A SICM probe-sample distance control method and system

Abstract

The invention relates to a probe sample distance control method and system for an SICM (scanning ion conductance microscope). The method includes the following steps that: a falling edge compensationfunction model is established before scanning is carried out; the line scanning height of a previous pixel is recorded during an imaging process and is adopted as the predicted value of a current to-be-scanned line; the difference value of the real-time position of a probe and predicted height, adopted as a parameter, is inputted to the falling edge compensation function model, so that a falling edge compensation coefficient can be obtained; and rising edge and falling edge judgment is carried out, an obtained current deviation is updated; the new current deviation is fed back to a controller,and the controller controls a piezoelectric ceramic to move up and down, so that the probe is always kept at a constant distance from a sample. The system includes an approximation curve module, a falling edge compensation function model building module, a line prediction module, and a feedback control module. With the method and system of the invention adopted, the problem of the difference of the deviation of the rising edge and falling edge of the sample caused by the nonlinearity of an approximation curve can be solved, so that the falling edge blurring of SICM imaging can be eliminated.Compared with conventional PID control, the method and system are more accurate in imaging.

Description

technical field [0001] The invention relates to the technical field of scanning ion conductance microscope (SICM) imaging, in particular to an adaptive control method and system for the distance between a probe and a sample during SICM imaging. Background technique [0002] Scanning ion conductance microscope (SICM) is a scanning probe microscope widely used in biology, medicine, chemistry, materials and other fields. Compared with traditional optical microscope, it has higher resolution. The microscope is limited by the optical diffraction limit, and the resolution cannot reach below 200nm, while the scanning probe microscope uses the interaction between its probe and the sample surface as the imaging basis, and is not affected by the optical diffraction limit, and the resolution can reach several nanometers or tens of nanometers. Nano; Compared with other scanning probe microscopes, SICM is characterized by the non-destructive observation of living cells under physiologica...

AI Technical Summary

Problems solved by technology

Due to the non-linearity of the approximation curve, for the same height change, the current deviation as the feedback value is larger on the rising edge of the sample height, and the current deviation is smaller on the falling edge. If the same PID parameters are used at this time, the Different control values ​​are generated, so that the speed of the probe tracking is different. The change of the height of the sample can be quickly tracked on the rising edge, but it takes longer to complete the tracking of the height on the falling edge, resulting in a tailing phenomenon.

Images