What technology is the TV based on?
OLED works without back-light, unlike LCD and LED. Thus it may show deeper black levels, and it's usually lighter and thinner than a LCD. In low ambient light, such as a dark room, the OLED screen achieves a higher contrast ratio than a LCD.
Plasma TVs are thin and lightweight and capable of being mounted on a wall like a painting. Their main advantage toward LCD is that they are capable of showing a more intense black.
LCD stands for Liquid Crystal Displays. It is a flat panel technology which uses liquid crystals sandwiched between two glass plates. These TVs can be even thinner than plasma screens and they normally use less energy. LCD-technology is one of the most common techniques today.
LED are newer versions of LCD TVs that use light-emitting diodes as back-light. This allows them to show black and dark colors more intensively.