Glass-ceramic articles having specified elastic modulus and fracture toughness

Patent metadata

Field	Value
Publication number	US-11927722-B2
Application number	US-202318120488-A
Country	US
Kind code	B2
Filing date	Mar 13, 2023
Priority date	Apr 1, 2021
Publication date	Mar 12, 2024
Grant date	Mar 12, 2024

Abstract

A transparent article is described herein that includes: a glass-ceramic substrate comprising first and second primary surfaces opposing one another and a crystallinity of at least 40% by weight; and an optical film structure disposed on the first primary surface. The optical film structure comprises a plurality of alternating high refractive index (RI) and low RI layers and a scratch-resistant layer. The article also exhibits an average photopic transmittance of greater than 80% and a maximum hardness of greater than 10 GPa, as measured by a Berkovich Hardness Test over an indentation depth range from about 100 nm to about 500 nm. The glass-ceramic substrate comprises an elastic modulus of greater than 85 GPa and a fracture toughness of greater than 0.8 MPa·√m. Further, the optical film structure exhibits a residual compressive stress of ≥700 MPa and an elastic modulus of ≥140 GPa.

First claim

What is claimed is:

1. An article, comprising:
a glass-ceramic substrate comprising a first primary surface and a second primary surface, the first primary surface and the second primary surface opposing one another; and
an optical film structure defining an outer surface, the optical film structure disposed on the first primary surface,
wherein the glass-ceramic substrate comprises an elastic modulus of greater than 85 GPa and a fracture toughness of greater than 0.8 MPa·√m,
wherein:
the article exhibits a maximum hardness of greater than 10 GPa, as measured by a Berkovich Hardness Test over an indentation depth range from about 100 nm to about 500 nm from the outer surface of the optical film structure,
the article exhibits an average photopic transmittance of greater than 80%,
the article exhibits a transmitted color √(a *2 +b *2 ) with a D65 illuminant of less than 4 at incident angles from 0 degrees to 10 degrees.

2. The article of claim 1 , wherein the glass-ceramic substrate comprises:
a crystallinity of at least 40% by weight,
a surface compressive stress of from 200 MPa to 400 MPa;
a depth of compression (DOC) of from about 0.08⋅t to about 0.25⋅t, where t is a thickness in mm of the glass-ceramic substrate; and,
a maximum central tension (CT) value from 80 MPa to 200 MPa; and,
wherein the glass-ceramic substrate has a thickness of about 1.5 mm or less.

3. The article of claim 1 , wherein the glass-ceramic substrate comprises a crystallinity of at least 75% by weight, a lithium disilicate phase, and a petalite phase, and
wherein the article exhibits an average photopic transmittance of greater than 80%.

4. A display device comprising the article of claim 1 , wherein the article serves as a protective cover for the display device.

5. An article, comprising:
a glass-ceramic substrate comprising a first primary surface and a second primary surface, the first primary surface and the second primary surface opposing one another; and
an optical film structure defining an outer surface, the optical film structure disposed on the first primary surface,
wherein the glass-ceramic substrate comprises an elastic modulus of greater than 85 GPa and a fracture toughness of greater than 0.8 MPa·√m,
the optical film structure comprises a plurality of alternating high refractive index (RI) and low RI layers;
the optical film structure comprises a scratch-resistant layer, and outer structure and an inner structure, the scratch-resistant layer disposed between the outer and inner structures, and the scratch-resistant layer has a thickness from about 100 nm to about 10,000 nm.

6. The article of claim 5 , wherein each high RI layer and the scratch-resistant layer comprises a silicon nitride or a silicon oxynitride, and each low RI layer comprises a silicon-containing oxide.

7. The article of claim 5 , wherein the glass-ceramic substrate has a refractive index of about 1.52 or greater, and further wherein the inner structure of the optical film structure is configured to substantially match an optical impedance between the glass-ceramic substrate and the scratch-resistant layer.

8. An article, comprising:
a glass-ceramic substrate comprising a first primary surface and a second primary surface, the first primary surface and the second primary surface opposing one another; and
an optical film structure comprising an inner surface and an outer surface, the inner surface of the optical film structure disposed on the first primary surface,
wherein the glass-ceramic substrate comprises an elastic modulus of greater than 85 GPa and a fracture toughness of greater than 0.8 MPa·√m, and
further wherein the optical film structure exhibits a residual compressive stress of greater than or equal to 700 MPa and an elastic modulus of greater than or equal to 140 GPa.

9. The article of claim 8 , wherein the glass-ceramic substrate comprises a crystallinity of at least 75% by weight, a lithium disilicate phase, and a petalite phase, and
wherein the article exhibits an average photopic transmittance of greater than 80%.

10. The article of claim 8 , wherein:
the article exhibits a maximum hardness of greater than 10 GPa, as measured by a Berkovich Hardness Test over an indentation depth range from about 100 nm to about 500 nm from the outer surface of the optical film structure,
the article exhibits an average photopic transmittance of greater than 80%,
the article exhibits a transmitted color √(a *2 +b *2 ) with a D65 illuminant of less than 4 at incident angles from 0 degrees to 10 degrees.

11. The article of claim 8 , wherein the glass-ceramic substrate comprises:
a crystallinity of at least 40% by weight,
a surface compressive stress of from 200 MPa to 400 MPa;
a depth of compression (DOC) of from about 0.08⋅t to about 0.25⋅t, where t is a thickness in mm of the glass-ceramic substrate;
a maximum central tension (CT) value from 80 MPa to 200 MPa, and,
wherein the glass-ceramic substrate has a thickness of about 1.5 mm or less.

12. A display device comprising the article of claim 11 , wherein the article serves as a protective cover for the display device.

13. The article of claim 8 , wherein:
the optical film structure comprises a plurality of alternating high refractive index (RI) and low RI layers;
the optical film structure comprises a scratch-resistant layer, and outer structure and an inner structure, the scratch-resistant layer disposed between the outer and inner structures, and the scratch-resistant layer has a thickness from about 100 nm to about 10,000 nm.

14. The article of claim 13 , wherein each high RI layer and the scratch-resistant layer comprises a silicon nitride or a silicon oxynitride, and each low RI layer comprises a silicon-containing oxide.

15. The article of claim 13 , wherein the glass-ceramic substrate has a refractive index of about 1.52 or greater, and further wherein the inner structure of the optical film structure is configured to substantially match an optical impedance between the glass-ceramic substrate and the scratch-resistant layer.

16. An article, comprising:
a glass-ceramic substrate comprising a first primary surface and a second primary surface, the first primary surface and the second primary surface opposing one another,
an optical film structure comprising an inner surface and an outer surface, the inner surface of the optical film structure disposed on the first primary surface,
wherein the glass-ceramic substrate comprises an elastic modulus of greater than 85 GPa and a fracture toughness of greater than 0.8 MPa·√m,
wherein the optical film structure exhibits a residual compressive stress of from 700 MPa to 1100 MPa and an elastic modulus of from 140 GPa to 200 GPa, and,
further wherein the article exhibits an average failure stress of 700 MPa or greater in a ring-on-ring test with the outer surface of the optical film structure placed in tension.

17. The article of claim 16 , wherein the glass-ceramic substrate comprises:
a crystallinity of at least 40% by weight,
a surface compressive stress of from 200 MPa to 400 MPa;
a depth of compression (DOC) of from about 0.08⋅t to about 0.25⋅t, where t is a thickness in mm of the glass-ceramic substrate;
a maximum central tension (CT) value from 80 MPa to 200 MPa, and,
wherein the glass-ceramic substrate has a thickness of about 1.5 mm or less.

18. The article of claim 16 , wherein the glass-ceramic substrate comprises a crystallinity of at least 75% by weight, a lithium disilicate phase and a petalite phase, wherein the article exhib

Assignees

• Corning Inc

Inventors

• Amin Jaymin
• Harris Jason Thomas
• Hart Shandon Dee
• Kim Chang-Gyu
• Koch Iii Karl William
• Kosik Williams Carlo Anthony
• Lin Lin
• Moon Dong-Gun
• Oh Jeonghong
• Price James Joseph
• Smith Charlene Marie
• Subramanian Ananthanarayanan
• Ukrainczyk Ljerka
• Xu Tingge

Classifications

• C03C17/3435

  comprising a nitride, oxynitride, boronitride or carbonitride · CPC title

• C03C10/0027 Primary

  containing SiO2, Al2O3, Li2O as main constituents · CPC title

• G02B1/14 Primary

  Protective coatings, e.g. hard coatings · CPC title

• G02B1/115

  Multilayers · CPC title

• G02B5/285

  comprising deposited thin solid films (G02B5/281 - G02B5/289 take precedence; multilayered film filters for fibre optic multiplexing G02B6/29361) · CPC title