TRANSPARENT INORGANIC MATERIAL WHICH CAN FORM HETEROGENEOUS PART IN OPTIONAL SHAPE SHOWING BEHAVIOR DIFFERENT FROM SURROUNDINGS WHEN IRRADIATED WITH ULTRAVIOLET RAY, AND ITS PRODUCTION METHOD

摘要

PROBLEM TO BE SOLVED: To provide a display material which can make an image existing as a heterogeneous part formed by being irradiated with pulse laser beams very narrow in width actually in a transparent material unable to indicate the image directly visible. SOLUTION: By exciting a specimen piece including the heterogeneous part by ultraviolet rays, a behavior different from the surroundings of the heterogeneous part, for example the generation of fluorescence, is made to occur in the heterogeneous part so that the shape of the heterogeneous part is made visible. By moving the focus of the ultraviolet rays according to a prescribed pattern, an optional image, which can not be recognized directly by an outsider but is indicated for the person concerned as required, can be recorded in a visible form.