Scratch and damage resistant laminated glass articles
Scratch and damage resistant laminated glass articles are disclosed. According to one aspect, a laminated glass article may include a glass core layer formed from core glass composition and includes a core glass elastic modulus E C and at least one glass clad layer fused directly to the glass core layer. The at least one glass clad layer may be formed from an ion exchangeable clad glass composition different than the core glass composition and includes a clad glass elastic modulus E CL . The laminated glass article may have a total thickness T and the at least one glass clad layer may have a thickness T CL that is greater than or equal to 30% of the total thickness T. E C may be at least 5% greater than E CL .
1. A laminated glass article comprising:
a glass core layer formed from an alkali-aluminosilicate core glass composition and comprising a core glass elastic modulus E C ; and
at least one glass clad layer fused directly to the glass core layer, the at least one glass clad layer formed from an ion exchangeable, alkali-aluminosilicate clad glass composition different than the alkali-aluminosilicate core glass composition, the at least one glass clad layer comprising a clad glass elastic modulus E CL , wherein:
the laminated glass article has a total thickness T and the at least one glass clad layer has a thickness T CL that is greater than or equal to 30% of the total thickness T;
E C is at least 5% greater than E CL ; and
E C is greater than 76.5 GPa and less than or equal to 90 GPa.
2. The laminated glass article of claim 1 , wherein E CL is less than or equal to 76.5 GPa.
3. The laminated glass article of claim 2 , wherein E CL is greater than or equal to 60 GPa.
4. The laminated glass article of claim 1 , wherein a difference between E C and E CL is greater than or equal to 5 GPa.
5. The laminated glass article of claim 1 , wherein the thickness T CL of the at least one glass clad layer is greater than or equal to 35% of the total thickness T.
6. The laminated glass article of claim 1 , wherein a core refractive index n C of the glass core layer is greater than a clad refractive index n CL of the at least one glass clad layer.
7. The laminated glass article of claim 6 , wherein the clad refractive index n CL is greater than or equal to 1.45 and less than or equal to 1.55.
8. The laminated glass article of claim 1 , wherein the at least one glass clad layer comprises a first glass clad layer and a second glass clad layer, wherein:
the first glass clad layer is fused directly to a first surface of the glass core layer; and
the second glass clad layer is fused directly to a second surface of the glass core layer opposite the first surface of the glass core layer.
9. The laminated glass article of claim 1 , wherein:
the glass core layer has a core coefficient of thermal expansion CTE C from 20° C. temperature to 300° C.;
the at least one glass clad layer has a clad coefficient of thermal expansion CTE CL from 20° C. to 300° C.; and
CTE C is greater than or equal to CTE CL .
10. The laminated glass article of claim 9 , wherein a surface compressive stress in the laminated glass article due to a difference between CTE C and CTE CL is greater than or equal to 10 MPa and less than or equal to 100 MPa.
11. The laminated glass article of claim 10 , wherein the laminated glass article has a depth of compression due to the difference between CTE C and CTE CL that is greater than or equal to 20% of the total thickness T.
12. The laminated glass article of claim 1 , wherein the glass core layer is formed from an ion exchangeable core glass composition.
13. The laminated glass article of claim 12 , wherein:
the glass core layer is exposed at an edge of the laminated glass article; and
the glass core layer comprises a surface compressive stress and depth of compression at the edge of the laminated glass article.
14. The laminated glass article of claim 1 , wherein the laminated glass article is ion exchange strengthened such that the laminated glass article comprises a compressive stress region due to ion exchange extending from a surface of the at least one glass clad layer and into the total thickness T of the laminated glass article to a depth of compression DOC.
15. The laminated glass article of claim 14 , wherein:
the laminated glass article has a surface compressive stress CS 0 due to ion exchange at the surface of the at least one glass clad layer; and
the depth of compression DOC due to ion exchange is less than or equal to 30% of the thickness T CL of the at least one glass clad layer.
16. The laminated glass article of claim 14 , wherein:
the glass core layer has a core coefficient of thermal expansion CTE C from 20° C. to 300° C.;
the at least one glass clad layer has a clad coefficient of thermal expansion CTE CL from 20° C. to 300° C.; and
CTE C is greater than or equal to CTE CL .
17. The laminated glass article of claim 14 , wherein a concentration of Na 2 O in the at least one glass clad layer decreases from a surface of the at least one glass clad layer, is a minimum at an intermediate point within a thickness of the at least one glass clad layer, and increases from the intermediate point to an interface layer between the at least one glass clad layer and the glass core layer.
18. The laminated glass article of claim 14 , wherein a weight gain due to ion exchange strengthening is less than 0.5%.
19. The laminated glass article of claim 14 , wherein the laminated glass article has a Knoop scratch initiation threshold greater than or equal to 2 N and less than or equal to 8 N.
20. The laminated glass article of claim 1 , comprising a surface dynamic strength greater than or equal to 400 N.
21. The laminated glass article of claim 1 , comprising an edge dynamic strength greater than or equal to 200 N.
22. A laminated glass article comprising:
a glass core layer formed from an ion exchangeable, alkali-aluminosilicate core glass composition and comprising a core refractive index n C and a core coefficient of thermal expansion CTE C from 20° C. temperature to 300° C.; and
at least one glass clad layer fused directly to the glass core layer, the at least one glass clad layer formed from an ion exchangeable, alkali-aluminosilicate clad glass composition different than the ion exchangeable, alkali-aluminosilicate core glass composition, the at least one glass clad layer comprising a clad refractive index n CL and a clad coefficient of thermal expansion CTE CL from 20° C. to 300° C., wherein:
the laminated glass article has a total thickness T and the at least one glass clad layer has a thickness T CL that is greater than or equal to 30% of the total thickness T;
the core refractive index n C is greater than or equal to 1.506 and less than or equal to 1.55;
the core refractive index n C of the glass core layer is greater than the clad refractive index n CL of the at least one glass clad layer; and
CTE C is greater than or equal to CTE CL .
23. The laminated glass article of claim 22 , wherein the clad refractive index n CL is greater than or equal to 1.45 and less than or equal to 1.55.
24. The laminated glass article of claim 22 , wherein a surface compressive stress in the laminated glass article due to a difference between CTE C and CTE CL is greater than or equal to 10 MPa and less than or equal to 100 MPa.
25. The laminated glass article of claim 24 , wherein the laminated glass article has a depth of compression due to the difference between CTE C and CTE CL that is greater than or equal to 20% of the total thickness T.
26. The laminated glass article of claim 22 , wherein the laminated glass article has a Knoop scratch initiation threshold greater than or equal to 2 N and less than or equal to 8 N.
27. The laminated glass article of claim 22 , wherein:
the laminated glass article is ion exchange strengthened;
a surface compressive stress CS 0 due to ion exchange at a surface of the at least one glass clad layer is greater than or equal to 200 MPa; and
a depth of compression DOC due to ion exchange is less than or equal to 20% of the thickness T CL of the at least one glass clad layer.
28. The laminated glass article of claim 22 , comprising a surface dynamic strength greater than or equal to 400 N.
29. The laminated glass article of claim 22 , comprising an edge dynamic strength greater than or equal to 200 N.