US Patent 7509844 Atomic force microscope technique for minimal tip damage

Methods and apparatus for automatically determining a feedback setpoint for use in operating an atomic force microscope (AFM) are provided. The setpoint may be determined by modulating a feedback setpoint while monitoring for a change in a detector signal. In an effort to avoid tip damage and remain in non-contact, attractive mode during use, a setpoint just above a setpoint corresponding to a detected change in a parameter of the detector signal, such as an abrupt change in phase, may be used to operate the AFM.