Hardcoated glass-ceramic articles

Patent metadata

Field	Value
Publication number	US-10914867-B2
Application number	US-201815927619-A
Country	US
Kind code	B2
Filing date	Mar 21, 2018
Priority date	Mar 21, 2017
Publication date	Feb 9, 2021
Grant date	Feb 9, 2021

Abstract

According to one embodiment, there is an article including a glass-ceramic substrate having a major surface, an optical coating is disposed on the major surface and forms an appearance-enhancing surface, the optical coating including a appearance-enhancing coating, and a scratch-resistant layer. The article exhibits a hardness of 8 GPa or more, and a photopic average diffuse light reflectance measured at the appearance-enhancing surface of one of: (i) about 0.3% or less; (ii) about 0.2% or less; (iii) about 0.1% or less, over an optical wavelength regime in the range from about 400 nm to about 800 nm. Further, in the (L*, a*, b*) colorimetry system of the International Commission on Illumination, at near-normal incidence, the article comprises a diffuse reflectance dE* of one of: (i) about 3 or less; (ii) about 2 or less; or (iii) about 1 or less, where dE* is defined as dE*=sqrt(L* 2 +a* 2 +b* 2 ).

First claim

What is claimed is:

1. An article comprising:
a glass-ceramic substrate having a major surface, wherein the substrate further comprises a black color; and
an optical coating disposed on the major surface and forming an appearance-enhancing surface, the optical coating comprising an appearance-enhancing coating, and a scratch-resistant layer, wherein the scratch-resistant layer comprises a thickness from about 0.5 μm to about 3 μm, wherein
the article comprises a hardness of 8 GPa or more,
the article exhibits a photopic average diffuse light reflectance measured at the appearance-enhancing surface of about 0.3% or less over an optical wavelength regime in the range from about 400 nm to about 800 nm,
wherein the appearance-enhancing coating comprises a plurality of layers that comprise a first low refractive index (RI) layer and a second high RI layer, and further wherein the appearance-enhancing coating comprises a plurality of periods such that the first low RI layer and the second high RI layer alternate,
wherein the appearance-enhancing coating comprises a first portion and a second portion, the scratch-resistant layer disposed between the first portion and the second portion,
wherein the plurality of layers comprises a nitride or an oxynitride material, and
further wherein the first portion of the appearance-enhancing coating is disposed over the scratch-resistant layer and comprises a total thickness of less than or equal to about 200 nm.

2. The article of claim 1 , the appearance-enhancing surface of the article comprises a photopic average total reflectance of less than about 4%.

3. The article of claim 1 , the appearance-enhancing surface comprises at least one of a total, a specular, and a diffuse reflected color, at near-normal incidence within a range of 0 to −8 in both a* and b*.

4. The article of claim 1 , at least one of total reflected color and specular reflected color having at least one of: (i) b*<0; (ii) b* from 0 to −10; and (iii) a* from 0 to −2.

5. The article of claim 1 , the diffuse reflected color is at least one of: (i) b* less than zero; (ii) b* from 0 to −2; (iii) b* from 0 to −1; and (iv) a* from −0.5 to 0.5.

6. The article of claim 1 , the ceramic component of the glass-ceramic comprises Fe2O3, TiO2, or MgO crystallites, the crystallites comprising an average size from about 5 nm to about 50 nm, the crystallites comprising a cross-sectional area fraction of less than about 15% of the overall cross-sectional area of the glass-ceramic substrate.

7. The article of claim 1 , the article exhibits a photopic average total light transmittance of about 10% or less over an optical wavelength regime in the range from about 400 nm to about 800 nm.

8. The article of claim 1 , wherein the article exhibits a hardness of about 10 GPa or greater at an indentation depth of about 100 nm and a hardness of about 16 GPa or greater at an indentation depth of about 500 nm as measured on the appearance-enhancing surface by a Berkovich Indenter Hardness Test.

9. The article of claim 1 , wherein the article exhibits an abrasion resistance after a 500-cycle abrasion using a Taber Test on the appearance-enhancing surface, wherein after abrasion the appearance-enhancing surface exhibits an average roughness Ra, as measured by atomic force microscopy, of about 12 nm or less.

10. The article of claim 1 , wherein the appearance-enhancing coating comprises a thickness and a plurality of layers comprising a nitride or oxy-nitride material, and where the combined thickness of the layers comprising a nitride or an oxyinitride is about 50% or greater of the thickness of the appearance-enhancing coating.

11. The article of claim 1 , comprising a scratch resistant layer, the scratch resistant layer comprising a high RI layer, and comprising the thickest layer in the appearance-enhancing coating.

12. The article of claim 1 , wherein at least one of (i) the layers positioned over the scratch resistant layer comprise a total thickness of less than or equal to about 200 nm; and (ii) each of the layers other than the scratch resistant layer comprises an optical thickness (n*d) in the range from about 2 nm to about 200 nm.

13. The article of claim 1 , wherein the scratch resistant layer comprises a high RI material, one or more of the layers positioned over the scratch resistant layer comprises a high RI material, and one or more of the layers positioned over the scratch resistant layer comprises a low RI material.

14. The article of claim 1 , wherein the uppermost 500 nm of the optical coating measured from the appearance-enhancing surface comprises at least one of:
less than about 30% of low RI material; and
at least about 70% of high RI material.

15. A device comprising:
a housing having front, back, and side surfaces;
electrical components that are at least partially inside the housing;
a display at or adjacent to the front surface of the housing; and
a cover substrate disposed over the display, wherein at least a portion of the housing comprises the article of claim 1 .

16. The article of claim 1 , wherein the first low RI layer comprises SiO 2 , the second high RI layer comprises AlO x N y , and the scratch-resistant layer comprises AlO x N y , wherein the plurality of periods of the appearance-enhancing coating is four periods, wherein the first and second portion of the appearance-enhancing coating comprises one period and three periods, respectively, and further wherein the optical coating comprises a capping layer over the first portion of the appearance-enhancing coating, the capping layer comprising SiO 2 .

17. An article comprising:
a glass-ceramic substrate having a major surface, wherein the substrate further comprises a black color; and
an optical coating disposed on the major surface and forming an appearance-enhancing surface, the optical coating comprising an appearance-enhancing coating, and a scratch-resistant layer, wherein the scratch-resistant layer comprises a thickness from about 0.5 μm to about 3 μm, wherein
the article comprises a hardness of 8 GPa or more,
the article exhibits a photopic average diffuse light reflectance measured at the appearance-enhancing surface of about 0.3% or less, over an optical wavelength regime in the range from about 400 nm to about 800 nm,
in the (L*, a*, b*) colorimetry system of the International Commission on Illumination, at near-normal incidence, the article comprises a diffuse reflectance dE* of about 3 or less, where dE* is defined as dE*=sqrt(L* 2 +a* 2 +b* 2 ),
wherein the appearance-enhancing coating comprises a plurality of layers that comprise a first low refractive index (RI) layer and a second high RI layer, and further wherein the appearance-enhancing coating comprises a plurality of periods such that the first low RI layer and the second high RI layer alternate,
wherein the appearance-enhancing coating comprises a first portion and a second portion, the scratch-resistant layer disposed between the first portion and the second portion,
wherein the plurality of layers comprises a nitride or an oxynitride material, and
further wherein the first portion of the appearance-enhancing coating is disposed over the scratch-resistant layer and comprises a total thickness of less than or equal to about 200 nm.

18. The article of claim 17 , wherein the first low RI layer comprises SiO 2 , the second high RI layer comprises AlO x N y , and the scratch-resistant layer comprises AlO x N y , wherein the plurality of periods of the appearance-enhancing coating is four periods, wherein the first a

Assignees

• Corning Inc

Inventors

• Amin Jaymin
• Hart Shandon Dee
• Kiczenski Timothy James
• Koch Iii Karl William
• Kosik Williams Carlo Anthony
• Mayolet Alexandre Michel
• Paulson Charles Andrew
• Price James Joseph

Classifications

• H05K5/03

  Covers · CPC title

• G02B27/0006

  with means to keep optical surfaces clean, e.g. by preventing or removing dirt, stains, contamination, condensation (G02B1/18 takes precedence; cleaning in general B08B) · CPC title

• G02B5/28

  Interference filters · CPC title

• G02B5/08

  Mirrors {(vehicle mirrors involving special optical features B60R1/08)} · CPC title

• G02B1/18

  Coatings for keeping optical surfaces clean, e.g. hydrophobic or photo-catalytic films (G02B1/16 takes precedence) · CPC title