摘要 |
Apparatus for measuring displacements on an object to nanometer accuracy, particularly for use in fabricating modern signal processing components. This coprises a radio frequency source for a primary electrical signal (50), a transducer (24) for generating an intermediate signal of lesser wavelength at least partly therefrom, a phase shifting means (56) interactive with the immediate signal and associated with the object in such a way that a displacement of the object causes the phase shifting means (56) to change the path length of the intermediate signal by an amount directly related to the displacement, a phase transference means (60) for generating a secondary electrical signal using, at least partly, the intermediate signal so that the phase of the intermediate signal is transferred to the secondary signal, and a phase detector (62) for measuring the change of phase of the secondary signal relative to the primary on displacement of the object. <IMAGE> |