Self-bending of a beam of sound was previously achieved by an acoustic metasurface that modified the amplitude and phase modulations. However, fabricating a fine-structured device for ultrasound is difficult because it has a short wavelength. In this paper, we propose a simple binary acoustic lens for a self-bending ultrasound beam in air at 40 kHz. The lens has transparent and opaque areas and was designed using the Airy function. The beam bending was evaluated by simulations and experiments. The simulations showed that the proposed lens achieved beam self-bending, although the concentration of energy in the main beam was inferior to that for phase-coded modulation. The experiments demonstrated that self-bending is feasible using a binary lens made of a polypropylene sheet, and the measured sound fields agreed well with the simulations. These results suggest that a self-bending beam of ultrasound is possible with a lens having a simple binary structure.

声束的自弯曲以前是通过修改振幅和相位调制的声学超表面实现的。然而，制造用于超声波的精细结构装置很困难，因为它的波长很短。在本文中，我们提出了一种简单的二元声学透镜，用于 40 kHz 空气中的自弯曲超声波束。镜片具有透明和不透明区域，并使用 Airy 功能设计。通过模拟和实验评估梁弯曲。模拟表明，尽管主光束中的能量集中不如相位编码调制，但所提出的透镜实现了光束自弯曲。实验表明，使用由聚丙烯片制成的二元透镜进行自弯曲是可行的，并且测量的声场与模拟非常吻合。