Coated article with ir reflecting layer and multilayer overcoat for reducing fingerprints

Abstract

A low-E (low emissivity) coating includes a multilayer overcoat designed for reducing fingerprints. The multilayer overcoat includes a layer comprising an oxide of zirconium (e.g., ZrO2) sandwiched between and contacting first and second layers of or including silicon nitride (e.g., Si3N4, SiOxNy, SiZrOxNy, or the like). The uppermost layer comprising silicon nitride modifies the surface energy of the layer comprising the oxide of zirconium so as to make the uppermost surface of the coating more hydrophilic, thereby reducing or minimizing interaction between zirconium oxide and finger oil to reduce fingerprints on the uppermost surface of the coating.

1 . A coated article including a coating supported by a glass substrate, the coating comprising:
 a layer comprising zinc oxide;   an infrared (IR) reflecting layer comprising silver;   a layer comprising metal oxide; and   a multilayer overcoat comprising silicon nitride and an oxide of zirconium, wherein the silicon nitride is exposed to ambient atmosphere after the coated article is made;   wherein the coated article, measured monolithically, has a visible transmission of at least 60%.   
     
     
         2 . The coated article of  claim 1 , wherein the silicon nitride further comprises oxygen. 
     
     
         3 . The coated article of  claim 1 , wherein the silicon nitride further comprises zirconium silicon oxynitride. 
     
     
         4 . The coated article of  claim 1 , wherein the multilayer overcoat is further doped with Al. 
     
     
         5 . The coated article of  claim 1 , wherein the coating further comprises a layer comprising zirconium silicon oxynitride on the glass substrate. 
     
     
         6 . The coated article of  claim 1 , wherein the coating further comprises a layer comprising titanium oxide. 
     
     
         7 . The coated article of  claim 1 , wherein the coating further comprises a dielectric layer comprising zinc stannate located between at least the layer comprising titanium oxide and the layer comprising zinc oxide. 
     
     
         8 . The coated article of  claim 1 , wherein the coating further comprises a layer comprising nickel alloy oxide. 
     
     
         9 . The coated article of  claim 1 , wherein the coating further comprises a layer comprising tin and oxygen located between at least the layer comprising metal oxide and the multilayer overcoat. 
     
     
         10 . The coated article of  claim 1 , wherein the layer comprising zirconium silicon oxynitride has a nitrogen to oxygen ratio (nitrogen/oxygen ratio) of at least 1. 
     
     
         11 . The coated article of  claim 2 , wherein multilayer overcoat comprising zirconium silicon oxynitride has a nitrogen to oxygen ratio (nitrogen/oxygen ratio) of at least 1. 
     
     
         12 . The coated article of  claim 2 , wherein the multilayer overcoat comprising zirconium silicon oxynitride has a nitrogen to oxygen ratio (nitrogen/oxygen ratio) of at least 2. 
     
     
         13 . The coated article of  claim 6 , wherein the layer comprising titanium oxide has a titanium to oxygen ratio from 1.5 to 2.5. 
     
     
         14 . The coated article of  claim 6 , wherein the layer comprising titanium oxide has an index of refraction at 550 nm of at least 2.0. 
     
     
         15 . The coated article of  claim 7 , wherein the layer comprising zinc stannate has more Zn than Sn by weight. 
     
     
         16 . The coated article of  claim 1 , wherein the multilayer overcoat causes a contact angle of the coating to decrease, compared to if zirconium oxide in the multilayer overcoat is exposed to ambient atmosphere after the coated article is made, by at least 15 degrees. 
     
     
         17 . The coated article of  claim 1 , wherein the coating has a contact angle of no greater than 60 degrees. 
     
     
         18 . The coated article of  claim 1 , wherein the coating contains only one silver based IR reflecting layer, and wherein the coating has a normal emissivity (En) of no greater than 7%. 
     
     
         19 . An IG window unit comprising the coated article of  claim 1 , wherein the IG window unit has a U-value of no greater than 1.4, the IG window unit further comprising another glass substrate, and wherein the coating is on surface two or surface three of the IG window unit. 
     
     
         20 . A method for making a coated article comprising:
 having a coating supported by a glass substrate,   wherein the coating comprising:   a layer comprising zinc oxide;   an infrared (IR) reflecting layer comprising silver;   a layer comprising metal oxide; and   a multilayer overcoat comprising silicon nitride and an oxide of zirconium, wherein the silicon nitride is exposed to ambient atmosphere after the coated article is made;   wherein the coated article, measured monolithically, has a visible transmission of at least 60%.