Physics: A sound design for 3D displays

A system that can generate a 3D image that can also emit sound and provide a tactile response when ‘touched’ is reported in Nature. The prototype, which resembles displays seen in science-fiction movies such as Star Wars, may have applications in biomedical and computational-fabrication fields.

Ryuji Hirayama and colleagues created the Multimodal Acoustic Trap Display, which can simultaneously produce visual, auditory and tactile content. Based on the principles of acoustic tweezers (where the position and movement of very small objects can be manipulated using sound waves), the system uses sound waves to trap a particle and illuminate it with red, green and blue light to control its colour as it moves through the display. The authors demonstrate their system by producing 3D images, including a torus knot, a pyramid and a globe, which can be seen from any point around the display. By using acoustic fields to create the images, this also means that they can also produce sound coming from the displayed content, as well as tactile feedback. For example, they produce an audio-visual countdown timer that users can start and stop by tapping their finger on the display.

The prototype demonstrated in the work brings us closer to displays that could provide a fully sensorial reproduction of virtual content, the authors conclude.