Healthcare at your fingertips: miniaturization challenges of sensors & actuators in the wearables market

Many consumers have now embraced wearables, which come in various shapes and forms, including smartwatches, smart bracelets, smart rings, TWS (True Wireless Stereo) earbuds, smart patches, and AR/VR headsets. According to Yole Intelligence’s Sensors & Actuators for Wearables 2023 report, in 2022, the total number of wearable end systems was estimated at 0.95 billion units, and we forecast it will reach 1.20 billion units in 2028 with a 4% CAGR_22-28 (volume). In terms of sensors and actuators, this represents a global market of almost 4.17 billion units (US$3.58 billion) in 2022, and the market is expected to grow to 6.77 billion units (US$5.7 billion), with a ~8% CAGR_22-28 (volume and revenue growth).

Originally designed for monitoring fitness activities, smart wearables now offer the capability to track a wide range of metrics, including cardiac and respiratory markers, temperature, sports activities, sleep quality, and stress levels. These devices are even used for accident and fall detection. Among the different end systems, smart rings are attracting growing interest from big tech companies. Indeed, in the present economic downturn, smart rings present a more budget-friendly option compared to smartwatches, making them an appealing alternative that stands to benefit from the current situation. Nevertheless, there are still several questions that arise concerning functionalities, performance, use cases, and rate of adoption by consumers.

Smart rings account for a relatively small portion of the global wearables market. In 2022, their sales reached 0.6 million units, but the projection for 2028 anticipates a significant increase to 1.6 million units. At the sensor and actuators level, this translates to growth from US$0.4 million in 2022 to US$1.3 million by 2028. Indeed, major tech companies have yet to address this market, although their extensive patent filings indicate a keen interest and the potential for exciting technological advancements.

Currently, the smart ring market is an oligopoly and profitable, providing opportunities for startups like Oura Rings, Circular xyz, Movano Health, Noise, and McLear to thrive. As an example, Oura, established in 2013, achieved a significant milestone in 2022 by selling over 1 million Oura rings. This success can be attributed to the visibility gained through partnerships with renowned organizations, such as the NBA, Real Madrid, NASCAR, Aston Martin Red Bull Racing, and World Surf League. However, this situation is unlikely to last indefinitely. As the sector continues to show promise and growth, it is only a matter of time before big tech players enter the scene, potentially reshaping the landscape and posing both challenges and opportunities for the existing players.

Indeed, several rumors surrounding the development of smart rings by big players such as Samsung, Microsoft, Google, and Apple are frequently discussed in the industry. The latest is Samsung’s smart ring, called the “Galaxy Ring,” which has reached the prototype phase and appears poised for integration into various health and wellness monitoring software applications. An announcement is expected in end-2023 or early 2024.

Like smartwatches, smart rings serve as fashionable accessories and go beyond being mere gadgets for customers. With their attractive and customizable designs, these shiny smart objects evoke an emotional attachment in users akin to what jewelry can provide. These connected devices could be categorized into three types:

First, smart ring types that enable contactless data transfer using NFC chips. This type of smart ring has, in most cases, only one function. It is often used for payment transfers and has a final price between US$5 to US$50.

Second, smart rings are dedicated to communication (phone calls, assistant control such as Alexa, Google) by vibrating, for example, or by integrating audio sensors and actuators directly into the ring. They are sold at a price of around US$150.

And at last, Smart tracker rings have several functions and embed different types of sensors and actuators, such as temperature sensors, inertial sensors, RF antennas, microphones, micro speakers, or photoplethysmography (PPG) modules. These smart rings monitor the user’s movements, heart rate, and SpO₂ and provide information for sports, sleep quality, or health monitoring. They are sold at a price between US$50 and US$400.

Upon examining the distinct features of smart rings, it becomes evident that they do not incorporate entirely novel sensors or functionalities compared to other wearables already on the market. For instance, in its OURA Ring Gen3 analysis, Yole SystemPlus, also part of Yole Group, revealed that it integrates an IMU (Inertial Measurement Unit) comprising an accelerometer and gyroscope from Bosch, a digital temperature sensor from Maxim Integrated and a PPG (Photoplethysmogram) module.

This raises several questions about their appeal to consumers. In comparison to smartwatches, smart rings offer no additional benefits, and incorporating sensors into earbuds to monitor cardiac markers, for example, seems to make more sense. This is because biological signals are more accurately captured at the ear level. Adding that to the manufacturing aspect, this market presents several challenges that need to be overcome. Indeed, most of the smart rings already commercialized are not waterproof, primarily due to the complexities associated with the assembly of the diverse spare parts and the material used (i.e., optically transparent for the integration of the PPG sensor). Because of their circular shape and small footprint, the sensors and battery must be carefully integrated into them. Additionally, the power consumption has to be well managed through the choice of the sensors to be integrated, as must the data collection and transfer. Typically, smart tracker rings show a battery autonomy of one week. Other factors that demand vigilance are material compatibility and longevity, users’ finger sizes, comfort, and price.

Smart rings differ significantly from smartwatches, as they lack features like integrated displays and rely on a connection to a smartphone or smartwatch for data visualization. This distinction may contribute to them being potentially less addictive than smartwatches. For instance, Amazon, a major tech company, released a smart ring called “Echo Loop” for Alexa control in 2019. However, within a year, Amazon discontinued its production without attempting further improvements.

Nevertheless, we can expect several improvements and new use cases for such devices. There was much speculation surrounding Apple’s VR headset, the Vision Pro, suggesting that it might be paired with smart rings to enable precise tracking of finger motion. However, in the end, Apple chose not to proceed with this approach. Reflecting on the history of smartphones, Apple’s first iPhone was controllable with fingertips, while Samsung launched the Galaxy Note with an S pen that offered precise control. Drawing an analogy from the smartphone industry, it is possible that Samsung could soon release its own version of a VR headset that could be controlled with a smart ring. These advancements and innovative applications may shape the future of smart rings, expanding their functionalities and enhancing user experiences for specific applications.

After the success of fitness bands, smartwatches, and TWS earbuds, the wearables industry is quite dynamic compared to other mature consumer markets, such as smartphones. Players involved in the development of sensors and actuators for such end systems are working on miniaturization, energy consumption optimization, and the performance of sensors. Recently, USound announced several collaborations with players (LINNER, Luxshare-ICT) in the field of audio technology to integrate their MEMS micro-speaker technologies into TWS earbuds and hearing aids. SilMach manufactures micromotors named PowerMEMS® that could be integrated into connected devices such as mechanical smartwatches. The solution enables them to animate independently and in “direct drive”, the hands of a movement in both directions of rotation in a reduced volume. Additionally, the decorrelation of the hands makes it possible to indicate the time or control auxiliary functions (biometrics, sports activities).

All the innovation in the domain should lead to a new generation of end systems benefiting from sensors and actuators with reduced form factors and integrating more functionalities.

Source: yolegroup.com

Clyde Midelet, Ph.D., is a Technology & Market Analyst, Sensing and Actuating in the Photonics & Sensing division at Yole Intelligence, part of Yole Group. Clyde is engaged in developing technology and market reports covering microfluidics technologies and related markets. He daily investigates various topics such as point-of-care diagnostics, life sciences research, and manufacturing processes. In addition, Clyde collaborates with Yole’s MEMS analysts to perform specific analyses combining microfluidics and MEMS. After a master’s in solid state chemistry from Rennes University (France), Clyde did a Ph.D. at the Ecole Normale Supérieure de Rennes (France) in collaboration with the laboratory SATIE (France). His research in the field of microfluidics led to various scientific papers, and he developed a system for electrical micromanipulation of gold nanoparticles for biosensing in vitro diagnostics. Furthermore, he worked on an industrial project in next-generation displays using quantum dot technology.

Pierre Delbos is a Technology & Market Analyst, Sensing and Actuating, in the Photonics & Sensing division at Yole Intelligence, part of the Yole Group. He is involved in developing technology and market reports covering MEMS & sensing technologies, including magnetic sensors, optical and audio MEMS, as well as gas and particle sensors. Pierre also collaborates with his team on custom studies for the key players in the MEMS industry. Pierre holds a master’s in Microelectronics and Photonics Engineering from the Grenoble Institute of Technology, PHELMA (France).