Effect of the amount of phosphor silicone gel on optical property of white light-emitting diodes packaging

Effect of the amount of phosphor silicone gel on light extraction efficiency (LEE), correlated color temperature (CCT) and angular color uniformity (ACU) of white light-emitting diode (LED) packaging was investigated by Monte Carlo ray-tracing simulations. The optical model of GaN-based conventional LED chip was identified and the detailed simulation process was presented. It was discovered that the LEE for yellow light increased and the LEE for blue light decreased with the increase of the amount of the gel, but the total LEE had the same trend with the LEE for blue light. It was also discovered in the simulations that the CCT decreased with the increase of the amount of the gel and there existed yellow rings at the edges of the radiation pattern. It was concluded that the amount of the phosphor silicone gel played an important role in affecting the LEE, CCT and ACU, and it was a key factor in determining the consistency and reliability of the LEDs.