n-UV plus blue/green/red white light emitting diode lamps

Phosphor-conversion light-emitting diode (LED) lamps were fabricated by precoating blue/green/red phosphors onto near-ultraviolet (n-UV) LED chips prior to packaging them into LED lamps. With a 20 mA injection current, it was found that the color temperature, T-c, was approximately 5900K, the color rendering index, R-a, was approximately 75, and the CIE color coordinates were x = 0.33 and y = 0.35 for the "n-UV+blue/green/red" white LED lamps. No obvious changes in color temperature, T-c, or color-rendering index, R,, could be observed when we increased the injection from 20 mA to 60 mA. These results indicate that such "n-UV+blue/green/red" white LED lamps are much more optically stable than the conventional "blue+yellow" LED lamps.