| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a zoom optical system which is capable of focusing and variable power, without an actuator. <P>SOLUTION: A zoom optical system OS1 includes a first group G1, a second group G2 and a third group G3 arranged in this order from a side of an image surface F. The first group and the third group G1 and G3 respectively include liquid crystal lenses. When a focal distance of the second group G2 is f<SB POS="POST">2</SB>, a distance between the image surface F and a main surface of the first group G1, a distance between the main surface of the first group G1 and a main surface of the second group G2 and a distance between the main surface of the second group G2 and a main surface of the third group G3 are respectively equivalent to f<SB POS="POST">2</SB>. The zoom optical system OS1 is controlled so that a sum of the focal distance for the first group G1 and the focal distance for the third group G3 is equivalent to f<SB POS="POST">2</SB>. <P>COPYRIGHT: (C)2013,JPO&INPIT |
