| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a small sized variable power finder having high variable power while securing a large angle of view at low magnification. <P>SOLUTION: The real image type variable power finder has: a first lens group G1 with negative refractive power; a second lens group G2 with positive refractive power; and a third lens group G3 with negative refractive power in this order from the object side, in additional has: an objective lens group OL having positive refractive power as a whole; a visual field frame F arranged in the vicinity of a focal surface of the objective lens group OL; first and second prisms P1, P2 making an object image formed by the objective lens group OL into an erect image; and an eye piece lens group EL having positive refractive power for observing the erect image and the visual field frame F. The objective lens group OL includes negative lens components (corresponding to G1 in Fig. 1) composed by material satisfying the following conditional expression nneg>1.55,νneg<30.00, where nneg is the refractive index of the material composing the negative lens component at the d line, andνneg is the Abbe number of the material composing the negative lens component. <P>COPYRIGHT: (C)2012,JPO&INPIT</p> |
