Plasma display technology

A plasma display is a type of flat-panel screen that creates a picture using a grid of tiny cells, each containing a small amount of inert gas. When a voltage is applied across a cell, the gas ionises into a plasma and emits ultraviolet light, which strikes a phosphor coating and causes it to glow in red, green or blue. Each pixel is made of three such sub-cells, and by varying how strongly each is driven, the panel produces a full range of colours. Because every cell generates its own light, a plasma panel needs no backlight.

This self-emitting design gives plasma displays good contrast and the ability to show deep blacks, since unlit cells emit no light. They also offer wide viewing angles and fast response, which made them popular for large high-definition televisions during the era when flat panels replaced bulky cathode-ray-tube sets. Plasma panels were typically built in larger screen sizes, where their picture quality was competitive.

The main alternative is the liquid-crystal display (LCD), often using thin-film-transistor (TFT) addressing. An LCD does not emit light itself; instead a backlight shines through a layer of liquid crystals that twist to let more or less light pass, with colour filters producing the image. Plasma generally excelled at contrast and motion, while LCDs offered lower power consumption, lighter weight and freedom from the risk of image retention, and LCD eventually became the dominant flat-panel technology.

Frequently asked questions

How does a plasma display make light?

Each pixel cell contains an inert gas that is ionised into a plasma by an applied voltage. The plasma emits ultraviolet light, which excites phosphors that glow in red, green or blue.

How does plasma differ from an LCD?

A plasma panel's cells emit their own light, while an LCD uses a backlight shining through liquid crystals. Plasma generally gave deeper blacks, whereas LCD used less power and was lighter.

Why do plasma panels show good black levels?

An unlit plasma cell emits essentially no light, so dark areas appear genuinely dark, giving high contrast compared with backlit displays.