17-06-2021 | | By Robin Mitchell
Recently, Samsung announced the development of a flexible OLED display that could provide invaluable to future wearable devices. What challenges do wearable devices face, what has Samsung developed, and what applications could it help with?
Of all industries that electronics have been integrated into, wearable devices have arguably been the most challenging. Unlike most electronic applications, wearable devices are required to be comfortable to wear while having enough functionality to be practical and commercial.
The clothing industry is one of the oldest in human history dating back to the first uses of animal skins to keep man warm. Despite how far technology has come, there are still some fundamentals behind clothing and biology that make integrating electronics extremely difficult.
The first challenge faced by wearable devices is that they need to conform to the wearer. This is easily done for worn fabrics which can stretch and compress to fit around different body shapes, but electronics are fundamentally inflexible. This means that electronic circuits are almost always ridged by design, and thus cannot conform to skin.
The second challenge faced by wearable devices is their need to be comfortable. Ridged objects are generally not comfortable to wear, and large ridged devices such as watches are arguably falling out of fashion in favour of smartphones. The comfortability of a device is further impeded when trying to improve the functionality of that device. Large displays and big processes are great for creating a powerful device, but if that device is too rigid and uncomfortable, then the resulting device will be unpopular.
The third challenge faced by wearable devices is the need for the device to survive reliably under many thousands of mechanical cycles (i.e. movement, stretching, and washing). A device that can conform to the human body while remaining functional is only practical if it can be used many hundreds of times with little to no damage. If a device fails after two or three uses then not only does that make it undesirable as a product, it also presents an environmental challenge.
Recognising the need for flexible electronics Samsung have recently announced the development of a fully flexible OLED display that can be stuck to the skin and conform to its surface. To create a flexible display, Samsung created individual OLED pixels which themselves are ridged, but sit on a flexible elastomer surface. Connections between the OLEDs are made using a flexible material as are the traces that connect the display to the driver system.
The creation of “ridged islands” that connect on a flexible sea enables the display to flex and stretch with little to no damage. In fact, the research team at Samsung demonstrated the capabilities of the display by stretching it over 1,000 times with the display still operating. Samsung took the new design further and integrated basic medical sensors. The result was a medical monitoring device that can pick up signals 2.4 times stronger than typical devices thanks to its ability to get right up to the skin (similar to a plaster).
It should be noted that the display created by Samsung is far from a commercial device due to its low resolution, but the ease of creation demonstrates that it is a real candidate for a future commercial device. Such displays will most likely be used in medical monitoring applications where sensors can obtain good adhesion to the skin surface which allows for more accurate medical data.
Such displays could also be useful in wearable smart devices such as smartphones that can conform to a forearm. If coupled with touch screen technology, interactive wearable devices could be made that are comfortable to wear while providing practical applications such as calls, texts, and internet browsing.
Wearable technologies have a long way to go, and most devices designed by researchers are generally just for inspiration and proof-of-concept. However, as wearable screen resolutions improve and wearable processors become more powerful, it will only be a matter of time before wearable electronics truly take off.