Organic light emitting diode televisions or the OLED TVs are television sets in which light emitting diode or light emitting polymer are used. The organic light emitting diode is any kind of light emitting diode having an emissive electroluminescence layer that is composed of a film of organic compounds. This layer contains some polymer substance which allows suitable organic compounds to be deposited. The deposits appear into rows and columns forming a flat carrier by a simple printing process. This results into a matrix of pixels which can emit light of different colors.
These systems can be used in television screens as well as computer displays and other small and portable screens like the cell phones and even PDAs. They are also extensively used in advertising and indication. In addition to theses, OLEDs are used in various light sources for general illumination as well as large area light emitting elements. Generally, they produce less light per area as compared with the inorganic LEDs which are solid state based and are mainly designed for point – light source applications.
The main benefit of the organic light emitting diode televisions over the traditional liquid crystal displays (LCDs) is their ability to function without a backlight. These devices do not require a backlight to function and therefore draws far less power that their LCD counterparts and other form of televisions. Because of this, they can operate for a long time even when powered from a battery. Again, because of this ability to operate without backlight, the display for the OLEDs can be much thinner than that of their LCD counterparts. However, they have one main limitation; their materials degenerate quite rapidly thus limiting their use.
The electroluminescence in organic materials was first produced in early 1950s by Bernanose and company workers at Nancy University in France, by the application of high voltage alternating current in air to quinacridine and acridine orange which is either deposited on or dissolved in cellulose or thin films of cellophane. The first attempt at creating a polymer LED was however made by Rodger Partridge at the National Physics Laboratory of the United Kingdom, a project which succeeded and was later patented in 1975. However, its publication delayed until 1983.
A typical OLED consists of a conducting layer, an emissive layer and three terminals of substrate, anode, and cathode. The organic molecules that make up the layers conduct electricity and have conductivity levels which range from insulators to conductors. In this respect, OLEDs are considered to be organic semiconductors.
The different manufacturing processes give OLEDs many advantages over the flat panel displays which are made from LCD technology. Firstly, the OLED televisions have significantly lower cost than the plasma displays. They also enable a great range of colors, contrast, brightness as well as the viewing angle as the pixels emit light directly. Furthermore, OLED colors appear more correct and un-shifted even with viewing angle approaching 90 degrees from the normal. Most importantly, OLED televisions save a lot of energy.