Light-directing system based on reflecting surfaces. The main characteristics of a reflector are its reflectance and spread. For concave and convex mirror reflectors, a further characteristic is the curvature of its cross section, i.e. the reflector contour. Parabolic reflectors align the light from a light source located at the focal point into a parallel beam, spherical reflectors reflect it back to the focal point and elliptical reflectors focus it to a second focal point.