DETERMINATION OF LOW-VOLTAGE ACTUATOR DISPLACEMENTS IN DC AND AC ELECTRIC-FIELDS USING AN OPTICAL INTERFEROMETER

Multilayer low-voltage (< 40 V) actuators can be used in diverse new micromovement applications for which sophisticated computer-controlled high-stability power sources with good frequency response and dynamic range are available. For the purpose of testing these demanding actuators in both d.c. and a.c. electric fields (up to tens of kHz and with different waveforms), an out-of-contact optical silicon chip Michelson interferometer system is utilized and later developed for nanometre-scale movements. The whole integrated sensor head (GaAs laser, photodetectors and fixed mirror configuration on a silicon chip), together with specially designed optics, mechanics and registration hard/software, also enables the determination of three-dimensional displacement distributions of an actuator.