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 (≈ 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 ∘ ( ≈ 42 ∘ total optical scan angle (TOSA)) at drive levels of 8–10 V pp and 60–80 mA ( ≈ 0.5 z − 0.8 W ). 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 ∘ 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.