Display devices today no longer feature the same bulky and wide design as they did in the past. Rather, most of them feature a slim and low-profile design. Known as flat-panel displays, they are found in smartphones, tablets, monitors, TVs, human machine interfaces (HMIs) and other devices. While all flat-panel displays feature a slim and low-profile design, however, there are several types of flat-panel displays available.


The most common type of flat-panel display is liquid-crystal display (LCD). LCD displays are energy efficient, long-lasting and produce high-quality images. As their name suggests, they contain liquid crystals that form the pixels. The liquid crystals are housed in a thin layer. Behind the liquid crystals is one or more bulbs, known as backlighting, that illuminates the crystals.


In addition to LCD, organic light-emitting diode (OLED) is a common type of flat-panel display. OLED is unique because it’s a type of emissive display technology. Emissive means that a display is self-illuminating. In other words, the pixels within an OLED can illuminate themselves. Other types of flat-panel displays require backlighting. Since OLEDs have self-illuminating pixels, they don’t require backlighting.


Light-emitting diode (LED) is a type of flat-panel display that uses LED backlighting. Most LED displays are simply LCDs but with LED backlighting. All LCDs require backlighting because, unlike OLEDs, they aren’t self-illuminating. An LED display is an LCD that uses LED-based backlighting to illuminate its pixels.


In the past, many flat-panel displays often used electroluminescent (EL) technology. They were made with phosphor-based pixels that would glow when exposed to an electrical current. EL displays would draw a current from a connected wall outlet, at which point their pixels would glow to produce visible images.


Plasma is also considered a type of flat-panel display. While plasma displays have largely been replaced with LCD and OLED displays, they were once one of the most popular types of displays on the market. What is a plasma display exactly?

Plasma displays work by applying an electrical current to a layer of trapped gas. Most of them feature neon gas. The neon gas is trapped between two adjacent layers. When exposed to an electrical current, the neon gas will glow.