The invention discloses a small-F number multi-
wavelength standard spherical reference lens
assembly. The small-F number multi-
wavelength standard spherical reference lens
assembly adopts the working wavelengths of 632.8 nanometers, 543.5 nanometers and 532 nanometers; achromatism of the lens
assembly is achieved by using low-chromatic dispersion crown glass ZK7 and high-chromatic dispersion
flint glass ZF6; the small-F number multi-
wavelength standard spherical reference lens assembly adopts a three-piece lens design, and consists of a doublet positive lens, a negative lens, and a positive lens with a standard spherical surface as the last surface; the
caliber, the F number and the top
focal length design theoretical value of the reference lens assembly are 100mm, F / 3 and 254.7mm respectively; except for the last mirror surface of the reference lens assembly, the other mirror surfaces are plated with three-point antireflection films with the wavelengths of 632.8 nanometers, 543.5 nanometers and 532 nanometers; through combination of the doublet positive lens and the negative lens, an approximately afocal feature of an optical structure is achieved, the sensitivity of the change of a
coincidence error between a focal point and the curvature center of the last surface along with the change of a mirror spacing is reduced, and installation and adjustment of the small-F number standard spherical lens assembly are facilitated.