‘Tweezers Of Sound’ Can Pick Up Objects Without Any Physical Contact

by : Emily Brown on : 25 Jul 2021 12:57
'Tweezers Of Sound' Can Pick Up Objects Without Any Physical ContactShota Kondo and Kan Okubo 2021 Jpn. J. Appl. Phys. 60 SDDD16

A new technology developed by scientists from Tokyo Metropolitan University allows for objects to be picked up without any physical contact. 

Dubbed ‘tweezers of sound’, the technology utilises acoustic trapping, which involves sound waves being used to manipulate small objects.


Footage of the technology shows a small polystyrene ball hovering in the air thanks to ultrasound transducers, which generate a 3D acoustic field. In turn, the field is able to stably trap and lift the ball into the air, as if it was being picked up by a set of invisible tweezers.

Tweezers of sound (Shota Kondo and Kan Okubo 2021 Jpn. J. Appl. Phys. 60 SDDD16)Shota Kondo and Kan Okubo 2021 Jpn. J. Appl. Phys. 60 SDDD16

The technology comes from researcher Shota Kondo and associate professor Kan Okubo of the Tokyo Metropolitan University, who manipulated millimetre-sized objects using a hemispherical array of transducers with phase and amplitude control.

Scientists have long used another method, known as optical trapping, to move objects without touching them by using laser light. However the method has limits on the properties of the objects which can be moved. Acoustic trapping, on the other hand, can be applied to a wider range of object sizes and materials.


See footage of the acoustic trapping below:


The method involves splitting the array of transducers into blocks, and using an inverse filter that finds the best phase and amplitude to drive the blocks to make a single trap, Eurekalert reports. By adjusting how they drive the blocks over time, the researchers can change the position of the target field and move the object they have trapped.

The researchers have demonstrated their findings with simulations of the 3D acoustic fields that are created by the arrays, as well as with their experiments with the polystyrene ball.


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Emily Brown

Emily Brown first began delivering important news stories aged just 13, when she launched her career with a paper round. She graduated with a BA Hons in English Language in the Media from Lancaster University, and went on to become a freelance writer and blogger. Emily contributed to The Sunday Times Travel Magazine and Student Problems before becoming a journalist at UNILAD, where she works on breaking news as well as longer form features.

Topics: Science, no-article-matching, Research


  1. EurekAlert

    Tweezers of sound can pick objects up without physical contact