Patent ID: 8390946
Filing Date: 2013-03-05
Classification: G02B,H02K

Abstract:
1. An electromagnetic lens driving device, defining a central axis and comprising: a casing forming a receiving space; an upper cover connected to the casing; a lens module received in the receiving space and further having a lens and a lens mount, the lens being provided in the lens mount and synchronously movable with the lens mount; an electromagnetic driving module provided in the receiving space and connected between the lens module and the casing, the electromagnetic driving module comprising a plurality of magnets and a coil, wherein when currents of different directions flow through the coil, the coil generates magnetic fields of different polarities that cause magnetic attraction or repulsion between the plural magnets and the coil, thereby driving the lens module to move in the receiving space along the central axis; and a positioning structure connected between the lens module and the casing, the positioning structure being configured to limit the lens module within the receiving space and generate a frictional force, wherein when the currents flowing through the coil cease, the lens module is fixed in position by the frictional force of the positioning structure and is therefore prevented from moving freely; the positioning structure further including: a first guide shaft, extending parallel to the central axis and having two ends respectively and fixedly connected to the upper cover and the casing such that the first guide shaft is connected therebetween, and a resilient pre-stressed element, formed as a curved U-shaped claw having two hook members extending from a pivot end pivotally mounted around the first guide shaft with such tightness that the frictional force is generated at a contact surface between the pivot end and the first guide shaft, the two hook members spaced apart by a predetermined distance and being engaged individually with a fixing end protruding from an outer periphery of the lens mount, the predetermined distance being greater than or equal to a width of the coil.