ENDOSCOPE WIDE-ANGLE LENS Russian patent published in 2003 - IPC

FIELD: endoscopy, individual examination of human internal organs, hollow spaces of machines and mechanisms and so forth. SUBSTANCE: endoscope lens has four components. First component comes in the form of negative meniscus, fourth component has form of collecting lens. Aperture diaphragm is located between second and third components, by front focus of third and fourth components. Second positive component includes main lens and two lenses installed in front of it, first lens is negative lens with large curvature of second surface in ray path, second lens is meniscus facing image with convexity and third main lens is biconvex lens. Third component is negative lens made of material which refractive index changes with reference to basic index n₀ in direction r perpendicular to optical axis by law established by equation specified in formula of invention. Fourth component-collecting lens comes in the form of two positive lenses, second lens having last surface aligned with image surface. Focal powers of endoscope lens, of components and lenses included in them are tied up by relations given in formula of invention. EFFECT: diminished distortion with improved quality of image over entire field. 1 dwg