Patent attributes
A lithographic apparatus includes a displacement measuring system configured to measure the position of a substrate table in at least three degrees of freedom. The displacement measuring system includes a first x-sensor configured to measure the position of the substrate table in a first direction and a first and a second y-sensor configured to measure the position of the substrate table in a second direction. Said displacement measuring system further comprises a second x-sensor. The first and second x-sensor and first and second y-sensors are encoder type sensors configured to measure the position of each of the sensors with respect to at least one grid plate. The displacement measuring system is configured to selectively use, depending on the position of the substrate table, three of the first and second x-sensors and the first and second y-sensors to determine the position of the substrate table in three degrees of freedom.
