Optical interferometry method for measuring objects

摘要

The method process uses a split beam. One part-beam passes straight to a convergence lens (3) held in a drive device (8) and to the object being measured (4), mounted in another drive (5). The other is directed at right angles to a mirror (6) in a third drive (7) where it is phase-modulated to reflect a reference signal. The reflected signal beam from the object is conducted back to a receiver (10) for comparison and conversion to a digital signal for processing in a PC (13). The phase refraction or double refraction and the thickness of the object can be measured simultaneously, as can phase and group refraction. In one process the convergence lens is held stationary while object and reference mirror are shifted on the optical axis. In the other the object is stationary and lens and mirror are moved. The drives (5,7,8) are moved by a stage controller (14) acting on the PC signal.