Patent ID: 7400068
Filing Date: 2008-07-15
Classification: G02B,G03B,G11B,H02K,H04N

Abstract:
1. A voice coil motor apparatus, comprising: a movable magnetic part, utilized to form a primary magnetic field for generating a thrust and a leakage magnetic field for a pre-load, wherein said movable magnetic part comprises: a static electrical part, comprising at least one coil that an appropriate current is to flow through; a lens holder, rigidly coupled to said movable magnetic part to form a moving member, wherein said lens holder has plurality of round holes or open arc faces to form a plurality of guiding faces; a plurality of guidance steel shafts, made of a ferromagnetic material and used as the guiding shafts for the sliding motion of said lens holder, wherein said guidance steel shafts are disposed beside said inner rims of guiding faces and respectively keep spacing to the outer rim of said movable magnetic part via said guiding faces, and said leakage magnetic field created by said moving magnetic part crosses said spacing to interlink said guidance steel shafts to form closed magnetic loops to generate said pre-loads; and a base, utilized to fix said static electrical part and said plurality of guidance steel shafts to form a non-moving member.