Image pickup apparatus comprising an image pickup optical system including an optical element having optical incident and optical emergent surfaces and a fine textured structure having a mean pitch shorter than a wavelength of visible light, and an image pickup unit configured to receive an image formed by the image pickup optical system, and meeting a specified diameter condition

摘要

An image pickup apparatus includes an image pickup optical system and an image pickup unit configured to receive an image formed by the image pickup optical system. The image pickup optical system includes an optical element having optical incident and optical emergent surfaces disposed between an aperture stop and an object and a fine textured structure having a mean pitch shorter than a wavelength of visible light and formed on at least one of the optical incident and optical emergent surfaces. The conditions 3.5RA/R0 and 60°2ω are satisfied, where RA is an effective diameter of the optical surface having the fine textured structure, R0 is a diameter determined by a height when light rays forming an image on an optical axis pass through the optical surface having the fine textured structure, and 2ω is an angle of view in image taking limited by a size of the image pickup unit.