LCD display on the skin
Thin seven-segment display based on polymer LEDs
it functions on the surface of the back of the palm.
Researchers at the University of Tokyo, working under the guidance of Professor Takao Someya, have developed an ultra-thin and ultra-flexible protective coating and created a display based on air-stable organic LEDs with its help. This technology will allow the development of skin displays for visualizing blood oxygen levels, heart rate for athletes and many other purposes.
Many scientists around the world are working on methods of integrating electronic devices into the human body for biomedical purposes. To minimize the impact on the place of attachment to the body, the electronics intended for permanent wear should be thin and flexible. However, most of the devices developed to date are enclosed in glass or plastic substrates with limited flexibility, the thickness of which reaches several millimeters. And thin and flexible organic devices, the thickness of which is measured by micrometers, have so far decomposed rapidly under the influence of air.
In search of a solution to this problem, the authors have developed a high-quality protective film with a thickness of less than 2 microns, suitable for the manufacture of ultra-thin and ultra-flexible high-quality electronic displays and other devices designed for permanent wear. The protective film consists of alternating layers of inorganic (silicon oxynitrite) and organic (parylene) materials. It prevents the penetration of air and water vapor into the device, increasing its service life from several hours (for earlier prototypes) to several days. In addition, the developers managed, without damaging the film, to attach transparent indium-tin-oxide electrodes to its surface, which demonstrates the possibility of using the development for the production of skin displays.
Using their protective film and indium-tin-oxide electrodes, the authors created polymer LEDs and organic photodetectors. Their exceptionally small thickness provides the possibility of attachment to the skin, and flexibility – the possibility of stretching and deformation during the movement of the body. The thickness of the new polymer light-emitting diodes is only three micrometers, and the efficiency is more than six times higher than the efficiency of earlier analogues. This reduces heat generation and energy consumption, providing the possibility of direct attachment to the skin surface for medical purposes, such as visualization of various biological parameters. The authors also combined red and green polymer LEDs with photodetectors, which allowed them to demonstrate the operation of the oxygen level sensor in the blood.
According to Professor Someya, despite the fact that after the revolution in the field of communications after the advent of mobile phones, such devices are becoming smaller and smaller, they are still separate devices that we have to carry with us. It is quite possible that in the future they will be replaced by skin displays, which will not only save us from unnecessary devices, but also give new colors to communication.
Article by Tomoyuki Yokota et al. Ultraflexible organic photonic skin is published in the journal Science Advances.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on EurekAlert!: Ultrathin organic material enhancements e-skin display.
19.04.2016