How does an LED work?

How does an LED work?

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LED stands for Light Emitting Diode, and this light source should not be confused with a light fixture or luminaire. An LED is a component of the entire fixture. LED lighting can also be referred to as solid-state lighting (SSL) because an LED is solid-state technology similar to the memory in your computer.

LEDs consists of four main parts: die, substrate, phosphor and lens. The LED die is a semiconductor device made of gallium nitride (GaN). When electric current passes through the die, it emits blue light. One or more die are then mounted to a substrate commonly made of aluminum or ceramic. This allows easier integration of the LED into a fixture and provides an efficient way to bring power to the LED.

For general lighting applications, white light is generally desired, not blue. In order to achieve the target color, phosphor is used. When the blue light hits phosphor particles, they glow and emit white light. The phosphor can be applied to the die directly, or it can be mixed into the lens material, which typically consists of silicon or glass. The lens extracts and directs the light emitted from the die.