Original Publication Date: 1987-Dec-01
Included in the Prior Art Database: 2005-Feb-02
Three spindle drives 1, 2 and 3 act on a table 4 which is freely movable in the Z-plane. Table shifting in one coordinate is effected by two spindle drives 1 and 2, arranged in parallel, and in the other coordinate by one spindle drive 3. Laser interferometer heads 5, 6 and 7 are aligned with the spindle axes of spindle drives 1, 2 and 3, respectively. In each coordinate direction, table 4 is fitted with plane mirrors 8 and 9. These mirrors interact with the laser interferometer heads 5, 6 and 7. The spindles of the spindle drives are guided at table 4 in play-free guides 10 and 11 extending transversely to their longitudinal axes.