Low contrast anti-reflection articles with reduced scratch and fingerprint visibility

• US 10,620,344 B2
• Filed: 05/22/2015
• Issued: 04/14/2020
• Est. Priority Date: 05/23/2014
• Status: Active Grant

• Current Assignee: Corning Incorporated
• Original Assignee: Corning Incorporated
• Inventors: Hart, Shandon Dee, Koch, Karl William, Paulson, Charles Andrew
• Primary Examiner(s): Frost, Anthony J
• Application Number:
  US15/313,733
• Publication Number:
  US 20170199307A1
• Time in Patent Office: 1,789 Days
• CPC Class Codes: C03C 17/3417 all coatings being oxide coatings
• CPC Class Codes: C03C 17/3435 comprising a nitride, oxynitride, boronitride or carbonitride
• CPC Class Codes: C03C 2217/734 comprising an alternation of high and low refractive indexes
• CPC Class Codes: G02B 1/11 Anti-reflection coatings
• CPC Class Codes: G02B 1/115 Multilayers

Abstract

Embodiments of articles including a low-contrast anti-reflection coating are disclosed. The coated surface of such articles exhibits a reduced difference in reflectance between a pristine state and when a surface defect is present. In one or more embodiments, the coated surface of such articles exhibits a first average reflectance in the range from about 0.6% to about 6.0% in a pristine condition and a second average reflectance of about 8% or less after removal of a surface thickness of the anti-reflection coating. In other embodiments, the coated substrate exhibits a second average reflectance of about 10% or less, when the coated surface comprises a contaminant. In some embodiments, the coated substrate exhibits a first color coordinate (a*₁, b*₁) in a pristine condition and a second color coordinate (a*₂, b*₂) after the presence of a surface defect such that Δa*b* is about 6 or less.

Claims

1. An article comprising:

a substrate having a substrate surface; and

an anti-reflection coating disposed on the substrate surface forming a coated surface, wherein the anti-reflection coating comprises a first low RI sub-layer and a second high RI sub-layer,

wherein the first low RI sub-layer comprises SiO₂,

wherein the second high RI sub-layer comprises Si_uAl_vO_xN_y, AlO_xN_y, or combinations thereof,

wherein the coated surface exhibits a first average reflectance when the coated surface is in a pristine condition, and a second average reflectance after removal of a surface thickness of about 20 nm to about 500 nm of the anti-reflection coating from the coated surface that provides a contrast ratio (the second average reflectance;

the first average reflectance) in the range from about 0.5 to about 10, over the visible spectrum, wherein the anti-reflection coating has a thickness that is greater than the surface thickness and wherein the reflectance is measured under a CIE illuminant.

2. The article of claim 1, wherein the first average reflectance is in the range from about 0.6% to about 6% over at least a portion of the visible spectrum in the range from about 450 nm to about 650 nm and the second average reflectance is about 8% or less over the visible spectrum.

3. The article of claim 1, wherein the anti-reflection coating comprises a first layer disposed on the substrate surface and a second layer having a layer thickness disposed on the first layer, wherein the surface thickness is greater than or equal to the layer thickness of the second layer.

4. The article of claim 1, wherein at least one of the first reflectance and the second reflectance comprises an average oscillation amplitude of about 2% absolute reflectance or less, over the visible spectrum.

5. The article of claim 4, wherein over a wavelength width of about 100 nm within the visible spectrum, at least one of the first reflectance and the second reflectance comprises a maximum oscillation amplitude of about 2% absolute reflectance or less.

6. The article of claim 4, wherein the reflectance is measured at an incident illumination angle in the range from about 0 degrees to about 60 degrees.

7. The article of claim 4, wherein at least one of the first reflectance and the second reflectance comprises reflectance oscillations of less than 20% relative to a mean reflectance value, over the visible spectrum.

8. The article of claim 7, wherein the second average reflectance is less than about 3%.

9. The article of claim 8, wherein the surface thickness is about 20 nm to about 25 nm, wherein the second average reflectance comprises about 6% or less, and wherein the coated surface exhibits a contrast ratio (the second average reflectance:

the first average reflectance) in the range from about 0.5 to about 10, over the visible spectrum.

10. The article of claim 8, wherein the surface thickness is about 20 nm to about 50 nm, wherein the second average reflectance comprises about 8% or less, and wherein the coated surface exhibits a contrast ratio (the second average reflectance:

the first average reflectance) in the range from about 0.5 to about 20, over the visible spectrum.

11. The article of claim 8, wherein the surface thickness is about 20 nm to about 500 nm, wherein the second average reflectance comprises about 12% or less, and wherein the coated surface exhibits a contrast ratio (the second average reflectance:

the first average reflectance) in the range from about 0.5 to about 50, over the visible spectrum.

12. The article of claim 8, wherein the coated surface exhibits a contrast ratio of (the second average reflectance:

the first average reflectance) of about less than 10, over the visible spectrum, and wherein the first average reflectance and the second average reflectance are measured under an incident illumination angle in the range from about 0 degrees to about 60 degrees.

13. The article of claim 8, wherein the contrast ratio comprises oscillations having an average amplitude of about 1 or less in absolute ratio units, over the visible spectrum.

14. The article of claim 1, wherein the first average reflectance and the second average reflectance are measured under an incident illumination angle in the range from about 0 degrees to about 60 degrees.

18. The article of claim 1,

wherein the coated surface exhibits a first color coordinate (a*₁, b*₁), when measured using an incident illumination angle in the range from about 0 degrees to about 75 degrees from normal incidence under an illuminant in a pristine condition, and a second color coordinate (a*₂, b*₂), when measured using the incident illumination angle under the illuminant after removal of a surface thickness in the range from about 0.1 nm to about 140 nm of the anti-reflection coating from the coated surface, and

wherein Δ

a*b* is about 6 or less.

19. The article of claim 18, wherein the article exhibits a hardness of about 5 GPa or greater as measured on the coated surface by a Berkovitch Indentation Hardness test over an indentation depth of about 100 nm or greater from the coated surface.

20. The article of claim 19, wherein the incident illumination angle is about 60 degrees, wherein the surface thickness is in a range from about 0.1 to about 100 nm, and wherein Δ

a*b* is less than about 3.

15. An article comprising:

a substrate having a surface; and

an anti-reflection coating disposed on the surface forming a coated surface,

wherein the anti-reflection coating comprises a first low RI sub-layer and a second high RI sub-layer,

wherein the first low RI sub-layer comprises SiO₂,

wherein the second high RI sub-layer comprises Si_uAl_vO_xN_y, AlO_xN_y, or combinations thereof,

wherein the coated surface of the article exhibits a first average reflectance in the range from about 0.6% to about 6.0% over a visible spectrum in the range from about 450 to about 650 nm as tested when the article is in a pristine condition, and a second average reflectance of about 10% or less over the visible spectrum as tested when the coated surface comprises a layer of fingerprint-simulating medium having a thickness in the range from about 100 nm to about 2000 nm, wherein the fingerprint-simulating medium comprises a refractive index of 1.4-1.6.

16. The article of claim 15, wherein the ratio of the second average reflectance:

the first average reflectance is about 20 or less, and the ratio comprises oscillations having an average amplitude of about 10 or less in absolute ratio units, over the visible spectrum.

17. The article of claim 15, wherein when the coated surface comprises the layer of fingerprint-simulating medium, the coated surface comprises a maximum reflectance value of about 8% absolute reflectance or less and a maximum oscillation amplitude of about 7.5% absolute reflectance or less, across the visible spectrum.