QLED meaning: the TV, which uses some form of the backlight to light up the picture. QLED and LCD both work on the same process. If the black light is not working, there won't be any display of pictures in both of these. The difference in both of these is just how they display filter light. In LCD or LED, a blue light coated with a layer of phosphorus is produced by the black light, which turns the light white. That white light gets filtered with an RGB filter, which produces all the colors needed on display.