Glass ceramic substrate and portable electronic device housing using the substrate

Patent metadata

Field	Value
Publication number	US-9718726-B2
Application number	US-201514706406-A
Country	US
Kind code	B2
Filing date	May 7, 2015
Priority date	Nov 7, 2012
Publication date	Aug 1, 2017
Grant date	Aug 1, 2017

Abstract

A glass ceramic substrate includes: an inner layer part having a first thermal expansion coefficient; and a surface layer part having a second thermal expansion coefficient smaller than the first thermal expansion coefficient. The inner layer part contains a first glass matrix and flat alumina particles. The flat alumina particles are dispersed in the glass matrix in a direction in which individual thickness directions are substantially perpendicular to a surface direction of one of main surfaces of the inner layer part. Further, a mean aspect ratio of the flat alumina particles is 3 or more in one of cross sections along the thickness directions of the flat alumina particles out of cross sections of the inner layer part.

First claim

What is claimed is:

1. A glass ceramic substrate, comprising:
an inner layer part having a first thermal expansion coefficient; and
a surface layer part having a second thermal expansion coefficient smaller than the first thermal expansion coefficient,
wherein a crystallinity of the glass ceramic substrate is 25% or less,
the inner layer part contains a first glass matrix having a crystallinity of 25% or less, and flat alumina particles,
the flat alumina particles are dispersed in the glass matrix in a direction in which individual thickness directions are substantially perpendicular to a surface direction of one of main surfaces of the inner layer part, and
a mean aspect ratio of the flat alumina particles is 3 or more in one of cross sections along the thickness directions of the flat alumina particles out of cross sections of the inner layer part.

2. The glass ceramic substrate according to claim 1 ,
wherein in a cross section of the inner layer part, a total cross-sectional area of the flat alumina particles, having a cross section with a thickness of 0.2 μm or more, a maximum diameter of 8 μm or less, and an aspect ratio in a range of 3 to 18 is 20% or more relative to a total area of the cross section of the inner layer part.

3. The glass ceramic substrate according to claim 1 ,
wherein the surface layer part contains a second glass matrix.

4. The glass ceramic substrate according to claim 3 ,
wherein the surface layer part further contains irregular ceramic particles.

5. The glass ceramic substrate according to claim 1 ,
wherein a thickness of the surface layer part is 100 μm or less.

6. The glass ceramic substrate according to claim 1 ,
wherein a glass constituting the first glass matrix is SiO 2 —B 2 O 3 —CaO based glass containing Al 2 O 3 components and, 10% or more of CaO in mole percentage based on oxides when a composition of the glass excluding Al 2 O 3 is 100%.

7. The glass ceramic substrate according to claim 6 ,
wherein in the glass constituting the first glass matrix contains SiO 2 , B 2 O 3 , and CaO by 75% or more in total in mole percentage based on oxides when a composition of the glass excluding Al 2 O 3 is 100%.

8. The glass ceramic substrate according to claim 1 ,
wherein a three-point bending strength of the glass ceramic substrate is 500 MPa or more.

9. A glass ceramic substrate, comprising:
an inner layer part having a first thermal expansion coefficient; and
a surface layer part having a second thermal expansion coefficient smaller than the first thermal expansion coefficient,
wherein a crystallinity of the glass ceramic substrate is 25% or less, and
the inner layer part contains a first glass matrix having a crystallinity of 25% or less, and flat alumina particles having a mean aspect ratio of 3 or more.

10. The glass ceramic substrate according to claim 9 ,
wherein the flat alumina particles have a mean thickness of 0.3 μm or more, a mean major axis of 8 μm or less, and a mean aspect ratio of 3 to 18.

11. The glass ceramic substrate according to claim 9 ,
wherein the surface layer part contains a second glass matrix.

12. The glass ceramic substrate according to claim 11 ,
wherein the surface layer part further contains irregular ceramic particles.

13. The glass ceramic substrate according to claim 9 ,
wherein a thickness of the surface layer part is 100 μm or less.

14. The glass ceramic substrate according to claim 9 ,
wherein a glass constituting the first glass matrix is SiO 2 —B 2 O 3 —CaO based glass containing Al 2 O 3 components and, 10% or more of CaO in mole percentage based on oxides when a composition of the glass excluding Al 2 O 3 is 100%.

15. The glass ceramic substrate according to claim 14 ,
wherein in the glass constituting the first glass matrix contains SiO 2 , B 2 O 3 , and CaO by 75% or more in total in mole percentage based on oxides when a composition of the glass excluding Al 2 O 3 is 100%.

16. The glass ceramic substrate according to claim 9 ,
wherein a three-point bending strength of the glass ceramic substrate is 500 MPa or more.

17. A portable electronic device housing comprising the glass ceramic substrate according to claim 1 .

18. A portable electronic device housing comprising the glass ceramic substrate according to claim 9 .

Assignees

• Asahi Glass Co Ltd

Inventors

• Ohta Seigo
• Tanida Masamichi
• NUMAKURA Hideki
• Li Qing

Classifications

• Y10T428/24174

  including sheet or component perpendicular to plane of web or sheet · CPC title

• Y10T428/131

  Glass, ceramic, or sintered, fused, fired, or calcined metal oxide or metal carbide containing [e.g., porcelain, brick, cement, etc.] · CPC title

• H05K1/0306

  Inorganic insulating substrates, e.g. ceramic, glass · CPC title

• C03C14/004 Primary

  the non-glass component being in the form of particles or flakes · CPC title

• B32B17/06

  comprising glass as the main or only constituent of a layer, next to another layer of a specific {material} · CPC title