Tuesday, August 05, 2008

US Patent 7406859 - Piezoelectric cantilever rigidity control for AFM


Atomic force microscopes are tools which provide researchers the ability to manipulate and inspect individual atoms, molecules, and nanostructures. These tools usually employ cantilevers having a sharp tip combined with a piezoelectric feedback mechanism to regulate the distance between the tip and a sample. However, when choosing rigid cantilever materials for the AFM some sensitivity is lost in the manipulation/detection while less rigid cantilevers are more difficult to control. This patent from Michigan State University teaches a controlled rigidity piezoelectric cantilever which attempts to optimize cantilever performance between rigidity and flexibility. Claim 1 reads:

1. A nanomanipulation system for performing nanomanipulation operations in relation to a sample surface, comprising:

an atomic force microscope having a probe for performing nanomanipulation operations on the sample surface, where the probe includes a cantilever having a layer of piezoelectric material;

a position detector configured to ascertain deformation of the cantilever during a nanomanipulation operation;

an active probe controller adapted to receive data indicative of the deformation from the position detector and implements a control scheme based on the deformation data which maintains rigidity of the cantilever during the nanomanipulation operation, wherein the control scheme produces a control signal that is applied to the piezoelectric material of the cantilever.