How OLEDs work

Measuring just 3mm thick, OLED displays are changing the face of our TVs and mobile phones

TVs have come a long way since the massive boxes hogging the corner of your living room. Yet even your current fl at-screen LCD TV will soon look unwieldy compared to the next generation of products. With OLED (organic light-emitting diode) technology TVs, computer monitors, mobile phones and pretty much anything else with a screen are set to become thinner than ever before.
OLED is a major step on from the LCD technology that is currently used. In simple terms, it is created from organic materials that emit light when power is passed through it. An OLED display contains thin films of organic materials placed between two conductors; as the current passes through, the display lights up. This self-illuminating function removes the need for the backlight that is an essential requirement of a traditional LCD screen. There are two kinds of OLED display, of which AMOLED (active matrix) is the most important. Designed for larger displays (over 7cm/3in), it allows for each individual pixel on the screen to be controlled separately.
The three key benefits to OLED displays all stem from that lack of a backlight. The immediate consequence is that devices can be made thinner – a 100cm (40in) LCD TV needs a backlight large enough to span and light the entire surface of the screen evenly. Without this problem, the same sized OLED-based TV could be little more than a few centimetres thick, and as miniaturisation of the three components powering devices develops further, they will only continue to get thinner.

The next benefit is that without that backlight, the screens draw far less power. While a black image on an LCD display is backlit to the same degree as a white screen, the light on an AMOLED display directly corresponds to the brightness of each individual pixel. For devices that run on battery power, like mobile phones, this is a massive boon.
The final benefit comes in the form of a massive improvement in image quality, with greater contrast between light and dark colours thanks to the absence of the backlight that turns blacks into dark greys on a traditional LCD.
Of course, the thinner hardware is only the first step in what OLED technology will bring us. Through nanotechnology companies like Sony and Toshiba have created screens that measure less than half a millimetre thick, making them extremely flexible. Imagine a mobile phone with a large screen that can be folded to keep it pocketable, or even wearable computers built into clothing – this is no longer just the stuff of science fiction.