Diffractive optical element including a diffractive grating pattern
AssigneeAsahi Kogaku Kogyo Kabushiki Kaisha
InventorsTakashi Iizuka, Masato Noguchi, Tsutomu Sato
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Abstract
Disclosed is a diffractive optical element which includes a diffractive grating pattern ion a base plate. The diffractive grating pattern includes a plurality of phase gratings arranged in parallel lines extending along a predetermined direction to cause diffraction of an incident beam. Each of the plurality of phase gratings has an asymmetrical phase pattern. There is a phase gap, ΔP, representing a phase difference (in radians) between an end point and a beginning point of each phase pattern. The phase gap, ΔP, is substantially equal for each of the plurality of phase gratings and satisfies the relationship. 0.7π<|ΔP|<1.2π.
Claims4
A diffractive optical element, comprising a cylindrical surface provided with a diffractive grating pattern, said diffractive grating pattern including a plurality of phase gratings arranged in parallel lines extending along a circumference of said cylindrical surface to cause diffraction of an incident beam, wherein a beam incident on said diffractive grating pattern is divided and emitted into a plurality of diffracted beams;
- wherein a surface of said optical element from which said diffracted beams are emitted is cylindrical having a curvature that is substantially the same as a curvature of said cylindrical surface, and
- wherein said diffractive optical element has a meniscus shape and has substantially no total magnifying power.
Dependencies are inferred from the claim text.