Cylindrical Rod Phosphor Structure for Laser-Driven White Lighting

In this article, a cylindrical rod phosphor structure was developed and used for laser-driven white lighting. The blue light emitting from the laser diode (LD) with limited divergence enters the cylindrical rod containing phosphor and excites the yellow phosphor particles in the cylindrical rod to generate white light. Multiple phosphor blends with yellow and red phosphors were also applied to the cylindrical rod phosphor structure to enhance the red luminescence of white light with a low correlated color temperature (CCT). An advanced structure with a surrounding transparent layer around the central cylindrical rod containing phosphors was also investigated to enhance the possibility of the blue light absorption by phosphors in the cylindrical rod region away from the LD. The cylindrical rod phosphor structures with or without the surrounding transparent layer were fabricated to produce laser-driven white lighting, and the optical characteristics of the cylindrical rod phosphor structures with different phosphor concentrations or yellow-to-red phosphor weight ratios were examined.