Off on a family holiday, Mum and Dad in the front of the car, kids in the back happily watching TV? Mounted on the back of the front seat is a wafer thin screen on which they can watch their favourite cartoon characters. When they arrive at their hotel, Dad removes the screen, rolls it up and, once inside, he pins it on the hotel room wall and the show goes on. Science fiction? In the foreseeable future, it won’t be.
The key to this revolution is organic light-emitting diodes (OLED) and a new material developed by scientists at Bayer. Baytron P is an electrically conductive plastic which extends the working life of the diodes and has made it possible to make screens so thin and flexible that they can be rolled up.
The phenomenon of electrically luminescent organic materials has been known for half a century. But the material used then proved to be too unstable and the light yield was so low that no thought was given to any practical applications.
Then, five years ago, Bayer scientist Rolf Wehrmann and his colleagues made a breakthrough. They had been given the task of finding organic substances from which light-emitting, wafer-thin and flexible film could be made. The objective was to make flat screens no longer dependent on projection from the back as text and pictures appear thanks to organic diodes.
The transparent Baytron P they developed increases the working life of light-emitting diodes dramatically. A 10,000 hour, non-stop test of the brightness of a computer monitor was passed with ease. Already, companies like Philips are using Baytron P to develop the screens of tomorrow – super-thin, made entirely of plastic and safe because of the low voltage used.
But its not just Bayer who are getting in on the organic act. For their part, Eastman Kodak, Sanyo Electric Co and Ulvac Japan recently inked a three-year agreement to jointly develop equipment for the manufacture of OLED flat panels.
Prior to that, in February `99, Kodak and Sanyo had agreed to jointly develop a next generation of OLED displays, and unveiled a model of a full-colour, active matrix organic electroluminscent (OLED) display at the Japan Electronics Show. The 2.5-inch (measured diagonally) display featured a 190,000-pixel display panel.
OLED displays are easier to view and have lighter weight and lower power consumption than liquid crystal displays (LCDs).
An organic electroluminescent (OLED) display comprises thin layers of individual carbon-based (hence `organic’) elements that emit light when electric current is passed through them (electroluminescence). Each of these pixels can be turned on or off independently and can create multiple colours and a fluid, smooth edged display.
OEL displays are self-emitting, requiring no backlight, and are therefore very thin and have low power requirements. They also provide a very wide viewing area, approximately 160 degrees, far superior to other available flat panel displays.
Telephones with the displays are already on the market, and Video recorders, cellular phones, watches and CD players will follow soon. In the long term, Philips plan to build navigation systems and car instrument panels. And Sanyo will soon replace many of the LCD screens found on digital video cameras and personal digital assistants (PDAs).
And the TV screen at the back of the family car? `We should be there in 10 years,’ Philips’ Jan Robert Visser confidently predicts.
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