HIGH APERTURE-RATIO MAGNIFIER Russian patent published in 1997 - IPC

FIELD: wide-application optical instruments with high requirements to aperture ratio and picture quality, in particular, optoelectronics for examination of picture produced on the cathode-ray tube screen. SUBSTANCE: the magnifier has four components, of which the first, second and fourth components are single collecting lenses made of glass of the same grade with 1,6<n_e<1,75 and 50<υ_e<60, and the third component is a diverging meniscus with its convexity facing the object, it is made of glass with 1,65<n_e<1;8 and 25<ν_e<40. The focal lengths of the components are bound up by relations: , where f-focal length of the magnifier, and f₁,f₂,f₃,f₄-focal lengths of the respective components. EFFECT: enhanced quality of picture. 2 cl, 2 dwg