The IMGC calibration set-up for microdisplacement actuators

In the calibration of piezo-capacitive displacement actuators, use is made of an interferometric set-up with sub-nanometric resolution. In order to minimise the periodic non-linearity effect of the interferometer, accurate h-steps are obtained from a computer-based loop control of the out-of-phase between the reference and the measuring signal of the interferometer. Experimental results show a standard uncertainty of about 1 nm + 0.7 . 10(-4) L/mu m.