Patent ID: 8434905

Claim:
An LED based precision approach path indication (PAPI) system for guiding a landing aircraft to a pre-determined approach path comprising of multiple light housing assemblies (LHAs), each of the LHAs comprising of one or more lighting assembly modules, wherein each of the lighting assembly modules comprises: an array of white LEDs; an array of red LEDs positioned above said array of white LEDs; a plurality of collimating lens, each being placed in front of each LED of said array of white LEDs and said array of red LEDs; an optical combiner being placed in front of said array of red LEDs and being slightly above a first plane where said array of white LEDs are placed; and a projection lens set which is positioned in front of said optical combiner; wherein said optical combiner is a six face lens comprising an input refractive surface facing said LEDs, an output projection surface facing said projection lens set, a flat top surface, and a flat bottom surface having a reflective coating to block white light and increase white light intensity near transition zone, said output projection surface having a filter coating which is transparent with red light.