Diode laser illuminated automotive brake lamp using a linear fanout diffractive optical element

Abstract

Marinelli and Remillard discussed the design and fabrication of diode laser illuminated automotive signal lamps.1 The optics are made from thin (~5 mm) plastic sheets that manipulate light using reflection and refraction from edges, surfaces, and shaped cut-outs. The resulting lamps can be well under 1 inch in thickness providing functional and styling advantages not attainable with conventional automotive lighting systems. Functionally, the sheet optic consists of a section that receives, divides, and expands the laser light (the manifold), and a section that directs it out of the lamp into the appropriate beam pattern (the kicker). The kicker is the visible part of the lamp optic, and the most efficient use of space is realized by maximizing the ratio of kicker to manifold area. Here we describe the design and fabrication of a thin, laser illuminated brake lamp that uses a diffractive optical element (DOE) at the entrance of the manifold. The DOE provides a compact way of uniformly spreading the light exiting the fiber, and allows for smaller manifolds than those discussed in the previous work.