|
Prism-shaped, light-extraction elements that are removed from—or added to—solid light guides are often used in signal and interior automotive lighting systems. These elements can be optimized to provide spatially-uniform (or other desired spatial distribution) light whose angular centroid is aimed in appropriate directions to meet intensity specification test points [1], [2]. Recent work [3] has also examined the efficiency of these lamps and found that face curvature and prism surface width can significantly affect the shape of the intensity distribution, and therefore be used to increase the lamp efficiency, by matching the shape of the intensity test point distribution more closely. Changing the shape of the intensity distribution can also be used to build in more design tolerance. In this work, we first demonstrate how the efficiency of a Daytime Running Lamp (DRL) luminaire can be improved using a trial-and-error approach and the lessons learned in [3]. Next, we implement an optimization approach for the profile W parameter (to change the prism surface width locally) and spread parameter and demonstrate that the optimizer can find a slightly better solution than the trial-and-error approach using the same starting point (620 required lumens improved to 414 lumens). Finally, we use the optimization approach to design two other important design forms; first without and then with efficiency parameters included in the optimization. In both cases, we demonstrate improved efficiency designs: a symmetric circular DRL improved 394→325 required lumens, and a non-symmetric eyebrow DRL improved 365→245 required lumens.
|
