Co-sintered ceramic converter for transmissive laser-activated remote phosphor conversion

By confining a low-scattering ceramic phosphor conversion region within a high-scattering alumina substrate, we fabricated high-luminance laser-activated remote phosphor (LARP) with excellent thermal dissipation for white light generation. A dichroic mirror coating on the pump side recycles both luminescence and re-scattered pump light to improve efficacy. As a result, we demonstrated a transmissive LARP converter that achieves 600 lumens with 4.3 W of the blue pump power at an ambient temperature of 25 & DEG;C. Due to the strong cavity effect of the highly scattering substrate, a corresponding peak luminance of greater than 700 Cd/mm(2) was observed. At 80 & DEG;C ambient, the converter can still achieve greater than 500 lumens and peak luminance exceeding 500 Cd/mm(2). Simulations based on the optical diffusion approximation are generally in good agreement with data, although they overpredict luminous flux, suggesting the dichroic coating was not optimal and further performance improvements may be achievable.