Design method for large visual field optical system lens hood with scan mirror

The invention discloses a design method for a lens hood of an optical system with wide field of view, which is provided with a directing mirror and is used to design the preposed lens hood of a telescope objective optical system. The method is to obtain the shape of an inner cavity of the lens hood by a three-dimensional effective clear pipe composed by intercepting corresponding points on an edge contour line which is formed by the moving track of round beams of light of two reference surfaces which are connected by a straight line. In the invention, the method has the advantages of convenience, simpleness and quantification, and the designed lens hood has the minimum contour and dimension and does not shield light, thus largely restraining stray light from entering into imaging light paths directly.