Abstract: A method for manufacturing an airtight vessel seals an evacuation tube after evacuating the inside of the vessel using the evacuation tube. A getter previously disposed in the vessel is activated followed by fusing a part of the evacuation tube to seal the vessel while heating the vessel.

Abstract: In formation of thin films on both surfaces of a substrate such as a lens or the like, a pair of cluster beam evaporation sources are provided in mutually separate manner in a film forming chamber. The substrate is disposed between the pair of cluster beam evaporation sources. The cluster beam evaporation source includes a crucible which is arranged to be inclined toward the substrate, or which has a nozzle on a lateral face opposed to the substrate.

Abstract: In a method of manufacturing a thin film, evaporated particles are generated by a vapor source and are clustered. The clustered evaporated particles are deposited onto a substrate in a vacuum atmosphere without ionizing the particles. A partial pressure of water in the vacuum atmoshpere is controlled to not more than 5.times.10.sup.-6 Torr. A temperature of the substrate is maintained to be 150.degree. C. or lower. A film according to this method has a high adhesion characteristics and a high mechanical strength without heating the substrate to a high temperature and without damaging the substrate by ions.