KR20110058581A - Lens actuator for image pickup apparatus - Google Patents

Abstract

PURPOSE: A lens actuator for an image pickup device is provided to suppress a change of a location or modification in each member by blocking an inflow of foreign materials generated in an assembling and driving process. CONSTITUTION: An actuator(100) for image pickup device comprises a lens part(110), a driving part(140), and a casing part. The lens part includes a lens barrel(120) for receiving lenses and a carrier(130) coupled with an outer circumference of the lens barrel and is moved in an optical axis direction. The driving part includes a magnet(142) arranged along an outer circumference of the carrier, a first yoke(144) arranged along the outer circumference of the carrier in a lower portion of the magnet, a second yoke(146) arranged apart from the first yoke, and a coil(148) arranged between the first and second yokes to be would around the outer circumference of the carrier. The driving part moves the lens part along the optical axis direction. The casing part is coupled to surround the lens part and the driving part.

Description

Lens actuator for image pickup device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera lens assembly, and more particularly, to a lens actuator for image capturing, which is mounted on a small image capturing apparatus to enable auto focus adjustment.

In general, a camera is a device capable of photographing a subject through a lens, and includes a plurality of lenses for focusing and zooming to adjust focus by adjusting a relative distance.

Recently, a digital image pickup device (Image Pickup Apparatus) has been widely used in mobile communication devices such as digital cameras, mobile phones. Such a digital image pickup device is equipped with various lens actuators for zooming or auto focusing.

On the other hand, the camera module mounted on the miniaturized mobile communication device is equipped with a focusing function to sharply form the subject in the image sensor by adjusting the distance between the plurality of lenses and the image sensor or changing the curvature of the lens in order to clearly see the subject. Should be. In order to realize such a focusing function, a manual, a step motor, a piezoelectric element, a voice coil motor (VCM) and the like should be provided. Here, the voice coil motor (VCM) is a device that plays a role of precisely focusing by using the induction magnetic force of the permanent magnet and the coil, and is also called a voice coil actuator (VCA).

As shown in FIG. 1, a general VCM-type lens actuator 10 includes a lens barrel 20 having a plurality of focusing lenses L, a carrier 30 accommodating the lens barrel 20, A magnet 40 disposed along the outer periphery of the carrier 30, a yoke 50 for controlling the magnetic force of the magnet 40, and a coil 60 disposed around the lower end of the carrier 30. It includes.

In addition, the base 70 is coupled along the lower portion of the carrier 30, the cover (70) to fix the carrier 30, the magnet 40 and the yoke 50 on the upper portion of the base (70) 80) is assembled. The carrier 30 has an upper spring 32 and a lower spring 34 fastened to upper and lower portions to control the driving force to a certain limit.

The lens actuator 10 of the VCM method is disposed to face the magnet 40 generating the magnetic force and the coil 60 to which the current is applied, so that the coil 60 is mutually generated within the magnetic force generated by the magnet 40. The carrier 30 is driven by the Lorentz force generated in the vertical direction of the current and the magnetic field, that is, the optical axis direction, by the induced magnetic force caused by the action.

However, in the lens actuator 10 of the VCM method, the cover 80 simply contacts the upper portion of the base 70, and the cover 80 may be separated from the base 70 by an external impact. As a solution to this problem, the base 70 and the cover 80 were fixed by using a separate fastening means. However, even if the fastening means is fixed between the base 70 and the cover 80, the possibility of the base 70 and the cover 80 being separated cannot be excluded, while the lens L is inserted into the carrier 30. As the lens actuator 10 is rotated in a direction perpendicular to the optical axis when assembling, the driving unit is not arranged at the correct position, thereby failing to achieve stable focusing.

On the other hand, the lens actuator 10 of the VCM method does not always have a fixed position, but its positional relationship may be changed in the process of using a mobile communication device. Although the direction of the subject is shown in the upper direction in FIG. 1, on the contrary, when using the mobile communication device in a form in which the subject is positioned at the bottom of the lens actuator 10 or by the so-called 'posture car' for the resilience of the elastic body. When the position of the lens actuator 10 is changed, the driving unit disposed along the periphery of the carrier 30 as well as the carrier 30 due to gravity is sag, so that the spring 32 also receives pressure from the carrier 30 and the driving unit. Deformation without winning makes it difficult to achieve normal focusing control by the spring 32.

On the other hand, foreign matters such as fine dust may flow into the gaps between the assembly parts during the assembly process or the process of driving the lens actuator 10, and the foreign matters may be coupled to the upper surface of the image sensor coupled to the bottom of the lens actuator 10. Moving to may cause errors in imaging of the subject. In addition, the mobile communication device in which the lens actuator 10 is mounted includes various electromagnetic components, and the lens actuator 10 may be affected by the external electromagnetic force generated by the electromagnetic components mounted on the outside of the camera module. It may cause a disturbance in driving.

On the other hand, with respect to a hybrid type lens actuator, Korean Patent Laid-Open Publication No. 2008-35601 (hereinafter referred to as Prior Art 1) discloses an assembling method of an imaging device and an imaging device, and Japanese Patent Laid-Open Publication No. 2007-108539 ( Hereinafter, an image pickup device is referred to as Prior Art 2 and a lens driving apparatus is disclosed in Japanese Patent Laid-Open No. 2007-298551 (hereinafter referred to as Prior Art 3).

Hybrid type lens actuators such as the prior arts 1, 2, and 3 have advantages in that they can be configured compactly by reducing the size, but the driving force is relatively lower than the lens actuator 10 as shown in FIG. It has the disadvantage of not being free to change. In addition, there was a problem in that foreign matter such as fine dust flows into the gap between the assembly parts during the assembly process or the driving of the lens actuator.

Disclosure of Invention An object of the present invention is to provide a lens actuator for an image capturing apparatus, which is devised to solve the above-described problems and enables stable focusing while increasing driving force.

Another object of the present invention is to provide a lens actuator for an image pickup apparatus that can block foreign substances generated during assembly and driving.

Still another object of the present invention is to provide a lens actuator for an image pickup apparatus capable of suppressing positional change or deformation of each member constituting the lens actuator in an assembly process or a test process.

In order to achieve the above object, the present invention provides a lens barrel which accommodates a lens and a lens coupled to the outer periphery of the lens barrel and movable in the optical axis direction, and a magnet disposed along the outer periphery of the carrier; A first yoke disposed along the outer periphery of the carrier and a second yoke disposed between the first yoke and the first and second yokes disposed at a predetermined distance from the bottom of the magnet and along the outer periphery of the carrier. And a driving unit having a wound coil to move the lens unit along the optical axis direction, and a casing unit coupled to surround the lens unit and the driving unit.

The present invention includes a lens barrel for accommodating a lens and a lens unit movable in an optical axis direction with a carrier coupled to an outer periphery of the lens barrel, a first yoke and the first yoke disposed along an outer periphery of the carrier. A magnet disposed along an outer periphery of the second yoke and a coil disposed between the second yoke and the first and second yokes disposed at a predetermined distance from the first yoke and wound along the outer periphery of the carrier. And a driving unit for moving the lens unit along the optical axis direction, and a casing unit coupled to surround the lens unit and the driving unit.

The magnet is arranged to have an N pole inside and an S pole outside on the basis of the cross section. Here, the upper portion of the first yoke is disposed to contact the N pole of the magnet, and the second yoke is disposed to contact the S pole of the magnet.

A magnetic fluid is provided along an upper portion where the first yoke and the coil intersect to block foreign substances from entering the lens unit.

The casing means includes a cover coupled to an outer periphery of the driving unit, a base supporting a lower end of the lens unit, and a shielding cover coupled to an upper portion of the cover.

The base is provided with a foreign matter blocking unit for blocking foreign substances introduced between the carrier and the driving unit.

It further comprises an elastic means disposed between the lens portion and the casing means for imparting a restoring force to the lens portion. The elastic means includes a first elastic body disposed below the carrier and formed with a corrugated groove along a circumferential surface, and a corrugated groove formed on the carrier and formed with a second elastic body along a circumferential surface.

A guide ring for preventing rotation is provided on the second elastic body and the casing means.

According to the lens actuator for an image capturing apparatus according to the present invention, the driving force can be increased by efficiently controlling the magnetic flux while suppressing leakage flux by optimally arranging the first and second yokes on the outer periphery of the carrier with respect to the magnet.

In addition, a magnetic fluid is provided along an upper portion where the first yoke and the coil cross the driving unit, and a foreign matter blocking unit is formed in the base to block foreign substances generated during the assembly and driving process from flowing between the carrier and the driving unit. As a result, it is possible to block foreign matter from entering the optical system for capturing the subject, thereby preventing a focusing error in the capturing process of the subject.

In addition, by allowing the lens unit and the driving unit to be assembled at a stable position through the casing means, it is possible to prevent the case member from being separated during a test process or an external impact, so that stable focusing can be realized, and a focusing error can be suppressed so that automatic Auto Focusing can be implemented.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The lens actuator of the first and second embodiments of the present invention adopts a voice-coil motor (VCM) method, and increases driving force generated in the driving unit and prevents foreign substances from flowing in from the outside, It has technical characteristics to prevent deformation while implementing stable focusing through stability.

First Embodiment

2 is an exploded perspective view of a lens actuator according to a first embodiment of the present invention, Figure 3 is a perspective view of a lens actuator according to a first embodiment of the present invention, Figure 4 is a cross-sectional view taken along the line AA of Figure 3 to be.

As shown in FIGS. 2 to 4, the lens actuator 100 according to the first exemplary embodiment of the present invention includes a lens unit 110 corresponding to a movable part moving in the optical axis direction in the imaging process of the subject, and the lens The driving unit 140 is disposed along the outer periphery of the unit 110 to generate a driving force, and a casing unit coupled to surround the lens unit 110 and the driving unit 140. In addition, the driving unit 140 further includes an elastic means for controlling the driving force. The casing means includes an upper cover 150, a lower cover 160, and a base 170, and the elastic means includes a first elastic body 180 and a second elastic body 182.

The lens unit 110 includes a lens barrel 120 accommodating the lens L and a carrier 130 coupled to an outer periphery of the lens barrel 120. Here, the lens unit 110 implements focusing by changing the focal length of the subject while the lens barrel 120 is moved as the carrier 130 is moved in the optical axis direction by the driving unit 140. have.

The lens barrel 120 is configured to accommodate one or more lenses L therein, and a thread 122 is formed on an outer circumference thereof to screw the thread 132 formed on an inner circumference of the carrier 130. .

The carrier 130 has a hollow cylindrical structure, and a thread 132 is formed at an inner circumference thereof to be coupled to the thread 132 of the lens barrel 120. The carrier 130 has the driving unit 140 disposed along an outer circumference thereof, and is accommodated in the casing means so as to be movable up and down. The carrier 130 has a flange 134 is formed at the bottom, the locking end 136 is extended to the top of the flange 134 to the outside. Here, the flange 134 is to be seated in the coil 148 of the drive unit 140 to be described later.

The driving unit 140 includes a magnet 142 disposed along the outer circumference of the carrier 130, and a first yoke 144 disposed along the outer circumference of the carrier 130 below the magnet 142. And a second yoke 146 disposed at a predetermined distance from the first yoke 144, and a coil disposed between the first and second yokes 144 and 146 and wound along an outer periphery of the carrier 130. It consists of 148. In this case, the driving unit 140 is the magnet 142 is fixed, while the coil 148 is a coil starting type that changes its position as the lens unit 110 moves.

As shown in FIGS. 2 and 4, the magnet 142 has a ring-like structure and is arranged to have an N pole inside and an S pole outside on the basis of the cross section. Of course, the magnet 142 may be arranged to have an S pole inside and an N pole outside. Here, the magnet 142 is arranged in a different polarity in the horizontal direction, it can be configured using a method of dividing the single pole into the inside and the outside, or may be composed of a single magnet magnetized in two poles.

The first and second yokes 144 and 146 are made of a conductive material to control the flow of magnetic force generated in the magnet 142, that is, the magnetic flux, and are arranged around the magnet 142.

As shown in FIG. 4, the first yoke 144 has a ring-shaped structure surrounding an outer periphery of the carrier 130. The upper end of the first yoke 144 is disposed to face the coil 148 while the upper end thereof contacts the N pole of the magnet 142. Here, the lower part of the first yoke 144 may be disposed to face the coil 148 to efficiently control the magnetic flux generated by the magnet 142.

As shown in FIG. 4, the second yoke 146 has a ring-shaped structure having a larger diameter than the first yoke 144 and is spaced apart from the first yoke 144 at a predetermined distance. In addition, the second yoke 146 is disposed such that the lower end thereof faces the coil 148 while the upper end thereof contacts the S pole of the magnet 142. Here, the second yoke 146 may efficiently control the magnetic flux while suppressing the leakage magnetic flux from the magnet 142.

Due to the arrangement of the first and second yokes 144 and 146, the diameter of the lens actuator 100 may be reduced by disposing the first and second yokes 144 and 146 at the lower end of the magnet 142. In addition, the magnetic flux in the magnet 142 is controlled to flow only in the radial direction of the lens actuator 100, and the magnetic force generated in the magnet 142 is concentrated on the coil 148, thereby driving the driving force of the lens actuator 100. Can improve.

The upper end of the coil 148 is spaced apart from the lower end of the magnet 142 by a predetermined interval, and is disposed between the first and second yokes 144 and 146. Here, the coil 148 serves as a movable part which repeats the up and down reciprocating motion along the optical axis together with the lens unit 110 to adjust the focusing on the subject photographed by being seated on the flange 134 of the carrier 130. . That is, the coil 148 is electrically connected to an external power source to receive a current to generate a magnetic field in the magnet 142, and at the same time to interact with the magnetic field to generate Lorentz force or driving force by electromagnetic force.

On the other hand, the driving unit 140 is provided with a magnetic fluid (MF; Magnetic Fluid) along the upper portion where the first yoke 144 and the coil 148 intersect. The magnetic fluid MF serves to block foreign matter from flowing between the lens unit 110, that is, the carrier 130 and the driving unit 140. This is formed outside the optical system in which the subject is actually photographed, thereby preventing fine foreign matter, that is, particles, from entering the optical system for imaging the subject.

As shown in FIG. 3, the casing means supports an upper cover 150 and a lower cover 160, a lower portion of the carrier 130, and the lower cover 160, which form an outer shape of the lens actuator 100. The base 170 is included. The shield cover 190 further includes a shield cover 190 coupled to the upper cover 150.

As shown in FIG. 2, the upper cover 150 has a quadrangular plate-like structure in which a hollow portion is formed in the center to accommodate the carrier 130, and coupling portions 152 are extended to corner portions to be described later. The guide ring 184, the second elastic body 182 and the driving unit 140 is coupled to the base 170 while receiving in sequence from above. A coupling groove 154 is formed in the central longitudinal direction of the coupling portion 152, and a guide groove 156 is formed to face the coupling groove 154. Here, the hook 176 of the base 170, which will be described later, is coupled to the coupling groove 154, and the engaging end 184a of the guide ring 184 is coupled to the guide groove 156.

As shown in FIG. 2, the lower cover 160 has a quadrangular plate-like structure, and a hollow portion is formed at the center thereof to accommodate the lens unit 110, and a hook through hole 162 and a through hole at a corner thereof. 164 and fastening holes 166 are formed to couple the upper cover 150 and the base 170 to each other. In addition, the lower cover 160 is configured to allow the upper second yoke 146 to be seated thereon, and pressurizes the outer circumference of the first elastic body 180 to be described later with the base 170 firmly fixed. Here, the lower cover 160 is stably assembled around the inner portion of the upper cover 150 so that the magnet 142 and the first and second yokes 144 and 146 are not separated.

Since the upper cover 150 and the lower cover 160 are firmly fixed through a plurality of fastening means, the upper cover 150 and the lower cover 160 are not separated in the external impact or the test process, thereby enabling stable focusing.

The base 170 has a quadrangular plate-like structure, and a hollow portion is formed at the center thereof to support lower ends of the carrier 130 and the lower cover 160, and the window active window is large enough to accommodate the carrier 130. An image of the subject is transferred to a filter (not shown) or an image sensor (not shown) by forming a (not shown).

And, as shown in Figure 2 and 6, the base 170, the support end 172 is formed to support the lower portion of the carrier 130, foreign matter blocking along the periphery of the support end 172 The portion 174 is formed, and the hooks 176 are extended to the corner portions, respectively, to be coupled to the upper cover 150 and the lower cover 160.

The foreign matter blocking unit 174 serves to block foreign substances introduced between the carrier 130 and the driving unit 140 in the process of assembling the lens actuator 100 or the image capturing process by applying an adhesive.

As shown in FIGS. 2 and 3, the shielding cover 190 has a quadrangular plate-like structure, and a fixed end is formed at the corner thereof to be coupled to the coupling groove 154 of the upper cover 150. Here, the shielding cover 190 serves to absorb the shock and prevent the inflow of foreign substances by correcting the gap between the components constituting the lens actuator 100.

On the other hand, the lens actuator 100 further includes an elastic means for providing a restoring force for the drive unit 140. That is, the elastic means supplies current to both ends of the coil 148, and determines the relative position of the lens unit 110 by applying a restoring force to the lens unit 110 to move in the optical axis direction.

The elastic means includes a first elastic body 180 disposed below the carrier 130 and a second elastic body 182 disposed above the carrier 130. Here, the first and second elastic bodies 180 and 182 are divided into an inner circumferential portion and an outer circumferential portion, and a locking portion is formed mainly on the outer circumferential portion, so that the carrier 130, the driving unit 140, the upper cover 150, and the lower cover 160 are located. It is fixed to be in close contact. Accordingly, the first and second elastic bodies 180 and 182 are elastic in accordance with the movement of the carrier 130 while the outer circumference is fixed by the driving unit 140, the upper cover 150, and the lower cover 160. To be variable.

The first elastic member 180 has a leaf spring structure and is disposed between the carrier 130 and the lower cover 160, and a corrugated groove 180a is formed along a circumferential surface thereof. Here, the corrugated groove 180a serves to alleviate external shock and improve restoring force. In addition, each of the first elastic bodies 180 has through holes 180b formed at corners thereof, and a feed terminal 180c is provided at one side thereof to be connected to an external power source.

The second elastic member 182 has a leaf spring structure and is disposed between the upper end of the magnet 142 and the upper end of the carrier 130 and the upper cover 150, and the corrugated groove 182a along the circumferential surface thereof. Is formed. Here, the corrugated groove 182a serves to mitigate external shock and improve restoring force.

On the other hand, a guide ring 184 of a magnetic material is disposed above the second elastic body 182. As shown in FIG. 5, the guide ring 184 has the same inner diameter as the second elastic body 182 and has a plurality of engaging ends 184a formed on an outer circumferential surface thereof to guide the grooves of the upper cover 150. 156). Here, the guide ring 184 is coupled to the guide groove 156 of the upper cover 150 to couple the lens barrel 120 to the carrier 130, the driving unit 140 or the first, second elastic body ( 180, 182 serves as a stopper to prevent the rotation in the direction perpendicular to the optical axis.

A driving process of the lens actuator 100 according to the first embodiment of the present invention will be described. The lens actuator 100 is a lens barrel 120 and a carrier 130, which is the lens unit 110, according to the interaction between the magnet 142, the first and second yokes 144 and 146, and the coil 148, which are the driving unit 140. Focusing is performed to change the position of h).

That is, the image of the subject passing through the center of the lens barrel 120 is transferred to an image sensor (not shown) through a filter (not shown) and converted into an electrical signal, and the image data converted into an electrical signal is transferred to the camera body. The control unit (not shown) is transmitted to perform focusing, and the carrier 130, the lens barrel 120, and the coil 148 move forward and backward along the optical axis in accordance with the direction of the applied current. ) Is performed.

 Here, in order to focus the optical image on the subject with an image sensor (not shown), the lens unit 110 in which the lens barrel 120 is assembled is moved in the optical axis direction to adjust the focal length. When a predetermined current is applied to the coil 148, a magnetic field is generated in the coil 148 to generate Lorentz force, that is, driving force, by repulsive force or attraction force with the magnetic flux transmitted from the magnet 142. By the driving force, the carrier 130, the lens barrel 120, and the coil 148 move in the optical axis direction. When the carrier 130 continues to move upward in the optical axis direction, the locking end 136 is moved to the first yoke. In contact with the bottom of 144, its movement is limited.

According to the configuration according to the first embodiment of the present invention, the diameter of the lens actuator 100 can be reduced compared to the conventional by arranging the first and second yokes 144 and 146 at the lower end of the magnet 142 in the driving unit 140. . In addition, the magnetic flux in the magnet 142 is controlled to flow only in the radial direction of the lens actuator 100, and the magnetic force generated in the magnet 142 is concentrated on the coil 148, thereby driving the driving force of the lens actuator 100. Can improve.

Second Embodiment

FIG. 7 is an exploded perspective view of a lens actuator according to a second embodiment of the present invention, and FIG. 8 is a longitudinal sectional view of the lens actuator according to the second embodiment of the present invention.

As shown in FIGS. 7 to 8, the lens actuator 200 according to the second embodiment of the present invention includes a lens unit 210 corresponding to a movable part moving in the optical axis direction in the imaging process of the subject, and the lens A driving unit 240 disposed along the outer periphery of the unit 210 to generate a driving force, and a casing means coupled to surround the lens unit 210 and the driving unit 240. In addition, the driving unit 240 further includes an elastic means for controlling the driving force. The casing means includes an upper cover 250, a lower cover 260, and a base 270, and the elastic means includes a first elastic body 280 and a second elastic body 282.

Here, in the lens actuator 200 according to the second embodiment, the lens unit 210 having the lens barrel 220 and the carrier 230, the casing means and the elastic means are the lens actuator actuator according to the first embodiment ( Since the lens unit 110, the casing means and the elastic means are substantially the same at 100, the description thereof is omitted.

The driving unit 240 includes a magnet 242 disposed along the outer periphery of the carrier 230, and a first yoke 244 disposed along the outer periphery of the carrier 230 below the magnet 242. And a second yoke 246 disposed at a predetermined distance from the first yoke 244, and a coil disposed between the first and second yokes 244 and 246 and wound along an outer periphery of the carrier 230. It consists of 248. In this case, the driving unit 240 is the magnet 242 is fixed, while the coil 248 is a coil starting type that changes its position as the lens unit 210 moves.

As shown in FIGS. 7 and 8, the magnet 242 has a ring-like structure and is arranged to have an N pole inside and an S pole outside on the basis of the cross section. Of course, the magnet 242 may be arranged to have an S pole inside and an N pole outside. Here, the magnets 242 are arranged with different polarities in the horizontal direction, and may be formed using a method of dividing the single pole into the inside and the outside, or may be configured as a single magnet magnetized by two poles.

The first and second yokes 244 and 246 are made of a conductive material to control the flow of the magnetic force generated in the magnet 242, that is, the magnetic flux, and are arranged around the magnet 242.

As illustrated in FIG. 8, the first yoke 244 has a ring-shaped structure surrounding an outer periphery of the carrier 230. The first yoke 244 is disposed such that its upper outer diameter is in contact with the N pole of the magnet 242, and its lower portion is disposed opposite to the coil 248. Here, the first yoke 244 is formed to surround the inner periphery of the magnet 242 can reduce the leakage of the magnetic flux as compared to the first yoke 144 of the drive unit 140 in the first embodiment.

As shown in FIG. 8, the second yoke 246 has a ring-shaped structure having a larger diameter than the first yoke 244, and is spaced apart from the first yoke 244 at a predetermined distance. In addition, the second yoke 246 is disposed so that the lower end thereof faces the coil 248 while the upper end thereof contacts the S pole of the magnet 242. Here, the second yoke 246 may efficiently control the magnetic flux while suppressing the leakage magnetic flux from the magnet 242.

Due to the arrangement of the first and second yokes 244 and 246, the magnetic flux flows in the magnet 242 only in the radial direction of the lens actuator 200, and the magnetic field generated in the magnet 242 is the coil 248. By focusing on, the driving force of the lens actuator 200 can be improved.

An upper end of the coil 248 is spaced apart from the lower end of the magnet 242 by a predetermined interval, and is disposed between the first and second yokes 244 and 246. Here, the coil 248 serves as a movable part which repeats the vertical reciprocating movement along the optical axis together with the lens unit 110 to adjust the focusing on the subject to be photographed seated on the flange 234 of the carrier 230. . That is, the coil 248 is electrically connected to an external power source to receive a current to generate a magnetic field in the magnet 242, and at the same time to interact with the magnetic field to generate Lorentz force or driving force by electromagnetic force.

On the other hand, the drive unit 240 is provided with a magnetic fluid (MF; Magnetic Fluid) along the upper portion where the first yoke 244 and the coil 248 intersect. The magnetic fluid MF serves to block foreign matter from flowing between the lens unit 210, that is, the carrier 230 and the driving unit 240. This is formed outside the optical system in which the subject is actually photographed, thereby preventing fine foreign matter, that is, particles, from entering the optical system for imaging the subject.

According to the configuration according to the second embodiment of the present invention, the first yoke 244 in the configuration unit 240 is formed to surround the inner periphery of the magnet 242 to reduce the magnetic flux leakage and to efficiently control the magnetic flux, By controlling the flow of magnetic flux in the magnet 242 to flow only in the radial direction of the lens actuator 200 and by concentrating the magnetic field generated in the magnet 242 to the coil 248, the driving force of the lens actuator 200 can be improved. Can be.

As described above, the present invention has been described based on the preferred embodiments, but is not limited to the specific embodiments, it can be changed within the scope described within the claims by those skilled in the art.

1 is a cross-sectional view of a typical lens actuator;

2 is an exploded perspective view of a lens actuator according to a first embodiment of the present invention;

3 is a perspective view of a lens actuator according to a first embodiment of the present invention;

4 is a cross-sectional view taken along the line A-A of FIG.

5 is a plan view of a lens actuator according to a first embodiment of the present invention;

6 is a cross-sectional view taken along the line B-B of FIG.

7 is an exploded perspective view of a lens actuator according to a second embodiment of the present invention;

8 is a longitudinal sectional view of the lens actuator according to the second embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

100,200: lens actuator 110,210: lens unit

120,220: Lens barrel 130,230: Carrier

140,240 drive unit 142,242 magnet

144,244: First York 146,246: Second York

148,248 coil 150,250 top cover

160,260: Lower cover 170,270: Base

180,280: first elastic body 182,282: second elastic body

184,284: Guide ring 190,290: Shield cover

L: Lens MF: Magnetic Fluid

Claims (9)

A lens barrel configured to move in the optical axis direction, the lens barrel including a lens barrel and a carrier coupled to an outer periphery of the lens barrel; A magnet disposed along the outer periphery of the carrier, a first yoke disposed along the outer periphery of the carrier under the magnet, a second yoke disposed at a predetermined distance from the first yoke, and the first A driving unit disposed between two yokes and having a coil wound along an outer periphery of the carrier to move the lens unit along an optical axis direction; And Casing means coupled to surround the lens unit and the drive unit; Lens actuator for an image pickup device comprising a. A lens barrel configured to move in an optical axis direction with a lens barrel accommodating a lens and a carrier coupled to an outer periphery of the lens barrel; A first yoke disposed along the outer periphery of the carrier, a magnet disposed along the outer periphery of the first yoke, a second yoke and the first yoke disposed below the magnet at a predetermined distance from the first yoke; A driving unit disposed between two yokes and having a coil wound along an outer periphery of the carrier to move the lens unit along an optical axis direction; And Casing means coupled to surround the lens unit and the drive unit; Lens actuator for an image pickup device comprising a. The method according to claim 1 or 2, The magnet is a lens actuator for image pickup, characterized in that arranged on the basis of the cross section having an N pole inside and an S pole outside. The method of claim 3, wherein The first yoke is disposed so that the upper portion is in contact with the N pole of the magnet, And the second yoke is disposed such that an upper portion thereof contacts the S pole of the magnet. The method according to claim 1 or 2, A magnetic actuator is provided along an upper portion where the first yoke and the coil intersect to block foreign substances from flowing into the lens unit. The method according to claim 1 or 2, The casing means includes a cover coupled to the outer periphery of the driving unit, a base supporting the lower end of the lens unit, and a shielding cover coupled to an upper portion of the cover. The method of claim 6, And the base is provided with a foreign matter blocking unit for blocking foreign substances introduced between the carrier and the driving unit. The method according to claim 1 or 2, An elastic means disposed between the lens portion and the casing means to impart a restoring force to the lens portion, The elastic means is an image pickup device, characterized in that the first elastic body disposed in the lower portion of the carrier and formed along the circumferential surface, and the corrugated groove formed on the carrier and formed along the circumferential surface of the carrier Lens Actuator. The method of claim 8, Lens actuator for an image pickup device, characterized in that the anti-rotation guide ring is provided on the second elastic body and the casing means.

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