Thin safety glass having improved mechanical characteristics

Patent metadata

Field	Value
Publication number	US-10077204-B2
Application number	US-201514814335-A
Country	US
Kind code	B2
Filing date	Jul 30, 2015
Priority date	Jul 31, 2014
Publication date	Sep 18, 2018
Grant date	Sep 18, 2018

Abstract

A strengthened glass sheet product along with a process and an apparatus for strengthening a glass sheet are provided. The process comprises cooling the glass sheet by non-contact thermal conduction for sufficiently long to fix a surface compression and central tension of the sheet. The process results in thermally strengthened glass sheets having improved breakage properties.

First claim

What is claimed is:

1. A thermally strengthened glass sheet:
the glass sheet having a thickness, expressed in millimeters, of t, a length, expressed in millimeters, of l, and a width, expressed in millimeters, of w, t being less than l and less than w;
the glass sheet comprising a glass having a low temperature linear CTE, expressed in 1/° C., of α S CTE , a high temperature linear CTE, expressed in 1/° C., of α L CTE , an elastic modulus, expressed in GPa, of E, a strain temperature, expressed in units of ° C., of T strain , and a softening temperature, expressed in units of ° C., of T soft ;
the glass sheet having a thermally induced central tension of less than 300 MPa and greater than

P

1
⁢
CT

⁡

(

h
CT

)

*
t

2
⁢

(

2
⁢

P

2
⁢
CT

⁡

(

h
CT

)

+
t

)

·
E
·

[

T
strain

·

α
CTE
s

+

α
CTE
L

·

(

T
soft

-

T
strain

)

]

;

in units of MPa;
wherein P 1CT is given by

910.2
-

259.2
·

exp
⁡

(

-

h
CT

0.143

)

;

P 2CT is given by

2.53
+

23.65

(

1
+

(

h
CT

0.00738

)

1.58

)

;

and wherein h CT is a constant greater than or equal to 0.020, wherein the first major surface has a roughness in the range of from 0.2 to 0.4 nm Ra over an area of 10 μm×10 μm.

2. The glass sheet according to claim 1 wherein h CT is greater than or equal to 0.022.

3. The glass sheet according to claim 1 wherein h CT is greater than or equal to 0.024.

4. The glass sheet according to claim 1 wherein h CT is greater than or equal to 0.026.

5. The glass sheet according to claim 1 wherein h CT is greater than or equal to 0.028.

6. The glass sheet according to claim 1 wherein h CT is greater than or equal to 0.030.

7. The glass sheet according to claim 1 wherein h CT is greater than or equal to 0.0625.

8. The glass sheet according to claim 1 wherein h CT is greater than or equal to 0.065.

9. The glass sheet according to claim 1 wherein the first surface of the sheet is flat to 50 μm total indicator run-out (TIR) along any 50 mm or less profile of the first major surface.

10. The glass sheet according to claim 1 wherein the first major surface has a roughness in the range of from 0.2 to 0.3 nm Ra over an area of 10 μm×10 μm.

11. The glass sheet according to claim 1 wherein the first major surface has a coating.

12. The glass sheet according to claim 1 , l and w each being at least 10 mm.

13. The glass sheet according to claim 1 , l and w each being at least 40 mm.

14. The glass sheet according to claim 1 , wherein the ratio l/t and the ratio w/t each are equal to 10/1 or more.

15. The glass sheet according to claim 13 , wherein the ratio l/t and the ratio w/t each are equal to 20/1 or more.

16. The glass sheet according to claim 1 , wherein the ratio l/t and the ratio w/t each are equal to 100/1 or more.

17. The glass sheet according to claim 1 wherein t is 6 mm or less.

18. The glass sheet according to claim 1 wherein t is 3 mm or less.

19. The glass sheet according to claim 1 wherein t is less than 2 mm.

20. The glass sheet according to claim 1 wherein t is 1 mm or less.

21. The glass sheet according to claim 15 wherein t is 0.7 mm or less.

22. The glass sheet according to claim 1 wherein t is 0.5 mm or less.

23. The glass sheet accordi

Assignees

• Corning Inc

Inventors

• Maschmeyer Richard Orr
• Thomas John Christopher
• Wasson Kevin Lee

Classifications

• B60J1/001

  Double glazing for vehicles · CPC title

• B32B17/10036

  comprising two outer glass sheets · CPC title

• C03B29/12

  being in a horizontal position on a fluid support, e.g. a gas or molten metal · CPC title

• C03B27/044

  for flat or bent glass sheets being in a horizontal position · CPC title

• C03B29/16

  Glass sheets · CPC title