Design of optical elements with two refractive surfaces to generate a prescribed intensity distribution

A novel technique for designing optical elements with two refractive surfaces intended to generate a required intensity distribution has been presented. The design procedure makes it possible to control the balance of deflection angles between the inner and outer surfaces. As an example, an optical element producing the intensity distribution for illumination of class A road has been designed. The optical efficiency of the computed element is 89 percent and such a secondary optics meets the requirements of class A road regulations when lamp poles are separated by a distance of 20-35 m.