Cambridge Display Technology

The term nanotechnology is widely used today, and P-OLED technology can certainly be thought of as an example. The total thickness of all layers in a P-OLED display device can be less than 500nm, so that in effect, the thickness of a display is determined mainly by the thickness of the substrates – usually glass – that form the top and bottom of the device.

The story started at the Cavendish Laboratory of Cambridge University in 1989, when it was found that organic LEDs could be made using conjugated polymers. In those early experiments, 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 researchers quickly realised 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 we still use today (liquid crystal display or LCD), in which a separate light source has to be filtered in several stages to produce the image we see.

P-OLED advantages

P-OLEDs have a number of intrinsic characteristics:

• P-OLED is an emissive technology: it emits light as a function of its electrical operation.
• A P-OLED display consists of polymer material manufactured on a substrate of glass or plastic, and does not require additional elements such as backlights or filters.
• P-OLED technology is energy efficient and operates at low voltages.
• P-OLED materials can be processed in solution, allowing manufacturing techniques such as ink jet printing to be used; this has many advantages over vacuum deposition methods.

The resulting benefits include brighter, clearer displays with very wide viewing angles, simpler construction offering the potential for cheaper, more robust display modules and ultra-fast response times allowing full colour video pictures even at low temperature.