High Concentration Photovoltaics (HCPV) require an optical system with high efficiency, low cost and large tolerance. We describe the particularities of the HCPV applications, which constrain the optics design and the manufacturing techonologies. IntroductionMinimizing energy cost (€/kWh) is necessary for the success of concentrated photovoltaic energy (CPV). Key to minimizing this cost is an efficient and low cost optical design, goals best met with the fewest elements and the maximum tolerances, but always maintaining the high concentration (>500) that offsets the cost of expensive highefficiency multi-junction solar cells [1]. CPV optical systems have usually only two stages (Primary and Secondary Optical Elements, or POE and SOE, respectively). This is because as the number of stages grows, the system becomes more complex and less efficient and as the number of stages reduces the concentration and the tolerance decreases. The POE is the first element intercepting the incoming solar energy. It is thus an element having a relative large area. The SOE is a smaller element which is either reflective or refractive.Comparing to other optical components in other applications, CPV optics has two main singularities: (a) the cost targets constrain dramatically the fabrication technologies, and (b) the non-linear electrical performance of series connected solar cells affects the merit function for tolerancing.