Patent ID: 9557347
Date: 2017-01-31
CPC Classifications: B82Y,G01Q

Claim:
1. A scanning probe microscope comprising: a probe that is mechanically responsive to a driving force, a signal generator for providing a drive signal to an actuator that generates the driving force, the drive signal being such as to cause the actuator to move the probe repeatedly towards and away from a sample; an interferometer arranged to output a height signal indicative of a path difference between light reflected from the probe and a height reference beam; image processing apparatus that is arranged to use the height signal to form an image of the sample; and signal processing apparatus arranged to monitor the probe as the probe approaches a sample and to detect a surface position at which the probe interacts with the sample; wherein in response to detection of the surface position the signal processing apparatus prompts the signal generator to modify the drive signal; and wherein the signal processing apparatus prompts the signal generator to modify the drive signal immediately after detection of the surface position, or soon after detection of the surface position and before the next repeat of the motion of the probe towards and away from the sample, in order to retract the probe away from the sample.