Optical element

DETAILED DESCRIPTION The present invention has been made in consideration of the aforementioned problems, and has as its object to suppress relative decentering of reflection surfaces, which must have highest precision, and to prevent optical performance from deteriorating, in an optical element in which a plurality of reflection surfaces with curvatures are placed and formed adjacent to each other.
It is another object of the present invention to increase the degree of freedom in aberration correction of an optical element, and to improve the imaging performance of the optical element.
It is still another object of the present invention to accurately set the spacing between reflection surface blocks at predetermined positions while facilitating the manufacture of the respective reflection surface blocks.
It is still another object of the present invention to prevent effective light rays in an optical element from being eclipsed.
It is still another object of the present invention to reduce the number of parts, to reduce errors produced upon movement of an optical element, and to prevent effective light rays in an optical element from being eclipsed.
It is still another object of the present invention to obtain a low-cost optical element, which can be formed by molding irrespective of its shape to have reflection surfaces at accurate positions.
It is still another object of the present invention to obtain an optical element which suffers less ghost.
It is still another object of the present invention to allow the directions of light rays that enter and leave an optical element to be set arbitrarily.
In order to solve the above-mentioned problems and to solve the objects, the first aspect of an optical element according to the present invention is characterized by the following arrangement.
That is, there is provided an optical element comprising a first reflection surface block formed by placing a plurality of reflection surfaces having curvatures at neighboring positions, and a second reflection surface block which opposes the first reflection surface block, and is formed by placing one or a plurality of reflection surfaces at neighboring positions, wherein the first and second reflection surface blocks are formed by a metal mold