RESUMO
We present a novel lens model, to the best of our knowledge, that redistributes the light flux from an LED and generates the required shape of illumination. A cylindrical lens is widely applied as a condensing optical element in non-imaging optical systems. In this work, a light guide is introduced into the design of a cylindrical lens. Different from the universal cylindrical lens, this one is divided into a light guide surface and a cylindrical surface. The light guide surface leads rays from an LED to a cylindrical surface, making it possible to decrease substantially the width of the lens in comparison with a universal cylindrical lens. That is, the lens model acts as a light guide to lead light rays in the transversal direction and acts as a cylindrical lens in the longitudinal direction. This lens is much easier and more economical to design and manufacture in comparison with conventional cylindrical surface lenses or freeform surface lenses used to produce elongated irradiance distribution. The simulation run by the optical software LightTools shows that the lens designed in the new method, to the best of our knowledge, has a much smaller size than the conventional cylindrical lens, and the uniformity of illumination and efficiency of energy are also quite good. Results show that the efficiency of an elongated lighting area reaches 83.3%.