What is an LED and how do LED screens work?
05.04.2018
The term LED has entered the day-to-day lexicon thanks to the ever-more widespread use of this technology, but do we really know it means? Here we will try to explain how this technology works, in layman's terms.
Historical Background
LED stands for Light Emitting Diode. A diode is an electronic component – initially tubes, now semiconductors – which allows electric current to flow in one direction only. In short, it is what makes the light given off by the passage of current visible.
Although research into photoluminescence dates back to the early 20th century, it wasn't until 1962 that the first LED was developed by American inventor Nick Holonyak Jr. Initially, these electronic components were costly and only available in red and were used in a limited range of devices. Over the following years, however, the range of colours and uses grew, leading to a lowering of cost barriers and allowing LED technology to eventually dominate in an enormous range of sectors.
In the 1990s, white LEDs became available, and around a decade later they would begin to take over from traditional incandescent and halogen lights, thanks to their excellent colour rendering and significant energy savings. This also gave rise to the gradual replacement of streetlights and traffic lights, as well as domestic and office lighting, allowing local authorities, homeowners and businesses to make significant savings on their energy bills.
LED Technology in Displays
The LED screen is a flat panel which uses a series of light emitting diodes (LEDs) as pixels. The first LED display was created in 1968 by a group of researchers and engineers. It took a few years to develop this into a high-quality finished product, both in terms of colour rendering and the clarity of the images or text displayed on even large displays (maxi-screens and LED walls).
On the technical level, there are two methods of using LED technology in displays. The first, known as Edge lighting, is the most common, and consists of positioning the LEDs at the edges of the monitors, making it suitable also for ultra-flat screens. Full-array backlighting, on the other hand, offers greater contrast and deeper blacks, but with the trade-off of higher production costs due to the large number of LEDs evenly distributed inside the panel.
Regardless of these technical details, LED screens, as well as being longer lasting and more economical to run, are undoubtedly able to provide better images and colours, making it the technology of the moment both in domestic (e.g. television sets, smartphones and computers) and commercial environments (shop signs, advertising maxi-screens, perimeter screens for sports stadiums).