History of the development and industrial production of low thermal emissivity coatings for high heat insulating glass units

Low-emissivity (low-E) coatings play a dominate role in high heat insulating multiple glass units with which an essential part of heat energy can be saved in buildings. With such coatings as the main part, and to a lesser part with low thermal conductive filling gases of the units' interspaces, their heat transmittance can be reduced from 6.0 W/m(2) K for a single glazing-still glazed to a high degree-to 0.4 W/m(2) K for a triple insulating glass unit. This astonishing development is regarded as one of the most important innovations of the flat glass industry in the past century. The roots of low-E coatings in the 1960s, their startup for production in the 1970s, and, most important, further development steps accompanied by, and partly also codesigned actively by the author, are depicted. (c) 2008 Optical Society of America.