| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem that when a luminous flux from a photographing optical system is reflected at an acute angle by a reflecting mirror, the reflecting mirror is disposed at the back on the optical axis of the photographing optical system, a distance in the optical axis direction of the photographing optical system becomes longer, and a size reduction is hindered. SOLUTION: The movable reflection mirror 18 is disposed so that, in its reflecting position, the luminous flux of a subject from a photographing optical system 14 is reflected at obtuse angle with respect to the optical axis O1 of the photographing optical axis (α>90°). A focusing plate 40 is disposed above the reflecting mirror 18 such that one side 40a at the subject side of the focusing plate 40 is more separated from the optical axis O1 of the photographing optical system than one edge 40b at the opposite side of the plate 40. Thereby, the luminous flux reflected by the reflection mirror is imaged on the focusing plate. A pentamirror 42 includes a pair of roof faces (first and second reflecting faces) 42a and 42b and a third reflecting face 42c. The image formed on the focusing plate 40 is reflected by the pair of roof faces and inverted right to left, further reflected by the third reflecting face, then made incident on an eyepiece optical system 44, and observed as an erect image. COPYRIGHT: (C)2008,JPO&INPIT
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