Diffractive optical element having a reflective member disposed between different grating wall surfaces thereof, and optical system and optical apparatus having the diffractive optical element

摘要

A diffractive optical element used as a lens of an optical system includes a first diffractive grating that includes a first grating surface and a first grating wall surface, a reflective member disposed on the first grating wall surface, and a second diffractive grating that includes a second grating surface and a second grating wall surface, and that is disposed so that the second grating surface contacts the first grating surface and the second grating wall surface contacts the reflective member. When off-screen light having an incident angle larger than that of off-axis light flux enters the diffractive optical element at a predetermined incident angle, an emission angle of light having the maximum intensity emitted from the first or second grating wall surface is appropriately set. The maximum width of the reflective member and a grating pitch of each of the first and second diffractive gratings are appropriately set.