Mirror lens e.g. observation lens for use in e.g. spatial spectrometer in field monitoring, has four mirrors, where first and fourth mirrors are deformed to allow position of image plane of lens to remain unchanged in range of focus depth

摘要

The lens (100) has four mirrors (110-140), where the first and fourth mirrors (110, 140) are formed as deformable mirrors. The mirrors are arranged so that a bend optical path (102) extends from the first mirror (110) to the fourth mirror (140). The first and fourth mirrors (110, 140) are deformed so that an image angle of the lens is changed by deformation of a mirror surface of the first mirror (110) with deformation of a mirror surface of the fourth mirror (140) to allow a position of an image plane (160) of the lens to remain unchanged in a range of a focus depth. Independent claims are also included for the following: (1) a spatial spectrometer having a mirror lens (2) an image recording system having a mirror lens (3) a method of operating a central shadowing effect free mirror lens.