LENS SYSTEM FOR SCANNING DEVICE

摘要

A lens system includes a lens (18) and a non-periodic phase structure (16). A temperature-dependence of the spherical aberration of the lens is compensated by a temperature dependence of the spherical aberration of the non-periodic phase structure. A wavelength-dependence of the defocus of the lens is compensated by a wavelength-dependence of the defocus of the non-periodic phase structure. A wavelength-dependence of the spherical aberration of the non-periodic phase structure is compensated by a wavelength-dependence of the spherical aberration of the lens.