World-First: Alps Alpine and Utsunomiya University Jointly Develop “Stealth Aerial Interface” Mid-Air Display and Input Device

Next-Generation HMI for Extra Safety, Comfort and Emotion in Touchless Control

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January 18, 2022

In the world-first, Alps Alpine Co., Ltd. (Tokyo: 6770; President & CEO: Toshihiro Kuriyama) and Utsunomiya University have jointly developed the “Stealth Aerial Interface,” a next-generation human-machine interface (HMI) product realizing both aerial display – using aerial imaging by retro-reflection – and mid-air input and control – based on high-sensitivity capacitive sensing – while also incorporating stealth icons for superior design as an application of decorative printing technology. The Stealth Aerial Interface will deliver a brand-new touchless control experience providing safety, comfort and emotion for users in the New Normal. Alps Alpine and Utsunomiya University unveiled the product together at International Display Workshops (IDW ’21), an academic display technology conference held December 1-3, 2021, and received positive responses from experts in the display industry. After conducting market research and bringing the product to a heightened level of completion, we aim initially for adoption of the product by 2025 in display and control applications in public places, like elevators and ticket machines, and areas requiring security considerations.

Background to the Development

There are many situations where people would prefer to avoid directly touching input devices in public places. Elevator buttons, train ticket machines, supermarket self-checkout systems… Who else might have touched them? What if they are not clean? What if their own hands are dirty? This aversion to touching has become even more pronounced of late due to the global COVID-19 pandemic and increasing fear of disease transmission. Other social concerns include the theft of fingerprints left behind on controls during touch operation. Such hygiene considerations and security risks highlight the growing need for non-contact operation of input devices in a society transitioning to the New Normal.

With existing non-contact control devices, however, users feel stressed not being able to intuitively sense the distance from which they can operate them and they ultimately resort to touch. Touchless controls will only become mainstream when they allow comfortable, intuitive operation.

Alps Alpine has been developing mid-air input devices through application of original high-sensitivity capacitive sensing technology since 2008 and picked up the pace of product development following the recent spike in demand for touchless control, even acquiring the AirInput™ trademark. In May 2021, AirInput™ solutions were adopted on trial for use in elevator and indoor lighting applications1. Since then, Alps Alpine has been conducting ongoing sales promotion activities in connection to the AirInput™ line in preparation for mass production in 2022. Within the field of optics, a core technology domain established through activities including development of optical communication lenses, Alps Alpine has also been developing elemental technology relating to aerial imaging by retro-reflection since 2019.

Yamamoto Laboratory at Utsunomiya University has been conducting research relating to 3D displays and multimodal kansei (affective) information science – in particular, aerial imaging by retro-reflection (AIRR) – since 2014. Prof. Hirotsugu Yamamoto, the principal investigator of the laboratory, is a pioneer in the field of aerial interfaces and has received numerous awards on his research and development.

With a view to realizing comfortable, more intuitive non-contact operation and accelerating the spread of touchless devices in society, the two parties have moved to commence joint development involving the fusion of touchless control devices developed by Alps Alpine using original high-sensitivity capacitive sensing with retroreflection technology based on aerial imaging theories researched by Utsunomiya University.

Outline of the Development

The jointly developed Stealth Aerial Interface combines a mid-air input device – based on high-sensitivity capacitive sensing – with aerial imaging functionality – an application of retroreflection technology – to enable comfortable, intuitive and stress-free touchless device operation by interacting with the image in mid-air, as if operating any switch, touch panel or other conventional touch-controlled device.

The Stealth Aerial Interface also makes use of decorative printing technology to enhance the design of the final product. At first glance, the surface is not distinguishable as a display, masterfully crafted to look like wood, metal or another material. Only when a hand approaches, affecting the capacitance, do stealth icons appear in mid-air.

Touchless operation lowers the risk of disease transmission and the risk of fingerprint theft, contributing to user safety, while excellent operability and a design that blends in with the space to avoid any diminishing of the surrounding atmosphere provide unprecedented comfort and emotion to deliver a novel touchless control experience.

This jointly developed product is the world’s first human-machine interface (HMI) integrating capacitive sensing, aerial display, and decorative printing technologies. Advantages over use of cameras and infrared light for the non-contact technology are high input accuracy, especially during operations in close proximity, and excellent design performance. Furthermore, because there is no need to install sensors or projectors outside the package, there is greater flexibility in end product design, creating potential for use in a broad range of applications.

Alps Alpine possesses unique strength in the ability to handle everything from the supply of the components – high-sensitivity capacitive sensors and optical elements for aerial imaging – to the design of the user interface (UI) – for ensuring clear communication of information to users – and system design for connecting them together and enabling smooth, suitable output corresponding to the input. The product will be brought to a heightened level of completion through application of research relating to aerial display control, an area where Utsunomiya University has been a global pioneer.

Alps Alpine and Utsunomiya University unveiled the product together at the world’s biggest academic display technology conference, International Display Workshops (IDW ’21), held December 1-3, 2021, and received positive responses from experts in the display industry.

<Roles in the Joint Development>
Utsunomiya University
 • Develop theory relating to control of aerial images
 • Capture trust in the technology through conference presentations

<RoleAlps Alpine
 • Develop hardware design and control technology ideal for aerial interfaces
 • Develop an optimal UI and system control technology to match users and usage environments
 • Commercialize and sell the product


After conducting market research to further identify needs and issues and bring the product to a heightened level of completion, we aim initially for adoption of the product in displays and controls in public places, like elevators and ticket machines, by 2025. We will also explore applications in amusement equipment and automotive systems. Beyond that, we have our sights on a world where extended reality (XR)2 services are commonplace and plan to advance development with a view to deploying the product as a visual information presentation device with little impact on the body given that goggles and other wearable devices are not required. Our aim is to provide safety, comfort and emotion to users of human-machine interfaces (HMI) in the New Normal and contribute to a world after 2030 where people and cyberspace seamlessly interact.

1.Press release, May 27, 2021: “AirInput™ Solutions Trialed for Mid-Air Control of Elevators and Lighting in New Building of Recruit Co., Ltd.”
2.Extended reality (XR) is a collective term referring to a range of virtual environment technologies, such as virtual reality (VR) and augmented reality (AR). XR technology integrates real and virtual worlds to provide new experiences and allow new types of simulations that cannot be achieved in the real world.

About Alps Alpine Co., Ltd.

Alps Alpine, a leading manufacturer of electronic components and automotive infotainment systems, has brought the world numerous “First 1 ” and “Number 1” products since its founding in 1948. With strengths in developing products that integrate and build on core technology and expertise in the areas of human-machine interfaces, sensing, connectivity, software development and system design, Alps Alpine supplies roughly 40,000 different products and solutions across diverse domains. Those offerings include devices such as switches, sensors, communication modules, touch panels, camera actuators and power inductors; electronic shifters, remote keyless entry systems and other automotive units; system products such as digital keys based on smartphone app and blockchain technology, and remote monitoring; and aftermarket electronics like car navigation and audio systems. Operating 110 bases in 26 countries and regions, the Alps Alpine Group serves around 2,000 companies worldwide primarily within the automotive, energy and industry markets, and the consumer electronics market, including mobile devices.
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About Utsunomiya University Yamamoto Laboratory

The principal investigator (PI) is Hirotsugu Yamamoto (professor, Department of Fundamental Engineering Information, Electronics, and Optics Course, School of Engineering; head of real-world information optics at the Center for Optical Research and Education (CORE); deputy director, Robotics, Engineering and Agriculture-technology Laboratory (REAL)). Prof. Yamamoto engages in education and research in the area of optical engineering in corporation with Shiro Suyama (Project Professor, CORE) and Masaki Yasugi (Project Associate Professor, CORE). The laboratory covers aerial display basics through to social implementation, including development of international standards, VR biology experiments employing underwater displays, and application of these fields to artificial intelligence.
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