Patent ID: 8072693
Filing Date: 2011-12-06
Classification: G02B,G03B

Abstract:
1. An optical system, which is adapted to form an image having a full 360° (panoramic)-direction angle of view on an image plane or project an image located on an image plane at a full 360°-direction angle of view, and comprises a front unit having at least two reflecting surfaces, each rotationally symmetric about a center axis, and a rear unit that is rotationally symmetric about the center axis and has positive power, characterized in that: said front unit includes, in order of travel of light rays in the case of an imaging system or in reverse order of travel of light rays in the case of a projection system, a first reflecting surface on which a light beam coming from afar is incident and which is located opposite to an entrance pupil in a section including a center axis with the center axis interposed between them, and a second reflecting surface located on the same side as the first reflecting surface with respect to the center axis, wherein a center of the first reflecting surface is located more on the rear unit side than a center of the second reflecting surface in a center axis direction, and the entrance pupil in the section including the center axis is located between an outer periphery of the first reflecting surface and an outer periphery of the second reflecting surface, the light beam coming from afar passes through said front unit and said rear unit in order, forming an image at a position of said image plane off the center axis, the entrance pupil is positioned off the center axis in the section including the center axis, and positioned on the center axis in a section that is orthogonal to the section including the center axis, and said rear unit is constructed of an optical system comprising at least two groups and having positive power.