WHITE LIGHT FROM LIGHT EMITTING DIODES

摘要

Solid State Lighting (SSL) becomes feasible after blue and green Light Emitting Diodes (LED) joined the red LED, made in large numbers mostly for signaling for many years. Very recently the efficiency values for the (In,Ga)N based blue and green LED approached the values common for high power transparent substrate (TS) (Al,Ga,In)P diodes. Besides combinations of blue, green, and red LED chips in one LED lamp - multi-chip (mc)LED -conversion of blue or UV LED emission into white-complements appears to be a viable alternative - phosphor converted (pc)LED. The simplicity of this approach is paid for by efficiency losses, which eventually will decrease to about 30% with more development work put into the issue.