| 摘要 |
PURPOSE:To deform a surface shape of an elastic body as it remains roughly spherical, even if the rigidity ratio is not high, by constituting the titled element so that the elastic modulus of an elastic body of a driving member side becomes higher than the elastic modulus of an elastic body being adjacent to the opposite side to the driving member of said elastic body, and also, the elastic body of the driving member side decreases its thickness continuously as it goes to an optical axis. CONSTITUTION:An elastic body 10 shaped like a plano-concave lens is constituted by laminating two elastic body 10a and elastic body 10b in the direction of an optical axis (h), the elastic body 10a of a driving member 4 side is shaped so that its thickness decreases continuously as it goes to the optical axis (h) in the peripheral part of the optical axis, and also, the elastic modulus of the elastic body 10a is higher than the elastic modulus of its adjacent elastic body 10b. As for a range in which thickness of the elastic body 10a decreases continuously as it goes to the optical axis (h), only a range A in which a variable focus optical element is used effectively is enough, and it is unnecessary that thickness becomes thin continuously in the whole of the elastic body 10a. In such a way, by thickening the peripheral part of the elastic body 10a, and on the contrary, by thinning the center part, it becomes possible to bring the surface of the elastic body 10 close to a spherical shape.
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