There are plenty of different screen types out there, all working in different ways to produce the same results. Each technology has its own unique strengths and weaknesses, so here are some basics to consider when looking for the right 4K TV for your needs:
LED TV: Direct LED
These displays are backlit by an array of LEDs (light emitting diodes) directly behind the screen. This enables localised dimming – meaning immediately adjacent areas of brightness and darkness can be displayed more effectively – and greatly improves contrast. LED TVs are also more power efficient and capable of a wider colour gamut than CCFL sets. Because of the extreme cost of mounting these arrays of LEDs, cheaper TVs usually use Edge-Lit LED screens over Direct or Full-Array LED screens.
LED TV: Edge LED
With these TVs, LEDs of the backlight are mounted along the edges of the panel. This arrangement enables radically slender displays and offers superior contrast levels to CCFL, but can't achieve the same picture quality as directly lit LED sets. However, they do come in far cheaper which is why most LED TVs out there now use this technology.
OLED TV
The backlighting on OLED (organic light emitting diode) sets is achieved by passing an electric current through an emissive, electroluminescent film. This technique produces far better colours and higher contrast and also enables screens to be extremely thin and flexible. This is the holy grail display technology and LG, Sony, Philips and Panasonic have all adopted it in their flagship sets.
Quantum Dot
Quantum Dot is Samsung's big play in the LED TV space. With it, the brand claims that it's able to produce more colorful pictures than LG and Sony while offering even brighter panels. LG's Super UHD TVs all use a variation of Quantum Dot called Nano Cell, and Hisense makes a number of Quantum Dot TVs for the US and China.