Аннотация:We demonstrate that the needle optimization technique enables the effective design of optical coatings for applications which require a specific spectral response over a wide angular range. A preliminary choice of the most useful layer materials is discussed in connection with the question of the design optimality. It is shown that in many cases two-material designs with the lowest and highest accessible refractive index values are optimal from a practical point of view. It is also shown that in some cases intermediate refractive index values are quite necessary to achieve a good approximation of design targets.