Spherical, aspherical Fresnel lenses and pillow lenses have an extensive use in rear lamp design. These systems, using refraction or TIR (Total Internal Reflection), allow to control the geometrical spread and the photometry of the luminous flux.
A transparent system guarantees a homogeneous and uniform light distribution, attractive appearance, lower costs and reduced overall dimensions.
Nevertheless a simple lens system hasn't enough efficiency in collecting luminous flux. Generally the solid angle subtended by lens is small and to improve the optical efficiency, designers use reflectors.
TIR reflectors are transparent segmented surfaces, which match the traditional lens performances with high efficiency and new style.
This paper discusses the principles, features and performances of TIR reflectors. It also presents the new software developed to design these systems, showing the achieved results.