LED,LCD and Plasma, Whats the difference?

I can explain some of the basic technology behind the kinds of screens, but I’m not sure which kinds are preferred in which situations.

All television (TV) sets emit their own light, in the form of picture elements (pixels). Each pixel is an array of red, green, and blue (RGB) lights packed tightly together.

A light-emitting diode (LED) emits light of a specific wavelength when you pass a current through it, creating any of the RGB colors.

Liquid crystals are an unusual phase of matter between solid and liquid. Liquid crystal displays (LCDs) use certain materials with unusual optical properties when electrified. They can act as either shutters or reflectors to adjust the brightness of light in a certain direction. LCD’s, however, do not emit light themselves, so they must be used in conjunction with LEDs or other light sources behind, or reflecting off, the LCD elements.

LCDs are also used in electric goggles that come with 3-dimensional (3D) TVs (unlike the cheap polaroid glasses you get at the movies). The goggles rapidly alternate between left eye and right eye in synch with the tv, so at any instant one lens is transparent and the other opaque.

A plasma is the so-called 4th state of matter—a gas so hot that all the atoms are ionized because they can’t hang on to their electrons. Fluorescent lights contain plasmas. With the right gas mix & high voltage, a plasma can emit specific RGB colors, engineered into small pixels like LED displays.

There’s another technology called DLP (digital light processor) that involves an array of tiny mirrors, one per pixel, each just a few microns in size and controlled by a piezo-electric movement, each mirror either reflecting toward or away from a target axis. By switching on & off thousands of times per second & adjusting how often it’s on, brightness is adjusted. That’s how digital projectors in movie theaters work.

Hope that helps.

@gasman explained better than anyone could try.

I’ll just tell you another difference: PRICES.