OLEDs (Organic LEDs) are one of the latest developments entering the optoelectronics arena. The ability to use organic compounds in LED usage is the wave of the future and as always, VCC is following the development of this field. Below we are going to cover some of the main questions concerning OLEDs including their composition, operation, usage, benefits and disadvantages.

What are OLEDs?

OLEDs are Organic Light Emitting Diodes. Kodak was the first to develop this Technology that uses organic compounds such as glass and plastic to compose the emissive electroluminescent layer. This layer is no thicker than a film and is applied in a process that is simple, low cost and requires fewer materials than other LED compounds used to emit light and provide full spectrum color displays.

What types of OLEDs are there?

There are three basic types of OLEDs being developed and implemented. Those types are:

• Small Molecule OLED – Known as SM-OLEDs, these devices are typically made from glass substrates and are deposited through a vacuum process. The SM OLED is more efficient than the other types and can be evaporated allowing for complex multi-layer structures. The drawbacks with the small molecule OLED is that it is not flexible and the vacuum process is more expensive than other OLED types. Newer developments with stacked and flexible plastic substrates are removing the disadvantages and this product is expected to have large impacts in the future of OLED installations.
• Polymer OLED – Also called Light Emitting Polymers (LEP), this OLED type is generally composed of a plastic compound that forms the electroluminescent conductive layer. The process for depositing the materials in this layer is a precision ink jet application. This process is low cost, simple and can be created with multiple levels to improve efficiency. Once applied, it is extremely flexible. The drawback with the Polymer OLED is that current efficiency is not at the level of the SM OLED, however, it has surpassed LCD efficiency levels.
• Phosphorescent OLEDs – This OLED type has up to four times higher efficiency than that of a conventional fluorescent OLED. Its application process is the same as the Polymer OLEDs as it is applied by precision ink jet printing, however, it is highly efficient in converting electrical energy. Recent developments are assuring the future success of this OLED type.

The Future of OLEDs

Many different versions of these main OLED types are entering the market. They offer a full color spectrum that is thin and flexible. Future displays using OLEDs will be flexible, low cost, brighter and more efficient. OLEDs also have a wide viewing angle with high contrast video capabilities. This technology is expected to result in displays less than 1mm thick.