| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a curvature variable power optical system which is hard to be affected by temperature variation, thin, small, and has high optical performance. <P>SOLUTION: A curvature variable power optical system is constituted by arranging: a first lens group 1 having positive refractive power; a second lens group having negative refractive power; a third lens group 3 having the positive refractive power; and a fourth lens group 4 having the positive refractive power in order from the object side. The first lens group 1 is constituted by arranging: a negative meniscus lens L<SB POS="POST">1</SB>whose convex surface is turned to the object side; a prism P<SB POS="POST">1</SB>for bending an optical path; a planoconvex lens L<SB POS="POST">2</SB>; and a biconvex lens L<SB POS="POST">3</SB>in order from the object side. In addition, the third lens group 3 is constituted by including an aperture diaphragm ST. A meniscus lens L<SB POS="POST">10</SB>whose concave surface is turned to the side of an image surface IMG is further arranged closest to the side of the image surface IMG in the fourth lens group 4. <P>COPYRIGHT: (C)2012,JPO&INPIT |
