Flexible Electronics Using Organic Transistors
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Date: 05-10-2006
Start Time:
11:00am
End Time: 12:00pm
Speaker: Takao Someya
From:
University of Tokyo
Location: Interschool Lab, 7th floor, Schapiro/CEPSR
Hosted by:
Center for Integrated Science
Abstract:
Over the past several years, organic field-effect transistors (FETs)
and their integrated circuits have attracted considerable attention
since organic FETs possess attributes that complement silicon-based LSI
devices. Organic FETs can be manufactured on plastic films at low
(ambient) temperatures by printing processes; therefore, they are thin,
lightweight, mechanically flexible, and potentially inexpensive to
manufacture. Recent studies of organic FETs are driven by flexible
displays and radio frequency identification (RFID) tags. As the third
application, we have proposed and demonstrated flexible, large-area
sensors and actuators in which organic FET active matrices are used for
data readout from area-type sensors or to drive large-area actuators.
In this talk, I report recent progress, issues, and future prospects of
organic FET-based flexible, large-area sensors and actuators. The first
example of large-area sensors is an electronic artificial skin
(e-skin). Among area sensors, sensing of a touch is important for
robots in the next generation. An artificial skin integrating pressure
sensors and peripheral electronics using organic FETs is fabricated for
the first time based on the scalable circuit concept. In particular,
moving images of pressure have been taken by a flexible active matrix
with organic transistors whose mobility reaches as high as 1.4 cm2/Vs.
The transistor is electrically functional even when it is wrapped
around a cylindrical bar with a 0.5 mm radius. Then, I report on a
large-area, flexible, and lightweight sheet image scanner on a plastic
film integrating high-quality organic field-effect transistors (FETs)
and organic photodiodes. Organic photodetectors distinguish between
black and white from the difference of reflectivity between black and
white parts on paper. The sheet has no optical or mechanical parts and
therefore very thin and lightweight. Organic FETs are also suitable for
applications to large-area actuators. We have fabricated a novel,
flexible, lightweight sheet-type Braille display that is fabricated on
a plastic film for the first time by integrating high-quality organic
FETs with plastic actuators. A small hemisphere that projects upwards
from the rubber-like surface of the display is attached to the tip of
each rectangular actuator.
Takao Someya received the Ph.D. degree in electrical engineering from
the University of Tokyo, Japan, in 1997. From 2001 to 2003, he worked
on organic electronics in the Nanocenter (NSEC) of Columbia University
and Bell Labs as a Visiting Scholar. Since 2003, he has been an
Associate Professor of the Department of Applied Physics, University of
Tokyo. His current research focus is on organic transistors, flexible
electronics, plastic circuits, and molecular scale electronics. He is
an IEEE/EDS Distinguished Lecturer since 2004 and a recipient of 2004
IEEE/ISSCC Takuo Sugano Award. Since 2003, the number of press coverage
has been more than 200, which include BBC, The Washington Post, The
Economist, Scientific American, and National Geographic Magazine. His
“large-area sensor array” electronic thin film was featured in Time
Magazine as one of its “Best Inventions of 2005” in its November 21st
issue.