Fast lens with the recommendations of the entrance pupil

摘要

FIELD: photography; projection equipment.;SUBSTANCE: lens has four components and aperture diaphragm installed in front of the lens. First component is made in for of positive meniscus turned with its concavity to object. The second component is negative lens, the third component consists of two single positive lenses and the fourth component has to be meniscus turned with its concavity to object and glued of positive and negative lenses with focal powers of (1,1…1,3)ϕ_l and (-1,5…-1,6)ϕ_l correspondingly. Focal power of meniscus doesn't exceed 0,01ϕ_l, thickness of meniscus is equal or thicker than 0,5f'_l, where ϕ_l and f′_l - focal power and focal length of length correspondingly. All the lenses can be made of materials having high gamma-ray radiation resistance up to power of 5x10⁶ R/h roentgen/h. Radiation resistant aperture lens with relative aperture up to 1:1,5 is provided, which objective has angular field being equal or wider than 35 deg and back focal segment s_f being equal to 0,5f'_l to mount aperture diaphragm in front of lens to adjust illumination.;EFFECT: improved efficiency of operation.;2 cl, 3 dwg