Patent ID: 8767300
Filing Date: 2014-07-01
Classification: B23C,G01J,G02B,Y10T

Abstract:
1. A diffraction element comprising: a substrate with a curved surface having an anamorphic shape defined as a locus obtained by pivoting an arc (I) having a center (O) about a rotation axis that is a straight line (II); and a diffraction grating having gratings on the curved surface of the substrate, wherein the center (O), the arc (I), and the straight line (II) line exist in a same plane, wherein each of the gratings exists in a cross section orthogonal to the straight line (II), wherein both the center (0) and the straight line (II) are located on one side of the arc (I) in a direction perpendicular to the straight line (II) in the same plane, and wherein the curved surface has a curvature radius R in the same plane that is larger than a curvature radius r in the cross section orthogonal to the straight line (II).