Airborne ultrasound focusing aperture with binary amplitude mask over planar ultrasound emissions

Phased arrays of airborne ultrasound transducers are widely utilized as a key technology to achieve mid-air convergence intense ultrasound, which is applied variety systems, such contactless tactile presentation, acoustic-levitation and its application, mid-air-flow acceleration, etc. However, it requires considerably precise phase control with temporally severe synchronization between elements, leads difficulty in scaling up the entire system beyond tabletop size most current application systems. Here, we propose much simpler easier scaling-up method convergence, where binary amplitude mask that serves Fresnel Zone Plate (FZP) placed on planar in-phase sources. We experimentally demonstrate FZP-based focusing achieved spatial resolution comparable conventional methods, based use phase-controlled transducers. The foci created using FZPs sufficiently for scenarios currently practical use. also determine favorable side effects our suppressing grating lobes, inevitable phase-controlling method. sources both readily implemented inexpensive ingredients components. result study contributes upsizing dimensions convergent field successfully generated. Accordingly, unprecedented target room workspace will be possible.