Scratch-Resistant Articles with Retained Optical Properties

• US 20140377522A1
• Filed: 09/09/2014
• Published: 12/25/2014
• Est. Priority Date: 05/07/2013
• Status: Active Grant

• Current Assignee: Corning Incorporated
• Original Assignee: Corning Incorporated
• Inventors: Koch, Karl William III, Paulson, Charles Andrew
• Granted Patent: US 9,684,097 B2
• Time in Patent Office: Days
• US Class Current: 428/213
• CPC Class Codes: C03C 17/3435 comprising a nitride, oxynitride, boronitride or carbonitride
• CPC Class Codes: C03C 21/002 to perform ion-exchange between alkali ions C03C21/005 takes precedence
• CPC Class Codes: C03C 2217/78 Coatings specially designed to be durable, e.g. scratch-resistant
• CPC Class Codes: C03C 2217/91 Coatings containing at least one layer having a composition gradient through its thickness
• CPC Class Codes: C03C 3/091 containing aluminium
• CPC Class Codes: C23C 14/0036 Reactive sputtering
• CPC Class Codes: C23C 14/0084 Producing gradient compositions
• CPC Class Codes: C23C 14/0641 Nitrides C23C14/0617 takes precedence
• CPC Class Codes: C23C 14/0676 Oxynitrides
• CPC Class Codes: C23C 14/081 of aluminium, magnesium or beryllium
• CPC Class Codes: C23C 14/10 Glass or silica
• CPC Class Codes: G02B 1/14 Protective coatings, e.g. hard coatings
• CPC Class Codes: G02B 5/22 Absorbing filters G02B5/201 - G02B5/208 take precedence
• CPC Class Codes: G02B 5/26 Reflecting filters G02B5/28 takes precedence
• CPC Class Codes: Y10T 428/2495 Thickness [relative or absolute]
• CPC Class Codes: Y10T 428/26 Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension

Abstract

One or more aspects of the disclosure pertain to an article including an optical film structure disposed on a substrate, which may include a strengthened or non-strengthened substrate that may be amorphous or crystalline, such that the article exhibits scratch resistance and retains the same or improved optical properties as the substrate, without the optical film structure disposed thereon. In one or more embodiments, the article exhibits an average transmittance of 85% or more, over the visible spectrum (e.g., 380 nm-780 nm). Embodiments of the optical film structure include aluminum-containing oxides, aluminum-containing oxy-nitrides, aluminum-containing nitrides (e.g., AlN) and combinations thereof. The optical film structures disclosed herein also include a transparent dielectric including oxides such as silicon oxide, germanium oxide, aluminum oxide and a combination thereof. Methods of forming such articles are also provided.

Claims

1. A transparent article comprising:

a substrate having opposing major surfaces; and

an optical film structure disposed on a first major surface of the substrate forming a front face,

wherein the article comprises

a maximum hardness of about 12 GPa or greater, as measured on the front face by a Berkovich Indenter Hardness Test along an indentation depth of about 100 nm or greater, and

any one or more of;

article transmittance color coordinates in the (L*, a*, b*) colorimetry system exhibiting a color shift of less than about 2 from a reference point as measured at the front face, the reference point comprising at least one of the color coordinates (a*=0, b*=0) and the transmittance color coordinates of the substrate, and

article reflectance color coordinates in the (L*, a*, b*) colorimetry system exhibiting a color shift of less than about 2 from a reference point as measured at the front face, the reference point comprising at least one of the color coordinates (a*=0, b*=0) and the reflectance color coordinates of the substrate,

wherein the color shift is defined by √

((a*_article−

a*_substrate)²+(b*_article−

b*_substrate)²).

2. The transparent article of claim 1, wherein the article comprises an average transmittance of 85% or more, over the visible spectrum as measured at the front face.

3. The transparent article of claim 1, further comprising a scratch resistance such that, when the front face is scratched with a Berkovich indenter using a load of 160 mN at a speed of 10 μ

m/seconds for at least a length of 100 μ

m along the surface of the article, a scratch having a scratch depth of less than 250 nm is formed.

4. The transparent article of claim 1, further comprising a scratch resistance such that, when the front face is scratched with a Berkovich indenter using a load of 160 mN at a speed of 10 μ

m/seconds for at least a length of 100 μ

m along the surface of the article, a scratch having a scratch width of less than 10 μ

m is formed.

5. The transparent article of claim 1, wherein the article comprises a maximum hardness of about 12 GPa or greater, as measured on the front face by a Berkovich Indenter Hardness Test along an indentation depth in the range from about 200 nm to about 600 nm.

6. The transparent article of claim 1, wherein the optical film structure comprises one of a silicon-containing oxide, a silicon-containing oxy-nitride, silicon nitride, aluminum nitride, an aluminum-containing oxy-nitride, an aluminum-containing oxide, silicon aluminum oxy-nitride or a combination thereof.

7. The transparent article of claim 1, wherein the optical film structure comprises at least two layers, wherein a first layer is disposed between the substrate and a second layer.

8. The transparent article of claim 7, wherein the first layer comprises at least one of silicon-containing oxide, a silicon-containing oxy-nitride, silicon nitride, aluminum nitride, an aluminum-containing oxy-nitride, an aluminum-containing oxide, and silicon aluminum oxy-nitride, and wherein the second layer comprises at least one of SiO₂, GeO₂, and Al₂O₃.

9. The transparent article of claim 7, wherein the first layer comprises Al₂O₃, AlN, AlO_xN_y or combinations thereof.

10. The transparent article of claim 7, wherein the first layer comprises a first sub-layer comprising Al₂O₃ and a second sub-layer comprising AlN and, wherein the first sub-layer is disposed between the substrate and the second sub-layer.

11. The transparent article of claim 7, wherein the first layer comprises a first sub-layer comprising AlO_xN_y and a second sub-layer comprising AlN and, wherein the first sub-layer is disposed between the substrate and the second sub-layer.

12. The transparent article of claim 7, wherein the first layer further comprises SiO₂.

13. The transparent article of claim 1, wherein the optical film structure comprises a first layer and a second layer, wherein the first layer has a thickness greater than the thickness of the second layer.

14. The transparent article of claim 13, wherein the optical film structure has a thickness of 2 μ

m or greater.

15. The transparent article of claim 1, wherein the optical film structure comprises a compositional gradient comprising any one or more of an oxygen content gradient, a nitrogen content gradient, a silicon content gradient and an aluminum content gradient.

16. The transparent article of claim 1, wherein the substrate comprises a crystalline substrate.

17. The transparent article of claim 1, further comprising an interlayer disposed between the optical film structure and the substrate, wherein the interlayer comprises a polymer.

18. An article comprising:

a substrate having opposing major surfaces;

an optical film structure disposed on a first major surface of the substrate forming a front face, the optical film structure comprising a first layer having a thickness of at least about 1 μ

m and comprising an aluminum-containing nitride, an aluminum-containing oxy-nitride, an aluminum-containing oxide or a combination thereof, and a second layer disposed on the first layer,

wherein the article comprises a maximum hardness of 12 GPa or greater as measured on the front face by the Berkovich Indenter Hardness Test along an indentation depth of about 100 nm or greater, and

wherein the article comprises an average transmittance of 85% or more over the visible spectrum.

19. The article of claim 18, wherein the first layer comprises a first sub-layer, a second sub-layer and a third sub-layer, wherein the second sub-layer is disposed between the first sub-layer and the third sub-layer, and wherein the first and third sub-layers comprise AlN and the second sub-layer comprises SiO₂.

20. The article of claim 18, wherein the second layer comprises SiO₂, GeO₂, Al₂O₃, and a combination thereof.

21. The article of claim 18, wherein the optical film structure further comprises a modifier selected from BN, Ag, Cr and combinations thereof.

22. The article of claim 21, wherein the optical film structure comprises a coefficient of friction of less than 0.3, when measured against a silicon carbide sphere counter surface.

23. The article of claim 18, wherein the article comprises a maximum hardness of about 12 GPa or greater, as measured on the front face by a Berkovich Indenter Hardness Test along an indentation depth in the range from about 200 nm to about 600 nm.

24. The article of claim 18, wherein the article comprises at least one of:

article transmittance color coordinates in the (L*, a*, b*) colorimetry system comprising a color shift of less than about 2 from a reference point as measured at the front face, the reference point comprising at least one of the color coordinates (a*=0, b*=0) and the transmittance color coordinates of the substrate, and

article reflectance color coordinates in the (L*, a*, b*) colorimetry system comprising a color shift of less than about 2 from a reference point as measured at the front face, the reference point comprising at least one of the color coordinates (a*=0, b*=0) and the reflectance color coordinates of the substrate, and

wherein the color shift is defined by √

((a*_article−

a*_substrate)²+(b*_article−

b*_substrate)²).

25. The article of claim 18, wherein the article comprises a maximum hardness of about 16 GPa or greater, as measured on the front face by a Berkovich Indenter Hardness Test along an indentation depth of about 100 nm or greater.

26. The article of claim 18, wherein the optical film structure comprises a sensor layer.

27. A transparent article comprising:

a substrate having opposing major surfaces; and

an optical film structure disposed on a first major surface of the substrate forming a front face,

wherein the article comprises any one or more of;

article transmittance color coordinates in the (L*, a*, b*) colorimetry system exhibiting a color shift of less than about 2 from a reference point as measured at the front face, the reference point comprising at least one of the color coordinates (a*=0, b*=0) and the transmittance color coordinates of the substrate, and

article reflectance color coordinates in the (L*, a*, b*) colorimetry system exhibiting a color shift of less than about 2 from a reference point as measured at the front face, the reference point comprising at least one of the color coordinates (a*=0, b*=0) and the reflectance color coordinates of the substrate,

wherein the color shift is defined by √

((a*_article−

a*_substrate)²+(b*_article−

b*_substrate)²), and

wherein the article comprises an abrasion resistance comprising any one or more of;

about 5% haze or less, as measured using a hazemeter having an aperture, wherein the aperture has a diameter of about 8 mm, and

a scattered light intensity of about 0.1 (in units of 1/steradian) or less, at a polar scattering angle in the range from about 15 degrees to about 60 degrees, as measured at normal incidence in transmission using an imaging sphere for scatter measurements, with a 2 mm aperture at 600 nm wavelength, and

wherein the abrasion resistance is measured after a 500-cycle abrasion on the front face using a Taber Test.

28. The transparent article of claim 27, wherein the abrasion resistance comprises about 1% haze or less.

29. The transparent article of claim 27, wherein the abrasion resistance comprises a scattered light intensity of about 0.05 (in units of 1/steradian) or less, at a polar scattering angle of about 40 degrees or less.

30. The transparent article of claim 27, wherein the abrasion resistance comprises a scattered light intensity of about 0.1 (in units of 1/steradian) or less, at a polar scattering angle of about 20 degrees or less.