Design Of Three-dimensional Resonant Trigger Probe System Based On Piezoelectric Film

Recently, as the ultra precision machining and micro machining being applied widely,micromachine, ultra precision optics, MEMS and et al become more and moreminiature, and the traditional micro-nano coordinating measuring machine (CMM) cannot meet the meauring accuracy demand of these micro devices and micro displacement.Therefore, developing new type of micro-nano CMM becomes the new trend. CMM hasbecome a research focus in the field of three-dimensional (3D) micro-nanomeasurement.Due to the difficulty of the development of the3D nano probe, a novel3D resonanttrigger probe has been proposed. This probe can reach nanometer/sub-nanometerresolution in three-dimensions, and its operation principle is different from the presentcontact probes and optical non-contact probes. The probe contacts the sample intraditional tapping-mode in z direction and friction-mode in both x and y directions.The3D resonant trigger probe is constructed by a piece of piezo-electrical PVDF film,two piezo-actuators, an integrated fiber micro-stem and micro-ball tip. The PVDF filmvibrates at its resonant frequency and acts as a sensor. Using the piezoelectric propertyof PVDF film and the high sensitivity of its resonant parameters to the micro-force, theprobe can give3D trigger signal. The3D resonant trigger probe system constructed bythe above probe,3D nano positioning unit, the feedback control module and the signalprocessing circuit. Theoretical model, system construction and property of this novel3Dresonant trigger probe system have been introduced in the paper.Experimental results show that the trigger resolution of3D resonant trigger probesystem could reach sub-nanometer resolution, which is0.12nm in x direction and0.10nm in y direction, while0.12nm in z direction. The3D repeatability error is26nm,36nm and10nm respectively. The results demonstrate the validity of the new type of3Dresonant trigger probe system.