Optical encoder for determining the position of two parts that are movable relative to one another in two directions of movement

摘要

The device has scanning systems (20.1-20.3) for scanning a measuring graduation (10) and connected to two objects e.g. semiconductor manufacturing equipment components. The scanning systems determine direction of displacement of the objects along a lateral shift direction and a vertical shift direction of the objects. The measuring graduation comprises a two-dimensional cross lattice. The scanning systems are in non-collinear arrangement to each other to detect movement of the objects in all six spatial degrees of freedom (X, Y, Rz) from linked position values of the scanning systems.