Moving-coil closed-loop auto-focusing camera module with low magnetic interference

Abstract

A moving-coil closed-loop auto-focusing module with low magnetic interference includes an upper cover, a base frame, a lens module, an elastic module, at least one coil, at least one pair of two opposing driving magnets, an external circuit and at least one sensor magnet. The coil surrounds the lens module. The two driving magnets are located individually at respective lateral sides of the base frame in correspondence with the coil. The external circuit located under the base frame includes an image-sensing element and at least one sensor. The sensor magnet is mounted peripherally to the lens module, and has magnetic lines parallel to the optical image-capturing axis, such that a magnetizing surface of the sensor magnet can face downward to align the sensor on the external circuit. Thereupon, the lens module can be controlled to displace along an optical image-capturing axis in a closed-loop manner.

1 - 16 . (canceled) 
     
     
         17 . A closed-loop auto-focusing module, defined with an X axis, a Y axis and a Z axis perpendicular to each other, having an optical axis parallel to the Z axis, comprising:
 a lens carrier, capable of carrying a lens set, said lens set defining said optical axis;   an external circuit, located under the lens carrier along the Z axis;   at least one driving module, for driving the lens carrier to move relative to the external circuit at least along the Z axis;   at least one position sensor, located on the external circuit; and   a sensor magnet, located at the lens carrier;   characterized by that:   said sensor magnet being a dipolar sensor magnet with a magnetizing direction parallel to the optical axis; said sensor magnet having a magnetizing surface thereof to face downward along the Z axis to correspond to the at least one position sensor on the external circuit, so that said at least one position sensor is able to detect magnetism of the sensor magnet for detecting a relative displacement between the lens carrier and the external circuit.   
     
     
         18 . The closed-loop auto-focusing module of  claim 17 , wherein the sensor magnet has two opposing polarities to different sides thereof and is either built integrally as a unique piece or consisted of two monopolar sensor magnets; the sensor magnet is either symmetrically or asymmetrically magnetized; said position sensor is a Hall sensor; said Hall sensor is to detect magnetism of the sensor magnet for detecting the relative displacement along the Z axis between the lens carrier and the external circuit. 
     
     
         19 . The closed-loop auto-focusing module of  claim 17 , further comprising:
 an upper cover, including a through hole;   a base frame, engaging the upper cover to form an internal accommodation space;   a lens module, located inside the accommodation space;   an elastic module, clamping the lens module, confining the lens module to be slidable along the optical axis within the accommodation space;   at least one coil, surrounding the lens module; and   at least one pair of two opposing driving magnets, mounted on respective lateral sides of the base frame in correspondence with the coil;   wherein:   said at least one driving module comprises said at least one coil and said at least one pair of two opposing driving magnets;   said external circuit is located under the base frame and includes an image-sensing element and said at least one position sensor;   the lens module includes said lens set and said lens carrier, the lens set is located in a central place of the lens carrier to displace synchronously with the lens carrier;   the driving magnet is one of a monopolar driving magnet and a dipolar driving magnet; polarities of the driving magnet is the same or contrary when the driving magnet is the dipolar driving magnet; the driving magnet is either symmetrically or asymmetrically magnetized when the driving magnet is the dipolar driving magnet;   the coil is one of the following: an annular monopole coil, an annular dipolar coil, a plate-type dipolar coil and a printed circuit board (PCB);   the at least one pair of two opposing driving magnets includes two said pairs of two opposing driving magnets, wherein each said pair includes two driving magnets; said two pairs of two opposing driving magnets are either individually and evenly mounted into respective lateral mounting grooves at corresponding lateral sides of the base frame, or individually mounted to respective corners of the base frame;   
     
     
         20 . The closed-loop auto-focusing module of  claim 19 , further including a yoke mounted between the sensor magnet and the lens module. 
     
     
         21 . The closed-loop auto-focusing module of  claim 19 , wherein the pairs of two opposing driving magnets are all the dipolar driving magnets with the same or different polarities;
 wherein, when the two pairs of two opposing driving magnets are all the dipolar driving magnets with the same polarity, a magnetic pole of each of the driving magnets that faces the lens module is one of an N/S-pole and an S/N-pole;   wherein, when two pairs of two opposing driving magnets are all the dipolar driving magnets with different polarities, magnetic poles of the driving magnets that face the lens module are intermittently set between N/S-poles and S/N-poles.   
     
     
         22 . The closed-loop auto-focusing module of  claim 19 , wherein the driving magnets include two opposing main driving magnets and two opposing auxiliary driving magnets; the sensor magnet is mounted on the lens module in correspondence with one of the two opposing auxiliary driving magnets. 
     
     
         23 . The closed-loop auto-focusing module of  claim 22 , wherein one of the two opposing auxiliary driving magnets is further cut into halves to produce another two auxiliary driving magnet having the same volume, and the dipolar sensor magnet is located at a place between said another two auxiliary driving magnets; wherein magnetizing surfaces of the another two auxiliary driving magnets face the sensor magnet, and magnetism of each of the magnetizing surfaces is one of an N-pole and an S-pole. 
     
     
         24 . The closed-loop auto-focusing module of  claim 22 , wherein:
 the two opposing auxiliary driving magnets are both the dipolar driving magnets, and N/S polarities of the two opposing auxiliary driving magnets are the same or different;   when the N/S polarities of the two opposing auxiliary driving magnets are the same, polarities at magnetizing surfaces of the two opposing auxiliary driving magnets that face the lens module are the same;   when the N/S polarities of the two opposing auxiliary driving magnets are different, polarities at the magnetizing surfaces of the two opposing auxiliary driving magnets that face the lens module are different.   
     
     
         25 . The closed-loop auto-focusing module of  claim 19 , wherein:
 the at least one pair of two opposing driving magnets include two opposing main driving magnets and at least one auxiliary driving magnet; the two opposing main driving magnet and the auxiliary driving magnet are continuously mounted into three consecutive and neighbored lateral mounting grooves of the base frame; a volume of the auxiliary driving magnet is smaller than that of the main driving magnet; the auxiliary driving magnet is mounted into the lateral mounting groove of the base frame located right between the two opposing main driving magnets;   the auto-focusing module further includes a plurality of suspension wires and a second electromagnetic driving module; the suspension wire is featured in elastic suspension and electric conduction; the plurality of suspension wires are together to suspend elastically an assembly of the base frame, the lens module, the elastic module, the coil and the driving magnets above the second electromagnetic driving module;   the second electromagnetic driving module further includes a circuit board, two opposing pairs of two collinear X-axial coils, at least one Y-axial coil, a connection plate, a base plate, an X-axial sensor and a Y-axial sensor; the two opposing pairs of two collinear X-axial coils are perpendicular to the at least one Y-axial coil on the circuit board; the X-axial sensor is located between the two collinear X-axial coils in the same pair; the Y-axial sensor is corresponding to the at least one Y-axial coil; the X-axial sensor and the Y-axial sensor are mounted on and thus electrically coupled with the external circuit.   
     
     
         26 . The closed-loop auto-focusing module of  claim 19 , wherein each of the two opposing driving magnets is one of a dipolar main driving magnet and a monopolar main driving magnet, and one of the two opposing driving magnets is cut into halves evenly to produce another two main driving magnets with the same volume located at the same side of the lens module. 
     
     
         27 . The closed-loop auto-focusing module of  claim 25 , wherein the second electromagnetic driving module further includes two corresponded second X-axial sensors and two corresponded second Y-axial sensors; the two corresponded second X-axial sensors are mounted between the two collinear X-axial coils containing no said X-axial sensor so as to detect magnetic fields of the main driving magnets and to derive a tilt angle of the lens module about the Y axis through relevant transformation algorithms; the two corresponded second Y-axial sensors being mounted close to the Y-axial coil so as to detect a magnetic field of the auxiliary driving magnet and to derive another tilt angle of the lens module about the X axis through another relevant transformation algorithms. 
     
     
         28 . The closed-loop auto-focusing module of  claim 19 , wherein the auto-focusing module has a gap surface containing no said driving magnet, and the sensor magnet is mounted on the gap surface. 
     
     
         29 . The closed-loop auto-focusing module of  claim 19 , wherein, said auto-focusing module includes two said position sensors (Hall sensors) individually mounted under the sensor magnet and aside to two opposing ends of the sensor magnet for detecting individually N/S magnetic fields and identifying displacements of the lens module. 
     
     
         30 . The closed-loop auto-focusing module of  claim 19 , wherein said auto-focusing module includes two said sensor magnets; in addition, said at least one position sensor includes two said position sensors located in correspondence with the two sensor magnets; the two position sensors being individually mounted to two opposing lateral sides of the lens module; the two sensor magnets being individually mounted to the two opposing lateral sides of the lens module; the two position sensors are to detect respective N/S magnetic fields of the corresponding two said sensor magnets so as to obtain a tilt angle of the lens module. 
     
     
         31 . The closed-loop auto-focusing module of  claim 19 , wherein said auto-focusing module includes two said sensor magnets; said at least one position sensor includes two said position sensors located in correspondence with the two sensor magnets; the two position sensors are individually mounted to two neighboring lateral sides of the lens module; the two sensor magnets are individually mounted to the two neighboring lateral sides of the lens module; the two position sensors are to detect respective N/S magnetic fields of the corresponding two said sensor magnets so as to correct a position of the lens module. 
     
     
         32 . The closed-loop auto-focusing module of  claim 28 , wherein, when two said auto-focusing modules having the gap surface are integrated into a dual-lens module, the two gap surfaces of the corresponding two said auto-focusing modules are neighbored and face to each other. 
     
     
         33 . The closed-loop auto-focusing module of  claim 25 , wherein the X-axial sensor for detecting X-axial movement of the lens module is mounted aside to the main driving magnet; the Y-axial sensor for detecting the Y-axial movement of the lens module is mounted to a corner of the auxiliary driving magnet.