A micro electromagnetically-driven scanner by 2-DOF second-order resonance to extend scanning scale for ultra-thin single-fiber endoscope application

This paper presents an electromagnetically-driven single-fiber scanner utilizing 2 degree-of-freedom (DOF) second-order resonance to realize a larger field scanning scale in narrow space of the human body. We design a reasonable 2-DOF system structure including fiber, magnet and weight, which can conveniently execute high-order resonance modal to extend the scanning angle in the limited dimensional tube of the ultra-thin endoscope. A low-cost flexible microcoil embedded in polyimide film is also fabricated to drive the fiber-magnet-weight 2-DOF system to vibrate. The magnetic field distributions of the microcoil with different structural parameters are simulated. The test result shows that the scanner with the second-order resonance model successfully realizes 9.47° scanning scale, which is much larger than that (2.98°) obtained at the traditional first-order resonance model. Finally, the scanning locus of fiber tip in the scanner probe has been measured in xoy-plane by standard position sensitive detector (PSD).