OPTICAL TRACKING AND POSITION DETERMINATION FOR DETECTION METHODS AND SYSTEMS

摘要

A tracking system (106) is described for tracking areas on a substrate (104) using an irradiation beam. The irradiation beam typically has an irradiation beam projection (202) on the substrate (104) whereby at least one dimension of the irradiation beam projection (202) is substantially larger than a wavelength of the irradiation beam. The tracking system (106) typically comprises a detecting means (108) adapted for detecting a variation of an optical characteristic of at least part of the irradiation beam induced by interaction with different regions (204, 206) of the substrate having different irradiation modulating properties, for locating said irradiation beam with respect to said substrate (104). The tracking system typically is adapted to cooperate with a substrate. The invention also relates to a position determination system for obtaining position related information from a modulation of the irradiation beam induced by the substrate, a corresponding method and substrates for use therewith.