1.1 What is LED
Light Emitting Diode - LED
LED is a semiconductor device that emits light on certain wavelength (colour). A die (active area of LED) is encased in plastic or ceramic housing. The housing may incorporate one or many dies.
The term SSL (Solid State Lighting) is common term for LED technology being used for lighting applications. It refers to technology in which the light is emitted by solid-state electroluminescence as opposed to incandescent bulbs (which use thermal radiation).