| 摘要 |
An imaging element includes a diffraction optical element on which an off-axis beam with a field angle is incident and a stop. Of beams having different field angles and incident on the diffraction optical element, beams having incident angles larger than the incident angle of a principal light ray of the beams incident on the grating surface of the diffraction optical element are partially shielded by a light-shielding member, so that the diffraction efficiencies of orders adjacent to a design order are kept low and hence imaging performance almost free from flare can be achieved even if a beam with a field angle is incident.
|
