SCANNING PROBE MICROSCOPE

摘要

PROBLEM TO BE SOLVED: To provide a scanning probe microscope of the type of oscillating a cantilever capable of performing accurate measurement while preventing a soft sample such as a biological sample from being damaged as much as possible. SOLUTION: A Z control circuit 150 controls a Z drive circuit for displacing a scanner of the scanning probe microscope in a Z-direction. The Z control circuit 150 comprises a subtractor 152 for subtracting a cantilever amplitude signal from a control reference value; a PID circuit 154 for amplifying a deviation signal outputted from the subtractor 152; and a correction gain circuit 156 for correcting the gain of the deviation signal by the PID circuit 154. The correction gain circuit 156 does not amplify the deviation signal when the deviation signal is positive and amplifies the deviation signal (by a gain larger than 1) when the deviation signal is negative. In other words, the correction gain circuit 156 heightens the gain of closed loop control when the deviation signal outputted from the subtractor 152 is negative. COPYRIGHT: (C)2004,JPO