Patent ID: 6172745
Filing Date: 2001-01-09
Classification: G01D,G07D

Abstract:
A device for sensing the optical characteristics of a document moving relative to the device in a transport path, said device comprising:a plurality of groups of light sources, each said group generating light of a different wavelength and the light sources of each said group being spaced across a light-generating area optically coupled to said transport path by a first light path;a plurality of light detectors spaced across a light-detecting area optically coupled to said transport path by a second light path different to said first light path, said light detectors being arranged to receive light from a plurality of discrete detection areas on said transport path; anda unitary light guide defining at least part of said first light path, said light guide having a light-receiving end, reflective sides, and a light-emitting end,wherein the said light generating area is optically coupled to the light-receiving end of the light guide, the light guide conveying light generated by each of said light sources towards said transport path.