LEDs are known as Light Emitting Diodes. Light-emitting diodes are made up of using semiconductors such as Gallium Arsenide, Gallium Phosphide, and Gallium Nitride, have been around since the late ’50s. The main application of LEDs are indicator lamps, calculators, large advertising signs with high brightness. Limitation of LEDs Though such crystalline LEDs are not inexpensive, but it has its own limitation like integrating them into small high-resolution displays. L.E.D.’s work well in giant screens and advertising displays like those in Times Square, they cannot easily be used to create small, high-resolution screens for portable computers.
Organic LEDs – A breakthrough in LED technology
To overcome the difficulties faced by the conventional LEDs, the Organic LEDs has entered into the field. Organic light-emitting devices (OLEDs) operate on the principle of converting electrical energy into light, a phenomenon known as electroluminescence. They exploit the properties of certain organic materials which emit light when an electric current passes through them. In its simplest form, an OLED consists of a layer of this luminescent material sandwiched between two electrodes. When an electric current is passed between the electrodes, through the organic layer, light is emitted with a color that depends on the particular material used. In order to observe the light emitted by an OLED, at least one of the electrodes must be transparent. Advantages of OLEDs When OLEDs are used as pixels in flat panel displays, they give greater viewing angle, lighter weight, and quicker response. Since only the part of the display that is actually lit up consumes power, the most efficient OLEDs available today use less power. Because OLEDs are self-luminous, backlights are not required as in liquid-crystal displays (LCDs). OLEDs have very low power requirements and are thin, bright and efficient.
Applications of OLEDs
OLEDs have been proposed for a wide range of display applications including magnified microdisplays, wearable, head-mounted computers, digital cameras, personal digital assistants, smart pagers, virtual reality games, and mobile phones as well as medical, automotive, and other industrial applications. This OLEDs with its full color displays will replace today’s liquid crystal displays (LCDs) used in laptop computers and may even one day replace our ordinary CRT-screens.
Future scope of OLEDs
In OLEDs as crystalline order is not required, organic materials, both molecular and polymeric, can be deposited far more cheaply than the inorganic semiconductors of conventional LED’s. Patterning is also easier, and may even be accomplished by techniques borrowed from the printing industry. Displays can be prepared on flexible, transparent substrates such as plastic. These characteristics form the basis for a display technology that can eventually replace even paper, providing the same resolution and reading comfort in a long-lived, fully reusable (and eventually recyclable) digital medium.