Atomic force microscopy data storage system with tracking servo from lateral force-sensing cantilever

摘要

An atomic force microscope (AFM) based data storage disk drive uses a cantilever structure that provides independent detection of vertical and lateral motion of the AFM tip as a track with data marks moves past the tip. The vertical detection of the tip deflection toward and away from the disk surface is used for data detection of the data marks that form the tracks. The lateral detection of the tip deflection in a direction generally parallel to the plane of the disk surface is used as the input signal to a tracking servo control system to maintain the tip on a data track. The cantilever structure includes a base connected to the disk drive actuator, a beam made up of a plurality of ribs that have their fixed ends connected to the base, and a probe connected to the free ends of the ribs. The beam ribs have piezoresistors connected to electrical circuitry that detects a resistance change as the ribs are bent laterally. The probe includes the AFM tip located at its free end and piezoresistors connected to electrical circuitry that detects a resistance change as the probe is bent vertically. The data tracks are a series of data marks in the form of pits or bumps separated by portions of the disk surface that serve as lands. Alternatively, the data tracks are formed as continuous grooves in the disk surface with the data pits or bumps located at the bottoms of the grooves.