| 摘要 |
PROBLEM TO BE SOLVED: To provide a compact and inexpensive optical system capable of imaging an angle of view having a wide observation on an imaging device with simple constitution, and to provide an endoscope using the same. SOLUTION: At least one of a first reflection surface 22 and a second reflection surface 23 is constituted of an extended rotational free curved surface formed by rotating a line segment in an optional shape having no symmetric surface around a center axis 2. Luminous flux incident on a transparent medium L constitutes such a first optical path A in a substantially Z-shape, wherein the optical path A passes through an aperture S, enters the transparent medium L through a first transmission surface 21, is reflected to an opposite side to an image surface 5 by the first reflection surface 22, is reflected to the image surface 5 side by the second reflection surface 23 and goes out to the image surface 5 side from the transparent medium L through a second transmission surface 24 in tracking order of a forward light beam. A portion between the first reflection surface 22 and the second reflection surface 23 of the first optical path A is constituted of only one side relative to a center axis 2. Accordingly, an intermediate image is not formed in the first optical path A but formed annularly on the image surface 5. COPYRIGHT: (C)2009,JPO&INPIT
|
