Measuring Method of Piezo-element Displacement Characteristics as Nano-meter Moving Means.

A measuring method using a newly developed laser diode probe for dynamic and static nanodisplacement characteristics of a ceramic piezo-element was studied. A beam from the probe is exposed in focus at the surface of the sample and the reflected beam is detected. The probe, being applicable to a rather rough surface of a material, can read nano-displacements by detecting the diffraction signal of the reflected beam. A soft ceramic material, PCM-33A (Pb Mg Nb Ti Zr0), 2mm thich 31×15 mm was suspended at the center by needles and the LE and TE were measured. The piezo-electric constants obtained by this method applying DC pulses are d31=410×10-12m/V /and d33=1300×10-12m/V, which are about twice those by the conventional electric method. Large resonance peaks at 47kHz for 31mm LE and 107kHz for 15mm LE are measured showing a complete coinsidence to those obtained by the conventional electrical measurement method. This direct displacement measurement method may become usefull to measure and describe the mechanical displacement characteristics of a piezo-element as mechanical moving means.