DIFFRACTIVE OPTICAL ELEMENT AND IMAGING APPARATUS USING THE SAME
It is an objective of the present disclosure to prevent or reduce cracks in edge portions of raised portions of a diffractive optical element. A diffractive optical element includes a diffractive surface. The diffractive surface includes a plurality of raised portions. Each of the raised portion has a first surface having a diffraction function, and a second surface extending upright to be connected to the first surface. A tilt angle of the second surface relative to an optical axis varies according to a region in the diffractive surface.
1 . A diffractive optical element, comprising:
a diffractive surface,
wherein the diffractive surface includes a plurality of raised portions,
each of the raised portion has a first surface having a diffraction function, and a second surface extending upright to be connected to the first surface,
a tilt angle of the second surface relative to an optical axis varies according to a region in the diffractive surface, and
the tilt angle of the second surface is larger in a region where a height of the raised portion is higher than in a region where the height of the raised portion is lower.
2 . The diffractive optical element of claim 1 , wherein
the tilt angle of the second surface is different between a central region and an outer region of the diffractive surface.
3 . The diffractive optical element of claim 2 , wherein
the tilt angle of the second surface is larger in the outer region than in the central region of the diffractive surface.
4 . (canceled)
5 . An imaging apparatus, comprising:
the diffractive optical element of claim 1 .