KR20220000394A - Lens driving unit and camera module including the same - Google Patents

Abstract

One embodiment of the lens driving device, the first magnet; a housing on which the first magnet is seated; a bobbin in which a coil is wound on an outer circumferential surface; a second magnet seated on the bobbin; and a position sensing sensor disposed opposite to the second magnet, wherein the coil is disposed at a plurality of portions on an outer circumferential surface of the bobbin to be spaced apart from each other in the first direction, and the position sensing sensor includes the second magnet and At least a portion of the opposing surface may be provided so as to be disposed between the gaps formed by the plurality of coils being spaced apart.

Description

Lens driving unit and camera module including the same}

The embodiment relates to a lens driving device and a camera module including the same.

The content described in this section merely provides background information for the embodiment and does not constitute the prior art.

In recent years, the development of IT products such as a mobile phone, a smart phone, a tablet PC, and a notebook computer with a built-in micro digital camera is being actively conducted.

In the case of a conventional IT product with a built-in miniature digital camera, an image sensor that converts external light into a digital image or digital image, and a lens driving device that performs autofocusing to align the focal length of the lens by adjusting the distance between the lens It is built-in.

Auto-focusing is performed by measuring a displacement value in the optical axis direction, that is, in the first direction by an optical axis direction displacement detecting means provided in the lens driving device, and adjusting the distance between the image sensor and the lens by a control means based on the measured displacement value can be

Therefore, it is required to develop a lens driving device having a structure capable of accurately measuring a displacement value in the first direction and a camera module including the same.

Accordingly, an object of the embodiment is to provide a lens driving device having a structure capable of accurately measuring a displacement value in the first direction, and a camera module including the same.

The technical task to be achieved by the embodiment is not limited to the technical task mentioned above, and other technical tasks not mentioned will be clearly understood by those of ordinary skill in the art to which the embodiment belongs from the description below.

One embodiment of the lens driving device, the first magnet; a housing on which the first magnet is seated; a bobbin in which a coil is wound on an outer circumferential surface; a second magnet seated on the bobbin; and a position sensing sensor disposed opposite to the second magnet, wherein the coil is disposed at a plurality of portions on an outer circumferential surface of the bobbin to be spaced apart from each other in the first direction, and the position sensing sensor includes the second magnet and At least a portion of the opposing surface may be provided so as to be disposed between the gaps formed by the plurality of coils being spaced apart.

The first magnet may be provided to face the plurality of coils.

The plurality of coils may be wound on an outer circumferential surface of the bobbin in opposite directions.

The second magnet may have an N pole and an S pole disposed in the first direction.

The second magnet may be provided by integrally combining two magnets, and each magnet may have an N pole and an S pole disposed in the first direction.

The two second magnets may have different polarities in a direction perpendicular to the first direction.

A spacer for separating the plurality of coils in the first direction may be formed on the outer circumferential surface of the bobbin along the outer circumferential surface of the bobbin.

The spacer may include at least one discontinuous portion formed on an outer circumferential surface of the bobbin so that the plurality of coils are wound in vast directions from each other, and both ends of the discontinuous portion may be provided to be spaced apart from each other.

The position sensor may be provided such that at least a portion of a surface facing the second magnet is disposed between the gaps formed by the plurality of coils being spaced apart to face the second magnet.

A magnet seating portion to which the second magnet is mounted and fixed may be formed on a side surface of the bobbin.

A pair of the first magnets may be seated on each of opposite side surfaces of the housing, and the position sensor may be seated on side surfaces other than the opposite side surfaces on which the first magnets are seated.

The pair of first magnets may be symmetrically disposed with respect to the center of the housing.

The second magnet may be disposed to be spaced apart from the position sensor by a predetermined distance in a direction perpendicular to the first direction.

It may further include a printed circuit board installed on one side of the housing.

It may further include an upper elastic member and a lower elastic member coupled to the bobbin and the housing, respectively, provided on upper and lower sides of the bobbin and the housing.

Another embodiment of the lens driving device, the first magnet; a housing on which the first magnet is seated; a bobbin in which a coil is wound on the outer circumferential surface; and a displacement sensing unit for determining a displacement value of the bobbin in the first direction, wherein the coil is provided in plurality on an outer circumferential surface of the bobbin to be spaced apart from each other in the first direction, and the first magnet includes a plurality of It may be provided to face the coil.

The displacement sensing unit may include a second magnet provided on the bobbin; and a position detection sensor provided to face the second magnet in the housing.

The position sensor may be provided such that at least a portion of a surface facing the second magnet is disposed between the gaps formed by the plurality of coils being spaced apart.

The plurality of coils are wound on the outer circumferential surface of the bobbin in opposite directions,

The position sensor may be provided such that at least a portion of a surface facing the second magnet is disposed between the gaps formed by the plurality of coils being spaced apart to face the second magnet.

One embodiment of the camera module, the lens driving device; and an image sensor mounted on the lens driving device.

In an embodiment, the interference phenomenon caused by the current flowing in the coil may be partially avoided by providing a coil avoidance portion between the second magnet and the position sensor. Accordingly, it is possible to remarkably reduce an error in sensing a displacement value in the first direction of the second magnet of the position sensor due to the interference phenomenon.

1 is a perspective view illustrating a lens driving device according to an exemplary embodiment.
2 is an exploded perspective view illustrating a lens driving device according to an exemplary embodiment.
3 is a view illustrating a state in which a coil is coupled to a bobbin in a lens driving device according to an embodiment.
4A is a view illustrating a state in which a second magnet is coupled to a bobbin in a lens driving device according to an exemplary embodiment.
4B is a front view illustrating a magnetization structure of a second magnet according to an exemplary embodiment.
4C is a front view illustrating a magnetization structure of a second magnet according to another embodiment.
5 is a view showing an arrangement state of a bobbin, a position sensor, and a second magnet in the lens driving device according to an embodiment.
6 is a view illustrating an arrangement state of a bobbin, a position sensor, a second magnet, and a coil in the lens driving device according to an embodiment.
7 is a graph illustrating a driving characteristic test result of a lens driving device according to an exemplary embodiment.

Hereinafter, an embodiment will be described in detail with reference to the accompanying drawings. Since the embodiment may have various changes and may have various forms, specific embodiments will be illustrated in the drawings and described in detail in the text. However, this is not intended to limit the embodiment to a specific disclosed form, and it should be understood to include all changes, equivalents, and substitutes included in the spirit and scope of the embodiment. In this process, the size or shape of the components shown in the drawings may be exaggerated for clarity and convenience of explanation.

Terms such as “first” and “second” may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. In addition, terms specifically defined in consideration of the configuration and operation of the embodiment are only for describing the embodiment, and do not limit the scope of the embodiment.

In the description of the embodiment, in the case where it is described as being formed in "up (up)" or "below (on or under)" of each element, on (on or under) ) includes both elements in which two elements are in direct contact with each other or one or more other elements are disposed between the two elements indirectly. In addition, when expressed as "up (up)" or "down (on or under)", the meaning of not only the upward direction but also the downward direction based on one element may be included.

Also, as used hereinafter, relational terms such as "upper/upper/above" and "lower/lower/below" etc. do not necessarily require or imply any physical or logical relationship or order between such entities or elements, It may be used only to distinguish one entity or element from another entity or element.

In addition, a Cartesian coordinate system (x, y, z) may be used in the drawings. In the drawings, the x-axis and y-axis mean a plane perpendicular to the optical axis. For convenience, the optical-axis direction (z-axis direction) may be referred to as the first direction, the x-axis direction as the second direction, and the y-axis direction as the third direction. .

1 is a perspective view schematically illustrating a lens driving device according to an exemplary embodiment. 2 is an exploded perspective view illustrating a lens driving device according to an exemplary embodiment.

An auto-focusing device applied to a small camera module of a mobile device such as a smart phone or a tablet PC is a device that automatically focuses the image of a subject on the surface of an image sensor (not shown). Such an auto-focusing device may be configured in various ways. In the embodiment, the optical module including a plurality of lenses may be moved in the first direction to perform the auto-focusing operation.

2 , the lens driving device according to the embodiment may include a movable part. In this case, the movable unit may perform an auto-focusing function of the lens. The movable part is a bobbin 110 , a first coil 120 , a first magnet 130 , a housing 140 , an upper elastic member 150 , a lower elastic member 160 , a position sensor 170 , a second magnet (180).

The bobbin 110 is provided with a first coil 120 disposed inside the first magnet 130 on an outer circumferential surface, and is used for electromagnetic interaction between the first magnet 130 and the first coil 120 . Thus, it may be installed to be reciprocally movable in the first direction in the inner space of the housing 140 .

A first coil 120 may be installed on the outer peripheral surface of the bobbin 110 to enable electromagnetic interaction with the first magnet 130 .

As shown in FIG. 2 , in the embodiment, the first coil 120 is double wound up and down on the outer peripheral surface of the bobbin 110 . That is, the first coil 120 may be disposed at a plurality of portions on the outer peripheral surface of the bobbin 110 to be spaced apart from each other in the first direction.

On the other hand, in the first magnet 130 corresponding to the first coil 120, the N pole and the S pole are arranged side by side in the first direction, and the N pole and the S pole are arranged side by side in a direction perpendicular to the first direction. have.

Meanwhile, although not shown, the first magnet 130 may have a structure in which the N pole and the S pole are disposed only in the first direction, or the N pole and the S pole are disposed only in a direction perpendicular to the first direction. .

In addition, the bobbin 110 is elastically supported by the upper and lower elastic members 150 and 160, and moves in the first direction to perform an auto-focusing function.

The bobbin 110 may include a lens barrel (not shown) in which at least one lens is installed. The lens barrel may be coupled to the inside of the bobbin 110 in various ways.

For example, a female thread may be formed on the inner peripheral surface of the bobbin 110 , and a male thread corresponding to the thread may be formed on the outer peripheral surface of the lens barrel, and the lens barrel may be coupled to the bobbin 110 by screwing them.

However, the present invention is not limited thereto, and the lens barrel may be directly fixed to the inside of the bobbin 110 by methods other than screw coupling without forming a screw thread on the inner circumferential surface of the bobbin 110 . Alternatively, the one or more lenses may be integrally formed with the bobbin 110 without a lens barrel.

The lens coupled to the lens barrel may be configured as one sheet, or two or more lenses may be configured to form an optical system.

The auto-focusing function is controlled according to the direction of the current, and the auto-focusing function may be implemented by moving the bobbin 110 in the first direction.

For example, when a forward current is applied, the bobbin 110 may move upward from the initial position, and when a reverse current is applied, the bobbin 110 may move downward from the initial position. Alternatively, the movement distance in one direction from the initial position may be increased or decreased by adjusting the amount of current in one direction.

A plurality of upper support protrusions and lower support protrusions may protrude from the upper and lower surfaces of the bobbin 110 . The upper support protrusion may be provided in a cylindrical shape or a prismatic shape, and may couple and fix the upper elastic member 150 .

The lower support protrusion may be provided in a cylindrical or prismatic shape like the upper support protrusion, and may couple and fix the lower elastic member 160 .

In this case, a through hole corresponding to the upper support protrusion may be formed in the upper elastic member 150 , and a through hole corresponding to the lower support protrusion may be formed in the lower elastic member 160 . Each of the support protrusions and the through holes may be fixedly coupled to each other by thermal fusion or an adhesive member such as epoxy.

The housing 140 has a hollow column shape supporting the first magnet 130 , and may be formed in a substantially rectangular shape. A first magnet 130 may be coupled to the housing 140 to be disposed. Also, as described above, a bobbin that is supported by the housing 140 and moves in the first direction may be disposed on the inner circumferential surface of the housing 140 .

The housing 140 may have four flat sides. The side surface of the housing 140 may be formed to have an area corresponding to or larger than that of the first magnet 130 . A through hole or groove for a magnet in which the first magnet 130 is seated may be provided on each of the opposite side surfaces of the four side surfaces of the housing 140 .

As shown in FIG. 2 , two first magnets 130 on each side in the first direction were mounted on the housing 140 up and down. Accordingly, the through-holes or grooves for magnets of the housing 140 may also be provided in a corresponding number.

Accordingly, the pair of first magnets 130 may be disposed symmetrically with respect to the center of the housing 140 .

If the first magnets 130 are disposed to face each other while being biased to one side regardless of the center of the housing 140, electromagnetic force acts on the coil 120 of the bobbin 110 to be biased to one side, so the bobbin ( 110) is likely to be tilted.

Accordingly, it is appropriate that the pair of first magnets 130 are symmetrically disposed with respect to the center of the housing 140 .

In addition, a through hole for a sensor in which the position detection sensor 170, which will be described later, is seated, may be provided on a surface other than the side on which the first magnet 130 is seated among the four side surfaces of the housing 140 .

Accordingly, the first magnet 140 is seated on each of the opposite side surfaces of the housing 140 among the four side surfaces of the housing 140, and on the side surfaces other than the opposite side surfaces on which the first magnet 140 is seated, the The position sensor 170 may be seated.

The upper elastic member 150 and the lower elastic member 160 may be coupled to the bobbin 110 and the housing 140 , and may be provided above and below the bobbin 110 and the housing 140 , respectively. .

The upper elastic member 150 and the lower elastic member 160 may elastically support the ascending and/or descending operation of the bobbin 110 in the first direction. The upper elastic member 150 and the lower elastic member 160 may be provided as leaf springs.

As shown in FIG. 2 , the lower elastic member 160 may be provided in two pieces separated from each other. Through this two-division structure, each of the divided portions of the lower elastic member 160 may receive currents having different polarities or different power sources.

Also, as a modified embodiment, the upper elastic member 150 may have a two-part structure, and the lower elastic member 160 may have an integrated structure.

Meanwhile, the upper elastic member 150 , the lower elastic member 160 , the bobbin 110 , and the housing 140 may be assembled through thermal fusion and/or bonding using an adhesive or the like. In this case, for example, the fixing operation may be finished by bonding using an adhesive after fixing by thermal fusion.

The position detecting sensor 170 may be a displacement detecting unit that determines a displacement value of the bobbin 110 in the first direction together with a second magnet 180 of the bobbin 110 to be described later. To this end, the position detection sensor 170 and the through hole for the sensor may be disposed at a position opposite to the position of the second magnet 180 .

The position sensor 170 may be a sensor that detects a change in magnetic force emitted from the second magnet 180 of the bobbin 110 . In addition, the position sensor 170 may be a Hall sensor.

However, as an example, this embodiment is not limited to the Hall sensor, and any sensor capable of detecting a change in magnetic force can be used, and any sensor capable of detecting a position other than magnetic force is possible, for example For example, a method using a photoreflector or the like is also possible.

The second magnet 180 may be coupled to the bobbin 110 . Accordingly, the second magnet 180 may move in the first direction by the same amount of displacement as the bobbin 110 when the bobbin 110 moves in the first direction.

In addition, the second magnet 180 may be configured as a single body, and the upper direction of the bobbin 110 may be an N pole and a lower direction of the bobbin 110 may be an S pole. However, the present invention is not limited thereto, and the reverse configuration is also possible.

In addition, as the second magnet 180 , one magnet may be used, or two or more magnets may be integrally combined to be used. A specific structure of the second magnet 180 will be described later with reference to FIGS. 4B and 4C .

In addition, the second magnet 180 may be divided into two in a plane perpendicular to the optical axis. The second magnet 180 may be disposed to be spaced apart from the position sensor 170 by a predetermined distance in a direction perpendicular to the first direction.

The base 210 is disposed under the bobbin 110 , and may be provided in a substantially rectangular shape, and the printed circuit board 250 and the lower elastic member 160 may be seated thereon.

In addition, the cover member 300 may be coupled to the upper portion of the base 210 , and the base 210 and the cover member 300 may be fixed and sealed at respective ends in contact with each other by an adhesive or the like.

The printed circuit board 250 may be coupled to one side of the housing 140 . A terminal surface 253 may be formed on the printed circuit board 250 .

A plurality of terminals 251 are disposed on the terminal surface 253 to supply current to the coil 120 and the position sensor 170 of the bobbin 110 by receiving external power. The number of terminals 251 formed on the printed circuit board 250 may increase or decrease according to the types of components that need to be controlled. Meanwhile, according to the present embodiment, the printed circuit board 250 may be provided as an FPCB.

The printed circuit board 250 may include a control unit that readjusts the amount of current applied to the coil 120 based on the displacement value sensed by the displacement sensing unit.

That is, the control unit may be mounted on the printed circuit board 250 . In addition, in another embodiment, the control unit may be mounted on a separate board rather than on the printed circuit board 250 , which may be a board on which the image sensor of the camera module is mounted, or may be a separate board. have.

The cover member 300 may be provided in a substantially box shape, accommodate the above-described movable part, a part of the printed circuit board 250 , and the like, and may be coupled to the base 210 .

The cover member 300 protects the movable part accommodated therein, the printed circuit board 250, etc. from being damaged, in particular, generated by the first magnet 130 and the first coil 120 accommodated therein. It is possible to condense the electromagnetic field by limiting the leakage of the electromagnetic field to the outside.

3 is a view showing a state in which the coil 120 is coupled to the bobbin 110 in the lens driving device according to an embodiment. As shown in FIG. 3 , in the embodiment, a plurality of coils 120 may be provided on the outer peripheral surface of the bobbin 110 to be spaced apart from each other in the first direction. In FIG. 3 , the coil 120 is double disposed in the first direction as an embodiment.

In order to maintain a gap formed by a plurality of coils 120 spaced apart from each other and stably maintain a state in which the coils 120 are wound around the outer circumferential surface of the bobbin 110, the bobbin 110 A separation portion 111 may be formed on the outer circumferential surface.

3, the spacer 111 is formed along the outer circumferential surface of the bobbin 110 in the middle portion of the outer circumferential surface of the bobbin 110, and may be formed to have a constant width in the first direction, , the first direction width of the spacing portion 111 may be the first direction spacing gap between the plurality of coils 120 .

The spacing part 111 is formed along the outer peripheral surface of the bobbin 110, and may be formed integrally by protruding from the bobbin 110, and as described above, the plurality of coils 120 are formed on the bobbin ( 110) may serve to be spaced apart from the outer circumferential surface with a predetermined spacing gap in the first direction.

Meanwhile, as shown in FIG. 2 , as the coil 120 is disposed at a plurality of portions on the outer circumferential surface of the bobbin 110 , the first magnet 130 corresponding to the coil 120 is provided in plurality or It is provided by polarizing one magnet, and may be provided to face the plurality of coils 120 .

In this case, the plurality of coils 120 may be wound on the outer circumferential surface of the bobbin 110 in opposite directions. In order to increase the magnetic force of the first magnet 130, the first magnets 130 provided to face each of the plurality of coils 120 are disposed to have different polarities on the surfaces facing each other in the first direction. proper.

Accordingly, in order to match the direction of the force generated by the coil 120 and the first magnet 130 according to Fleming's left hand rule, it is necessary to form different directions of current flowing through the plurality of coils 120. to be.

Accordingly, for example, the upper coil 120 of the plurality of coils 120 is wound around the outer peripheral surface of the bobbin 110 in a clockwise direction when viewed in the first direction, and the lower coil 120 is wound around the outer peripheral surface of the bobbin 110 in a clockwise direction when viewed in the first direction. It may be wound around the outer peripheral surface of the bobbin 110 in a counterclockwise direction.

Also, conversely, the upper coil 120 may be wound on the outer peripheral surface of the bobbin 110 in a counterclockwise direction when viewed in the first direction, and the lower coil 120 may be wound around the bobbin 110 in a clockwise direction.

4A is a view showing a state in which the second magnet 180 is coupled to the bobbin 110 in the lens driving device according to an embodiment.

As described above, the second magnet 180 may constitute a displacement detecting unit for detecting a displacement value of the bobbin 110 in the first direction together with the position detecting sensor 250 provided to face it.

In this case, the second magnet 180 may be provided on the bobbin 110 in the embodiment. For this, a magnet seating part ( 113) may be formed.

As shown in FIG. 4A , the magnet seating part 113 may have a size and shape in which the second magnet 180 can be seated and fixed on the side of the bobbin 110 . For example, the magnet seating part 113 may be formed in a groove shape in which a portion of the side surface of the bobbin 110 is recessed.

The second magnet 180 may be seated on the magnet mounting part 113 and fixed to the bobbin 110 by an adhesive or the like. At this time, the separation portion 111 is cut off in the region where the magnet seating portion 113 is formed.

Even if the coil 120 is wound on the outer peripheral surface of the bobbin 110, the second magnet 180 is the same as the upper and lower gaps between the plurality of coils 120 at the portion where the spacer 111 is cut. It can have an avoidance part.

Accordingly, the second magnet 180 fixed to the bobbin 110 is provided to directly face the position detection sensor 250 at the avoiding portion of the coil 120 among the surfaces facing the position detection sensor 250 . can be In addition, the second magnet 180 may be provided so that the sensing portion of the position detection sensor 250 faces.

As described above, by providing a coil 120 avoidance portion in which the coil 120 is not interposed between the second magnet 180 and the position detection sensor 250, the second magnet 180 and the position detection sensor Reference numeral 250 is provided to face directly without interference from the coil 120 , and accordingly, it is possible to reduce the sensing error value of the position sensor 250 caused by the interference of the current flowing through the coil 120 .

4B is a front view showing the magnetization structure of the second magnet 180 according to an embodiment. 4C is a front view showing the magnetization structure of the second magnet 180 according to another embodiment.

As shown in FIG. 4B , the second magnet 180 according to an embodiment is composed of one magnet, and the second magnet 180 may be provided such that the N pole and the S pole are disposed in the first direction. have.

In this case, the second magnet 180 may have an N pole disposed on the upper side and an S pole disposed on the lower side, or conversely, the S pole may be disposed on the upper side and the N pole may be disposed on the lower side.

As shown in FIG. 4C, the second magnets 180-1 and 180-2 according to another embodiment are magnetized with four N or S poles formed as if one magnet were integrally combined with the magnets of FIG. 4B. Having a structure, each magnet may be provided so that the N pole and the S pole are arranged in the first direction.

In this case, the second magnets 180 - 1 and 180 - 2 may have different polarities in a direction perpendicular to the first direction.

That is, the N pole of some of the second magnets 180 - 1 disposed on the right side of the drawing may be disposed on the upper side and the S pole disposed on the bottom side, and the second magnet 180 of another part disposed on the left side of the drawing. The S pole of -2) may be disposed on the upper side and the N pole may be disposed on the lower side.

Conversely, the S pole of some of the second magnets 180 - 1 disposed on the right side of the drawing may be disposed on the upper side and the N pole may be disposed on the bottom side, and another part of the second magnet 180 disposed on the left side of the drawing The N pole of -2) may be disposed on the upper side and the S pole may be disposed on the lower side.

5 is a view showing the arrangement of the bobbin 110, the position sensor 250, and the second magnet 180 in the lens driving device according to an embodiment.

The second magnet 180 may be seated on a side surface of the bobbin 110 , and the position sensor 250 may be seated on the housing 140 and disposed to face the second magnet 180 .

The second magnet 180 moves in the first direction together with the bobbin 110 as the bobbin 110 moves in the first direction, and the position sensor 250 seated in the housing 140 is By sensing a change in magnetic force generated as the second magnet 180 moves in the first direction, displacement values of the second magnet 180 and the bobbin 110 in the first direction may be sensed.

On the other hand, since the coil 120 is interposed between the second magnet 180 and the position sensing sensor 250 , the opposite surfaces of the second magnet 180 and the position sensing sensor 250 are the first It may be arranged to be spaced apart by a predetermined distance in a direction perpendicular to one direction.

6 is a view showing an arrangement state of the bobbin 110 , the position sensor 250 , the second magnet 180 , and the coil 120 in the lens driving device according to an embodiment.

As described above, a plurality of coils 120 are wound on the outer circumferential surface of the bobbin 110 in a first direction, and the upper coil 120 and lower coil 120 are constant in the first direction by the spacer 111 . It is disposed to have a gap, and the upper coil 120 and the lower coil 120 may be wound in opposite directions.

The position sensor 250 is disposed between the gap formed by the plurality of coils 120 spaced apart at least a portion of the surface opposite to the second magnet 180 to directly face the second magnet 180 . It can be provided for viewing.

That is, even when the coil 120 is wound on the outer peripheral surface of the bobbin 110 , the second magnet 180 is formed between the upper and lower gaps between the upper coil 120 and the lower coil 120 and the second magnet 180 . The coil 120 avoidance portion may be provided in which the coil 120 is not interposed as much as an area formed by a width in a direction perpendicular to the first direction.

Accordingly, by providing a coil 120 avoidance portion in which the coil 120 is not interposed between the second magnet 180 and the position sensing sensor 250 , the second magnet 180 and the position sensing sensor 250 are provided. ) may be provided to face directly without interference of the coil 120 .

When the coil 120 is interposed between the second magnet 180 and the position sensor 250 , the current flowing in the coil 120 distorts the structure and strength of the magnetic field formed by the second magnet 180 . interference may occur.

Due to this interference phenomenon, the position sensor 250 is distorted by the current flowing in the coil 120 rather than the correct magnetic field formed by the second magnet 180 when the second magnet 180 moves in the first direction. changes in the magnetic field are sensed.

For this reason, a sensing error occurs in the position detection sensor 250 , and consequently, the position detection sensor 250 cannot accurately detect the displacement value of the second magnet 180 in the first direction.

In the embodiment, as described above, an avoidance portion of the coil 120 is provided between the second magnet 180 and the position sensor 250 to partially reduce the interference phenomenon caused by the current flowing in the coil 120 . can be avoided with

Accordingly, it is possible to remarkably reduce a sensing error of the displacement value in the first direction of the second magnet 180 of the position sensor 250 due to the interference phenomenon.

7 is a graph illustrating a driving characteristic test result of a lens driving device according to an exemplary embodiment. In the graph, the gain GAIN may be converted into a displacement value in the first direction of the second magnet 180 through appropriate conversion into a value sensed by the position detection sensor 250 .

In the graph, the gain of the lens driving device of the embodiment in which the coil 120 avoidance unit is provided is indicated by L1. In the graph, since one coil 120 is wound around the outer peripheral surface of the bobbin 110 , the gain of the lens driving device without the coil 120 avoidance portion is indicated by L2 .

In the graph, the phase PHASE can be drawn using the phase difference between the current input value of the coil 120 and the output value of the position sensor 170 , and in the graph, the phase is indicated by L3 .

Since the displacement value in the first direction of the second magnet 180 and the displacement value in the first direction of the bobbin 110 coincide, as L1 or L2 matches L3, the sensing value error of the position sensor 250 can be reduced. have.

Considering section A in the graph, it can be seen that the L3 graph continuously decreases as the frequency (FREQUENCY) increases. However, it can be seen that the L1 or L2 graph in section A has an increasing section.

Again, compare the L1 and L2 graphs in section A. As the frequency increases, the gain of L1 increases significantly compared to L3, and the increase width shows a generally constant trend.

As the frequency increases, the gain of L2 increases compared to L3, but the increase is significantly lower than that of L1, and the gain decreases as the frequency becomes higher after the increase.

Comparing the L1 and L2 graphs, L2 shows a trend closer to L3 than L1. As a result, the lens driving device of the embodiment having the coil 120 avoidance part has a sensing error of the position sensor 250 due to the current flowing through the coil 120 compared to the lens driving device not provided with the coil 120 avoidance part. It shows that the value is small.

On the other hand, the first direction displacement value sensing error of the position detection sensor 250 due to the difference between the gain of the lens driving device of the embodiment and the phase indicating the current input value of the coil 120 is significantly reduced by reference point calibration (calibration) I can get rid of it.

Meanwhile, the lens driving apparatus according to the above-described embodiment may be used in various fields, for example, a camera module. For example, the camera module may be applied to a mobile device such as a mobile phone.

The camera module according to the embodiment may include a lens barrel coupled to the bobbin 110 , an image sensor (not shown), a printed circuit board 250 , and an optical system.

The lens barrel is the same as described above, and the printed circuit board 250 may form the bottom surface of the camera module from the portion where the image sensor is mounted.

In addition, the optical system may include at least one lens that transmits an image to the image sensor. In this case, an actuator module capable of performing an auto-focusing function and a hand-shake correction function may be installed in the optical system. The actuator module performing the auto-focusing function may be configured in various ways, and a voice coil unit motor is generally used. The lens driving apparatus according to the above-described embodiment may serve as an actuator module that performs both an auto-focusing function and a hand-shake correction function.

In addition, the camera module may further include an infrared cut filter (not shown). The infrared cut filter serves to block light in the infrared region from being incident on the image sensor. In this case, in the base 210 illustrated in FIG. 2 , an infrared cut filter may be installed at a position corresponding to the image sensor, and may be coupled to a holder member (not shown). In addition, the base 210 may support the lower side of the holder member.

A separate terminal member may be installed on the base 210 to conduct electricity with the printed circuit board 250 , and it is also possible to integrally form the terminal using a surface electrode or the like. Meanwhile, the base 210 may function as a sensor holder to protect the image sensor, and in this case, a protrusion may be formed in a downward direction along the side surface of the base 210 . However, this is not an essential configuration, and although not shown, a separate sensor holder may be disposed under the base 210 to perform its role.

Although only a few have been described as described above in relation to the embodiments, various other forms of implementation are possible. The technical contents of the above-described embodiments may be combined in various forms unless they are incompatible with each other, and may be implemented in a new embodiment through this.

110: bobbin
111: separation part
112: both ends of the discontinuous part
113: magnet seating part
120: coil
130: first magnet
140: housing
150: upper elastic member
160: lower elastic member
170: position sensor
180: second magnet
250: printed circuit board

Claims (20)

a first magnet;
a coil facing the first magnet;
a bobbin in which the coil is wound on an outer circumferential surface;
a second magnet disposed on the bobbin; and
and a position detection sensor disposed to face the second magnet,
The coil is disposed between the second magnet and the position sensor,
A part of the second magnet is not covered by the wound coil and is exposed to directly face the position sensor in a first direction perpendicular to the optical axis direction. According to claim 1, wherein the bobbin comprises a magnet seat formed on the outer peripheral surface,
The second magnet is a lens driving device disposed on the magnet seating portion. The lens driving device of claim 2 , wherein the magnet seating part has a groove shape in which a part of the outer peripheral surface is recessed. The lens driving device of claim 1 , wherein the other part of the second magnet faces the position sensor in the first direction while being covered by the wound coil. The lens driving apparatus according to claim 1, wherein the other part of the second magnet, the coil, and the position sensor overlap in the first direction. 3. The method of claim 2, wherein the coil is
a plurality of coils disposed to be spaced apart from each other with a gap therebetween in a second direction parallel to the optical axis direction on the outer peripheral surface of the bobbin,
The part of the second magnet is exposed through a part of the gap to directly face the position sensor. The method of claim 6, wherein the bobbin
and spaced apart the plurality of coils in the second direction, and a spacer formed along the outer circumferential surface. The lens driving device of claim 7 , wherein the separation part is cut off from the magnet seating part. The lens driving device of claim 8 , wherein a coil avoidance portion that is a portion of the gap exposing the portion of the second magnet extends in a circumferential direction of the spacer and the bobbin. 7. The method of claim 6,
The plurality of coils are wound on the outer peripheral surface of the bobbin in opposite directions to each other. 11. The method of claim 10,
The second magnet is a lens driving device in which an N pole and an S pole are disposed in the second direction. 11. The method of claim 10,
The second magnet includes two magnets integrally coupled,
Each of the two magnets has an N pole and an S pole disposed in the second direction. 13. The method of claim 12,
The two second magnets are disposed to have different polarities in a third direction perpendicular to each of the first and second directions. 8. The method of claim 7,
The separation part,
A lens driving device formed at an intermediate portion in the second direction from the outer circumferential surface of the bobbin and having a constant width in the second direction. According to claim 1,
and a housing in which the first magnet is disposed,
A pair of the first magnets are disposed on each of opposite side surfaces of the housing,
A lens driving device in which the position sensor is disposed on a side surface of the housing other than the both side surfaces on which the first magnet is disposed. 16. The method of claim 15,
The pair of first magnets are disposed to be symmetrical to each other with respect to the center of the housing. a first magnet;
a coil facing the first magnet;
a bobbin in which the coil is wound on an outer circumferential surface; and
and a displacement detection unit for sensing a displacement value of the bobbin in the optical axis direction,
The displacement sensing unit,
a second magnet disposed on the bobbin; and
and a position detection sensor disposed to face the second magnet,
The coil is disposed between the second magnet and the position sensor,
A lens driving device in which a portion of the second magnet directly faces the position sensor without being blocked by the coil in a direction perpendicular to the optical axis direction. a first magnet;
a coil facing the first magnet;
a bobbin in which the coil is wound on an outer circumferential surface;
a second magnet disposed on the bobbin; and
A lens driving device including a position detection sensor disposed to directly face a part of the second magnet. The lens driving device according to any one of claims 1 to 18; and
A camera module including an image sensor mounted on the lens driving device. A mobile device comprising the camera module of claim 19 .

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