A CMUT-based finger-mounted 3D ultrasound probe

Developing 2D array-based systems for 3D imaging is overall more challenging due to the complexity in addressing the transducer elements. The Row-Column (RC) scheme results in a significant reduction in electrical leads at a reasonable cost in imaging quality. This paper presents imaging analysis on RC beamforming and provides evidence on why an RC-based Capacitive Micromachined Ultrasonic Transducer (RC CMUT) array is suitable for mounting on the finger-tip for close-up imaging. The prototype can be fitted over a finger and be used for scanning a small targeted volume. The front-end electronics are also designed so that the device can be hands-free and be attached to the back of the hand. The simulation and experiment shows that the calculated scanning volume is highly limited by natural focusing. For a 4.8mm by 4.8mm, 5.9MHz, 32×32 elements RC CMUT array, the calculated -6dB lateral resolution ranges from 0.3mm to 1mm within a 10mm depth. The effective scanning volume, given a 1mm resolution threshold, is approximately 4.5mm by 4.5mm by 10mm.