Electronic spacing regulation circuit for resonating test probe - provides piezoelectric position adjustment dependent on phase difference between detected oscillation and reference oscillation

摘要

The circuit is used for controlling the relative spacing between the point of a resonating test probe and an examined surface. The oscillation circuit uses a piezoelectric actuator (6) for sensing the test probe in the direction perpendicular to the surface and a deflection sensor (3) monitoring the oscillating deflection of the probe, with the oscillation signal compared with a reference oscillator signal via a phase detector (9). A further piezoelectric actuator (10) adjusts the position of the probe perpendicular to the surface in dependence on the output signal of the phase detector. USE/ADVANTAGE - For raster scanning microscope or acoustic near-field microscope for maintaining instant spacing of probe tip from examined surface. Simplified circuit.