Patent Publication Number: US-2022217278-A1

Title: Camera module and optical device

Description:
TECHNICAL FIELD 
     Embodiments relate to a camera module and an optical device including the same. 
     BACKGROUND ART 
     Voice coil motor (VCM) technology, which is used in conventional general camera modules, is difficult to apply to a micro-scale camera module, which is intended to exhibit low power consumption, and study related thereto has been actively conducted. 
     There is increasing demand for, and production of, electronic products such as smart phones and cellular phones equipped with cameras. Cameras for cellular phones have been increasing in resolution and decreasing in size, and accordingly, an actuator therefor is also becoming smaller, larger in diameter, and more multifunctional. In order to realize a high-resolution cellular phone camera, improvement in the performance of the cellular phone camera and additional functions, such as autofocusing, shutter shaking prevention, and zooming in and out, are required. 
     DISCLOSURE 
     Technical Problem 
     Embodiments provide a camera module and an optical device including the same capable of compensating for deviation of the optical center of a lens-moving unit due to gravity during hand-tremor compensation, thus preventing deterioration in resolution and improving the accuracy of hand-tremor compensation. 
     Technical Solution 
     A camera module according to an embodiment includes an image sensor, a moving unit including a lens, the moving unit being disposed on the image sensor, a fixing unit, an elastic member interconnecting the fixing unit and the moving unit, and a controller configured to, when the moving unit is tilted by gravity, acquire a correction value to compensate for the extent of tilting of the moving unit and to control movement of the moving unit using the correction value. 
     The camera module may include a motion sensor, and the controller may acquire posture information on the moving unit using sensing information of the motion sensor. 
     The posture information on the moving unit may include a tilt angle of a reference axis at the current position of the moving unit with respect to the reference axis at a reference position, and the reference position may be a position at which the reference axis, perpendicular to a sensor surface of the image sensor, is parallel to the direction of gravity. 
     The camera module may include a memory storing correction value information on the moving unit corresponding to the posture information on the moving unit, and the controller may acquire the correction value using the posture information on the moving unit and may compensate for the extent of tilting of the moving unit. 
     The correction value information on the moving unit stored in the memory may include at least one of the extent of tilting of the moving unit and variation in the position of an optical center of the moving unit. 
     The controller may control the moving unit to move in a direction perpendicular to an optical axis in order to perform hand-tremor compensation. 
     During the hand-tremor compensation, the correction value may be used to compensate for hand tremor. 
     The controller may compensate for the extent of tilting of the moving unit, and may perform the hand-tremor compensation. 
     In addition, in order to perform the hand-tremor compensation, the controller may calculate target position information on the moving unit using the correction value, may acquire current position information on the moving unit, may acquire error information for hand-tremor compensation based on the target position information and the current position information on the moving unit, and may control the moving unit to move in a direction perpendicular to the optical axis based on the error information. 
     The controller may receive acceleration information on the camera module, and may acquire the posture information on the moving unit using the received acceleration information on the camera module. 
     The controller may acquire the extent of tilting of the moving unit using Z-axis acceleration of the camera module. 
     The camera module may include an OIS position sensor disposed at the fixing unit and configured to output an output signal in response to the result of sensing the movement of the moving unit in a direction perpendicular to the optical axis to the controller, and the controller may acquire the current position information on the moving unit based on the output signal of the OIS position sensor. 
     The controller may include a look-up table storing correction value information corresponding to preset respective pieces of posture information on the moving unit, and the controller may acquire the correction value of the moving unit corresponding to the acquired posture information on the moving unit using the look-up table. 
     The correction value information may include a tilt angle of the moving unit. 
     The correction value information may include variation between the position of the optical center of the moving unit at the reference position and the position of the optical center of the moving unit at the current position. 
     The correction value information may include default variation, which is variation in the position of the optical center of the moving unit when the moving unit is tilted by a reference angle in the direction of gravity in the preset posture information. 
     The controller may include a correction value generator configured to generate the correction value using the acquired posture information on the moving unit, a target position calculator configured to calculate target position information on the moving unit based on the correction value, a position detector configured to detect position information on the moving unit, a driving signal generator configured to generate a driving control signal using the target position information on the moving unit and the position information on the moving unit, and a driver configured to control the movement of the moving unit in a direction perpendicular to the optical axis based on the driving control signal. 
     Advantageous Effects 
     Embodiments are capable of compensating for deviation of the optical center of a lens-moving unit due to gravity during hand-tremor compensation, thereby preventing deterioration in resolution and improving the accuracy of hand-tremor compensation. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  is an exploded perspective view of a camera module according to an embodiment. 
         FIG. 2  is a cross-sectional view of an embodiment of the lens-moving unit shown in  FIG. 1 . 
         FIG. 3  is a block diagram of a lens-moving unit, a motion sensor, and a controller of the camera module shown in  FIG. 1 . 
         FIG. 4  is a flowchart of a hand-tremor control method of a hand-tremor controller according to an embodiment. 
         FIG. 5  is a configuration diagram illustrating an embodiment of the hand-tremor controller. 
         FIG. 6A  illustrates an example of correction value information stored in a correction value generator. 
         FIG. 6B  illustrates another example of correction value information stored in the correction value generator. 
         FIG. 6C  illustrates still another example of correction value information stored in the correction value generator. 
         FIG. 7  is a flowchart illustrating a method of generating a correction value stored in the correction value generator. 
         FIG. 8  illustrates a method of acquiring variation in an optical center of a moving unit shown in  FIG. 7 . 
         FIG. 9  illustrates a posture difference of the moving unit and a coordinate value of the position CO of the optical center of the moving unit at a reference position. 
         FIG. 10  illustrates a posture difference of the moving unit and a coordinate value of the position of the optical center of the moving unit calculated based on preset posture information on the moving unit. 
         FIG. 11  illustrates an embodiment of a method of acquiring the correction value of the moving unit. 
         FIG. 12  is a diagram for explaining measurement of default variation in the position of the optical center of the moving unit according to  FIG. 11 . 
         FIG. 13  illustrates the state in which the posture difference of the moving unit is corrected by the hand-tremor controller. 
         FIG. 14  illustrates a hand-tremor controller according to another embodiment. 
         FIG. 15  is a perspective view of a portable terminal according to an embodiment. 
         FIG. 16  is a configuration diagram of the portable terminal shown in  FIG. 15 . 
     
    
    
     BEST MODE 
     Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. 
     The technical spirit of the disclosure is not limited to the embodiments to be described, and may be implemented in various other forms, and one or more of the components may be selectively combined and substituted for use without exceeding the scope of the technical spirit of the disclosure. 
     In addition, terms (including technical and scientific terms) used in the embodiments of the disclosure, unless specifically defined and described explicitly, are to be interpreted as having meanings that may be generally understood by those having ordinary skill in the art to which the disclosure pertains, and meanings of terms that are commonly used, such as terms defined in a dictionary, should be interpreted in consideration of the context of the relevant technology. 
     Further, the terms used in the embodiments of the disclosure are for explaining the embodiments and are not intended to limit the disclosure. In this specification, the singular forms may also include plural forms unless otherwise specifically stated in a phrase, and in the case in which “at least one (or one or more) of A, B, or C” is stated, it may include one or more of all possible combinations of A, B, and C. 
     In addition, in describing the components of the embodiments of the disclosure, terms such as “first”, “second”, “A”, “B”, “(a)”, and “(b)” can be used. Such terms are only for distinguishing one component from another component, and do not determine the nature, sequence, or procedure of the corresponding constituent elements. 
     In addition, when it is described that a component is “connected”, “coupled” or “joined” to another component, the description may include not only being directly “connected”, “coupled” or “joined” to the other component but also being “connected”, “coupled” or “joined” by another component between the component and the other component. In addition, in the case of being described as being formed or disposed “above (on)” or “below (under)” another component, the description includes not only the case where the two components are in direct contact with each other, but also the case where one or more other components are formed or disposed between the two components. In addition, when expressed as “above (on)” or “below (under)”, it may refer to a downward direction as well as an upward direction with respect to one element. 
     Hereinafter, a camera module and an optical device including the same according to embodiments will be described with reference to the accompanying drawings. For convenience of description, the camera module will be described using the Cartesian coordinate system (x,y,z), but the embodiments are not limited thereto, and may be described using other coordinate systems. In the respective drawings, the x-axis and the y-axis may be directions perpendicular to the z-axis, which is an optical-axis direction, the z-axis direction, which is the optical-axis direction, may be referred to as a “first direction”, the x-axis direction may be referred to as a “second direction”, and the y-axis direction may be referred to as a “third direction”. 
     The camera module according to the embodiment may perform an “autofocusing function”. Here, the autofocusing function is a function of automatically focusing an image of a subject on the surface of an image sensor. 
     In addition, the camera module according to the embodiment may perform a “hand-tremor compensation function”. Here, the hand-tremor compensation function is a function of inhibiting the contour of a captured still image from being blurred due to vibration caused by shaking of a hand of a user when capturing the still image. 
     Hereinafter, a lens-moving unit may be referred to as a lens-moving apparatus, a voice coil motor (VCM), or an actuator. Hereinafter, the term “coil” may be interchanged with “coil unit”, the term “elastic member” may be interchanged with “elastic unit” or “spring”, and the term “support member” may be interchanged with “wire” or “spring”. In addition, the term “terminal” may be interchanged with “pad”, “electrode”, “conductive layer”, or “bonding unit”. 
       FIG. 1  is an exploded perspective view of a camera module  200  according to an embodiment. 
     Referring to  FIG. 1 , the camera module  200  may include a lens module  400 , a lens-moving unit  100 , an adhesive member  612 , a filter  610 , a holder  600 , a circuit board  800 , an image sensor  810 , a motion sensor  820 , a controller  830 , and a connector  840 . 
     The lens module  400  may be mounted in a bobbin  110  of the lens-moving unit  100 . The lens module  400  may include a plurality of lenses. Alternatively, the lens module  400  may include a plurality of lenses and a lens barrel in which the lenses are mounted. 
     The holder  600  may be disposed under a base  210  of the lens-moving unit  100 . 
     The holder  600  may be referred to as a “sensor base”, and may be omitted in another embodiment. 
     The filter  610  may be mounted to the holder  600 , and the holder  600  may include a seating portion  500  on which the filter  610  is seated. For example, the seating portion  500  may have a structure protruding from the upper surface of the holder  600 , without being limited thereto. In another embodiment, the seating portion  500  may be formed in the shape of a recess that is depressed from the upper surface of the holder  600 . 
     The adhesive member  612  may couple or attach the base  210  of the lens-moving unit  100  to the holder  600 . The adhesive member  612  may serve not only to bond components, as described above, but also to prevent foreign substances from entering the lens-moving unit  100 . 
     For example, the adhesive member  612  may be an epoxy, a thermosetting adhesive, or an ultraviolet-curable adhesive. 
     The filter  610  may serve to block light in a specific frequency band, among the light passing through the lens module  400 , from entering the image sensor  810 . The filter  610  may be an infrared cut-off filter, without being limited thereto. In this case, the filter  610  may be disposed parallel to the x-y plane. 
     An opening may be formed in a portion of the holder  600 , to which the filter  610  is mounted, so as to allow light passing through the filter  610  to enter the image sensor  810 . 
     The circuit board  800  may be disposed under the holder  600 , and the image sensor  810  may be disposed on or mounted on the circuit board  800 . The image sensor  810  is a part on which the light that has passed through the filter  610  is incident and in which an image included in the light is formed. 
     The circuit board  800  may be provided with various circuits, elements, and controllers in order to convert an image formed by the image sensor  810  into an electrical signal and to transmit the electrical signal to an external device. 
     A circuit pattern and a plurality of terminals may be formed on the circuit board  800 . For example, the circuit board  800  may be implemented as a printed circuit board or a flexible printed circuit board, without being limited thereto. 
     The image sensor  810  may be electrically connected to the circuit board  800 , and may include an active area AR or an effective area, which receives an image included in the light incident thereon through the lens-moving unit  100  and converts the received image into an electrical signal. 
     The filter  610  and the image sensor  810  may be spaced apart from each other so as to be opposite each other in the first direction. 
     The motion sensor  820  may be disposed on or mounted on the circuit board  800 , and may be electrically connected to the controller  830  via the circuit pattern provided on the circuit board  800 . 
     The motion sensor  820  outputs rotating angular speed information and acceleration information according to the motion of the camera module  200 . 
     The motion sensor  820  may sense a change in the angular speed according to the motion of the camera module  200  and the position of the lens-moving unit  100 , which is moved in response to the motion of the camera module  200 . 
     The motion sensor  820  may include a 3-axis gyro sensor, an angular speed sensor, and/or an acceleration sensor, or may include an inertial measurement unit (IMU). 
     In another embodiment, the motion sensor  820  may be omitted from the camera module  200 , and may be mounted in an optical device. In still another embodiment, motion sensors may be mounted in both the camera module and the optical device. 
     The controller  830  is disposed on or mounted on the circuit board  800 . 
     The controller  830  may be electrically connected to the circuit board  800 , and the circuit board  800  may be electrically connected to a circuit board  250  of the lens-moving unit  100 . 
     The controller  830  may be electrically connected to a first coil  120  and a second coil of the lens-moving unit  100 . 
     In addition, the controller  830  may be electrically connected to an AF position sensor and an optical image stabilizer (OIS) position sensor. 
     The controller  830  may provide a driving signal to each of the first coil  120  and the second coil. In addition, the controller  830  may provide a driving signal to each of the AF position sensor and the OIS position sensor, and may receive output from each of the AF position sensor and the OIS position sensor. 
     For example, the controller  830  may control a driving signal for performing hand-tremor compensation on an OIS operation unit (or an OIS unit) of the lens-moving unit  100  based on the angular speed data provided from the motion sensor and the output signal provided from the OIS position sensor of the lens-moving unit  100 . 
     The connector  840  may be electrically connected to the circuit board  800 , and may include a port to be electrically connected to an external device. 
       FIG. 2  is a cross-sectional view of an embodiment of the lens-moving unit  100  shown in  FIG. 1 . 
     Referring to  FIG. 2 , the lens-moving unit  100  may move the lens module  400 . 
     The lens-moving unit  100  may include a bobbin  110 , a first coil  120 , a magnet  130 , a housing  140 , an upper elastic member  150 , a lower elastic member  160 , a support member  220 , a second coil, and optical image stabilization (OIS) position sensors  240   a  and  240   b.    
     In addition, the lens-moving unit  100  may further include a base  210 , a circuit board  250 , and a cover member  300 . 
     The bobbin  110  may be disposed inside the housing  140 , and may be moved in the direction of the optical axis OA or the first direction (e.g. the Z-axis direction) by the electromagnetic interaction between the first coil  120  and the magnet  130 . 
     The bobbin  110  may have an opening formed therein to allow the lens or the lens barrel to be mounted therein. 
     The bobbin  110  may include a first stopper protruding from the upper surface thereof. In addition, the bobbin  110  may include a second stopper protruding from the lower surface thereof. 
     The bobbin  110  may be provided at the upper portion or the upper surface thereof with a first coupling portion to allow the upper elastic member  150  to be coupled and secured thereto, and may be provided at the lower portion or the lower surface thereof with a second coupling portion to allow the lower elastic member  160  to be coupled and secured thereto. For example, each of the first and second coupling portions of the bobbin  110  may have the shape of a protrusion, a recess, or a plane. 
     In an example, the bobbin  110  may have a seating recess formed in the outer surface thereof to allow the first coil  120  to be seated, inserted, or disposed therein, without being limited thereto. 
     The first coil  120  is disposed at the bobbin  110 . In an example, the first coil  120  may be disposed on the outer surface of the bobbin  110 . 
     For example, the first coil  120  may have the shape of a closed loop, a coil block, or a coil ring so as to be disposed on the outer surface of the bobbin  110 . In an example, the first coil  120  may be implemented in the form of a coil ring that is wound around the outer surface of the bobbin  110  about the optical axis, without being limited thereto. In another embodiment, the first coil may be implemented in the form of a coil ring that is wound about a straight line perpendicular to the optical axis. 
     A driving signal may be provided to the first coil  120 . At this time, the provided driving signal may be a direct-current signal or an alternating-current signal, or may include a direct-current signal and an alternating-current signal, and may have the form of voltage or current. 
     When a driving signal (e.g. driving current) is supplied to the first coil  120 , electromagnetic force may be formed through the interaction between the first coil  120  and the magnet  130 , and an AF operation unit (e.g. the bobbin  110 ) may be moved in the first direction (e.g. the z-axis direction), or may be tilted by the formed electromagnetic force. 
     At the initial position of the AF operation unit, the AF operation unit (e.g. the bobbin  110 ) may be moved in an upward direction or a downward direction, which is referred to as bidirectional driving of the AF operation unit. Alternatively, at the initial position of the AF operation unit, the AF operation unit (e.g. the bobbin  110 ) may be moved in the upward direction, which is referred to as unidirectional driving of the AF operation unit. 
     For example, the AF operation unit may include the bobbin  110  and components coupled to the bobbin  110  (e.g. the first coil  120 ). 
     The initial position of the AF operation unit may be the original position of the AF operation unit in the state in which no power is applied to the first coil  120  or the position at which the AF operation unit is located as the result of the upper and lower elastic members  150  and  160  being elastically deformed due only to the weight of the AF operation unit. 
     In addition, the initial position of the bobbin  110  may be the position at which the AF operation unit is located when gravity acts in the direction from the bobbin  110  to the base  210  or when gravity acts in the direction from the base  210  to the bobbin  110 . 
     The housing  140  accommodates the bobbin  110  therein and supports the magnet  130 . 
     The housing  140  may generally have a hollow pillar shape. For example, the housing  140  may have a polygonal (e.g. quadrangular or octagonal) or circular opening formed therein to allow the bobbin  110  to be mounted or disposed therein, and the opening in the housing  140  may be a through-hole formed through the housing  140  in the optical-axis direction. 
     The housing  140  may include a plurality of side portions and a plurality of corners. 
     Each of the corners of the housing  140  may be disposed or located between two adjacent side portions, and may interconnect the side portions. 
     Each of the side portions of the housing  140  may be disposed parallel to a corresponding one of side plates of the cover member  300 . 
     In order to prevent the housing  140  from directly colliding with the inner surface of an upper plate of the cover member  300 , the housing  140  may be provided at the upper portion, the upper end, or the upper surface thereof with a first stopper. In addition, in order to prevent the lower surface of the housing  140  from colliding with the base  210  and/or the circuit board  250 , the housing  140  may be provided at the lower portion, the lower end, or the lower surface thereof with a second stopper. 
     The housing  140  may be provided at the upper portion, the upper end, or the upper surface thereof with at least one first coupling portion, which is coupled to a first outer frame of the upper elastic member  150 , and may be provided at the lower portion, the lower end, or the lower surface thereof with a second coupling portion, which is coupled and secured to a second outer frame of the lower elastic member  160 . 
     For example, each of the first coupling portion and the second coupling portion of the housing  140  may have the shape of a protrusion, a recess, or a plane. 
     The magnet  130  may be disposed at the housing  140 . 
     In an example, the magnet  130  may be disposed on at least one of the side portions of the housing  140 . Alternatively, in another embodiment, the magnet  130  may be disposed on at least one of the corners of the housing  140 . The housing  140  may be provided with a seating portion to allow the magnet  130  to be seated therein, and the seating portion may have the shape of an opening, a hole, or a recess. 
     For example, the magnet  130  may be a monopolar magnetized magnet or a bipolar magnetized magnet. 
     The lens-moving unit  100  according to the embodiment may further include a sensing magnet and an AF position sensor in order to implement a feedback AF operation. 
     In an example, the sensing magnet may be disposed at the bobbin  110 , and the AF position sensor may be disposed at the housing  140 . In addition, the lens-moving unit  100  may be disposed at the housing  140 , and may further include a circuit board on which the AF position sensor is disposed or mounted. In this case, the circuit board may include terminals that are electrically connected to the AF position sensor. 
     The sensing magnet may be moved together with the bobbin  110  in the optical-axis direction, and the AF position sensor may output a sensing signal (e.g. a sensing voltage) in response to the result of sensing the intensity of the magnetic field of the sensing magnet, which changes according to the movement of the bobbin  110 . 
     In another embodiment, the sensing magnet may be disposed at the housing  140 , and the AF position sensor may be disposed at the bobbin  110 . 
     The AF position sensor may be implemented as a Hall sensor alone, or may be implemented in the form of a driver integrated circuit (IC) that includes a Hall sensor and a driver. 
     The upper elastic member  150  may be coupled to the upper portion, the upper end, or the upper surface of the bobbin  110 , and the lower elastic member  160  may be coupled to the lower portion, the lower end, or the lower surface of the bobbin  110 . 
     In an example, the upper elastic member  150  may be coupled to the upper portion, the upper end, or the upper surface of the bobbin  110  and to the upper portion, the upper end, or the upper surface of the housing  140 , and the lower elastic member  160  may be coupled to the lower portion, the lower end, or the lower surface of the bobbin  110  and to the lower portion, the lower end, or the lower surface of the housing  140 . 
     The upper elastic member  150  and the lower elastic member  160  may elastically support the bobbin  110  with respect to the housing  140 . 
     The support member  220  may support the housing  140  to be movable relative to the base  210  and/or the circuit board  250  in a direction perpendicular to the optical axis, and may electrically connect at least one of the upper or lower elastic member  150  or  160  to the circuit board  250 . 
     The upper elastic member  150  may include a plurality of upper elastic units that are electrically separated from each other. The plurality of upper elastic units may be electrically connected to the terminals of the circuit board on which the AF position sensor is disposed. 
     The upper elastic member or at least one of the plurality of upper elastic units may include a first outer frame coupled to the housing  140 . For example, the upper elastic member may include a first inner frame coupled to the bobbin  110 , a first outer frame coupled to the housing  140 , and a first frame connection portion interconnecting the first inner frame and the first outer frame. 
     The support member  220  may include a plurality of support members, and each of the plurality of support members may electrically connect a corresponding one of the plurality of upper elastic units to a corresponding one of the terminals of the circuit board  250 . 
     The support members  220  may be disposed at the corners of the housing  140 . In an example, each of the support members  220  may be disposed at a corresponding one of the corners  142 - 1  to  142 - 4  of the housing  140 . In another embodiment, the support members may be disposed at the side portion of the housing  140 . 
     In an example, using solder or a conductive adhesive member, one end of the support member  220  may be coupled to the first outer frame of the upper elastic member or the upper elastic unit, and the other end of the support member  220  may be coupled to the circuit board  250 . 
     The support member  220  may be implemented as a member that is conductive and performs a support function using the elasticity thereof, for example, a suspension wire, a leaf spring, or a coil spring. Alternatively, in another embodiment, the support member  220  may be integrally formed with the upper elastic member  150 . 
     The lower elastic member  160  may include a plurality of lower elastic units. 
     The lower elastic member  160  or at least one of the lower elastic units may include a second inner frame, which is coupled or secured to the lower portion, the lower surface, or the lower end of the bobbin  110 , a second outer frame, which is coupled or secured to the lower portion, the lower surface, or the lower end of the housing  140 , and a second frame connection portion, which interconnects the second inner frame and the second outer frame. 
     The upper elastic member  150  (or the upper elastic unit) and the lower elastic member  160  (or the lower elastic unit) may be implemented as a leaf spring, without being limited thereto, and may alternatively be implemented as a coil spring or the like. The term “elastic unit” may be interchanged with “spring”, the term “outer frame” may be interchanged with “outer portion”, the term “inner frame” may be interchanged with “inner portion”, and the support member  220  may be referred to as a “wire”. 
     In an example, the first coil  120  may be directly connected or coupled to the second inner frames of any two of the lower elastic units. Alternatively, the first coil  120  may be directly connected or coupled to the first inner frames of any two of the upper elastic units. 
     The AF position sensor may be electrically connected to the circuit board  250  via the upper elastic units and the support members. When the AF position sensor is mounted on the circuit board disposed in the housing  140 , the upper elastic units may be electrically connected to the circuit board on which the AF position sensor is mounted. 
     The first coil  120  may be electrically connected to the circuit board  250  via two lower elastic units (or two upper elastic units) and the support members. 
     The base  210  may have therein an opening corresponding to the opening in the bobbin  110  and/or the opening in the housing  140 , and may have a shape that coincides with or corresponds to that of the cover member  300 , for example, a quadrangular shape. For example, the opening in the base  210  may be a through-hole formed through the base  210  in the optical-axis direction. 
     The base  210  may be provided at the upper surface thereof with a seating recess in which the OIS position sensor is disposed. The base  210  may be provided at the lower surface thereof with a seating portion in which the filter  610  of the camera module  200  is mounted. 
     The second coil may be disposed on the circuit board  250 , and the OIS position sensor may be disposed in the seating recess in the base  210 , which is located below the circuit board  250 . The first coil may be referred to as an “AF coil”, and the second coil may be referred to as an “OIS coil”. 
     The OIS position sensor may include a first sensor  240   a  and a second sensor  240   b  (refer to  FIG. 7 ). 
     The first and second sensors  240   a  and  240   b  may sense the displacement of an OIS operation unit in a direction perpendicular to the optical axis. Here, the OIS operation unit (or the OIS unit) may include the AF operation unit and components mounted to the housing  140  (e.g. the magnet  130  and the AF position sensor). 
     For example, the AF operation unit may include the bobbin  110  and components mounted to the bobbin  110  so as to move together with the bobbin  110 . For example, the AF operation unit may include the bobbin  110 , a lens (not shown) mounted to the bobbin  110 , the first coil  120 , and the sensing magnet. 
     The circuit board  250  may be disposed on the upper surface of the base  210 , and may have therein an opening corresponding to the opening in the bobbin  110 , the opening in the housing  140 , and/or the opening in the base  210 . The opening in the circuit board  250  may be a through-hole. 
     The circuit board  250  may have a shape that coincides with or corresponds to that of the upper surface of the base  210 , for example, a quadrangular shape. 
     The circuit board  250  may include a plurality of terminals for receiving electrical signals from the outside. 
     The second coil may be disposed under the bobbin  110 . For example, the second coil may include coil units  230 - 1  and  230 - 2 , which correspond to or face the magnet  130  disposed at the housing  140  in the optical-axis direction. 
     The coil units  230 - 1  and  230 - 2  of the second coil may be disposed above the circuit board  250  or on the upper surface of the circuit board  250 . 
     For example, the second coil may include a circuit member  231  and a plurality of coil units  230 - 1  and  230 - 1  formed at the circuit member  231 . Here, the circuit member  231  may be referred to as a “board”, a “circuit board”, or a “coil board”. 
     For example, the second coil may include two coil units  230 - 1  and  230 - 2 , which face each other in a first horizontal direction (or a first diagonal direction), and two coil units, which face each other in a second horizontal direction (or a second diagonal direction), without being limited thereto. 
     In an example, the two coil units  230 - 1  and  230 - 2  facing each other in the first horizontal direction (or the first diagonal direction) may be connected in series to each other, and the two coil units facing each other in the second horizontal direction (or the second diagonal direction) may be connected in series to each other, without being limited thereto. For example, the first horizontal direction (or the first diagonal direction) and the second horizontal direction (or the second diagonal direction) may be directions perpendicular to each other. 
     For example, the two coil units  230 - 1  and  230 - 2  facing each other in the first horizontal direction (or the first diagonal direction) may move the OIS operation unit in the X-axis direction by interacting with the magnet  130 , and may be referred to as “X-axis-directional OIS coils”. 
     In addition, the two coil units facing each other in the second horizontal direction (or the second diagonal direction) may move the OIS operation unit in the Y-axis direction by interacting with the magnet  130 , and may be referred to as “Y-axis-directional OIS coils”. 
     For example, the first horizontal direction may be a direction in which the two opposite side portions of the housing  140  face each other, and the second horizontal direction may be a direction in which the other two opposite side portions of the housing  140  face each other. Also, for example, the first diagonal direction may be a direction in which two opposite corners of the housing  140  face each other, and the second diagonal direction may be a direction in which the other two opposite corners of the housing  140  face each other. 
     In another embodiment, the second coil may include one coil unit located in the first horizontal direction (or the first diagonal direction) and one coil unit located in the second horizontal direction (or the second diagonal direction). In still another embodiment, the second coil may include four or more coil units. 
     Power or a driving signal may be provided to the second coil from the circuit board  250 . In an example, a first driving signal may be provided to any two coil units  230 - 1  and  230 - 2  connected in series, and a second driving signal may be provided to the other two coil units connected in series. 
     The first driving signal and the second driving signal may be a direct-current signal or an alternating-current signal, or may include a direct-current signal and an alternating-current signal, and may have the form of current or voltage. 
     Due to the interaction between the magnet  130  and the coil units, the OIS operation unit, for example, the housing  140 , may move in the second direction and/or the third direction, for example, the x-axis direction and/or the y-axis direction, thereby performing hand-tremor compensation. 
     The coil units of the second coil may be electrically connected to corresponding ones of the terminals of the circuit board  250  in order to receive a driving signal from the circuit board  250 . 
     The coil units of the second coil are implemented in the form of a circuit pattern, such as an FP coil, formed at the circuit member  231 , rather than the circuit board  250 , without being limited thereto. In another embodiment, the coil units of the second coil may be implemented in the form of a ring-shaped coil block, with the circuit member  231  omitted, or may be implemented in the form of a circuit pattern, such as an FP coil, formed at the circuit board  250 . 
     In an example, the first sensor  240   a  may overlap one of the two magnets, facing each other in the first horizontal direction, in the optical-axis direction, and the second sensor  240   b  may overlap one of the two magnets, facing each other in the second horizontal direction, in the optical-axis direction. 
     Each of the first and second sensors  240   a  and  240   b  may be a Hall sensor. Any sensor may be used, so long as the same is capable of sensing the intensity of a magnetic field. For example, each of the first and second sensors  240   a  and  240   b  may be implemented as a position detection sensor, such as a Hall sensor, alone, or may be implemented in the form of a driver including a Hall sensor. 
     The circuit board  250  may be provided with a terminal surface at which the terminals are provided. 
     According to the embodiment, the circuit board  250  may be a flexible printed circuit board (FPCB), without being limited thereto. The terminals of the circuit board  250  may be directly formed on the surface of the base  210  using a surface electrode method or the like. 
     The circuit board  250  may have therein a hole through which the support member  220  extends. The support member  220  may extend through the hole in the circuit board  250 , and may be electrically connected to the pad (or the circuit pattern) formed on the lower surface of the circuit board  250  using solder or a conductive adhesive member, without being limited thereto. 
     In another embodiment, the circuit board  250  may have no holes therein, and the support members  220  may be electrically connected to the circuit pattern or the pad formed on the upper surface of the circuit board  250  using solder or a conductive adhesive member. 
     Alternatively, in another embodiment, the support members  220 - 1  to  220 - 4  may connect the upper elastic units  150 - 1  to  150 - 4  to the circuit member  231 , and the circuit member  231  may be electrically connected to the circuit board  250 . 
     The cover member  300  accommodates the bobbin  110 , the first coil  120 , the magnet  130 , the housing  140 , the upper elastic member  150 , the lower elastic member  160 , the support member  220 , the second coil, the OIS position sensor, and the circuit board  250  in an accommodation space formed together with the base  210 . 
     The cover member  300  may be formed in the shape of a box, the lower portion of which is open and which includes an upper plate and side plates. The lower portion of the cover member  300  may be coupled to the upper portion of the base  210 . 
     The lens-moving unit  100  and the lens module  400  may include a moving unit, a fixing unit, and an elastic member connecting the moving unit to the fixing unit. 
     In an example, the moving unit may include the OIS operation unit and the lens module  400 . 
     The OIS operation unit may include the bobbin  110 , the first coil  120 , the housing  140 , and the magnet  130 . In addition, the OIS operation unit may include the AF position sensor. 
     The fixing unit may include at least one of the base  210 , the circuit board  250 , and the second coil. 
     The elastic member may include at least one of the upper elastic member  150 , the lower elastic member  160 , and the support member  220 . 
     The OIS position sensors  240   a  and  240   b  may be disposed at the fixing unit, and may output an output signal in response to the result of sensing the movement of the moving unit in a direction perpendicular to the optical axis, and the controller may acquire information about the position of the moving unit based on the output signals from the OIS position sensors  240   a  and  240   b . Hereinafter, the term “acquire” may include the meaning of any one of “receive”, “calculate”, “compute”, “extract”, or “detect”. 
       FIG. 3  is a block diagram of the lens-moving unit  100 , the motion sensor  820 , and the controller  830  of the camera module  200  shown in  FIG. 1 . 
     Referring to  FIG. 3 , the motion sensor  820  provides position information GI on the camera module  200  according to the motion of the camera module  200  to the controller  830 . 
     The position information GI on the camera module  200  may include at least one of angular speed information and acceleration information according to the motion of the camera module  200 . 
     For example, the angular speed information of the motion sensor  820  may include at least one of an X-axis angular speed, a Y-axis angular speed, and a Z-axis angular speed. Also, for example, the acceleration information of the motion sensor  820  may include at least one of X-axis acceleration, Y-axis acceleration, and Z-axis acceleration. 
     The controller  830  may generate a control signal CS for controlling the lens-moving unit  100 , and may provide the same to the lens-moving unit  100 . 
     For example, the control signal CS may include an AF driving signal, which is provided to the first coil  120  of the lens-moving unit  100 , an OIS driving signal, which is provided to the second coils  230 - 1  and  230 - 2 , and an OIS sensor control signal for driving or controlling the OIS position sensors  240   a  and  240   b.    
     In addition, the control signal CS may further include an AF sensor control signal for driving or controlling the AF position sensor. 
     The controller  830  may receive a first output signal V 1  output from the first sensor  240   a  of the lens-moving unit  100  and a second output signal V 2  output from the second sensor  240   b.    
     In addition, the controller  830  may receive a third output signal V 3  output from the AF position sensor of the lens-moving unit  100 . 
     In another embodiment, the motion sensor may be omitted from the camera module, and may be included in an optical device (e.g. a terminal  200 A), which will be described later, and the controller  830  may receive information about the rotational angular speed of the optical device from the motion sensor included in the optical device (e.g. the terminal  200 A). 
     In still another embodiment, a controller  78  included in the optical device (e.g. the terminal  200 A) may perform the operation of the controller  830 , which will be described later. 
     The controller  830  may include a hand-tremor controller for performing hand-tremor compensation on the lens-moving unit  100 . 
     When the moving unit is tilted by gravity, the hand-tremor controller may acquire a correction value for compensating for the extent of tilting of the moving unit, and may control the movement of the moving unit using the acquired correction value (or based on the correction value). At this time, the “extent of tilting” of the moving unit may be referred to as the “extent of sagging” or a “tilt angle”. 
     In an example, the hand-tremor controller may acquire a correction value for compensating for the extent of tilting (or the extent of sagging) of the “moving unit” with respect to the direction of gravity or the optical axis using posture information on the moving unit (or a posture difference thereof), and may control movement of the “moving unit” in a direction perpendicular to the optical axis based on the acquired correction value, thereby improving the accuracy of hand-tremor compensation. 
       FIG. 4  is a flowchart of a hand-tremor control method of the hand-tremor controller according to an embodiment. 
     Referring to  FIG. 4 , posture information on the moving unit is first acquired (S 10 ). 
     For example, the hand-tremor controller may receive sensing information output from the motion sensor  820  and may acquire posture information on the moving unit using the received sensing information GI. In this case, the motion sensor may be mounted to the camera module  200  or the optical device, for example, the terminal  200 A. 
     For example, the sensing information of the motion sensor  820  may be position information GI, posture information, or motion information on the camera module  200  (the optical device). 
     For example, the hand-tremor controller may acquire position information, posture information, or motion information on the camera module (or the optical device) using the sensing information of the motion sensor  820 , and may acquire posture information on the moving unit using the acquired position information, posture information, or motion information on the camera module (or the optical device). 
     The posture information on the moving unit (or the camera module or the optical device) may include a tilt angle of a reference axis at the current position of the moving unit (or the camera module or the optical device) based on the reference axis at a reference position. For example, the reference position may be a position at which the reference axis perpendicular to the sensor surface of the image sensor  810  is parallel to the direction of gravity. For example, the sensor surface may be the active area of the image sensor  810 . 
     Subsequently, a correction value is acquired using the posture information on the moving unit (S 20 ). 
     For example, the hand-tremor controller may include a memory in which correction value information on the moving unit according to the posture information on the moving unit is stored. For example, the correction value information may include at least one of the extent of tilting of the moving unit and variation in the position of the optical center of the moving unit. In addition, the hand-tremor controller may acquire a correction value using the posture information. 
     For example, the hand-tremor controller may acquire posture information on the moving unit using the Z-axis acceleration of the camera module, and may acquire tilt information on the moving unit using the posture information on the moving unit. 
     Subsequently, hand-tremor compensation is performed using the correction value. 
     The hand-tremor controller may compensate for the extent of tilting of the moving unit using the correction value. 
     For example, the hand-tremor controller may control the movement of the moving unit in a direction perpendicular to the optical axis in order to perform hand-tremor compensation. 
     For example, the hand-tremor controller may compensate for hand tremor based on the correction value during the hand-tremor compensation. 
     Alternatively, for example, the hand-tremor controller may perform hand-tremor compensation on the moving unit after compensating for the extent of tilting of the moving unit based on the correction value. 
       FIG. 5  is a configuration diagram illustrating an embodiment of the hand-tremor controller  510 . 
     Referring to  FIG. 5 , the hand-tremor controller  510  may include a position detector  512 , a target position calculator  514 , a correction value generator  515 , a driving signal generator  516 , and a driver  518 . 
     The position detector  512  may receive the output signals V 1  and V 2  output from the OIS position sensors  240   a  and  240   b  of the moving unit, for example, the lens-moving unit  100 , and may generate position information (or position data) on the moving unit based on the received output signals V 1  and V 2 . 
     For example, the position information on the moving unit may be information or data on the current position of the lens of the moving unit or the lens-moving unit  100 . For example, the position information on the moving unit may include information about two-dimensional (x,y) coordinates based on the X-axis and the Y-axis. 
     For example, the position detector  512  may generate position information on the moving unit in the X-axis direction and position information on the moving unit in the Y-axis direction based on the first output signal V 1  and the second output signal V 2 . 
     For example, the position detector  512  may include an amplifier and an analog-to-digital converter. 
     For example, the first output signal V 1  and the second output signal V 2  may be amplified by the amplifier of the position detector  512 , and the analog-to-digital converter of the position detector  512  may convert the amplified first output signal V 1  and the second output signal V 2  into digital data or digital code to generate position information PG on the moving unit. 
     The target position calculator  514  may calculate target position information (or target position data) for hand-tremor compensation using the position information GI on the camera module  200  (or the optical device), which is provided from the motion sensor  820 . 
     The “target position information” may be referred to as “target information”, a “target tilt angle”, or a “target angle”. 
     For example, the target position calculator  514  may calculate the target position information TG for hand-tremor compensation using at least one of the angular speed information and the acceleration information provided from the motion sensor  820 . 
     The target position calculator  514  may calculate the target position information TG based on the position information GI on the camera module  200  and the correction value GA provided from the correction value generator  515 . 
     For example, the target position calculator  514  may integrate at least one of the angular speed information and the acceleration information on the camera module  200 , provided from the motion sensor  820 , and may calculate an angle (or tilt) and a moving distance (shift) based on the result of integration thereof. 
     Also, for example, the target position calculator  514  may calculate target position information TG (or target position data) on the camera module  200  based on the calculated angle and/or the moving distance and the correction value provided from the correction value generator  515 . 
     The correction value generator  515  may store correction value information corresponding to the posture information on the moving unit. 
     For example, the correction value generator  515  may include a memory that stores a look-up table for storing correction value information corresponding to the posture information on the moving unit. 
     In another embodiment, a memory for storing correction value information may be provided separately from the hand-tremor controller, and may be provided in the camera module  200  or the optical device (e.g. the terminal  200 A). 
     For example, the correction value information may include at least one of the extent of tilting (or the correction value) of the moving unit, variation in the position of the optical center of the moving unit, and default variation. 
       FIG. 6A  illustrates an example of the correction value information stored in the correction value generator  515 . 
     Referring to  FIG. 6A , the correction value generator  515  may include a look-up table for storing correction value information corresponding to preset posture information on the moving unit. 
     For example, the preset posture information on the moving unit may be 90 degrees, 15 degrees, 30 degrees, 45 degrees, or 60 degrees, without being limited thereto. For example, the preset posture information may be further subdivided than what is illustrated in  FIG. 6A . 
     The look-up table may store correction values corresponding to preset respective pieces of posture information (e.g. θz=15 degrees, 30 degrees, 45 degrees, 60 degrees, and 90 degrees). 
     The correction values may include X-axis tilt angles A1 to A5 and Y-axis tilt angles B1 to B5 corresponding to preset pieces of posture information (e.g. θz=15 degrees, 30 degrees, 45 degrees, 60 degrees, and 90 degrees). 
     The correction value generator  515  may acquire current position information on the moving unit using the sensing information of the motion sensor  820 , e.g. the position information GI, or based on the sensing information. 
     The correction value generator  515  may acquire posture information on the moving unit using the sensing information provided from the motion sensor  820  or the position information GI. 
     The correction value generator  515  may detect the presence or absence of a posture difference of the moving unit, may determine the extent of the posture difference of the moving unit, and may acquire posture difference information or posture information on the moving unit using the position information GI on the camera module  200  (or the optical device) provided from the motion sensor  820 . 
     For example, the correction value generator  515  may acquire current posture information on the moving unit using the Z-axis acceleration provided from the motion sensor  820 . 
     For example, the correction value generator  515  may acquire or calculate the current posture information on the moving unit using the result of integration of the Z-axis acceleration of the camera module  200 . 
     The correction value generator  515  may acquire a correction value corresponding to the current posture information on the moving unit, which is calculated by the correction value generator  515  using the correction value information stored in the look-up table. 
     For example, referring to  FIG. 6A , when the current posture information on the moving unit acquired by the correction value generator  515  is 90 degrees, the correction value generator  515  may acquire or generate correction values A1 and B1 for compensating for sagging of the moving unit due to gravity. 
     When acquiring the target position information TG for the hand-tremor compensation of the camera module  200 , the hand-tremor controller  510  may acquire posture information on the moving unit using the Z-axis acceleration of the camera module  200  provided from the motion sensor  820 , and may generate or acquire a correction value GA for compensating for sagging of the moving unit due to gravity at a position corresponding to the acquired posture information. 
     The hand-tremor controller  510  may correct an error of the target position information TG attributable to gravity using the acquired correction value GA, thereby improving the accuracy of hand-tremor compensation. 
     The driving signal generator  516  may generate a driving control signal based on or using the target position information TG and the position information PG on the moving unit (e.g. the lens-moving unit  100 ). 
     For example, the driving signal generator  516  may acquire error information (or error data) about hand-tremor compensation based on or using the target position information TG and the position information PG on the moving unit (e.g. the lens-moving unit  100 ). 
     For example, the error information may be a difference TG-PG between the target position information TG and the position information PG on the moving unit. 
     For example, the driving signal generator  516  may generate a driving control signal DG for controlling the driver  518  based on or using the error information. 
     For example, the driving signal generator  516  may include a comparator, which compares the target position information TG with the position information PG on the lens-moving unit  100 , and a proportional integral derivative (PID) controller, which performs PID control on the output from the comparator. 
     The driver  518  may control the movement of the moving unit in a direction perpendicular to the optical axis, for example, in the X-axis direction and/or the Y-axis direction, based on the driving control signal DG. 
     For example, the driver  518  may generate a first signal for driving the X-axis-directional OIS coils of the lens-moving unit  100  and a second signal for driving the Y-axis-directional OIS coils based on the driving control signal DG. 
     For example, the driver  518  may include an amplifier for amplifying the output of the PID controller of the driving signal generator  516 , a pulse signal generator for generating a pulse signal (e.g. a PWM signal) based on the output of the amplifier, and a driver for generating the driving control signal DG based on the pulse signal, without being limited thereto. 
       FIG. 6B  illustrates another example of the correction value information stored in the correction value generator  515 . 
     Referring to  FIG. 6B , the correction value generator  515  may include a look-up table for storing variation in the optical center OC of the moving unit corresponding to the preset posture information on the moving unit. The variation in the optical center of the moving unit may include variation in the optical center in the X-axis direction and variation in the optical center in the Y-axis direction, which will be described later. 
     Variations dx to dx4 and dy to dy4 in the optical center of the moving unit corresponding to the preset pieces of posture information on the moving unit (e.g.  8   z= 15 degrees, 30 degrees, 45 degrees, 60 degrees, and 90 degrees) may be stored in the look-up table shown in  FIG. 6B . 
     The correction value generator  515  may store a function, an algorithm, or a program for acquiring a correction value corresponding to the current posture information on the moving unit using the correction value information stored in the look-up table shown in  FIG. 6B . 
     That is, the correction value generator  515  may acquire a correction value corresponding to the current posture information on the moving unit using the variations dx to dx4 and dy to dy4 in the optical center of the moving unit stored in the look-up table shown in  FIG. 6B . 
       FIG. 6C  illustrates still another example of the correction value information stored in the correction value generator  515 . 
     Referring to  FIG. 6C , the correction value generator  515  may include a look-up table for storing variation in the optical center OC of the moving unit corresponding to the preset posture information on the moving unit and default variation. The default variation may include default variation in the X-axis direction and default variation in the Y-axis direction, which will be described later. 
     The correction value generator  515  may store a function, an algorithm, or a program for acquiring a correction value corresponding to the current posture information on the moving unit using the correction value information stored in the look-up table shown in  FIG. 6C . 
     That is, the correction value generator  515  may acquire a correction value corresponding to the current posture information on the moving unit using the variations dx to dx4 and dy to dy4 in the optical center of the moving unit and the default variations dPx to dPx4 and dPy to dPy4 stored in the look-up table shown in  FIG. 6B . 
       FIG. 7  is a flowchart illustrating a method of generating the correction value stored in the correction value generator  515 . 
     Referring to  FIG. 7 , variation in the optical center OC of the moving unit having a preset posture difference is first acquired (S 110 ). 
     The posture difference of the moving unit may occur due to gravity, and the position of the optical center of the moving unit  100  may change due to the posture difference of the moving unit. 
     For example, the optical center of the moving unit  100  may be the optical center of the lens of the moving unit  100 . 
     The presence or absence of the posture difference of the moving unit and the extent of the posture difference of the moving unit may be determined based on the result of determining the posture information on the moving unit. 
       FIG. 8  illustrates a method of acquiring variation in the optical center of the moving unit shown in  FIG. 7 ,  FIG. 9  illustrates the posture difference of the moving unit and the coordinate value of the position CO of the optical center of the moving unit at the reference position, and  FIG. 10  illustrates the posture difference of the moving unit and the coordinate value of the position Cl of the optical center of the moving unit, calculated based on the preset posture information on the moving unit. 
     In order to acquire variation in the optical center OC, the position of the optical center of the moving unit at the reference position is measured (S 210 ). 
     For example, the “reference position” may be the position of the moving unit when there is no posture difference (hereinafter referred to as a “first position”). 
     Because tilting or sagging of the moving unit corresponding to the posture difference of the moving unit may occur due to gravity, the reference position may be set based on, for example, the direction of gravity  301 . 
     For example, the reference position may be the position of the moving unit when a reference axis  201  is parallel to the direction of gravity  301 . For example, the reference axis  201  may be a linear axis perpendicular to the sensor surface (e.g. the active area AR or the effective area) of the image sensor  810 . 
     Alternatively, for example, the reference position may be the position of the moving unit when the reference axis  201  is parallel to the optical axis of the moving unit. 
     For example, when the axis parallel to the direction of gravity  301  is the Z-axis, the tilt angle θz of the reference axis  201  with respect to the Z-axis at the reference position may be 0 degrees or 180 degrees. 
     When the tilt angle θz is 0 degrees, the camera module is in a state in which the lens or the bobbin is oriented in an upward direction, as shown in  FIG. 8 . On the other hand, when the tilt angle θz is 180 degrees, the camera module shown in  FIG. 8  rotates 180 degrees such that the lens or the bobbin is oriented in a downward direction. 
     For example, the moving unit may be supported by the fixing unit due to the elastic members  150  and  160  and the support member  220 . 
     When the moving unit is located at the reference position, the moving unit, for example, the OIS operation unit, may be affected only by gravity in the Z-axis direction and may not be affected in the X-axis direction or the Y-axis direction. For example, when the moving unit is located at the reference position, the optical center of the moving unit may not be affected by gravity, and thus the correction value may be 0. 
     The position of the optical center of the moving unit may be expressed as a specific coordinate value in the active area AR or the effective area of the image sensor  810 . 
     The coordinate value in the active area AR of the image sensor  810  corresponding to the position of the optical center of the moving unit at the reference position may be stored in the hand-tremor controller  510 . 
     For example, the position of the optical center of the moving unit may be defined as the coordinate value of the brightest pixel of the image sensor  810  when the light that has passed through the lens of the moving unit is sensed by the image sensor  810 . 
     For example, the brightest pixel may be the pixel having the highest pixel value, among the pixels in the effective area of the image sensor sensing the light that has passed through the lens. Here, the pixel value may be a voltage value stored in the pixel of the image sensor. 
     For example, the posture difference of the moving unit may be expressed as “posture information” on the moving unit. 
     The posture information on the moving unit may be the tilt angle θz of the reference axis  201  at a preset posture difference position of the moving unit with respect to the reference axis  201  at the reference position. For example, the preset posture difference position may be the position of the moving unit having a preset posture difference. 
     For example, the posture information on the moving unit may be the difference between the posture of the moving unit at the reference position and the posture of the moving unit at the position of the moving unit having a preset posture difference. 
     For example, the position CO of the optical center of the moving unit at the reference position may have a first coordinate value (X0,Y0). 
     Subsequently, the position of the optical center of the moving unit at the position of the moving unit having a preset posture difference is measured (S 220 ). 
     Referring to  FIG. 10 , when the preset posture difference is 90 degrees (θz=90 degrees), the elastic members  150  and  160  and the support member  220  of the moving unit are affected by gravity. As shown in  FIG. 9 , the elastic members  150  and  160  and the support member  220  may be deformed by gravity, and the moving unit may be tilted. 
     For example, when the preset posture difference is 90 degrees (θz=90), the support member  220  may be bent by gravity such that one end of the support member  220  coupled to the moving unit sags downwards. Accordingly, the moving unit may be tilted or may sag, and the position of the optical center of the moving unit may change or may move. 
     For example, one end  72  of the support member  220  may be a portion that is coupled to the upper elastic member  150 , and the other end  71  of the support member  220  may be coupled to the circuit board  250  or the base  210 . 
     For example, the extent of bending of the support member  220  at a preset posture difference position (e.g. θz=90 degrees) with respect to the support member  220  at the reference position (θz=0 degrees), at which there is no posture difference, may be referred to as the “extent of tilting” or “the extent of sagging” of the moving unit. At this time, the extent of tilting or the extent of sagging of the moving unit may be determined according to the posture difference θz of the moving unit, and the correction value may be generated based on the extent of sagging of the moving unit. 
     As shown in  FIG. 9 , when the preset posture difference of the moving unit is 90 degrees (θz=90 degrees), the position Cl of the optical center of the moving unit may have a second coordinate value (X1,Y1). 
     The position of the optical center of the moving unit at the reference position may be referred to as a “first position”, and the position of the optical center of the moving unit at the preset posture difference position may be referred to as a “second position”. 
     Subsequently, variation in the position of the optical center of the moving unit between the first position and the second position is calculated (S 230 ). 
     For example, the variation in the position of the optical center of the moving unit may be a difference between the second coordinate value (X1,Y1) at the second position and the first coordinate value (X0,Y0) at the first position. 
     For example, the variation dX in the position in the X-axis direction may be a difference X1-X0 between the X-axis coordinate value X1 at the second position and the X-axis coordinate value X0 at the first position. In addition, the variation dY in the position in the Y-axis direction may be a difference Y1-Y0 between the Y-axis coordinate value Y1 at the second position and the Y-axis coordinate value Y0 at the first position. 
     Subsequently, a correction value of the moving unit is acquired using the variation in the position of the optical center of the lens-moving unit  100  (S 120 ). 
     For example, the correction value may be generated or calculated based on the first coordinate value and the second coordinate value. 
     For example, in another embodiment, the correction value may be generated or calculated based on the variation dX in the position in the X-axis direction and the variation dY in the position in the Y-axis direction. 
     For example, in still another embodiment, the correction value may be generated or calculated based on the extent of tilting or the extent of sagging of the moving unit corresponding to the variation in the position of the optical center of the moving unit. 
       FIG. 11  illustrates an embodiment of a method of acquiring the correction value of the moving unit, and FIG. is a diagram for explaining the measurement of the default variation in the position of the optical center of the moving unit according to  FIG. 11 . 
     Referring to  FIGS. 11 and 12 , when the posture of the moving unit is tilted by a reference angle in the direction of gravity at the preset posture difference position (preset posture information), variation in the position of the optical center of the moving unit (hereinafter referred to as “default variation”) is first measured (S 310 ). 
     For example, when the support member  220  of the lens-moving unit  100  is tilted by a reference angle in the direction of gravity from the preset posture difference position (preset posture information), the default variation in the position of the optical center of the moving unit may be measured. 
     For example, the preset posture difference may be 90 degrees (θz=90 degrees), without being limited thereto. In another embodiment, the preset posture difference may be set to be greater than 0 degrees and less than 180 degrees. For example, the preset posture difference may include the posture information θz described with reference to  FIGS. 6A to 6C . 
     For example, the reference angle may be 1 degree, without being limited thereto. The reference angle may be set in order to easily calculate the extent of tilting (or the extent of sagging) and the correction value of the moving unit, and may be set to be greater than 1 or less than 1. 
     Referring to  FIG. 12 , for example, in the case of θz=90 degrees, when the support member  220  of the lens-moving unit  100  is located at a position A1, the coordinate value of the position of the optical center of the moving unit may be P1(PX1,PY1), and when the support member  200  of the lens-moving unit  100  is located at a position A2, the coordinate value of the position of the optical center of the moving unit may be P2(PX2,PY2). 
     For example, the tilt angle dθ between the support member  220  at the position A1 and the support member  220  at the position A2 may be a reference angle (e.g. 1 degree). 
     The default variation may be a difference between the coordinate value P2 and the coordinate value P1. 
     The default variation may include variation in the X-axis direction (dPx=PX2−PX1) and variation in the Y-axis direction (dPy=PY2−PY1). 
     Subsequently, a correction value of the moving unit is calculated based on the variation in the position of the optical center of the moving unit in step S 230  and the default variation in step S 310  (S 320 ). 
     For example, based on the default variation in step S 310 , the variation in the position of the optical center of the moving unit at the preset posture difference position in step S 230  may be converted into the extent of tilting or the extent of sagging θk (refer to  FIG. 8 ) of the moving unit. The extent of tilting (or the extent of sagging) may be expressed as a tilt angle (or a sagging angle), and the correction value may be expressed as a tilt angle (or a sagging angle θk), or may include a tilt angle (or a sagging angle θk). 
     For example, the tilt angle θk of the moving unit may be an angle to which the support member  220  of the lens-moving unit  100  is bent or tilted at the preset posture difference position (e.g. θz=90 degrees) with respect to the support member  220  of the lens-moving unit  100  at the reference position (θz=0). For example, the sagging angle θk may be a tilt angle with respect to one end  72  of the support member  220 . 
     For example, the tilt angle θk may be calculated based on a ratio of the variation in the position of the optical center of the moving unit at the preset posture difference position to the default variation. 
     The look-up table of the hand-tremor controller  510  may store the correction value (e.g. the tilt angle θk) acquired as described with reference to  FIGS. 8 and 11  (refer to  FIG. 6A ). 
     Alternatively, the look-up table of the hand-tremor controller  510  may store the variation in the position of the optical center of the moving unit acquired as described with reference to  FIG. 8  (refer to  FIG. 6B ). 
     Alternatively, the look-up table of the hand-tremor controller  510  may store the variation in the position of the optical center of the moving unit, acquired as described with reference to  FIGS. 8 and 11 , and the default variation in the optical center of the moving unit (refer to  FIG. 6C ). 
     The correction value generator  515  may generate a correction value corresponding to the posture information (or the posture difference) of the moving unit, acquired by the correction value generator  515 , using the look-up tables ( FIGS. 6A, 6B and 6C ). 
     For example, the correction value generator  515  may select and extract one piece of correction value information corresponding to the posture information on the moving unit, acquired by the correction value generator  515 , from among the correction value information stored in the look-up tables ( FIGS. 6A, 6B and 6C ), and may provide the extracted correction value information to the target position calculator  514 . 
     In addition, when the correction value information corresponding to the acquired posture information on the moving unit (or posture difference thereof) is not stored in the look-up tables ( FIGS. 6A, 6B and 6C ), the correction value generator  515  may calculate an approximate correction value using the correction value information in the look-up tables ( FIGS. 6A, 6B and 6C ). 
     For example, the correction value generator  515  may store a function, an algorithm, or a program for calculating an approximate correction value using the look-up tables. 
       FIG. 13  illustrates the state in which the posture difference of the moving unit is corrected by the hand-tremor controller  510 . 
     Referring to  FIG. 13 , the hand-tremor controller  510  may move and/or tilt the moving unit based on the correction value GA so that the position of the optical center of the moving unit at the posture difference position (e.g. θz=90 degrees) of the moving unit coincides with the position of the optical center of the moving unit at the reference position (e.g. θz=90 degrees). 
     For example, the hand-tremor controller  510  may control the driving signal provided to the OIS coil  230  of the moving unit based on the correction value GA, thereby controlling the electromagnetic force generated by interaction between the OIS coil  230  and the magnet  130  and compensating for tilting or sagging of the moving unit at the posture difference position of the moving unit due to gravity using the controlled electromagnetic force. 
     As described with reference to  FIG. 5 , in the process of compensating for hand tremor, it is possible to compensate for deviation of the optical center of the lens due to sagging of the lens-moving unit attributable to gravity using the correction value. 
     For example, the hand-tremor controller  510  may calculate target position information for hand-tremor compensation using the correction value, thereby compensating for deviation of the optical center of the moving unit due to tilting of the moving unit attributable to gravity. 
       FIG. 14  illustrates a hand-tremor controller  510 A according to another embodiment. 
     The same reference numerals as those in  FIG. 5  denote the same components, and a description of the same components will be made briefly or omitted. 
     Referring to  FIG. 14 , a hand-tremor controller  510 A may include a position detector  512 , a correction value generator  515 , a target position calculator  514 A, a driving signal generator  516 , and a driver  518 . 
     In another embodiment, the hand-tremor controller  510  first corrects tilting of the moving unit  100  due to gravity based on the correction value GA acquired by the correction value generator  515 . 
     For example, the driving signal generator  516  may generate a first control signal for controlling the driver  518  using the correction value GA, and the driver  518  may control electromagnetic force between the OIS coil  230  and the magnet  130  of the lens-moving unit  100  in response to the first control signal, thereby correcting tilting of the moving unit due to gravity. 
     Subsequently, in the state in which tilting attributable to gravity is corrected, the target position calculator  514 A may calculate target position information TG 1  for hand-tremor compensation using the position information GI on the camera module  200  (or the optical device) provided from the motion sensor  820  in order to compensate for hand tremor of a user or the like. 
     In addition, the driving signal generator  516  may generate a driving control signal DG using the calculated target position information TG 1  and the position information PG on the moving unit provided from the position detector  512 . In addition, the driver  518  may control the electromagnetic force between the OIS coil  230  and the magnet  130  of the lens-moving unit  100  based on the driving control signal DG to control movement of the moving unit in the X-axis direction and/or movement of the moving unit in the Y-axis direction, thereby compensating for hand tremor. 
     Even if a posture difference of the moving unit occurs due to the movement of the camera module  200  (or the optical device) (e.g. θz=90 degrees), the embodiment is capable of correcting tilting of the moving unit due to gravity using the hand-tremor controller  510 , thereby preventing deterioration in optical characteristics, e.g. the resolution, of the camera module (or the optical device) due to deviation of the optical center of the moving unit attributable to gravity during hand-tremor compensation. 
     In addition, in a camera module having two or more cameras including a lens-moving unit having an OIS function and a lens-moving unit having no OIS function, when posture differences of the lens-moving units occur, a moving unit of only the lens-moving unit having an OIS function may be tilted by gravity, which may increase tilting between the lens-moving unit having an OIS function and the lens-moving unit having no OIS function, leading to great deterioration in the performance of a dual camera capable of realizing bokeh control. 
     However, since the camera module according to the embodiment is capable of correcting tilting due to the posture difference of the OIS lens-moving unit, the relative tilt between a lens-moving unit having an OIS function and a lens-moving unit having no OIS function may be improved, and accordingly bokeh control performance may be improved. 
     As described with reference to  FIGS. 6A to 6C , the correction value information stored in the look-up tables may be a correction value of the moving unit, variation in the optical center of the moving unit, and/or default variation, without being limited thereto. 
     In another embodiment, the look-up tables may store the default variation and the position (e.g. the first coordinate value) of the optical center of the moving unit at the reference position. In addition, the hand-tremor controller may acquire posture information on the moving unit using sensing information provided from the motion sensor  820 . 
     In addition, the hand-tremor controller acquires the position of the optical center of the moving unit in real time based on the acquired posture information on the moving unit (posture difference thereof), and stores the coordinate value of the acquired position of the optical center of the moving unit in the memory. The method of acquiring the second coordinate value, described with reference to  FIG. 10 , may be equally or similarly applied to the method of acquiring the position of the optical center of the moving unit in real time. 
     Subsequently, the hand-tremor controller may acquire a correction value using the position (e.g. the first coordinate value) of the optical center of the moving unit at the reference position and the default variation, which are stored in the look-up tables, and using the position (e.g. the second coordinate value) of the optical center of the moving unit stored in the memory. 
     For example, variation in the optical center of the moving unit may be acquired using the first coordinate value and the second coordinate value, and a correction value may be acquired using the variation in the optical center of the moving unit and the default variation. The method described with reference to  FIGS. 8 and 11  may be equally or similarly applied to the correction value calculation method. 
     In addition, the camera module  200  according to the embodiment may be included in an optical instrument for the purpose of forming an image of an object present in a space using reflection, refraction, absorption, interference, and diffraction, which are characteristics of light, for the purpose of increasing visibility, for the purpose of recording and reproduction of an image using a lens, or for the purpose of optical measurement or image propagation or transmission. For example, the optical instrument according to the embodiment may be a cellular phone, a mobile phone, a smartphone, a portable smart device, a digital camera, a laptop computer, a digital broadcasting terminal, a personal digital assistant (PDA), a portable multimedia player (PMP), a navigation device, etc., without being limited thereto, and may also be any of devices for capturing images or pictures. 
       FIG. 15  is a perspective view of a portable terminal  200 A according to an embodiment, and  FIG. 16  is a configuration diagram of the portable terminal shown in  FIG. 15 . 
     Referring to  FIGS. 15 and 16 , the portable terminal  200 A (hereinafter referred to as a “terminal”) may include a body  850 , a wireless communication unit  710 , an A/V input unit  720 , a sensor  740 , an input/output unit  750 , a memory  760 , an interface  770 , a controller  780 , and a power supply  790 . 
     The body  850  may have a bar shape, without being limited thereto, and may be any of various types such as, for example, a slide type, a folder type, a swing type, or a swivel type, in which two or more sub-bodies are coupled so as to be movable relative to each other. 
     The body  850  may include a case (a casing, a housing, a cover, or the like) defining the external appearance thereof. For example, the body  850  may be divided into a front case  851  and a rear case  852 . A variety of electronic components of the terminal may be mounted in the space formed between the front case  851  and the rear case  852 . 
     The wireless communication unit  710  may include one or more modules, which enable wireless communication between the terminal  200 A and a wireless communication system or between the terminal  200 A and a network in which the terminal  200 A is located. 
     For example, the wireless communication unit  710  may include a broadcast reception module  711 , a mobile communication module  712 , a wireless Internet module  713 , a nearfield communication module  714 , and a position information module  715 . 
     The audio/video (A/V) input unit  720  serves to input audio signals or video signals, and may include a camera  721  and a microphone  722 . 
     The camera  721  may include the camera module  200  according to the embodiment. 
     The sensor  740  may sense the current state of the terminal  200 A, such as the open or closed state of the terminal  200 A, the position of the terminal  200 A, the presence or absence of a user&#39;s touch, the orientation of the terminal  200 A, or the acceleration/deceleration of the terminal  200 A, and may generate a sensing signal to control the operation of the terminal  200 A. For example, when the terminal  200 A is a slide-type phone, whether the slide-type phone is open or closed may be detected. In addition, the sensor  740  serves to sense whether power is supplied from the power supply  790  or whether the interface  770  is coupled to an external device. 
     In addition, the sensor  740  may include a motion sensor configured to output rotational angular speed information and acceleration information according to motion of the portable terminal  200 A, and the motion sensor may include a 3-axis gyro sensor, an angular speed sensor, and/or an acceleration sensor. 
     The input/output unit  750  serves to generate visual, audible, or tactile input or output. The input/output unit  750  may generate input data to control the operation of the terminal  200 A, and may display information processed in the terminal  200 A. 
     The input/output unit  750  may include a keypad unit  730 , a display module  751 , a sound output module  752 , and a touchscreen panel  753 . The keypad unit  730  may generate input data in response to input to a keypad. 
     The display module  751  may include a plurality of pixels, the color of which varies in response to electrical signals. For example, the display module  751  may include at least one of a liquid crystal display, a thin-film transistor liquid crystal display, an organic light-emitting diode, a flexible display, or a 3D display. 
     The sound output module  752  may output audio data received from the wireless communication unit  710  in a call-signal reception mode, a call mode, a recording mode, a voice recognition mode, or a broadcast reception mode, or may output audio data stored in the memory  760 . 
     The touchscreen panel  753  may convert variation in capacitance, caused by a user&#39;s touch on a specific region of a touchscreen, into electrical input signals. 
     The memory  760  may store programs for the processing and control of the controller  780 , and may temporarily store input/output data (e.g. a phone book, messages, audio, still images, pictures, and moving images). For example, the memory  760  may store images captured by the camera  721 , for example, pictures or moving images. 
     The interface  770  serves as a passage for connection between the terminal  200 A and an external device. The interface  770  may receive data or power from the external device, and may transmit the same to respective components inside the terminal  200 A, or may transmit data inside the terminal  200 A to the external device. For example, the interface  770  may include a wired/wireless headset port, an external charger port, a wired/wireless data port, a memory card port, a port for connection of a device having an identification module, an audio input/output (I/O) port, a video input/output (I/O) port, and an earphone port. 
     The controller  780  may control the general operation of the terminal  200 A. For example, the controller  780  may perform control and processing related to voice calls, data communication, and video calls. 
     The controller  780  may include a multimedia module  781  for multimedia playback. The multimedia module  781  may be provided inside the controller  180 , or may be provided separately from the controller  780 . 
     The controller  780  may perform pattern recognition processing, by which writing or drawing input to the touchscreen is perceived as characters or images. 
     The power supply  790  may supply power required to operate the respective components upon receiving external power or internal power under the control of the controller  780 . 
     The features, structures, effects and the like described above in the embodiments are included in at least one embodiment of the present disclosure, but are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects and the like exemplified in the respective embodiments may be combined with other embodiments or modified by those skilled in the art. Therefore, content related to such combinations and modifications should be construed as falling within the scope of the present disclosure. 
     INDUSTRIAL APPLICABILITY 
     The embodiments may be used in a camera module and an optical device capable of compensating for deviation of the optical center of a lens-moving unit due to gravity during hand-tremor compensation, thus preventing deterioration in resolution and improving the accuracy of hand-tremor compensation.