| 摘要 |
PROBLEM TO BE SOLVED: To make a focal length variable lens small-sized and to improve reliability of the lens. SOLUTION: The focal length variable lens is provided with: a cylindrical giantmagnetostrictive element 11 of which the hollow part serves as an optical path; an elastic sealing member 14 arranged on the optical path; a fluid 15 filled in the hollow part of the giantmagnetostrictive element 11 with the sealing member 14; and a coil 12. The giantmagnetostrictive element 11 is dislocated in a radial direction when the electric current flowing in the coil 12 is varied, and the pressure applied to the fluid 15 varies and the first and the second parts 14a and 14b of the sealing member 14 are deformed. In this way, in the focal length variable lens of the present invention, the focal length is varied according to the change in the electromagnetic field given to the giantmagnetostrictive element 11, and the movement of the fluid does not follow. Consequently, the entire focal length variable lens is made small and fluid leakage or the like is hardly caused. COPYRIGHT: (C)2006,JPO&NCIPI
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