US Patent 7154683 Five-element optical device

An optical device with five air-spaced optical elements. An optical device in the form of an eyepiece is disclosed with a center negative lens and two outer positive lenses on each side of the intermediate negative lens. The eyepiece transmits light from an object to an exit pupil along angles corresponding to the position of a focus point on an object. In a preferred embodiment the positive lenses are identical.