Efficiency and stability of a phosphor-conversion white light source using a blue laser diode

A white light source using direct phosphor-conversion excited by a blue laser diode is presented. In this preliminary study we have investigated the influence of phosphor’s thickness and operating current of the laser diode over the (x, y) chromaticity coordinates, Correlated Color Temperature (CCT) and Color Rendering Index (CRI). The best values found were 4000 K and 94. A 40 lm/W luminous efficacy was achieved together with a CRI close to 90 for an operating current of 0.8 A. Those values, to the best of our knowledge, were not previously reported in the literature.