In a fast-rising convergence of functional plastics and
electronics, a flexible OLED (organic light-emitting diode) on foil debuted
this week on a LeMans race car.
The technology moved out of the lab as part of a
multi-company, multi-university effort that incubated in the Holst Centre, an independent
open-innovation R&D community in Eindhoven, The Netherlands. The OLED
technology innovation was part of a trend toward pre-competitive engineering collaboration
in which major companies can avoid risk, but still profit from their inventions.
"One of our targets has been to make OLEDs twice as
efficient as they had been previously," says Paul Blom, scientific
director of the Holst Centre. Experts feel that once the technology is
optimized over the next three years, these lightweight, flexible devices will
use as much as 70 percent less energy than currently used, conventional light
In a demonstration project, OLEDs were embedded in a
carbon-fiber-reinforced plastic composite used to make side mirrors on a car
from the French racing team Oreca, which finished fourth in the 24-hour French
competition, also known as the "Grand
Prix of Endurance."
"You can easily integrate OLEDs into three-dimensional
structures, unlike other types of lighting," says Bernhard Sailer, a global marketing
manager of Huntsman Advanced Materials,
one of the participants in the Holst project. Huntsman developed new barrier
technology to help prevent the development of black spots caused by penetration
of water into the functional polymer layers.
Pierre Seze, composite department manager at Oreca, says:
"The integration of the OLED system in our carbon fiber pre-preg represents
several advantages for our race car. The first one is the weight. This
technology fit perfectly with the very demanding constraints of endurance race
such Le Mans 24 Hours."
Sailer said Huntsman wanted to demonstrate with the
mirror project that while OLEDs are not yet ready for prime time, they are
moving closer. He thinks commercial applications are two to three years away and
probably will begin with niche applications, such as ski boots, where buyers
are not extremely cost sensitive.
While Huntsman is pursuing a polymer approach to barrier
protection, a research team at Enindhoven University, also a Holst Centre
collaborator, is exploring the potential of plasma-enhanced deposition and
etching to provide protection for flexible electronic devices, including OLEDs.
A lab headed by M.C.M van de Sanden is exploring the optimal combination of organic
and inorganic materials that can be deposited with plasma techniques.
Another important target in the commercialization of
OLEDs is development of roll-to-roll processing technology using webs of
polymers. Testing is now taking place on the much slower sheet-to-sheet system.
Thermal sensitivity of plastics limits the process now
primarily to a very expensive polymer, polyimide. Holst researchers want to
develop roll-to-roll processes for polyethylene naphthalene (PEN), or even
other less expensive members of the polyester family.
In one major leap, a company called NeoDec that was
recently spun out of the research cocoon at Holst, says it has developed a
polymer printing technology that takes place at room temperature, theoretically
creating the opportunity to use most thermoplastics.
Some of the research projects at the Holst Centre are
funded by the Dutch Polymer Institute, an organization funded partly by the
Dutch government and partly by company and university researchers. Corporate
R&D budgets shrank due to extreme automotive cost cutting in the 1990s, and
companies agreed to conduct early research on projects such as flexible
electronics as a group.
"It began as an experiment, and after 13 years, we have
had significant success," said Jacques Joosten, director of the Dutch Polymer Institute. He pointed to two projects on flexible
electronics as examples: the plasma deposition work and a separate project
aimed at improving efficiency of polymer systems in photovoltaic cells.
The Holst Centre was set up in 2005 by IMEC (Flanders,
Belgium) and TNO (The Netherlands) with support from the Dutch Ministry of
Economic Affairs and the Government of Flanders. It is named after Gilles
Holst, a Dutch pioneer in research and development and the first director of