Plasic TV Technology Backgrounder

	The Plastic Television Technology Backgrounder
16th Feb 1998

The announcement of the world's first video display based on light emitting polymers (LEP) is truly historic. The collaboration between CDT and Seiko-Epson (SEC) brings together three diverse technologies to create the first of a new generation of displays:

CDT, the inventor of LEP brings its world-leading expertise in this field. SEC brings its state-of-the-art active matrix backplane and ink-jet printing technologies.

Together, this radical development uses the unique processing potential of polymeric semiconductors to ink-jet print the active picture elements (Pixels) of the display directly on the top of the pixel swithcing element in the active matrix.

This means that the performance characteristics of LEP: Wide view angle, fast switching, robust solid state devices can be used in a flat panel display that combines the look and feel of traditional CRT with the thinness and lightweight necessary for the next generation of displays.

Although the display shown today is small (measuring 50mm on the diagonal), it has extremely high resolution and is capable of displaying a full NTSC television picture. This shows the high resolution that is possible with this technology.

The processing techniques used in making this prototype are scaleable, which means that the steps from making a single colour small display to making a full size full colour display are already demonstrated. This has allowed CDT and SEC to predict demonstration of a full colour demonstrator later in 1998.

There are a host of reasons, technical and commercial, that make LEP the prime candidate for the next generation of flat panel displays:

LEP Feature	Display Screen Benefit
The processability of the polymer materials - especially in this case the ability to ink-jet the active materials of a device.	This will considerably simplify the manufacturing process.
The fact that a large number of process steps are common with LCD manufacture means a lot of existing manufacturing plant can be used in LEP manufacture.	Reduces cost and risk to the manufacturer
LEPs are self emissive which means that a large number of components used in an LCD such as polarisers, colour filters and backlights are not needed.	This reduces cost and has other benefits for the overall thickness and weight of the LEP display which are considerably reduced.
LEPs are Lambertian emitters	The displays show a 180 degree viewing angle up, down and side-to-side
LEPs are driven by low DC voltage	Voltages are suitable for use with TFT active matrix drivers. It is also important for portable applications, as no voltage converters are required.
The LEP and TFT switch very fast	The display can show true video, without the blurrig and submarining seen on LCDs.
The finished devices are solid state	Very rugged and robust - ideal for portable environments. This also saves weight and overall thickness in the product packaging.