The main difference between smart LED TV and LCD is regarding the back-lighting. LED TV’s use an array of tiny and efficient LED (light emitting diode) to get the screen illuminated whereas the ordinary LCD TV's make use of the cold cathode fluorescent lamps for back-lighting. Due to this change in back-lighting technology LED TV’s have an edge over the simple LCD television.
LED stands for Light Emitting Diode Television. It can also refer as LCD televisions with LED technology. The technique of image formation remains the same in both the cases. However, instead of using the technology of CCFL, it uses the LED technology for back-lighting. In this case, light emitting diodes are used. LED technology consumes less energy and space than conventional bulbs. LED TVs are of two types- Edge-lit LED TVs and back-lit LED TVs.