How does an lcd tv work ?

LCD or Liquid Crystal Displays have come a long way from digital watch displays. In an LCD TV,  these are crystals in a plastic material sandwiched between plates of polarized glass (think of polarizing sunglasses).  LCD tvs get their light from behind the glass panels.  The function of the LCDs is to either block a tiny spot of light or allow it to pass and thus be seen by the viewer.  A small area of electric current turns on or off the transparency of the corresponding spot of the LCD display.  The sum of all these spots, or pixels, is the display you see.  

LCD’s  have a slim design and a flat viewing screen. LCD TVs are much lighter than a comparable Plasma screen TV and are much more sturdy as well. However, at present,  they are also much more expensive than a comparable plasma model.  Because LCD technology does not require extra electrodes to stimulate phosphores, as in plasma TVs, the panels are thinner and require less power to operate than plasma TVs.

The only thing that comes from an LCD tv is the viewing picture light, thus the LCD technology is non-emissive - meaning it does not give off radiation.