Actuator for camera

Abstract

The present invention relates to an actuator for a camera including a Halbach magnet and a yoke formed of a ferromagnetic material. The actuator for a camera of the present invention comprises: a housing; a first lens assembly and a second lens assembly configured to move along an optical axis direction in the housing; a first M yoke and a second M yoke fixed to the first lens assembly and the second lens assembly, respectively; a first magnet part and a second magnet part attached to flat plates of the first M yoke and the second M yoke, respectively; and a first coil part and a second coil part fixed to the housing so as to drive the first magnet part and the second magnet part, respectively, wherein the first magnet part and the second magnet part may have a plurality of magnets arranged in a Halbach array, and magnetic flux directions thereof may be perpendicular to the optical axis. The actuator for a camera according to the present invention can more strongly drive the lens assembly with an improved driving force.

Description

Actuator for camera

[0001] The present invention relates to a camera actuator with improved driving force.

[0002] The actuator used in the camera module is a driving device that moves the lens to the optimal focus position to achieve sharp image quality by magnifying or reducing the subject during shooting.

[0003] Voice coil motor (VCM) actuators utilize coils and magnets to implement lens movement. In the VCM method, the magnetic force (magnetic flux density) of the magnet determines the driving force of the actuator; therefore, a magnet with strong magnetic force is an essential and important component.

[0004] The actuator of the camera module performs focusing operations to enlarge or reduce the subject and focus by varying the position of the lens assembly to adjust the distance between the image sensor and the lens.

[0005] The coil portion is mounted in the housing of the actuator, and the magnet assembly containing the magnet is installed facing the coil portion.

[0006] When current flows through a coil located within a magnetic field formed by a magnet, a Lorentz force is generated, and the magnet assembly is driven.

[0007] As the magnitude of the magnetic field radiated in the direction of the coil increases, the driving force of the magnet assembly increases; consequently, the driving force of the lens assembly fixed to the magnet assembly also increases. In this case, the magnetic field radiated in the opposite direction to the coil may cause interference with the operation of other magnets or other electronic components.

[0008] As such, appropriate amplification or shielding according to the radiation direction of the magnetic field of the magnet assembly is important for realizing the performance of the actuator.

[0009] The driving force (F) applied to the magnet assembly is obtained as follows.

[0010] F (driving force) = B (magnetic force) × I (current) × L (coil length)

[0011] That is, the driving force (F) is proportional to the magnitude (I) of the current applied to the coil section, the length (L) of the coil section, and the magnetic force (B) of the magnet assembly.

[0012] In line with the recent increase in performance requirements for camera modules, lens assemblies may include multiple lens assemblies, and as the size of image sensors increases, actuators require greater driving force.

[0013] Increasing the current applied to the coil increases power consumption, and increasing the length of the coil increases the size of the coil, thereby increasing the size of the camera module. Therefore, the most desirable method to increase the driving force is to increase the magnetic force while maintaining the size of the magnet assembly.

[0014] However, as the magnetic force of the magnet increases, there is a concern about magnetic interference between magnets or between actuators, so magnetic field control technology is required that considers not only magnetic field amplification in the direction where a large magnetic field is needed but also magnetic field shielding in the direction where a magnetic field is not needed.

[0015] FIG. 1 is a drawing showing a magnet assembly applied to a conventional camera actuator, where (a) is a perspective view, (b) is a plan view, and (c) is a front view.

[0016] Referring to FIG. 1, the device includes a rectangular magnet part (1400) having an upper surface and a lower surface with different polarities, and an M-yoke (1800) in contact with the lower surface of the magnet part (1400), wherein the M-yoke (1800) is formed of a magnetic material.

[0017] When an M-yoke (1800) is formed using a magnetic material at the bottom of the magnet part (1400), the magnetic flux density in the direction where the M-yoke (1800) is not attached increases, and the magnetic flux density in the direction where the M-yoke (1800) is attached decreases. For example, the M-yoke (1800) is formed using SUS430, a type of stainless steel. SUS430 is a ferritic stainless steel that contains chromium (Cr) and possesses magnetism, so it is widely used as a material for forming the M-yoke (1800).

[0018] As the M-yoke (1800) absorbs magnetic field lines, it shields the magnetic force in the direction to which the M-yoke (1800) is attached and amplifies the magnetic force in the direction not to which the yoke (1800) is attached.

[0019] However, the magnetic field at the edge portion of the magnet part (1400) where the magnetic flux density is concentrated cannot be controlled, and there are limitations to shielding and amplification due to the low saturation magnetic flux density of stainless steel, SUS430.

[0020] Actuators employing such conventional magnet assemblies have limitations on miniaturization of components due to insufficient magnetic flux in regions requiring strong magnetic flux, which necessitates increasing the current in the coil section or making the coil section thicker to drive heavy lens assemblies, and insufficient shielding of magnetic flux in regions where it is not needed, which leads to interference with other magnet assemblies.

[0021] The technical problem that the present invention aims to solve is to provide a camera actuator using a magnet assembly capable of amplifying magnetic flux in areas where strong magnetic flux is required and shielding magnetic flux in areas where it is not required.

[0022] In addition, it provides a camera actuator with improved driving force and reduced size.

[0023] The technical problems of the present invention are not limited to those mentioned above, and other unmentioned technical problems will be clearly understood by those skilled in the art from the description below.

[0024] An actuator for a camera according to the present invention for solving the above technical problem comprises a housing, a first lens assembly and a second lens assembly that move along the optical axis direction within the housing, a first M-yoke and a second M-yoke fixed to the first lens assembly and the second lens assembly, a first magnet part and a second magnet part attached to the flat plates of the first M-yoke and the second M-yoke, and a first coil part and a second coil part fixed to the housing and driving the first magnet part and the second magnet part, wherein the first magnet part and the second magnet part have a plurality of magnets arranged in a Halbach arrangement, and the direction of their magnetic flux may be perpendicular to the optical side.

[0025] In some embodiments of the present invention, the first M-yoke or the second M-yoke may include a flat plate in contact with the lower surface of the magnet part and a side reinforcing member in contact with the side of the magnet part, and the upper end of the side reinforcing member may coincide with the upper surface of the magnet part.

[0026] In some embodiments of the present invention, the first M-yoke or the second M-yoke may further include additional reinforcing members that contact the front and back surfaces of the magnet part.

[0027] In some embodiments of the present invention, a first C-yoke and a second C-yoke installed on the outer surfaces of the first coil portion and the second coil portion may be further included.

[0028] In some embodiments of the present invention, the M yoke or the C yoke may be formed of a CoFe alloy.

[0029] In some embodiments of the present invention, the content of Co in the CoFe alloy may be 27% or more by weight.

[0030] In some embodiments of the present invention, the M yoke or the C yoke may be formed of silicon steel sheet.

[0031] In some embodiments of the present invention, the Si content of the silicon steel sheet may be in the range of 1% to 5% by weight.

[0032] In some embodiments of the present invention, the first M-yoke and the second M-yoke may have one side open facing inward perpendicular to the light side and the other side shielded.

[0033] In some embodiments of the present invention, one or more of the magnets may be characterized by having polarity divided diagonally.

[0034] The camera actuator according to the present invention can drive the lens assembly more powerfully with an improved driving force.

[0035] In addition, it can reduce interference caused by magnetic flux to other parts.

[0036] In addition, the reduced size can contribute to the miniaturization of mobile devices in which the actuator is employed.

[0037] Figure 1 is a drawing showing a conventional magnet assembly.

[0038] FIG. 2 is a cross-sectional view of a magnet assembly according to an embodiment of the present invention.

[0039] FIG. 3 is a perspective view of a magnet assembly according to an embodiment of the present invention.

[0040] Figure 4 is a diagram showing the magnetic flux density by shielding material of the yoke.

[0041] FIG. 5 is a diagram showing the amplification of magnetic flux density according to an embodiment of the present invention.

[0042] FIG. 6 is a diagram showing the shielding of magnetic flux density according to an embodiment of the present invention.

[0043] FIG. 7 is a perspective view of a camera actuator according to an embodiment of the present invention.

[0044] Figure 8 is a cross-sectional view cut along BB' in Figure 7.

[0045] FIG. 9 is a perspective view showing the driving-related parts of the actuator according to FIG. 7.

[0046] FIG. 10 is a diagram showing the thrust of an actuator according to an embodiment of the present invention.

[0047] FIG. 11 is a drawing for explaining the crosstalk of an actuator according to an embodiment of the present invention.

[0048] FIG. 12 is a diagram showing the crosstalk of an actuator according to an embodiment of the present invention.

[0049] The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims. Throughout the specification, the same reference numerals refer to the same components.

[0050] "And / or" includes each of the mentioned items and all combinations of one or more.

[0051] The terms used herein are for describing embodiments and are not intended to limit the invention. In this specification, the singular form includes the plural form unless specifically stated otherwise in the text. As used herein, "comprising" and / or "comprising" does not exclude the presence or addition of one or more other components, steps, actions, and / or elements to the mentioned components, steps, actions, and / or elements.

[0052] Furthermore, throughout the specification, when a part is described as being "connected" to another part, this includes not only cases where they are "directly connected," but also cases where they are "indirectly" or "electrically connected" with other members or elements interposed between them.

[0053] Additionally, throughout the specification, the description that each layer (film), region, pattern, or structure is formed "on" or "under" the substrate, each layer (film), region, pad, or pattern includes both direct formation and formation through another layer. The criteria for "on" or "under" each layer are described based on the drawings.

[0054] Furthermore, expressions such as 'first, second,' etc., are used solely to distinguish multiple compositions and do not limit the order or other characteristics between the compositions.

[0055] Unless otherwise defined, all terms used in this specification (including technical and scientific terms) may be used in a meaning commonly understood by those skilled in the art to which the present invention pertains. Additionally, terms defined in commonly used dictionaries are not to be interpreted ideally or excessively unless explicitly and specifically defined otherwise.

[0056] In Figures 2 and 3, the positive direction of the Z-axis is set to upward and the negative direction to downward, the positive direction of the X-axis to the right and the negative direction to the left, and the negative direction of the Y-axis to the front and the positive direction to the back.

[0057] Hereinafter, a magnet assembly according to the present invention and an actuator for a camera including the same will be described with reference to the drawings.

[0058] FIG. 2 is a cross-sectional view of a magnet assembly according to an embodiment of the present invention, and FIG. 3 is a perspective view.

[0059] Referring to FIG. 2 and FIG. 3, a magnet assembly (100) according to one embodiment of the present invention may include a magnet part (1400) in which one or more magnets (1401, 1402, 1403) are formed in the shape of a cuboid, and an M-yoke (1800) that contacts at least a portion of the lower surface, left side, and right side of the magnet part (1400).

[0060] At this time, the magnet portion (1400) may be formed by arranging a plurality of magnets (1401, 1402, 1403) in a Halbach arrangement, and at least one of the magnets may be characterized by having polarity divided diagonally.

[0061] Referring to FIG. 2, a plurality of magnets (1401, 1402, 1403) may be arranged in a first direction (e.g., the x-axis of FIG. 2) so as to be in contact with each other, and the magnets (1401, 1402, 1403) may be rotated counterclockwise (or clockwise) along the first direction to form a Halbach arrangement. Additionally, the upper surface of each magnet (1401, 1402, 1403) may be arranged with the same polarity (N, S) as the upper surface of any one of the magnets (1401, 1402, 1403) adjacent in the first direction. Furthermore, the lower surface of each magnet (1401, 1402, 1403) is characterized by having a different polarity (N, S) as the lower surface of any one of the magnets (1401, 1402, 1403) adjacent in the first direction. In this case, if the upper surface or the lower surface includes two polarities, the upper surface or the lower surface may refer to a portion of the area that contacts another magnet in the first direction.

[0062] According to the embodiment, the second magnet (1402) has an N pole located on its upper surface, and the area of ​​the upper surface of the first magnet (1401) adjacent to one side of the second magnet (1402) that contacts the upper surface of the second magnet (1402) has an N pole located in the same manner. At the same time, the area of ​​the upper surface of the third magnet (1403) adjacent to the other side of the second magnet (1402) that contacts the upper surface of the second magnet (1402) has an N pole located in the same manner. Therefore, the first to third magnets (1401, 1402, 1403) can be formed in a shape in which N poles are gathered on their upper surfaces and arranged in a Halbach arrangement.

[0063] In the case of FIG. 2(a), the first magnet (1401) is magnetized in the direction of the -x axis, the second magnet (1402) in the direction of the -z axis (rotated 90 degrees from the direction of the first magnet (1401)), and the third magnet (1403) in the direction of the +x axis (rotated 90 degrees from the direction of the second magnet (1402)), so that the first to third magnets (1401, 1402, 1403) can be arranged in a Halbach arrangement in which polarity is divided in the horizontal or vertical direction.

[0064] In the case of FIG. 2(b), the first magnet (1401) is magnetized in a direction that divides the -x and -z axes in half at 45 degrees, the second magnet (1402) is magnetized in the direction of the -z axis, and the third magnet (1403) is magnetized in a direction that divides the +x and -z axes in half at 45 degrees, so that the first magnet (1401) and the third magnet (1403) can be arranged in a Halbach arrangement in which polarity is divided diagonally.

[0065] In the case of a magnet section (1400) including magnets (1401, 1403) in which polarity is divided diagonally in this manner, the maximum amplification of magnetic flux density is lowered in the direction where the same polarity converges, while the difference between the maximum amplification and the minimum amplification is reduced, so that a flat amplification can be achieved. Such a flat amplification is advantageous for driving with a constant thrust during the operating range when applied to a driving part such as an electronic device.

[0066] The magnet section arranged in a Halbach array can concentrate magnetic force in the direction where it is needed and reduce magnetic force in the direction where it is not needed by arranging multiple magnets in a specific direction.

[0067] Referring to FIG. 3, the M-yoke (1800) may include a flat plate (1801) that contacts the lower surface of the magnet part (1400) and side reinforcing parts (1803) that contact the left and right sides of the magnet part (1400).

[0068] The side reinforcement (1803) can be formed by wrapping the left and right sides of the magnet part (1400) in the longitudinal direction (X-axis direction) and bending upward (+Z-axis direction), and the height of the side reinforcement (1803) can be formed to be equal to the height of the magnet part (1400).

[0069] Additionally, the above M-yoke (1800) may further include additional reinforcing members (1805) that contact the front and back surfaces.

[0070] The additional reinforcing member (1805) can be formed by wrapping the front and back sides of the magnet part (1400) in the width direction (Y-axis direction) and bending upward (+Z-axis direction), and the height of the additional reinforcing member (1805) can be formed to be equal to the height of the magnet part (1400).

[0071] Therefore, the M-yoke (1800) may be a hollow cuboid shape that opens the top of the magnet part (1400) and contacts the remaining five faces. Thus, the magnets (1401, 1402, 1403) inserted into the M-yoke (1800) can be restrained from being pushed out in all directions except the upward direction.

[0072] The M yoke (1800) can shield by amplifying the magnetic flux density in the direction toward the open side and reducing the magnetic flux density in the direction toward the contact side.

[0073] When an M-yoke (1800) formed of a magnetic material is brought into contact with the magnet part (1400), the M-yoke (1800) absorbs magnetic field lines, thereby shielding the magnetic force in the direction to which the M-yoke (1800) is attached and amplifying the magnetic force in the direction not to which the M-yoke (1800) is attached. Therefore, the magnetic flux density in the direction not to which the M-yoke (1800) is attached increases, and the magnetic flux density in the direction to which the M-yoke (1800) is attached decreases.

[0074] As such, the magnet assembly (100) according to the embodiment can concentrate magnetic force in the direction where magnetic force is needed and double the effect of reducing magnetic force in the direction where magnetic force is not needed by forming an M-yoke (1800) in accordance with the Halbach arrangement.

[0075] The M yoke (1800) according to the present invention may be formed of a magnetic material capable of exhibiting a shielding effect, but preferably may be formed of a ferromagnetic material capable of enhancing the shielding effect.

[0076] That is, it is formed from a material having a higher saturation magnetic flux density than the stainless steel shielding material (SUS 430) used as the yoke of a conventional magnet assembly, so that the magnetic flux density can be amplified and the strength of the shielding can be increased.

[0077] Ferromagnetic materials can be used as shielding materials by concentrating magnetic flux within the material to prevent the influence of the magnetic field from reaching other areas.

[0078] The magnetic shielding rate follows the formula below.

[0079] Magnetic shielding rate ∝ Permeability x Thickness

[0080] As such, the higher the permeability of the shielding material, the higher the shielding rate, and the thicker the shielding material, the higher the shielding rate.

[0081] The objective of the present invention is to increase the amplification of magnetic flux density and the shielding effect compared to a conventional magnet assembly, so an M-yoke (1800) can be formed using a material having a higher permeability than a conventional shielding material.

[0082] Figure 4 is a graph showing the magnetic flux density of shielding materials, where the horizontal axis represents the strength of the formed magnetic field in units of A / m, and the vertical axis represents the strength of the magnetic field formed by the magnetic field and the magnetization of the shielding material in units of Tesla.

[0083] When the strength of a magnetic field is formed in the form of contour lines around a magnet, centered on the two ends of the magnet, namely the N or S pole, the strength of the enhanced magnetic field can be confirmed by adding a shielding material within the region where the magnetic field is formed.

[0084] Referring to FIG. 4, when a yoke is formed for each shielding material at a location where a magnetic field of 5 kA / m is formed, the magnetic flux density amplified by the magnet and the M-yoke (1800) can be compared.

[0085] Referring to the first graph (solid line) from the top, a CoFe alloy containing 49% by weight of Co (cobalt) exhibits a magnetic flux density of 2.2T or higher at a location where a magnetic field of 5kA / m is formed. In this case, as the Co content increases, the permeability increases, leading to a higher magnetic flux density; while this is advantageous for securing amplification and shielding effects, it may increase costs. According to experiments, a CoFe alloy containing 27% or more by weight of Co exhibits a magnetic flux density of 2.2T or higher at a location where a magnetic field of 5kA / m is formed.

[0086] Referring to the second graph from the top (dotted line), a silicon steel sheet containing 3% by weight of Si (silicon) exhibits a magnetic flux density of 2.0 or higher at a location where a magnetic field of 5 kA / m is formed. According to the experiment, a silicon steel sheet containing 1% to 5% by weight of Si (silicon) exhibits a magnetic flux density of 2.0 T or higher at a location where a magnetic field of 5 kA / m is formed.

[0087] Referring to the third graph from the top (dotted line), it shows a conventional case formed with a stainless steel shield (SUS 430) as the shielding material, and shows a magnetic flux density of 1.6T at a location where a magnetic field of 5kA / m is formed.

[0088] As such, it can be confirmed that the magnetic flux density of a shielding material formed from a CoFe alloy containing 27% or more of Co (cobalt) by weight or a silicon steel sheet containing 1% to 5% of Si (silicon) by weight is greater than the magnetic flux density of a conventionally used stainless steel shielding material (SUS 430). Therefore, the yoke according to the embodiment can have a high shielding effect and amplification degree.

[0089] FIG. 5 is a diagram showing the amplification of magnetic flux density with a yoke applied according to an embodiment of the present invention.

[0090] Referring to Fig. 5, the horizontal axis represents the length in the horizontal direction (X-axis direction) where the magnet is installed in mm, and the vertical axis represents the magnetic flux density measured in mT at a position 5 mm above the magnet (positive Z-axis direction).

[0091] The thick solid line (the fourth line from the top) represents a conventional magnet assembly (100), and the thin solid line (the first line from the top) and the dashed line (the second line from the top) represent a magnet assembly (100) according to an embodiment of the present invention.

[0092] The thin solid line indicates the case where CoFe alloy is applied as the magnet part (1400) of the Halbach array and the shielding material, and the dashed line indicates the case where silicon steel plate is applied as the magnet part (1400) of the Halbach array and the shielding material.

[0093] The 2-dot dashed line (the third line from the top) is the case where the magnet part (1400) of the Halbach array is applied and the shielding material is a conventional stainless steel shielding material (SUS 430).

[0094] When comparing the graph of the black line (conventional magnet part) and the thin solid line, it can be seen that the magnetic flux density of the magnet assembly (100) according to the embodiment of the present invention is strengthened by about 8.3% in the central part of the magnet assembly (100) and about 12.7% in the leading parts at both ends compared to the conventional magnet assembly.

[0095] When comparing the graph of the thick solid line (conventional magnet part) and the dashed line, it can be seen that the magnet assembly (100) according to the embodiment of the present invention has a magnetic flux density that is strengthened by about 5.5% in the central part of the magnet assembly (100) and about 10.8% in the leading parts at both ends compared to the conventional magnet assembly.

[0096] At this time, the length of the amplified area satisfies a range of 6 to 7 mm. Since the driving distance of the magnet assembly (100) moving in the actuator to which the magnet assembly (100) according to the embodiment of the present invention is applied is 5 to 6 mm, stable driving of the actuator is possible.

[0097] In this way, by applying a magnet part (1400) formed with a Halbach array of magnets, the magnetic flux of the magnet part (1400) is strengthened, and at the same time, the shape and material of the M yoke (1800) are reinforced, thereby obtaining a magnet assembly (100) that achieves an improved amplification effect compared to a conventional magnet assembly (100).

[0098] FIG. 6 is a diagram showing the shielding of magnetic flux density with a yoke applied according to an embodiment of the present invention.

[0099] Referring to Fig. 6, the horizontal axis represents the length in the horizontal direction (X-axis direction) where the magnet is installed in mm, and the vertical axis represents the magnetic flux density measured in mT at a position 5 mm downward (negative Z-axis direction) from the magnet.

[0100] The thick solid line (the first line from the top) represents a conventional magnet assembly (100), and the dashed line (the third line from the top) and the thin solid line (the fourth line from the top) represent a magnet assembly (100) according to an embodiment of the present invention.

[0101] The dashed line indicates the case where silicon steel plate is applied as the magnet part (1400) of the Halbach array and the shielding material, and the thin solid line indicates the case where CoFe alloy is applied as the magnet part (1400) of the Halbach array and the shielding material.

[0102] The two-dot dashed line (second line from the top) is the case where the magnet part (1400) of the Halbach array is applied and the shielding material is a conventional stainless steel shielding material (SUS 430).

[0103] When comparing the graph of the thick solid line (conventional magnet part) and the thin solid line, it can be seen that the magnet assembly (100) according to the embodiment of the present invention has an improved shielding effect such that the magnetic flux density in the central part of the magnet assembly (100) is reduced by about 24.9% compared to the conventional magnet assembly.

[0104] When comparing the graph of the thick solid line (conventional magnet part) and the dashed line, it can be seen that the magnet assembly (100) according to the embodiment of the present invention has an improved shielding effect such that the magnetic flux density in the central part of the magnet assembly (100) is reduced by about 20.2% compared to the conventional magnet assembly.

[0105] In this way, by applying a magnet part (1400) formed with a Halbach array of magnets and simultaneously reinforcing the shape and material of the M-yoke (1800), a magnet assembly (100) with a shielding effect that is significantly improved compared to a conventional magnet assembly (100) can be obtained.

[0106] Next, an embodiment of a camera actuator to which a magnet assembly according to the present invention is applied will be described with reference to the drawings.

[0107] FIG. 7 is a perspective view of a camera actuator according to an embodiment of the present invention, FIG. 8 is a cross-sectional view cut along BB' in FIG. 7, and FIG. 9 is a perspective view showing a driving-related component of the actuator according to FIG. 7.

[0108] In FIGS. 7 to 9, the first direction is the X-axis direction in the drawing, and the second direction is the Y-axis direction in the drawing. The second direction is perpendicular to the first direction. Also, the third direction is the Z-axis direction in the drawing. It is a direction perpendicular to both the first direction and the second direction. Here, the third direction (Z-axis direction) corresponds to the direction of the optical axis, and the first direction (X-axis direction) and the second direction (Y-axis direction) are directions perpendicular to the optical axis. Additionally, in the description of the camera actuator (1000) below, the optical axis direction corresponds to the optical path and is the third direction (Z-axis direction).

[0109] Referring to FIGS. 7 to 9, an actuator for a camera according to the present invention comprises a housing (1100), a first lens assembly (1200) and a second lens assembly (1300) that move along an optical axis direction within the housing (1100), a first M-yoke (1810) and a second M-yoke (1820) fixed to the first lens assembly (1200) and the second lens assembly (1300), a first magnet part (1410) and a second magnet part (1420) attached to the flat plates of the first M-yoke (1810) and the second M-yoke (1820), and a first coil part (1710) and a second coil part (1720) fixed to the housing and driving the first magnet part (1410) and the second magnet part (1420), wherein the first The magnet section (1410) and the second magnet section (1420) have a plurality of magnets arranged in a Halbach arrangement, and the direction of their magnetic flux may be perpendicular to the light side.

[0110] A first magnet assembly (100a) disposed on the first lens assembly (1200) may include a first magnet part (1410) and a first M-yoke (1810), and a second magnet assembly (100b) disposed on the second lens assembly (1300) may include a second magnet part (1420) and a second M-yoke (1820).

[0111] The first magnet assembly (100a) may include a first magnet part (1410) formed by arranging a plurality of magnets in a Halbach arrangement and a first M-yoke (1810) in contact with the lower surface and side of the first magnet part (1410), and the second magnet assembly (100b) may include a second magnet part (1420) formed by arranging a plurality of magnets in a Halbach arrangement and a second M-yoke (1820) in contact with the lower surface and side of the second magnet part (1420).

[0112] The first M-yoke (1810) and the second M-yoke (1820) have the same shape and function as the aforementioned M-yoke (1800).

[0113] A camera actuator (1000) according to an embodiment may include a housing (1100), a first lens assembly (1200) and a second lens assembly (1300), a first magnet part (1410) and a second magnet part (1420), a first M-yoke (1810) and a second M-yoke (1820), a substrate (1500), a housing cover (1600), a first coil part (1710) and a second coil part (1720), and a stopper part (S).

[0114] The housing (1100) may form the outer wall of the camera actuator (1000). A housing cover (1600) may be placed on one side of the housing (1100). Inside the housing (1100), a first lens assembly (1200) and a second lens assembly (1300), a first magnet part (1410) and a second magnet part (1420), a first M-yoke (1810) and a second M-yoke (1820), a first coil part (1710) and a second coil part (1720), and a stopper part (S) may be included.

[0115] On the side parallel to the optical axis direction of the housing (1100), a first magnet part (1410), a first coil part (1710), and a first M-yoke (1810) are arranged for driving the first lens assembly (1200), and a second magnet part (1420), a second coil part (1720), and a second M-yoke (1820) may be arranged for driving the second lens assembly (1300).

[0116] At this time, the open surface of the first M-yoke (1810) is positioned in the direction of the first coil section (1710), and the shielding surface is positioned in the inward direction. The open surface of the second M-yoke (1820) is positioned in the direction of the second coil section (1720), and the shielding surface is positioned in the inward direction. Therefore, the shielding surfaces of the first M-yoke (1810) and the second M-yoke (1820) can face each other.

[0117] A surface perpendicular to the optical axis direction of the housing (1100) may include an opening. A substrate (1500) may be disposed on the outside of the housing (1100).

[0118] A camera actuator (1000) according to an embodiment may include a first lens assembly (1200) and a second lens assembly (1300).

[0119] The first lens assembly (1200) and the second lens assembly (1300) may be moving lenses that move through a coil, a magnet, and a guide pin.

[0120] The second lens assembly (1300) can perform the function of a variantr that re-forms the image formed by focusing light into another location. Meanwhile, the distance to the subject or the image distance may change significantly in the second lens assembly (1300), resulting in a large change in magnification, and the second lens assembly (1300), as a variantr, can play an important role in the change in focal length or magnification of the optical system.

[0121] Meanwhile, the image formed by the second lens assembly (1300), which is a variable, may differ slightly depending on the position. Accordingly, the first lens assembly (1200) can perform a position compensation function for the image formed by the variable. For example, the first lens assembly (1200) can perform a compensator function that accurately forms the image formed by the second lens assembly (1300), which is a variable, at the actual image sensor position. In an embodiment, the first lens assembly (1200) and the second lens assembly (1300) can be driven by electromagnetic force resulting from the interaction between a coil and a magnet.

[0122] The first lens assembly (1200) and the second lens assembly (1300) can be placed inside the housing (1100).

[0123] The first lens assembly (1200) and the second lens assembly (1300) can move along the optical axis direction inside the housing (1100) by means of the magnet part (1400), the yoke (1800), and the coil part (1700).

[0124] The first lens assembly (1200) and the second lens assembly (1300) may be spaced apart from each other along the optical axis direction. The first lens assembly (1200) and the second lens assembly (1300) may partially overlap with the stopper portion (S) in the optical axis direction. The first lens assembly (1200) and the second lens assembly (1300) may partially overlap with the housing cover (1600) in the optical axis direction.

[0125] The first lens assembly (1200) can be driven by a first magnet assembly (100a) in which a first magnet part (1410) and a first M-yoke (1810) are combined. The first lens assembly (1200) can be coupled with the first M-yoke (1810). The first lens assembly (1200) is coupled with the first M-yoke (1810), and the first magnet part (1410) is coupled to the first M-yoke (1810), so that the first magnet part (1410) can be fixed to the first lens assembly (1200). The first lens assembly (1200) can be superimposed with the first coil part (1710) in a first direction perpendicular to the optical axis direction. The first lens assembly (1200) can be overlapped in the optical axis direction with the first stopper (S1), the third stopper (S3), and the fifth stopper (S5).

[0126] The second lens assembly (1300) can be driven by a second magnet assembly (100b) in which the second magnet part (1420) and the second M-yoke (1820) are combined. The second lens assembly (1300) can be combined with the second M-yoke (1820). The second lens assembly (1300) is combined with the second M-yoke (1820), and the second magnet part (1420) is combined with the second M-yoke (1820), so that the second magnet part (1420) can be fixed to the second lens assembly (1300). The second lens assembly (1300) can be superimposed with the second coil part (1720) in a first direction perpendicular to the optical axis direction. The second lens assembly (1300) can be superimposed with the second stopper (S2) and the fourth stopper (S4) in the optical axis direction.

[0127] The camera actuator (1000) according to the embodiment may include a substrate (1500).

[0128] A substrate (1500) may be placed in a housing (1100). A substrate (1500) may be placed on the outside of the housing (1100). A driver IC (not shown) and a coil section (1700) may be placed on the substrate (1500). A driver IC and a coil section (1700) may be placed on the inside of the substrate (1500). The substrate (1500) may fix the driver IC and the coil section (1700). The substrate (1500) may transmit information of an optical signal from the driver IC to the coil section (1700).

[0129] The substrate (1500) may include a first sub-substrate (1510), a second sub-substrate (1520), and a third sub-substrate (1530).

[0130] A first sub-substrate (1510) may be placed on the side of the housing (1100). The first sub-substrate (1510) may be placed in the optical axis direction and a second direction. A second sub-substrate (1520) may be placed on the upper surface of the housing. The second sub-substrate (1520) may be placed in the optical axis direction and a first direction. A third sub-substrate (1530) may be placed on the side of the housing (1100). The third sub-substrate (1530) may be placed in the optical axis direction and a second direction. The first sub-substrate (1510) and the third sub-substrate (1530) may be placed parallel to each other. The first sub-substrate (1510) and the third sub-substrate (1530) may be placed perpendicular to the second sub-substrate (1520). A second coil section (1720) may be placed on a first sub-substrate (1510), and a first coil section (1710) may be placed on a third sub-substrate (1530).

[0131] A second C-yoke (1920) is arranged in parallel with the first sub-sub

[0132] The first C-yoke (1910) and the second C-yoke (1920) can be formed in the shape of a square plate made of a ferromagnetic material to shield electromagnetic waves radiated from one side of the first sub-substrate (1510) and the third sub-substrate (1530), and can be installed on the outer surface of the first sub-substrate (1510) and the third sub-substrate (1530).

[0133] The first C-yoke (1910) and the second C-yoke (1920) can be formed from a CoFe alloy containing 27% or more of Co (cobalt) by weight or a silicon steel plate containing 1% to 5% of Si (silicon) by weight, which is the same material as the M-yoke (1800) to form the shielding effect.

[0134] Accordingly, the camera actuator (1000) according to the embodiment can satisfy the miniaturization design requirements of a mobile electronic device to which the camera actuator is applied by reducing the amount of electromagnetic waves unnecessarily radiated to the outside.

[0135] The camera actuator (1000) according to the embodiment may include a housing cover (1600).

[0136] The housing cover (1600) may be fixedly positioned on one side of the housing (1100). The housing cover (1600) may overlap with the housing (1100) in the direction of the optical axis. A first stopper part (Sa) may be positioned on the housing cover (1600).

[0137] The housing cover (1600) may partially overlap with the first lens assembly (1200) and the second lens assembly (1300) in the direction of the optical axis.

[0138] The camera actuator (1000) according to the embodiment may include a stopper part (S).

[0139] The stopper part (S) may be disposed inside the housing (1100). The stopper part (S) may be disposed inside the housing (1100) to prevent the first lens assembly (1200) and the second lens assembly (1300) from colliding inside the housing (1100). The stopper part (S) may absorb impact by contacting the first lens assembly (1200) and the second lens assembly (1300). The stopper part (S) may include a Poron. The shape of the stopper part (S) is not limited. For example, the stopper part (S) may include a rectangular shape.

[0140] The stopper portion (S) may include a first stopper portion (Sa) and a second stopper portion (Sb). The first stopper portion (Sa) may be disposed on the housing cover (1600). The first stopper portion (Sa) may be disposed on one side of the housing cover (1600) facing the interior of the housing (1100). The first stopper portion (Sa) may be disposed on the housing cover (1600) so as to overlap with the first lens assembly (1200) or the second lens assembly (1300). The second stopper portion (Sb) may be disposed on one side of the interior of the housing (1100). The second stopper portion (Sb) may be disposed on one side of the interior of the housing (1100) so as to overlap with the first lens assembly (1200) or the second lens assembly (1300) in the direction of the optical axis. The first stopper part and the second stopper part may be spaced apart from each other in opposite directions in the optical axis direction with respect to the first lens assembly (1200) and the second lens assembly (1300).

[0141] The first stopper part (Sa) may include a first stopper (S1) and a second stopper (S2). The first stopper (S1) and the second stopper (S2) may be spaced apart from each other in a first direction.

[0142] The first stopper (S1) can overlap with the first lens assembly (1200) in the direction of the optical axis.

[0143] The second stopper (S2) can overlap with the second lens assembly (1300) in the direction of the optical axis.

[0144] The first stopper (S1) can come into contact with the bottom of the first lens assembly (1200).

[0145] The second stopper (S2) can come into contact with the bottom of the second lens assembly (1300).

[0146] The second stopper portion (Sb) may include a third stopper (S3), a fourth stopper (S4), and a fifth stopper (S5). The third stopper (S3), the fourth stopper (S4), and the fifth stopper (S5) may be spaced apart from each other in a first direction. The third stopper (S3) and the fifth stopper (S5) may overlap with the first lens assembly (1200) in the optical axis direction. The fourth stopper (S4) may overlap with the second lens assembly (1300) in the optical axis direction. The third stopper (S3), the fourth stopper (S4), and the fifth stopper (S5) may be placed at different heights inside the housing (1100) in the optical axis direction. The fifth stopper (S5) may be placed between the third stopper (S3) and the fourth stopper (S4) in the first direction. The third stopper (S3) can contact the top of the first lens assembly (1200). The fourth stopper (S4) can contact the top of the second lens assembly (1300).

[0147] The first to fourth stoppers (S1, S2, S3, S4) may not overlap with the second magnet part (1420) in the first direction. When the second lens assembly (1300) moves to the top of the housing (1100) and comes into contact with the fourth stopper (S4), the second magnet part (1420) may not overlap with the third stopper (S3) and the fourth stopper (S4) in the first direction. Additionally, when the second lens assembly (1300) moves to the bottom of the housing (1100) and comes into contact with the second stopper (S2), the second magnet part (1420) may not overlap with the first stopper (S1) and the second stopper (S2) in the first direction.

[0148] The fifth stopper (S5) may overlap with the magnet part (1420) in the first direction. When the first lens assembly (1200) and the second lens assembly (1300) move to the top of the housing (1100) and come into contact with the third stopper (S3) and the fourth stopper (S4), the first magnet part (1410) and the second magnet part (1420) may overlap with the fifth stopper (S5) in the first direction.

[0149] The camera actuator (1000) according to the embodiment may include a first magnet part (1410) and a second magnet part (1420).

[0150] The first magnet part (1410) is placed on the first lens assembly (1200) and the second magnet part (1420) is placed on the second lens assembly (1300) so as to move the first lens assembly (1200) and the second lens assembly (1300).

[0151] The first magnet part (1410) and the second magnet part (1420) can move the first lens assembly (1200) and the second lens assembly (1300) by receiving magnetic force from the first coil part (1710) and the second coil part (1720), respectively.

[0152] The first magnet part (1410) and the second magnet part (1420) can be positioned in a first direction on the side of the first lens assembly (1200) and the second lens assembly (1300).

[0153] The first magnet part (1410) can be placed between the first lens assembly (1200) and the first coil part (1710), and the second magnet part (1420) can be placed between the second lens assembly (1300) and the first coil part (1720).

[0154] The first magnet part (1410) and the second magnet part (1420) can each overlap with the first coil part (1710) and the second coil part (1720) in the first direction.

[0155] The first magnet part (1410) and the second magnet part (1420) can be fixed to the first lens assembly (1200) and the second lens assembly (1300) respectively by the first M-yoke (1810) and the second M-yoke (1820).

[0156] A first M-yoke (1810) is positioned between the first magnet part (1410) and the first lens assembly (1200) so that the first M-yoke (1810) fixes the first magnet part (1410) onto the first lens assembly (1200), and a second M-yoke (1820) is positioned between the second magnet part (1420) and the second lens assembly (1300) so that the second M-yoke (1820) fixes the second magnet part (1420) onto the second lens assembly (1300).

[0157] The magnet portion (1400) may include a first magnet portion (1410) disposed on a first lens assembly (1200) and a second magnet portion (1420) disposed on a second lens assembly (1300).

[0158] The first magnet part (1410) may be placed on the first lens assembly (1200). The first magnet part (1410) may move the first lens assembly (1200). The first magnet part (1410) may be placed on a side perpendicular to the first direction of the first lens assembly (1200). The first magnet part (1410) may be placed between the first lens assembly (1200) and the first coil part (1710). The first magnet part (1410) may be fixed on the first lens assembly (1200) by the first M-yoke (1810). A first M-yoke (1810) is positioned between the first magnet part (1410) and the first lens assembly (1200) so that the first M-yoke (1810) can fix the first magnet part (1410) on the first lens assembly (1200). The first magnet part (1410) may not overlap with the first to third stoppers (S1, S2, S3) in the first direction.

[0159] The second magnet part (1420) may be placed on the second lens assembly (1300). The second magnet part (1420) may move the second lens assembly (1300). The second magnet part (1420) may be placed on a side perpendicular to the first direction of the second lens assembly (1300). The second magnet part (1420) may be placed between the second lens assembly (1300) and the second coil part (1720). The second magnet part (1420) may be fixed on the second lens assembly (1300) by the second M-yoke (1820). A second M-yoke (1820) is positioned between the second magnet part (1420) and the second lens assembly (1300) so that the second M-yoke (1820) can fix the second magnet part (1420) onto the second lens assembly (1300). The second magnet part (1420) may not overlap with the first to fourth stoppers (S1, S2, S3, S4) in the first direction.

[0160] In the embodiment, the first magnet section (1410) and the second magnet section (1420) may be the magnet section (1400) of FIG. 2. The first magnet section (1410) and the second magnet section (1420) may include a plurality of magnets arranged in a Halbach array. For example, the first magnet section (1410) and the second magnet section (1420) may each include a first magnet (1401), a second magnet (1402), and a third magnet (1403). The plurality of magnets included in the first magnet section (1410) and the second magnet section (1420) may be arranged sequentially side by side along the optical axis direction. For example, the first magnet (1411), the second magnet (1412), and the third magnet (1413) may be arranged sequentially side by side along the optical axis direction. Additionally, the upper surface of the first magnet part (1410) may be arranged in one direction of the x-axis direction, and the upper surface of the second magnet part (1420) may be arranged facing the other direction of the x-axis direction.

[0161] Referring to FIGS. 7 to 9, a camera actuator (1000) according to an embodiment may include a first M-yoke (1810) disposed between a first lens assembly (1200) and a first magnet part (1410), and a second M-yoke (1820) disposed between a second lens assembly (1300) and a second magnet part (1420).

[0162] The first M-yoke (1810) may be positioned between the first lens assembly (1200) and the first magnet part (1410) to fix the first magnet part (1410) onto the first lens assembly (1200), and the second M-yoke (1820) may be positioned between the second lens assembly (1300) and the second magnet part (1420) to fix the second magnet part (1420) onto the second lens assembly (1300). The first M-yoke (1810) and the second M-yoke (1820) may be positioned in a first direction on the side of the first lens assembly (1200) and the second lens assembly (1300).

[0163] The yoke (1800) may include a first M-yoke (1810) positioned between the first lens assembly (1200) and the first magnet part (1410), and a second M-yoke (1820) positioned between the second lens assembly (1300) and the second magnet part (1420).

[0164] The first M-yoke (1810) may be positioned between the first lens assembly (1200) and the first magnet part (1410). The first M-yoke (1810) may be positioned on the side of the first lens assembly (1200) to secure the first magnet part (1410) onto the first lens assembly (1200).

[0165] The second M-yoke (1820) may be positioned between the second lens assembly (1300) and the second magnet part (1420). The second M-yoke (1820) may be positioned on the side of the second lens assembly (1300) to secure the second magnet part (1420) onto the second lens assembly (1300).

[0166] When current flows through the first coil part (1710) and the second coil part (1720), which are respectively located within the magnetic field formed by the first magnet part (1410) and the second magnet part (1420), a Lorentz force is generated, and the first magnet assembly (100a) and the second magnet assembly (100b), respectively, are driven.

[0167] As the magnitude of the magnetic field radiated in the direction of the coil portion (1700) increases, the driving force of the magnet assembly (100) increases, and thus the driving force of the lens assembly (1200, 1300) fixed to the magnet assembly (100) also increases. At this time, the magnetic field radiated in the opposite direction to the direction of the coil portion (1700) may cause interference with the operation of other magnets or other electronic components.

[0168] As such, appropriate amplification or shielding according to the radiation direction of the magnetic field of the magnet assembly (100) is important for the performance of the actuator.

[0169] The driving force (F) applied to the magnet assembly (100) is obtained according to the following.

[0170] F (driving force) = B (magnetic force) × I (current) × L (coil length)

[0171] That is, the driving force (F) is proportional to the magnitude (I) of the current applied to the coil section (1700), the length (L) of the coil section (1700), and the magnetic force (B) of the magnet assembly (100).

[0172] The magnet assembly according to the present invention amplifies the magnetic flux in the region requiring strong magnetic flux, thereby making it possible for the camera actuator of the present invention employing the same to drive the lens module with a stronger driving force using the same current and coil.

[0173] FIG. 10 is a drawing showing the thrust of an actuator according to an embodiment of the present invention, where the horizontal axis represents the stroke driven by the actuator in mm units, and the vertical axis represents the thrust driven by the magnet in μN units.

[0174] At this time, the thick solid line represents the thrust of an actuator with a conventional magnet assembly, the dashed line represents the thrust of an actuator with a yoke made of CoFe alloy, the two-dot dashed line represents the thrust of an actuator including a Halbach magnet, and the thin solid line represents the thrust of an actuator including a yoke made of CoFe alloy and a Halbach magnet.

[0175] An actuator (dashed line) including a yoke with CoFe alloy applied improves thrust by about 7.0% compared to a conventional actuator.

[0176] An actuator (thin solid line) including a yoke and Halbach magnet made of CoFe alloy improves thrust by approximately 13.6% compared to a conventional actuator. By mutually compensating for each deviation, the actuator (thin solid line) has flat characteristics throughout the entire stroke range and can achieve the greatest thrust through easy current control.

[0177] According to experiments, an actuator (not shown) including a reinforcing member, a yoke formed of silicon steel sheet material, and a Halbach magnet also improves thrust by about 10% compared to a conventional actuator.

[0178] Since the magnet assembly according to the present invention can shield magnetic flux in areas where it is not needed at a lower level, the camera actuator of the present invention employing it can reduce its size.

[0179] FIG. 11 is a drawing for explaining the crosstalk of an actuator according to an embodiment of the present invention.

[0180] Referring to FIG. 11, a first magnet part (1410), a first M-yoke (1810), and a first coil part (1710) are arranged for driving a first lens assembly (1200), and a second magnet part (1420), a second M-yoke (1820), and a second coil part (1720) are arranged for driving a second lens assembly (1300), so that the shielding surfaces of the first M-yoke (1810) and the second M-yoke (1820) can face each other.

[0181] The shielding surface of the first M-yoke (1810) is positioned toward the second magnet part (1420). The magnetic flux of the first magnet part (1410) can penetrate the shielding surface of the first coil part (1710) of the first M-yoke (1810) and interfere with the second magnet part (1420). At the same time, since the shielding surface of the second M-yoke (1820) is positioned toward the first magnet part (1420), the magnetic flux of the second magnet part (1420) can penetrate the shielding surface of the second M-yoke (1820) and interfere with the first magnet part (1410).

[0182] Conventionally, there was a problem in that it was difficult to reduce the spacing between the first lens assembly (1200) and the second lens assembly (1300) due to such interference, but the camera actuator according to the embodiment can overcome this problem by reducing the magnetic flux given to other magnet parts, thereby reducing the size of the camera actuator.

[0183] By using the second lens sensors (H1 to H4) installed in the second coil section (1720), the strength of the magnetic flux unnecessarily radiated from the first magnet section (1410) toward the second magnet section (1420) can be detected. Conversely, by using the first lens sensors (H5 to H8) installed in the first coil section (1710), the strength of the magnetic flux unnecessarily radiated from the second magnet section (1420) toward the first magnet section (1410) can be detected.

[0184] FIG. 12 is a diagram showing the crosstalk of an actuator according to an embodiment of the present invention, where (a) shows the change in magnetic flux density with respect to the amount of variation of the magnet part, and (b) shows the change in magnetic flux density with respect to the decrease in the distance between lenses.

[0185] Referring to FIG. 12 (a), the left side shows the simulation result of a conventional actuator and the right side shows the simulation result of an actuator according to an embodiment, where the horizontal axis represents the amount of movement of the magnet part in mm and the vertical axis represents the amount of interference of magnetic flux density in μT.

[0186] It can be confirmed that in a conventional actuator, the maximum variation in magnetic flux density is 0.9 μT when the displacement is 5.3 mm, and in an actuator according to the embodiment, the maximum variation in magnetic flux density is 0.59 μT when the displacement is 5.9 mm.

[0187] Referring to FIG. 12(b), the left side shows the simulation result of a conventional actuator and the right side shows the simulation result of an actuator according to an embodiment, where the horizontal axis represents the reduced distance between lenses in mm and the vertical axis represents the maximum variation amount of magnetic flux density in μT.

[0188] Since the maximum variation in a conventional actuator is 0.9 μT when the reduction distance between lenses is 0 mm, it can be confirmed that in the actuator according to the embodiment, the reduction distance between lenses is 1.1 mm when the maximum variation is 0.9 μT. That is, in the actuator according to the embodiment, it can be confirmed that the amount of crosstalk when the reduction distance between lenses is reduced by 1.1 mm is the same as the crosstalk of the conventional actuator. Therefore, the width of the actuator in the x-direction can be reduced by 1.1 mm.

[0189] A conventional actuator has a width of 15.44 mm in the x direction, a height of 6.15 mm in the y direction, and a length of 21.68 mm in the z direction, but a camera actuator according to the embodiment has a width of 14.34 mm in the x direction, a height of 6.15 mm in the y direction, and a length of 21.68 mm in the z direction, so the width in the x direction can be reduced by 1.1 mm.

[0190] In this way, by reducing the size of the camera actuator so that the width in the x-direction is reduced by about 7%, it is possible to meet the miniaturization design requirements of mobile electronic devices in which the camera actuator is employed.

[0191] Although the present invention has been described above, those skilled in the art will recognize that the invention may be implemented in other forms while maintaining the technical concept and essential features of the invention.

[0192] The scope of the present invention shall be defined by the claims, but all modifications or variations derived from configurations directly derived from the descriptions in the claims, as well as configurations equivalent thereto, shall be interpreted as being included within the scope of the present invention.

Claims

1. Housing; A first lens assembly and a second lens assembly that move along the optical axis direction within the housing; A first M-yoke and a second M-yoke, each fixed to the first lens assembly and the second lens assembly, respectively; A first magnet part and a second magnet part attached to the flat plates of the first M-yoke and the second M-yoke, respectively; and It includes a first coil part and a second coil part fixed to the above housing and driving the first magnet part and the second magnet part, respectively, and A camera actuator in which the first magnet part and the second magnet part have a plurality of magnets arranged in a Halbach array, and the direction of their magnetic flux is perpendicular to the optical axis.

2. In Paragraph 1, A camera actuator characterized in that the first M-yoke or the second M-yoke comprises a flat plate contacting the lower surface of the magnet part and a side reinforcing part contacting the side of the magnet part, wherein the upper end of the side reinforcing part coincides with the upper surface of the magnet part.

3. In Paragraph 2, A camera actuator, wherein the first M-yoke or the second M-yoke further comprises an additional reinforcing member that contacts the front and rear surfaces of the magnet part.

4. In Paragraph 1, A camera actuator further comprising a first C-yoke and a second C-yoke installed on the outer surface of each of the first coil portion and the second coil portion.

5. In any one of paragraphs 1 through 4, A camera actuator in which the above M-yoke or the above C-yoke is formed of CoFe alloy.

6. In Paragraph 5, A camera actuator in which the Co content of the above CoFe alloy is 27% or more by weight.

7. In any one of paragraphs 1 through 4, A camera actuator, wherein the above M-yoke or the above C-yoke is formed of silicon steel plate.

8. In Paragraph 7, A camera actuator in which the Si content of the silicon steel sheet is within the range of 1% to 5% by weight.

9. In Paragraph 1, The above first M-yoke and the above second M-yoke are a camera actuator that opens one side facing inward perpendicular to the optical axis and shields the other side.

10. In Paragraph 1, A camera actuator characterized in that at least one of the above magnets has polarity divided diagonally.

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