YAG: Ce3+ phosphor/silicone composites are widely used in solid-state lighting as a light converter to achieve white lighting. However, because of high thermal resistance and low thermal stability, the luminous performance of YAG: Ce3+ phosphor/silicone composite deteriorates rapidly when excited by high-power-density blue-laser. To explore the potential of blue laser-excited YAG: Ce3+ phosphor/silicone composites, the luminous performances under different blue laser power conditions were characterized by both the reflective and transmissive excitations using a self-built three-integrating-sphere system. Furthermore, the Monte-Carlo Ray-tracing simulation was used to illustrate the light-transmission and energy conversion mechanism in the phosphor/silicone composites. The results showed that: (1) The YAG: Ce3+ phosphor/silicone composite could be excited by the 0.292W laser light with the peak wavelength of 445nm, excessive laser power will cause phosphor thermal quenching and silicone carbonization. (2) The luminous flux of the composite under both the reflective and transmissive excitations gradually increased with the increase of phosphor concentration; correspondingly, the color coordinate moved to the yellow region, and the Correlated Color Temperature (CCT) gradually decreased. (3) The simulation results indicated that under the same phosphor concentration, the luminous flux obtained by reflection excitation was largely higher than that by the transmission excitation, as the light re-conversion and strong back-scattering were occurred in the reflective and transmissive laser excitation respectively.

With higher efficiency, brightness and reliability than traditional light sources, LED has been widely applied in automotive headlamps. The smaller volume and higher power density of a LED package drive the design of automotive headlamps with LED matrix model, such as adaptive driving beam (ADB) system. This paper proposed a matrix automotive headlamp module with rectangle lens array to balance the contradiction between improving the visual condition of driver in the nighttime driving and reducing the impact of glare on others from the opposite direction. Firstly, according to the requirements on light distribution provided by the GB 25991 regulation, the optimized optical design, including configuration of LEDs and structure of optical system, was developed based on the optical simulations. Secondly, the thermal management of the module was conducted by using the fluid finite element simulation through considering both the natural and forced convections. The results show that: 1) a LED matrix with specially designed rectangle lens array that contains different size of lenses can produce the independent and nonoverlapping rectangular light spots as required; 2) the heatsink with optimal designed pin fins can provide more effective thermal dissipation in convection.