| 摘要 |
PROBLEM TO BE SOLVED: To provide a compact imaging optical system of high optical performance while suppressing the increase of the cost, which can be loaded to a portable telephone and a portable information terminal. SOLUTION: The imaging optical system is constituted by having a 1st reflection prism 1 having positive optical power as a whole, an optical diaphragm, a 1st lens 2 having positive optical power, a 2nd lens 3 having negative optical power and a 2nd reflection prism 4 having positive optical power as a whole on an optical axis in order from an object side. Regarding the 1st reflection prism 1, the incident surface has negative optical power, the exit surface has positive optical power, and a planar reflection surface RL1 is arranged on the optical path between the incident surface and the exit surface. Regarding the 2nd reflection prism 4, the incident surface has positive optical power, the exit surface has negative optical power and a planar reflection surface RL2 is arranged on the optical path between the incident surface and the exit surface. The reflection surfaces RL1 and RL2 bend the incident light at about 90 degrees and reflect the light toward the 1st lens 2 or a plane-parallel plate 5. COPYRIGHT: (C)2006,JPO&NCIPI |
