Patent ID: 7944636

Claim:
A lens driving device, comprising: a lens holder for holding at least one lens; a driving coil installed on an outer sidewall of said lens holder and wound around an optical axis of the lens; at least one permanent magnet arranged in proximity of an outer circumference of said driving coil and spaced-apart from said driving coil; a casing for holding said permanent magnet; and spring members connecting with said lens holder and said casing; wherein when said driving coil is not powered, compressive stress of said spring members causes said lens holder to prop against said casing at a side opposite to an imaged object, while when said driving coil is powered, said lens holder is moved toward said imaged object, said lens driving device is characterized in that: when said driving coil is not powered, the magnitude of driving magnetic field intersecting with said driving coil at a position of said driving coil in a direction parallel to said optical axis of the lenses is 50%˜90% of a maximum value of the driving magnetic field intersecting with said driving coil while said lens holder moves toward the imaged object.