Fabrication and optical properties of laser diodes based on composite phosphors film packaging

In this paper, we show that white light generation is possible using blue laser diode in combination with phosphor film. The phosphor film was prepared by mixing the green phosphor powder Y3Al5O12: Ce3+ and the red phosphor powder CaAlSiN3: Eu2+ with organic resin or silicone, and the phosphor film was pasted on the cap of laser diode, which encapsulates in conventional package for laser diode light-emitting device. The electroluminescence spectra, light distribution and correlated color temperature distribution of the laser diode light-emitting device were investigated. From the electroluminescence spectra, it can be found that the correlated color temperature of 5233 K can be reached, with color rendering index of 72.4. The luminous flux of the device is measured to be 56.37 lm with luminous efficacy of 223.71 lm/w. Through the analysis of near-field optics, it can be seen that although the lighting angle of laser diode light-emitting device is smaller than that of light-emitting diode light-emitting device, its correlated color temperature distribution and brightness distribution are better than that of light-emitting diode. So, it can be generalized that the laser diode light-emitting device has a great prospect in the field of lighting.