Patent Publication Number: US-2021173226-A1

Title: Camera module

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit under 35 U.S.C. § 119(a) of Korean Patent Application No. 10-2019-0164184 filed on Dec. 10, 2019 and Korean Patent Application No. 10-2020-0001061 filed on Jan. 3, 2020, in the Korean Intellectual Property Office, the entire disclosures of which are incorporated herein by reference for all purposes. 
     BACKGROUND 
     1. Field 
     The following description relates to a camera module. 
     2. Description of Related Art 
     Recently, a camera module has been employed in mobile communication terminals such as smartphones, tablet PCs, and laptop computers, and such a camera module may include an autofocusing (AF) function and an optical image stabilization (OIS) function. 
     To implement an AF function and an OIS function, an actuator that may move a lens module in an optical axis direction and a direction perpendicular to the optical axis direction may be required. A VCM actuator using electromagnetic force generated by a magnet and a coil may be used as such an actuator. 
     In the case of an AF actuator, a yoke configured to prevent magnetic flux leakage may be installed on an external side of a coil, and attractive force may be generated between a magnet and the yoke. A ball member configured to guide movement of the lens module during AF may be disposed between the magnet and the coil, and the magnet may receive compressive force working towards the coil (and the yoke) by the attractive force between the magnet and the yoke. Accordingly, the magnet may move in an optical axis direction while being in close contact with the ball member, such that AF may be implemented. 
     However, as an OIS actuator may implement an OIS function by changing a spacing (e.g., a spacing in a direction perpendicular to an optical axis direction) between a magnet and a coil, it may be difficult to arrange a yoke on an external side of the coil. 
     Therefore, in contrast to an AF actuator, an OIS actuator may have a problem of leakage of magnetic flux, which may cause interference with electronic components disposed around a camera module. 
     SUMMARY 
     This Summary is provided to introduce a selection of concepts in simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. 
     In one general aspect, a camera module includes: a housing in which a lens module is accommodated; and a shake correction portion including first and second movable yokes mounted on the lens module and first and second coil portions disposed to oppose the first and second movable yokes, respectively. The first coil portion is configured to attract the first movable yoke in response to power being applied to the first coil portion. The second coil portion is configured to attract the second movable yoke in response to power being applied to the second coil portion. 
     The first and second movable yokes may be formed of a material magnetized by magnetic fields of the first and second coil portions. 
     The first coil portion and the second coil portion may each include two coils disposed in a direction perpendicular to an optical axis. 
     The first movable yoke and the second movable yoke may be configured to move in a direction perpendicular to the optical axis, in response to power being individually applied to the first coil portion and the second coil portion. 
     The first coil portion may include a first coil and a second coil disposed along a first axis perpendicular to an optical axis. The second coil portion may include a third coil and a fourth coil disposed along a second axis perpendicular to the optical axis and the first axis. 
     A portion of each of the first coil and the second coil may be disposed to face the first movable yoke. A portion of each of the third coil and the fourth coil may be disposed to face the second movable yoke. 
     A first plurality of yokes may be disposed in positions corresponding to the first coil and the second coil on an external side of the first coil portion. A second plurality of yokes may be disposed in positions corresponding to the third coil and the fourth coil on an external side of the second coil portion. 
     The camera module may be configured to detect a position of the lens module through changes in inductance of the first and second coil portions according to movement of the first and second movable yokes. 
     An inductance value of the first coil and an inductance value of the second coil may increase or decrease in opposite directions according to the movement of the first movable yoke. An inductance value of the third coil and an inductance value of the fourth coil may increase or decrease in opposite directions according to the movement of the second movable yoke. 
     A length of the first movable yoke in a direction of the first axis may be shorter than a length of the first coil portion in the direction of the first axis. A length of the second movable yoke in a direction of the second axis may be shorter than a length of the second coil portion in the direction of the second axis. 
     In a state in which power is not applied to the first coil portion, a center of the first movable yoke may be disposed between the first coil and the second coil. In a state in which power is not applied to the second coil portion, a center of the second movable yoke may be disposed between the third coil and the fourth coil. 
     The camera module may further include a carrier accommodated in the housing. The carrier may include the lens module and a frame configured to guide movement of the lens module. 
     The camera module may further include: a first ball member disposed between the carrier and the frame; and a second ball member disposed between the frame and the lens module. The first ball member may be disposed to roll in a first axis direction so as to guide movement of the frame and the lens module in the first axis direction. The second ball member may be disposed to roll in a second axis direction so as to guide movement of the lens module in the second axis direction. The first axis direction may be perpendicular to an optical axis, and the second axis direction may be perpendicular to the optical axis and the first axis direction. 
     The camera module may further include: a pulling magnet disposed in one of the carrier and the lens module; and a pulling yoke disposed in the other one of the carrier and the lens module. Magnetic attractive force may act in an optical axis direction between the pulling magnet and the pulling yoke. 
     In another general aspect, a camera module includes: a carrier in which a lens module is accommodated; a housing in which the lens module and the carrier are accommodated; a focus adjustment portion including a magnet disposed in the carrier and a coil disposed to face the magnet; and a shake correction portion including first and second movable yokes mounted on the lens module and first and second coil portions disposed to face the first and second movable yokes, respectively. The first and second movable yokes are formed of a material magnetized by magnetic fields of the first and second coil portions. The first coil portion and the second coil portion each include two coils disposed in a direction perpendicular to an optical axis. The first movable yoke is configured to move in two directions along a first axis perpendicular to the optical axis in response to a magnetic field of the first coil portion. The second movable yoke is configured to move in two directions along a second axis perpendicular to both the optical axis and the first axis in response to a magnetic field of the second coil portion. 
     A portion of each of the two coils of the first coil portion may be disposed to face the first movable yoke. A portion of each of the two coils of the second coil portion may be disposed to face the second movable yoke. 
     A first plurality of yokes may be disposed in positions corresponding to the two coils of the first coil portion on an external side of the first coil portion. A second plurality of yokes may be disposed in positions corresponding to the two coils of the second coil portion on an external side of the second coil portion. 
     Other features and aspects will be apparent from the following detailed description, the drawings, and the claims. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view illustrating a camera module, according to an embodiment. 
         FIG. 2  is an exploded perspective view illustrating the camera module of  FIG. 1 , according to an embodiment. 
         FIG. 3  is a plan view illustrating the camera module of  FIG. 1 , according to an embodiment. 
         FIG. 4  is a view illustrating a dispositional relationship between first and second movable yokes and first and second coil portions of the camera module of  FIG. 1 , according to an embodiment. 
         FIG. 5  is an exploded perspective view illustrating a lens module, a frame, and a carrier of the camera module of  FIG. 1 , according to an embodiment. 
     
    
    
     Throughout the drawings and the detailed description, the same reference numerals refer to the same elements. The drawings may not be to scale, and the relative size, proportions, and depiction of elements in the drawings may be exaggerated for clarity, illustration, and convenience. 
     DETAILED DESCRIPTION 
     The following detailed description is provided to assist the reader in gaining a comprehensive understanding of the methods, apparatuses, and/or systems described herein. However, various changes, modifications, and equivalents of the methods, apparatuses, and/or systems described herein will be apparent after an understanding of the disclosure of this application. For example, the sequences of operations described herein are merely examples, and are not limited to those set forth herein, but may be changed as will be apparent after an understanding of the disclosure of this application, with the exception of operations necessarily occurring in a certain order. Also, descriptions of features that are known in the art may be omitted for increased clarity and conciseness. 
     The features described herein may be embodied in different forms, and are not to be construed as being limited to the examples described herein. Rather, the examples described herein have been provided merely to illustrate some of the many possible ways of implementing the methods, apparatuses, and/or systems described herein that will be apparent after an understanding of the disclosure of this application. 
     Herein, it is noted that use of the term “may” with respect to an embodiment or example, e.g., as to what an embodiment or example may include or implement, means that at least one embodiment or example exists in which such a feature is included or implemented while all examples and examples are not limited thereto. 
     Throughout the specification, when an element, such as a layer, region, or substrate, is described as being “on,” “connected to,” or “coupled to” another element, it may be directly “on,” “connected to,” or “coupled to” the other element, or there may be one or more other elements intervening therebetween. In contrast, when an element is described as being “directly on,” “directly connected to,” or “directly coupled to” another element, there can be no other elements intervening therebetween. 
     As used herein, the term “and/or” includes any one and any combination of any two or more of the associated listed items. 
     Although terms such as “first,” “second,” and “third” may be used herein to describe various members, components, regions, layers, or sections, these members, components, regions, layers, or sections are not to be limited by these terms. Rather, these terms are only used to distinguish one member, component, region, layer, or section from another member, component, region, layer, or section. Thus, a first member, component, region, layer, or section referred to in examples described herein may also be referred to as a second member, component, region, layer, or section without departing from the teachings of the examples. 
     Spatially relative terms such as “above,” “upper,” “below,” and “lower” may be used herein for ease of description to describe one element&#39;s relationship to another element as illustrated in the figures. Such spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, an element described as being “above” or “upper” relative to another element will then be “below” or “lower” relative to the other element. Thus, the term “above” encompasses both the above and below orientations depending on the spatial orientation of the device. The device may also be oriented in other ways (for example, rotated 90 degrees or at other orientations), and the spatially relative terms used herein are to be interpreted accordingly. 
     The terminology used herein is for describing various examples only, and is not to be used to limit the disclosure. The articles “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “includes,” and “has” specify the presence of stated features, numbers, operations, members, elements, and/or combinations thereof, but do not preclude the presence or addition of one or more other features, numbers, operations, members, elements, and/or combinations thereof. 
     Due to manufacturing techniques and/or tolerances, variations of the shapes illustrated in the drawings may occur. Thus, the examples described herein are not limited to the specific shapes illustrated in the drawings, but include changes in shape that occur during manufacturing. 
     The features of the examples described herein may be combined in various ways as will be apparent after gaining an understanding of the disclosure of this application. Further, although the examples described herein have a variety of configurations, other configurations are possible as will be apparent after an understanding of the disclosure of this application. 
       FIG. 1  is a perspective view illustrating a camera module  10 , according to an example embodiment.  FIG. 2  is an exploded perspective view illustrating the camera  10 .  FIG. 3  is a plan view illustrating the camera module  10 . 
     Referring to  FIGS. 1 to 3 , the camera module  10  may include, for example, a lens module  200 , a lens driving device for moving the lens module  200 , and an image sensor module  700  for converting light incident through the lens module  200  into an electric signal, and a housing  110  having the lens module  200  and the lens driving device accommodated therein. 
     The lens module  200  may include a lens barrel  210  and a lens holder  230 . At least one lens for imaging an object may be accommodated in the lens barrel  210 . When a plurality of lenses are disposed in the lens barrel  210 , the plurality of lenses may be disposed in the lens barrel  210  along the optical axis. The lens barrel  210  may have a hollow cylindrical shape, and may be coupled to the lens holder  230 . 
     As an example, the lens driving device may adjust a focus by moving the lens module  200  in the optical axis direction (Z axis direction), and may correct shaking while imaging an object by moving the lens module  200  in a direction (X axis direction and/or Y axis direction) perpendicular to the optical axis (Z axis). 
     The lens driving device may include a focus adjustment portion  400  configured to adjust a focus and a shake correction portion  500  configured to correct shaking. 
     The image sensor module  700  may be a device configured to convert light incident through the lens module  200  into an electric signal. 
     For example, the image sensor module  700  may include an image sensor  710  and a printed circuit board  730  connected to the image sensor  710 , and may further include an infrared filter configured to block light in an infrared range from the light incident through the lens module  200 . 
     The image sensor  710  may convert light incident through the lens module  200  into an electric signal. For example, the image sensor may be implemented by a charge coupled device (CCD) or complementary metal-oxide semiconductor (CMOS). The electrical signal converted by the image sensor  710  may be output as an image through a display unit of a portable electronic device. 
     The image sensor  710  may be fixed to the printed circuit board  730  and may be electrically connected to the printed circuit board  730  by wire bonding. 
     The lens module  200  may be accommodated in the housing  110 . For example, the housing  110  has an open upper portion and an open lower portion, and the lens module  200  may be accommodated in an internal space of the housing  110 . 
     The image sensor module  700  may be disposed below the housing  110 . 
     The case  130  may be coupled to the housing  110  so as to surround an external surface of the housing  110 , and may have a function to protect the internal components of the camera module  10 . 
     The focus adjustment portion  400  of the lens driving device will be described with reference to  FIG. 2 . 
     Referring to  FIG. 2 , the lens driving device may move the lens module  200  to focus on a subject. 
     For example, the camera module  10  may include the focus adjustment portion  400  for moving the lens module  200  in the optical axis direction (Z axis direction). 
     The focus adjustment portion  400  may include a carrier  300  having the lens module  200  accommodated therein, and a magnet  410  and a coil  430  that may generate driving force to move the lens module  200  and the carrier  300  in the optical axis direction (Z axis direction). The magnet  410  and the coil  430  may be disposed to face each other in a direction perpendicular to the optical axis direction (Z axis direction). 
     The magnet  410  may be mounted on the carrier  300 . For example, the magnet  410  may be mounted on one side surface of the carrier  300 . 
     The coil  430  may be disposed on the substrate  600 . For example, the coil  430  may be provided on an internal surface of the substrate  600 . The substrate  600  may be mounted on the housing  110  such that the magnet  410  and the coil  430  face each other in a direction perpendicular to the optical axis (Z axis). The substrate  600  may have a “⊏”-shaped planar shape, and may be mounted on three side surfaces of the housing  110 . 
     The housing  110  may have four side surfaces, and three of the four side surfaces may each have an opening. The substrate  600  may be mounted on three side surfaces of the housing  110  that include the openings. 
     The magnet  410  may be configured as a moving member mounted on the carrier  300  and configured to move in the optical axis direction (Z axis direction) along with the carrier  300 . The coil  430  may be a fixed member fixed to the housing  110 . 
     When power is applied to the coil  430 , the carrier  300  may move in the optical axis direction (Z axis direction) by electromagnetic force between the magnet  410  and the coil  430 . For example, when power is applied to the coil  430 , driving force may be generated in the direction of the optical axis (Z axis) by the magnet  410  and the coil  430 . 
     Since the lens module  200  is accommodated in the carrier  300 , the lens module  200  may also move in the optical axis direction (Z axis direction) by the movement of the carrier  300 . Since the frame  310  and the lens module  200  are accommodated in order in the carrier  300 , the frame  310  and the lens module  200  may also move in the direction of the optical axis (Z axis) by the movement of the carrier  300 . 
     A rolling member B 1  may be disposed between the carrier  300  and the housing  110  to reduce friction between the carrier  300  and the housing  110  when the carrier  300  moves. The rolling member B 1  may have a ball shape. 
     Rolling members B 1  may be disposed on both sides of the magnet  410 . 
     The yoke  450  may be disposed to face the magnet  410  in a direction perpendicular to the optical axis (Z axis). The yoke  450  may be mounted on the external surface of the substrate  600 . For example, the yoke  450  may be disposed to face the magnet  410  with the coil  430  being disposed between the yoke  450  and the magnet  410 . 
     The attractive force between the yoke  450  and the magnet  410  may work in a direction perpendicular to the optical axis (Z axis). 
     Accordingly, the rolling member B 1  may maintain a state of contact with the carrier  300  and the housing  110  by the attractive force between the yoke  450  and the magnet  410 . 
     The yoke  450  may also have a function to focus the magnetic force of the magnet  410 . Accordingly, leakage of magnetic flux may be prevented. For example, the yoke  450  and the magnet  410  may form a magnetic circuit. 
     A closed-loop control method may be implemented for sensing a position of the lens module  200  and providing feedback of the position. Accordingly, a position sensor  470  may be provided for the closed-loop control. The position sensor  470  may be disposed in a hollow portion formed in a center of the coil  430  to face the magnet  410 . The position sensor  470  may be configured as a hall sensor. 
     In the description below, the shake correction portion  500  of the lens driving apparatus will be described. 
     The shake correction portion  500  may be used to correct blurring of an image or shaking of a video caused by factors such as hand-shake of a user while an image or a video is obtained. For example, when shaking occurs by the hand-shake of a user while an image is obtained, the shake correction portion  500  may provide relative displacement corresponding to shaking to the lens module  200 , thereby compensating for shaking. For example, the shake correction portion  500  may correct shaking by moving the lens module  200  in a direction perpendicular to the optical axis (Z axis). 
     The shake correction portion  500  may include a frame  310  configured to guide the movement of the lens module  200 , a first movable yoke  510   a  and a first coil portion  510   b,  and a second movable yoke  530   a  and a second coil portion  530   b  that may generate driving force in a direction perpendicular to the optical axis (Z axis). 
     The first and second movable yokes  510   a  and  530   a  may be mounted on the lens module  200 . For example, the first movable yoke  510   a  may be mounted on one side surface of the lens holder  230 , and the second movable yoke  530   a  may be mounted on the other side surface of the lens holder  230 . 
     The first movable yoke  510   a  and the second movable yoke  530   a  may be disposed perpendicular to each other. 
     The first and second movable yokes  510   a  and  530   a  may be formed of a metal. Also, the first and second movable yokes  510   a  and  530   a  may be formed of a material magnetized by magnetic fields of the first and second coil portions  510   b  and  530   b.  For example, the first and second movable yokes  510   a  and  530   a  may be formed of a magnetic material including any one or any combination of any two or more of iron, nickel, and cobalt. The first and second movable yokes  510   a  and  530   a  may be a magnetic material, rather than a magnet (permanent magnet). 
     Each of the first and second coil portions  510   b  and  530   b  may include two coils. As an example, the first coil portion  510   b  may include a first coil  510   c  and a second coil  510   d  disposed in-line along a first axis direction (X axis direction) perpendicular to the optical axis (Z axis), and the second coil portion  530   b  may include a third coil  530   c  and a fourth coil  530   d  disposed in-line along a second axis direction (Y axis direction) perpendicular to both the optical axis (Z axis) and the first axis (X axis). 
     The first and second coil portions  510   b  and  530   b  may be provided on the internal surface of the substrate  600 . The substrate  600  may have a “⊏”-shaped planar shape, and the coil  430 , the first coil portion  510   b,  and the second coil portion  530   b  may be disposed on three internal surfaces. 
     The first movable yoke  510   a  may be disposed to face the first coil portion  510   b  in the second axis direction (Y axis direction) perpendicular to the optical axis (Z axis), and the second movable yoke  530   a  may be disposed to face the coil portion  530   b  in the first axis direction (X axis direction) perpendicular to the optical axis (Z axis). 
     In the focus adjustment portion  400 , driving force may be generated by interaction between the magnet  410  and the coil  430 , and the shake correction portion  500  may generate driving force by an attractive force formed by magnetic fields of the first and second coil portions  510   b  and  530   b.    
     A method of generating the driving force of the shake correction portion  500  will be described later with reference to  FIG. 4 . 
     The frame  310  and the lens holder  230  may be disposed in order in the carrier  300  in the optical axis direction (Z axis direction), and may be configured to guide the movement of the lens barrel  210 . The frame  310  and the lens holder  230  may have a space in which the lens barrel  210  may be inserted. The lens barrel  210  may be inserted into and fixed to the lens holder  230 . 
     The frame  310  and the lens holder  230  may move in a direction perpendicular to the optical axis (Z axis) by the attractive force formed by the magnetic fields of the first and second coil portions  510   b  and  530   b  with respect to the carrier  300 . 
     The first movable yoke  510   a  may be drawn toward the first coil portion  510   b  by the attractive force formed by the magnetic field of the first coil portion  510   b,  and the second movable yoke  530   a  may be drawn toward the second coil portion  530   b  by the attractive force formed by the magnetic field of the second coil portion  530   b.    
     For example, the first movable yoke  510   a  may move in the first axis direction (X axis direction) perpendicular to the optical axis (Z axis) by the attraction force formed by the magnetic field of the first coil portion  510   b,  and the second movable yoke  530   a  may move in the second axis direction (Y-axis direction) perpendicular to the first axis direction (X-axis direction) by the attraction force formed by the magnetic field of the second coil portion  530   b.    
     Accordingly, the first movable yoke  510   a  may move in a direction perpendicular to the direction facing the first coil portion  510   b,  the second movable yoke  530   a  may move in a direction perpendicular to the direction facing the second coil portion  530   b.    
     The second axis direction (Y axis direction) may be a direction perpendicular to both the optical axis (Z axis) direction and the first axis (X axis) direction. 
     The camera module  10  may include a plurality of ball members for supporting the frame  310  and the lens holder  230 . The plurality of ball members may guide the movement of the frame  310 , the lens holder  230 , and the lens barrel  210  during the shake correction process, and may also maintain a gap among the carrier  300 , the frame  310  and the lens holder  230 . The plurality of ball members may include a first ball member B 2  and a second ball member B 3 . 
     The first ball member B 2  may guide the movement of the frame  310 , the lens holder  230 , and the lens barrel  210  in the first axis direction (X-axis direction), and the second ball member B 3  may guides the movement of the lens holder  230  and the lens barrel  210  in the second direction (Y-axis direction). 
     As an example, the first ball member B 2  may roll in the first direction (X-axis direction) when driving force in the first direction (X-axis direction) is generated. Accordingly, the first ball member B 2  may guide the movement of the frame  310 , the lens holder  230 , and the lens barrel  210  in the first direction (X-axis direction). 
     The second ball member B 3  may roll in the second direction (Y-axis direction) when driving force is generated in the second direction (Y-axis direction). Accordingly, the second ball member B 3  may guide the movement of the lens holder  230  and the lens barrel  210  in the second direction (Y-axis direction). 
     A plurality of first ball members B 2  may be disposed between the carrier  300  and the frame  310 , and a plurality of second ball members B 3  may be disposed between the frame  310  and the lens holder  230 . 
     A first guide groove portion  301  configured to accommodate the first ball member B 2  may be formed on at least one of the surfaces of the carrier  300  and the frame  310  facing each other in the optical axis direction (Z axis direction). The first guide groove portion  301  may include a plurality of first guide grooves corresponding to the plurality of first ball members B 2 . 
     The first ball members B 2  may be respectively accommodated in the first guide grooves of the first guide groove portion  301  and fitted between the carrier  300  and the frame  310 . In a state in which the first ball members B 2  are accommodated in the first guide grooves of the first guide groove portion  301 , movement of the first ball members B 2  in the optical axis direction (Z axis direction) and the second axis direction (Y axis direction) may be prevented, and the first ball members B 2  may only move in the first axis direction (X axis direction). For example, the first ball members B 2  may only roll in the first axis direction (X axis direction). Accordingly, the planar shape of each of the first guide grooves of the first guide groove portion  301  may be a rectangular shape having a length (e.g., a longest side) in the first axis direction (X axis direction). 
     A second guide groove portion  311  for accommodating the second ball member B 3  may be formed on at least one of the surfaces of the frame  310  and the lens holder  230  facing each other in the optical axis direction (Z axis direction). The second guide groove portion  311  may include a plurality of second guide grooves corresponding to the plurality of second ball members B 3 . 
     The second ball members B 3  may be respectively accommodated in the second guide grooves of the second guide groove portion  311  and may be inserted between the frame  310  and the lens holder  230 . 
     In a state in which the second ball members B 3  are accommodated in the second guide grooves of the second guide groove portion  311 , movement of the second ball members B 3  in the optical axis direction (Z axis direction) and the first axis direction (X axis direction) may be prevented, and the second ball members B 3  may only move in the second axis direction (Y axis direction). As an example, the second ball members B 3  may only roll in the second axis direction (Y axis direction). Accordingly, the planar shape of each of the second guide grooves of the second guide groove portion  311  may be a rectangular shape having a length (e.g., a longest side) in the second axis direction (Y axis direction). 
     When driving force is generated in the first axis direction (X axis direction), the frame  310 , the lens holder  230 , and the lens barrel  210  may move together in the first axis direction (X axis direction). The first ball members B 2  may roll along the first axis direction (X axis direction). In this case, the movement of the second ball members B 3  may be prevented. 
     Also, when driving force is generated in the second axis direction (Y axis direction), the lens holder  230  and the lens barrel  210  may move in the second axis direction (Y axis direction). The second ball members B 3  may roll along the second axis direction(Y axis direction). In this case, the movement of the first ball members B 2  may be prevented. 
       FIG. 4  is a view illustrating a dispositional relationship between the first and second movable yokes  510   a  and  530   a,  and the first and second coil portions  510   b  and  530   b.    
     Referring to  FIG. 4 , first and second movable yokes  510   a  and  530   a  may be mounted on the lens holder  230 . The first movable yoke  510   a  and the second movable yoke  530   a  may be disposed perpendicular to each other. The first coil portion  510   b  may be disposed to face the first movable yoke  510   a,  and the second coil portion  530   b  may be disposed to face the second movable yoke  530   a.    
     The first coil portion  510   b  may include the first coil  510   c  and a second coil  510   d  disposed in-line along the first axis direction (X axis direction). A length (in the first axis direction) of the first movable yoke  510   a  may be shorter than a length (in the first axis direction) of the first coil portion  510   b.  As an example, a portion of each of the first coil  510   c  and the second coil  510   d  may face the first movable yoke  510   a.  In a state in which power is not applied to the first coil portion  510   b,  a center of the first movable yoke  510   a  may be disposed between the first coil  510   c  and the second coil  510   d,  and a portion of each of the first coil  510   c  and the second coil  510   d  may be disposed to face the first movable yoke  510   a.    
     The second coil portion  530   b  may include the third coil  530   c  and the fourth coil  530   d  disposed in-line along the second axis direction (Y axis direction). A length of the second movable yoke  530   a  (in the second axis direction) may be shorter than a length of the second coil portion  530   b  (in the second axis direction). For example, a portion of each of the third coil  530   c  and the fourth coil  530   d  may face the second movable yoke  530   a.  In a state in which power is not applied to the second coil portion  530   b,  a center of the second movable yoke  530   a  may be disposed between the third coil  530   c  and the fourth coil  530   d,  and a portion of each of the third coil  530   c  and the fourth coil  530   d  may be disposed to face the second movable yoke  530   a.    
     Since the first movable yoke  510   a  is formed of a magnetic material, rather than a magnet (permanent magnet), when power is not applied to the first coil portion  510   b,  the first coil portion  510   b  may not attract the first movable yoke  510   a.  However, when power is applied to the first coil portion  510   b,  a magnetic field may be formed around the first coil portion  510   b  and, accordingly, the first coil portion  510   b  may pull the first movable yoke  510   a.    
     A length (in the first axis direction) of the first movable yoke  510   a  may be shorter than a length (in the first axis direction) of the first coil portion  510   b.  Accordingly, when power is applied to the first coil  510   c,  the first movable yoke  510   a  may be drawn toward the first coil  510   c  by the magnetic field of the first coil  510   c,  and, when power is applied to the second coil  510   d,  the first movable yoke  510   a  may be drawn toward the second coil  510   d  by the magnetic field of the second coil  510   d.    
     In other words, when power is applied to the first coil portion  510   b,  the first movable yoke  510   a  may move in the first axis direction (X axis direction) by the magnetic field of the first coil portion  510   b.  Since the first coil portion  510   b  includes the first coil  510   c  and the second coil  510   d  disposed in-line along the first axis direction (X axis direction), the first movable yoke  510   a  may move in both directions along the first axis (X axis). 
     Since the second movable yoke  530   a  is formed of a magnetic material, rather than a magnet (permanent magnet), when power is not applied to the second coil portion  530   b,  the second coil portion  530   b  may not attract the second movable yoke  530   a.  However, when power is applied to the second coil portion  530   b,  a magnetic field may be formed around the second coil portion  530   b  and, accordingly, the second coil portion  530   b  may pull the second movable yoke  530   a.    
     A length (in second axis direction) of the second movable yoke  530   a  may be shorter than a length (in second axis direction) of the second coil portion  530   b.  Accordingly, when power is applied to the third coil  530   c,  the second movable yoke  530   a  may be drawn toward the third coil  530   c  by the magnetic field of the third coil  530   c,  and, when power is applied to the fourth coil  530   d,  the second movable yoke  530   a  may be drawn toward the fourth coil  530   d  by the magnetic field of the fourth coil  530   d.    
     In other words, when power is applied to the second coil portion  530   b,  the second movable yoke  530   a  may move in the second axis direction (Y axis direction) by the magnetic field of the second coil portion  530   b.  Since the second coil portion  530   b  includes the third coil  530   c  and the fourth coil  530   d  disposed in-line along the second axis direction (Y axis direction), the second movable yoke  530   a  may move in both directions towards the second axis (Y axis). 
     A plurality of yokes  510   e,    510   f,    530   e,  and  530   f  may be disposed on external sides of the first and second coil portions  510   b  and  530   b.  For example, the plurality of yokes  510   e,    510   f,    530   e,  and  530   f  may be mounted on the external surface of the substrate  600 . The plurality of yokes  510   e  and  510   f  may include a pair of yokes  510   e  and  510   f  corresponding to the first coil portion  510   b  and a pair of yokes  510   e  and  510   f  corresponding to the second coil portion  530   b.    
     Each pair of yokes  510   e  and  510   f  may be disposed to face the first and second movable yokes  510   a  and  530   a,  respectively, in a direction perpendicular to the optical axis (Z axis). For example, each pair of yokes  510   e  and  510   f,  may be disposed to face the first and second movable yokes  510   a  and  530   a,  respectively, with the first and second coil portions  510   b  and  530   b  respectively interposed therebetween. 
     The plurality of yokes  510   e  and  510   f  may prevent leakage of magnetic flux of the first and second coil portions  510   b  and  530   b.    
     In contrast to the focus adjustment portion  400 , attractive force may not work between the first and second movable yoke  510   a  and  530   a  and the plurality of yokes  510   e  and  510   f.  Accordingly, the movement of the first and second movable yokes  510   a  and  530   a  may not be disturbed by the plurality of yokes  510   e  and  510   f.    
     Also, since a magnet is not used for an actuator for shake correction, and the first and second movable yokes  510   a  and  530   a  may be used, and also as the plurality of yokes  510   e  and  510   f  are disposed on external sides of the first and second coil portions  510   b  and  530   b,  leakage of magnetic flux may be prevented. 
       FIG. 5  is an exploded perspective view illustrating the lens module  200 , the frame  310 , and the carrier  300  of the camera module  10 , according to an embodiment. 
     Referring to  FIG. 5 , in the camera module  10 , a pulling yoke  830  and a pulling magnet  810  may be provided such that the shake correction portion  500  and first and second ball members B 2  and B 3  may maintain a state of contact therebetween. The pulling yoke  830  may be mounted on one of the carrier  300  and the lens module  200 , and the pulling magnet  810  may be mounted on the other one of the carrier  300  and the lens module  200 . 
     For example, the pulling yoke  830  may be fixed to the carrier  300 , and the pulling magnet  810 , which faces the pulling yoke  830  in the optical axis direction (Z axis direction), may be disposed on the lens module  200 . 
     Accordingly, magnetic attractive force may be generated between the pulling yoke  830  and the pulling magnet  810  in the optical axis direction (Z axis direction). 
     The shaking correction portion  500  and the first and second ball members B 2  and B 3  may maintain a state of contact due to magnetic attractive force between the pulling yoke  830  and the pulling magnet  810  even when power is not applied to the first and second coil portions  510   b  and  530   b,  and the lens module  200  may be positioned at a predetermined initial position. 
     Since the lens holder  230  and the frame  310  are pressed in the direction toward the pulling yoke  830  by magnetic attractive force between the pulling yoke  830  and the pulling magnet  810 , the frame  310  and the lens holder The  230  may maintain a state of contact with the first and second ball members B 2  and B 3 . 
     In the example embodiment, a closed-loop control method for sensing the position of the lens barrel  210  in the shake correction process and providing a feedback of the position may be implemented. 
     Therefore, a position sensor may be provided for the closed-loop control, and the position sensor may be a hall sensor. The position sensor may be disposed on the carrier  300  to face the pulling magnet  810  in the optical axis direction (Z axis direction). 
     In contrast to the above-described configuration, a position sensor may not be provided and, in this case, positions of the first and second movable yokes  510   a  and  530   a  may be detected through changes in inductance of the first coil portion  510   b  and the second coil portion  530   b.    
     For example, as the first and second movable yokes  510   a  and  530   a  move, the inductance of the first and second coil portions  510   b  and  530   b  may change. Accordingly, the positions of the first and second movable yokes  510   a  and  530   a  may be detected through changes in inductance of the first and second coil portions  510   b  and  530   b.    
     Since the first and second movable yokes  510   a  and  530   a  are mounted on the lens module  200  and move together with the lens module  200 , position of the lens module  200  may be detected through changes in inductance of the first and second coil portions  510   b  and  530   b.    
     The first coil portion  510   b  may include the first coil  510   c  and the second coil  510   d  disposed along the first axis (X axis). When the first movable yoke  510   a  moves along the first axis (X axis), an inductance value of the first coil  510   c  and an inductance value of the second coil  510   d  may increase or decrease in opposite directions. 
     Accordingly, by differentiating the inductance value of the first coil  510   c  and the inductance value of the second coil  510   d,  the influence of disturbance due to temperature change of the surrounding environment may be removed, and the position of the lens module  200  may be accurately detected. 
     The second coil portion  530   b  may include the third coil  530   c  and the fourth coil  530   d  disposed along the second axis (Y axis). When the second movable yoke  530   a  moves along the second axis (Y axis), the inductance value of the third coil  530   c  and the inductance value of the fourth coil  530   d  may increase or decrease in opposite directions. 
     Accordingly, by differentiating the inductance value of the third coil  530   c  and the inductance value of the fourth coil  530   d,  the influence of disturbance due to temperature change of the surrounding environment may be removed, and a position of the lens module  200  may be accurately detected. 
     The camera module  10  may include a stopper  330  ( FIG. 1 ) to prevent the first and second ball members B 2  and B 3 , the frame  310 , and the lens module  200  from being detached to the outside of the carrier  300 . The stopper  330  may be coupled to the carrier  300  to cover at least a portion of the upper surface of the lens holder  230 . 
     According to the embodiments disclosed herein, a camera module may prevent magnetic flux leakage. 
     While this disclosure includes specific examples, it will be apparent after an understanding of the disclosure of this application that various changes in form and details may be made in these examples without departing from the spirit and scope of the claims and their equivalents. The examples described herein are to be considered in a descriptive sense only, and not for purposes of limitation. Descriptions of features or aspects in each example are to be considered as being applicable to similar features or aspects in other examples. Suitable results may be achieved if the described techniques are performed in a different order, and/or if components in a described system, architecture, device, or circuit are combined in a different manner, and/or replaced or supplemented by other components or their equivalents. Therefore, the scope of the disclosure is defined not by the detailed description, but by the claims and their equivalents, and all variations within the scope of the claims and their equivalents are to be construed as being included in the disclosure.