APPAREIL A OBJECTIF A FOCALE VARIABLE AVEC REGLAGE DE MISE AU POINT ET DISPOSITIF D'IMAGERIE OPTIQUE ASSOCIE

摘要

A zoom lens with focus adjusting comprises independently controlled zooming structure 20 and focusing structure 60. The structure 20 is driven by USM comprising a first tube 22, a second tube 23, a first set of piezoelectric elements 21 and a third tube 24. The structure 60 is driven by voice coil motor (VCM). Threads 221 are formed on the inner surface of the first tube. The second tube has threads 231 on the outer surface and threads 232 on the inner surface and is placed in the first tube 22. The thread pitch and/or the spiral direction of the threads on the outer surface is different from that of the threads on the inner surface. The third tube 24 with threads 241 formed on the outer surface thereof is placed in the second tube and fixed radially with respect to the first tube to give simple rectilinear motion to the third tube and maintains the stability of the optical axis. The combination of different driving methods makes better use of lens sets of different functions.