Scratch-resistant articles with retained optical properties
One or more aspects of the disclosure pertain to an article including an optical film structure disposed on an inorganic oxide 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 inorganic oxide 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.
1. An article comprising:
an inorganic oxide substrate having opposing major surfaces; and
an optical film structure disposed on a first major surface of the inorganic oxide substrate,
wherein the optical film structure exhibits a scratch resistance, and wherein the article exhibits an average transmittance of 85% or more, over the visible spectrum,
wherein optical film structure comprises a hardness of about 16 GPa or greater as measured by a diamond Berkovitch indenter test,
wherein the article exhibits one or more of:
a color transmittance in the (L, a*, b*) colorimetry system having transmittance color coordinates when viewed at normal incidence, such that the distance between the transmittance color coordinates and a reference point is less than about 2, and
a color reflectance in the (L, a*, b*) colorimetry system having reflectance color coordinates when viewed at normal incidence, such that the distance between the reflectance color coordinates and a reference point is less than about 2, and
wherein the reference point comprises at least one of the color coordinates (a*=0, b*=0) and the color coordinates of the substrate, and
wherein, when the reference point is the color coordinates of the substrate, the distance equals √((a* article −a* substrate ) 2 +(b* article −b* substrate ) 2 ), and
wherein, when the reference point is the color coordinates (a*=0, b*=0), the distance equals √((a* article ) 2 +(b* article ) 2 ).
2. The article of claim 1 , wherein the article has a total reflectivity that is the same or less than a total reflectivity of the inorganic oxide substrate without the optical film structure disposed thereon.
3. The 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.
4. The article of claim 1 , wherein the optical film structure comprises at least two layers, wherein a first layer is disposed between the inorganic oxide substrate and a second layer.
5. The article of claim 4 , 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 SiO 2 , GeO 2 , and Al 2 O 3 .
6. The article of claim 4 , wherein the first layer comprises Al 2 O 3 , AlN, AlO x N y or combinations thereof.
7. The article of claim 4 , wherein the first layer comprises a first sub-layer comprising Al 2 O 3 and a second sub-layer comprising AlN and, wherein the first sub-layer is disposed between the inorganic oxide substrate and the second sub-layer.
8. The article of claim 4 , wherein the first layer comprises a first sub-layer comprising AlO x N y and a second sub-layer comprising AlN and, wherein the first sub-layer is disposed between the inorganic oxide substrate and the second sub-layer.
9. The article of claim 4 , wherein the first layer further comprises SiO 2 .
10. The 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.
11. The article of claim 10 , wherein the optical film structure has a thickness of 2 μm or greater.
12. The article of claim 1 , wherein the optical film structure comprises AlN, and wherein the AlN is doped with a modifier comprising one or more of BN, Ag, Cr, Mg and Ca.
13. The article of claim 1 , wherein the inorganic oxide substrate comprises a crystalline substrate or an amorphous substrate.
14. The article of claim 1 , further comprising an interlayer disposed between the optical film structure and the inorganic oxide substrate.
15. An article comprising:
an inorganic oxide substrate having opposing major surfaces;
an optical film structure disposed on a first major surface of the inorganic oxide substrate, the optical film structure comprising a first layer 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 optical film structure exhibits a hardness of 16 GPa or greater, as measured by a diamond Berkovitch indenter test,
wherein the article exhibits an average transmittance of 85% or more over the visible spectrum, and one or more of
a color transmittance in the (L, a*, b*) colorimetry system having transmittance color coordinates when viewed at normal incidence, such that the distance between the transmittance color coordinates and a reference point is less than about 2, and
a color reflectance in the (L, a*, b*) colorimetry system having reflectance color coordinates when viewed at normal incidence, such that the distance between the reflectance color coordinates and a reference point is less than about 2,
wherein the reference point comprising at least one of the color coordinates (a*=0, b*=0) and the color coordinates of the substrate, and
wherein, when the reference point is the color coordinates of the substrate, the distance equals √((a* article −a* substrate ) 2 +(b* article −b* substrate ) 2 ), and
wherein, when the reference point is the color coordinates (a*=0, b*=0), the distance equals √((a* article ) 2 +(b* article ) 2 ).
16. The article of claim 15 , 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 SiO 2 .
17. The article of claim 15 , wherein the second layer comprises SiO 2 , GeO 2 , Al 2 O 3 , and a combination thereof.
18. The article of claim 15 , wherein the optical film structure further comprises a modifier selected from BN, Ag, Cr and combinations thereof.
19. The article of claim 18 , wherein the optical film structure exhibits a coefficient of friction of less than 0.3, when measured against a silicon carbide sphere counter surface.