CATADIOPTRIC PHOTOGRAPHIC LENS

摘要

A catadioptric photographic lens include; a first reflecting mirror, a second reflecting mirror, and a lens group, arranged in order from an object so that light reflected by the first reflecting mirror is reflected by the second reflecting mirror before passing through the lens group and forms an image of the object upon a predetermined image plane wherein; the first and the second reflecting mirror are off-center on the reference plane; reflection surfaces of the first and the second reflecting mirror are rotationally asymmetric aspheric surfaces; the reflection surface of the first reflecting mirror is concave toward the object on the reference plane and on the first orthogonal plane; and the surface closest toward the second reflecting mirror in the lens group having two lenses made from the same optical material as one another is a rotationally asymmetric aspheric surface.

主权项

1. A catadioptric photographic lens comprising,
a first reflecting mirror, a second reflecting mirror, and a lens group, which arc arranged in order from an object so that light reflected by the first reflecting mirror is reflected by the second reflecting mirror before passing through the lens group and forms an image of the object upon a predetermined image plane, wherein, when a straight line that is extended between a center of the object and a center of the first reflecting mirror is defined as a first reference axis; a straight line that is extended between a center of the second reflecting mirror and a center of the image plane is defined as a second reference axis; a plane including the first reference axis and the second reference axis is defined as a reference plane; a plane passing through the center of the first reflecting mirror, perpendicular to the reference plane, and subtending a predetermined angle with respect to the first reference axis is defined as a first orthogonal plane; a plane passing through the center of the second reflecting mirror, perpendicular to the reference plane, and subtending a predetermined angle with respect to the second reference axis is defined as a second orthogonal plane; and a plane passing through a center of a surface of the lens group that is closest toward the second reflecting mirror, perpendicular to the reference plane, and parallel to the second reference axis is defined as a third orthogonal plane: the first reflecting mirror and the second reflecting mirror are off-center on the reference plane; a reflection surface of the first reflecting mirror is a rotationally asymmetric aspheric surface, and has a shape that is concave toward the object on the reference plane and on the first orthogonal plane; a reflection surface of the second reflecting mirror is a rotationally asymmetric aspheric surface; the surface in the lens group closest toward the second reflecting mirror is a rotationally asymmetric aspheric surface; and the lens group has two lenses that are made from the same optical material as one another.