Cone lenses are rod lenses with a conicial point, and are used by shining incident light along the long axis of the lens to create a circular illumination pattern. The diameter of these lenses are often ground to reduce stray light.

Rod lenses are a varient of cylindrical lenses used to focus incident light into a line. The outside faces of the lens are typically ground and the outside diameter polished. These lenses are often used for generating line images from circular laser beams.

Structure of Part of Endoscope