Light emitting diode based PAPI design incorporating linear diode arrays, cylindrical optics, and linear light combining mirror

Abstract

This invention presents a method for overcoming limitation in brightness and heating effects for LED based Precision Approach Path Indicators and allowing both colors to be imaged in the far field with the proper abrupt transition between the red and white sectors. This method relies on the use of linear arrays of LED's and cylindrical optics.

What is claimed is: 
     
         1 . A Precision Approach Path Indicator system, comprising:
 (a) a plurality of LED's arranged in substantially linear arrays   (b) a means for control of the brightness of the light,   (c) one array that produces a red sector and another array that produces a white sector, and   (d) whose light is incident on a beam combining or sector delineating optic, the edge of which is reimaged by a cylindrical lens, or cylindrical lens array to project the red and white sectors.   
     
     
         2 . Precision Approach Path Indicator system of  claim 1 , comprising:
 (a) where said sector delineating optic is a beam combining mirror where the mirror has a precision linear edge which is located at the back focal point of the cylindrical lens, and aligned with the axis of the cylindrical lens.   
     
     
         3 . A Precision Approach Path Indicator system, comprising:
 (a) a plurality of LED's arranged in substantially linear arrays,   (b) a means for control of the brightness of the light,   (c) one array that produces a red sector,   (d) whose light is incident on a sector delineating mask which is located at the back focal point of a cylindrical lens, aligned with the axis of the cylindrical lens, and the edge of which is reimaged by the cylindrical lens, or cylindrical lens array, to project the red sector,   (e) one array that produces a white sector,   (f) whose light is incident on a second sector delineating mask which is located at the back focal point of a second cylindrical lens, aligned with the axis of the cylindrical lens, and the edge of which is reimaged by the cylindrical lens, or cylindrical lens array to project the white sector.