Patent ID: 6297509
Filing Date: 2001-10-02
Classification: G07D

Abstract:
An apparatus for detecting fluorescently and phosphorescently emitted light from sheet material such as papers of value or bank notes, comprising:an illuminating device for illuminating the sheet material with clocked excitation light,at least one sensor for detecting light emitted by the sheet material, anda transport system for transporting the sheet material past the illuminating device and sensor in a transport direction, wherebythe sensor detects an intensity of emitted light in the light phase of the clocked excitation light and an intensity in the dark phase thereof,an evaluation device is provided for deriving an intensity of fluorescently emitted light and an intensity of phosphorescently emitted light from the intensities detected in the light phase and the dark phase of the clocked excitation light,the area of the sheet material illuminated by the illuminating device is a multiple of a desired resolution, andthe sensor detects the intensity of emitted light within, and toward the end (in the transport direction) of, the area of the sheet material illuminated by the illuminating device.