FUNCTIONAL FILM AND FORMING METHOD THEREOF, AND BULB AND MANUFACTURE THEREOF

PURPOSE:To allow a metallic oxide multi-layered film to function as the protective film of a light diffusing film, and prevent the light diffusing film from falling off due to separation or the like without the necessity of forming another protective film. CONSTITUTION:A glass base body 12 is immersed in a film forming agent and the thus formed liquid film is dried and, next, it is subjected to a heat treatment in the atmosphere of the order of 500-600 deg.C for forming a light diffusing film 14 that contains fine particles of smoothly turbid titanium oxide. Following this, the base body 12 is soaked into an organic solvent solution containing titanium compound polymer or the like, and then heated, and thereafter heat- treated in the atmosphere of about 500-600 deg.C for forming films 18 of transparent titanium oxide (TiO2) that are high refractive index substances, subsequently, it is put into organic solvent solution containing silicon compound polymer or the like and, after drying, heat-treated in the atmosphere of the order of 500-600 deg.C for forming films 20 of transparent silicon oxide (SiO2) that are low refractive index substances. Similarly, a metallic oxide multi-layered film 16 is laid in a interposing manner in order to obtain a functional film.