Sapphire and glass laminates with a gradient layer

• US 10,639,867 B2
• Filed: 09/21/2017
• Issued: 05/05/2020
• Est. Priority Date: 09/23/2016
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Nguyen, Que Anh S., Memering, Dale N., Jones, Christopher D., Rogers, Matthew
• Primary Examiner(s): Rummel, Ian A
• Application Number:
  US15/711,851
• Publication Number:
  US 20180086026A1
• Time in Patent Office: 957 Days
• CPC Class Codes: B32B 15/20 comprising aluminium or copper B32B15/016 and B32B15/017 take precedence
• CPC Class Codes: B32B 17/06 comprising glass as the main or only constituent of a layer, next to another layer of a specific material
• CPC Class Codes: B32B 2250/02 2 layers
• CPC Class Codes: B32B 2255/20 Inorganic coating
• CPC Class Codes: B32B 2307/412 Transparent
• CPC Class Codes: B32B 2307/584 Scratch resistance
• CPC Class Codes: B32B 2307/704 Crystalline
• CPC Class Codes: B32B 2307/732 Dimensional properties
• CPC Class Codes: B32B 2457/208 Touch screens
• CPC Class Codes: B32B 2571/00 Protective equipment
• CPC Class Codes: B32B 5/145 Variation across the thickness of the layer
• CPC Class Codes: B32B 7/022 Mechanical properties
• CPC Class Codes: B32B 7/10 at least one layer having inter-reactive properties
• CPC Class Codes: B32B 9/005 comprising one layer of ceramic material, e.g. porcelain, ceramic tile layered products with at least two ceramic layers composed mainly of ceramic B32B18/00
• CPC Class Codes: B32B 9/04 comprising such particular substance as the main or only constituent of a layer, which is next to another layer of the same or of a different material next to a glass layer B32B17/06; layered products with at least two ceramic layers composed mainly of ceramic B32B18/00
• CPC Class Codes: C03C 3/125 containing aluminium as glass former
• CPC Class Codes: C30B 29/20 Aluminium oxides
• CPC Class Codes: G06F 3/0488 using a touch-screen or digitiser, e.g. input of commands through traced gestures

Abstract

A sapphire sheet is laminated to a glass sheet with a gradient layer that transitions from a composition of predominantly Al₂O₃ at the sapphire sheet to a composition of predominantly SiO₂ at the glass sheet. The gradient layer chemically bonds to both the sapphire sheet and the glass sheet and has no distinct interfaces.

Claims

1. An electronic device including a transparent cover glass, the electronic device comprising:

a housing;

a display positioned within the housing;

a cover glass disposed over the display and attached to the housing, the cover glass comprising;

a sapphire sheet;

a glass sheet; and

a gradient layer disposed between the sapphire sheet and the glass sheet and that transitions from a composition that is predominantly Al₂O₃ at the sapphire sheet to a composition that is predominantly SiO₂ at the glass sheet, and wherein the gradient layer includes a first region including nanocrystalline Al₂O₃ positioned proximate the sapphire sheet and a second region including amorphous Al₂O₃ positioned between the nanocrystalline Al₂O₃ and the glass sheet.

2. The electronic device of claim 1 wherein the gradient layer gradually transitions from a composition that is predominantly Al₂O₃ at the sapphire sheet to a composition that is predominantly SiO₂ at the glass sheet.

3. The electronic device of claim 1 wherein the gradient layer is between 25 and 300 nanometers thick.

4. A glass and sapphire laminate comprising:

a sapphire sheet;

a glass sheet; and

a gradient layer disposed between the sapphire sheet and the glass sheet and that transitions from a composition that is predominantly Al₂O₃ at the sapphire sheet to a composition that is predominantly SiO₂ at the glass sheet, and wherein the gradient layer includes a first region including nanocrystalline Al₂O₃ positioned proximate the sapphire sheet and a second region including amorphous Al₂O₃ positioned between the nanocrystalline Al₂O₃ and the glass sheet.

5. The laminate of claim 4 wherein the Al₂O₃ nanocrystals have a crystalline orientation that matches a crystalline orientation of the sapphire sheet.

6. The laminate of claim 4 wherein the Al₂O₃ nanocrystals have a crystalline orientation that is different from a crystalline orientation of the sapphire sheet.

7. The laminate of claim 4 wherein when moving in a direction away from the sapphire sheet, the gradient layer transitions from the layer of Al₂O₃ nanocrystals to a mixture of Al₂O₃ nanocrystals and amorphous Al₂O₃.

8. The laminate of claim 7 wherein when moving in a direction away from the sapphire sheet, the gradient layer transitions from the mixture of Al₂O₃ nanocrystals and amorphous Al₂O₃ to predominantly amorphous SiO₂.

9. The laminate of claim 4 wherein the gradient layer gradually changes in chemical composition from predominantly Al₂O₃ to predominantly SiO₂.

10. The laminate of claim 4 wherein the gradient layer is between 25 and 300 nanometers thick.

11. The laminate of claim 4 wherein the sapphire sheet is between 5 and 100 microns thick.

12. The laminate of claim 4 wherein the glass sheet is between 100 and 1000 microns thick.

13. The laminate of claim 4 wherein the gradient layer is a first gradient layer and the laminate further comprises a second gradient layer that is disposed on the sapphire sheet on a side opposite of the first gradient layer.

14. A method of bonding a sapphire sheet to a glass sheet, the method comprising:

depositing a gradient layer on a first surface of the sapphire sheet, wherein the gradient layer is predominantly composed of Al₂O₃ at the sapphire sheet and transitions to predominantly SiO₂ at an outer surface of the gradient layer;

annealing the sapphire sheet and the gradient layer at a temperature sufficient to chemically bond the gradient layer to the sapphire sheet;

disposing a glass sheet on the outer surface of the gradient layer; and

annealing the glass sheet, the gradient layer and the sapphire sheet at a temperature sufficient to chemically bond the glass sheet to the gradient layer, and

wherein the gradient layer includes a first region including nanocrystalline Al₂O₃ positioned proximate the sapphire sheet and a second region including amorphous Al₂O₃ positioned between the nanocrystalline Al₂O₃ and the glass sheet.

15. The method of claim 14 wherein the gradient layer is deposited as an amorphous layer having a substantially linear gradient that varies from predominantly Al₂O₃ at the sapphire sheet to predominantly SiO₂ at an outer surface of the gradient layer.

16. The method of claim 14 wherein the sapphire sheet is annealed at a temperature above a softening point of the glass sheet.

17. The method of claim 14 wherein annealing the sapphire sheet and the gradient layer causes a layer of Al₂O₃ nanocrystals to form at an interface between the gradient layer and the sapphire sheet.

18. The method of claim 14 wherein the gradient layer is also deposited on a second surface of the sapphire sheet that is opposite the first surface.