Oh, just in case someone is wondering.
LCD TVs are very similar to Laptop computer displays. The fluorescent tube type (typical or ordinary type) have a white reflective layer of plastic on the back of the LED screen that reflects the tiny fluorescent tube light evenly against the back side of the LCD display. The display is hence back-lit with a relatively even light. Some displays have one tube (on the bottom or the top)and others have two (one on top and one on the bottom). Sometimes these will create a slight shadow if there is only one tube or if one of the tubes burns out. Generally these produce an adequate picture when viewed straight on and have been on the market for MANY years.
In an LED/LCD display there is an array of tiny LEDs behind the display. These are lit individually and correspond with the picture on the screen so that they are on and off depending on the display. Areas of the display that are black will hae the corresponding LED behind it turned off so that the black area is truly black and not just blotted out by the liquid in the display which creates sharper, more defined and deeper blacks. Other hues also have corresponding LEDs lit or not depending on the hue. A gray area or a dark blue area may only have half the LEDs lit and so forth. That is why the LED/LDC pictures are richer and sharper.