sapphire component; wherein:
the selected region of the sapphire component having the generated residual compressive stress comprises a depth less than a thickness of the sapphire component; and
the sapphire component further comprises an untreated region positioned adjacent the selected region on the first major surface 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 sapphire 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 sapphire component forms a cover glass for the electronic device, and the selected region of the sapphire component comprises a corner portion of the 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. The method of claim 12 , wherein the sapphire component further comprises an inner portion positioned between the first and second major surfaces of the sapphire component, the inner portion comprising the substantially single crystal plane orientation.

14. The method of claim 10 further comprising depositing a surface coating over one or both of the first and second major surfaces of the selected region of the sapphire component prior to the laser heating one or both of the first and second major surfaces of the selected region of the sapphire component.

15. The method of claim 14 , wherein the laser heating of one or both of the first and second major surfaces of the selected region further comprises:
removing the deposited surface coating from one or both of the first and second major surfaces of the selected region.

16. The method of claim 1 , wherein the depth of the selected region of the sapphire component is within a range of approximately 1% of the thickness of the sapphire component and 10% of the thickness of the sapphire component.

17. The method of claim 1 , wherein the quenching of the selected region of the sapphire component comprises cooling the selected region of the sapphire component such that the selected region of the sapphire component maintains a substantially single crystal plane orientation.

18. A method comprising:
shaping a sapphire material into a sapphire component for an electronic device, the sapphire component having first and second major surfaces;
heating the sapphire material to an annealing temperature that is within a range of between 700° C. to 2030° C.; and
forming a residual compressive stress in a selected region of the sapphire component by quenching the selected region of the sapphire component using a fluid that cools the selected region below the annealing temperature at an accelerated cooling rate that is greater than an unquenched cooling rate without the fluid, the selected region of the sapphire component having greater residual compressive stress than an untreated region of the sapphire component in which the residual compressive stress is not induced; wherein:
the selected region of the sapphire component comprises a depth less than a thickness of the sapphire component; and
the untreated region of the sapphire component is positioned below the selected region, within the sapphire component.

19. The method of claim 18 , wherein the selected region of the sapphire component comprises an aperture for an audio device.

20. The method of claim 18 , wherein the sapphire component is positioned adjacent a display of the electronic device.

21. The method of claim 20 , wherein the first major surface of the sapphire component is positioned adjacent the display and oriented toward an interior of the electronic device.

22. The method of claim 20 , wherein the second major surface of the sapphire component is positioned opposite the display and oriented toward an exterior of the device.

23. The method of claim 20 , wherein the display is visible through the sapphire component.

24. A method comprising:
heating a selected region of at least one surface of a sapphire component for an electronic device to an annealing temperature that is less than 2030° C. and greater than 700° C., the selected region exhibiting a material toughness distinct from an untreated region of the sapphire component based on the annealing temperature altering a chemical or physical property of the selected region;
quenching the selected region of the sapphire component below the annealing temperature such that a differential cooling rate is generated between the selected region and the untreated region of the sapphire component that is not subject to the quenching; and
creating a residual compressive stress in the selected region of the sapphire component, the generated residual compressive stress created in the selected region of the sapphire component comprises a depth less than a thickness of the sapphire component; wherein
the selected region of the sapphire component is substantially surrounded by the untreated region of the sapphire component.

25. The method of claim 24 , wherein the untreated region of the sapphire component comprises a compressive stress less than the residual compressive stress created in the selected

Assignees

• Apple Inc

Inventors

• Kwong Kelvin

Classifications

• B32B3/266

  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 title

• H04M1/0266

  for a display module assembly · CPC title

• H04M1/185

  Improving the shock resistance of the housing, e.g. by increasing the rigidity · CPC title

• Y10T29/49826

  Assembling or joining · CPC title

• C04B41/0036

  Laser treatment (working by laser beam B23K26/00) · CPC title