 
 <prompt> Wetin dey cause smaller loss, Stoke shift loss or internal optical losses? Based on di previous question, write a context wey contain di answer. E fit be 1 - 20 sentences. Context: <response>: Among di wahala wey dey face to improve di efficiency of LED-based white light sources na di development of more efficient phosphors. As of 2010, di most efficient yellow phosphor still be di YAG phosphor, with less than 10% Stoke shift loss. Losses wey dey come from internal optical losses due to re-absorption for di LED chip and for di LED packaging itself dey typically account for another 10% to 30% of efficiency loss. Currently, for di area of phosphor LED development, plenti effort dey spent on optimizing these devices to higher light output and higher operation temperatures. For example, di efficiency fit increase by adapting better package design or by using a more suitable type of phosphor. Conformal coating process dey frequently used to address di issue of varying phosphor thickness. 