Air oxidizable scratch resistant protective layer for optical coatings
The present invention provides a scratch protecting layer comprising a metal, metal alloy, metal compound or an intermetallic layer deposited on an air contacting surface. The scratch protecting layer is typically from 1 to 3 nanometers thick and not optically absorbing after oxidation occurs. This layer is initially deposited in a primarily unoxidized or un-nitrided state. Full oxidation of the metal, metal alloy, metal compound or intermetallic layer occurs within several days after exposure to air. The scratch protection layer can be 2 to 5 nanometers thick if the layer is exposed to a plasma, electrical discharge or ion beam comprising a reactive gas such as oxygen or nitrogen.
1 . An article with improved scratch protection, comprising
a substrate,
an optical coating comprising one or more layers on the substrate, and
an outermost scratch protection layer comprising a protective metal, metal alloy, metal compound or intermetallic coating, wherein said outermost scratch protection layer is 1 to 3 nm thick.
2 . The article according to claim 1 , wherein said metal is fully oxidized.
3 . The article according to claim 1 , wherein the metal portion of said metal alloy or metal compound is selected from the group consisting of chromium, iron, titanium, zirconium, hafnium, niobium, tantalum, molybdenum, tungsten, iron, aluminum and silicon.
4 . The article according to claim 3 , wherein said metal portion is zirconium.
5 . The article according to claim 1 , wherein the metal is zirconium.
6 . The article according to claim 1 , wherein said substrate is a transparent substrate.
7 . The article according to claim 6 , wherein said transparent substrate is glass with optical coatings deposited on it.
8 . The article according to claim 7 , wherein said optical coatings comprise one or more layers of NiCrO x , Ag, and SiAlN x .
9 . The article according to claim 8 , wherein the metal is zirconium.
10 . The article according to claim 1 , wherein the outermost scratch protection layer does not change the spectral reflectance and/or transmission in the visible or infrared wavelengths of the article.
11 . The article according to claim 1 , wherein the outermost scratch protection layer is deposited onto a layer of SiAlOxNy.
12 . An article with improved scratch protection, comprising
a substrate,
an optical coating comprising one or more layers on the substrate, and
an outermost scratch protection layer comprising a protective metal, wherein said outermost scratch protection layer is 2 to 5 nm thick.
13 . A method for improving the scratch protection of optical coatings on an article, comprising
depositing an optical coating comprising one or more layers on an article,
depositing a 1-3 nm layer comprising an unoxidized metal, metal alloy, metal compound or intermetallic on said optical coating to provide a scratch protection layer, and
oxidizing said metal, metal alloy, metal compound or intermetallic layer.
14 . The method according to claim 13 , wherein the metal portion of said metal alloy or metal compound is selected from the group consisting of chromium, iron, titanium, zirconium, hafnium, niobium, tantalum, molybdenum, tungsten, iron, nickel, aluminum and silicon.
15 . The method according to claim 14 , wherein said metal portion is zirconium.
16 . The method according to claim 13 , wherein said substrate is a transparent article.
17 . The method according to claim 13 , wherein said substrate is glass.
18 . The method according to claim 13 , wherein said optical coating includes one or more layers of NiCrO x , Ag, and SiAlN x .
19 . The method according to claim 13 , wherein said metal, metal alloy, metal compound or intermetallic layer is oxidized by exposure to air.
20 . The method according to claim 13 , wherein said scratch protection layer is deposited onto a layer of SiAlOxNy.
21 . The method according to claim 13 , wherein said metal has an oxide heat of formation less than −150 kCal/mole and a melting point of greater than 1600 degrees centigrade.
22 . The method according to claim 21 , wherein said metal has a heat of formation less than −200 kCal/mole and a melting point greater than 1600 degrees centigrade.
23 . The method according to claim 13 , wherein said metal oxidizes in ambient air to a substantially transparent state within 250 hours after the metal is deposited.
24 . The method according to claim 23 , wherein said metal oxidizes to a substantially transparent state within 25 hours after the metal is deposited.
25 . The method according to claim 24 , wherein said metal oxidizes to a substantially transparent state within 1 hour after the metal is deposited.
26 . A method for improving scratch protection of an article with an optical coating, comprising
depositing an optical coating comprising one or more layers on an article,
depositing a 2-5 nm layer comprising an unoxidized metal, metal alloy, metal compound or intermetallic layer on said optical coating to provide a scratch protection layer, and
oxidizing said metal, metal alloy, metal compound or intermetallic layer by exposure to a plasma, electrical discharge or ion beam comprising a reactive gas.
27 . The method according to claim 26 , wherein said reactive gas is oxygen or nitrogen.