AFTERGLOW ILLUMINANT AND METHOD FOR MANUFACTURING THE SAME, AFTERGLOW LUMINESCENT INK COMPOSITION, AND PRINTED MATTER FOR AUTHENTICITY DISCRIMINATION

摘要

PROBLEM TO BE SOLVED: To provide an afterglow illuminant featuring in that a person informed of the characteristics of counterfeit prevention technology imparted to the illuminant can discriminate authenticity with a simple tool, while a person not informed hardly notices the illuminant.SOLUTION: The afterglow illuminant is expressed by chemical formula of (MBaEu)(a+k)O-(MgMn)bO-c(SiO), where M represents Ca (calcium) or Sr (strontium); k is 0 or 0.3; and a, b, c, x and y satisfy 2≤a≤3.5, 0.75≤b≤2, 2.75c≤3, 0.01≤x≤0.2 and 0.02≤y≤0.4, respectively. A luminescent color of fluorescent light during excitation light irradiation is different from a luminescent color of afterglow after the excitation light stops; and an afterglow time after excitation light stops is from 2 ms to 5 s.