Patent ID: 7573652

Claim:
A focusing device comprising: a lens mount comprising a hollow sleeve, the hollow sleeve comprising a wall, a bushing integrally formed on an inside of the wall of the sleeve, an annular step protruding radially and inwardly from an inner surface of the bushing, a portion of the bushing below the annular step forming a collar part, a first internal thread defined in the annular step; and a cutout defined through the wall; a driving mechanism comprising a motor and a driving gear; a hollow first barrel comprising a wall, a top portion of the first barrel forming an annular part, a collar step formed on an outside of the wall of the first barrel below the annular part, the collar step abutting against the collar part, and the annular part defining a first outer thread and an annular gear on the outside of the wall of the first barrel below the collar step; and a first lens element received in the first barrel; wherein the first barrel is movably secured in the lens mount by means of the first outer thread engaging with the first internal thread, the driving mechanism protrudes through the cutout of the lens mount and is engaged with the annular gear, and the motor drives the driving gear to drive the annular gear to rotate in the lens mount so that the first barrel ascends or descends relative to the lens mount.