圧電微小超音波トランスデューサによるマルチモーダル指紋・静脈認証センサーの開発

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1.Designed, fabricated and demonstrated new structures for pMUT and pMUT array towards near-distance ultrasonic imaging application based on Monocrystalline-PZT based thin film. Firstly, an island-shaped and an annular-shaped structure was designed for single pMUT element. The proposed structures were optimized through FEM simulation and the best design parameters were confirmed. Then, the research of the fabrication process for 2-D pMUT array was completed. A kind of row-column addressed 2-dimensional piezoelectric micromachined ultrasonic transducer (pMUT) array based on the Mono-PZT based thin film was successfully fabricated.2.Characterization of the performance of fabricated pMUT and array. he pMUT can provide 4.8 kPa sound pressure at 5V driving voltage and 0.016 pC/KPa as output sensitivity and receiving sensitivity at resonance, and a -3 dB bandwidth around 3.5 MHz, respectively.3.A platform and corresponding circuit in order to evaluate the beamforming and imaging ability of the fabricated 2-D pMUT array was prepared. The imaging program based on the Tof (time of flight) was also designed and prepared.4.The ultrasonic image was demonstrated via the ToF mode with ultrasonic burst waves by the fabricated pMUT array at a low transmitting voltage (5V). The ultrasonic imaging along the depth direction can shows double layer including fingerprint and vessel structure clearly. The image along the lateral direction can clearly show the surface structure of the observed object.