Actuator for a camera

Abstract

An actuator for a camera according to an embodiment of the present application includes a first frame moving in a planar direction perpendicular to an optical axis, at least one first magnet provided to the first frame, at least one second magnet provided to the first frame at a right angle to the at least one first magnet, a second frame supporting movement of the first frame, a plurality of first Hall sensors arranged at different positions from each other in a direction facing the at least one first magnet, and a first magnetic yoke of a magnetic material provided to the second frame in a direction facing the at least one first magnet. In this case, the first magnetic yoke includes a first portion and a second portion having the same size as each other and arranged apart in a length direction of the at least one first magnet.

Description

Technical Field

[0001] This invention relates to an actuator for a camera, and more specifically to an actuator for a camera that can further improve the driving accuracy of OIS by structural improvements to a magnetic yoke that generates attraction with a magnet. Background Technology

[0002] With the development of hardware technology for image processing and the increasing user demand for image shooting, functions such as autofocus (AF) and optical image stabilization (OIS) have been applied to standalone camera devices and camera modules installed in mobile terminals such as mobile phones and smartphones.

[0003] The autofocus function refers to the function of adjusting the focal length of the subject by moving a carrier equipped with a lens or the like along the optical axis, thereby generating a clear image in the image sensor (CMOS, CCD, etc.) located at the back of the lens.

[0004] Optical image stabilization refers to the function of improving image sharpness by adaptively moving the carrier equipped with the lens (or image sensor) in the direction of compensating for the shaking caused by hand tremors in the lens or image sensor.

[0005] One of the typical methods to achieve autofocus or OIS is to place a magnet (coil) on a moving body (carrier) and then place a coil (magnet) on a fixed body (shell, base, or other form of carrier, etc.). By generating a driving force between the coil and the magnet, the moving body is moved along the optical axis or in a direction perpendicular to the optical axis.

[0006] OIS corrects wobbling by causing a moving body equipped with a lens or image sensor to move in the opposite direction relative to a fixed body, along two axes on a plane perpendicular to the optical axis, namely the first direction and / or the second direction.

[0007] In existing actuators, in order to achieve independent movement in the first and second directions, a structure is mainly used in which an intermediate moving body (intermediate guide) is set between the moving body and the fixed body, and balls are arranged between the moving body and the intermediate moving body, and between the intermediate moving body and the fixed body.

[0008] In this existing actuator, the moving body, intermediate moving body and fixed body have a stacked structure, and ball bearings are arranged between them, so the height based on the optical axis direction will increase.

[0009] Camera actuators are mounted vertically on the motherboard of mobile devices such as smartphones. Therefore, increasing the height of the actuator means increasing the thickness of the mobile device. As a result, existing actuators do not conform to the trend of thin and light mobile devices and have low space utilization.

[0010] To address the aforementioned problems, a structure is disclosed that allows a moving body to move along a plane perpendicular to the optical axis with a relative fixed body as a reference without the need for an intermediate moving body. The actuator employing this structure eliminates the need for stacking two types of balls guiding movement in each direction; instead, the balls are simply arranged between the moving body and the relative fixed body, thus offering the advantage of reducing the actuator's height.

[0011] However, in this type of actuator, since there is no structure to guide the linear movement of the moving body, the moving body may rotate under the influence of various factors such as external forces. OIS is achieved by linearly moving a moving body equipped with a lens or the like along a combination of mutually perpendicular first and second directions. Therefore, when the moving body rotates, the driving accuracy of OIS may be reduced.

[0012] To address this issue, a magnetic yoke is placed on a relatively stationary body, which generates an attractive force on a drive magnet located on the moving body. At the end of the OIS drive, this magnetic yoke can also perform a centering function, guiding the moving body back to its initial (default) position.

[0013] In order to suppress rotational components, a magnetic yoke made of magnetic material placed on a relatively fixed body may affect the magnetic field of a magnet such as a magnetic field shield, and therefore may interfere with the magnetic field detection of a Hall sensor that detects the magnetic field of the magnet for OIS control.

[0014] These interference phenomena may be partially mitigated by driver correction algorithms, but since this method is a post-processing approach, it is difficult to be a fundamental solution, and the immediate responsiveness will decrease to the extent that the computational processing should be performed.

[0015] Since OIS continuously causes the moving body to make tiny movements, this response time delay may cause or aggravate posture deviations such as rotation and tilt of the moving body, which may also have an adverse effect on the overall driving accuracy of OIS. Summary of the Invention

[0016] Technical problems to be solved The present invention was made in the context of the above background to solve the aforementioned problems, and its object is to provide an actuator for a camera that can detect the rotational component of a moving body by improving the structure of the magnetic yoke, and perform the correction of the rotational component more quickly and accurately.

[0017] Other objects and advantages of the present invention will be understood from the following description and will become more apparent from the embodiments of the invention. Furthermore, the objects and advantages of the present invention can be achieved through the structures and combinations thereof described in the claims.

[0018] Problem-solving methods A camera actuator according to an embodiment of the present invention for achieving the above-mentioned objectives may include: a first frame movable along a plane perpendicular to the optical axis; at least one first magnet disposed on the first frame; at least one second magnet disposed on the first frame at right angles to the at least one first magnet; a second frame supporting the movement of the first frame; a plurality of first Hall sensors arranged at different positions facing the at least one first magnet; and a first yoke of magnetic material disposed on the second frame facing the at least one first magnet.

[0019] In this case, the first magnetic yoke of the present invention may include a first portion and a second portion arranged spaced apart along the length direction of the at least one first magnet and having the same size as each other.

[0020] According to an embodiment, the first part and the second part of the first magnetic yoke of the present invention can be arranged in a mutually symmetrical manner with the middle part of the length direction of the at least one first magnet as a reference.

[0021] Additionally, an actuator according to an embodiment of the present invention may further include: a second magnetic yoke of magnetic material disposed on the second frame in a manner facing the at least one second magnet. In this case, the second magnetic yoke of the present invention may include a first portion and a second portion arranged spaced apart along the length direction of the at least one second magnet and having the same size as each other.

[0022] Preferably, an actuator according to an embodiment of the present invention may include: a first coil and a second coil arranged facing each other at different positions from the at least one first magnet and driven independently; and a third coil and a fourth coil arranged facing each other at different positions from the at least one second magnet and driven in conjunction.

[0023] Additionally, the actuator according to an embodiment of the present invention may further include: a second Hall sensor facing the at least one second magnet, and the third coil of the present invention may be configured to be larger in size facing the at least one second magnet compared to the fourth coil.

[0024] In this case, the second Hall sensor of the present invention is arranged in the inner space of the third coil, and preferably in a position biased toward the fourth coil.

[0025] According to an embodiment of the invention, the actuator may further include: a third magnet disposed on the second frame; a housing supporting the optical axis movement of the second frame; an AF coil facing the third magnet; a first ball disposed between the first frame and the second frame; and a second ball disposed between the second frame and the housing.

[0026] Invention Effects According to one embodiment of the present invention, since OIS can be achieved without adding intermediate guides or other equivalent additional structures, the overall structure and shape of the actuator can be configured into a more compact form, thereby enabling further optimization to adapt to the thinning and lightening of mobile terminals, etc.

[0027] According to one embodiment of the present invention, since the magnetic yoke used to generate attraction with the magnet is arranged in two or more parts, the rotational component can be effectively suppressed.

[0028] According to one embodiment of the present invention, the segmented magnetic yoke is arranged in a position-matching manner with a plurality of Hall sensors, thereby improving the sensing accuracy of the Hall sensors and the driving accuracy of the driver based thereon.

[0029] According to one embodiment of the present invention, the coil section for correcting the rotational component is composed of multiple independently driven coils, while the coil section for enhancing the driving force is composed of multiple interconnected coils, thereby simultaneously improving the accuracy and efficiency of the basic drive of OIS and the drive for rotational correction. Attached Figure Description

[0030] The following drawings, which are included with this specification, illustrate preferred embodiments of the invention and, together with the detailed description of the invention described below, serve to enable a more effective understanding of the technical concept of the invention. Therefore, the invention should not be construed as being limited to the matters described in such drawings.

[0031] Figure 1 and Figure 2 This is a diagram showing the overall configuration of a camera actuator according to a preferred embodiment of the present invention.

[0032] Figure 3 This is a diagram illustrating the structure that drives the movement of the first frame.

[0033] Figure 4 This is a cross-sectional view showing the internal structure of a camera actuator according to an embodiment of the present invention.

[0034] Figure 5 It is a diagram illustrating the interrelationship between the coil, magnet, and position sensor (Hall sensor).

[0035] Figure 6 This is a diagram illustrating a magnetic yoke according to an embodiment of the present invention.

[0036] Figure 7 It is a bottom view illustrating the positional relationship between the magnet and the yoke.

[0037] Figure 8 This is a diagram illustrating a first magnetic yoke according to an embodiment of the present invention.

[0038] Figure 9 This is a diagram illustrating an embodiment of the second coil and the second Hall sensor according to the present invention.

[0039] Explanation of reference numerals in the attached figures 1000: Actuator 100: Second Frame 200: First Framework 300: Housing 400: Circuit board 500: Magnetic yoke plate 600: Outer casing 700A: First magnetic yoke 710A: The first part of the first magnetic yoke 720A: The second part of the first magnetic yoke 700B: Second yoke 710B: The first part of the second yoke 720B: The second part of the second yoke C1: First coil section C1A, C1B: First coil, second coil C2: Second coil section C2A, C2B: Third coil, fourth coil C3: AF coil M1, M2, M3: First magnet, Second magnet, Third magnet B1: First ball bearing B2: Second ball bearing H1, H2: First Hall sensor, second Hall sensor H3: AF Hall Sensor D1, D2: First driver, second driver D3: AF driver Detailed Implementation The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should not be construed that the terms or words used in this specification and claims have the common or dictionary-defined meanings. Based on the principle that the inventors appropriately define the concepts of the terms in order to best describe their invention, they should be interpreted as meanings and concepts consistent with the technical concept of the present invention.

[0040] Therefore, the embodiments described in this specification and the structures shown in the accompanying drawings are merely the most preferred embodiments of the present invention and do not represent the entire technical concept of the present invention. It is understood that there may be various equivalents and modifications that can replace them for the purposes of this application.

[0041] Figure 1 and Figure 2 This is a diagram showing the overall configuration of a camera actuator (hereinafter referred to as 'actuator') 1000 according to the present invention. Figure 3 This diagram illustrates the structure that drives the movement of the first frame 200. Figure 4 This is a cross-sectional view showing the internal structure of an actuator 1000 according to an embodiment of the present invention. Figure 5 It is a diagram illustrating the relationship between the coil, the magnet, and the position sensor (Hall sensor).

[0042] The following will refer to Figures 1 to 5 First, the overall structure of the present invention and the operational relationship of realizing AF and OIS will be explained. The detailed contents of the magnetic yoke of the present invention, which performs the rotation suppression and positive position restoration functions of the first frame 200 as the moving body of OIS, will be described later.

[0043] Figure 1 The actuator 1000 of the present invention shown in the following figures is an embodiment that simultaneously implements AF and OIS, but it goes without saying that the actuator 1000 of the present invention can be implemented as an actuator for OIS only, depending on the implementation method.

[0044] Furthermore, the actuator 1000 of the present invention can be implemented not only as a standalone device, but also as a camera module including an image sensor (not shown).

[0045] like Figure 1 As shown, the actuator 1000 of the present invention can be configured to include a first frame 200, a second frame 100, and a housing 300.

[0046] Figure 1The Z-axis direction shown is the direction in which light enters the lens or lens assembly L, i.e., the optical axis direction. When driving AF, it is equivalent to the direction in which the second frame (second carrier) 100 moves forward and backward. The X-axis and Y-axis, which are perpendicular to the optical axis, are equivalent to the direction in which the first frame (first carrier) 200 moves when driven by OIS.

[0047] In the following description of 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 only an example based on a relative viewpoint. It is self-evident that either the X-axis direction or the Y-axis direction can be regarded as the first direction and the remaining direction as the second direction.

[0048] The axes shown in the accompanying drawings, the terms used to represent those axes, and the terms such as upper, lower, front, rear, vertical, and horizontal used to describe the axes are only for indicating the relative references used to illustrate the embodiments of the present invention, and are not used to specify the direction or position of a certain party from an absolute reference. They may also vary depending on the position of the object being described, the position or direction of the view, etc., which is self-evident.

[0049] The housing 300 of the present invention corresponds to a basic frame structure that houses the internal components of the actuator 1000 according to the present invention, and according to an embodiment, it can be combined with the outer shell 600 that acts as a shield can.

[0050] The first frame 200 is equivalent to an OIS carrier or OIS frame that moves on a plane perpendicular to the optical axis (the XY plane based on the attached drawing) with the second frame 100 or the housing 300 as a relatively fixed body. When the first frame 200 is equipped with a lens or image sensor, the lens L, etc., moves by moving the first frame 200, thereby achieving OIS that eliminates external interference such as hand tremors.

[0051] The first ball bearing B1 can be arranged between the first frame 200 and the second frame 100. If the AF function is not integrated, the first ball bearing B1 can be arranged between the first frame 200 and a relatively fixed body, such as the housing 300, which corresponds to the first frame 200.

[0052] With the first ball B1 in place, an appropriate gap can be maintained between the first frame 200 and the second frame 100. The first frame 200 can move more smoothly due to the minimized friction caused by the movement and rolling of the first ball B1, thereby further improving noise reduction, driving force minimization, and driving accuracy.

[0053] At least one of the second frame 100 and the first frame 200 may include a receiving groove for accommodating the first ball B1 and preventing the first ball B1 from falling outward.

[0054] The first frame 200 may be provided with a first magnet M1 facing the first coil section C1 and a second magnet M2 facing the second coil section C2. For directional control, the first magnet M1 and the second magnet M2 are preferably arranged perpendicular to each other.

[0055] If a power source of appropriate magnitude and direction is supplied to the first coil section C1 under the control of the first driver D1, a magnetic force (electromagnetic force) is generated between the first magnet M1 disposed on the first frame 200 and the first coil section C1. Using this generated magnetic force as a driving force, the first frame 200 moves along the first direction (Y-axis direction) with the second frame 100 or the housing 300 as a relatively fixed body. Through this movement control, external interferences such as hand tremors in the Y-axis direction component are corrected.

[0056] As illustrated in the attached diagram, the first magnet M1 can be a single magnet or composed of multiple magnets. When the first magnet M1 is composed of multiple magnets, these magnets are preferably arranged in a symmetrical position. The same applies to the second magnet M2.

[0057] If a power source of appropriate magnitude and direction is supplied to the second coil section C2 under the control of the second driver D2, a magnetic force (electromagnetic force) is generated between the second magnet M2 disposed on the first frame 200 and the second coil section C2. Using this generated magnetic force as a driving force, the first frame 200 moves along the second direction (X-axis direction) with the second frame 100 or the housing 300 as a relatively fixed body. Through this movement control, OIS in the X-axis direction is achieved.

[0058] Depending on the implementation, position signal sensors H1 and H2 may also be included for detecting the position, direction of movement, and distance of movement of the first frame 200. If the position sensors detect the position of the first frame 200 and transmit corresponding signals to the driver (control unit), the driver controls the coil unit by supplying power of a corresponding magnitude and direction.

[0059] The aforementioned position sensor can be implemented using a Hall sensor, which utilizes the Hall effect to detect changes in the magnitude and / or direction of the magnetic field of a magnet present in the detection area and outputs a corresponding electrical signal.

[0060] The first Hall sensor (first position sensor) H1 of the present invention is configured to detect the magnitude of the magnetic field, etc., which changes with the position of the first magnet M1, and output a corresponding signal.

[0061] If the first Hall sensor H1 detects the position of the first magnet M1 set on the first frame 200 and outputs a corresponding signal to the first driver D1, the first driver D1 controls the first coil section C1 to supply power of a corresponding magnitude and direction.

[0062] In order to effectively detect the rotational component of the first frame 200, the first Hall sensor H1 may include multiple Hall sensors H1A and H1B, which are arranged facing each other at different positions from the first magnet M1.

[0063] As one example, Figure 5 The left side of the first magnet M1 is shown ( Figure 5 The left Hall sensor H1A faces the first magnet M1 (based on the reference part M1A) and the right Hall sensor H1B faces the right part M1B.

[0064] Correspondingly, the first driver D1 may also include multiple drivers D1A and D1B, and the first coil section C1 may also include multiple coils C1A and C1B that are independently controlled by the first drivers D1A and D1B respectively.

[0065] To distinguish the coils, the coils included in the first coil section C1 are referred to as the first coil C1A and the second coil C1B.

[0066] If the rotational component of the first frame 200 is detected by multiple first Hall sensors H1A and H1B, the first drivers D1A and D1B respectively control the magnitude of the current supplied to the first coil C1A and the second coil C1B to correct the rotational component of the first frame 200.

[0067] If the magnetic field magnitudes detected by multiple first Hall sensors H1A and H1B are the same, it means that the first magnet M1, i.e. the first frame 200, maintains linear movement or remains in the positive position.

[0068] In contrast, if the magnetic field magnitudes detected by multiple first Hall sensors H1A and H1B are different from each other, it means that the first frame 200 has an attitude deformation caused by the rotation component.

[0069] To more effectively correct the rotational component of the first frame 200, the first coil C1A, which is one of the first coil sections C1, is preferably controlled by a first Hall sensor H1A and a first driver D1A, while the second coil C1B, which is the other of the first coil sections C1, is preferably controlled by a first Hall sensor H1B and a first driver D1B. That is, the first coil C1A and the second coil C1B are preferably configured to be driven or controlled independently.

[0070] As described above, when multiple Hall sensors are arranged to face the magnet at different positions, that is, when at least one drive unit of the X-axis OIS and the Y-axis OIS includes multiple Hall sensors arranged at different positions, the characteristics (direction, intensity, etc.) of the magnetic field acting on each Hall sensor are preferably configured to be symmetrical in order to achieve stable driving of the OIS.

[0071] The second Hall sensor (second position sensor) H2 of the present invention is configured to detect the magnitude of the magnetic field, etc., which changes with the position of the second magnet M2, and output a corresponding signal.

[0072] To improve the detection accuracy of the rotation component of the first frame 200, or to supplement or complement the detection of the rotation component of the first frame 200, the second Hall sensor H2 can also be implemented by multiple Hall sensors, just like the first Hall sensor H1. According to the embodiment, as shown in the figure, the detection of the rotation component of the first frame 200 can be implemented by one of the first Hall sensor H1 or the second Hall sensor H2.

[0073] If the second Hall sensor H2 detects the position of the second magnet M2 set in the first frame 200 and outputs a corresponding signal to the second driver D2, the second driver D2 can be controlled by cyclically supplying power of corresponding magnitude and direction to the second coil section C2.

[0074] As illustrated in the attached diagram, in order to improve driving efficiency and driving force, the second coil section C2 preferably includes multiple coils. To distinguish the coils, the coils included in the second coil section C2 are referred to as the third coil C2A and the fourth coil C2B.

[0075] The second frame 100 is equivalent to the moving body that moves along the optical axis (Z-axis direction) with the shell 300 as a relatively fixed body to realize AF.

[0076] In order to guide the second frame 100 to move in the direction of the optical axis, at least one of the second frame 100 and the housing 300 may be provided with a track R having a shape extending in the direction of the optical axis and on which the second ball B2 is arranged.

[0077] A third magnet M3 is disposed on the second frame 100, facing the AF coil C3 disposed on the housing 300. If an appropriate amount and direction of power is supplied to the AF coil C3 through detection by the AF Hall sensor H3 and control by the AF driver D3, an electromagnetic force (magnetic force) is generated between the AF coil C3 and the third magnet M3. Using this electromagnetic force as a driving force, the second frame 100 moves along the optical axis.

[0078] If the second frame 100 moves along the optical axis, the first frame 200, which is equipped with a lens, will also move along the optical axis together with the second frame 100.

[0079] If the second frame 100 moves forward and backward along the optical axis in this way, the distance between the image sensor (not shown) such as CCD (charge-coupled device) or CMOS (complementary metal-oxide-semiconductor) located at the rear end of the actuator 1000 (based on the optical axis) and the lens will be adjusted, thereby realizing the autofocus function or zoom function.

[0080] The actuator 1000 of the present invention may include a magnetic yoke plate 500 disposed in the housing 300 and attracting a third magnet M3.

[0081] Due to the attraction between the magnetic yoke plate 500 and the third magnet M3, the second frame 100, mediated by the second ball B2, is pulled toward the housing 300 (Y-axis direction based on the attached figure), thereby maintaining the point-contact between the second ball B2 and the second frame 100, and between the second ball B2 and the housing 300.

[0082] To achieve linear guidance more effectively, the second ball B2 is preferably arranged such that a portion of it is accommodated in a track R formed on at least one of the second frame 100 and the housing 300.

[0083] When the second ball B2 is disposed on at least one of the second frame 100 and the housing 300, the second frame 100 can move more smoothly and linearly by means of the minimized friction caused by the movement and rolling of the second ball B2.

[0084] For interface with external devices, the circuit board 400 that mounts coils C1, C2, C3, Hall sensors H1, H2, H3, etc. is preferably located on the outermost housing 300 of the actuator 1000.

[0085] The first drivers D1A and D1B can be implemented by independent electronic components or elements, or they can be implemented as a single electronic component (chip) integrated with the first Hall sensors H1A and H1B through a System-on-a-Chip (SoC). For this reason, the first Hall sensor H1A and the first driver D1A, and the first Hall sensor H1B and the first driver D1B are labeled as having the same configuration in the attached figures. The same applies to the second driver D2 and / or the AF driver D3.

[0086] The driver can have the same number of Hall sensors as each Hall sensor and be integrated into a single chip with each Hall sensor. However, depending on the implementation, by adjusting the channels electrically connected to the Hall sensors, it may not have the same number of Hall sensors as each Hall sensor, and may be integrated into a single chip with some of the Hall sensors.

[0087] Figure 6 This is a diagram illustrating magnetic yokes 700A and 700B according to an embodiment of the present invention. Figure 7 This is a bottom view illustrating the positional relationship between magnets M1 and M2 and yokes 700A and 700B. Figure 8 This is a diagram illustrating the first magnetic yoke 700A according to an embodiment of the present invention. Figure 9 This is a diagram illustrating an embodiment of the second coil C2 and the second Hall sensor H2 according to the present invention.

[0088] Hereinafter, with reference to the accompanying drawings and other materials, the specific functions and structures of the magnetic yokes 700A and 700B according to an embodiment of the present invention will be described in detail.

[0089] The magnetic yoke of the present invention is a structure provided in the second frame 100, which is a relatively fixed body of the first frame 200, and generates attraction with the magnets M1 and M2 provided in the first frame 200.

[0090] Specifically, the magnetic yoke may include a first magnetic yoke 700A and a second magnetic yoke 700B. The first magnetic yoke 700A is disposed on the second frame 100 facing the first magnet M1, and is made of a magnetic body or magnetic material that generates attraction with the first magnet M1. The second magnetic yoke 700B, made of a magnetic material, is disposed on the second frame 100 facing the second magnet M2, and generates attraction with the second magnet M2.

[0091] As mentioned above, a first ball bearing B1 is arranged between a first frame 200, which is a moving body of the OIS, and a second frame 100, which is a relatively fixed body of the first frame 200. An attractive force generated by magnetic yokes 700A and 700B and magnets M1 and M2 acts between the first frame 200 and the second frame 100.

[0092] Therefore, with the first frame 200 in a state where the first ball B1 is between the first frame 200 and the second frame 100, it is in close contact along the direction of the second frame 100 (Z-axis direction based on the attached figure), thus maintaining not only physical contact between the first frame 200 and the first ball B1, but also physical contact between the first ball B1 and the second frame 100.

[0093] like Figure 6 As shown, the first magnetic yoke 700A may specifically include a first portion 710A and a second portion 720A arranged spaced apart along the length direction of the first magnet M1 (X-axis direction based on the figure).

[0094] The first part 710A and the second part 720A are separated from the first magnet M1 by a distance G1 along the downward direction of the first magnet M1 (see...). Figure 6 The magnetic body of the second frame 100 is set in a state such that it can shield a portion of the magnetic field of the first magnet M1.

[0095] Therefore, the right side of the first Hall sensor H1 (with) Figure 7 The magnetic field of the first magnet M1 identified by the first Hall sensor H1A (based on the reference) and the first Hall sensor H1B on the left will be affected by the shielding areas formed by the first part 710A and the second part 720A respectively.

[0096] Therefore, when the size, width, position, orientation, and other physical or structural characteristics of the first part 710A and the second part 720A are different from each other, the shielding areas or influences formed by the first part 710A and the second part 720A will also be different from each other, resulting in the magnetic field shape and characteristics detected by the first Hall sensor H1A on the right and the first Hall sensor H1B on the left being different from each other.

[0097] When the magnetic field characteristics detected by so many first Hall sensors H1A and H1B are different from each other, these different magnetic field characteristics need to be continuously reflected in the drive control, thus leading to a decrease in the accuracy of the drive control. In particular, these different magnetic field characteristics will change randomly and dynamically depending on the position of the first magnet M1, etc., so the accuracy of rotation detection and rotation correction based on rotation detection may be significantly reduced.

[0098] Furthermore, if the magnetic field characteristics detected by multiple first Hall sensors H1A and H1B are different from each other, in order to achieve the first direction OIS, that is, in order to generate a driving force between the first magnet M1 and the first coil C1, and to control the magnitude and direction of the current supplied to the first coil C1A and the second coil C1B, it is necessary to reflect different magnetic field characteristics or environments. Therefore, the original driving accuracy of OIS may also be reduced.

[0099] To solve this problem, the first part 710A and the second part 720A of the first magnetic yoke 700A are preferably arranged separately along the length direction of the first magnet M1 and have the same physical characteristics (size, width, length, etc.) (D1=D2, H1=H2, see...). Figure 8 ).

[0100] From a corresponding perspective, the first portion 710A and the second portion 720A of the first magnetic yoke 700A are preferably symmetrical to each other with reference to the midpoint of the length direction of the first magnet M1 (C1=C2, see [reference]). Figure 8 Arranged in a manner similar to ).

[0101] Furthermore, if the length, width, material, thickness, and other specifications of the first part 710A and the second part 720A included in the first magnetic yoke 700A correspond to each other, then the gap G1 between the first part 710A of the first magnetic yoke 700A and the first magnet M1 preferably corresponds to the gap G2 between the second part 720A of the first magnetic yoke 700A and the first magnet M1.

[0102] The second magnetic yoke 700B can also be configured to include a first part 710B and a second part 720B arranged spaced apart along the length of the second magnet M2 and having the same size (width). It is self-evident that the above-described configuration regarding the arrangement, position, and structure of the first magnetic yoke 700A also applies to the second magnetic yoke 700B.

[0103] The first coil C1A and the second coil C1B of the first coil section C1 are preferably arranged facing each other at different positions from the first magnet M1 and driven independently. The third coil C2A and the fourth coil C2B of the second coil section C2 are preferably arranged facing each other at different positions from the second magnet M2 and driven in conjunction.

[0104] According to this embodiment of the present invention, the first direction (Y-axis direction) OIS of the first frame 200 is realized by the first coil part C1 and the first magnet M1, and the second direction (X-axis direction) OIS of the first frame 200 is realized by the second coil part C2 and the second magnet M2. The rotation correction of the first frame 200 can be realized by the independent control of the first coil C1A and the second coil C1B of the first coil part C1, and the driving force of the second direction OIS can be enhanced.

[0105] For example, if a clockwise rotation component of the first frame 200 is detected, the rotation component of the first frame 200 can be corrected by controlling the second coil C1B to apply a current that is relatively greater than the current applied to the first coil C1A.

[0106] Depending on the implementation method, control can also be achieved by generating an attractive force between the first coil C1A and the first magnet M1, and a repulsive force between the second coil C1B and the second magnet M2, thereby controlling the clockwise rotation component of the first frame 200.

[0107] When control is performed by linking multiple coils included in the second coil section C2, i.e., by ensuring that the driving force has the same direction, such as... Figure 9 As illustrated, it is preferable to configure the third coil C2A and the second magnet M2 to be facing each other in different ways as well as the fourth coil C2B and the second magnet M2 to be facing each other in different ways.

[0108] Since specific regions at both ends of the magnet correspond to variable regions with significant variations in magnetic field strength, linear drive control is difficult to achieve. Therefore, by configuring each coil in such a way that the size or width of the coils differs from that of the magnet, the variable regions of the magnet facing each coil can be minimized, thereby simultaneously improving both driving force and linear control characteristics.

[0109] In this case, the second Hall sensor H2 facing the second magnet M2 is preferably as follows: Figure 9 As shown, it is located in the inner space of the third coil C2A and is positioned biased toward the direction in which the fourth coil C2B is located.

[0110] When the present invention is configured in this way, even if the first frame 200 rotates due to external factors, the second Hall sensor H2 can be positioned so that it faces the region of the second magnet M2 where the position or orientation change is minimal. Therefore, the magnetic field of the second magnet M2 can be detected in an environment where the rotation of the first frame 200 has minimal impact, thereby improving the driving accuracy of rotation detection and correction.

[0111] While the present invention has been described above with reference to specific embodiments and accompanying drawings, it is not limited thereto. It is self-evident that those skilled in the art to which this invention pertains can make various modifications and variations within the scope of the technical concept of the invention and the equivalents of the claims described below.

[0112] In the above description of the present invention, modifiers such as first, second, etc. are merely tool concepts used to distinguish between constituent elements, and therefore should be interpreted as not being used to indicate a specific order, priority, etc.

[0113] For the purpose of illustrating the present invention and its embodiments, the accompanying drawings and other illustrations may be shown in a slightly exaggerated form to emphasize or highlight the technical content of the present invention. However, it should be understood that various modifications and applications can be made by those skilled in the art, taking into account the above content and the matters shown in the drawings, etc.

Claims

1. An actuator for a camera, characterized in that, include: The first frame moves along a plane perpendicular to the optical axis; At least one first magnet is disposed in the first frame; At least one second magnet is disposed in the first frame at a right angle to the at least one first magnet; The second frame supports the movement of the first frame; Multiple first Hall sensors are arranged at different positions relative to each other in a manner that faces the at least one first magnet; as well as A first magnetic yoke made of magnetic material is disposed in the second frame in a manner facing the at least one first magnet. The first magnetic yoke includes a first portion and a second portion arranged spaced apart along the length of the at least one first magnet and having the same size as each other.

2. The camera actuator according to claim 1, characterized in that, The first and second portions of the first magnetic yoke are arranged symmetrically with the middle portion of the length direction of the at least one first magnet as a reference.

3. The camera actuator according to claim 1, characterized in that, Also includes: A second magnetic yoke made of magnetic material is disposed in the second frame facing the at least one second magnet. The second magnetic yoke includes a first portion and a second portion arranged spaced apart along the length of the at least one second magnet and having the same size as each other.

4. The camera actuator according to claim 1, characterized in that, include: The first coil and the second coil are arranged facing each other at different positions from the at least one first magnet and are driven independently. as well as The third and fourth coils are arranged and driven in a manner that faces each other at different positions relative to the at least one second magnet.

5. The camera actuator according to claim 4, characterized in that, Also includes: The second Hall sensor is facing the at least one second magnet. The third coil is larger in size relative to the fourth coil, and is positioned opposite the at least one second magnet. The second Hall sensor is arranged in the inner space of the third coil and is positioned biased toward the fourth coil.

6. The camera actuator according to claim 1, characterized in that, Also includes: A third magnet is disposed on the second frame; The housing supports the optical axis movement of the second frame; AF coil, facing the third magnet; The first ball bearing is disposed between the first frame and the second frame; as well as The second ball bearing is disposed between the second frame and the housing.

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