What is LED Blacklit Display?

Answer 1

Liquid Crystal Displays (LCD's) do not emit any light of their own. They work by blocking or allowing light to pass through individual cells, by twisting a liquid crystal held between two membranes, using low voltage and polarising filters.

Unlike the old Cathode ray Tubes (CRT's) and Plasma screens, which actually produce light at the source of the pixel, or picture element.

Up until recently, the best way to make an LCD light up was to use very thin, glass, fluorescent tubes, arranged around the edge of the screen and using special plastic filters, to spread the light evenly behind the LCD panel.

These 'Cold Cathode Fluorescent Lamps' (CCFL) need a high voltage inverter, to make them strike across and light up. They are very delicate, the inverter uses a lot of power and they run quite warm. But they do produce a lot of clean, white, pure light.

Light Emitting Diodes (LED's) Run on low voltage, run cool and can now be made very bright, very white, very tough and cheap. So they make a good replacement for CCFLs.

For a long time, LED's could only be made in certain colours, red being a favourite for brightness, due to the Gallium Arsenide doping used in the semiconductor layers. Other colours were quite dim and very expensive to make.

Technology has now caught up and LED's can be made, which give out white light and very bright. Modern flashlights and car lighting has only recently, been able to use this new technology.

So LED backlighting is a new replacement for the old tubes. LED's are tougher (being made of solid plasic), use less power (saving the planet) and run cool.

They can also now be made to be brighter than CCFLs and so produce a brighter picture, in daylight viewing conditions.