Patent Publication Number: US-2023140963-A1

Title: Camera module

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 16/823,060 filed on Mar. 18, 2020, which claims the benefit under 35 USC 119(a) of Korean Patent Application Nos. 10-2019-0050936 filed on Apr. 30, 2019, and 10-2019-0092229 filed on Jul. 30, 2019, in the Korean Intellectual Property Office, the entire disclosures of which are incorporated herein by reference for all purposes. 
    
    
     BACKGROUND 
     1. Field 
     This application relates to a camera module. 
     2. Description of Related Art 
     Camera modules have generally been installed in portable electronic devices, such as tablet personal computers (PCs) and laptop computers, in addition to smartphones, and an autofocusing (AF) function, an optical image stabilization (OIS) function, and a zoom function have been added to camera modules for portable electronic devices. 
     To implement such functions, however, structures of camera modules have become complex and sizes of the camera modules have been increased, causing portable electronic devices in which the camera modules are mounted to increase in size. 
     Additionally, in the case of directly moving a lens or an image sensor for optical image stabilization, both the weight of the lens or the image sensor itself and the weights of other members to which the lens or the image sensor is attached need to be taken into consideration. This requires a driving force to be increased, thereby increasing power consumption. 
     Furthermore, to implement the AF and zoom functions, a certain amount of space needs to be provided in an optical axis direction to enable the lens to move in the optical axis direction. However, it may be difficult to implement such a configuration due to the thinness of the camera module. 
     SUMMARY 
     This Summary is provided to introduce a selection of concepts in a 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; a plurality of movable lens modules disposed in an internal space of the housing and configured to be movable in an optical axis direction, each of the plurality of movable lens modules including at least one lens; and a stopper configured to prevent contact between at least two of the plurality of movable lens modules, wherein the stopper includes a frame mounted on the housing; an extension portion extending from the frame into the internal space of the housing to face a side of one movable lens module of the plurality of movable lens modules in the optical axis direction; and a damping member disposed on the extension portion to face the side of the one movable lens module in the optical axis direction. 
     The one movable lens module of the plurality of movable lens modules may be a first movable lens module, another one of the plurality of movable lens modules may be a second movable lens module disposed adjacent to the first movable lens module in the optical axis direction, the second lens module may include a space portion formed by removing a portion of the second lens module facing the first lens module in the optical axis direction, and the extension portion and the damping member may extend into the space portion of the second lens module to face the side of the first movable lens module in the optical axis direction. 
     The stopper may further include a first stopper configured to limit a movement of the first lens module in the optical axis direction; and a second stopper configured to limit a movement of the second lens module in the optical axis direction, wherein the frame, the extension portion, and the damping member may be a first frame, a first extension portion, and a first damping member, and the first stopper may include the first frame, the first extension portion, and the first damping member. 
     The second stopper may include a second frame mounted on the housing; a second extension portion extending from the second frame into the internal space of the housing to face a side of the second movable lens module in the optical axis direction; and a second damping member disposed on the second extension portion to face the side of the second movable lens module in the optical axis direction, and the first frame of the first stopper and the second frame of the second stopper may be integrally connected to each other. 
     The first stopper may be further configured to limit a movement of the first lens module in one direction in the optical axis direction, and the second stopper may be further configured to limit a movement of the second lens module in another direction in the optical axis direction opposite to the one direction in the optical axis direction. 
     The housing may include an insertion groove formed in an upper surface of a side wall of the housing, and the first frame may be inserted into the insertion groove. 
     The housing may include an insertion groove formed in an inner surface of a side wall of the housing; and the extension portion may be inserted into the insertion groove. 
     The stopper may further include a side wall mounting portion extending from the frame along an outer surface of a side wall of the housing. 
     The housing may include an insertion groove formed in the outer surface of the side wall of the housing, and the side wall mounting portion may be inserted into the insertion groove. 
     The camera module may further include a fixed lens module disposed at a fixed position in the internal space of the housing, the fixed lens module including at least one lens. 
     The camera module may further include three ball bearings disposed between a bottom surface of the housing and a lower surface of the fixed lens module. 
     The fixed lens module may be attached to the housing by an adhesive. 
     The lower surface of the fixed lens module or the bottom surface of the housing may include three guide grooves into which the three ball bearings are respectively partially inserted, and a position of the fixed lens module in the optical axis direction, a position of the fixed lens module in a first direction perpendicular to the optical axis direction, and a position of the fixed lens module in a second direction perpendicular to the optical axis direction and the first direction may be determined by the three guide grooves. 
     The three guide grooves may include a first guide groove having a shape of a triangular pyramid having its corners cut off, or a shape of a triangular pyramid having its corners cut off and having its tip cut off to form a flat bottom surface; a second guide groove extending in the optical axis direction and having a shape of a V, or a shape of a V having its tip cut off to form a flat bottom surface; and a third guide groove extending in the optical axis direction and having vertical sides and a flat bottom surface. 
     The first guide groove may contact a first one of the three ball bearings at three points, the second guide groove may contact a second one of the three ball bearings at two points, and the third guide groove may contact a third one of the three ball bearings at one point. 
     The three guide grooves may include a first guide groove extending in the optical axis direction and having a shape of a V, or a shape of a V having its tip cut off to form a flat bottom surface, the first guide groove further having side walls extending in the first direction, the side walls having protrusions extending in the second direction; a second guide groove extending in the optical axis direction and having a shape of a V, or a shape of a V having its tip cut off to form a flat bottom surface; and a third guide groove extending in the optical axis direction and having vertical sides and a flat bottom surface. 
     The first guide groove may contact a first one of the three ball bearings at four points, the second guide groove may contact a second one of the three ball bearings at two points, and the third guide groove may contact a third one of the three ball bearings at one point. 
     In another general aspect, a camera module includes a housing; a fixed lens module disposed at a fixed position in an internal space of the housing; and three ball bearings disposed between a lower surface of the fixed lens module and a bottom surface of the housing, wherein the lower surface of the fixed lens module or the bottom surface of the housing includes three guide grooves into which the three ball bearings are respectively partially inserted, and a position of the fixed lens module in an optical axis direction, a position of the fixed lens module in a first direction perpendicular to the optical axis direction, and a position of the fixed lens module in a second direction perpendicular to the optical axis direction and the first direction are determined by the three guide grooves. 
     The camera module may further include a plurality of movable lens modules disposed in the internal space of the housing and configured to be movable in the optical axis direction, each of the plurality of movable lens modules including at least one lens. 
     The plurality of movable lens modules may include a first movable lens module and a second movable lens module, the housing may include a first guide groove and a second guide groove both formed in a bottom surface of the housing and extending in the optical axis direction, and the camera module may further include three first ball bearings supporting a lower surface of the first movable lens module and including one first ball bearing disposed in the first guide groove and two second ball bearings disposed in the second guide groove; and three second ball bearings supporting a lower surface of the second movable lens module and including two second ball bearings disposed in the first guide groove and one second ball bearing disposed in the second guide groove. 
     The plurality of movable lens modules may include a first movable lens module and a second movable lens module, the housing may include a first guide groove, a second guide groove, a third guide groove, and a fourth guide groove all formed in a bottom surface of the housing, extending in the optical axis direction, and sequentially arranged in the first direction, and the camera module may further include three first ball bearings supporting a lower surface of the first movable lens module and including one first ball bearing disposed in the second guide groove and two first ball bearings disposed in the fourth guide groove; and three second ball bearings supporting a lower surface of the second movable lens module and including two second ball bearings disposed in the first guide groove and one second ball bearing disposed in the third guide groove. 
     In another general aspect, a camera module includes a housing; a first movable lens module disposed in an internal space of the housing and configured to be movable in an optical axis direction, the first movable lens module including at least one lens; a second movable lens module disposed in the internal space of the housing adjacent to the first movable lens module in the optical axis direction and configured to be movable in the optical axis direction, the second movable lens module including at least one lens; and a stopper mounted on an upper surface of the housing and extending into the internal space of the housing to prevent the first movable lens module and the second movable lens module from contacting one another as the first movable lens module and the second movable lens module move in the optical axis direction. 
     The stopper may include a frame mounted on the upper surface of the housing; a first extension portion extending from the frame into the internal space of the housing to face a surface of the first movable lens module; a first damping member disposed on the first extension portion to face the surface of the first movable lens module and contact the surface of the first movable lens module as the first movable lens module moves in one direction in the optical axis direction; a second extension portion extending from the frame into the internal space of the housing to face a surface of the second movable lens module; and a second damping member disposed on the second extension portion to face the surface of the second movable lens module and contact the surface of the second movable lens module as the second movable lens module moves in another direction in the optical axis direction opposite to the one direction. 
     The stopper may include a first frame mounted on the upper surface of the housing; a first extension portion extending from the first frame into the internal space of the housing to face a surface of the first movable lens module; a first damping member disposed on the first extension portion to face the surface of the first movable lens module and contact the surface of the first movable lens module as the first movable lens module moves in one direction in the optical axis direction; a second frame mounted on the upper surface of the housing; a second extension portion extending from the second frame into the internal space of the housing to face a surface of the second movable lens module; and a second damping member disposed on the second extension portion to face the surface of the second movable lens module and contact the surface of the second movable lens module as the second movable lens module moves in another direction in the optical axis direction opposite to the one direction. 
     The camera module may further include a fixed lens module disposed at a fixed position in the internal space of the housing adjacent to the second movable lens module in the optical axis direction so that the second movable lens module is disposed between the first movable lens module and the fixed lens module, the fixed lens module including at least one lens, wherein a lower surface of the fixed lens module may include three grooves, a bottom surface of the housing may include three grooves opposing the three grooves in the lower surface of the fixed lens module, the camera module may further include three ball bearings partially inserted into the three grooves in the lower surface of the fixed lens module and the three grooves in the bottom surface of the housing to support the fixed lens module in the housing, the grooves into which a first ball bearing of the three ball bearings is partially inserted may have a shape configured to constrain the fixed lens module in the optical axis direction, a first direction perpendicular to the optical axis direction, and a second direction perpendicular to the optical axis direction and the first direction, the grooves into which a second ball bearing of the three ball bearings is partially inserted may have a shape configured to constrain the fixed lens module in the first direction and the second direction, and the grooves into which a third ball bearing of the three ball bearings is partially inserted may have a shape configured to constrain the fixed lens module in the second direction. 
     In another general aspect, a camera module includes a housing; and a fixed lens module disposed at a fixed position in an internal space of the housing, the fixed lens module including at least one lens, wherein a lower surface of the fixed lens module includes three grooves, a bottom surface of the housing includes three grooves opposing the three grooves in the lower surface of the fixed lens module, the camera module further includes three ball bearings partially inserted into the three grooves in the lower surface of the fixed lens module and the three grooves in the bottom surface of the housing to support the fixed lens module in the housing, the grooves into which a first ball bearing of the three ball bearings is partially inserted have a shape configured to constrain the fixed lens module in an optical axis direction, a first direction perpendicular to the optical axis direction, and a second direction perpendicular to the optical axis direction and the first direction, the grooves into which a second ball bearing of the three ball bearings is partially inserted have a shape configured to constrain the fixed lens module in the first direction and the second direction, and the grooves into which a third ball bearing of the three ball bearings is partially inserted have a shape configured to constrain the fixed lens module in the second direction. 
     The three guide grooves in the lower surface of the fixed lens module and the three grooves in the bottom surface of the housing may each include a first guide groove having a shape of a triangular pyramid having its corners cut off, or a shape of a triangular pyramid having its corners cut off and having its tip cut off to form a flat bottom surface; a second guide groove extending in the optical axis direction and having a shape of a V, or a shape of a V having its tip cut off to form a flat bottom surface; and a third guide groove extending in the optical axis direction and having vertical sides and a flat bottom surface. 
     The three guide grooves in the lower surface of the fixed lens module and the three grooves in the bottom surface of the housing may each include a first guide groove extending in the optical axis direction and having a shape of a V, or a shape of a V having its tip cut off to form a flat bottom surface, the first guide groove further having side walls extending in the first direction, the side walls having protrusions extending in the second direction; a second guide groove extending in the optical axis direction and having a shape of a V, or a shape of a V having its tip cut off to form a flat bottom surface; and a third guide groove extending in the optical axis direction and having vertical sides and a flat bottom surface. 
     The camera module may further include a first movable lens module disposed in the internal space of the housing and configured to be movable in the optical axis direction, the first movable lens module including at least one lens; a second movable lens module disposed in the internal space of the housing between the first movable lens module and the fixed lens module in the optical axis direction and configured to be movable in the optical axis direction, the second movable lens module including at least one lens; and a stopper mounted on an upper surface of the housing and extending into the internal space of the housing to prevent the first movable lens module and the second movable lens module from contacting one another as the first movable lens module and the second movable lens module move in the optical axis direction. 
     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 of an example of a portable electronic device. 
         FIG.  2    is a perspective view of an example of a camera module. 
         FIGS.  3 A and  3 B  are cross-sectional views of an example of a camera module taken along the lines IIIA-IIIA′ and IIIB-IIIB′ in  FIG.  2   . 
         FIG.  4    is an exploded perspective view of an example of a camera module. 
         FIG.  5    is a perspective view of an example of a housing of a camera module. 
         FIG.  6 A  is a perspective view of an example of a reflection module and a lens module coupled to a housing of a camera module. 
         FIG.  6 B  is a perspective view of another example of a reflection module and a lens module coupled to a housing of a camera module. 
         FIG.  7    is a perspective view of an example of a board having driving coils and sensors mounted thereon coupled to a housing of a camera module. 
         FIG.  8 A  is an exploded perspective view of an example of a rotation plate and a rotating holder of a camera module. 
         FIG.  8 B  is an exploded perspective view of another example of a rotation plate and a rotating holder of a camera module. 
         FIG.  9 A  is an exploded perspective view of an example of a housing, a rotation plate, and a rotating holder of a camera module. 
         FIG.  9 B  is an exploded perspective view of another example of a housing, a rotation plate, and a rotating holder of a camera module. 
         FIG.  10    is an exploded perspective view of an example of a housing, a reflection module, and three lens barrels of a camera module. 
         FIG.  11 A  is a perspective view of an example of a damper of a rotating holder and a stopper of a zoom lens of a camera module. 
         FIG.  11 B  is a perspective view of another example of a stopper of a zoom lens of a camera module. 
         FIG.  12 A  is a exploded perspective view of the damper of the rotating holder and the stopper of the zoom lens of a camera module of  FIG.  11 A . 
         FIG.  12 B  is a exploded perspective view of the stopper of the zoom lens of a camera module of  FIG.  11 B . 
         FIG.  13 A  is a perspective view of another example of a housing of a camera module including separate guide grooves for a first lens barrel and a second lens barrel of a zoom lens of the camera module. 
         FIG.  13 B  is a bottom plan view of a first lens barrel and a second lens barrel of a zoom lens mounted in the separate guide grooves of the housing of a camera module of FIG. 
         FIG.  14    is a cross-sectional view of another example of a camera module taken along the line XIV-XIV′ in  FIG.  2    in which a third lens barrel of a zoom lens is fixed at a predetermined position. 
         FIGS.  15  and  16    are exploded perspective views of examples of a housing and a third lens barrel of a zoom lens of a camera module in which the third lens barrel is accurately fixed at a predetermined position. 
         FIG.  17    is a view of an example of a positional relationship between a magnet disposed on a first or second lens barrel of a zoom lens of a camera module and four Hall sensors of a position sensor opposing the magnet. 
         FIG.  18    is a graph of an example of output signals of the four Hall sensors with respect to a position of the magnet in the optical axis direction for the positional relationship illustrated in  FIG.  17   . 
         FIG.  19    is a view of another example of a positional relationship between a magnet disposed on a first or second lens barrel of a zoom lens of a camera module and four Hall sensors of a position sensor opposing the magnet. 
         FIG.  20    is a graph of an example of output signals of the four Hall sensors with respect to a position of the magnet in the optical axis direction for the positional relationship illustrated in  FIG.  19   . 
         FIG.  21    is a perspective view of an example of a main board having coils and components mounted thereon. 
         FIG.  22    is a perspective view of another example of a portable electronic device. 
     
    
    
     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. 
     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 shown 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 by 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. 
     The features of the examples described herein may be combined in various ways as will be apparent after 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 of an example of a portable electronic device. 
     Referring to  FIG.  1   , a portable electronic device  1  may be a portable electronic device  1 , such as a mobile communications terminal, a smartphone, or a tablet personal computer (PC), in which a camera module  1000  is mounted. 
     The portable electronic device  1  may be provided with the camera module  1000  to capture an image of a subject. 
     In this example, the camera module  1000  may include a plurality of lenses, and an optical axis (a Z-axis) of the lenses may be oriented in a direction perpendicular to a thickness direction (a Y-axis direction, or a direction from a front surface of the portable electronic device  1  to a rear surface thereof, or an opposite direction from the rear surface of the portable electronic device  1  to the front surface thereof) of the portable electronic device  1 . 
     In this example, the optical axis (the Z-axis) of the plurality of the lenses disposed in the camera module  1000  may be oriented in a width direction (a Z-axis direction) or a length direction (an X-axis direction) of the portable electronic device  1 . 
     Therefore, even when the camera module  1000  has the AF, zoom, and OIS functions, a thickness of the portable electronic device  1  may not increase. Therefore, the portable electronic device  1  may be made thinner. 
     The camera module  1000  may have the AF, zoom, and OIS functions. 
     The camera module  1000  having the AF, zoom, and OIS functions requires various components, leading to an increased size of the camera module  1000  compared to a conventional camera module. 
     The increased size of the camera module  1000  may make it difficult to miniaturize the portable electronic device  1  in which the camera module  1000  is mounted. 
     For example, a number of stacked lenses in the camera module may be increased to implement the zoom function. When multiple lenses are stacked in the thickness direction of the portable electronic device  1 , the thickness of the portable electronic device  1  may increase, depending on the number of the stacked lenses. Therefore, a sufficient number of the stacked lenses may not be provided without increasing the thickness of the portable electronic device  1 , thereby deteriorating the zoom function. 
     Furthermore, to implement the AF, zoom, and OIS functions, an actuator moving a plurality of lens groups in the optical axis direction or a direction perpendicular to the optical axis direction. When the optical axis (the Z-axis) of the lens groups is oriented in the thickness direction of the portable electronic device  1 , the actuator for moving the lens groups should also be installed in the thickness direction. Therefore, the thickness of the portable electronic device  1  may increase. 
     If the optical axis (the Z-axis) of the plurality of lenses is oriented to be perpendicular to the thickness direction of the portable electronic device  1 , the portable electronic device  1  may be made thinner even when the camera module  1000  having the AF, zoom, and OIS functions is mounted in the portable electronic device  2 . 
       FIG.  2    is a perspective view of an example of a camera module,  FIGS.  3 A and  3 B  are cross-sectional views of an example of a camera module taken along the lines IIIA-IIIA′ and IIIB-IIIB′ in  FIG.  2   , and  FIG.  4    is an exploded perspective view of an example of a camera module. 
     Referring to  FIGS.  2  to  4   , the camera module  1000  may include a reflection module  1100 , a lens module  1200 , and an image sensor module  1300  disposed in a housing  1010 . 
     The reflection module  1100  may be configured to change a propagation direction of light. As an example, a propagation direction of light incident through an opening portion  1031  of a cover  1030  covering an upper portion of the camera module  1000  may be changed to a direction toward the lens module  1200  through the reflection module  1100 . To this end, the reflection module  1100  may include a reflective member  1110  configured to reflect the light. 
     For example, a path of light incident in the thickness direction (the Y-axis direction) of the camera module  1000  may be changed by the reflection module  1100  so that the propagation direction of the incident light may be approximately the same as the optical axis (the Z-axis) direction. 
     The lens module  1200  may include a plurality of lenses through which passes the light having the propagation direction changed by the reflection module  1100 . The lens module  1200  may include at least three lens barrels  1210 ,  1220 , and  1230 . The three lens barrels  1210 ,  1220 , and  1230  are sometimes referred to in this application as a first lens barrel  1210 , a second lens barrel  1220 , and a third lens barrel  1230 . The AF and zoom functions may be implemented according to the movements of the at least three lens barrels  1210 ,  1220 , and  1230  in the optical axis (the Z-axis) direction. In addition, in this example, any one lens barrel, for example, the lens barrel  1230 , of the at least three lens barrels  1210 ,  1220 , and  1230  may be fixed so that it cannot move in the optical axis direction. The AF and zoom functions may be implemented by the fixed lens barrel  1230  and the remaining two lens barrels  1210  and  1220 . 
     The image sensor module  1300  may include an image sensor  1310  for converting the light that has passed through the plurality of lenses into an electrical signal, and a printed circuit board  1320  on which the image sensor  1310  may be mounted. Furthermore, the image sensor module  1300  may include an optical filter  1340  filtering the light that has passed through the lens module  1200 . The optical filter  1340  may be an infrared cut-off filter. 
     In an internal space of the housing  1010 , the reflection module  1100  may be disposed in front of the lens module  1200 , and the image sensor module  1300  may be disposed behind the lens module  1200 . 
     Referring to  FIGS.  2  to  21   , the camera module  1000  may include the reflection module  1100 , the lens module  1200 , and the image sensor module  1300 , which may be disposed in the housing  1010 . 
     The reflection module  1100 , the lens module  1200 , and the image sensor module  1300  may be sequentially disposed from a front end of the housing  1010  toward a rear end of the housing  1010 . The housing  1010  may have an internal space that is large enough so that all of the reflection module  1100 , the lens module  1200 , and the image sensor module  1300  may be disposed in the internal space of the housing  1010 . The printed circuit board  1320  included in the image sensor module  1300  may be attached to an outside of the housing  1010 . 
     For example, as illustrated in the drawings, the housing  1010  may be a single housing so that the reflection module  1100  and the lens module  1200  may be disposed in the internal space of the housing  1010 . However, the configuration of the housing  1010  is not limited thereto. For example, separate housings in which the reflection module  1100  and the lens module  1200  are respectively disposed may be connected to each other. 
     The housing  1010  may be covered with the cover  1030  so that the internal space of the housing  1010  is not exposed. 
     The cover  1030  may include the opening portion  1031  so that light is incident therethrough, and the propagation direction of the light incident through the opening portion  1031  may be changed by the reflection module  1100 , causing the light to be incident on the lens module  1200 . The cover  1030  may be a single cover covering the entire housing  1010 , or may be divided into separate covers respectively covering the reflection module  1100  and the lens module  1200 . 
     The reflection module  1100  may include the reflective member  1110  reflecting light. Furthermore, the light incident on the lens module  1200  may pass through the plurality of lens groups (the at least three lens barrels  1210 ,  1220 , and  1230 ), and may be then converted into an electrical signal by the image sensor  1310  and stored in a memory (not shown). 
     The housing  1010  may include the reflection module  1100  and the lens module  1200  disposed in the internal space of the housing  1010 . The reflection module  1100  may be disposed at the front end of the internal space of the housing  1010 , and the lens module  1200  may be disposed at the rear end of the internal space of the housing  1010 . In addition, spaces in which the lens barrels  1210 ,  1220 , and  1230  of the lens module  1200  may be provided may be separated from each other by protruding walls  1009 . The protruding walls  1009  may be protrude from both side walls of the housing  1010  into the internal space of the housing  1010 . 
     The reflection module  1100  disposed at the front end of the internal space of the housing  1010  may include a rotating holder  1120  closely adhered to and supported on an inner surface of a front wall of the housing  1010  by an attractive force between a pulling yoke  1153  disposed on the inner surface of the front wall of the housing  1010  and a pulling magnet  1151  disposed on the rotating holder  1120 . Alternatively, although not illustrated in the drawings, a pulling magnet may be disposed on the inner surface of the front wall of the housing  1010 , and a pulling yoke may be disposed on the rotating holder  1120 . Hereinafter, the structure illustrated in the drawings will be described for convenience of explanation. 
     First ball bearings  1131 , a rotation plate  1130 , and second ball bearings  1133  may be disposed between the inner surface of the front wall of the housing  1010  and the rotating holder  1120 . 
     As will be described in detail below, the first ball bearings  1131  and the second ball bearings  1133  may be partially inserted into guide grooves  1021 ,  1132 ,  1121 , and  1134 . A small space may be needed between the rotating holder  1120  and the third lens barrel  1230  to enable the rotating holder  1120  and the rotation plate  1130  to be disposed in the internal space of the housing  1010 . When the rotating holder  1120  is mounted on the housing  1010 , the rotating holder  1120  may be closely adhered to the inner surface of the front wall of the housing  1010  by the attractive force between the pulling yoke  1153  and the pulling magnet  1151 , thereby maintaining a small space between the rotating holder  1120  and the third lens barrel  1230 . 
     In this example, a damper  1050  may be mounted on an upper portion of the housing  1010  to support the rotating holder  1120 . Alternatively, without the damper  1050 , the attractive force between the pulling magnet  1151  and the pulling yoke  1153  may support the rotating holder  1120 . 
     The damper  1050  may include a frame  1051  mounted on upper surfaces of side walls of the housing  1010  and an upper surface of a front wall of the housing  1010 , locking portions  1055  extending downwardly perpendicular to the optical axis direction from a front end of the frame  1051 , extension portions  1052  extending downwardly perpendicular to the optical axis direction from rear ends of the frame  1051 , and damping members  1053  disposed on the extension portions  1052  and protruding toward and away from the rotating holder  1120  in the optical axis direction. The damping members  1053  may be inserted into through-holes formed in the extension portions  1052 . The damping members  1053  may be made of any elastic material, such as urethane, silicone, epoxy, or a polymer material. 
     The locking portions  1055  may be clipped onto the front wall of the housing  1010  to lock the damper  1050  to the housing  1010 . The housing  1010  may be provided with insertion grooves  1019  into which the frame  1051  the extension portions  1052 , and the locking portions  1055  are inserted. The insertion grooves  1019  may include first insertion grooves  1019   a  extending in the optical axis direction along inner edges of upper surfaces of side walls of the housing and formed in inner portions of the upper surfaces of the side walls of the housing  1010  and in an upper surface of a front wall of the housing  1010 , second insertion grooves  1019   b  extending downwardly perpendicular to the optical axis direction from rear ends of the first insertion groove  1019   a  and formed in inner surfaces of the side walls of the housing  1010 , and third insertion grooves  1019   c  extending downwardly perpendicular to the optical axis direction from front ends of the first insertion grooves  1019   a  and formed in an outer surface of the front wall of the housing  1010 . 
     The frame  1051  may be inserted into the first insertion grooves  1019   a , the locking portions  1055  provided at one end of the frame  1051  may be inserted into the third insertion grooves  1019   c  along the outside of the housing  1010 , and the extension portions  1052  provided at the other end of the frame  1051  may be inserted into the second insertion grooves  1019   b , the frame  1051  may be firmly fixed so that it cannot move in the optical axis direction. In addition, an adhesive may be applied between the frame  1051  and the housing  1010  to bond the frame  1051  and the housing  1010  to each other. 
     The damping members  1053  may be inserted into through-holes formed in the extension portions  1052 . Alternatively, the damping members  1053  may be attached to both sides of the extension portions  1052  by an adhesive. The damping members  1053  may protrude from both sides of the extension portions  1052  in the optical axis direction. The damping members  1053  may serve as a damper for absorbing the shock of the rotating holder  1120  or a stopper for limiting the moving distance of the rotating holder  1120 , and the third lens barrel  1230  may be fixed ( FIG.  6 B ). In this case, the third lens barrel  1230  may serve to support one side of the damping members  1053  in the optical axis direction. 
     The damper  1050  may serve as brackets supporting the rotating holder  1120  when the reflection module  1100  is not being driven, and may serve as a damper or a stopper controlling movement of the rotating holder  1120  when the reflection module  1100  is being driven. A space may be provided between the damper  1050  and the rotating holder  1120  to allow the rotating holder  1120  to rotate smoothly. Alternatively, even when the damper  1050  is in contact with the rotating holder  1120 , the damping members  1053  may be made of an elastic material to allow the rotating holder  1120  to move smoothly while being supported by the damper  1050 . 
     The housing  1010  may include a first driving portion  1140  and a second driving portion  1240  provided for respectively driving the reflection module  1100  and the lens module  1200 . The first driving portion  1140  may include a plurality of coils  1141   b ,  1143   b , and  1145   b  for driving the reflection module  1100 , and the second driving portion  1240  may include a plurality of coils  1241   b ,  1243   b , and  1245   b  for driving the lens module  1200 , where the lens module  1200  may include the first lens barrel  1210 , the second lens barrel  1220 , and the third lens barrel  1230 . 
     Furthermore, since the plurality of coils  1141   b ,  1143   b ,  1145   b ,  1241   b ,  1243   b , and  1245   b  may be provided in the housing  1010  in a state in which they are mounted on a main board  1070 , the housing  1010  may be provided with a plurality of through-holes  1010   a ,  1010   b ,  1010   c ,  1010   d ,  1010   e ,  1010   f , and  1010   g  so that the plurality of coils  1141   b ,  1143   b ,  1145   b ,  1241   b ,  1243   b , and  1245   b  may be exposed to the internal space of the housing  1010 . 
     The main board  1070  on which the coils  1141   b ,  1143   b ,  1145   b ,  1241   b ,  1243   b , and  1245   b  may be mounted may be provided as a single board as illustrated in the drawings. In this case, a single terminal portion may be provided, thereby making it easy to connect the main board  1070  to an external power supply and external signal lines. However, the main board  1070  is not limited to such a configuration, and may also be provided as a plurality of boards by separating a board on which the coils  1141   b ,  1143   b , and  1145   b  for driving the reflection module  1100  are mounted from a board on which the coils  1241   b ,  1243   b , and  1245   b  for driving the lens module  1200  are mounted. 
     The reflection module  1100  may change a path of light incident through the opening portion  1031 . When a still image or a moving image is captured, the still image may be blurred or the moving image may be shaken due to a hand-shake or other movement of a user. In this case, the reflection module  1100  may stabilize the hand-shake or other movement of the user by moving the rotating holder  1120  on which the reflective member  1110  is mounted. For example, when shaking is generated at the time of capturing a still image or a moving image due to a hand-shake or other movement of a user, the rotating holder  1120  may be moved by a relative displacement corresponding to the shaking to compensate for the shaking. 
     The OIS function may be implemented by a movement of the rotating holder  1120  having a relatively low weight since it does not include lenses or coils, and thus power consumption for the OIS function may be significantly reduced. 
     For example, for the OIS function implementation, the propagation direction of the light may be changed by moving the rotating holder  1120  on which the reflective member  1110  is provided without moving the lens barrels  1210 ,  1220 , and  1230  including a plurality of lenses of the lens module  1200  or the image sensor  1310  so that the light on which the OIS is performed may be incident to the lens module  1200 . 
     The reflection module  1100  may include the rotating holder  1120  supported by the housing  1010  via the rotation plate  1130 , the reflective member  1110  mounted on the rotating holder  1120 , and the first driving portion  1140  for moving the rotating holder  1120 . 
     The reflective member  1110  may change a propagation direction of light. For example, the reflective member  1110  may be a mirror or a prism reflecting the light. For convenience of illustration, the reflective member  1110  has been illustrated as a prism in the drawings. 
     The reflective member  1110  may be fixed to the rotating holder  1120 . The rotating holder  1120  has a mounting surface  1122  on which the reflective member  1110  is mounted. 
     The mounting surface  1122  of the rotating holder  1120  may be an inclined surface so that a path of light changes reflected by the reflective member  1110  mounted on the mounting surface  1122 . The mounting surface  1122  may be a surface inclined with respect to the optical axis (the Z-axis) of the plurality of the lenses by 30° to 60°. The inclined surface of the rotating holder  1120  may be directed toward the opening portion  1031  of the cover  1030  on which the light is incident. 
     The rotating holder  1120  on which the reflective member  1110  is mounted may be mounted to be movable in the internal space of the housing  1010 . For example, the rotating holder  1120  may be mounted in the housing  1010  to be rotatable around a first axis (the X-axis) and a second axis (the Y-axis). The first axis (the X-axis) and the second axis (the Y-axis) may be axes perpendicular to the optical axis (the Z-axis), and may be perpendicular to each other. 
     The rotating holder  1120  may be supported in the housing  1010  by the first ball bearings  1131  aligned along the first axis (the X-axis) and the second ball bearings  1133  aligned along the second axis (the Y-axis) so that the rotating holder  1120  rotates smoothly around the first axis (the X-axis) and the second axis (the Y-axis). As an example, two first ball bearings  1131  are aligned along the first axis (the X-axis) and two second ball bearings  1133  are aligned along the second axis (the Y-axis) as illustrated in the drawings. The rotating holder  1120  may be rotated around the first axis (the X-axis) and the second axis (the Y-axis) by the first driving portion  1140 , as described below. 
     Furthermore, the first ball bearings  1131  and the second ball bearings  1133  may be provided on a front surface and a rear surface of the rotation plate  1130 , respectively. Alternatively, the first ball bearings  1131  and the second ball bearings  1133  may be provided on a rear surface and a front surface of the rotation plate  1130 , respectively. That is, the first ball bearings  1131  may be aligned along the second axis (the Y-axis) and the second ball bearings  1133  may be aligned along the first axis (the X-axis). However, the structure illustrated in the drawings will hereinafter be described for convenience of explanation. The rotation plate  1130  may be provided between the rotating holder  1120  and the inner surface of the front wall of the housing  1010 . 
     The rotating holder  1120  may be supported in the housing  1010  via the first ball bearings  1131  provided between the housing  1010  and the rotation plate  1130 , the rotation plate  1130 , and the second ball bearings  1133  provided between the rotation plate  1130  and the rotating holder  1120  by the attractive force between the pulling magnet  1151  or the pulling yoke provided on the rotating holder  1120  and the pulling yoke  1153  or the pulling magnet provided on the housing  1010 . 
     The guide grooves  1132  and  1134  may be provided on the front surface and the rear surface of the rotation plate  1130  so that the first ball bearings  1131  and the second ball bearings  1133  may be inserted into the guide grooves  1132  and  1134 . The guide grooves  1132  and  1134  may include first guide grooves  1132  into which the first ball bearings  1131  are partially inserted, and second guide grooves  1134  into which the second ball bearings  1133  are partially inserted. 
     The housing  1010  may be provided with third guide grooves  1021  into which the first ball bearings  1131  are partially inserted, and the rotating holder  1120  may be provided with fourth guide grooves  1121  into which the second ball bearings  1133  are partially inserted. 
     The first guide grooves  1132 , the second guide grooves  1134 , the third guide grooves  1021 , and the fourth guide grooves  1121  described above may have a hemispherical or polygonal (polyprismatic or polypyramidal) groove shape so that the first ball bearings  1131  and the second ball bearings  1133  may easily rotate. 
     The first ball bearings  1131  and the second ball bearings  1133  may serve as bearings while rolling or sliding in the first guide grooves  1132 , the second guide grooves  1134 , the third guide grooves  1021 , and the fourth guide grooves  1121 . 
     Alternatively, as illustrated in  FIGS.  8 B and  9 B , the first guide grooves  1132  and the second guide grooves  1134  may be omitted from the front surface and the rear surface of the rotation plate  1130 , respectively, and first ball bearings  1131   a  and second ball bearings  1133   a  each having a hemispherical shape may be fixed to the front surface and the rear surface of the rotation plate  1130 , respectively. 
     However, the first ball bearings  1131   a  and the second ball bearings  1133   a  are not limited to the structure illustrated in  FIGS.  8 B and  9 B , but may have a structure in which they may be fixed to at least one of the housing  1010 , the rotation plate  1130 , and the rotating holder  1120 . For example, the first ball bearings  1131   a  may be fixed to the housing  1010  or to the front surface of the rotation plate  1130 , and the second ball bearings  1133   a  may be fixed to the rear surface of the rotation plate  1130  or to the rotating holder  1120 . In this case, only a member facing a member to which the first ball bearings  1131   a  or the second ball bearings  1133   a  are fixed may be provided with guide grooves, and the first ball bearings  1131   a  or the second ball bearings  1133   a  may serve as friction bearings by sliding rather than rotating. 
     Furthermore, the first ball bearings  1131   a  and the second ball bearings  1133   a  may be separately manufactured and then attached to any one of the housing  1010 , the rotation plate  1130 , and the rotating holder  1120 . Alternatively, the first ball bearings  1131   a  and the second ball bearings  1133   a  may be provided integrally with the housing  1010 , the rotation plate  1130 , or the rotating holder  1120  at the time of manufacturing the housing  1010 , the rotation plate  1130 , or the rotating holder  1120 . 
     The first driving portion  1140  generates a driving force capable of rotating the rotating holder  1120  around the first axis (the X-axis) and the second axis (the Y-axis). 
     As an example, the first driving portion  1140  may include a plurality of magnets  1141   a ,  1143   a , and  1145   a , and a plurality of coils  1141   b ,  1143   b , and  1145   b  arranged to face the plurality of magnets  1141   a ,  1143   a , and  1145   a , respectively. 
     When power is applied to the plurality of coils  1141   b ,  1143   b , and  1145   b , the rotating holder  1120  on which the magnets  1141   a ,  1143   a , and  1145   a  may be mounted may be rotated around the first axis (the X-axis) and the second axis (the Y-axis) by an electromagnetic interaction between the plurality of magnets  1141   a ,  1143   a , and  1145   a  and the plurality of coils  1141   b ,  1143   b , and  1145   b.    
     The plurality of magnets  1141   a ,  1143   a , and  1145   a  may be mounted on the rotating holder  1120 . As an example, the magnet  1141   a  may be mounted on a lower surface of the rotating holder  1120 , and the magnets  1143   a  and  1145   a  may be mounted on side surfaces of the rotating holder  1120 . 
     The plurality of coils  1141   b ,  1143   b , and  1145   b  may be mounted on the housing  1010 . As an example, the plurality of coils  1141   b ,  1143   b , and  1145   b  may be mounted on the housing  1010  through the main board  1070 . That is, the plurality of coils  1141   b ,  1143   b , and  1145   b  may be mounted on the main board  1070 , while the main board  1070  may be mounted on the housing  1010 . 
     In the drawings, an example in which the main board  1070  is a single board so that both the coils for the reflection module  1100  and the coils for the lens module  1200  may be mounted thereon is illustrated. However, the main board  1070  may be provided as at least two separate boards on which the coils for the reflection module  1100  and the coils for the lens module  1200  may be mounted, respectively. 
     A closed loop control method involving sensing a position of the rotating holder  1120  and providing feedback may be used when rotating the rotating holder  1120 . 
     Therefore, position sensors  1141   c  and  1143   c  may be provided for the closed loop control. The position sensors  1141   c  and  1143   c  may be Hall sensors. 
     The position sensors  1141   c  and  1143   c  may be disposed inside or outside the coils  1141   b  and  1143   b , respectively, and may be mounted on the main board  1070  on which the coils  1141   b  and  1143   b  are mounted. 
     The main board  1070  may be provided with a gyro sensor (not illustrated) sensing a shaking such as a hand-shake or other movement of the user, and may be provided with a driver integrated circuit (IC) (not illustrated) providing a driving signal to the plurality of coils  1141   b ,  1143   b , and  1145   b.    
     When the rotating holder  1120  rotates around the first axis (the X-axis), the rotation plate  1130  may rotate around the first ball bearings  1131  aligned along the first axis (the X-axis), which makes the rotating holder  1120  rotate as well. In this case, the rotating holder  1120  may not move relative to the rotation plate  1130 . 
     Furthermore, when the rotating holder  1120  rotates around the second axis (the Y-axis), the rotating holder  1120  rotates around the second ball bearings  1133  aligned along the second axis (the Y-axis) along the second axis (the Y-axis). In this case, the rotation plate  1130  may not rotate, and the rotating holder  1120  may thus rotate relative to the rotation plate  1130 . 
     For example, when the rotating holder  1120  rotates around the first axis (the X-axis), the first ball bearings  1131  may operate, and when the rotating holder  1120  rotates around the second axis (the Y-axis), the second ball bearings  1133  may operate. This is because, as illustrated in the drawings, the second ball bearings  1133  aligned along the second axis (the Y-axis) and inserted into the guide grooves  1134  cannot move when the rotating holder  1120  rotates around the first axis (the X-axis), and the first ball bearings  1131  aligned along the first axis (the X-axis) and inserted into the guide grooves  1132  cannot move when the rotating holder  1120  rotates around the second axis (the Y-axis). 
     The light reflected by the reflection module  1100  is incident on the lens module  1200 . Therefore, optical axes of the stacked lenses provided in the lens module  1200  may be aligned in the Z-axis direction, which is a direction in which the reflected light is emitted from the reflection module  1100 . 
     Referring to  FIG.  6 A , the two lens barrels  1210  and  1220  at the rear of the lens module  1200  may be responsible for the zoom function, and the lens barrel  1230  at the front of the lens module  1200  may be responsible for the AF function. Furthermore, the three lens barrels  1210 ,  1220 , and  1230  may perform the zoom and AF functions in various combinations. 
     Alternatively, referring to  FIG.  6 B , for example, the rear two lens barrels  1210  and  1220 , individually or in common, perform the zoom and AF functions, where, for example, the two lens barrels  1210  and  1220  combine to perform the zoom function, and the rearmost lens barrel  1210  may be further responsible for the AF function, and the front lens barrel  1230  may remain fixed to the housing  1010 . Furthermore, although not illustrated in the drawings, any one of the three lens barrels  1210 ,  1220 , and  1230  may remain fixed to the housing  1010  while the remaining two lens barrels may be responsible for the zoom and AF functions, individually or in common. In this case, the lens barrel (for example, lens barrel  1230 ) fixed to the housing  1010  does not require ball bearings or other bearings disposed between the fixed lens barrel and the housing  1010 . 
     In addition, the housing  1010  may be configured so that a space in which the one front lens barrel  1230  and the two rear lens barrels  1210  and  1220  may be partitioned by the protruding walls  1009 , but is not limited to such a configuration. The three lens barrels  1210 ,  1220 , and  1230  may be provided in a same space or in separate spaces. 
     The stacked lenses provided in the lens module  1200  may be divided into at least three lens barrels  1210 ,  1220 , and  1230 , respectively. Even when the stacked lenses are divided and provided in at least three lens barrels  1210 ,  1220 , and  1230 , the optical axes of the stacked lenses may be aligned in the Z-axis direction, which is a direction in which light may be emitted from the reflection module  1100 . 
     The lens module  1220  may include the second driving portion  1240  to implement the AF and zoom functions. 
     The lens modules  1220  may include at least three lens barrels, i.e., the first lens barrel  1210 , the second lens barrel  1220 , and the third lens barrel  1230 , disposed in the internal space of the housing  1010 , and may include the second driving portion  1240  moving the three lens barrels  1210 ,  1220 , and  1230  in the optical axis (the Z-axis) direction with respect to the housing  1010 . 
     The first to third lens barrels  1210 ,  1220 , and  1230  may be configured to move approximately in the optical axis (the Z-axis) direction for the AF and zoom functions. 
     In this regard, the second driving portion  1240  generates driving forces to move the first to third lens barrels  1210 ,  1220 , and  1230  in the optical axis (the Z-axis) direction. For example, the second driving portion  1240  enables the implementation of the AF and zoom functions by moving the first to third lens barrels  1210 ,  1220 , and  1230  individually in the optical axis (the Z-axis) direction. 
     The first to third lens modules  1210 ,  1220 , and  1230  may be configured to be supported on the bottom surface of the housing  1010 . For example, the first to third lens barrels  1210 ,  1220 , and  1230  may be individually supported by ball bearings on the bottom surface of the housing  1010 . Hereinafter, an example in which the first to third lens barrels  1210 ,  1220 , and  1230  may be individually supported by ball bearings on the bottom surface of the housing  1010  will be described. 
     As an example, the second driving portion  1240  may include a plurality of magnets  1241   a ,  1243   a , and  1245   a , and a plurality of coils  1241   b ,  1243   b , and  1245   b  disposed to face the magnets  1241   a ,  1243   a , and  1245   a , respectively. 
     When power is applied to the coils  1241   b ,  1243   b , and  1245   b , the first to third lens barrels  1210 ,  1220 , and  1230  on which the magnets  1241   a ,  1243   a , and  1245   a  may be separately mounted may be moved in the optical axis (the Z-axis) direction by an electromagnetic interaction between the magnets  1241   a ,  1243   a , and  1245   a  and the coils  1241   b ,  1243   b , and  1245   b.    
     The plurality of magnets  1241   a ,  1243   a , and  1245   a  may be separately mounted on the first to third lens barrels  1210 ,  1220 , and  1230 . As an example, the first magnet  1241   a  may be mounted on a side surface of the first lens barrel  1210 , the second magnet  1243   a  may be mounted on a side surface of the second lens barrel  1220 , and the third magnet  1245   a  may be mounted on a side surface of the third lens barrel  1230 . 
     The plurality of coils  1241   b ,  1243   b , and  1245   b  may be mounted on side walls of the housing  1010  to face the plurality of magnets  1241   a ,  1243   a , and  1245   a , respectively. The plurality of magnets  1241   a ,  1243   a , and  1245   a  may be provided on both side surfaces of the first to third lens barrels  1210 ,  1220 , and  1230 , and the plurality of coils  1241   b ,  1243   b , and  1245   b  may be provided on both side walls of the housing  1010  to face each other. 
     As an example, the main board  1070  may be mounted on the housing  1010 , while having the plurality of coils  1241   b ,  1243   b , and  1245   b  mounted thereon. 
     A closed loop control method involving sensing positions of the first to third lens barrels  1210 ,  1220 , and  1230  and providing feedback may be used when moving the first to third lens barrels  1210 ,  1220 , and  1230 . Therefore, position sensors  1241   c ,  1243   c , and  1245   c  may be provided for the closed loop control. The position sensors  1241   c ,  1243   c , and  1245   c  may be Hall sensors. 
     The position sensors  1241   c ,  1243   c , and  1245   c  may be disposed inside or outside of the coils  1241   b ,  1243   b , and  1245   b , respectively, and may be mounted on the main board  1070  on which each of the coils  1241   b ,  1243   b , and  1245   b  may be mounted. 
     In the drawings, the first lens barrel  1210  and the second lens barrel  1220  each may be driven by a coil and a magnet. In this case, a and a magnet may be provided on only one side of each of the first lens barrel  1210  and the second lens barrel  1220 . The coil and the magnet may have somewhat increased sizes to enhance the driving force. In such a case, a plurality of position sensors  1241   c  and  1243   c  may be provided for accurate position sensing. In the drawings, four position sensors  1241   c  and  1243   c  may be provided inside each of the coils  1241   b  and  1243   b  driving the first lens barrel  1210  and the second lens barrel  1220 . This is because the first lens barrel  1210  and the second lens barrel  1220  may be moved a considerable distance in the optical axis (the Z-axis) direction to implement a zoom function, so that a sufficient number of Hall sensors to sense the correct position should be provided. 
     The first lens barrel  1210  may be disposed in the housing  1010  to be movable in the optical axis (the Z-axis) direction. 
     A plurality of third ball bearings  1215  may be disposed between the first lens barrel  1210  and the bottom surface of the housing  1010 , and the first lens barrel  1210  may move with respect to the housing  1010  on the third ball bearings  1215 . 
     The plurality of third ball bearings  1215  serve as bearings guiding movement of the first lens barrel  1210  in a process of implementing the AF and zoom functions. 
     The plurality of third ball bearings  1215  may be configured to roll or slide in the optical axis (the Z-axis) direction when a driving force moving the first lens barrel  1210  in the optical axis (the Z-axis) direction is generated. Therefore, the plurality of third ball bearings  1215  guide the movement of the first lens barrel  1210  in the optical axis (the Z-axis) direction. 
     A plurality of guide grooves  1214  and  1013  accommodating the third ball bearings  1215  therein may be formed in a lower surface of the first lens barrel  1210  and the bottom surface of the housing  1010 , respectively, and the guide grooves  1013  may be elongated in the optical axis (the Z-axis) direction. 
     The plurality of third ball bearings  1215  may be accommodated in the guide grooves  2014  and  1013 , and may be inserted between the first lens barrel  1210  and the housing  1010 . 
     The guide grooves  2014  may be elongated in the optical axis (the Z-axis) direction. Furthermore, cross sections of the guide grooves  2014  and  1013  may have any of various shapes, such as a rounded shape or a polygonal shape. 
     The first lens barrel  1210  may be pressed toward the bottom surface of the housing  1010  so that the plurality of third ball bearings  1215  may remain in contact with the first lens barrel  1210  and the housing  1010 . To this end, a pulling yoke  1016  may be mounted on the bottom surface of the housing  1010  to face a pulling magnet  1216  mounted on the lower surface of the first lens barrel  1210 . The pulling yoke  1016  may be made of a magnetic material. Alternatively, a pulling magnet may be mounted on a bottom surface of the housing  1010 , and a pulling yoke may be mounted on a lower surface of the first lens barrel  1210 . 
     The coil  1241   b  driving the first lens barrel  1210  may be provided on one side surface of the housing  1010 . In this case, the electromagnetic force acts on one side surface of the first lens barrel  1210 , and thus the pulling magnet  1216  and the pulling yoke  1016  may be biased toward the one side surface of the housing  1010  from the center of the housing  1010  to facilitate the driving of the first lens barrel  1210 . The first lens barrel  1210  may be provided with an extension portion  1219  extending in the optical axis direction to oppose a side surface of the second lens barrel  1220  to increase the size of the magnet  1241   a  to enhance the driving force. Furthermore, to increase the size of the magnet  1243   a  for enhanced driving force, the second lens barrel  1220  may be provided with an extension portion  1229  extending in the optical axis direction to oppose a side surface of the first lens barrel  1210 . 
     The coil  1243   b  driving the second lens barrel  1220  may be provided on the other side surface of the housing  1010 , which may be an opposite side surface of the housing  1010  relative to the one side surface of the housing  1010  on which the coil  1241   b  may be provided. In this case, the electromagnetic force acts on the other side surface of the second lens barrel  1220 , a pulling magnet  1226  mounted on the lower surface of the second lens barrel  1220  and a pulling yoke  1017  mounted on the bottom surface of the housing  1010  may be biased toward the other side surface of the housing  1010  from the center of the housing  1010  to facilitate the driving of the second lens barrel  1220 . 
     Furthermore, the coil  1245   b  driving the third lens barrel  1230  may be provided on both side surfaces or one side surface of the housing  1010 . When the coil  1245   b  is provided on only one side surface of the housing  1010 , a pulling magnet  1236  mounted on the lower surface of the third lens barrel  1230  and a pulling yoke  1018  mounted on the bottom surface of the housing  1010  may be biased toward one side surface of the housing  1010  from the center of the housing  1010  to facilitate the driving of the third lens barrel  1230 , similarly to the first and second lens barrels  1210  and  1220 . However, this is only applicable to a case in which the coils  1241   b ,  1243   b , and  1245   b  driving the lens barrels  1210 ,  1220 , and  1230  may be provided on only one of the one side surface of the housing  101  and the other side surface of the housing  1010 . When the coils  1241   b ,  1243   b , and  1245   b  are provided on both side surfaces of the housing  1010 , the pulling magnets  1216 ,  1226 , and  1236  may be mounted approximately in the center of the lower surfaces of the lens barrels  1210 ,  1220 , and  1230 , and the pulling yokes  1016 ,  1017 , and  1018  may be mounted approximately in the center of the bottom surface of the housing  1010 . 
     The second lens barrel  1220  may be disposed in the housing  1010  to be movable in the optical axis (the Z-axis) direction. As an example, the second lens barrel  1220  may be disposed in series with the first lens barrel  1210  in the optical axis direction in front of the first lens barrel  1210 . 
     A plurality of fourth ball bearings  1225  may be disposed between the second lens barrel  1220  and the bottom surface of the housing  1010 , and the second lens barrel  1220  may move with respect to the housing  1010  on the fourth ball bearings  1225 . 
     The plurality of fourth ball bearings  1225  serve as bearings guiding movement of the second lens barrel  1220  in a process of implementing the AF and zoom functions. 
     The plurality of fourth ball bearings  1225  may be configured to roll or slide in the optical axis direction (the Z-axis direction) when a driving force moving the second lens barrel  1220  in the optical axis (the Z-axis) direction is generated. Therefore, the plurality of fourth ball bearings  1225  guide the movement of the second lens barrel  1220  in the optical axis (the Z-axis) direction. 
     A plurality of guide grooves  1224  and  1014  accommodating the fourth ball bearings  1225  therein may be formed in a lower surface of the second lens barrel  1220  and the bottom surface of the housing  1010 , respectively, and the guide grooves  1014  may be elongated in the optical axis (the Z-axis) direction. 
     The plurality of fourth ball bearings  1225  may be accommodated in the guide grooves  1224  and  1014 , and may be inserted between the second lens barrel  1220  and the housing  1010 . 
     Each of the plurality of guide grooves  1014  may be elongated in the optical axis (the Z-axis) direction. Furthermore, cross sections of the guide grooves  1224  and  1014  have any of various shapes, such as a rounded shape or a polygonal shape. 
     The second lens barrel  1220  may be pressed toward the bottom surface of the housing  1010  so that the fourth ball bearings  1225  may remain in contact with the second lens barrel  1220  and the housing  1010 . 
     To this end, the pulling yoke  1017  may be mounted on the bottom surface of the housing  1010  to face the pulling magnet  1226  mounted on the lower surface of the second lens barrel  1220 . The pulling yoke  1017  may be made of a magnetic material. Alternatively, a pulling magnet may be mounted on the bottom surface of the housing  1010 , and a pulling yoke may be mounted on the lower surface of the second lens barrel  1220 . 
     The third lens barrel  1230  may be disposed in the housing  1010  to be movable in the optical axis (the Z-axis) direction. As an example, the third lens barrel  1230  may be disposed in series with the second lens barrel  1220  in the optical axis direction in front of the second lens barrel  1220 . 
     A plurality of fifth ball bearings  1235  may be disposed between the third lens barrel  1230  and the bottom surface of the housing  1010 , and the third lens barrel  1230  may move with respect to the housing  1010  on the fifth ball bearings  1235 . 
     The plurality of fifth ball bearings  1235  serve as bearings guiding movement of the third lens barrel  1230  in a process of implementing the AF and zoom functions. 
     The plurality of fifth ball bearings  1235  may be configured to roll or slide in the optical axis direction (the Z-axis direction) when a driving force moving the third lens barrel  1230  in the optical axis (the Z-axis) direction is generated. Therefore, the plurality of fifth ball bearings  1235  guide the movement of the third lens barrel  1230  in the optical axis (the Z-axis) direction. 
     A plurality of guide grooves  1234  and  1015  accommodating the fifth ball bearings  1235  therein may be formed in a lower surface of the third lens barrel  1230  and the bottom surface of the housing  1010 , respectively, and the guide grooves  1015  may be elongated in the optical axis (the Z-axis) direction. 
     The plurality of fifth ball bearings  1235  may be accommodated in the guide grooves  1234  and  1015 , and may be inserted between the third lens barrel  1230  and the housing  1010 . 
     Each of the plurality of guide grooves  1015  may be elongated in the optical axis (the Z-axis) direction. Furthermore, cross sections of the guide grooves  1234  and  1015  may have various shapes, such as a rounded shape or a polygonal shape. 
     The third lens barrel  1230  may be pressed toward the bottom surface of the housing  1010  so that the fifth ball bearings  1235  may remain in contact with the third lens barrel  1230  and the housing  1010 . 
     To this end, the pulling yoke  1018  may be mounted on the bottom surface of the housing  1010  to face the pulling magnet  1236  mounted on the lower surface of the third lens barrel  1230 . The pulling yoke  1018  may be made of a magnetic material. Alternatively, a pulling magnet may be mounted on the bottom surface of the housing  1010 , and a pulling yoke may be mounted on the lower surface of the third lens barrel  1230 . 
     Guide grooves  1013 ,  1014 , and  1015  provided in the housing  1010  to guide the movements of the third to fifth ball bearings  1215 ,  1225 , and  1235  each may have an elongated groove shape extending in the optical axis direction, or at least two of the guide grooves  1013 ,  1014 , and  1015  may be connected to each other to form a single guide groove. In the case of the single guide groove in which at least two of the guide grooves  1013 ,  1014 , and  1015  are connected to each other, at least two of the first to third lens barrels  1210 ,  1220 , and  1230  may be easily aligned with each other in the optical axis direction. 
     An example in which the guide groves  1013  and  1014  provided to form moving paths of the first and second lens barrels  1210  and  1220  are connected to each other to form a single guide groove and the guide groove  1015  provided to form a moving path of the third lens barrel is provided separately is illustrated in the drawings. Alternatively, all of the guide grooves  1013 ,  1014 , and  1015  may be connected to each other to form a single groove. 
     In addition, at least some of the guide grooves  1214 ,  1224 , and  1234  of the first to third lens barrels  1210 ,  1220 , and  1230  may protrude from the lower surfaces of the first to third lens barrels  1214 ,  1224 , and  1234  toward the bottom surface of the housing  1010  on both sides of the optical axis to form anti-separation protrusions  1213 ,  1223 , and  1233  to prevent separation of the ball bearings  1215 ,  1225 , and  1235 . The anti-separation protrusions  1213 ,  1223 , and  1233  may have shapes corresponding to the shapes of the guide grooves  1013 ,  1014 , and  1015  formed in the bottom surface of the housing  1010 . The anti-separation protrusions  1213 ,  1223 , and  1233  have a height that is large enough so that they protrude into the guide grooves  1013 ,  1014 , and  1015 , but small enough that they do not contact the bottom surfaces of the guide grooves  1013 ,  1014 , and  1015  as the first to third lens barrels  1210 ,  1220 , and  1230  move in the optical axis direction. 
     However, the anti-separation protrusions  1213 ,  1223 , and  1233  are not limited to being provided on the lower surfaces of the first to third lens barrels  1210 ,  1220 , and  1230 , but instead may be provided on the bottom surface of the housing  1010  based on the same principle. 
     Furthermore, referring to  FIG.  13 A , the housing  1010  in another example may include separate guide grooves  1013   a ,  1013   b ,  1014   a , and  1014   b  for guiding movements of the first and second lens barrels  1210  and  1220  in the optical axis direction. For example, the housing  1010  may include a total of four separate first guide grooves  1013   a  and  1013   b  and second guide grooves  1014   a  and  1014   b , and the first lens barrel  1210  may be supported by the third ball bearings  1215  inserted into the first guide grooves  1013   a  and  1013   b , and the second lens barrel  1220  may be supported by the fourth ball bearings  1225  inserted into the second guide grooves  1014   a  and  1014   b.    
     In this case, since the first lens barrel  1210  and the second lens barrel  1220  are staggered with respect to each other in a direction perpendicular to the optical axis direction, the extension portions  1219  and  1229  of the first and second lens barrels  1210  and  1220  may move a greater distance in the optical axis direction without interference from the first and second lens barrels  1210  and  1220 . Therefore, the zoom performance may be further improved. 
     The first to third lens barrels  1210 ,  1220 , and  1230  in this example may be sequentially provided in the optical axis direction, and the first and second lens barrels  1210  and  1220  may be respectively provided with magnets  1241   a  and  1243   a  on one side thereof facing coils  1241   b  and  1243   b  mounted on the housing  1010 . In addition, the third lens barrel  1230  may be provided with a magnet  1245   a  on one side thereof facing a coil  1245   b  mounted on the housing  1010 . The magnets  1241   a ,  1243   a , and  1245   a  provided on the first to third lens barrels  1210 ,  1220 , and  1230  may be alternately arranged on one side of the first to third lens barrels  1210 ,  1220 , and  1230  and the other side of the first to third lens barrels  1210 ,  1220 , and  1230  in a zigzag manner to minimize mutual electromagnetic effects. 
     Since the first and second lens barrels  1210  and  1220  in this example are moved in the optical axis direction for performing the zoom and AF functions in one space partitioned by the protruding walls  1009 , they may come into contact with each other. In this case, it is not possible to accurately control the positions of the first and second lens barrels in the optical axis direction. 
     Therefore, in this example, a stopper  1060  may be provided to limit the movements of the first and second lens barrels  1210  and  1220 . The stopper  1060  may include a first stopper  1061  limiting a moving distance of the first lens barrel  1210 , and a second stopper  1062  limiting a moving distance of the second lens barrel  1220 . The first stopper  1061  and the second stopper  1062  may be provided separately (see  FIGS.  11 B and  12 B ), or may be interconnected (see  FIGS.  11 A and  12 A ). 
     The stopper  1060  may include the first stopper  1061  and the second stopper  1062 . In addition, a first frame  1061   a  and a second frame  1062   a  to be described below may be integrally connected (see  FIGS.  11 A and  12 A ), or may be separately provided (see  FIGS.  11 B and  12 B ). 
     First, a case in which the first frame  1061   a  and the second frame  1062   a  are integrally connected to each other will be described with reference to  FIGS.  11 A and  12 A . 
     When the first frame and the second frame are integrally connected to each other, the first frame  1061   a  and the second frame  1062   a  may include a third damping member  1061   d  and a fourth damping member  1062   d  facing the first and second lens barrels  1210  and  1220  to absorb impacts of the first and second lens barrels  1210  and  1220  moving upwardly. 
     The first stopper  1061  may include a first frame  1061   a , a first extension portion  1061   b  extending downwardly perpendicular to the optical axis direction from a front end of the first frame  1061   a , and a first damping member  1061   c  disposed on the first extension portion  1061   b.    
     The first damping member  1061   c  may be inserted into a through-hole formed in the first extension portion  1061   b  to protrude from both sides of the first extension portion  1061   b  in the optical axis direction, or may be attached to both sides of the first extension portion  1061   b  by an adhesive. 
     In addition, the first frame  1061   a  may be mounted on the upper surface of the left side wall of the housing  1010  and the upper surface of the rear wall of the housing  1010  to cover the portion of the first lens barrel  1210  in which the first extension portion  1219  is provided. The first extension portion  1061   b  and the first damping member  1061   c  may be inserted between the front side of the first lens barrel  1210  and the rear surface of the left protruding wall  1009 . 
     The housing  1010  may be provided with insertion grooves  1011  into which the first frame  1061   a  and the first extension portion  1061   b  are inserted. The insertion grooves  1011  may include a first insertion groove  1011   a  extending in the optical axis direction along an inner edge of the upper surface of the left side wall of the housing  1010  and formed in an inner portion of the upper surface of the left side wall of the housing  1010  and in an inner portion of the upper surface of the rear wall of the housing  1010 , and a second insertion groove  1011   b  extending downwardly perpendicular to the optical axis direction from a front end of the first insertion groove  1011   a  and formed in the inner surface of the left side wall of the housing  1010 . 
     The first frame  1061   a  may be inserted into the first insertion groove  1011   a , and the first extension portion  1061   b  may be inserted into the second insertion groove  1011   b . The first frame  1061   a  may be further attached to the housing  1010  by an adhesive. 
     To provide a space for accommodating the first extension portion  1061   b  and the first damping member  1061   c , a second space portion  1221  may be provided in the upper portion of the second lens barrel  1220 . 
     Therefore, the first lens barrel  1210  may be controlled to move only between the inner surface of the rear wall of the housing  1010  and the rear surface of the first damping member  1061   c  disposed behind the rear surface of the left protruding wall  1009 . 
     The second stopper  1062  may include a second frame  1062   a , a second extension portion  1062   b  extending downwardly perpendicular to the optical axis direction from the rear end of the second frame  1062   a , and a second damping member  1062   c  disposed on the second extension portion  1062   b.    
     The second damping member  1062   c  may be inserted into a through-hole formed in the second extension portion  1062   b  to protrude from both sides of the second extension portion  1062   b  in the optical axis direction, or may be attached to both sides of the second extension portion  1062   b  by an adhesive. 
     In addition, the second frame  1062   a  may be mounted on the upper surface of the right side wall of the housing  1010  and the upper surface of the right protruding wall  1009  to cover the portion of the second lens barrel  1220  in which the second extension portion  1229  is provided. The second extension portion  1062   b  and the second damping member  1062   c  may be inserted between rear side of the second lens barrel  1220  and the inner surface of the rear wall of the housing  1010 . 
     The housing  1010  may be provided with an insertion grooves  1012  into which the second frame  1062   a  and the second extension portion  1062   b  are inserted. The insertion grooves  1012  may include a first insertion groove  1012   a  extending in the optical axis direction along an inner edge of the upper surface of the right side wall of the housing  1010  and formed in an inner portion of the upper surface of the right side wall of the housing  1010  and in the upper surface of the right protruding wall  1009 , and a second insertion groove  1012   b  extending downwardly perpendicular to the optical axis direction from the rear end of the first insertion groove  1012   a  and formed in the inner surface of the right side wall of the housing  1010 . 
     The second frame  1062   a  may be inserted into the second insertion groove  1012   a , and the second extension portion  1062   b  may be inserted into the second insertion groove  1012   b . The second frame  1062   a  may be further attached to the housing  1010  by an adhesive. 
     To provide a space for accommodating the second extension portion  1062   b  and the second damping member  1062   c , a first space portion  1211  may be provided in the upper portion of the first lens barrel  1210 . 
     Therefore, the second lens barrel  1220  may be controlled to move only between the rear surface of the right protruding wall  1009  and the front surface of the second damping member  1062   c  disposed in front of the inner surface of the rear wall of the housing  1010 . 
     Next, a case in which the first frame  1061   a  and the second frame  1062   a  are provided separately from each other will be described with reference to  FIGS.  11 B and  12 B . 
     When the first frame and the second frame are provided separately, the first stopper  1061  may include a first frame  1061   a , a first extension portion  1061   b  extending downwardly perpendicular to the optical axis direction from a rear end of the frame  1061   a , and a first damping member  1061   c  disposed on the first extension portion  1061   b . In addition, the first stopper  1061  may include a first side wall mounting portion  1061   e  extending downwardly perpendicular to the optical axis direction from a left side of the first frame  1061   a , and a first protruding wall mounting portion  1061   f  extending downwardly perpendicular to the optical axis direction from a front end of the first frame  1061   a.    
     The first damping member  1061   c  may be inserted into a through-hole formed in the first extension portion  1061   b  to protrude from both sides of the first extension portion  1061   b  in the optical axis direction, or may be attached to both sides of the first extension portion  1061   b  by an adhesive. 
     In addition, the first frame  1061   a  may be mounted on the upper surface of the left side wall of the housing  1010  and the upper surface of the left protruding wall  1009  to cover a portion of the second lens barrel  1220  in which a second space portion  1221  is provided as will be described below. The first extension portion  1061   b  and the first damping member  1061   c  may be inserted between the front side of the first lens barrel  1210  and the rear surface of the left protruding wall  1009 . The first side wall mounting portion  1061   e  extending from the left side of the first frame  1061   a  may be clipped onto the left side wall of the housing  1010 , and the first protruding wall mounting portion  1061   f  extending from the front end of the first frame  1061   a  may be clipped onto the protruding wall  1009 , to improve a bonding force between the first stopper  1061  and the housing  1010 . 
     The housing  1010  may be provided with an insertion grooves  1011  into which the first frame  1061   a , the first side wall mounting portion  1061   e , and the first protruding wall mounting portion  1061   f  are inserted. The insertion grooves  1011  may include a first insertion groove  1011   a  extending in the optical axis direction along an inner edge of the upper surface of the left side wall of the housing  1010  and formed in an inner portion of the upper surface of the left side wall of the housing  1010 , a second insertion groove  1011   b  extending downwardly perpendicular to the optical axis direction from a left side of the first insertion groove  1011   a  and formed in an outer surface of the left side wall of the housing  1010 , and a third insertion groove  1011   c  extending downwardly perpendicular to the optical axis direction and formed in a portion of the front surface of the left protruding wall  1009  adjacent to the inner surface of the left side wall of the housing  1010 . 
     The first frame  1061   a  may be inserted into the first insertion groove  1011   a , the first side wall mounting portion  1061   e  may be inserted into the second insertion groove  1011   b , and the first protruding wall mounting portion  1061   f  may be inserted into the third insertion groove  1011   c . The first frame  1061   a , the first side wall mounting portion  1061   e , and the first protruding wall mounting portion  1061   f  may be additionally attached to the housing  1010  by an adhesive. 
     To provide a space for accommodating the first extension portion  1061   b  and the first damping member  1061   c , a second space portion  1221  may be provided in the upper portion of the second lens barrel  1220 . 
     Therefore, the first lens barrel  1210  may be controlled to move only between the inner surface of the rear wall of the housing  1010  and the front surface of the first damping member  1061   c  disposed behind the rear surface of the left protruding wall  1009 . 
     The second stopper  1062  may include a second frame  1062   a , a second extension portion  1062   b  extending downwardly perpendicular to the optical axis direction from a front end of the second frame  1062   a , and a second damping member  1062   c  disposed on the second extension portion  1062   b . In addition, the second stopper  1062  may include a second side wall mounting portion  1062   e  extending downwardly perpendicular to the optical axis direction from a right side of the second frame  1062   a , and a second rear wall mounting portion  1062   f  extending downwardly perpendicular to the optical axis direction from a rear end of the second frame  1062   a.    
     The second damping member  1062   c  may be inserted into a through-hole formed in the second extension portion  1062   b  to protrude from both sides of the second extension portion  1062   b  in the optical axis direction, or may be attached to both sides of the second extension portion  1062   b  by an adhesive. 
     In addition, the second frame  1062   a  may be mounted on the upper surface of the right side wall of the housing  1010  and the upper surface of the rear wall of the housing  1010  to cover a portion of the first lens barrel  1210  in which a first space portion  1211  is provided as will be described below. The second extension portion  1062   b  and the second damping member  1062   c  may be inserted between the rear side of the second lens barrel  1220  and the inner surface of the rear wall of the housing  1010 . The second side wall mounting portion  1062   e  extending from the right side of the second frame  1062   a  may be clipped onto the right side wall of the housing  1010 , and the second rear wall mounting portion  1062   f  extending from the rear end of the second frame  1062   a  may be clipped onto the rear wall of the housing  1010 , to improve a bonding force between the second stopper  1062  and the housing  1010 . 
     The housing  1010  may be provided with insertion grooves  1012  into which the second frame  1062   a , the second side wall mounting portion  1062   e , and the second rear wall mounting portion  1062   f  are inserted. The insertion grooves  1012  may include a first insertion groove  1012   a  extending in the optical axis direction along an inner edge of the upper surface of the right side wall of the housing  1010  and formed in an inner portion of the upper surface of the right side wall of the housing  1010 , a second insertion groove  1012   b  extending downwardly perpendicular to the optical axis direction from a right side of the first insertion groove  1011   a  and formed in an outer surface of the right side wall of the housing  1010 , and a third insertion groove  1012   c  extending downwardly perpendicular to the optical axis direction and formed in the outer surface of the rear wall of the housing  1010 . 
     The second frame  1062   a  may be inserted into the first insertion groove  1012   a , the first side wall mounting portion  1062   e  may be inserted into the second insertion groove  1012   b , and the second rear wall mounting portion  1062   f  may be inserted into the third insertion groove  1012   c . The second frame  1062   a , the second side wall mounting portion  1062   e , and the second rear wall mounting portion  1062   f  may be additionally attached to the housing  1010  by an adhesive. 
     To provide a space for accommodating the second extension portion  1062   b  and the second damping member  1062   c , a first space portion  1211  may be provided in the upper portion of the first lens barrel  1210 . 
     Therefore, the second lens barrel  1220  may be controlled to move only between the rear surface of the right protruding wall  1009  and the front surface of the second damping member  1062   c  disposed in front of the inner surface of the rear wall of the housing  1010 . 
     Referring to  FIG.  14   , an example of a structure for fixing a position at which the third lens barrel  1230  of a zoom lens is disposed in the housing  1010  will be described. 
     The housing  1010  of a camera module in this example may be provided with the damper  1050  for supporting the rotating holder  1120 , and the damping members  1053  may be provided on the extension portions  1052  to protrude toward and away from the rotating holder  1120  in the optical axis direction. The protruding walls  1009  that protrude into the internal space of the housing  1010  and partition the internal space of the housing  1010  into a space in which the first and second lens barrels  1210  and  1220  are disposed and a space in which the third lens barrel  1230  is disposed may be provided. 
     The third lens barrel  1230  may be disposed in the housing  1010  so that the front surfaces of the protruding walls  1009  are used as assembly reference surfaces and the front side of the third lens barrel  1230  is supported by the damping members  1053 . Since the damping members  1053  are made of an elastic material, the third lens barrel  1230  may be disposed between the damping members  1053  and the protruding walls  1009  by slightly compressing the damping members  1053 . Alternatively, the third lens barrel  1230  may be disposed in the housing first, and then the damping members  1053  of the damper  1050  may be inserted to press the third lens barrel  1230  against the protruding walls  1009 . In addition, an adhesive may be injected between the third lens barrel  1230  and the side walls of the housing  1010  and/or the bottom surface of the housing  1010  to bond the third lens barrel  1230  and the housing  1010  to each other. 
     Referring to  FIGS.  15  and  16   , examples of a structure in which the third lens barrel  1230  of a zoom lens is accurately fixed at a predetermined position will be described. 
     In these examples, since the third lens barrel  1230  is fixed to the housing  1010 , bearings needed to enable the third lens barrel  1230  to move in the optical axis direction may be unnecessary in principle. These examples disclose structures in which the third lens barrel  1230  is accurately disposed at a predetermined position in the housing  1010  using ball members. After the third lens barrel  1230  is disposed in the housing  1010 , an adhesive may be injected between the third lens barrel  1230  and the side walls of the housing  1010  and/or the bottom surface of the housing  1010  to bond the third lens barrel  1230  and the housing  1010  to each other. 
     First, referring to  FIG.  15   , the third lens barrel  1230  may be mounted by disposing three ball members  1235  between a lower surface of the third lens barrel  1230  and a bottom surface of the housing  1010 . Three pairs of guide grooves  1234  and  1015  into which the three ball members  1235  are respectively partially inserted may be respectively provided in portions of the lower surface of the third lens barrel  1230  and the bottom surface of the housing  1010  that face each other, with one pair of guide grooves  1234  and  1015  being provided individually for each ball member  1235 . However, this is just an example, and four or more ball members  1235  and four or more pairs of guide grooves  1234  and  1015  may be provided. 
     Each of the guide grooves  1234  and  1015  in a first pair of the three pairs of guide grooves  1234  and  1015  have a first shape illustrated in the enlarged view {circle around ( 1 )} in  FIG.  15   . Each of the guide grooves  1234  and  1015  in a second pair of the three pairs of guide grooves  1234  and  1015  have a second shape illustrated in the enlarged view {circle around ( 2 )} in  FIG.  15   . Each of the guide grooves  1234  and  1015  in a third pair of the three pairs of guide grooves  1234  and  1015  have a third shape illustrated in the enlarged view {circle around ( 3 )} in  FIG.  15   . The second shape is different from the first shape, and the third shape is different from the first shape and the second shape. 
     The guide groove  1234  or  1015  in the enlarged view {circle around ( 1 )} in  FIG.  15    has a shape of a triangular pyramid having its corners cut off, or a shape of a triangular pyramid having its corners cut off and having its tip cut off to form a flat bottom surface, which allows the corresponding ball member  1235  to contact only the three surfaces of the guide groove  1234  or  1015  marked with a dot in the enlarged view {circle around ( 1 )} in  FIG.  15   , and constrains the third lens barrel  1230  in the optical axis (the Z-axis) direction, the X-axis direction perpendicular to the optical axis direction, and the Y-axis direction perpendicular to the optical axis direction and the X axis direction. 
     The guide groove  1234  or  1015  in the enlarged view {circle around ( 2 )} in  FIG.  15    extends in the optical axis direction and has a shape of a V, or a shape of a V having its tip cut off to form a flat bottom surface, which allows the corresponding ball member  1235  to contact only the two surfaces of the guide groove  1234  or  1015  marked with a dot in the enlarged view {circle around ( 2 )} in  FIG.  15   , and constrains the third lens barrel  1230  in the X-axis direction and the Y-axis direction. 
     The guide groove  1234  or  1015  in the enlarged view {circle around ( 3 )} in  FIG.  15    extends in the optical axis direction and has vertical sides and a flat bottom surface, which allows the corresponding ball member  1235  to contact only the one surface of the guide groove  1234  or  1015  marked with a dot in the enlarged view {circle around ( 3 )} in  FIG.  15   , and constrains the third lens barrel  1230  in the Y-axis direction. 
     Since the third lens barrel  1230  is constrained in the X-axis direction, the Y-axis direction, and the optical axis (the Z-axis) direction by the guide grooves  1234  and  1015  having the shapes illustrated in the enlarged views {circle around ( 1 )}, {circle around ( 2 )}, and {circle around ( 3 )} in  FIG.  15   , the third lens barrel  1230  may be accurately positioned in the housing  1010  simply by inserting the ball members  1235  into the guide grooves  1015  in the bottom surface of the housing  1010 , and then placing the third lens barrel  1230  into the housing  1010  so that the guide grooves  1234  in the lower surface of the housing  1010  fit over the ball members  1235  in the guide grooves  1015 . 
     Alternatively, referring to  FIG.  16   , the third lens barrel  1230  may be mounted by disposing three ball members  1235  between a lower surface of the third lens barrel  1230  and a bottom surface of the housing  1010 . Three pairs of guide grooves  1234  and  1015  into which the ball members  1235  are respectively partially inserted may be respectively provided in portions of the lower surface of the third lens barrel  1230  and the bottom surface of the housing  1010  that face each other, with one pair of guide grooves  1234  and  1015  being provided individually for each ball member  1235 . However, this is just an example, and four or more ball members  1235  and four or more pairs of guide grooves  1234  and  1015  may be provided. 
     A first guide groove of the guide grooves  1234  and  1015  in a first pair of the three pairs of guide grooves  1234  and  1015  has a first shape illustrated in the enlarged view {circle around ( 1 )} in  FIG.  16    in which side walls have protrusions. A second guide groove of the guide grooves  1234  and  1015  in the first pair of the three pairs of guide grooves  1234  and  1015  has a modified first shape similar to the first shape illustrated in the enlarged view {circle around ( 1 )} in  FIG.  16   , except that the side walls have recesses to receive the protrusions of the side walls of the first guide groove. Each of the guide grooves  1234  and  1015  in a second pair of the three pairs of guide grooves  1234  and  1015  have a second shape illustrated in the enlarged view {circle around ( 2 )} in  FIG.  16   . Each of the guide grooves  1234  and  1015  in a third pair of the three pairs of guide grooves  1234  and  1015  have a third shape illustrated in the enlarged view {circle around ( 3 )} in  FIG.  16   . The second shape is different from the first shape and the modified first shape, and the third shape is different from the first shape, the modified first shape, and the second shape. 
     A guide groove in the enlarged view {circle around ( 1 )} in  FIG.  16    is a first guide groove of the guide grooves  1234  and  1015  in the first pair of the three pairs of guide grooves  1234  and  1015 , and extends in the optical axis (the Z-axis) direction and has a shape of a V, or a shape of a V having its tip cut off to form a flat bottom surface, and further has side walls extending in the X-axis direction perpendicular to the optical axis direction, the side walls having protrusions extending in the Y-axis direction perpendicular to the optical axis direction and the X-axis direction, which allows the corresponding ball member  1235  to contact only the four surfaces of the first guide groove marked with a dot in the enlarged view {circle around ( 1 )} in  FIG.  16   , and constrains the third lens barrel  1230  in the optical axis direction, the X-axis direction, and the Y-axis direction. 
     A second guide groove of the guide grooves  1234  and  1015  in the first pair of the three pairs of guide grooves  1234  and  1015  has a shape similar to the shape of the first guide groove of the guide grooves  1234  and  1015  in the first pair of the three pairs of guide grooves  1234  and  1015  illustrated in the enlarged view {circle around ( 1 )} in  FIG.  16   , except that the side walls of the second guide groove have recesses to receive the protrusions of the side walls of the first guide groove illustrated in the enlarged view {circle around ( 1 )} in  FIG.  16   , which allows the corresponding ball member  1235  to contact only the two surfaces of the V of the second guide groove marked with a dot in the enlarged view {circle around ( 1 )} in  FIG.  16   . However, the third lens barrel  1230  is nevertheless constrained in the optical axis direction, the X-axis direction, and the Y-axis direction by the first guide groove as discussed above. 
     The guide groove  1234  or  1015  in the enlarged view {circle around ( 2 )} in  FIG.  16    extends in the optical axis direction and has a shape of a V, or a shape of a V having its tip cut off to form a flat bottom surface, which allows the corresponding ball member  1235  to contact only the two surfaces of the guide groove  1234  or  1015  marked with a dot in the enlarged view {circle around ( 2 )} in  FIG.  16   , and constrains the third lens barrel  1230  in the X-axis direction and the Y-axis direction. 
     The guide groove  1234  or  1015  in the enlarged view {circle around ( 3 )} in  FIG.  16    extends in the optical axis direction and has vertical sides and a flat bottom surface, which allows the corresponding ball member  1235  to contact only the one surface of the guide groove  1234  or  1015  marked with a dot in the enlarged view {circle around ( 3 )} in  FIG.  15   , and constrains the third lens barrel  1230  in the Y-axis direction. 
     Since the third lens barrel  1230  is constrained in the X-axis direction, the Y-axis direction, and the optical axis (the Z-axis) direction by the guide grooves  1234  and  1015  having the shapes illustrated in the enlarged views {circle around ( 1 )}, {circle around ( 2 )}, and {circle around ( 3 )} and the modified shape discussed above that is similar to the shape illustrated in the enlarged view {circle around ( 1 )}, the third lens barrel  1230  may be accurately positioned in the housing  1010  simply by inserting the ball members  1235  into the guide grooves  1015  in the bottom surface of the housing  1010 , and then placing the third lens barrel  1230  into the housing  1010  so that the guide grooves  1234  in the lower surface of the housing  1010  fit over the ball members  1235  in the guide grooves  1015 . 
       FIG.  17    is a view of an example of a positional relationship between a magnet disposed on a first or second lens barrel of a zoom lens of a camera module and four Hall sensors of a position sensor opposing the magnet, and  FIG.  18    is a graph of an example of output signals of the four Hall sensors with respect to a position of the magnet in the optical axis direction for the positional relationship illustrated in  FIG.  17   . 
     Referring to  FIG.  17   , the first or second lens barrel  1210  or  1220  may move a considerable distance in the optical axis direction to perform a zoom or AF function, and a position of the first or second lens barrel  1210  or  1220  in the optical axis direction needs to be sensed by the Hall sensor  1241   c  or  1243   c  as accurately as possible. 
     Therefore, in this example, the position sensor  1241   c  or  1243   c  includes four Hall sensors Hall 1  to Hall 4  disposed to face the magnet  1241   a  or  1243   a  of the first or second lens barrel  1210  or  1220 . In this example, the magnet  1241   a  or  1243   a  may be magnetized to form a two-pole magnet having N and S poles (or alternatively S and N poles) in a moving direction (indicated by the arrow in  FIG.  17   ) of the first or second lens barrel  1210  or  1220  in the optical axis direction, and the magnet  1241   a  or  1243   a  may be disposed to oppose a coil  1241   b  or  1243   b . When the magnet  1241   a  or  1243   a  is centered with respect to the coil  1241   b  or  1243   b , two of the Hall sensors Hall 1  and Hall 2  oppose the N pole (or alternatively the S pole) of the magnet  1241   a  or  1243   a , and the remaining two Hall sensors Hall 3  and Hall 4  oppose the S pole (or alternatively the N pole) of the magnet  1241   a  or  1243   a . The four Hall sensors Hall 1  to Hall 4  may be arranged side by side inside the coil  1241   b  or  1243   b  in the moving direction of the magnet  1241   a  or  1243   a . In detail, the four Hall sensors Hall 1  to Hall 4  may be spaced apart from each other by the same distance, they may be disposed symmetrically about a neutral region (indicated by the white strip between the N and S poles) of the magnet  1241   a  or  1243   a.    
     Referring to  FIG.  18   , when the magnet  1241   a  or  1243   a  moves in a + or − direction in the optical axis direction, output signals of the four Hall sensors Hall 1  to Hall 4  vary in different ways with respect to a position of the magnet  1241   a  or  1243   a  in the optical axis direction, but a Hall signal calculated according to the equation Hall signal=Hall 1 +Hall 2 +Hall 3 +Hall 4  varies approximately linearly with respect to the position of the magnet  1241   a  or  1243   a  in the optical axis direction. 
     When the magnet  1241   a  or  1243   a  moves a relatively long distance in the optical axis direction, it may be difficult to accurately sense the position of the magnet  1241   a  or  1243   a  in the optical axis direction using only one or two Hall sensors. However, by using the four Hall sensors Hall 1  to Hall 4  as illustrated in  FIG.  17   , accurate position sensing is possible even when the magnet  1241   a  or  1243   a  moves a relatively long distance as illustrated in  FIG.  18   . 
       FIG.  19    is a view of another example of a positional relationship between a magnet disposed on a first or second lens barrel of a zoom lens of a camera module and four Hall sensors of a position sensor opposing the magnet, and  FIG.  20    is a graph of an example of output signals of the four Hall sensors with respect to a position of the magnet in the optical axis direction for the positional relationship illustrated in  FIG.  19   . 
     Referring to  FIG.  19   , the first or second lens barrel  1210  or  1220  may move a considerable distance in the optical axis direction to perform a zoom or AF function, and a position of the first or second lens barrel  1210  or  1220  in the optical axis direction needs to be sensed by the position sensor  1241   c  or  1243   c  as accurately as possible. 
     Therefore, in this example, the position sensor  1241   c  or  1243   c  includes four Hall sensors Hall 1  to Hall 4  disposed to face the magnet  1241   a  or  1243   a  of the first or second lens barrel  1210  and  1220 . In this example, the magnet  1241   a  or  1243   a  may be magnetized to form a three-pole magnet having N, S, and N poles (or alternatively S, N, and S poles) in a moving direction of the first or second lens barrel  1210  or  1220 , in the optical axis direction and the magnet  1241   a  or  1243   a  may be disposed to oppose a coil  1241   b  or  1243   b  provided as a set of two coils. When the magnet  1241   a  or  1243   a  is centered with respect to the coil  1241   b  or  1243   b , the two coils of the coil  1241   a  or  1243   a  are respectively centered with respect to the two N poles on opposite sides of the S pole (or alternatively with respect to the two S poles on opposite sides of the N pole). 
     When the magnet  1241   a  or  1243   a  is centered with respect to the coil  1241   b  or  1243   b , two of the Hall sensors Hall 1  and Hall 2  oppose the N pole (or alternatively the S pole) on the left side of the magnet  1241   a  or  1243   a  so that a left edge of the Hall sensor Hall 1  is aligned with a left edge of the N pole (or alternatively the S pole), and a right edge of the Hall sensor Hall 2  is aligned with a right edge of the N pole (or alternatively the S pole). The remaining two Hall sensors Hall 3  and Hall 4  oppose the N pole (or alternatively the S pole) on the right side of the magnet  1241   a  or  1243   a  so that a left edge of the Hall sensor Hall 3  is aligned with a left edge of the N pole (or alternatively the S pole), and a right edge of the Hall sensor Hall 4  is aligned with a right edge of the N pole (or alternatively the S pole). 
     Referring to  FIG.  20   , when the magnet  1241   a  or  1243   a  moves in a + or − direction in the optical axis direction, output signals of the four Hall sensors vary in different ways with respect to a position of the magnet  1241   a  or  1243   a  in the optical axis direction, but a Hall signal calculated according to the equation Hall signal=(Hall 1 +Hall 2 )−(Hall 3 +Hall 4 ) varies approximately linearly with respect to the position of the magnet  1241   a  or  1243   a  in the optical axis direction. 
     When the magnet  1241   a  or  1243   a  moves a relatively long distance in the optical axis direction, it may be difficult to accurately sense the position of the magnet  1241   a  or  1243   a  in the optical axis direction using only one or two Hall sensors. However, by using the four Hall sensors Hall 1  to Hall 4  as illustrated in  FIG.  19   , accurate position sensing is possible even when the magnet  1241   a  or  1243   a  moves a relatively long distance as illustrated in  FIG.  20   . 
       FIG.  21    is a perspective view of an example of a main board having coils and components mounted thereon. 
     Referring to  FIG.  21   , the coils  1141   b ,  1143   b , and  1145   b  and the position sensors  1141   c  and  1143   c  of the first driving portion  1140  for driving the reflection module  1100 , and the coils  1241   b ,  1243   b , and  1245   b  and the position sensors  1241   c ,  1243   c , and  1245   c  of the second driving portion  1240  for driving the lens module  1200 , may be mounted on an internal surface of a main board  1070 . Furthermore, components  1178 , such as passive elements and active elements, and a gyro sensor  1079  may be mounted on an external surface of the main board  1070 . Therefore, the main board  1070  may be a double-sided main board. 
     Specifically, the main board  1070  may include first and second side boards  1071  and  1072  disposed approximately parallel to each other, and a bottom board  1073  connecting the first and second side boards  1071  and  1072  to each other. A single terminal portion  1074  for connecting the camera module to an external power supply and external signal lines may be connected to any one of the first and second side boards  1071  and  1072  and the bottom board  1073 . 
     The coil  1143   b  and the position sensor  1143   c  of the first driving portion  1140  for driving the reflection module  1100 , and the coils  1241   b  and  1245   b  and the position sensors  1241   c  and  1245   c  of the second driving portion  1240  for driving the lens module  1200 , may be mounted on the first side board  1071 . 
     The coil  1145   b  of the first driving portion  1140  for driving the reflection module  1100 , and the coil  1243   b  and the position sensor  1243   c  of the second driving portion  1240  for driving the lens module  1200 , may be mounted on the second side board  1072 . 
     The coil  1141   b  and the position sensor  1141   c  of the first driving portion  1140  for driving the reflection module  1100  may be mounted on the bottom board  1073 . 
     Although the first side board  1071  is illustrated in the drawings as having components  1178 , such as passive elements and active elements, and the gyro sensor  1079  mounted thereon, the components  1178  and the gyro sensor  1079  may be mounted on the second side board  1072 , or may be suitably divided and mounted on the first and second side boards  1071  and  1072 . 
     Furthermore, the coils  1141   b ,  1143   b ,  1145   b ,  1241   b ,  1243   b , and  1245   b  and the position sensors  1141   c ,  1143   c ,  1241   c ,  1243   c , and  1245   c , which may be mounted on the first side board  1071 , the second side board  1072 , and the bottom board  1073  as illustrated in FIG.  21 , may be variously divided and mounted on the first side board  1071 , the second side board  1072 , and the bottom board  1073  according to the design of a camera module. 
       FIG.  22    is a perspective view of another example of a portable electronic device. 
     Referring to  FIG.  22   , a portable electronic device  2  may be a portable electronic device in which a plurality of camera modules  500  and  1000  are mounted, such as a mobile communications terminal, a smartphone, or a tablet PC. 
     The plurality of camera modules  500  and  1000  may be mounted in the portable electronic device  2 . 
     At least one of the plurality of camera modules  500  and  1000  may be the camera module  1000  described with reference to  FIGS.  2  through  21   . 
     For example, in the case of the portable electronic device  2  including two camera modules  500  and  1000 , at least one of two camera modules  500  and  1000  may be the camera module  1000 . 
     The examples described above enable the camera module and the portable electronic device including the camera module to have a simple structure, a reduced size, and a reduced power consumption while implementing the AF function, the zoom function, and the OIS function. 
     In addition, the examples described above enable easy alignment of a plurality of lens barrels of a lens module in an optical axis direction. 
     In addition, the examples described above include a stopper and a damper to prevent the lens barrels of a zoom lens and a reflection module from being displaced from optimal positions. 
     In addition, the examples described above enable the performance of a zoom lens to be maximized by accurately measuring positions of the lens barrels of the zoom lens in the optical axis direction using a position sensor including a plurality of Hall sensors. 
     While this disclosure includes specific examples, it will be apparent after an understanding of the disclosure of this application that various changes in forms 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.