In the rush towards
'small and compact', thin displays with excellent visibility are
in big demand for a wide range of industrial and consumer applications,
including in the automotive, aeronautics, telecommunications and
multimedia sectors. Prior to this study, a number of polymeric materials
had been shown to be suitable candidates for use as organic semiconducting
materials in light-emitting diodes (LEDs). Polymer materials are
light and flexible and could allow the design of completely new
LED-displays with large electroluminescent areas. Improvements were
still necessary, however, before large scale manufacturing requirements
could be met.
Highly sought-after technology
The POLYLED project was carried out by a highly
complimentary and multi-disciplinary consortium, bringing together
two excellent polymer research institutes, the Limburgs Universitair
Centrum and the Max Planck Institute for polymer research, as well
as Philips, the major electronics company, and Hoechst, an important
chemical company. Their objective was to develop appropriate materials
and an industrial-scale manufacturing process for a new and better
polymer-based LED display.
Partners successfully defined an applicable range of polymers using
well-documented synthesis and characterisation methods. In addition,
a standard device geometry and a system for testing the new devices
were designed and implemented, allowing the direct comparison of
materials and processes.
Controlled procedures were set up for fabricating electroluminescent
devices on a large scale, either as single pixels or in a display
as an array of pixels, and their characterisation, both optical
and electronic. Special effects were also observed, including polarised
emission from devices with oriented polymer layers. New models were
generated and various demonstrator devices were produced, including
a 5x7 cm display and displays in various colours. The supporting
electronics for these devices were also developed.
The new devices are extremely thin at less than 1mm thick and have
no viewing angle dependence. They emit light in all the colours
of the rainbow and operate at very low voltage, between 3 and 4
volts, with high brightness. Finally, the production technology
is simple and cheap.
From laboratory to market
POLYLED's approach represented a radical
departure from conventional LED design and the results have confirmed
their devices as a groundbreaking new range of high-performance
ultra-thin, lightweight, flat and flexible display types, representing
enormous potential benefits for producers and users alike.
Philips has now set-up a new business unit in Heerlen, near Maastricht
in the Netherlands, for the development, manufacture and sale of
several polyLED models aimed at a variety of end-users in areas
including domestic and industrial appliances, electrical, audio-visual
and telecommunications equipment and automobile dashboards. The
company expects economic gains in the order of 265 million euro
over the first five years following the end of the project. The
new production line is now up and running and carrying out trial
operations. First sales are expected this year, and after a two-year
pilot operation, a full-scale production unit will start operating
with an increased production capacity.
Aventis Research and Technologies is a member of Hoechst Group and
the beneficiary of its parent company's extensive know-how in display
component production. Aventis has now launched a joint venture with
Zeneca Specialitiea, called Covion, to provide the new organic semiconductor
materials to display, electronics and optoelectronics industries.
Covion will be the components supplier for Philips. The anticipated
sales of Covion components to Philips alone have been estimated
at 65.5 million euro in the first five years following the completion
of the project.