LONG FOCAL-LENGTH TELEPHOTO LENS Russian patent published in 1994 - IPC

FIELD: spectrometry. SUBSTANCE: long focal-length telephoto lens is designed for operation as part of spectrozonal chamber. Lens includes six lenses and consists of four components. First component is convex-flat positive lens, second component has shape of meniscus facing image with concave side and is composed of two cemented together first positive and second negative lenses. Shape of these lenses changes depending on working spectral range: these are meniscuses facing image with concavity in blue region of spectrum, these are biconvex and biconcave or convex-flat and flat-concave lenses in three other regions. Third component is negative flat-concave lens. Fourth component is positive thick convex-flat lens in front of which thin weak negative meniscus turned with convexity to image is placed. Aperture diaphragm is placed behind third component. EFFECT: improved operational characteristics. 4 cl, 2 dwg