A self-tuning resonance-locking method for polymer MEMS microscanners

Abstract

This study presents a self-tuning optical MEMS microscanner based on a low-cost polyimide structure integrated with a piezoresistive feedback mechanism. The system automatically detects and tracks the torsional resonance frequency (approximate to 81 Hz), compensating for spring softening effects that otherwise degrade scan performance. A custom frequency sweep algorithm, combined with a closed-loop control, dynamically adjusts the actuation signal to maintain resonance-locked operation, enabling stable mechanical scan angles of 10-12 degrees ( approximate to 42 degrees total optical scan angle (TOSA)) at drive levels of 8-10 Vpp and 60-80 mA ( approximate to 0.5z-0.8W). This approach ensures stable displacement and total optical scan angle over time, even under frequency drift. In high-power characterization sweeps, the device demonstrates optical scan angles up to 100 degrees TOSA. The proposed architecture offers a practical and scalable solution for energy-efficient, high-resolution optical scanning using inexpensive and easily manufacturable polymer-based MEMS devices.