| 摘要 |
PROBLEM TO BE SOLVED: To provide an imaging optical system which suppresses the deterioration of image quality caused by ghost while attaining compact size, by optimizing the shape of a prism disposed at a position near an image face. SOLUTION: An imaging optical system 10 includes an incident-side prism 11 and the image-face-side prism 12, both of which reflect incident light by bending it almost 90°. A light shielding plate 3 is disposed on the incident face 12a of the image-face-side prism 12. In addition, the shape of the image-face side prism 12 is formed so as to satisfy relational expression: 0.53<a/c<2.0, wherein (a) denotes a distance from the point at which the optical axis AX of the imaging optical system 10 and the reflecting face 12c of the image-face-side prism 12 intersect and to the emission face 12b of the prism 12 and (c) denotes the maximum width of an image within the optical-path bending face of the imaging optical system. This suppresses the occurrence of ghost or the like caused by incidence of light beam outside a field angle onto the image face. COPYRIGHT: (C)2007,JPO&INPIT
|
