Grand Challenges in Wearable Electronics

Wearable technology has deep roots in history, with eyeglasses and wrist and pocket watches being two of the most prolific technologies still being in use today. These technologies developed and evolved over the centuries. For example, watches started as decorative pieces based on an oscillating wheel and gear mechanism, later acquiring a primitive form of energy harvesting (selfwinding), progressing to electromechanical and then to fully electronic devices (McCrossen, 2013). Future watches may integrate sophisticated electronics, solar or thermal energy harvesting, carry a huge variety of functions beyond timekeeping and still be a decoration and a fashion statement. Eyeglasses is another vivid example, starting as assistive technology (Letocha and Dreyfus, 2002), also evolving to become a fashion accessory, frequently used by individuals who do not need vision correction. Eyeglasses are rapidly becoming a high-tech electronic device, with Google Glass, Alexa Frames, and the likes paving the way to everyday use of augmented reality. The long-term success of these two technologies is based on their utility, deep integration with daily activities, and social acceptance by the population (Degerli and Ozkan Yildirim, 2020). These examples are very valuable when we consider the challenges facing wearable electronics today. Future growth in wearable devices is tightly coupled with advances in semiconductor technology and electronics. Wearables integrate a power source, sensors, data processing and storage core, actuators and displays, and a communication interface, packaged in a small, lightweight device that is worn on the body or integrated with everyday wear items, such as clothing, footwear, or accessories. Such wearables exemplify the cutting edge of the electronics, demanding the highest performance for the least amount of power, in the least amount of space, and in a challenging operating environment. Here wearables may gain a valuable lesson from a recent success story– the emergence of the smartphone as a ubiquitous communication device. The demands of modern smartphones closely match those of wearable devices, albeit in a larger package. The driving force behind the innovation andminiaturization of smartphones is high acceptability and demand across different cultures, generations, and societies. Resonating with the success of watches and eyeglasses, smartphones have a great utility that is tightly integrated into our life. Wearables may just as well become the next success story if they find an application that is demanded by the masses and if the electronic technology can support the effortless integration of wearables into the daily routine. Looking into the electronic technologies that form the foundation of wearable devices, we can highlight several distinct areas: