Ultrasound Haptics


Ultrasound haptic technology creates mid-air haptic sensations using focused ultrasound waves, so that people can experience haptic feedback against the hands without any physical contact with a device. There are numerous benefits of this technology, especially for touchless user interface design. To keep this introduction short, I recommend reading our recent survey paper of this technology [1] if you want more details about the technology and its applications.

I have been involved in the ultrasound haptics community for a long time (since 2012) and have sporadically done research in this area. On this page, I give a brief overview of some of my research into ultrasound haptics.

ultrasound array
An ultrasound haptics device consists of an array of ultrasound emitters. These are typically, although not always, in a rectangular layout.


One of my research interests is the perception of ultrasound haptic sensations. Since this is an emerging haptic technology, we still only have a basic understanding of how its tactile sensations are perceived by the body. In addition to this, it is so radically different from existing haptic technologies (e.g., vibrotactile) that little existing knowledge can be transferred. Research is needed to better understand the relationships between rendering characteristics and perception, so that we can make the most of the technology.

Research highlights:


One promising application for ultrasound haptic technology is in giving feedback for touchless mid-air gesture interaction. Touchless gestures have great potential but their adoption has been hampered by numerous usability issues [4]. Ultrasound haptic feedback can potentially help to alleviate these issues. A key benefit of this technology is that interaction feedback can be spatially coupled with the user’s input actions: in other words, haptic feedback can be given directly to the user’s hands whilst they gesture.

My work has explored various ways of integrating ultrasound haptic feedback in touchless user interface design, including using ultrasound haptic feedback to help users find a good hand position for touchless interaction [5] and giving confirmatory feedback about input gestures [6].

Photo of the HaptiGlow system. An Ultrahaptics UHEV1 device with a strip of LEDs around the front edge and left and right sides. The LEDs are green, indicating that the user has their hand in a good position.
One application of ultrasound haptics is helping guide hand movements in mid-air, e.g., like we did in the HaptiGlow project.

Research highlights:


Research highlights:


[1] A Survey of Mid-Air Ultrasound Haptics and Its Applications
I. Rakkolainen, E. Freeman, A. Sand, R. Raisamo, and S. Brewster.
IEEE Transactions on Haptics, vol. 14, pp. 2-19, 2020.

[2] Perception of Ultrasound Haptic Focal Point Motion
E. Freeman and G. Wilson.
In Proceedings of 23rd ACM International Conference on Multimodal Interaction – ICMI ’21, accepted to appear. 2021.

[3] Enhancing Ultrasound Haptics with Parametric Audio Effects
E. Freeman.
In Proceedings of 23rd ACM International Conference on Multimodal Interaction – ICMI ’21, accepted to appear. 2021.

[4] Do That, There: An Interaction Technique for Addressing In-Air Gesture Systems
E. Freeman, S. Brewster, and V. Lantz.
In Proceedings of the 34th Annual ACM Conference on Human Factors in Computing Systems – CHI ’16, 2319-2331. 2016.

[5] HaptiGlow: Helping Users Position their Hands for Better Mid-Air Gestures and Ultrasound Haptic Feedback
E. Freeman, D. Vo, and S. Brewster.
In Proceedings of IEEE World Haptics Conference 2019, the 8th Joint Eurohaptics Conference and the IEEE Haptics Symposium, TP2A.09. 2019.

[6] Tactile Feedback for Above-Device Gesture Interfaces: Adding Touch to Touchless Interactions
E. Freeman, S. Brewster, and V. Lantz.
In Proceedings of the International Conference on Multimodal Interaction – ICMI ’14, 419-426. 2014.

[7] Textured Surfaces for Ultrasound Haptic Displays
E. Freeman, R. Anderson, J. Williamson, G. Wilson, and S. Brewster.
In Proceedings of 19th ACM International Conference on Multimodal Interaction – ICMI ’17 Demos, 491-492. 2017.

[8] UltraPower: Powering Tangible & Wearable Devices with Focused Ultrasound
R. Morales Gonzalez, A. Marzo, E. Freeman, W. Frier, and O. Georgiou.
In Proceedings of the Fifteenth International Conference on Tangible, Embedded, and Embodied Interaction – TEI ’21, Article 1. 2021.