LED's

LED’s are semiconductor devices, containing a p-n junction. When current flows through this junction the recombination of an electron and a hole results in the emission of a photon. The emitted light can be in the infrared, visible or near UV range.

LED’s have undergone large improvements in color, power per LED and efficiency in recent years and more improvement is to be expected in the coming years. The luminous efficacy of white production LEDs reaches up to 70 lm/W. Prototypes have reached 150 lm/W.

LED’s still have disadvantages: their maximum junction temperature is only 100°C, so adequate heat sinking is required. The maximum power per LED is still very limited to some Watts, requiring a lot of devices to compete with fluorescent or MH /HID lamps. And LED’s are still expensive compared to other light sources.