As more people use wearable devices like smart watches these days, we encounter them in our daily lives more often. The wearable device market is growing every day, and products are diversifying too from wrist bands to glasses, and ones attachable to clothing.
The most popular types are still smart watches and wrist bands that are designed to provide diverse functions when connected to smart phones. Watch Urbane from LG Electronics was also designed to operate in connection with a smart phone, even though it has its own communication function.
Smart watches can make our lives much more convenient by letting us have all those useful functions right on top of our wrists. Wearing a watch is much easier than carrying a smart phone, but the fact that we still have to carry something doesn’t change.
Recently, devices are being developed that can be attached to clothing or even skin. Let’s take a look at the evolving field of wearable products that we don’t have to worry about carrying as much.
What made the current success of the wearable device market possible was the smart watch. Other devices like smart glasses and head-mounted displays for virtual reality technology are also being developed, but they’re not as marketable as smart watches. The reasons the smart watch’s development became such a major part of the market are various, but the following three are considered especially important.
① Component Size
The first reason is the fact that it’s hard to make devices very tiny, due to the sizes of its required components. It is true that many devices became smaller and lighter, thanks to smaller sensors, batteries with increased capacity, and flexible displays that have become available recently.
Their sizes, however, are still considered a bit too large to be used in accessories like glasses and rings. This is one reason smart watches, which aren’t under much pressure for lighter and smaller designs, have the most reasonable shape for a wearable device.
The second reason is related to UI implementation. Many smartphone users find smart watches easier to use because of their intuitive displays, touch screens and their easy access.
③ Diverse Functions
The last reason is that they can have diverse functions developed for wearable devices. This factor is also related to the size of the device mentioned earlier.
Smart watches can contain more components compared to other wearable devices, and converge various sensors to provide diverse functions. Multiple sensors like data networks, GPS, and Gyro sensors help smart watches provide a number of functions, and improve user convenience.
If components become even smaller and control technology improves, then more diverse forms of wearable devices such as rings, earrings, glasses, and clothing may be developed.
Now let’s see what kind of wearable technologies that we won’t have to physically carry are being developed by university research teams.
① Stress-Level Measuring Patch Attachable on Skin
In April of this year a research team led by Prof. Yeong-Ho Cho at KAIST Bio/Brain Engineering Department developed a patch which analyzes skin temperature, sweat secretion, and pulse waves.
In the past, only one type of data (either pulse waves or skin temperature) was used for stress measurement and analysis, so it was difficult to tell whether symptoms were the result of stress or other physical problems.
The patch developed by Prof. Cho’s team was designed with thinly stacked layers with sensors for skin temperature, skin conductivity, and pulse wave. These sensors analyze multiple types of data to measure the level of stress more accurately. The patch is as small as a postage stamp and the material is flexible as well, so their technology is expected to be applied to various wearable devices.
The patch is also designed to provide power by adding a piezoelectric device which creates electricity through the changing pressure caused by the pulse. This means the patch will require either no extra power source, or only a small amount if needed.
② Solar Battery Embedded under Skin
A research team led by Prof. Jong-Ho Lee at GIST recently developed a thin, flexible solar battery. Unlike existing solar batteries with limited flexibility that were easy to break, this battery succeeded in separating the thin solar layer and adding it to film, so that it won’t break or separate from skin when embedded into the human body.
This battery was first developed to provide a small amount of power to pacemakers.
Existing pacemakers had to have their batteries changed every five to seven years, and patients had to go through surgery for this procedure. With flexible solar batteries, patients can be supplied with solar power directly through their skin, and no longer need to change batteries.
What’s especially impressive about these solar batteries are their diversity in size and flexibility. The batteries are separated into six to seven micrometer layers and then put on film to become foldable solar batteries. Thanks to their flexibility, they can be embedded even in areas where diverse movement is required.
As these batteries can generate quite a large amount of power, they’re expected to supply power to other types of electronic equipment that are designed to be embedded into the human body to measure various information.
③ Extra Fine Electronic Circuit Transplantable onto Skin
A research team led by Prof. Jack Ma at Wisconsin-Madison University developed a micro-electronic circuit that can be transplanted onto skin. This integrated circuit can be engraved directly onto skin, using a method similar to that of tattoos.
The engraved circuit can replace wearable devices and is expected to be utilized in diverse fields since it supports 5G communication frequency. One use is for monitoring patient status in real time and linking to the hospital’s system for immediate response during emergency situations.
With the micro-electronic circuit, users don’t have to worry about carrying wearable devices.
④ Electronic Fiber Attachable to Clothing
The electronic fiber, which was developed by a research team led by Prof. Heung-Jo Ko at GIST, is a type of fiber that can be attached to cloth. This fiber was designed with a cilia-like structure so it can stick to objects with rough surfaces. For example, it can be put on top of stones or plants with rough surfaces, and won’t come off, thanks to its artificial cilium.
This fiber is not ruined even when washed in water, so the clothing with this fiber attached can be washed without worrying about malfunctions.
Electronic fibers can be developed in multiple fields, but those attachable to clothing are expected to boost the wearable market the most. The fiber can also have complicated circuits drawn into them relatively easily, so technologies which fuse multiple sensors with it or which utilize it as a circuit will be developed in the near future.
These technologies are still quite limited in their functions and applicable fields. As they continue to advance, however, wearable devices that can be carried in the form of accessories or attached to clothing and skin will be developed to make our daily lives more convenient and smarter.
I look forward to seeing the future with diverse wearable devices.
Written by Woonje Sung, LG CNS Student Reporter
 Pulse wave: A pulse wave or pulse train is a kind of non-sinusoidal waveform that is similar to a square wave, but does not have the symmetrical shape associated with a perfect square wave. It is a term common to synthesizer programming, and is a typical waveform available on many synthesizers. The exact shape of the wave is determined by the duty cycle of the oscillator. (Source: https://en.wikipedia.org/wiki/Pulse_wave) [back to the article]
 Pacemaker: A pacemaker (or artificial pacemaker, so as not to be confused with the heart’s natural pacemaker) is a medical device which uses electrical impulses, delivered by electrodes contracting the heart muscles, to regulate the beating of the heart. (Source: https://en.wikipedia.org/wiki/Artificial_cardiac_pacemaker) [back to the article]
 Integrated circuit: An integrated circuit or monolithic integrated circuit (also referred to as an IC, a chip, or a microchip) is a set of electronic circuits on one small flat piece (or “chip”) of semiconductor material, normally silicon. This can be made much smaller than a discrete circuit made from independent electronic components – a modern chip may have several billion transistors in an area the size of a human fingernail. (Source: https://en.wikipedia.org/wiki/Integrated_circuit) [back to the article]