PLED

One of the most intriguing recent developments in the display industry has been the discovery and development of polymer light emitting diodes (PLEDs). It all started in the Cavendish Laboratory of Cambridge University in 1989, when it was found that ‘organic’ LEDs could be made using conjugated polymers.

In particular, polyphenylene vinylene (PPV) was found to emit yellow-green light when sandwiched between a pair of electrodes. The initial device efficiencies were very low, but the researchers quickly realized the commercial potential of this discovery, especially for the manufacture of displays which emit their own light. These would offer significant advantages over the main display technology used today (liquid crystal display or LCD), in which a separate light source has to be filtered in several stages to produce an image.

PLEDs have a number of intrinsic advantages over liquid crystal devices. PLED is an emissive technology: it emits light as a function of its electrical operation. A PLED display consists of polymer material manufactured on a substrate of glass or plastic, and does not require additional elements such as backlights, filters and polarizers. PLED technology is very energy efficient and lends itself to the creation of ultra-thin lighting displays that will operate at lower voltages. The resulting benefits include brighter, clearer displays with viewing angles approaching 180 degrees; simpler construction resulting in cheaper, more robust display modules, and fast response times allowing full color video pictures even at low temperature.

Contact: Cambridge Display Technology Ltd., Cambridgeshire, UK.