Abstract: In order to reduce or prevent absorption of water in the adhesive of a panel comprising at least one photovoltaic cell located between a transparent sheet and a second sheet bonded together using an adhesive material, the invention provides that another material is applied at least in part between the sheets to form a moisture barrier which surrounds the cell(s) and the adhesive.The preferred adhesive material is polyvinyl butyral, and the preferred barrier forming material is selected from neoprene based adhesives, polysulphide adhesives and polyvinylidene chloride. When the latter is used a second barrier forming material such as polysulphide adhesive is preferably interposed between the adhesive and the polyvinylidene chloride.

Abstract: A method of manufacturing a hermetically sealed envelope comprising assembling envelope-forming components of which at least one is a vitreous wall forming component wherein the or each vitreous component is metallized along a zone where it is to be bonded by solder to form a sealing joint. Such sealing is effected while the assembly 13 of envelope-forming components is within a hermetically sealable chamber 1 e.g. using heating devices 11, 12. The chamber may be evacuated via exhaust port 7 and valve 9 and optionally filled with a gas other than air via inlet port 4 and valve 6.

Abstract: A laminated glazing pane comprised of at least two sheets of vitreous material joined together by an intervening layer of plastic material given improved sound attenuation properties by constructing the pane in such a manner that its base frequency (f) is between 0.70 and 0.97 times its theoretical base frequency (f.sub.0).