How OLED Works

The Organic Light-Emiting Diodes (OLEDs) have very huge benefit: they consume less power and offer brighter displays than the traditional LCD (Liquid Crystal Displays) or LEDs (Light-Emitting Diodes). This article describes how the technology of OLED works and what kinds of displays might be possible.

A light-emitting organic diode is the semiconductor solid-state device. It is generally 100 to 500 nm thick. There are the designs with 2 or with 3 layers of the organic compounds. The much common is a two layer version, and therefore we’ll focus much on this version in the article.

The five vital parts of the OLED are two organic layers, cathode, anode and substrate. The substrate must support the OLED (Organic light-Emitting Diodes) and could consist of clear plastic, foil or glass. The anode is generally transparent and removes the electrons, the cathode exactly does opposite, it injects the electrons. The cathode may be transparent or may not be depending on the kind of the OLED utilized.

Organic layers are the emissive layer and the conducting layer. A conductive layer is manufactured of the plastic organic molecules. And an emissive layer is very different to the molecules than that from the conducting layer. The molecules transport the electrons from that cathode. This is where the light is emitted.

A process that is producing the light is called the electrophosphorescence. It is similar in process to the traditional LEDs. The current is passing to the anode from the cathode through those organic layers. With this, the electrons are displaced from that conducting layer and they are passed to that emissive layer. The holes are left at the displacing process to the conductive layer. The holes are passing over to emissive layer and then recombine with those electrons. While these electrons drip into those holes they produce extra energy as the light.

There are various types of OLEDs present. The most common type are the passive-matrix OLEDs and active-matrix OLEDs. The Active-matrix OLED is known as AMOLED. It consumes very less power compared to the passive-matrix OLED and also is suited well for the portable devices that are powered by the battery.
The active-matrix has pixels that are integrated onto the Thin Film Transistor (called the TFT) array to form the matrix. This Thin Film Transistor behaves as the array of switches in order to control the quantity of the electrical current that is flowing through every pixel of OLED.

The Passive-matrix OLED is called the PMOLED. They are suited well for the small devices of display like the audio players or cellular phones, since they consume much power than the active-matrix OLEDs. Power consumption is much lower than that of the traditional LCDs.

The passive matrix has columns and rows formed to the two-dimensional array. The element of the array is called the pixel. The Electrical current is passed to a thin film of the organic material and the light is produced. The brightness of every pixel demands the quantity of the current applied.