Heat-treatment convertible coated glass and method of converting same

Abstract

A high performance, durable sputter coated, heat-treatable glass which after heat-treatment exhibits about 76% or more visible transmittance, a hemispherical emissivity (E.sub.h) of about 0.16 or less, and a normal emissivity (E.sub.n) of about 0.12 or less is formed by sputter coating a layer system on a glass substrate which includes an undercoat and overcoat of Si.sub.3 N.sub.4, a silver layer, and two nickel or nichrome layers on opposite sides of the silver layer, and wherein the lower nickel-based layer is about three times as thick as the other nickel based layer. The increased thickness of the lower nickel-based layer allows the coated glass article to be both heat-treatable, and "low-E" after the heat-treatment. This allows matching with other known glasses in the family of layer components by way of the heat-treatment process. The layer system employed allows, even if not matchable to another glass, for the sputter coating operation to include the coating of other members of the family of coating without change of targets, efficient use of the coater targets that exist, and minimal operational changes during production.

Dependencies are inferred from the claim text.