| 摘要 |
PROBLEM TO BE SOLVED: To provide a finder optical system for a camera which is mounted on a single-lens reflex camera and suppresses the increase in the length while reducing the height. SOLUTION: The finder optical system is provided with: a 1st wedge type prism 13 where a 1st angleθ1 is formed by an incident surface 13a on which an imaged luminous flux is made incident from a focusing screen 12 and an exit surface 13b; and a 2nd prism 14 whose optical surface 14a functioning as an incident surface is arranged in nearly parallel to the exit surface 13b with leaving a gap. In the 2nd prism 14, the optical surface 14a is nearly parallel to the 1st angleθ1 of the 1st prism 13, and provided that the total reflection angle of the material of the 2nd prism 14 is expressed byθr2, the luminous flux made incident on the optical surface 14a from the 1st reflection surface has a 2nd incident angleθ2 larger than the total reflection angleθr2. COPYRIGHT: (C)2006,JPO&NCIPI
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