KR20110068504A - Low cost manufacturing and compact lens actuator - Google Patents

Abstract

The present invention relates to a lens actuator of a voice-coil motor (VCM) type that can be mounted on a mobile device. The lens actuator of the present invention is configured such that a shield case for preventing influence from external electronic components can be substituted for the function of the yoke without adopting the yoke for controlling the magnetic force generated from the magnet as an essential component. On the other hand, the unique arrangement and shape of the magnet allows a much more compact configuration than the conventional lens assembly.

Description

Lens Actuators Fabricated with Low Cost and Small Size

The present invention relates to a lens actuator constituting a camera module, and more particularly, to a lens actuator of a VCM method that can be mounted on a mobile device and can be manufactured at a low cost and miniaturized.

Recently, with the rapid development of information and communication technology, a camera module is mounted as a precise small optical system in a mobile communication device such as a mobile phone. Accordingly, a camera, which is an apparatus for photographing a subject through a lens, is also applied to these mobile communication devices.

However, like conventional cameras, the camera module employed in these small mobile communication devices requires an actuator as a driving device for precisely controlling the focus on the subject by moving a plurality of lenses in the optical axis direction. Do.

Conventionally, a mechanical device using a rotating motor method for converting a rotational motion of a motor into a linear motion has been proposed as an actuator for automatically adjusting a focus on a subject in a camera module mounted on a compact optical device. However, it is difficult to finely adjust the focus along with the problem of friction between the gear and the motor in the mechanical device, and it is difficult to miniaturize due to the space problem occupied by each mechanical device. Accordingly, there have been many problems in applying actuators adopting these mechanical methods to mobile communication devices that are becoming smaller and lighter.

Therefore, in order to clearly see a subject in an optical system of a camera module mounted on a gradually miniaturizing mobile communication device, various methods have been proposed instead of the conventional mechanical method. However, even in a lens actuator that constitutes a camera module adopted in a mobile communication device, it is necessary to adjust a distance between a plurality of lenses and an image sensor that actually forms an image on a subject or to change an image's curvature so that an image is clearly formed on the image sensor. Focusing should be performed. As a separate driving module for implementing such focusing, a method such as a manual, stepper motor, piezoelectric element, and voice coil motor is adopted.

The voice coil motor (VCM), also called a voice coil actuator (VCA), refers to a method of precisely adjusting the focus on a subject using an induction magnetic force between a permanent magnet and a coil. Currently, mobile communication devices generally adopt camera modules using VCM.

FIG. 1 is a perspective view schematically showing a coupling relationship between components of a lens actuator employing a VCM method, which is proposed in Patent Application No. 10-0919117 filed by the applicant of the present invention, and FIG. 2 is an interior of the lens actuator. It is cut. As shown in the drawings, the conventional VCM lens actuator 1 includes a lens unit 10 composed of one or more lenses L1, L2, L3, and L4, and a carrier fastened to an outer periphery of the lens unit 10 ( 12), the elastic bodies 14 and 16 for pressing the upper and lower ends of the carrier 12, and the outside of the carrier 12 to move the carrier 12 in the optical axis direction to adjust the focus on the image to be captured. A drive unit 20 disposed along the periphery, an upper cover 32 formed through the guide 15 to the upper end of the upper elastic body 14, and a lower cover 34 formed at the lower end of the carrier 12; , An image sensor mounted on the base 40 supporting the carrier 20 and the driving unit 20, the filter 50 coupled to the lower inner circumferential surface of the base 40, and the substrate 70 bonded by a bonding agent. (60).

At this time, the driving unit 200 interacts with the magnet 22 generating magnetic force and the yoke 24 for controlling the magnetic force generated from the magnet 22 and a predetermined current are applied to the magnetic force generated in the magnet 22. And a driving coil 26 generating a driving force by electromagnetic force, and the driving unit 20 is disposed along the outer periphery of the carrier 12.

By the way, the following problems are exposed in the case of the conventional lens actuator 1 of the VCM system comprised in this way. First, in order to smoothly drive the lens actuator 1 of the conventional VCM method, it is necessary to control the direction of the magnetic field generated from the magnet 22 only in a certain direction, and for this purpose, the yoke 24 is provided around the magnet 22. ) Is essentially formed. By the way, it is necessary to reduce the size of the driving unit 20 which is the core of the lens actuator forming the camera module mounted therein according to the mobile communication device which is gradually miniaturized, but the driving unit 20 has a constant size in order to exhibit a smooth driving force. Since it must have a limit in reducing the size of the drive unit 20. Therefore, when the magnet 22, the yoke 24 and the drive coil 26 are adopted as essential components of the drive unit 20, the size of the lens actuator 1 is no longer reduced due to the space occupied by these drive units. Do.

In addition, since the upper cover 32 and the lower cover 34 should be interposed between the upper and outer peripheral surfaces and the lower end of the driving unit 20 so that the driving unit 20 does not deviate in the process of assembling the conventional lens actuator 1. The number of component parts constituting the actuator 1 increases, which not only increases the assembly process but also limits the efforts to miniaturize the lens actuator 1.

Moreover, not only the camera module is mounted on the mobile communication device in which the lens actuator 1 is mounted, but also the various electronic components are assembled in a highly compact form. By the way, in the conventional lens actuator 1, no other means for shielding the lens actuator 1 from the influence of electromagnetic waves or the like generated by external electronic components is not provided. Accordingly, the possibility of the lens actuator 1 malfunctioning due to the influence of electromagnetic waves generated from an external electronic component formed adjacent to the camera module cannot be excluded.

SUMMARY OF THE INVENTION The present invention has been proposed to solve the above problems, and an object of the present invention is an electromagnetic wave generated from separate external electronic components mounted on the outside of these camera modules in a lens actuator for a mobile device adopting a so-called VCM method. It is an object of the present invention to provide a lens actuator that can be easily assembled and miniaturized while excluding the influence of the present invention.

It is another object of the present invention to provide a lens actuator for a mobile communication device that can also precisely control a subject through a method of easily assembling various component parts that are difficult to assemble and reducing the number of component parts.

Other objects and advantages of the present invention will become more apparent from the drawings and accompanying drawings.

In the present invention having the above object is provided with a shield case for controlling the magnetic force generated from the magnet in the lens actuator for a mobile device of the VCM method and at the same time to suppress the influence of the lens actuator by an external electronic component.

Specifically, the present invention includes a lens module including a carrier for accommodating the lens unit to photograph the subject; A driving unit for moving the lens module along an optical axis direction by an interaction between a magnet disposed along an outer circumferential surface of the carrier and a driving coil; A polyhedral shape having a hollow portion, the shield case covering a top surface of the magnet and forming a shielding portion extending along an outer circumferential surface of the magnet and the driving coil in an optical axis direction; It provides a lens actuator for a mobile device comprising a base for supporting the carrier and the bottom of the drive unit.

At this time, the upper end of the carrier is a cylindrical shape, the interruption of the carrier has a polygonal flat cross-section, the magnet is characterized in that a plurality of bar (bar) formed along the outer peripheral surface of the upper end of the carrier. Further, the drive coil preferably has a polygonal flat cross-sectional shape corresponding to the interrupted outer circumferential surface of the carrier to be formed along the carrier interrupted outer circumferential surface having a polygonal flat cross-section. According to a particularly preferred aspect the suspension of the carrier and the drive coil may have a flat cross-sectional shape of a square.

According to an embodiment of the present invention, a yoke, which is interposed between an outer circumferential surface of the driving coil and an inner circumferential surface of the shielding part of the shield case and extends along the optical axis direction from the bottom of the magnet, is formed in the shape of the driving coil and the shield case. It can be formed in a corresponding shape to double the driving force.

In addition, the lens actuator of the present invention further comprises an elastic means for contacting the upper and lower ends of the carrier, respectively, the elastic means is a first elastic body for pressing the upper end of the carrier, the second pressing the lower end of the carrier It includes an elastic body.

In addition, the lens actuator of the present invention may further include a cover disposed on the upper end of the first elastic body so that the first elastic body can press the upper end of the carrier. If the magnet has a plurality of bar (bar) shape is formed along the upper outer peripheral surface of the carrier, each portion of the cover is characterized in that it is interposed between each magnet in the form of the plurality of bars extending downward.

In addition, the base has a four-sided flat cross-section with a window formed in the center, each corner is characterized in that it is extended upwardly coupled to the outer circumferential surface of the corner region of the shield case.

In the present invention, in the lens actuator for mobile devices adopting the Voice Coil Motor (VCM) method, a shield case is provided for guiding the direction of the magnetic field generated from the magnet in a certain direction and excluding the influence of external electronic components. The shield case is configured to be directly coupled to the base without a separate coupling part.

Accordingly, the lens actuator of the present invention may be relatively free from the influence of external electronic components, and it is necessary to form a separate lower cover interposed between the yoke or base and the carrier for controlling the magnetic force generated from the magnet. This reduces the number of components and reduces the size of the entire lens actuator because no space is required by these components.

Therefore, it can be applied to the camera module mounted on the mobile communication device in accordance with the trend of the mobile communication device that is gradually miniaturized, it is easy to assemble between the components can be precise control of the subject.

The present inventors have completed the present invention after recognizing the problems of the lens actuator constituting the camera module adopted in the conventional mobile communication device described above, and diligently researching a solution thereof. Hereinafter, the present invention will be described with reference to the accompanying drawings. The preferable aspect of the following is demonstrated concretely.

3 is an exploded perspective view schematically illustrating a coupling relationship between components constituting a lens actuator constituting a camera module adopted in a mobile communication device according to an embodiment of the present invention, and FIG. 4 is a lens according to the present embodiment. An overall perspective view of the actuator assembled, and FIG. 5 is a cross-sectional view taken along the line VV of FIG. 4. A lens actuator mounted to a mobile communication device according to the present embodiment will be described with reference to FIGS. 2 to 4 simultaneously.

The lens actuator 100 according to the present exemplary embodiment is a lens module including a lens unit 210 including one or more lenses and a carrier 220 fastened to an outer circumferential surface of the lens unit 210 to accommodate the lens unit 210. An elastic force for pressing the upper and lower ends of the driving unit 300 and the carrier 220 disposed along the outer periphery of the carrier 220 to form a driving force for moving the lens module 200 in the optical axis direction (200). Means 410 and 420, a cover 510 formed on the upper end of the driving unit 300, a shield case 600, a carrier 220 and a driving unit (shape surrounding the driving unit 300 and the cover 510) A base 700 supporting the bottom of the 300, a filter 810 fastened to an inner circumferential surface of the base 700, and an image sensor 820 are included.

The lens unit 210 that forms the center of the lens actuator 100 according to the present embodiment is mounted in a form in which a plurality of lenses are assembled so that their optical axes coincide with each other. The lens unit 210 may be composed of a plurality of lenses having different diameters and curvatures, for example, four lenses L1, L2, L3, and L4. The lens unit 210 may be formed by, for example, a press molding method. It may be assembled inside the barrel of the metal or plastic to be manufactured. The lens unit 210 has a hollow cylindrical shape, and the carrier 220 having a hollow upper end thereof is fastened to form a lens module 200. Threads 212 and 222 are formed on the outer circumference of the lens unit 210 and the inner circumferential surface of the carrier 220, respectively, for firm coupling between the lens unit 210 and the carrier 220.

Meanwhile, according to the present exemplary embodiment, the carrier 220 constituting the lens module 200 has a unique shape. As shown in FIG. 2, the inner circumferential surface of the carrier 220 is cylindrical so as to accommodate the cylindrical lens unit 210, but the outer circumferential surface of the carrier 220 is not a simple cylindrical shape. That is, the upper outer circumferential surface 224 and the lower outer circumferential surface of the carrier 220 are generally cylindrical in shape, but the intermediate outer circumferential surfaces 232 and 234 have the shape of a polyhedron rather than a cylinder.

At this time, the outer peripheral surface of the interruption of the carrier 220 may have a polyhedron shape of various forms, for example, a tetrahedral shape or an octahedral shape as a whole. In other words, the planar cross-sectional shape (meaning the shape when viewed from the direction in which light is incident, which is used herein in the same sense below) of the outer circumferential surface of the carrier 220 is substantially a quadrilateral shape. Four surface parts 232 corresponding to an area where a bar-shaped magnet 310 is to be described later and four corner parts 234 corresponding to an area where the magnet 310 is not formed. Can be distinguished.

In addition, the lower outer circumferential surface of the carrier 220 may have a collar portion (flange 242) which protrudes outward to some extent in a form corresponding to the four surface portions 232 and the four corner portions 234 formed on the outer peripheral surface thereof. In this case, the driving coil 320 described later is mounted on the upper surface of the collar 242. In particular, a coil through part 244 having an upper end, a lower end, and an outer side is formed as an area corresponding to two corner parts of the four corner parts 234 constituting one area of the collar part 242, for example, the outer peripheral surface of the middle part. As such, the end of the driving coil 320 may extend to the outside. On the other hand, the peripheral area of the bottom of the carrier 220 forms a protrusion (boss, 246) configured to protrude downward, the protrusion 246 portion is a foreign matter prevention portion 740 formed on the upper surface of the base 700 to be described later ), The carrier 220 can be prevented from excessively falling.

Meanwhile, the magnet 310 and the driving coil 320 as the driving unit 300 for driving the lens module 200 are disposed along the outer circumferential surface of the carrier 220. According to a preferred aspect the magnet 310 is disposed along the top outer circumferential surface 224 having the cylindrical shape of the carrier 220, and the drive coil 320 is the suspended outer circumferential surface 232, 234 having the polyhedral shape of the carrier 220. Are placed along.

In particular, the magnet 310 according to the present embodiment is not a single shape having a cylindrical shape as in the related art, but is a magnet 310 having a bar shape as an example, as shown in FIG. May be composed of four independent bar-shaped magnets 310. In the case of disposing the shape of the magnet 310 in the form of four independent bars in the present invention, each of the magnets 310 extends in the optical axis direction in the form of an interview with the outer circumferential surface of the magnet 310. The inner circumferential surface of the shield 610 of 600 is disposed in a form corresponding to each.

Specifically, as will be described later, the shield case 600 has a tetragonal or octagonal flat-sectional shape, and substantially tetragonal tetrahedral or eighth tetrahedron having an upper and a lower end, as described later. It is a shape of a icosahedron. At this time, the shield 610 constituting the shield case 600 is a shape that extends in the optical axis direction while forming the side surface of the shield case 600, the inner peripheral surface of the shield 610 and the outer peripheral surface of the magnet 310 It is formed to be in contact. However, if the magnet 310 is configured in a hollow cylindrical shape, that is, an o-ring as in the prior art, the outer circumferential surface of the magnet 310 and the inner circumferential surface of the shielding portion 610 of the shield case 600 are not completely in contact with each other. Since a gap is formed, a problem may occur in that the flow of the magnetic field generated in the magnet 310 is not uniformly controlled by the shield 610. Thus, in the present invention, the magnet 310 is configured to have four independent bar shapes so that the outer circumferential surface of the magnet 310 may be in contact with the inner circumferential surface of the shield 610 having a quadrangular flat-section. .

As a result, when the magnet 310 is formed in the O-ring shape having a hollow portion as in the related art, the shield portion of the shield case 600 is not formed since the magnet 310 and the shield case 600 do not have a corresponding shape. 610 and the magnet 310 is divided into a region where a constant gap is formed. In this case, since the flow of magnetic flux generated from the magnet 310 is not uniformly controlled by the shielding portion 610, the flow of the magnetic field generated from the magnet 310 is also not uniform, so that the optical axis is not a driving force in the optical axis direction. The driving force may be generated in a direction that deviates from.

On the contrary, when the magnet 310 is formed in a quadrangular shape, preferably four independent bars, so as to correspond to the polygonal shape of the shield 610 forming the side surface of the shield case 600, the magnet 310 ) And the shield 610 may be uniformly contacted, so that the magnetic flux generated from the magnet 310 may be uniformly controlled in a predetermined direction through the shield 610. As a result, in the present invention, the inner circumferential surface of the shield case 600 is considered in consideration of the fact that the inner circumferential surface of the shield case 600 arranged in a shape extending in the optical axis direction along the outer circumferential surface of the magnet 310 has a quadrangular cross section. The shape of the magnet 310 is formed in a bar shape so that the magnetic field generated from the magnet 310 can be efficiently induced toward the.

In particular, the magnet 310 may be composed of four independent magnets each provided in an area corresponding to the surface portion of the side surface of the shield case 600 having a quadrangular cross-sectional shape. In this configuration, a region 314 in which the magnet 310 is not formed is formed between the respective magnets, and the magnet 310 is interposed between the respective portions 520 of the cover 510 which will be described later. ) Can be assembled stably.

According to the present invention, the magnet 310 closely contacted and disposed along the upper outer circumferential surface of the carrier 220 may use a permanent magnet used in a conventional voice coil motor (VCM) method, for example, a neodymium-based permanent magnet. For example, as illustrated in FIG. 5, the inner side may be disposed to have an S pole, and the outer side may have an N pole, or may be arranged in the reverse direction. As described above, as a method of arranging different polarities of the magnet 310 in a direction orthogonal to the optical axis, the single pole may be divided into an inside and an outside, or may be formed of a single magnet magnetized into a two pole.

In addition, while forming the driving unit 200 according to the present invention, the driving coil 320 disposed along the outer peripheral surfaces 232 and 234 having a polyhedral shape of the carrier 220 may have an outer side at approximately interruption of the carrier 220. It is seated on the upper surface of the collar portion (flange 242) protruding toward. Accordingly, the driving coil 320 according to the present invention may be configured to have a flat-cross section of a polygon including a quadrangular shape corresponding to the shape of the outer peripheral surface of the carrier 220 while forming a hollow portion. In one example, the driving coil 320 corresponds to the surface portion 322 extending relatively long corresponding to the surface portion 232 of the suspension outer peripheral surface of the carrier 220, and the corner portion 234 of the suspension outer peripheral surface of the carrier 220, It has a quadrilateral or octagonal flat cross-sectional shape in which corner portions (edge portions 324) are formed between the surface portions 322. The shape and arrangement of the driving coil 320 correspond to the shape of the shield 610 formed to face the outer circumferential surface of the driving coil 3200.

In addition, the driving coil 320 is configured to be electrically connected to an external power supply means (not shown) to receive a predetermined current from the external power supply means. To this end, a region of the collar portion 242 formed at approximately the middle height of the carrier 220 corresponding to the corner portion 234 of the carrier 220 stop is the coil through portion 244 whose top, bottom and outer sides are open. ) Accordingly, an end of the driving coil 320 may extend through the coil through part 244 to be electrically connected to an external power supply means (not shown) via the elastic means 410 and 420.

As a result, the magnetic field generated in the magnet 310 passes through the driving coil 320 disposed below the magnet 310, and is generated in the electric field applied to the driving coil 320 from the external power supply means and in the magnet 310. The electromagnetic force due to the interaction between the magnetic fields acts as a Lorentz force to drive the lens module 200 including the carrier 220 in the optical axis direction. In particular, according to the present embodiment as described later, in order to control the flow of magnetic flux generated in the magnet 310, the magnet 310 and the drive coil ( The magnetic flux may be controlled by the shield 610 of the shield case 600 which is formed to face the outer circumferential surface of the 320, which will be described later.

In addition, the elastic means to the upper and lower ends of the carrier 220 to fasten between the carrier 220 and the driving coil 320 repeating the up and down reciprocating motion along the optical axis and the magnet 320 is fixed in position 410 and 420 are provided. The elastic means 410 and 420 provide a restoring force to the carrier 220 moving in the optical axis direction to adjust the position of the carrier 220 and to supply current to the end of the driving coil 320. To this end, the elastic means 410 and 420 are coupled to the upper and lower surfaces of the movable part and the fixing part so as to elastically connect the carrier 220 and the driving coil 320 as the movable part and the magnet 310 as the fixing part. Is installed on.

Specifically, the elastic means 410, 420 according to the present invention is the first elastic body 410 is interposed to the upper end of the carrier 220 and the magnet 310, the lower surface of the carrier 220 and the upper surface of the base 700 It may be divided into a second elastic body 420 interposed therebetween. The first elastic body 410 and the second elastic body 420 are in the form of a plate-spring, preferably in the form of a wave-shaped plate-spring with a serpentine waveform along its circumferential surface. Can be alleviated and the resilience can be improved.

In addition, as described above, the end of the driving coil 320 may be formed of an elastic means 410 through a coil through part 244 formed in an area of the collar part 242 corresponding to the corner part 234 of the suspension outer peripheral surface of the carrier 220. It is electrically connected to an external power supply means through a method of connecting with 420. To this end, for example, a bottom of a portion of the second elastic body 420 forms a terminal 426 extending downward, and the terminal 426 is formed in the terminal groove 750 formed on the outer circumference of the side of the base 700. It is configured to be connected to an external power supply means (not shown) through. Through this method, the elastic means 410 and 420 control the position of the driving unit 200 by pressing the carrier 220 and at the same time adjust the degree of focusing on the subject by the driving unit 200.

Meanwhile, according to the present exemplary embodiment, the magnet 310 constituting the driving part 300 and the carrier 220 and the first elastic body 410 disposed on the upper surface of the magnet 310 may have a hollow part so as to be stably assembled. The tetrahedral cover 510 is disposed on the upper surface of the first elastic body 410. At this time, the edge portion (each portion, 520) is a shape extending downward compared to the surface portion of the cover 510, the outer surface of the first elastic body 410 and four independent bar shape to the bottom of the surface portion of the cover 510 A magnet 320 having a structure is disposed, and each portion 520 of the cover 510 is interposed with an empty area 314 between each magnet having a magnet shape having four independent bars, for example. Accordingly, the outer side of the first elastic body 410 and the magnet 310 can be assembled stably.

In addition, in the present invention, a shield case 600 having a shape surrounding the driving unit 200, the first elastic body 410, and the cover 510 is provided while providing the top shape of the lens actuator 100. The shield case 600 is provided with a predetermined hollow portion and forms a tetrahedron or an octahedron shape as a whole. The side surface of the tetrahedron form a shielding portion 610 extending downward in the optical axis direction. In other words, the flat-section of the shield case 600 is substantially quadrilateral. Accordingly, as shown in FIGS. 4 and 5, the shield case 600 covers the upper surface of the magnet 310-the first elastic body 410-the cover 510, and at the same time, the shield 610 on the side thereof. Through the magnet 310 has a shape that completely surrounds the outer circumferential surface of the driving coil 320.

 As described above, since the driving unit 200 that exerts the driving force is sealed from the outside by the shield case 600, a magnetic field generated from an external electronic component mounted on the mobile communication device equipped with the lens actuator 100 of the present invention. Is blocked by the shield case 600. Accordingly, since the magnetic field generated from the external electronic component does not affect the magnetic field generated by the driving unit 200 of the lens actuator 100, the focus of the lens actuator 100 due to the external magnetic field and the deterioration of image quality due to the magnetic field are caused. Can solve the problem.

In addition, the outer circumferential surface and the inner circumferential surface of the shield case 600 may have a quadrilateral shape or an octagonal shape. In particular, an area corresponding to the surface portion may form a shield portion 610 (see FIG. 5) extending downward in the optical axis direction. . Here, the upper inner circumferential surface of the shield 610 is in close contact with the outer circumferential surface of the magnet 310, and the lower inner circumferential surface of the shield 610 is opposite to the outer circumferential surface of the driving coil 320 disposed under the magnet 310. Is formed. Accordingly, the flow of the magnetic flux generated from the magnet 610 can be controlled by the shielding part 610 formed on the outside of the driving part 200 so that the desired driving force can be exhibited without forming a yoke separately. .

For this purpose, the shield case 600 including the shield 610 may be made of a metal material, and a conductive material such as iron, cold rolled steel, or nickel having excellent magnetic permeability. On the other hand, the outer circumferential surface of the shield case 600 includes a non-conductive material, for example, an insulating material such as a polymer insulating resin, so that the focal point in the lens actuator 100 of the present invention is caused by electromagnetic waves of other electronic components. Problems such as defects can be eliminated more efficiently.

In addition, according to the present exemplary embodiment, the base having a hollow portion to support the carrier 220 and the driving unit 200 while providing a bottom shape of the lens actuator 100 and having a substantially flat cross-section is formed in a quadrilateral form. 700 is formed.

At this time, each portion of the base 700 forms a coupling portion 710 extending upward, the coupling portion 710 is fitted into the coupling groove 620 formed on the outer peripheral surface of the shield case 600. In order to firmly connect the shield case 600 and the base 700, a groove 712 may be formed on the inner circumferential surface of the coupling part 710, for example, to which a bonding agent may be embedded. In addition, a boss 720 protrudes from the upper edge region of the base 700, and correspondingly, the fastening hole 424 is provided in the outer peripheral side edge region of the second elastic body 420, so that the second elastic body 420 is provided. The outer peripheral side of the base 700 is stably fixed.

Meanwhile, the hollow area of the base 700 is an area of the window window 730 in which an image of the subject passing through the lens module 200 is projected. The outer top of the area of the window window 730 is toward the subject side. The foreign matter prevention part 740 which protrudes so that the lower part of the carrier 220 may contact the protrusion (boss) 246 at the bottom of the carrier 220 is formed, and the application area 742 having a bonding agent applied to the periphery of the foreign matter prevention part 740 is formed. It is coming true. The foreign matter prevention part 740 may be formed at regular intervals with the application area 742 interposed therebetween, and may be formed in two, four, or eight symmetric positions. Accordingly, when the carrier 220 is disposed at the lowest position, the carrier 220 is contacted with the boss 246 (see FIG. 3) at the bottom of the carrier 220 to contact the upper surface of the foreign matter prevention unit 740. Can be supported by the base 700.

By the way, in the process of assembling or using the lens actuator 100 according to the present invention, a fine foreign matter may be generated into the optical system in which the subject is imaged. For example, when a foreign material flows into the upper surface of the base 150 via a gap between the outer circumferential surface of the carrier 220 and the inner circumferential surface of the driving unit 300, a window window in the center of the base 700, which is an area where the subject is imaged, Moving the foreign material to the area 730 may cause a focusing error, thereby degrading the image quality.

However, in the present invention, even if foreign matter flows into the upper surface of the base 700 via a gap between the outer circumferential surface of the carrier 220 and the inner circumferential surface of the driving part 300, the foreign matter prevention part 740 protrudes upwardly from the peripheral area. Movement to the window 730 is prevented or foreign matter can no longer move to the window 730 by the bonding agent formed in the application area 742 around the foreign matter prevention unit 740. Because of this, foreign matter cannot flow into the area of the window 730 forming the optical system of the base 700, and thus poor focusing control due to the foreign matter generated during the assembly and moving of the lens actuator 100 and the resulting image quality. The fall can be prevented. Preferably, the water barrier 740 may be configured in a form having a predetermined inclination toward the outside from the inner side where the window 730 is formed.

As a result, in the case of the present embodiment, since the shielding portion 610 disposed on the outer circumferential surface of the magnet 310 and the driving coil 320 controls the flow of magnetic flux, it is not necessary to form an independent yoke and at the same time, the conventional second elastic body There is also no need for a bottom cover to seat 410 into the base 600. Accordingly, the number of components can be reduced, thereby facilitating the assembly process, and in the case of the conventional VCM type lens actuator, the space occupied by the yoke and / or the lower cover has a limitation in reducing the size of the lens actuator. In order to obtain a driving force, a lens actuator having a size of 12 mm or less was impossible, whereas in the present invention, the size of the lens actuator can be reduced to a level of 8 mm. In addition, the shield case 600 can suppress the influence of the external electromagnetic wave to significantly reduce the error in the driving process.

Next, an operation between the magnet 310 constituting the lens actuator 100 according to the present embodiment, the driving coil 320, and the shield 610 of the shield case 600 will be described with reference to FIG. 6. FIG. 6 is an enlarged view of a region A of FIG. 5, wherein the direction of the magnetic field generated in the magnet 310 constituting the driving unit 300 according to the present embodiment, the direction of the electric field through the driving coil 320, and between them Shows the direction of electromagnetic force.

As illustrated, when a current is applied to the driving coil 320 while the driving coil 320 is wound clockwise along a lower outer circumferential surface of the carrier 220, the magnetic field generated by the magnet 310 is outside of the magnet 310. The flux of the magnetic flux is controlled by the shielding portion 610 of the shield case 600 of the ferromagnetic material formed in the. Therefore, as shown in the figure, the magnetic flux is formed toward the shielding portion 610 to the outside (right side), and according to Fleming's left hand law, a driving force is generated by Lorentz's force in the upward direction, that is, in the optical axis direction. The driving coil 320 disposed along the outer circumferential surface of the carrier 220 while being supported by the lens module 200 including the carrier 220 and the collar portion 242 about the middle of the carrier 220 by this driving force is provided. Can move in the direction of the optical axis.

In this case, in the magnetic circuit, when the direction of the magnetic flux is perpendicular to the winding direction of the drive coil 320, the current vector applied to the drive coil 320 and the magnet density vector generated from the magnet 310 are perpendicular to each other to drive the driving force. This is the maximum. At this time, when the induced magnetic field formed by the magnetic field and the applied current is repulsed or attracted to each other, the carrier 220 on which the driving coil 320 is wound and the lens unit 210 accommodated therein are applied to the optical axis direction by the force. It is movable.

In addition, the lens actuator 100 of the present invention includes an image sensor 820 mounted on a filter 810 fastened to the inner circumferential surface of the base 700 and a substrate 830 bonded by a bonding agent. That is, the hollow portion formed in the center of the base 700 is an area of the window window 730. In order to block a part of the incident light entering through the lens through the area 730 to control the amount of light, a filter 810, for example, For example, an IR filter is disposed between the carrier 220 and the image sensor 820.

Meanwhile, the image sensor 820 includes a plurality of pixel regions and electrodes that are input / output terminals of the pixel region, and the plurality of electrodes are electrically connected to electrodes of a printed circuit board (not shown) using, for example, wire bonding equipment. Connected. The image sensor 820 may be a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) type, and the image sensor 820 may have a wire W on the top surface of the substrate 830. It may be mounted in a bonding method or a flip-chip bonding method on the bottom surface of the substrate 830.

Subsequently, driving of the lens actuator 100 for a mobile communication device according to an embodiment of the present invention will be described. As described above, the lens actuator 100 of the present invention is a carrier by the interaction of the shield 610 extending long while forming the four sides of the magnet 310, the drive coil 320 and the shield case 600 Focusing is performed by repeatedly changing the position of the lens module 200 including the 220 along the optical axis. That is, the image of the subject passing through the center of the lens unit 210 is transferred to the image sensor 830 via the filter 820 is converted into an electrical signal, the image data converted into an electrical signal to the camera module body Focusing is transmitted to the controller, and the coil 220 wound around the outer circumferential surface of the carrier 220, the carrier 220, and the lens accommodated inside the carrier 220 in this process according to the direction of the applied current. Auto focusing is enabled by the unit 210 moving forward and backward along the optical axis.

Therefore, in order to focus the optical image on the subject with the image sensor, the lens module 200 including the carrier unit 220 and the lens unit 210 composed of a plurality of lenses assembled therein are moved in the optical axis direction to focus. You have to keep the distance. Specifically, auto focusing generates the autofocusing data by data-contrast the captured image, and adjusts the focus by positioning the lens at the largest position. If the subject is in focus, the shape of the subject is clear and the contrast is high. Since the distinction is clear, the autofocusing data is utilized.

Accordingly, when the user of the mobile communication device adopting the lens actuator 100 according to the present invention presses the shooting button, the image sensor is operated, so that the image of the subject located in front of the lens actuator 100 is hollow and the lens module 200. After passing through the filter 820 is converted into an electrical signal in the image sensor 830 is transmitted to a control unit (not shown) in the camera module. The controller determines that there is a focusing error in the lens actuator when the image signal of the subject transmitted to the image sensor 830 is blurred, so that both ends of the current supplying power for moving the lens module 200 in the optical axis direction are provided. It is applied to the drive coil 320 which is electrically connected to the.

Accordingly, as shown in FIG. 6, when a predetermined current is applied to the driving coil 320, a magnetic field is generated in the driving coil 320, and the magnetic flux generated from the magnet 310 is transferred to the shielding part 610. The flow is controlled in a constant direction, and the Lorentz force is generated by the repulsive force or the attractive force between the magnetic flux transmitted from the magnet 310 and the magnetic field formed in the drive coil 320. By the driving force, the lens module 200 including the carrier 220 and the driving coil 320 supported by the carrier 220 also move in the optical axis direction (see FIG. 7). In this method, the carrier 220 may be moved up and down on the optical axis to realize focusing for sharpening an image of a subject captured by the image sensor. If the current is supplied to the coil 320 in the opposite direction, the lens unit 200 including the carrier 220 may be moved downward.

On the other hand, other types of lens actuators are also possible. 8 is a cross-sectional view schematically showing a lens actuator according to another embodiment of the present invention, FIG. 9 is a view schematically showing the principle that the driving force is exerted according to the present embodiment, and FIG. 10 is according to the present embodiment. As a schematic cross-sectional view showing a state in which the lens actuator is driven, a detailed description of the same configuration as in the above-described embodiment will be omitted and will be briefly described based on a configuration that differs.

In the present embodiment, compared to the above-described embodiment, the yoke 330 made of a conductive material such as iron, cold rolled steel, or nickel having excellent magnetic transmittance is formed on the outer lower end of the magnet 310. It is formed along the direction. That is, the upper surface of the yoke 330 is formed to be interviewed with the outer bottom surface of the magnet 310, so that the inner circumferential surface of the yoke 330 is disposed opposite to the outer circumferential surface of the drive coil 320, the yoke 330 The outer circumferential surface of) is in contact with or opposed to the inner circumferential surface of the elongated shield 610 of the shield case 610. As a result, in the present embodiment, the yoke 330 is formed on the outer bottom surface of the magnet 310 in comparison with the above-described embodiment, so that the width of the driving coil 320 is narrowed. As such, when the width of the driving coil 320 is narrowed, there is a problem in exerting a desired driving force. Thus, the driving coil 320 extends in the optical axis direction in comparison with the above-described embodiment.

However, according to the present embodiment, in addition to the shield 610 having a form extending to the optical axis direction while forming the side surface of the shield case 600 in order to control the magnetic flux leaking in the upper and outer directions of the magnet 310 A yoke 330 is formed to control the flow of magnetic flux flowing to the bottom of the magnet 310. Because of the yoke 330 it is possible to more efficiently control the flow of the magnetic flux generated in the magnet 310 to flow only in the horizontal axis direction of the lens actuator 100 (see Fig. 9), so that the lens actuator 100 It can double the driving force. The yoke 330 according to the present embodiment has a larger hollow portion than the hollow portion of the driving coil 320, and corresponds to the surface portion and the corner portion corresponding to the shielding portion 320 of the driving coil 320 and the shield case 600. It is a polyhedron shape which has a part). In other words, the flat-sectional shape of yoke 330 is substantially quadrilateral.

In particular, according to the present embodiment, the inner circumferential surface of the yoke 330 is disposed to face the outer circumferential surface of the drive coil 320 at a predetermined interval. As described above, the yoke 330 and the driving coil 320 are disposed to face each other, and the magnet 310 does not exist at all between the driving coil 320 and the yoke 330. The magnetic flux to the 340 can be efficiently controlled. The magnetic flux flows in the magnet 310 by the magnet 310, the coil 320, the yoke 330, and the shield case 600 having such an arrangement so that only the radial direction of the lens actuator 100 flows. By controlling and concentrating the magnetic field generated by the magnet 310 to the driving coil 320, it is possible to finally improve the driving force of the lens actuator.

In the above, the present invention has been described in detail based on the preferred embodiments of the present invention, but the present invention is not limited thereto. Rather, those skilled in the art will be able to easily make various modifications and changes based on the embodiments described above. However, it will be more apparent through the appended claims that such variations and modifications fall within the scope of the present invention.

1 is an exploded perspective view schematically illustrating a coupling relationship between components constituting a lens actuator employing a VCM method, which is conventionally mounted in a mobile communication device.

2 is a schematic cross-sectional view of a conventional VCM lens actuator.

3 is an exploded perspective view schematically illustrating a coupling relationship between components constituting a lens actuator employing a VCM method of configuring a camera module mounted on a mobile communication device, according to an embodiment of the present invention.

4 is a perspective view schematically showing a state in which the lens actuator of the VCM method according to an embodiment of the present invention is coupled as a whole.

FIG. 5 is a cross-sectional view of the lens actuator of the VCM system according to an embodiment of the present invention, cut along the line V-V of FIG. 4.

6 is a view schematically showing a magnetic force direction, an electric field direction, and a driving force direction in the lens actuator according to the exemplary embodiment of the present invention.

FIG. 7 is a cross-sectional view schematically illustrating a state in which the lens actuator shown in FIG. 5 is driven along an optical axis.

8 is a schematic cross-sectional view of a lens actuator of the VCM method according to another embodiment of the present invention.

9 is a view schematically showing a magnetic force direction, an electric field direction and a driving force direction in the lens actuator according to another embodiment of the present invention.

FIG. 10 is a cross-sectional view schematically illustrating a state in which a lens actuator according to another embodiment of the present invention shown in FIG. 8 is driven along an optical axis.

Description of the main parts of the drawing

100: lens actuator 200: lens module (lens portion)

210: lens barrel 220: carrier

300: driving unit 310: magnet

320: driving coil 330: yoke

410: first elastic body 420: second elastic body

510: Cover 600: Shield Case

610: shield 700: base

Claims (10)

A lens module including a carrier accommodating a lens unit to photograph an object; A driving unit for moving the lens module along an optical axis direction by an interaction between a magnet disposed along an outer circumferential surface of the carrier and a driving coil; A polyhedral shape having a hollow portion, the shield case covering a top surface of the magnet and forming a shielding portion extending along an outer circumferential surface of the magnet and the driving coil in an optical axis direction; A base supporting a bottom surface of the carrier and the drive unit Lens actuator for a mobile device comprising a. The method of claim 1, wherein the upper end of the carrier is cylindrical, the interruption of the carrier has a polygonal flat cross-section, the magnet is a bar shape formed along the upper outer peripheral surface of the carrier Lens actuators for mobile devices. 3. The lens actuator of claim 2, wherein the drive coil has a polygonal flat cross-sectional shape to be formed along an outer circumferential surface of the carrier suspension having a polygonal flat cross-section. 4. The lens actuator of claim 3, wherein the suspension of the carrier and the drive coil have a flat cross-section of a quadrilateral. The mobile device of claim 1, further comprising a yoke interposed between an outer circumferential surface of the driving coil and an inner circumferential surface of the shielding portion of the shield case and extending along an optical axis direction from a bottom surface of the magnet. Lens actuator for instruments. The lens actuator according to any one of claims 1 to 3, further comprising elastic means in contact with the top and bottom of the carrier, respectively. The lens actuator of claim 6, wherein the elastic means comprises a first elastic body pressing the upper end of the carrier and a second elastic body pressing the lower end of the carrier. The lens actuator of claim 7, further comprising a cover disposed on an upper end of the first elastic body to press the upper end of the carrier. The method of claim 8, wherein the magnet is a plurality of bar (bar) shape is formed along the upper outer peripheral surface of the carrier, each portion of the cover is extended downward and is interposed between each magnet in the form of the plurality of bars Lens actuators for mobile devices. The mobile device according to claim 1, wherein the base has a quadrilateral flat-section having a window formed at the center thereof, and each corner is extended upward and coupled to the outer circumferential surface of each section of the shield case. Lens Actuator.

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