PURPOSE: To measure water-insoluble contamination on a surface, by uniformly blowing the aqueous solution of fluorescent dye on the surface of a glass part, and thereafter regarding a part which does not emit fluorescent light as the contaminated part when ultraviolet rays are projected on the dye applied surface in a dark place.
CONSTITUTION: Aqueous solution 1 of fluorescent dye is blown on a glass panel 3 of, e.g., a picture tube, which is a sample to be checked, in droplets 1a. Ultraviolet rays are projected on the panel 3, on which the aqueous solution of the fluorescent dye is blown, in a dark room 4 from an ultraviolet lamp 5, and the panel is observed. At this time an oil-contaminated part 6 of the panel 3 does not emit fluorescent light and looks dark. The droplets of the solution of the fluorescent dye are attached on a clean part 7, and the part 7 emits the fluorescent light and looks bright. Thus, the entire shape of the oil- contaminated part of the surface of the glass part is clearly confirmed without destruction.
EZAWA MASAYOSHI
WAKANA SHIGERU
MATSUMOTO TOSHIYUKI
HITACHI DEVICE ENG