A polymer LED is an LED made from polymer. Also known as polyLED or PLED.

I should warn you I am about to get technical now, sorry, it's my job....

It is a form of organic LED (OLED). OLEDs are formed by vacuum deposition of a stack of small molecule materials. Commonly they consist of more than seven layers, and are very hard to make upward emitting, so they emmit back down through the substrate.

Polymer LEDs (or polymeric LED, not polymorphic leds although they would be great too) are made using long-chain molecules. These have the benefit that they are much more chemically stable, and so can be deposited much more easily. Typically this is done by spin-coating or ink-jet printing. They are a form of conductive polymer called a conjugated polymer. These light emitting polymers (LEP) are licensed from Cambridge display technology (CDT) and developed by several companies including Philips.

The most likely use for polymer LEDs are for displays. In this application OLEDs and PLEDs are essentially interchangeable as they have very similar electrical properties.

OLED displays can offers some desirable benefits over LCDs. They may be thinner and brighter with wider viewing angle and instant response speed (the end to motion blur). And could offer superior colour saturation.

However you should always be asking about lifetime, both of the display substrate and the light emitting material.

The cost could also be cheaper, however this is as yet unclear. They do not require LCD material or cell making, but do require many other specialist technology steps.

One problem that is glossed over by some reports, and dealt with just plain incorrectly by others, is daylight readability. Most OLED displays are essentially a light emitting mirror. And with daylight some two to three orders of magnitude brighter than the light being emitted, will you see an image at all if you take the display outside?

As well as lifetime there is also a question over whether OLEDs offer enough of a benefit over LCD. OK, so they may be slightly better in some aspects, but they are worse in others. Anything that is worse in ANY respect presents a problem. And remember that OLEDs are still YEARS away from being a commercial proposition, years during which LCD will develop quickly, fuelled by their own commercial turnover.

However EVERY major (and minor) displays and electronics manufacturer and reseller have an interest in OLEDs and are feverishly developing the technology. With this much money in the area, can any of them afford to fail? You might say that whether or not it is technologically superior it will have to succeed.

Whatever may happen, do not believe the hype. Ask searching questions of any demonstrator sold to the press as a product that is just round the corner...