Design and characterization of an optical light source based on mixture of white and near-ultraviolet light emitting diode spectra

An optical light source based on a solid-state lighting technology is designed. Main components of the light source are a phosphor-converted white and a near-ultraviolet (near-UV) light emitting diodes (LEDs), the spectral power distributions (SPDs) of which are mixed using a fiber optic combiner. The near-UV LED is used for improving insufficient SPDs of the white LED at shorter wavelengths of the visible radiation. Stable direct current power supplies are also designed and used to operate each of the LED separately. Three steps of the driving current can be selected by means of serial resistors altered with a commutator at nominal current values of similar to 40%, similar to 50%, and similar to 69%. The light source can be used for many characteristic measurements within the scope of photometry and colorimetry. (C) 2011 American Institute of Physics. [doi:10.1063/1.3584870]