The finite-difference time-domain method was employed to calculate light extraction efficiency of thin-film flip-chip In Ga N/Ga N quantum well light-emitting diodes(LEDs) with TiO_2 microsphere arrays. The extraction efficiency for LEDs with microsphere arrays was investigated by focusing on the effect of the packing density,packing configuration, and diameter-to-period ratio. The comparison studies revealed the importance of having a hexagonal and close-packed monolayer microsphere array configuration for achieving optimum extraction efficiency, which translated into a 3.6-fold enhancement in light extraction compared to that for a planar LED. This improvement is attributed to the reduced Fresnel reflection and enlarged light escape cone. The engineering of the far-field radiation patterns was also demonstrated by tuning the packing density and packing configuration of the microsphere arrays. The finite-difference time-domain method was employed to calculate light extraction efficiency of thin-film flip-chip In Ga N / Ga N quantum well light-emitting diodes (LEDs) with TiO 2 microsphere arrays. The extraction efficiency for LEDs with microsphere arrays was investigated by focusing on the effect of the packing density, packing configuration, and diameter-to-period ratio. The comparison studies revealed the importance of having a hexagonal and close-packed monolayer microsphere array configuration for optimizing optimum extraction efficiency, which translated into This improvement is attributed to the reduced Fresnel reflection and enlarged light escape cone. The engineering of the far-field radiation patterns was also demonstrated by tuning the packing density and packing configuration of the microsphere arrays.