Actively Reconfigurable Segmented Spatial Sound Modulators

Abstract

High‐quality acousto‐holographic patterns and images, integral to applications like 3D displays, acoustophoresis, and midair haptics, require precise distribution of ultrasound waves to achieve. Essential tools for this task are spatial sound modulators (SSMs), which control constituent elements to enable dynamic distribution of sound pressure. However, current ultrasonic SSMs face limitations due to high costs and the intricate actuation of numerous small, closely spaced units. This study introduces “segmented SSMs,” novel devices that combine traditional acoustic metasurface pixel units into custom‐shaped segmented elements. These segmented SSMs reduce actuation costs and complexity while retaining pressure distribution quality. This approach includes a custom phase agglomeration algorithm (PAA), that offers a hierarchy of potential segmentation solutions for user selection. An SSM fabrication method is detailed using off‐the‐shelf 3D printers and bespoke control electronics, completing an end‐to‐end methodology from conception to realization. This approach is validated with two prototype SSM devices that focus sound waves and levitate polystyrene beads using dynamic segmented elements. Further enhancements to the technique are explored through hybrid SSM devices with both static and dynamic elements. The pipeline facilitates efficient SSM construction across diverse applications and invites the inception of future devices with varying sizes, uses, and actuation mechanisms.

Multilateral Sound Manipulation Using Magnetically Tunable Apertures

“…The proposed acoustic device is easy to replicate, uses easily accessible and low-cost materials for fabrication, and is applicable for implementation on a larger scale. The transmissive design of our device differs from reflective designs [2,42] which require the input source waves to be on the same side as the output for operation. This transmissive characteristic could simplify integration with commercial devices, where it could potentially be part of a thin partition or window.…”

“…Tunable acoustic wave manipulation is a well-researched problem that has seen recent developments using various acoustic devices, such as phononic crystals, [1] reconfigurable acoustic metamaterials, [2][3][4] or dynamic acoustic phased arrays [5,6] to achieve applications like frequency-selective wave beaming, [7] acoustic wave steering, [8] and numerous other holographic applications. [6] In the last decade, continuous research efforts have been made to design and develop active designs, [9,10] which may utilize control mechanisms like mechanical, heat, or electric control, for attaining structural variation to allow dynamic sound modulation.…”

“…While phased arrays are powerful acoustic devices for dynamic sound modulation, they come with the challenges of the need for precise calibration, the high cost of hardware, aliasing effects, and electronic control complexity. [2,13] Alternatively, other acoustic devices such as metamaterials have emerged to enable a myriad of applications such as lensing, energy harvesting, near-perfect absorption, and beam focusing. [14][15][16][17] Different designs of acoustic devices have been developed [18,19] such as labyrinth structures, [20,21] Helmholtz resonators, [22][23][24][25] and multiapertures, [26,27] and some are even compatible with phased arrays.…”