Ig window unit having triple silver coating and dielectric coating on opposite sides of glass substrate

Abstract

An insulating glass (IG) window unit including first and second glass substrates that are spaced apart from each other. At least one of the glass substrate has a triple silver low-emissivity (low-E) coating on one major side thereof, and a dielectric coating for improving angular stability on the other major side thereof

1 - 13 . (canceled) 
     
     
         14 . An insulating glass (IG) widow unit comprising:
 first and second glass substrates;   wherein the first glass substrate supports a low-E coating and an angular reduction dielectric coating on respective opposite major surfaces thereof, respectively;   wherein the low-E coating comprises a plurality of infrared (IR) reflecting layers, wherein at least a first dielectric layer of the low-E coating is provided between at least first and second of the IR reflecting layers;   wherein the angular reduction dielectric coating, which is on a side of the first glass substrate opposite the low-E coating, comprises a plurality of high index and low index layers, wherein at least one high index layer of the angular reduction dielectric coating comprises an oxide of titanium and/or niobium; and   wherein the low-E coating and the angular reduction dielectric coating are configured so that the IG window unit has a AC value of no greater than 3.0 as viewed from an exterior of the IG window unit across a range of angles of at least 85 degrees from a normal viewing angle which is perpendicular to the IG window unit, and   wherein AC is defined as
   Δ C =[( a−a   o ) 2 +[( b−b   o ) 2 ] 1/2  
 
   where “a” is an a* color value at the normal viewing angle, and “a o ” is an a* color viewing angle at the off-axis viewing angle, “b” is a b* color value at the normal viewing angle, and “b o ” is a b* color viewing angle at the off-axis viewing angle.   
     
     
         15 . The IG window unit of  claim 14 , wherein the low-E coating and the dielectric coating are configured so that the IG window unit has an LSG value of at least 2.2, and a ΔC value of no greater than 2.5 as viewed from an exterior of a building in which the IG window unit is to be mounted across a range of angles of at least 85 degrees. 
     
     
         16 . The IG window unit of  claim 14 , wherein the low-E coating and the dielectric coating are configured so that the IG window unit has an LSG value of at least 2.3, and a ΔC value of no greater than 2.0 as viewed from an exterior of a building in which the IG window unit is to be mounted across a range of angles of at least 85 degrees. 
     
     
         17 . The IG window unit of  claim 14 , wherein the low-E coating and the dielectric coating are configured so that the IG window unit has an LSG value of at least 2.3, and a ΔC value of no greater than 1.5 as viewed from an exterior of a building in which the IG window unit is to be mounted across a range of angles of at least 85 degrees. 
     
     
         18 . The IG window unit of  claim 14 , wherein the low-E coating has a sheet resistance (R s ) of no greater than 2.0 ohms/square. 
     
     
         19 . The IG window unit of  claim 14 , wherein the high index layers comprise an oxide of titanium. 
     
     
         20 . The IG window unit of  claim 14 , wherein the high index layers comprise an oxide of niobium. 
     
     
         21 . The IG window unit of  claim 14 , wherein the low index layers comprise an oxide of silicon. 
     
     
         22 . A coated article for use in a window unit, the coated article comprising:
 at least a first glass substrate;   wherein the first glass substrate supports a low-E coating and an angular reduction dielectric coating on respective opposite major surfaces thereof, respectively;   wherein the low-E coating comprises a plurality of infrared (IR) reflecting layers, wherein at least a first dielectric layer of the low-E coating is provided between at least first and second of the IR reflecting layers;   wherein the angular reduction dielectric coating, which is on a side of the first glass substrate opposite the low-E coating, comprises a plurality of high index and low index layers, wherein at least one high index layer of the angular reduction dielectric coating comprises an oxide of titanium and/or niobium; and   wherein the low-E coating and the angular reduction dielectric coating are configured so that the coated article has a ΔC value of no greater than 3.0 as viewed from an exterior of the coated article across a range of angles of at least 85 degrees from a normal viewing angle which is perpendicular to the coated article, and wherein ΔC is defined as   
       
         
           
             
               
                 Δ 
                 ⁢ 
                 C 
               
               = 
               
                 [ 
                 
                   
                     
                       ( 
                       
                         a 
                         - 
                         
                           a 
                           0 
                         
                       
                       ) 
                     
                     2 
                   
                   + 
                   
                     
                       [ 
                       
                         
                           ( 
                           
                             b 
                             - 
                             
                               b 
                               0 
                             
                           
                           ) 
                         
                         2 
                       
                       ] 
                     
                     
                       1 
                       / 
                       2 
                     
                   
                 
               
             
           
         
         where “a” is an a* color value at the normal viewing angle, and “a o ” is an a* color viewing angle at the off-axis viewing angle, “b” is a b* color value at the normal viewing angle, and “b o ” is a b* color viewing angle at the off-axis viewing angle. 
       
     
     
         23 . The coated article of  claim 22 , wherein the low-E coating has a sheet resistance (R s ) of no greater than 2.0 ohms/square. 
     
     
         24 . The coated article of  claim 22 , wherein the high index layers comprise an oxide of titanium. 
     
     
         25 . The coated article of  claim 22 , wherein the high index layers comprise an oxide of niobium. 
     
     
         26 . The coated article of  claim 22 , wherein the low index layers comprise an oxide of silicon. 
     
     
         27 . An IG window unit comprising the coated article of  claim 22 , wherein the IG window unit further comprises a second glass substrate.