Actuator for camera

Abstract

An actuator for a camera according to one embodiment of the present invention comprises: a first frame moving in a plane direction perpendicular to an optical axis; first and second magnets installed on the first frame to form a right angle; a second frame supporting the movement of the first frame; a first yoke made of a magnetic material, including n (where n is a natural number of 2 or more) parts spaced apart from each other along the longitudinal direction of the first magnet, and provided on the second frame to face the first magnet; and a second yoke made of a magnetic material and provided on the second frame to face the second magnet, wherein a separation distance between one of the n parts and the first magnet is different from a separation distance between another one of the n parts and the first magnet.

Description

Actuator for camera

[0001] The present invention relates to an actuator for a camera, and more specifically, to an actuator for a camera that can further improve the driving precision of OIS by effectively suppressing the rotation of the carrier.

[0002] As hardware technology for image processing advances and user demand for video recording increases, features such as autofocus (AF) and optical image stabilization (OIS) are being implemented not only in standalone camera devices but also in camera modules mounted on mobile terminals such as mobile phones and smartphones.

[0003] The autofocus function refers to a feature that enables a sharp image to be generated on an image sensor (CMOS, CCD, etc.) located behind the lens by linearly moving a carrier equipped with a lens or similar device along the optical axis to adjust the focal distance to the subject.

[0004] Image stabilization refers to a function that improves image clarity by adaptively moving the carrier equipped with the lens (or image sensor) in a direction that compensates for shake caused by hand tremor in the event of shaking of the lens or image sensor.

[0005] One of the representative methods for implementing autofocus or OIS functions is to move a moving body by utilizing the magnetic force (electromagnetic force) between a magnet (coil) installed on a moving body (carrier) and a coil (magnet) installed on a stationary body (housing, base, or other types of carriers, etc.). In this case, a ball may be placed between the moving body and the stationary body to guide the movement of the moving body.

[0006] OIS corrects shaking by moving a moving body equipped with a lens or image sensor in the first direction or / and a second direction, which are two axes on a plane perpendicular to the optical axis, relative to a relative fixed body.

[0007] In the case of conventional actuators, a structure is mainly applied in which an intermediate moving body (middle guide) is applied between a moving body and a stationary body for independent movement in the first and second directions, and balls are placed between the moving body and the intermediate moving body, and between the intermediate moving body and the stationary body, respectively.

[0008] In the case of such conventional actuators, the structure consists of a stacked moving body, an intermediate moving body, and a stationary body, and since balls are placed between them, the height increases with respect to the optical axis direction.

[0009] Since camera actuators are installed in an upright position on the main board of a mobile terminal such as a smartphone, an increase in the height of the actuator implies an increase in the thickness of the mobile terminal; therefore, conventional actuators have the problem of failing to meet the trend of slimming down mobile terminals and having low space utilization.

[0010] To resolve these problems, a structure is disclosed that moves a moving body in a plane perpendicular to the optical axis with respect to a relative fixed body without an intermediate moving body. An actuator with this structure has the advantage of being able to reduce the height of the actuator because it only requires placing balls between the moving body and the relative fixed body, without stacking two types of balls that guide movement in each direction vertically.

[0011] However, in the case of such actuators, since there is no structure to guide the linear movement of the moving body, the moving body may rotate due to internal or external causes. Since OIS is implemented by linearly moving the moving body, on which the lens or the like is mounted, in a combined direction of the first and second directions, the driving precision of OIS may be degraded when the moving body rotates in this manner.

[0012] The present invention was devised to solve the aforementioned problems against the background described above, and aims to provide a camera actuator capable of improving the driving precision of OIS for correcting hand shake by effectively suppressing the rotation of a moving body.

[0013] Other objects and advantages of the present invention may be understood from the description below and will become more clearly known from the embodiments of the present invention. Furthermore, the objects and advantages of the present invention may be realized by the configurations set forth in the claims and combinations thereof.

[0014] An actuator for a camera according to one embodiment of the present invention for achieving the above objective may include: a first frame that moves in a planar direction perpendicular to the optical axis; first and second magnets installed on the first frame to form a right angle; a second frame that supports the movement of the first frame; a first yoke made of a magnetic material provided on the second frame to face the first magnet, comprising n (n is a natural number greater than or equal to 2) parts spaced apart along the length direction of the first magnet; and a second yoke made of a magnetic material provided on the second frame to face the second magnet.

[0015] In this case, the distance between one of the n parts and the first magnet is configured to be different from the distance between another of the n parts and the first magnet.

[0016] Specifically, the first yoke of the present invention may include a first part; and a second part spaced apart from the first part along the longitudinal direction of the first magnet and positioned closer to the second magnet than the first part. In this case, it is preferable that the distance between the second part and the first magnet of the present invention be greater than the distance between the first part and the first magnet.

[0017] According to an embodiment, the first magnet of the present invention may include k (where k is a natural number greater than or equal to 2) stimuli, and in this case, it is preferable that the thickness of the stimulus facing the second part among the k stimuli is smaller than the thickness of the stimulus facing the first part among the k stimuli.

[0018] Additionally, the second yoke of the present invention may include m (where m is a natural number greater than or equal to 2) parts spaced apart along the longitudinal direction of the second magnet. In this case, it is preferable that the spacing between one of the m parts and the second magnet be different from the spacing between another of the m parts and the second magnet.

[0019] Specifically, the second yoke of the present invention may include a third part; and a fourth part spaced apart from the third part along the longitudinal direction of the second magnet and positioned closer to the first magnet than the third part. In this case, it is preferable that the distance between the fourth part and the second magnet be greater than the distance between the third part and the second magnet.

[0020] According to an embodiment, the second magnet of the present invention may include p (where p is a natural number greater than or equal to 2) stimuli, and in this case, the thickness of the stimuli facing the fourth part among the p stimuli may be configured to be smaller than the thickness of the stimuli facing the third part among the p stimuli.

[0021] According to one embodiment of the present invention, since OIS is implemented without the addition of a middle guide or other equivalent additional configuration, the structure and shape of the entire actuator can be configured in a more space-intensive form, which can be further optimized for slimming down mobile terminals.

[0022] According to one embodiment of the present invention, load asymmetry or load bias caused by friction, driving force, return force, etc., can be effectively resolved, and thus rotational behavior of the carrier caused by load asymmetry, etc., can be effectively suppressed.

[0023] According to one embodiment of the present invention, by adjusting the suction force (attraction force) acting between the magnet and the yoke using the distance between the magnet and the yoke, the load asymmetry or load bias of the moving body can be improved, and the degree of design freedom regarding the structure, arrangement, specifications, etc. of internal components can be further increased.

[0024] The following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to facilitate a more effective understanding of the technical concept of the present invention together with the detailed description of the invention provided below; therefore, the present invention should not be interpreted as being limited only to the matters described in these drawings.

[0025] FIGS. 1 and 2 are drawings illustrating the overall configuration of a camera actuator according to a preferred embodiment of the present invention.

[0026] FIG. 3 is a drawing explaining the driving part of the first frame (OIS carrier).

[0027] FIG. 4 is a cross-sectional view illustrating the internal structure of a camera actuator according to one embodiment of the present invention.

[0028] FIG. 5 is a diagram illustrating the interrelationship between a coil, a magnet, and a Hall sensor.

[0029] FIG. 6 is a bottom view illustrating the positional relationship between the magnet and the yoke,

[0030] FIGS. 7 and 8 are drawings illustrating load asymmetry due to OIS driving,

[0031] FIGS. 9 and FIGS. 10 are drawings illustrating a yoke according to an embodiment of the present invention,

[0032] FIG. 11 is a diagram illustrating the relationship between a magnet and a yoke according to one embodiment of the present invention.

[0033] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, and should be interpreted in a meaning and concept consistent with the technical spirit of the present invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0034] Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention; thus, it should be understood that various equivalents and modifications that can replace them may exist at the time of filing this application.

[0035] FIGS. 1 and 2 are drawings illustrating the overall configuration of a camera actuator (hereinafter referred to as 'actuator') (1000) according to the present invention, FIG. 3 is a drawing explaining the configuration for driving the movement of a first frame (200), FIG. 4 is a cross-sectional view illustrating the internal structure of an actuator (1000) according to an embodiment of the present invention, and FIG. 5 is a drawing explaining the interrelationship between a coil, a magnet, and a Hall sensor.

[0036] First, the overall configuration of the present invention and the operational relationship in which OIS and AF are performed will be explained with reference to FIGS. 1 to 5, etc., and detailed information regarding the yoke of the present invention, which performs the function of suppressing rotation and restoring the position of the first frame (200) that is the moving body of OIS, will be described later.

[0037] The actuator (1000) of the present invention illustrated in FIG. 1 and the drawings attached below is an embodiment in which AF and OIS are implemented together, but it is obvious that the actuator (1000) of the present invention can be implemented as an actuator for OIS only depending on the embodiment.

[0038] In addition, the actuator (1000) of the present invention can be implemented as a standalone device, and can also be implemented in the form of a camera module including an image sensor (not shown), etc.

[0039] As illustrated in FIG. 1, etc., the actuator (1000) of the present invention may be configured to include a first frame (200), a second frame (100), and a housing (300).

[0040] The Z-axis direction shown in Fig. 1, etc. is the optical axis direction in which light enters the lens or lens assembly (L), and corresponds to the direction in which the second frame (second carrier) (100) moves back and forth when AF is driven, and the X-axis and Y-axis perpendicular to the optical axis correspond to the direction in which the first frame (first carrier) (200) moves when OIS is driven.

[0041] In the following description of the embodiments of the present invention, one of the two directions perpendicular to the optical axis is referred to as the first direction (Y-axis direction) and the other as the second direction (X-axis direction); however, this is merely an example based on a relative perspective, and it is obvious that either the X-axis direction or the Y-axis direction may be the first direction and the other direction may be the second direction.

[0042] It is self-evident that the axis depicted in the drawing, the term referring to the axis, and terms such as upper, lower, front, rear, vertical, horizontal, etc., described with respect to the axis, are intended merely to provide a relative standard for describing the embodiments of the present invention and are not intended to specify any direction or position based on an absolute standard; furthermore, it is obvious that they may vary relatively depending on the position of the object to be examined, the position or direction of view, etc.

[0043] According to an embodiment, the housing (300) of the present invention may correspond to a basic frame structure that accommodates internal components of an actuator (1000) according to the present invention and may be combined with a case (600) that functions as a shield can.

[0044] The first frame (200) corresponds to an OIS carrier or OIS frame that moves on a plane perpendicular to the optical axis (XY plane based on the drawing) with the second frame (100) or housing (300) as a relative fixed body. When a lens or image sensor is mounted on this first frame (200), the lens (L), etc. moves due to the movement of the first frame (200), thereby implementing an OIS that eliminates external disturbances such as hand shake.

[0045] The first ball (B1) can be placed between the first frame (200) and the second frame (100). If AF is not integrally implemented, the first ball (B1) can be placed between the first frame (200) and, for example, the housing (300), which corresponds to a relative fixed body of the first frame (200).

[0046] In this case, one or more of the second frame (100) and the first frame (200) may include a pocket portion that accommodates the first ball (B1) and prevents the first ball (B1) from escaping to the outside.

[0047] In this manner, when the first ball (B1) is provided, an appropriate gap is maintained between the first frame (200) and the second frame (100), and the first frame (200) can move more flexibly due to the minimized frictional force caused by the moving and rolling of the first ball (B1), thereby further improving noise reduction, driving force minimization, and driving precision.

[0048] The first yoke (700A, see FIG. 6, etc.) of the present invention is a configuration installed on the second frame (100), which is a relative fixed body of the first frame (200), and generates an attractive force with the first magnet (M1) installed on the first frame (200).

[0049] The first yoke (700A) is installed on the second frame (100) to face the first magnet (M1) and is made of a magnetic body or magnetic material that generates an attractive force with the first magnet (M1). The second yoke (700B), made of a magnetic material, is installed on the second frame (100) to face the second magnet (M2) and generates an attractive force with the second magnet (M2).

[0050] As previously described, a first ball (B1) is positioned between the first frame (200), which is the moving body of the OIS, and the second frame (100), which is the relative fixed body of the first frame (200), and an attractive force is applied between the first frame (200) and the second frame (100) by the yoke (700A, 700B) and the magnet (M1, M2).

[0051] Therefore, the first frame (200) is in close contact with the second frame (100) in the direction of the second frame (100) (Z-axis direction based on the drawing) while the first ball (B1) is mediated between the first frame (200) and the second frame (100), so physical contact is maintained between the first frame (200) and the first ball (B1), as well as between the first ball (B1) and the second frame (100).

[0052] The yoke (700A, 700B) may preferably be composed of multiple parts as exemplified in FIG. 6, etc., to increase efficiency such as suppressing rotation of the first frame (200) and restoring its position. Details regarding this will be described later.

[0053] A first magnet (M1) facing the first coil section (C1) and a second magnet (M2) facing the second coil section (C2) may be installed in the first frame (200). For directional control, it is preferable that the first and second magnets (M1, M2) be arranged at right angles to each other, and depending on the embodiment, each of the first and second magnets (M1, M2) may be composed of one or more magnets.

[0054] When power of an appropriate size and direction is supplied to the first coil part (C1) through the control of the first drive drive (D1), a magnetic force (electromagnetic force) is generated between the first magnet (M1) installed on the first frame (100) and the first coil part (C1), and using this generated magnetic force as a driving force, the first frame (200) moves in the first direction (Y-axis direction) relative to the second frame (100) or the housing (300). Through this movement control, external disturbances such as hand tremors in the Y-axis direction are corrected.

[0055] When power of an appropriate size and direction is supplied to the second coil section (C2) through the control of the second drive drive (D2), a magnetic force (electromagnetic force) is generated between the second magnet (M2) installed on the first frame (200) and the second coil section (C2), and using this generated magnetic force as a driving force, the first frame (200) moves the second frame (100) or the housing (300) in the second direction (X-axis direction) relative to the fixed body. Through this movement control, X-axis direction OIS is implemented.

[0056] According to the embodiment, position sensors (H1, H2) that detect the position, direction of movement, size of movement, etc. of the first frame (200) may be further included. When the position sensors detect the position, etc. of the first frame (200) and transmit a corresponding signal to the drive drive (control unit), the drive drive controls the supply of power of a size and direction corresponding to the signal to the coil unit.

[0057] The above position sensor can be implemented as a Hall sensor that uses the Hall effect to detect changes in the magnitude and / or direction of the magnetic field of a magnet present within the detection area and outputs an electrical signal accordingly.

[0058] The first Hall sensor (H1) of the present invention is configured to detect the magnitude of a magnetic field that changes according to the position of the first magnet (M1) and to output a corresponding signal.

[0059] When the first Hall sensor (H1) detects the position of the first magnet (M1) installed on the first frame (200) and outputs a corresponding signal to the first drive drive (D1), the first drive drive (D1) controls the supply of power of a corresponding size and direction to the first coil part (C1).

[0060] The first Hall sensor (H1) may include a plurality of Hall sensors (H1A, H1B) positioned to face the first magnet (M1) at different locations so as to effectively detect the rotational component of the first frame (200).

[0061] As an example of this, FIG. 5 shows a left Hall sensor (H1A) facing the left part (M1A) of the first magnet (M1) (based on FIG. 5) and a right Hall sensor (H1B) facing the right part (M1B) of the first magnet (M1).

[0062] Correspondingly, the first drive drive (D1) may also include a plurality of drive drives (D1A, D1B), and the first coil part (C1) may also include a plurality of coils (C1A, C1B) that are independently controlled by each of the first drive drives (D1A, D1B).

[0063] If the magnitude of the magnetic field detected by multiple first Hall sensors (H1A, H1B) is the same, this means that the first magnet (M1), i.e., the first frame (200), moves linearly or maintains a stationary position.

[0064] In contrast, if the magnitude of the magnetic field detected by multiple first Hall sensors (H1A, H1B) is different from one another, this means that there is a posture deformation due to a rotational component in the first frame (200), that is, the posture of the first frame (200) is not a normal posture.

[0065] When a rotational component of the first frame (200) is detected through detection by multiple first Hall sensors (H1A, H1B), the first drive drive (D1) controls the magnitude and / or direction of the current supplied to each coil included in the first coil section (C1) so that the rotational component of the first frame (200) can be corrected.

[0066] For example, when a rotational component (clockwise) of the first frame (200) is detected, the magnitude of the current supplied to the coil (C1A) located on the left (based on the X-axis direction of FIG. 5) of the first coil part (C1) can be controlled to be relatively larger than the magnitude of the current supplied to the coil (C1B) located on the right, thereby correcting the rotational component of the first frame (200).

[0067] According to an embodiment, the rotational component (clockwise) of the first frame (100) may be corrected by controlling such that a repulsive force is generated between the coil (C1A) provided on the left side of the first coil part (C1) and the first magnet (M1), and an attractive force is generated between the coil (C1B) provided on the right side and the first magnet (M1).

[0068] When the first coil section (C1) includes multiple coils, it may be desirable to configure the current supplied to the coils located on the left and right sides to be controlled by considering the acting force of torque, etc. Based on the embodiment illustrated in the drawings below, the coil located on the left side of the first coil section (C1) is referred to as the first coil (C1A), and the coil located on the right side is referred to as the second coil (C1B).

[0069] In order to more effectively correct the rotational component of the first frame (200), it is preferable that the first coil (C1A), which is one of the first coil parts (C1), is controlled by the first Hall sensor (H1A) and the first drive (D1A), and the second coil (C1B), which is the other of the first coil parts (C1), is controlled by the first Hall sensor (H1B) and the first drive (D1B). That is, it is preferable that the first coil (C1A) and the second coil (C1B) be configured to be driven or controlled independently.

[0070] The second Hall sensor (H2) of the present invention is configured to detect the magnitude of a magnetic field that changes according to the position of the second magnet (M2), etc., and to output a corresponding signal. Since the specific details of the second Hall sensor (H2) may correspond to part or all of the first Hall sensor (H1) described above, a detailed description thereof is omitted.

[0071] In order to increase the precision of detecting the rotational component of the first frame (200) or to supplement or complement the detection of the rotational component of the first frame (200), the second Hall sensor (H2) may also be implemented as a plurality of Hall sensors, similar to the first Hall sensor (H1). According to the embodiment, as illustrated in the drawing, the detection of the rotational component of the first frame (200) may be configured to be implemented in either the first Hall sensor (H1) or the second Hall sensor (H2).

[0072] When the second Hall sensor (H2) detects the position of the second magnet (M2) installed on the first frame (200) and outputs a corresponding signal to the second drive drive (D2), the second drive drive (D2) can control the supply of a current of a corresponding magnitude and direction to the second coil part (C2) in a cyclic manner.

[0073] As illustrated in the drawing, it is preferable for the second coil section (C2) to include multiple coils to increase driving efficiency and driving force. For relative distinction of the coils, the coils included in the second coil section (C2) are referred to as the third coil (C2A) and the fourth coil (C2B).

[0074] According to the embodiment of the present invention, the Y-axis direction OIS of the first frame (200) is implemented by the first coil part (C1) and the first magnet (M1), and the X-axis direction OIS of the first frame (200) is implemented by the second coil part (C2) and the second magnet (M2), and the rotation correction of the first frame (200) is implemented through independent control of the first coil (C1A) and the second coil (C1B) of the first coil part (C1), and the driving force of the X-axis direction OIS can be increased through a plurality of coils.

[0075] When the third coil (C2A) and the fourth coil (C2B) included in the second coil section (C2) are controlled to be interconnected, that is, so that the driving force has the same directionality, it is desirable for the second coil section (C2) to be composed of multiple coils within the design's permissible range.

[0076] Since a specific area at both ends of the magnet corresponds to a variable region where the magnitude of the magnetic field changes significantly, it is difficult to implement drive control linearly. Therefore, if individual coils are configured such that the size or width facing the magnet is differentiated, the variable region of the magnet facing the individual coil can be excluded as much as possible, thereby improving both driving force enhancement and linear control characteristics.

[0077] When the second coil section (C2) includes multiple coils, it is preferable that the second Hall sensor (H2) facing the second magnet (M2) be positioned to face the middle part of the second magnet (M2).

[0078] In the case of such an embodiment of the present invention, even if the first frame (200) rotates due to internal or external factors, the second Hall sensor (H2) can be positioned to face the area of ​​the second magnet (M2) where the change in position or orientation is relatively smallest. Therefore, the second Hall sensor (H2) can detect the magnetic field of the second magnet (M2) in an environment where the influence of the rotation of the first frame (200) is minimized, thereby improving the driving precision of rotation detection and rotation correction.

[0079] The second frame (100) corresponds to a moving body that implements AF by moving the housing (300) in the direction of the optical axis (Z-axis direction) as a relative fixed body.

[0080] In order to guide the movement of the second frame (100) in the direction of the optical axis, one or more of the second frame (100) and the housing (300) may be provided with a rail (R) having a shape extended in the direction of the optical axis and on which the second ball (B2) is placed.

[0081] The above rail (R) may be arranged side by side on both sides of the third magnet (M3) as illustrated in the drawing to stably guide the movement of the second frame (100), and may be arranged facing each other on the second frame (100) and the housing (300) respectively so that linear guiding of the second frame (100) and the second ball (B2) is effectively achieved.

[0082] A third magnet (M3) is installed in the second frame (100) and faces an AF coil (C3) installed in the housing (300). When current of appropriate magnitude and direction is supplied to the AF coil (C3) through detection by the AF Hall sensor (H3) and control by the AF drive (D3), an electromagnetic force (magnetic force) is generated between the AF coil (C3) and the third magnet (M3), and the second frame (100) moves in the direction of the optical axis using this electromagnetic force as a driving force.

[0083] When the second frame (100) moves in the direction of the optical axis, the first frame (200), on which the lens, etc. is mounted, also moves in the direction of the optical axis together with the second frame (100).

[0084] When the second frame (100) moves back and forth in the direction of the optical axis in this way, the distance between the lens and an image sensor (not shown), such as a CCD (Charged-coupled Device) or CMOS (Complementary Metal-oxide Semiconductor), which is provided at the rear end (relative to the direction of the optical axis) of the actuator (1000), is adjusted, thereby implementing an autofocus function or a zoom function.

[0085] The actuator (1000) of the present invention may include a third magnet (M3) and a yoke plate (500) that generates a force, provided in a housing (300).

[0086] As the second frame (100) mediated by the second ball (B2) is pulled in the direction of the housing (300) (in the Y-axis direction according to the drawing) by the attractive force between the yoke plate (500) and the third magnet (M3), point contact between the second ball (B2) and the second frame (100) and between the second ball (B2) and the housing (300) is continuously maintained.

[0087] To effectively implement linear guiding, it is preferable that the second ball (B2) be arranged in such a way that a portion thereof is received in a rail (R) provided in one or more of the second frame (100) and the housing (300).

[0088] In this way, when the second ball (B2) is positioned between the second frame (100) and the housing (300), the second frame (100) can move more flexibly linearly with minimized frictional force caused by the moving, rolling, etc. of the second ball (B2).

[0089] It is preferable that the circuit board (400), on which coils (C1, C2, C3) and Hall sensors (H1, H2, H3) are mounted, be provided in a housing (300) located at the outermost side of the actuator (1000) for interfacing with an external device.

[0090] The first drive (D1A, D1B) may be implemented as independent electronic components or devices, but it may also be implemented in the form of a single electronic component (chip) integrated with the first Hall sensor (H1A, H1B) through an SOC (System On Chip). In this regard, the drawing shows the first Hall sensor (H1A) and the first drive (D1A), and the first Hall sensor (H1B) and the first drive (D1B) in the same configuration. The second drive (D2) and / or the AF drive (D3) are also like this.

[0091] The drive unit may be provided in the same number as the individual Hall sensors and implemented as a single chip with the individual Hall sensors, but depending on the embodiment, it may not be provided in the same number as the individual Hall sensors through channel adjustment for electrical connection with the Hall sensors and may be implemented as a single chip with some of the individual Hall sensors.

[0092]

[0093] FIG. 6 is a bottom view illustrating the positional relationship between magnets (M1, M2) and yokes (700A, 700B), FIG. 7 and FIG. 8 are drawings illustrating load asymmetry due to OIS driving, and FIG. 9 and FIG. 10 are drawings illustrating yokes (700A, 700B) according to an embodiment of the present invention.

[0094] Hereinafter, with reference to the attached drawings, etc., the specific functions and structures of the yoke (700A, 700B) according to one embodiment of the present invention will be described in detail.

[0095] The yoke (700A, 700B) of the present invention is a configuration installed on the second frame (100), which is a relative fixed body of the first frame (200), and generates an attractive force with the magnet (M1, M2) installed on the first frame (200).

[0096] Specifically, the yoke may include a first yoke (700A) and a second yoke (700B). The first yoke (700A) is installed on the second frame (100) to face the first magnet (M1) and is made of a magnetic body or magnetic material that generates an attractive force with the first magnet (M1). The second yoke (700B), made of a magnetic material, is installed on the second frame (100) to face the second magnet (M2) and generates an attractive force with the second magnet (M2).

[0097] Hereinafter, the yoke facing the first magnet (M1) is referred to as the first yoke (700A) and the yoke facing the second magnet (M2) is referred to as the second yoke (700B); however, since this is merely a relative distinction of the yokes to increase the efficiency of explanation and understanding, the first yoke (700A) may be either the yoke facing the first magnet (M1) or the yoke facing the second magnet (M2).

[0098] The first yoke (700A) may include n (n is a natural number greater than or equal to 2) parts spaced apart along the longitudinal direction (X-axis direction based on the drawing) of the first magnet (M1). As an example thereof, the drawing shows a first yoke (700A) including a first part (710A) and a second part (720A).

[0099] In this regard, the second yoke (700B) may also include m (m is a natural number greater than or equal to 2) parts spaced apart along the longitudinal direction (Y-axis direction based on the drawing) of the second magnet (M2). As an example thereof, the drawing shows a second yoke (700B) including a third part (720B) and a fourth part (710B).

[0100] In this way, when the yoke (700A, 700B) is composed of multiple parts, the positional acting force of the torque can be organically reflected, thereby enabling more effective suppression of rotation and restoration of the correct position of the first frame (200).

[0101] The first part (710A) and the second part (720A) of the first yoke (700A) both face the first magnet (M1) and are installed on the relative fixed body (second frame (100), etc.) of the first frame (200) in a manner spaced apart from each other along the longitudinal direction of the first magnet (M1) as shown in the drawing.

[0102] The first yoke (700A) may be provided on the second frame (100) by insert injection molding into the second frame (100), and for the efficiency of the molding process, the first part (710A) of the first yoke (700A) and the second part (720A) of the first yoke (700A) may be interconnected. The second yoke (700B) is also like this.

[0103] For relative distinction, the part positioned closer to the second magnet (M2) among the multiple parts of the first yoke (700A) is referred to as the second part (720A).

[0104] The third part (720B) and the fourth part (710B) of the second yoke (700B) both face the second magnet (M2) and are installed on the relative fixed body (second frame (100), etc.) of the first frame (200) in a form spaced apart from each other along the longitudinal direction of the second magnet (M2) as shown in the drawing.

[0105] For relative distinction, among the multiple parts included in the second yoke (700B), the part positioned closer to the first magnet (M1) is referred to as the fourth part (710B).

[0106] According to this relative distinction, among the first part (710A) of the first yoke (700A), the second part (720A) of the first yoke (700A), the third part (720B) of the second yoke (700B), and the fourth part (710B) of the second yoke (700B), the second and fourth parts (720A, 710B) correspond to parts placed in an area where the first magnet (M1) and the second magnet (M2) are close to each other (hereinafter referred to as the "close area").

[0107] The first magnet (M1) and the second magnet (M2) are provided on the first frame (200) so that the first frame (200) moves in a combined direction of the first direction (Y-axis direction) and the second direction (X-axis direction), and are provided on the outer part of the first frame (200) so as to be perpendicular to each other.

[0108] Therefore, the center of gravity of the first frame (200) on which the first and second magnets (M2) are installed does not coincide with the physical center based on the shape of the first frame (200). Specifically, based on the drawing (Fig. 5), the upper right area is the close proximity area where the first magnet (M1) and the second magnet (M2) are close, so the center of gravity of the first frame (200) is biased in this direction.

[0109] Since Fig. 6 is a bottom view of the actuator (1000) shown in Fig. 5, when based on Fig. 6, the upper left area becomes the proximity area where the first magnet (M1) and the second magnet (M2) are close together.

[0110] As the center of gravity is biased in this way, when a driving force or rotational return force is applied in the first direction or / and the second direction, loads such as frictional force, driving force, and return force are generated in an asymmetrical or biased form, and rotational behavior of the first frame (100) may occur due to these biased loads.

[0111] When a driving force is generated between the second magnet (M2) and the second coil part (C2), the first frame (200) moves back and forth in the second direction (X-axis direction) as shown in FIG. 7.

[0112] In this way, when the first frame (200) moves in the second direction, the upper area (based on FIG. 7), "SECTION1," becomes an area where the force exerted by the first part (710A) of the first yoke (700A), the second part (720A) of the first yoke (700A), and the fourth part (710B) of the second yoke (700B) acts, and the lower area, "SECTION2," becomes an area where the force exerted by the third part (720B) of the second yoke (700B) acts.

[0113] In other words, based on the embodiment illustrated in the drawing, since three yokes are arranged in "SECTION1" and one yoke in "SECTION2," the attractive force acting in "SECTION1" becomes greater than the attractive force acting in "SECTION2." This asymmetry or bias in attractive force acts as load asymmetry or load bias in relation to the OIS driving force.

[0114] Therefore, when the first frame (200), which is an OIS moving body, is driven to move linearly in the X-axis direction, movement (moving) by a rotational component occurs in the first frame (200) due to this load asymmetry. Specifically, when the first frame (200) moves in the negative X-axis direction (right direction based on FIG. 7), a counterclockwise rotational component is involved, and when the first frame (200) moves in the positive X-axis direction (left direction based on FIG. 7), a clockwise rotational component is involved.

[0115] When a driving force is generated between the first magnet (M1) and the first coil part (C1), the first frame (200) moves back and forth in the first direction (Y-axis direction) as shown in FIG. 8.

[0116] When the first frame (200) is driven to move linearly in the Y-axis direction, the force exerted by the second part (720A) of the first yoke (700A), the third part (720B) of the second yoke (700B), and the fourth part (710B) of the second yoke (700B) acts on "SECTION3", and only the force exerted by the first part (710A) of the first yoke (700A) acts on "SECTION4".

[0117] Therefore, when the first frame (200) moves in the negative Y-axis direction (upward direction based on FIG. 7), a counterclockwise rotation component is involved, and when the first frame (200) moves in the positive Y-axis direction (downward direction based on FIG. 7), a clockwise rotation component is involved.

[0118] The area where "SECTION1" and "SECTION3" overlap corresponds to the proximity area where the first magnet (M1) and the second magnet (M2) are close to each other.

[0119] In order to effectively resolve these problems, the distance between one of the n parts included in the first yoke (700A) and the first magnet (M1) is configured to be different from the distance between another of the n parts and the first magnet (M1).

[0120] In this way, if the spacing between the parts included in the first yoke (700A) and the first magnet (M1) is configured to be partially or entirely different, the attractive force (suction force) between the parts included in the first yoke (700A) and the first magnet (M1) can be configured individually differently, thereby improving the load asymmetry of the first frame (200).

[0121] Through this, overall load balance or load symmetry of the first frame (200) is achieved, so that the first frame (200) can be induced to move linearly in the X-axis or Y-axis direction without rotating. The second yoke (700B) including m parts is also like this.

[0122] As previously seen in FIGS. 7 and 8, the second part (720A) of the first yoke (700A) and the fourth part (710B) of the second yoke (700B) are parts located in both SECTION 1, where a relatively large load is applied in the X-axis direction movement, and SECTION 3, where a relatively large load is applied in the Y-axis direction movement.

[0123] Therefore, it is desirable that the separation distance (G2, see FIG. 9 and FIG. 10) between the second part (720A) and the first magnet (M1) be greater than the separation distance (G1) between the first part (710A) and the first magnet (M1) (G2 > G1), that is, that a relatively small attractive force acts on the second part (720A).

[0124] In this regard, it is desirable that the separation distance (G4) between the fourth part (710B) and the second magnet (M2) be greater than the separation distance (G3) between the third part (720B) and the second magnet (M2) (G4 > G3), that is, that a relatively small attractive force acts on the fourth part (710B).

[0125] As previously defined, among the multiple parts included in the first yoke (700A), the part positioned closer to the second magnet (M2) is the second part (720A), and among the multiple parts included in the second yoke (700B), the part positioned closer to the first magnet (M1) is the fourth part (710B).

[0126] In the case of such an embodiment of the present invention, the center of gravity can be improved in both X-axis and Y-axis movement, and the force (load) in the area where the force (load) acts relatively large can be reduced, thereby enabling load balance or load symmetry of the entire first frame (200).

[0127]

[0128] FIG. 11 is a diagram illustrating the relationship between a magnet (M1) and a yoke (700A) according to an embodiment of the present invention. Below, an embodiment of the present invention is described that improves load asymmetry or load bias by adjusting specifications such as the magnetic pole thickness of the magnet.

[0129] The first magnet (M1) may include k (k is a natural number greater than or equal to 2) magnetic poles facing the first coil portion (C1).

[0130] Since the first magnet (M1) is configured to generate a driving force in the first direction (Y-axis direction) in relation to the first coil part (C1), the multiple magnetic poles of the first magnet (M1) can be implemented not only by physically configuring multiple magnets of a single magnet, but also by arranging multiple magnets having their own individual magnetic poles.

[0131] In this regard, if multiple stimuli of the first magnet (M1) face the first coil part (C1), it should be interpreted that the physical number of the first magnet (M1) can be configured in various ways depending on the embodiment.

[0132] Figure 11 illustrates a first magnet (M1) having three stimuli (P1, P3, and P2) in the direction from left to right (based on the positive X-axis direction) as an example of this.

[0133] Hereinafter, to enhance the efficiency of explanation and understanding, among the stimuli of the first magnet (M1), the stimulus located in the proximity region, which is the area where the first magnet (M1) and the second magnet (M2) are close to each other, is referred to as the second stimulus (P2), and the stimulus located in the area relatively far from the second magnet (M2) is referred to as the first stimulus (P1).

[0134] As shown in the previously referenced drawing (e.g., FIG. 9), if the stimuli of the first and second magnets (M1, M2) are each composed of two, the stimuli of the first magnet (M1) located to the left with respect to the X-axis direction become the first stimuli (P1), and the stimuli located to the right of the first stimuli (P1) become the second stimuli (P2). In the case of the second magnet (M2), the stimuli located upward with respect to the Y-axis direction become the second stimuli (P2), and the stimuli located downward become the first stimuli (P1).

[0135] Although the drawing shows first and second magnets (M1, M2) having the same number of stimuli, depending on the embodiment, the number of stimuli of the first magnet (M1) and the number of stimuli of the second magnet (M2) may not be the same.

[0136] When examining the positional relationship between the first yoke (700A) and the first magnet (M1), the first stimulus (P1) of the first magnet (M1) faces the first part (710A) of the first yoke (700A), and the second stimulus (P2) of the first magnet (M1) faces the second part (720A) of the first yoke (700A).

[0137] The thickness (or size, etc.) (T2) of the second stimulus (P2) facing the second part (720A) of the first yoke (700A) among the stimuli of the first magnet (M1) is smaller than the thickness (or size, etc.) (T1) of the first stimulus (P1) facing the first part (710A) of the first yoke (700A). <T1) 구성되는 것이 바람직하다.

[0138] In the case of such an embodiment of the present invention, the attractive force (load) between the first magnet (M1) and the first yoke (700A), specifically between the first magnet (M1) and the second part (720A) of the first yoke (700A), can be reduced in the proximity area where the load acts relatively heavily (the area where SECTION1 and SECTION3 overlap), thereby improving the load asymmetry of the first frame (200) overall.

[0139] When the first magnet (M1) is configured to include multiple individual magnets, a method of differentiating the attractive force by varying the material characteristics of the magnet facing the second part (720A) and the magnet facing the first part (710A) may also be applied.

[0140] In a corresponding view, when the second magnet (M2) is configured to include p (where p is a natural number greater than or equal to 2) stimuli, the thickness of the stimuli facing the fourth part (710B) of the second yoke (700B) among the p stimuli may be configured to be smaller than the thickness of the stimuli facing the third part (720B).

[0141] Since the magnitude of the driving force may decrease if the thickness of the stimulus, etc., is reduced, the physical specifications of the coil facing the small-thickness stimulus or the magnitude of the current supplied to the coil may be configured to be adjusted so that a driving force of the designed size can be generated in this case.

[0142]

[0143] Although the present invention has been described above by limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical spirit of the present invention and the equivalent scope of the claims described below by those skilled in the art to which the present invention belongs.

[0144] In the description of the present invention described above, modifiers such as "first," "second," etc., are merely instrumental conceptual terms used to relatively distinguish components from one another, and should be interpreted as not being used to indicate a specific order, priority, etc.

[0145] Although the drawings and other accompanying materials for the description of the present invention and the illustration of embodiments thereof may be depicted in a somewhat exaggerated form to emphasize or highlight the technical content according to the present invention, it should be interpreted as obvious to a person skilled in the art that various modified application examples are possible by considering the aforementioned descriptions and the details illustrated in the drawings.

Claims

1. A first frame moving in a plane direction perpendicular to the optical axis; First and second magnets installed on the first frame to form a right angle; A second frame that supports the movement of the first frame; A first yoke made of a magnetic material provided on the second frame to face the first magnet, comprising n (where n is a natural number greater than or equal to 2) parts spaced apart along the longitudinal direction of the first magnet; and It includes a second yoke made of a magnetic material provided on the second frame to face the second magnet, and An actuator for a camera characterized in that the distance between one of the n parts and the first magnet is different from the distance between another of the n parts and the first magnet.

2. In paragraph 1, the first yoke is, Part 1; and It includes a second part spaced apart from the first part along the longitudinal direction of the first magnet and positioned closer to the second magnet than the first part, An actuator for a camera characterized in that the distance between the second part and the first magnet is greater than the distance between the first part and the first magnet.

3. In paragraph 2, the first magnet is, It includes k (where k is a natural number greater than or equal to 2) stimuli, and An actuator for a camera characterized in that the thickness of the stimulus facing the second part among the k stimuli is smaller than the thickness of the stimulus facing the first part among the k stimuli.

4. In paragraph 1 or 2, the second yoke is, It includes m (m is a natural number greater than or equal to 2) parts spaced apart along the length direction of the second magnet, and An actuator for a camera characterized in that the distance between one of the m parts and the second magnet is different from the distance between another of the m parts and the second magnet.

5. In paragraph 4, the above-mentioned second yoke is, Part 3; and It includes a fourth part spaced apart from the third part along the length direction of the second magnet and positioned closer to the first magnet than the third part, and An actuator for a camera characterized in that the distance between the fourth part and the second magnet is greater than the distance between the third part and the second magnet.

6. In paragraph 5, the second magnet is, It includes p (where p is a natural number greater than or equal to 2) stimuli, and An actuator for a camera characterized in that the thickness of the stimulus facing the fourth part among the p stimuli is smaller than the thickness of the stimulus facing the third part among the p stimuli.

Images