Ultra thin film-like organic
transistor integrated circuits are being developed by a research
group led by Professor Takao Someya and Associate Professor
Tsuyoshi Sekitani of the University of Tokyo, who run an
Exploratory Research for Advanced Technology program sponsored by
the Japan Science and Technology Agency, in collaboration with
Siegfried Bauer's group at the Johannes Kepler University Linz,
Austria.
The circuits are extremely lightweight, flexible, durable and
thin, and conform to any surface. They are just 2 microns thick,
just 1/5 that of kitchen wrap, and weighing only 3g/m^2, are 30
times lighter than office paper. They also feature a bend radius
of 5 microns, meaning they can be scrunched up into a ball,
without breaking. Due to these properties the researchers have
dubbed them "imperceptible electronics", which can be placed on
any surface and even worn without restricting the users movement.
The integrated circuits are manufactured on rolls of one micron
thick plastic film, making them easily scalable and cheap to
produce. And if the circuit is placed on a rubber surface it
becomes stretchable, able to withstand up to 233% tensile strain,
while retaining full functionality.
"This is a very convenient way of making electronics stretchable
because you can fabricate high performance devices in a flat state
and then just transfer them over to a stretchable substrate and
create something that is very compliant and stretchable just by a
simple pick and place process."
In the future, the group would like to expand the capabilities of
these circuits and open a wide range of new applications, from
health monitoring systems, wearable medical instruments, and even
robotic skins.