An optical bending lens is composed of two different materials with a relief structure between them, pref. in a saw tooth shape. The refraction index of the first material is greater than that of the second, whilst the dispersion factor is lower. The condition below applies between 400 ( lambda 1) and 700 ( lambda 2) nm: n1( lambda 2)-n2( lambda 2)/n1( lambda 1)-n2( lambda 1) > n1( lambda 2)-1/n1( lambda 1)-1
