Durable anti-reflective articles

Patent metadata

Field	Value
Publication number	US-11267973-B2
Application number	US-201514707106-A
Country	US
Kind code	B2
Filing date	May 8, 2015
Priority date	May 12, 2014
Publication date	Mar 8, 2022
Grant date	Mar 8, 2022

Abstract

Embodiments of durable, anti-reflective articles are described. In one or more embodiments, the article includes a substrate and an anti-reflective coating disposed on the major surface. The article exhibits an average light transmittance of about 94% or greater over an optical wavelength regime and/or an average light reflectance of about 2% or less over the optical wavelength regime, as measured from an anti-reflective surface. In some embodiments, the article exhibits a maximum hardness of about 8 GPa or greater as measured by a Berkovich Indenter Hardness Test along an indentation depth of about 50 nm or greater and a b* value, in reflectance, in the range from about −5 to about 1 as measured on the anti-reflective surface only at all incidence illumination angles in the range from about 0 degrees to about 60 degrees under an International Commission on Illumination illuminant.

First claim

What is claimed is:

1. An article comprising:
a substrate having a major surface; and
an anti-reflective coating having a physical thickness of from about 0.2 μm to about 1 μm disposed on the major surface, the anti-reflective coating comprising an anti-reflective surface, wherein the anti-reflective coating comprises a plurality of alternating low and high refractive index layers that ranges from five (5) layers to seven (7) layers and comprises a first low refractive index (RI) layer of SiO 2 disposed on and in direct contact with the major surface, at least one additional low RI layer of SiO 2 , and at least one high RI layer, and wherein a total physical thickness of the high RI layers is greater than about 30% of the total physical thickness of the anti-reflective coating,
wherein each high RI layer consists of SiO x N y , or Si u Al v O x N y ,
wherein the first low RI layer disposed on and in direct contact with the major surface of the substrate has an optical thickness from about 15 nm to about 200 nm,
wherein each low RI layer has a refractive index from about 1.3 to about 1.7 and each high RI layer has a refractive index of greater than about 1.9,
wherein the article exhibits a maximum hardness of about 10 GPa or greater as measured by a Berkovich Indenter Hardness Test along an indentation depth of about 50 nm or greater, and
wherein the article exhibits:
a single side average visible photopic light reflectance of about 2% or less.

2. The article of claim 1 , wherein the article exhibits
article transmittance color coordinates in the (L*, a*, b*) colorimetry system at normal incidence under an International Commission on Illumination illuminant exhibiting a reference point color shift of less than about 2 from a reference point as measured at the anti-reflective surface, 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 at normal incidence under an International Commission on Illumination illuminant exhibiting a reference point color shift of less than about 5 from a reference point as measured at the anti-reflective surface, the reference point comprising at least one of the color coordinates (a*=0, b*=0), the color coordinates (a*=−2, b*=−2) and the reflectance color coordinates of the substrate,
wherein, when the reference point is the color coordinates (a*=0, b*=0), the color shift is defined by √((a* article ) 2 +(b* article ) 2 ),
wherein, when the reference point is the color coordinates (a*=−2, b*=−2), the color shift is defined by √((a* article +2) 2 +(b* article +2) 2 ), and
wherein, when the reference point is the color coordinates of the substrate, the color shift is defined by √((a* article −a* substrate )+(b* article −b* substrate ) 2 ).

3. The article of claim 1 , wherein the article exhibits about 1% haze or less, as measured using a hazemeter having an aperture, wherein the aperture has a diameter of about 8 mm, and
wherein the haze is measured after a 500-cycle abrasion using a Taber Test.

4. The article of claim 1 , wherein the article exhibits an average roughness Ra, as measured by atomic force microscopy, of about 12 nm or less, and
wherein the average roughness Ra is measured after a 500-cycle abrasion using a Taber Test.

5. The article of claim 1 , wherein the article exhibits 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, 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 scattered light intensity is measured after a 500-cycle abrasion using a Taber Test.

6. The article of claim 1 , wherein the article exhibits 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, 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 scattered light intensity is measured after a 500-cycle abrasion using a Taber Test.

7. The article of claim 1 , wherein a total physical thickness of the high RI layers is ≥200 nm.

8. The article of claim 1 , wherein the article exhibits a reflectance angular color shift of less than about 5, as measured on the anti-reflective surface, at all angles from normal incidence to an incident illumination angle in the range from about 20 degrees to about 60 degrees under a F2 illuminant, and wherein angular color shift is calculated using the equation √((a* 2 −a* 1 ) 2 +(b* 2 −b* 1 ) 2 ), with a* 1 , and b* 1 representing the coordinates of the article when viewed at normal incidence and a* 2 , and b* 2 representing the coordinates of the article when viewed at the incident illumination angle.

9. The article of claim 1 , exhibiting a reflectance spectra such that the maximum reflectance over a wavelength range from about 400 nm to about 480 nm (R400-max) is greater than the maximum reflectance over a wavelength range from about 500 nm to about 600 nm (R500-max) and the maximum reflectance over a wavelength range from about 640 nm to about 710 (R640-max), and
wherein the minimum reflectance over a wavelength range from about 400 nm to about 480 nm (R400-min) is optionally less than the minimum reflectance over a wavelength range from about 500 nm to about 600 nm (R500-min), and
wherein the minimum reflectance over a wavelength range from about 640 to about 710 (R640-min) is optionally less than R500-min.

10. The article of claim 1 , wherein the substrate comprises an amorphous substrate or a crystalline substrate.

11. The article of claim 10 , wherein the amorphous substrate comprises a glass selected from the group consisting of soda lime glass, alkali aluminosilicate glass, alkali containing borosilicate glass and alkali aluminoborosilicate glass.

12. The article of claim 10 , wherein the crystalline substrate comprises a glass-ceramic substrate.

13. The article of claim 11 , wherein the glass is chemically strengthened and comprises a compressive stress (CS) layer with a surface CS of at least 250 MPa extending within the chemically strengthened glass from a surface of the chemically strengthened glass to a depth of layer (DOL) of at least about 10 μm.

14. The article of claim 1 , further comprising any one or more of an easy-to-clean coating, a diamond-like carbon coating, and a scratch resistant coating, disposed on the anti-reflective coating.

15. The article of claim 1 , wherein the anti-reflective coating comprises a single-sided reflectance of ≤2% over the range of 450 nm to 650 nm for angles of incidence from 0° to 40°.

16. The article of claim 1 , wherein the anti-reflective coating has a physical thickness of from about 350 nm to about 1 μm.

17. The article of claim 1 , wherein the total physical thickness of the high RI layers is greater than about 30% and less than 45% of the total thickness of the anti-reflective coating.

18. An electronic product incorporating the article according to claim 1 , wherein the article is a cover article configured to: (a) protect devices within the product, (b) provide a user interface for input, and/or (c) provide a display.

19. The article of claim 1 , wherein the plurality of alternating low and high refractive index layers is five (5) layers.

20. The article of claim 1

Assignees

• Corning Inc

Inventors

• Amin Jaymin
• Hart Shandon Dee
• Koch Iii Karl William
• Null Eric Louis
• Ouyang Xu
• Paulson Charles Andrew
• Price James Joseph

Classifications

• C03C17/3435 Primary

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

• C03C21/002

  to perform ion-exchange between alkali ions (C03C21/005 takes precedence) · CPC title

• C03C2217/78

  Coatings specially designed to be durable, e.g. scratch-resistant · CPC title

• C03C2217/734

  comprising an alternation of high and low refractive indexes · CPC title

• G02B1/115 Primary

  Multilayers · CPC title