White LED technology structure and white light source. For general lighting, white LED is usually formed in two ways in terms of process structure. The second method is a mixture of monochromatic light. Both of these methods have succeeded in producing white optical devices. LED GaM chips emit blue light (p=465nm), which is packaged with YAG (yttrium aluminum garnet) phosphor. When the phosphor is excited by the blue light, it emits yellow light. The second method USES chips with different colors of light, which are combined to produce white light.