Industrial production of coated glass: Future trends for expanding needs

Since decades, electroless plating has been used to produce mirrors. This extremely cheap process is now challenged by vacuum deposition and CVD (chemical vapor deposition) coating. In the fifties, architects began to design glass buildings and asked their suppliers for thermal protective products. Vacuum evaporation deposition, used for optics, was adapted for bigger surfaces. Then, boosted by increasing demand, two processes emerged for low cost production: direct pyrolysis on the float ribbon and magnetron sputtering. Today, heat regulating layers represent, by far, the biggest market in terms of sales and global potential. Production has reached many tens of million square meters per year. Sputtering and pyrolysis are still in competition. Both techniques made impressive progress. Sputtering lines reached capacities of many millions square meters per year handling automatically jumbo plates. During the same time, pyrolysis proposed multilayered structures and improved greatly deposition speed and uniformity. As the market continues to expand, new improvements are expected: for sputtering, higher speeds and the possibility of using non conductive targets, for pyrolysis, a decrease of the raw materials costs and an improvement in deposition yield. Other markets are emerging. They represent much smaller quantities but can take advantage of the improvement of the mass production technologies. In turn, as they need a high level of quality, they bring the opportunity of studying new deposition techniques and push the technology forward: transparent conductive coatings for displays, anti-solar coatings for automotive glazing, anti-reflective coatings, photovoltaics. Today, for these products low-pressure processes are used. When the market becomes larger, atmospheric CVD will be competitive. (C) 1997 Elsevier Science B.V.