Superachromatic UV and visible focusing objective lens

摘要

A superachromatic focusing objective lens which focuses wavelengths extending between the ultraviolet and the visible wavelength spectrum and is able to achieve superachromatic correction for three wavelengths within the visible spectrum is disclosed. The present objective lens includes an achromatic lens to assist in the correction spherical and coma aberration, a modified gauss for minimizing spherochromatism, a reversed modified gauss for adding symmetry to aid in the correction of coma, distortion and lateral color aberrations, and a stop located between the modified gauss and the reverse modified gauss. A glass plate is provided for forming a splatter shield to protect the lens from debris, and may be used to define one wall of a vacuum chamber. The elements of the objective lens may be made from various glasses to include calcium fluoride, quartz, and barium fluoride.