Multi-layered ceramic enclosure

Patent metadata

Field	Value
Publication number	US-9011997-B2
Application number	US-201113246625-A
Country	US
Kind code	B2
Filing date	Sep 27, 2011
Priority date	Sep 27, 2011
Publication date	Apr 21, 2015
Grant date	Apr 21, 2015

Abstract

Techniques for fabricating a laminated ceramic housing that can be used for a handheld computing device that includes an enclosure having structural walls formed from a multi-layered ceramic material that can be radio-transparent. The multi-layered ceramic housing can be formed of a plurality of ceramic materials such as zirconia and alumina in any combination. The multi-layer ceramic substrate includes an inner layer and surface layers that sandwich the inner layer. The multi-layer ceramic substrate has an increased transverse strength due to the surface layers having a coefficient of thermal expansion (CTE) that is less than that of the inner layer.

First claim

What is claimed is:

1. A multi-layer ceramic housing, comprising:
a ceramic laminate structure comprising:
an outer layer defining a substantially continuous exterior surface of the housing;
an inner layer defining an at least partially enclosed internal cavity and a substantially continuous interior surface of the housing; and
a center layer positioned between the outer layer and inner layer;

wherein:
the outer and inner layers have a coefficient of thermal expansion that is less than the center layer;
the first and second outer and inner layers are formed with a higher binder loading than the center layer; and

the first and second layers have a compressive residual stress profile and wherein the center layer has a tensile residual stress profile.

2. The multi-layer ceramic housing as recited in claim 1 , wherein the higher binder loading of the outer and inner layers is a result of a higher density of organic materials infused with the outer and inner layers as compared to the center layer.

3. The multi-layer ceramic housing as recited in claim 1 , wherein the outer and inner layers are formed of a first ceramic material.

4. The multi-layer ceramic housing as recited in claim 3 , wherein the center layer is formed of a second ceramic material.

5. The multi-layer ceramic housing as recited in claim 4 , wherein the first ceramic material is zirconium dioxide.

6. The multi-layer ceramic housing as recited in claim 5 , wherein the second ceramic material is aluminum oxide.

7. The multi-layer ceramic housing as recited in claim 1 , wherein the ceramic laminate structure forms a main body of the multi-layer ceramic housing.

8. The multi-layer ceramic housing as recited in claim 7 , wherein the ceramic laminate structure forms a wall of uniform thickness around the entire main body.

9. The multi-layer ceramic housing as recited in claim 7 , wherein the ceramic laminate structure is thicker at edge or portions of the main body providing additional strength.

10. A structural exterior for use in forming a portable electronic device housing, comprising:
a ceramic inner layer having a first binder loading and
a ceramic first layer in contact with at least a portion of the ceramic inner layer having a second binder loading, wherein the first binder loading and the second binder loading are different; and
wherein:
the structural exterior forms a substantially continuous exterior surface of the housing; and
the structural exterior defines an enclosed internal cavity for receiving components of the portable electronic device.

11. The structural exterior as recited in claim 10 , wherein the ceramic first layer is formed with a higher binder loading than the ceramic inner layer.

12. The structural exterior as recited in claim 10 , wherein the ceramic inner layer is aluminum oxide and the ceramic first layer is zirconium dioxide.

13. The structural exterior as recited in claim 10 , further comprising a ceramic second layer in contact with at least a portion of the ceramic inner layer, the ceramic inner layer being arranged between the first and second ceramic layers in a stacked arrangement.

14. The structural exterior as recited in claim 13 , wherein the higher binder loading of the first and second ceramic layers is a result of a higher density of organic materials infused with the first and second outer layers as compared to the inner layer.

Assignees

• Weber Douglas J
• Apple Inc

Inventors

• Weber Douglas J

Classifications

• C04B2237/62

  Forming laminates or joined articles comprising holes, channels or other types of openings · CPC title

• B32B18/00

  Layered products essentially comprising ceramics, e.g. refractory products · CPC title

• C04B2237/343

  Alumina or aluminates · CPC title

• C04B2235/9607

  Thermal properties, e.g. thermal expansion coefficient · CPC title

• B32B37/144 Primary

  using layers with different mechanical or chemical conditions or properties, e.g. layers with different thermal shrinkage, layers under tension during bonding (constructional features for tensioning B32B38/1825) · CPC title