Afterglow luminescent material and method for producing the same, afterglow luminescent ink composition, and authenticity printed matter

摘要

PPROBLEM TO BE SOLVED: To provide an illuminant with afterglow properties having characteristics which allow the people with knowledge of characteristics of an imparted forgery prevention technique to perform authenticity judgment using simple equipment, but which are hardly noticed by the people without the knowledge. PSOLUTION: The illuminant with afterglow properties is represented by (MSBk/SBBaSBa-x/SBEuSBx/SB)(a+k)O-(MgSBb-y/SBMnSBy/SB)bO-c(SiOSB2/SB), wherein M is Ca (calcium) or Sr (strontium); k is 0 or 0.3; a is 2a3.5, b is 0.75b2, c is 2.75c3, x is 0.01x0.2, and y is 0.02y0.4. The luminescent color of fluorescence during excitation light irradiation is different from the luminescent color of afterglow after the excitation light stops. The afterglow time after the excitation light stops is 2 ms to 5 s. PCOPYRIGHT: (C)2011,JPO&INPIT