Laser interferometer has reference beam path and mirror which are arranged linearly along movement direction of slider

摘要

Reference beam path (24) and optical path (22) having variable length are extended along movement direction of slider (16). A mirror (21) and a microscope (4) that detects markings on measurement scale (5) are fixed on bridge structure (3) of base (1). The mirror and reference beam path are arranged linearly along movement direction of slider.