A white film for a reflecting structure for surface light sources, which contains voids inside it and has a light stabilizer-containing coating film formed on at least one surface of it, is aged little with time and its brightness lowers little even when used for a long time. In some embodiments, the modular wall units have water dispensers. 01 microns to about 10 microns, which comprises a biodegradable solid hydrophobic core and a bioadhesivemucoadhesive positively charged surface. The detection unit detects that a reference position disposed on the photosensitive member has reached a predetermined position.