Study of the total light flux measurement of wafer-level LED in a multichannel LED measuring system with non-imaging concentrator array

To raise the speed of characterizing wafer-level LEDs, simultaneous measurement for both electrical and optical properties in parallel is a necessity. A non-imaging concentrator array is designed to concentrate as much light as possible from LEDs for optical characterization of multiple points on the wafer. For the sake of meeting the requirements between the numerical aperture of the sensing fiber and the emitting half-cone angle from a Lambertian source, a reversed angle transformer (RAT) is used in this study. The simulation is conducted using the commercial software LightTools® , based on the Monte-Carlo ray-tracing method. According to the simulation, the entrance port can collect approximately 94% of radiance from a Lambertian source, and the concentration ratio of RAT is approximately 99%. Finally a design prototype is demonstrated in this paper to validate our design.