A lens barrel includes a lens group that conducts light from a subject, a lens shell that holds the lens group; a string-formed shape memory alloy element that moves the lens shell in a direction of an optical axis, and a pair of guide shafts formed approximately in parallel to the optical axis of the...http://www.google.com/patents/US7295389?utm_source=gb-gplus-sharePatent US7295389 - Lens barrel, image-pickup unit having the lens barrel, and manufacturing method of the same
