POSITION DETERMINATION DEVICE USING OPTICAL SCANNING OF MEASUREMENT SCALE, AND GUIDING SYSTEM WITH BODIES MOVABLE RELATIVE TO EACH OTHER AND POSITION DETERMINATION DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a position determination device having a compact measurement head in a simple structure.

SOLUTION: The position determination device comprises a measurement scale 10 having markers 11, 12, and a measurement head 21 movable relative to the measurement scale 10. The measurement head 21 comprises a telecentric optical system 30 for generating an image of the measurement scale 10, and a sensor 40 for capturing this image and providing a signal for a position determination of the measurement head 21. The telecentric optical system 30 includes a first lens element 33 including an optical axis 34, and an aperture 35 disposed at a focus F1 facing an opposite side of the measurement scale 10 of the lens element 33. The telecentric optical system 30 also includes a block 31 integrated with the lens element 33, a first area 32.1 of a surface 32 of the block 31 forms a surface of the lens element 33, and the aperture is disposed at a second area 32.2 of the surface 32 and is realized as a first mirror surface 35 inclined at an acute angle with respect to the optical axis 34.

COPYRIGHT: (C)2012,JPO&INPIT