White light

Nichia Corporation and Citizen Electronics have formed an alliance that will allow Citizen to package and sell Nichia’s white LEDs.

Citizen Electronics will purchase production quantities of Nichia indium gallium nitride (InGaN) die for the manufacture of the LEDs.

Nichia developed the white LED in the mid-1990’s.

Nichia found that when blue light from an InGaN die passes through a thin phosphor coating, a portion of the blue light is down-converted to yellow light. This yellow light mixes with the remaining blue light from the InGaN die to create bright white light.

Subtle variations in the phosphor coating vary the tint of the white light from a bluish-white to a yellowish-white. For that reason, the packaging step is critical in order to maintain both colour consistency and quality of the finished white LED.