A time indicator for use as a security badge. The badge includes a four-layer front part and a two-layer rear part. The front part has, overlying each other, a transparent front support layer with a front print display surface, an adhesive and ink display layer with a front ink display surface, an optical barrier layer; and an adhesive and ink dissolver layer. The rear part has, overlaying each other, an ink film layer and a backup member layer. Upon issue of the badge, a release sheet is peeled off the ink film layer, and the front part is overlaid and pressed down upon the rear part, with the adhesive and ink dissolver layer and the ink film layer forming an assembly joint therebetween. The time interval then begins and the ink migrates from the ink film layer, in series, through the assembly joint, the ink dissolver layer, the optical barrier layer, the adhesive and ink display layer to the front ink display surface, where it forms expiration notice words and diagonal voiding bars after expiration to the time interval.