SENSOR DEVICE FOR DETECTING TARGET PARTICLES BY FRUSTRATED TOTAL INTERNAL REFLECTION

摘要

The invention relates to an optical sensor device (100) for detecting target particles (1) at a contact surface (12) of a carrier (11), said sensor device comprising a light source (21, 22) for emitting an input light beam (Ll) into the carrier (11) such that it is totally internally reflected and partially scattered by target particles (1) at the contact surface (12) into an output light beam (L2). The sensor device further comprises an optical system (30) for directing said output light beam (L2) onto a light detector (50), wherein a filter (32) in the optical system (30) suppresses the components (L2d) of totally internally reflected light. The detector therefore primarily measures the fraction of scattered light (L2s).