DURABLE GLASS HOUSINGS/ENCLOSURES FOR ELECTRONIC DEVICES

• US 20100047521A1
• Filed: 08/21/2009
• Published: 02/25/2010
• Est. Priority Date: 08/21/2008
• Status: Active Grant

• Current Assignee: Corning Incorporated
• Original Assignee: Corning Incorporated
• Inventors: Pinckney, Linda Ruth, Sabia, Robert, Dejneka, Matthew John, Amin, Jaymin, Rossington, Katherine Rose
• Granted Patent: US 8,187,987 B2
• Time in Patent Office: Days
• US Class Current: 428/141
• CPC Class Codes: C03C 21/002 to perform ion-exchange between alkali ions C03C21/005 takes precedence
• CPC Class Codes: C03C 3/083 containing aluminium oxide or an iron compound
• CPC Class Codes: C03C 3/087 containing calcium oxide, e.g. common sheet or container glass
• CPC Class Codes: C03C 3/091 containing aluminium
• CPC Class Codes: C03C 3/093 containing zinc or zirconium
• CPC Class Codes: Y10T 428/131 Glass, ceramic, or sintered, fused, fired, or calcined metal oxide or metal carbide containing [e.g., porcelain, brick, cement, etc.]
• CPC Class Codes: Y10T 428/24355 Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.]
• CPC Class Codes: Y10T 428/265 1 mil or less

Abstract

The invention relates to glass articles suitable for use as electronic device housing/enclosure or protective cover which comprise a glass material. Particularly, a housing/enclosure/cover comprising an ion-exchanged glass exhibiting the following attributes (1) radio, and microwave frequency transparency, as defined by a loss tangent of less than 0.03 and at a frequency range of between 15 MHz to 3.0 GHz; (2) infrared transparency; (3) a fracture toughness of greater than 0.6 MPa·m^1/2; (4) a 4-point bend strength of greater than 350 MPa; (5) a Vickers hardness of at least 450 kgf/mm² and a Vickers median/radial crack initiation threshold of at least 5 kgf, (6) a Young'"'"'s Modulus ranging between about 50 to 100 GPa; (7) a thermal conductivity of less than 2.0 W/m° C., and (9) and at least one of the following attributes: (i) a compressive surface layer having a depth of layer (DOL) greater and a compressive stress greater than 400 MPa, or, (ii) a central tension of more than 20 MPa.

Claims

1. An article suitable for housing, enclosing or covering the components of a portable electronic device, the article comprising an ion exchanged glass exhibiting radio and microwave frequency transparency, as defined by a loss tangent of less than 0.03 and at a frequency range of between 15 MHz to 3.0 GHz, infrared transparency, a fracture toughness of greater than 0.60 MPa·

m^1/2, a 4-point bend strength of greater than 350 MPa, a Vickers hardness of at least 450 kgf/mm², a Vickers median/radial crack initiation threshold of at least 5 kgf, a Young'"'"'s Modulus ranging between 50 to 100 GPa, a thermal conductivity of less than 2.0 W/m°

C. and at least one of the following attributes;

(i) a compressive surface layer having a depth of layer (DOL) greater than or equal to 20 μ

m and a compressive stress greater than 400 MPa, or,

(ii) a central tension of more than 20 MPa.

2. The article claimed in claim 1 wherein the glass exhibits a refractive index of greater then 1.47@633 nm

3. The article claimed in claim 1 wherein the glass exhibits radio and microwave frequency transparency, as defined by a loss tangent of less than 0.015 at a frequency range of between 500 MHz to 3.0 GHz.

4. The article claimed in claim 1 wherein the glass exhibits a fracture toughness of greater than 0.75 MPa·

m^1/2.

5. The article claimed in claim 1 wherein the glass exhibits a Young'"'"'s Modulus ranging between 50 and 75 GPa.

6. The article claimed in claim 1 wherein the glass exhibits an 4-point bend strength of greater than 475 MPa.

7. The article claimed in claim 1 wherein the glass exhibits a Vickers hardness of at least 500 kgf/mm² and Vickers median/radial crack initiation threshold of greater than 10 kgf.

8. The article claimed in claim 1 wherein the glass exhibits a thermal conductivity of less than 1.5 W/m°

C.

9. The article claimed in claim 1 wherein the glass article is transparent and exhibits at least one surface having a Ra roughness of less than less than 50 nm.

10. The article claimed in claim 1 wherein the glass article appears opaque and exhibits at least one surface having a Ra roughness of between 50 nm and 15 μ

m.

11. The article as claimed in claim 1 wherein the glass exhibits a near-infra-red transparency of greater than 80% at a wavelength ranging from 750 to 2000 nm

12. The article as claimed in claim 1 wherein the article exhibits an overall thickness of 1.2 mm and compressive layer exhibiting a DOL of ranging between 40 to 80 μ

m and the compressive layer exhibits a compressive stress of 525 MPa.

13. The article claimed in claim 1 wherein the glass is an alkali-aluminosilicate glass.

14. The article claimed in claim 13 wherein the alkali-aluminosilicate glass comprises, in mole percent as oxides on a batched basis, of 40-80% SiO₂, 0-28% Al₂O₃, 0-8% B₂O₃, 0-18% Li₂O, 0-10% Na₂O, 0-11% K₂O, 0-16% MgO, 0-18% CaO, 0-15% CaF₂, 0-20% SrO, 0-12% BaO, 0-8% ZnO, 0-4% P₂O₅, 0-8% TiO₂, 0-5% ZrO₂, 0-1% SnO₂ and 0-1 Sb₂O₃, 0-1% As₂O₃

15. The article as claimed in claim 13, wherein the alkali-aluminosilicate glass consists essentially of 64 mol %≦

SiO₂≦

68 mol %;

12 mol %≦

Na₂₀≦

16 mol %;

8 mol %≦

Al₂O₃≦

12 mol %;

0 mol %≦

B₂O₃≦

3 mol %;

2 mol %≦

K₂O≦

5 mol %;

4 mol %≦

MgO≦

6 mol %; and

0 mol %≦

CaO≦

5 mol %, wherein;

66 mol %≦

SiO₂+B₂O₃+CaO≦

69 mol %;

Na₂O+K₂O+B₂O₃+MgO+CaO+SrO>

10 mol %;

5 mol %≦

MgO+CaO+SrO≦

8 mol %;

(Na₂O+B₂O₃)−

Al₂O₃≦

2 mol %;

2 mol %≦

Na₂O−

Al₂O₃≦

6 mol %; and

4 mol %≦

(Na₂O+K₂O)−

Al₂O₃≦

10 mol %.

16. The article as claimed in claim 13, wherein the alkali-aluminosilicate glass comprises, in mole percent as oxides on a batched basis, of:

60-70 mol % SiO₂;

6-14 mol % Al₂O₃;

0-15 mol % B₂O₃;

0-15 mol % Li₂O;

0-20 mol % Na₂O;

0-10 mol % K₂O;

0-8 mol % MgO;

0-10 mol % CaO;

0-5 mol % ZrO₂;

0-1 mol % SnO₂;

0-1 mol % CeO₂;

less than 50 ppm As₂O₃; and

less than 50 ppm Sb₂O₃;

wherein 12 mol %≦

Li₂O+Na₂O+K₂O≦

20 mol % and 0 mol %≦

MgO+CaO≦

10 mol %.

17. The article as claimed in claim 13, wherein the alkali-aluminosilicate glass comprises in mole percent as oxides on a batched basis, of 61-75% SiO₂, 7-15% Al₂O₃, 0-12 B₂O₃, 9-21% Na₂O, 0-4%, 0-7% MgO, and 0-3%.

18. The article as claimed in claim 13, wherein the alkali-aluminosilicate glass comprises in mole percent as oxides on a batched basis, of 60-72% SiO₂;

9-16% Al₂O₃;

5-12% B₂O₃;

8-16% Na₂O; and

0-4% K₂O, wherein

$\frac{{\mathrm{Al}}_2<br><br>O_3<br><br>\left(\mathrm{mol}<br><br><br><br>\%\right)+B_2<br><br>O_3<br><br>\left(\mathrm{mol}<br><br><br><br>\%\right)}{\sum <br><br>\mathrm{alkali}<br><br><br><br>\mathrm{metal}<br><br><br><br>\mathrm{modifiers}<br><br><br><br>\left(\mathrm{mol}<br><br><br><br>\%\right)}><br><br>1$

19. The article as claimed in claim 15 wherein the glass exhibits a liquidus viscosity of greater than 130,000 poise at temperatures below 1275°

C.

20. The article as claimed in claim 15 wherein the glass is fusion formable and the article is formed by standard processing techniques selected from the group consisting of pressing, sagging, vacuum sagging, sheet coin and combinations thereof.