Nowadays,　light　emitting　diodes　(LEDs)　are　becoming　a　natural　source　choice　for　display　illumination　due　to　their　small　size,　lower　power　consumption　as　well　as　lower　heat　generation.　To　be　useful　in　practical　display　applications　and　to　further　improve　the　performance　of　LED-based　illumination　system,　a　secondary　optical　design　for　LED　illumination　is　required　to　rearrange　the　direct　output　of　LEDs　so　as　to　achieve　a　desired　illumination.　In　this　paper,　a　numerical　modeling　based　on　the　direct　datasheet　fit　is　used　to　optimize　and　analyze　the　uniform　illumination　system　designs,　and　close　attention　is　paid　to　the　LED　source　model.　The　uniformity　of　typical　square　and　circular　array　distributions　are　analyzed　for　a　commercial　non-perfect　Lambertian　LED　model.