In this paper, we report a piezoelectric deformable mirror composed of piezoelectric thin films for low-voltage adaptive optics (AO). A 2-mum-thick piezoelectric Pb(Zr,Ti)O₃ (PZT) film was deposited on a Pt-coated silicon-on-insulator (SOI) substrate, and a diaphragm structure of 15 mm in diameter was fabricated by etching a Si handle wafer. A 19-element unimorph actuator array was produced on the PZT films with an Al reflective layer over the backside of the diaphragm. Measurements of the displacement profile using a laser Doppler vibrometer demonstrated that a large displacement of approximately 1 mum was obtained by applying a voltage of 10 V_pp on one actuator. To examine the application feasibility of the deformable mirror to AO, we reproduced low-order Zernike modes by calculating the voltage on each individual electrode using an influence function matrix. The measurements demonstrated that the deformable mirror could produce the Zernike modes up to the seventh term. Considering the low-voltage actuation as well as the capability for miniaturization of the electrode size, deformable mirrors (DMs) actuated by PZT films are desirable for low-cost AO

This paper proposes a bimorph piezoelectric vibration energy harvester (PVEH) with a flexible 3D meshed-core elastic layer for improving the output power while lowering the resonance frequency. Owing to the high void ratio of the 3D meshed-core structure, the bending stiffness of the cantilever can be lowered. Thus, the deflection of the harvester and the strain in the piezoelectric layer increase. According to vibration tests, the resonance frequency is 15.8% lower and the output power is 68% higher than in the conventional solid-core PVEH. Compared to the solid-core PVEH, the proposed meshed-core PVEH (10 mm × 20 mm × 280 μm) has 1.3 times larger tip deflection and the maximum output power is 24.6 μW under resonance condition at 18.7 Hz and 0.2G acceleration. Hence it can be used as a power supply for low-power-consumption sensor nodes in wireless sensor networks. Graphical Abstract