Tin oxide overcoat indium tin oxide coatings, coated glazings, and production methods

Abstract

The invention provides transparent conductive coatings based on indium tin oxide. The coating has a tin oxide overcoat. In some embodiments, the coating further includes one or more overcoat films comprising silicon nitride, silicon oxynitride, or silica. The coating and its films have compositions, thicknesses, and properties that simultaneously produce low sheet resistance and high visible transmission, preferably together with neutral color properties and good durability.

What is claimed is: 
     
         1 . A multiple-pane insulating glazing unit having a between-pane space and two opposed external pane surfaces, a desired one of the two external pane surfaces bearing a coating comprising both an indium tin oxide film and a tin oxide film, the tin oxide film being located over the indium tin oxide film. 
     
     
         2 . The multiple-pane insulating glazing unit of  claim 1  wherein the tin oxide film is in contact with the indium tin oxide film. 
     
     
         3 . The multiple-pane insulating glazing unit of  claim 1  wherein the tin oxide film has a thickness of between 90 angstroms and 1,200 angstroms. 
     
     
         4 . The multiple-pane insulating glazing unit of  claim 1  wherein the indium tin oxide film has a thickness of between 100 angstroms and 2,000 angstroms together with a sheet resistance of less than 50 ohms/square. 
     
     
         5 . The multiple-pane insulating glazing unit of  claim 4  wherein said desired one of the two external pane surfaces is defined by a glass pane coated with said coating, said coated glass pane having a monolithic visible transmission of greater than 75%. 
     
     
         6 . The multiple-pane insulating glazing unit of  claim 5  wherein the sheet resistance of the indium tin oxide film is less than 15 ohms/square. 
     
     
         7 . The multiple-pane insulating glazing unit of  claim 1  wherein the coating further includes an oxynitride film, the oxynitride film being located over the tin oxide film. 
     
     
         8 . The multiple-pane insulating glazing unit of  claim 7  wherein the coating further includes a film comprising titanium oxide, the film comprising titanium oxide being located over the oxynitride film. 
     
     
         9 . The multiple-pane insulating glazing unit of  claim 1  wherein the multiple-pane insulating glazing unit includes an internal pane surface bearing a low-emissivity coating that includes at least one film comprising silver, the low-emissivity coating being exposed to the between-pane space, the multiple-pane insulating glazing unit having a U value of less than 0.25 together with a visible transmission of greater than 55%. 
     
     
         10 . A coated pane comprising a glass substrate and a coating on the glass substrate, the coating comprising both an indium tin oxide film and a tin oxide film, the tin oxide film being located further from the glass pane than is the indium tin oxide film, the indium tin oxide film having a thickness of between 100 angstroms and 2,000 angstroms, the tin oxide film having a thickness of between 90 angstroms and 1,200 angstroms, the indium tin oxide film having a sheet resistance of less than 20 ohms/square, and the coated pane having a visible transmission of greater than 75%. 
     
     
         11 . The coated pane of  claim 10  wherein the tin oxide film is in contact with the indium tin oxide film. 
     
     
         12 . The coated pane of  claim 10  wherein all the films of the coating are oxides, nitrides, or oxynitrides. 
     
     
         13 . The coated pane of  claim 10  wherein the visible transmittance is greater than 85%. 
     
     
         14 . The coated pane of  claim 10  wherein the thickness of the tin oxide film is between 200 angstroms and 400 angstroms. 
     
     
         15 . The coated pane of  claim 10  wherein the thickness of the indium tin oxide film is between 1,000 angstroms and 1,600 angstroms and its sheet resistance is less than 15 ohms/square. 
     
     
         16 . The coated pane of  claim 10  wherein the coating further includes an oxynitride film, the oxynitride film being located over the tin oxide film. 
     
     
         17 . The coated pane of  claim 16  wherein the oxynitride film is an exposed outermost film of the coating and has a thickness of between 100 angstroms and 1,300 angstroms. 
     
     
         18 . The coated pane of  claim 16  wherein the coating further includes a film comprising titanium oxide, the film comprising titanium oxide being located over the oxynitride film. 
     
     
         19 . The coated pane of  claim 10  wherein the coating is devoid of a metal layer. 
     
     
         20 . A coated pane comprising a glass substrate and a coating on the glass substrate, the coating comprising both an indium tin oxide film and a tin oxide film, the coating having an emissivity in the range of from 0.25 to 0.55, the tin oxide film being located further from the glass pane than is the indium tin oxide film, the indium tin oxide film having a thickness of greater than 100 Å but less than 1,100 Å, the tin oxide film having a thickness of between 90 angstroms and 1,200 angstroms, the coated pane having a visible transmission of greater than 75%.