270 degree half intensity angle LED retrofit light bulb based on planar light source coupling with reflective structure

In this study, an efficient LED retrofit bulb achieved half intensity angle of higher than 270 degree is demonstrated. The new design retained the low cost manufacturability and simultaneously overcome the challenging optical requirement. The experimental results indicated that the half intensity angles of the samples were larger than 270 degree and the efficacy is over 75lm/W, which is requested by US energy star.