Coated article with low-E coating including IR reflecting layer(s) and corresponding method
View Patent ↗A coated article is provided that may be heat treated in certain example embodiments. A coating of the coated article includes a zinc oxide inclusive layer located over and contacting a contact layer that is in contact with an infrared (IR) reflecting layer of a material such as silver. It has been found that the use of such a zinc oxide inclusive layer results in improved thermal stability upon heat treatment, increased visible transmission, and/or lower sheet resistance (R s ).
1. A heat treated coated article comprising a coating supported by a glass substrate, the coating comprising:
a first dielectric layer comprising zinc oxide from 40-150 Å thick;
a first infrared (IR) reflecting layer comprising silver located over at least the first dielectric layer comprising zinc oxide;
a second layer comprising zinc oxide located over at least the first IR reflecting layer and the first dielectric layer;
a second IR reflecting layer comprising silver located over and contacting the second layer comprising zinc oxide, the second IR reflecting layer comprising silver having a thickness greater than the first IR reflecting layer comprising silver;
a layer consisting essentially of an oxide of NiCr located over and contacting the second IR reflecting layer;
a third layer comprising zinc oxide located over and contacting the layer consisting essentially of the oxide of NiCr, the third layer comprising zinc oxide being 40-150 Å thick, the third layer comprising zinc oxide being thicker than the second layer comprising zinc oxide, and the layer consisting essentially of the oxide of NiCr being 20-45 Å thick;
another dielectric layer comprising tin oxide from 40-200 Å thick located over at least the third layer comprising zinc oxide in the heat treated coated article; and
when measured monolithically following heat treatment the coated article has a visible transmission of at least 80%, a sheet resistance (R s ) of less than or equal to 2.5 ohms/square, and a normal emissivity (E) of less than or equal to about 0.04.
2. The coated article of claim 1 , wherein at least one of the first and second layers comprising zinc oxide further comprising aluminum.
3. The coated article of claim 1 , further comprising a layer which comprises silicon nitride provided between the glass substrate and the first dielectric layer comprising zinc oxide.
4. The coated article of claim 1 further comprising another dielectric layer comprising silicon nitride located over and contacting the another layer comprising tin oxide.
5. The coated article of claim 1 , further comprising a layer comprising tin oxide located between the first IR reflecting layer and the second layer comprising zinc oxide.
6. The coated article of claim 3 , wherein the dielectric layer comprising silicon nitride is Si-rich so as to be represented by Si x N y , where x/y is from 0.8 to 1.4.
7. The coated article of claim 1 , wherein when measured monolithically following heat treatment the coated article has a visible transmission of at least 81% and a sheet resistance (R s ) of less than or equal to 2.1 ohms/square.
8. The coated article of claim 1 , wherein the coated article comprises a laminate including said substrate which supports the coating and is heat treated and that is laminated to another heat treated glass substrate, the laminate having a visible transmission of at least 76% and a sheet resistance (R s ) of less than or equal to 3.0 ohms/square.
9. The coated article of claim 1 , wherein the coated article comprises a laminate including said substrate which supports the coating and is heat treated and that is laminated to another heat treated glass substrate, the laminate having a visible transmission of at least 77% and a sheet resistance (R s ) of less than or equal to 2.5 ohms/square.
10. The coated article of claim 1 , wherein the coated article comprises a laminate including said substrate which supports the coating and is heat treated and that is laminated to another heat treated glass substrate, the laminate having a visible transmission of at least 78% and a sheet resistance (R s ) of less than or equal to 2.5 ohms/square.