Actuator for camera

Abstract

An actuator for a camera according to an embodiment of the present invention comprises: an OIS carrier that moves in a direction perpendicular to an optical axis direction; an AF carrier that supports the OIS carrier and moves along the optical axis direction together with the OIS carrier; a housing that supports the AF carrier; an OIS magnet provided on the OIS carrier; and an OIS coil provided in the housing so as to face the OIS magnet, the height of the OIS magnet being at least twice the stroke, the stroke being the distance of movement of the AF carrier by AF drive.

Description

Technical Field

[0001] This invention relates to an actuator for a camera, and more specifically to an actuator for a camera that further improves the position control and drive accuracy of OIS. Background Technology

[0002] With the development of hardware technology for image processing and the increasing user demand for image capture, 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 linearly 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 representative methods to achieve autofocus or OIS is to set a magnet (coil) on a moving body (carrier) and set a coil (magnet) on a fixed body (base, shell or other form of carrier, etc.), and then generate a driving force between the coil and the magnet, so that the moving body moves along the optical axis or in a direction perpendicular to the optical axis.

[0006] In the case of a device or actuator that integrates AF and OIS functions, the following structure can be applied: the AF carrier, which moves along the optical axis, is used as a relatively fixed body, and the OIS carrier moves along a direction perpendicular to the optical axis (at least one of the X-axis and Y-axis).

[0007] The AF drive and OIS drive are implemented independently. However, when the AF drive is implemented using the physical structure described above, the OIS carrier moves along the optical axis along with the AF carrier. Therefore, when the AF and OIS are driven together, the OIS carrier does not only move along the X-axis and / or Y-axis, but also moves with a directionality that includes a component along the optical axis (Z-axis).

[0008] The positions of the OIS Hall sensor (which detects the position of the OIS magnet in the X-axis direction) and the OIS coil (which provides driving force to the OIS magnet) are fixed. Therefore, if, as described above, the AF carrier moves vertically (based on the optical axis) due to the AF drive, the positional relationships between the OIS magnet and the OIS Hall sensor, as well as between the OIS magnet and the OIS coil, will change irregularly.

[0009] If the OIS magnet has a movement characteristic that includes a Z-axis component, then not only will the position detection accuracy in each direction used to implement OIS decrease, but the drive control accuracy based on this will also decrease.

[0010] While it is possible to try to solve this problem by applying correction algorithms, it would require complex correction algorithms that can reflect the characteristics of irregular movement. This approach would increase computation time and negatively impact the real-time responsiveness of OIS. Summary of the Invention

[0011] Technical problems to be solved

[0012] The present invention was developed to solve the problems described in the background art above, and its purpose is to provide an optical (camera) actuator that can further improve the accuracy of OIS driving by organically combining the physical layout structure of the components used for OIS (OIS magnet, etc.) with the moving distance (stroke) of the AF carrier.

[0013] Other objects and advantages of the present invention will be understood from the following description and will become clearer through embodiments of the invention. Furthermore, the objects and advantages of the present invention can be achieved through the structures and combinations thereof that appear in the claims.

[0014] Problem-solving methods

[0015] An actuator for a camera according to an embodiment of the present invention for achieving the above-mentioned objectives may include: an OIS carrier that moves in a direction perpendicular to the optical axis; an AF carrier that supports the OIS carrier and moves together with the OIS carrier in the optical axis; a housing that supports the AF carrier; an OIS magnet disposed on the OIS carrier; and an OIS coil disposed on the housing in a manner opposite to the OIS magnet.

[0016] In this case, the height of the OIS magnet is more than twice the travel distance, which is the distance the AF carrier moves due to AF drive.

[0017] Additionally, preferably, when the AF carrier is located in the middle of the stroke, the center position of the OIS magnet is the same as or lower than the center position of the OIS coil.

[0018] Additionally, preferably, when the AF carrier is located in the middle of the stroke, the height deviation between the center position of the OIS magnet and the center position of the OIS coil is less than 30% of the stroke.

[0019] According to an embodiment of the invention, the actuator may further include an OIS Hall sensor that detects the position of the OIS magnet and is disposed in the housing.

[0020] In this case, preferably, when the AF carrier is located in the middle of the travel, the center position of the OIS magnet is the same as or lower than the center position of the OIS Hall sensor.

[0021] Furthermore, preferably, when the AF carrier is located in the middle of the stroke, the height deviation between the center position of the OIS magnet and the center position of the OIS Hall sensor is less than 30% of the stroke.

[0022] According to an embodiment of the invention, the actuator may further include: an AF magnet disposed on the AF carrier opposite to an AF coil disposed on the housing; a magnetic yoke plate disposed on the housing and attracting the AF magnet; and ball bearings disposed between the housing and the AF carrier.

[0023] In this case, preferably, the height of the yoke plate is greater than the sum of the height of the AF magnet and the stroke.

[0024] Invention Effects

[0025] In a preferred embodiment of the present invention, the specifications and position of the OIS magnet are determined by organically reflecting the position, movement distance or range (stroke) of the AF carrier. Therefore, even if the movement of the AF carrier causes the OIS carrier to have irregular motion characteristics, the independent drive of the OIS can be effectively realized.

[0026] According to a preferred embodiment of the present invention, the driving performance of OIS can be more effectively utilized in close-up shooting environments where the accuracy requirements of optical image stabilization are relatively higher. Attached Figure Description

[0027] 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.

[0028] Figure 1 This is a diagram showing the overall structure of an actuator according to a preferred embodiment of the present invention.

[0029] Figure 2 This is a diagram illustrating the detailed structure of an OIS carrier according to a preferred embodiment of the present invention.

[0030] Figure 3 This is a diagram illustrating the detailed structure of an AF carrier according to a preferred embodiment of the present invention.

[0031] Figure 4 and Figure 5 This is a diagram showing the structure of the first ball bearing, the grooved track, and the guide rail.

[0032] Figure 6 It is a diagram illustrating the physical structure of the second carrier moving in all directions relative to the first carrier.

[0033] Figure 7 This is a diagram illustrating another embodiment of the OIS carrier.

[0034] Figure 8 This is a diagram illustrating the internal structure of an actuator according to an embodiment of the present invention.

[0035] Figure 9 Yes Figure 8 The diagram in Part A is described in detail.

[0036] Figure 10 This is a diagram illustrating the relative positions of the OIS magnet, OIS coil, and OIS Hall sensor.

[0037] Figure 11 This is a diagram illustrating the structure of an actuator according to another preferred embodiment of the present invention.

[0038] Figure 12 and Figure 13 This is an explanation Figure 11 The diagram shows the ball bearings, the first track, and the second track.

[0039] Figure 14 This is a partial cross-sectional view showing the ball bearings and the magnetic yoke.

[0040] Figure 15 It is a diagram illustrating the structural relationship between the yoke, balls, magnet, and stroke.

[0041] Explanation of reference numerals in the attached figures

[0042] 1000: Actuator

[0043] 100: First carrier (AF carrier) 110: Groove track

[0044] 120: Second guide rail; 200: Second carrier (OIS carrier)

[0045] 210: Guide rail; 300: Housing

[0046] 310: Second groove track; 400: Circuit board.

[0047] 500: Magnetic yoke plate; 600: Housing

[0048] M1: First magnet (OIS magnet) M2: Second magnet (OIS magnet)

[0049] M3: AF magnet; H1: First Hall sensor (OIS Hall sensor)

[0050] H2: Second Hall sensor (OIS Hall sensor)

[0051] H3: Third Hall sensor (AF Hall sensor)

[0052] C1: First coil (OIS coil) C2: Second coil (OIS coil)

[0053] C3: AF coil; B1: First ball bearing

[0054] B2: AF ball bearing; B3: Second ball bearing. Detailed Implementation

[0055] 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.

[0056] 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.

[0057] The following is a reference. Figures 1 to 7 The following describes in detail the embodiments of the present invention that realize OIS and other functions. The specific details of the structural relationships of the OIS magnet, the stroke (AF stroke), the OIS coil, and the OIS Hall sensor will be described later.

[0058] Figure 1 This is a diagram illustrating the structure of a camera actuator (hereinafter referred to as "actuator") 1000 according to a preferred embodiment of the present invention. Figure 2 and Figure 3 This is an explanation Figure 1 The diagram shows the first ball bearing B1, the first track R1, and the second track R2, etc.

[0059] like Figure 1 As shown, the actuator 1000 of the present invention can be configured to include a first carrier (AF carrier) 100, a second carrier (OIS carrier) 200, a housing 300, a circuit board 400, a magnetic yoke plate 500, and a housing 600.

[0060] Figure 1 The Z-axis direction shown is the direction in which light is incident on the lens or lens assembly (not shown), i.e., the optical axis direction, which is equivalent to the direction in which the first carrier 100 moves forward and backward when driving AF. The X-axis and Y-axis, which are perpendicular to the optical axis, are equivalent to the direction in which the second carrier 200 moves when driving OIS.

[0061] In the following description of embodiments of the present invention, one of the two directions perpendicular to the optical axis will be referred to as the first direction (X-axis direction) and the other as the second direction (Y-axis direction). However, this is only an example based on a relative perspective. It is self-evident that either the X-axis direction or the Y-axis direction can be the first direction and the other direction can be the second direction.

[0062] 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 in some embodiments, it can be combined with a housing 600 used as a shield can.

[0063] The second carrier 200 is a movable body that moves along a first direction and / or a second direction with the first carrier 100 as a reference. When a lens or image sensor is mounted on the second carrier 200, the lens or image sensor moves as the second carrier 200 moves, thereby achieving OIS that eliminates external interference such as hand tremors.

[0064] From this perspective, the second carrier 200 is equivalent to a moving body that moves relative to the first carrier 100, while from the corresponding perspective, the first carrier 100 is equivalent to a relatively fixed body.

[0065] According to the embodiment, as shown in the figure, a first ball bearing B1 can be arranged between the first carrier 100 and the second carrier 200. In order to achieve effective guidance of linearity, preferably, the first ball bearing B1 is configured to be partially accommodated in one or more of the groove track 110 formed on the first carrier 100 and the guide rail 210 formed on the second carrier 200.

[0066] With the first ball B1 in place, the second carrier 200 maintains an appropriate distance from the first carrier 100 through the first ball B1, and can move more smoothly and linearly by means of the minimized friction generated by the movement and rolling of the first ball B1, thereby further improving noise reduction, driving force minimization and driving accuracy.

[0067] In the second carrier 200, which serves as a moving body, a first magnet M1 and a second magnet M2 are respectively provided opposite to the first coil C1 and the second coil C2. Figure 1 and Figure 2 As shown, the first magnet M1 and the second magnet M2 are disposed on the second carrier 200 and are disposed in mutually orthogonal directions.

[0068] The first magnet M1 and the second magnet M2 are equivalent to OIS magnets for OIS driving, and the first coil C1 and the second coil C2 are equivalent to coils for OIS driving.

[0069] If a power source of appropriate magnitude and direction is applied to the first coil C1, a magnetic force (electromagnetic force) is generated in the first magnet M1 located in the second carrier 200. Using the generated magnetic force as a driving force, the second carrier 200 moves along the first direction (X-axis direction) with the first carrier 100 as a reference.

[0070] According to the implementation, a detection sensor such as a first Hall sensor H1 may also be included. In this case, if the first Hall sensor H1 uses the Hall effect or the like to detect the position of the first magnet M1 of the second carrier 200 and transmits the corresponding signal to the driver D1 (see...), Figure 7 If the driver D1 then applies a power supply of a corresponding magnitude and direction to the first coil C1 in a cyclic manner, the driver D1 will then apply the power supply of the corresponding magnitude and direction in a cyclic manner.

[0071] The driver can be implemented not only as an independent electronic component or element, but also as a single electronic component (chip) integrated with the first Hall sensor H1 through a system-on-a-chip (SOC).

[0072] From the corresponding perspective, if a power supply of appropriate magnitude and direction is applied to the second coil C2, a magnetic force (electromagnetic force) is generated in the second magnet M2 of the second carrier 200. Using this generated magnetic force as a driving force, the second carrier 200 moves along the second direction (Y-axis direction) with the first carrier 100 as a reference. The contents of the second Hall sensor H2, etc., correspond to the contents of the aforementioned first Hall sensor H1, and are therefore omitted. The first Hall sensor H1 and the second Hall sensor H2 are equivalent to Hall sensors used for OIS driving.

[0073] The first coil C1, the first Hall sensor H1, the second coil C2, and the second Hall sensor H2 can be mounted on the housing 300 in a manner that allows them to be mounted on the circuit board 400. The same applies to the AF coil C3 and the third Hall sensor H3, which will be described later.

[0074] On the other hand, an AF magnet M3 is provided on one side of the first carrier 100, which is opposite to the AF coil C3 provided on the housing 300, and AF balls B2 are arranged between the second groove track 310 formed on the inner side of the housing 300 and the second track 120 formed on the outer side of the first carrier 100.

[0075] As described above, if a power supply of appropriate magnitude and direction is applied to the AF coil C3, an electromagnetic force will be generated between the AF coil C3 and the AF magnet M3. Under the action of this electromagnetic force, the first carrier 100 moves linearly along the optical axis (Z-axis direction) with the housing 300 as a reference. Therefore, regarding the driving of AF, the first carrier 100 becomes a relatively moving body, and from the corresponding perspective, the housing 300 becomes a relatively fixed body.

[0076] If the first carrier 100 moves along the optical axis, the second carrier 200 housed in the first carrier 100 also moves along the optical axis along with the first carrier 100, thereby causing the lens (not shown) mounted on the second carrier 200 to move linearly along the optical axis.

[0077] Thus, if the first carrier 100 moves along the optical axis, 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 and the lens is adjusted, thereby realizing the autofocus function or zoom function.

[0078] In the implementation of such AF function, feedback loop control using the third Hall sensor H3, etc., can also be applied as described above.

[0079] As described above, the first carrier 100 of the present invention is used as a relatively moving body in AF driving and as a relatively stationary body in OIS driving.

[0080] According to an embodiment, the housing 300 of the present invention may be provided with a magnetic yoke plate 500 that generates attraction with the AF magnet M3.

[0081] Under the attraction between the magnetic yoke plate 500 and the AF magnet M3, the first carrier 100, with the AF ball B2 as the medium, is pulled toward the housing 300, thus maintaining continuous contact between the AF ball B2 and the first carrier 100, as well as between the AF ball B2 and the housing 300.

[0082] Figure 2 and Figure 3 This is a diagram illustrating the detailed structure of the first carrier 100 and the second carrier 200 according to a preferred embodiment of the present invention. Figure 4 and Figure 5 This is a diagram showing the structure of the first ball bearing B1, the grooved track 110, and the guide rail 210. Figure 6 This is a diagram illustrating the physical structure of the second carrier 200 moving in all directions relative to the first carrier 100.

[0083] A guide rail 210 is formed in the second carrier 200 of the present invention, wherein the first ball B1 is arranged in the guide rail 210 in a manner that accommodates a portion of the first ball B1.

[0084] like Figure 2 As shown, the guide rail 210 has a groove extending along its length. Figure 2 The diagram shows a guide rail 210 with a track structure extending along the X-axis direction (first direction) as an example.

[0085] Therefore, the first ball B1 housed in the guide rail 210 can move freely in a specific direction, but its movement in a direction orthogonal to the direction in which it can move freely is restricted.

[0086] From the perspective of the second carrier 200, the second carrier 200 can move freely in the first direction (X-axis direction) using the first ball B1 as a medium, but its movement in the second direction (Y-axis direction) is restricted.

[0087] In other words, when the second carrier 200 moves along the first direction, the second carrier 200 can move independently of the first ball B1 while maintaining contact with the first ball B1. However, when the second carrier 200 moves along the second direction, the free movement between it and the first ball B1 is restricted, so the second carrier 200 moves together with the first ball B1.

[0088] To more clearly realize this motion characteristic, preferably, the vertical cross-section of the groove shape of the guide rail 210 is V-shaped.

[0089] With the guide rail configured in this V-shape, contact with the first ball B1 is achieved on the inclined surface, thus more effectively restricting movement in the second direction (Y-axis direction), and improving the linearity (straightness) of free movement along the first direction.

[0090] On the other hand, such as Figure 3 As shown, the grooved track 110 formed on the first carrier 100 also has a shape in which the groove extends along the length direction, but has a shape in which it extends in a direction orthogonal to the extension direction of the guide rail 210. Figure 3 The diagram shows a grooved track 110 with a guide rail structure extending along the Y-axis direction (second direction) as an example.

[0091] With the grooved track 110 as a reference, unlike the guide rail 210, the first ball B1 can move freely along the Y-axis direction (second direction), but its movement along the first direction (X-axis direction) is restricted.

[0092] Therefore, with the first ball B1 located between the guide rail 210 and the grooved track 110 as a reference, the guide rail 210 and the grooved track 110 are in a shape where the extension directions of each track in the upper and lower parts are perpendicular to each other and cross each other.

[0093] That is, such as Figure 4 As shown, with the YZ plane as the reference, the guide rail 210 with a V-shaped cross section (specifically an inverted V) contacts the first ball B1 at the upper part, and a grooved track 110 is provided at the lower part of the first ball B1. The grooved track 110 has space extending along the length direction.

[0094] In addition, such as Figure 5 As shown, with the XZ plane as a reference, the grooved track 110 with a V-shaped cross section contacts the first ball B1 at the lower part, and a guide rail 210 is provided at the upper part of the first ball B1. The guide rail 210 has space extending along the length direction.

[0095] In this structure, if a driving force in the first direction (X-axis direction) is generated by the magnetic force between the first magnet M1 and the first coil C1, the first ball B1 is restricted from moving by the grooved track 110 located below it. In this state, the second carrier 200 moves along the first direction by being guided by the guide rail 210 extending along the first direction and the first ball B1. As described above, in this case, the first ball B1 does not move with the first carrier 100.

[0096] From the corresponding perspective, if a driving force in the second direction (Y-axis direction) is generated between the second magnet M2 and the second coil C2, the second carrier 200 and the first ball B1 whose movement is restricted by the guide rail 210 move together along the grooved track 110 extending in the second direction.

[0097] Thus, when the guide rails 210 and the grooved track 110 are orthogonal to each other and intersect simultaneously, not only can independent movement in the first and second directions that are perpendicular to each other be realized, but also the linearity or straightness of movement in each direction can be effectively realized.

[0098] In the embodiment illustrated in the accompanying drawings, all guide rails 210 are shown as tracks extending in a first direction (X-axis direction), and all grooved tracks 110 are shown as tracks extending in a second direction (Y-axis direction). However, this is only one embodiment. It is self-evident that as long as the extending shapes of the guide rails 210 and the grooved tracks 110 can intersect each other orthogonally, a portion of the guide rails 210 can extend in the first direction and another portion in the second direction.

[0099] In addition, the illustrated embodiment shows four pairs of opposing guide rails 210 and grooved tracks 110, but this is only one embodiment. Regardless of their position, as long as there are two or more pairs of opposing guide rails 210 and grooved tracks 110, independent movement in each direction can be achieved.

[0100] Therefore, m (m is a natural number greater than 2) groove tracks 110 can be set on the first carrier 100, and n (n is a natural number greater than 2) guide rails 210 can be set on the second carrier 200. Moreover, two or more of the above m groove tracks 110 are respectively opposite to (orthogonal and intersecting) two or more of the above n guide rails.

[0101] n and m can preferably be the same number, but even if the numbers are different, as described above, as long as there are two or more pairs of opposite (orthogonal and intersecting) groove tracks 110 and guide rails 210, the technical concept of the present invention can be realized.

[0102] Furthermore, when the quantities are different, the side of the groove track 110 and guide rail 210 opposite to the redundant structure can be formed into a planar shape to allow the first ball B1 to move freely.

[0103] According to the implementation method, the side opposite to the above-mentioned redundant structure can allow the first ball B1 to move freely in a certain area, but it can also be formed into a receiving groove shape to prevent it from detaching from the outside of the corresponding area.

[0104] More preferably, the opposing (orthogonal and intersecting) grooved tracks 110 and guide rails 210 are both formed by V-shaped tracks. With this configuration, not only can the first ball B1 be effectively prevented from disengaging or moving in an unintended direction, but it can also be guided to move linearly and accurately along a specific intended direction.

[0105] In order to effectively maintain contact between the second carrier 200 and the first ball B1, and between the first ball B1 and the first carrier 100, and to enable the second carrier 200 to return to the reference position when the OIS drive in each direction stops, preferably, a magnetic body made of magnetic material is provided on the first carrier 100, which generates attraction with the first magnet M1 and the second magnet M2 provided on the second carrier 200.

[0106] Figure 7 This is a diagram illustrating another embodiment of the OIS carrier (second carrier) 200.

[0107] like Figure 7 As illustrated, the OIS carrier 200 of the present invention can also be implemented in the form of a lens carrier 200A equipped with a lens and an intermediate guide 200B.

[0108] In this embodiment, the first ball B1 can be arranged between the lens carrier 200A and the intermediate guide 200B, and the second ball B3 can be arranged between the intermediate guide 200B and the AF carrier (first carrier) 100.

[0109] With this structure, if a driving force is generated between the first magnet M1, which is the OIS magnet, and the first coil C1, which is the OIS coil, the lens carrier 200A moves along the first direction (X-axis direction) guided by the second ball B3, with the intermediate guide 200B and the AF carrier 100 as relatively fixed bodies.

[0110] Furthermore, if a driving force is generated between the second magnet M2, which serves as the OIS magnet, and the second coil C2, which serves as the OIS coil, the lens carrier 200A moves along the second direction (Y-axis direction) with the intermediate guide 200B as a relatively fixed body and the first ball B1 as a physical guide.

[0111] Figure 7 Other structures shown and Figures 1 to 6 The descriptions have the same or corresponding structures, so detailed explanations are omitted.

[0112] Figure 8 This is a diagram showing the internal structure of an actuator 1000 according to an embodiment of the present invention. Figure 9 This is a detailed explanation. Figure 8 The diagram in part A, Figure 10This is a diagram illustrating the relative positions of the second magnet M2, which is one of the OIS magnets M1 and M2; the second coil C2, which is one of the OIS coils C1 and C2; and the second Hall sensor H2, which is one of the OIS Hall sensors.

[0113] As described above, the OIS carrier 200 of the present invention is a moving body that moves along a direction perpendicular to the optical axis (Z-axis direction) (X-axis direction and / or Y-axis direction), and the AF carrier 100 of the present invention is equivalent to a relatively fixed body that supports the movement of the OIS carrier 200.

[0114] When the AF is driven, the AF carrier 100 of the present invention moves forward and backward along the optical axis direction (Z-axis direction) with the housing 300 as the relatively fixed body. Since the OIS carrier 200 is supported by the AF carrier 100, when the AF carrier 100 moves along the optical axis direction, the OIS carrier 200 also moves along the optical axis direction with the AF carrier 100.

[0115] The following observation examines the positional relationships between the OIS magnets M1 and M2 and the OIS coils C1 and C2, as well as the positional relationships between the OIS magnets M1 and M2 and the OIS Hall sensors H1 and H2, when the OIS carrier moves up and down with the optical axis as a reference, driven by AF.

[0116] OIS magnets M1 and M2 are disposed on OIS carrier 200. Therefore, when OIS carrier 200 moves along the optical axis direction together with AF carrier 100 by AF drive, OIS magnets M1 and M2 also move along the optical axis direction.

[0117] When AF is driven, the positions of OIS magnets M1 and M2 relative to the optical axis will change, but the OIS coils C1 and C2 that provide driving force to OIS magnets M1 and M2, as well as the OIS Hall sensors H1 and H2 that detect the magnetic force of OIS magnets M1 and M2, are located in the housing 300, so their positions will not change due to AF driving.

[0118] Therefore, when the AF is driven, the positional relationship between the OIS magnets M1 and M2 and the OIS coils C1 and C2, as well as the positional relationship between the OIS magnets M1 and M2 and the OIS Hall sensors H1 and H2, will change dynamically depending on whether the AF is driven or not, and the amount of movement caused by the AF.

[0119] Typically, position detection for OIS is designed based on the positioning relationship between OIS magnets M1 and M2 and OIS Hall sensors H1 and H2, while the driving force for OIS is designed based on the positioning relationship between OIS magnets M1 and M2 and OIS coils C1 and C2.

[0120] However, if the positional relationship between these (OIS magnet and OIS coil, OIS magnet and OIS Hall sensor) changes due to AF drive, it will be difficult to accurately achieve not only position detection for OIS, but also the provision of driving force for OIS.

[0121] In particular, when the movement distance (stroke) of the AF carrier 100 caused by AF drive increases due to the high specifications of the lens, the range of positional deviation between them becomes larger, and the accuracy of position detection and OIS drive force provided by OIS may be further reduced.

[0122] To address this issue, one could improve the algorithm used for drive control, but as mentioned above, this would increase computation time and potentially negatively impact response characteristics.

[0123] To address this problem from a structural engineering perspective, preferably, the height (based on the optical axis direction) h1 of the OIS magnets M1 and M2 according to the present invention is configured as follows (see...). Figure 9 The distance traveled by the AF carrier 100 caused by the AF drive, i.e., the stroke (S1+S2), is more than twice that of the stroke.

[0124] Thus, when the height of OIS magnets M1 and M2 (based on the Z-axis) is more than twice the stroke, even if the position (optical axis direction) of OIS magnets M1 and M2 changes due to AF drive, they can maintain their relative positional relationship with OIS coils C1 and C2, thereby improving the efficiency of providing driving force.

[0125] The upper limit of the height of OIS magnets M1 and M2 can be determined based on the height of the actuator 1000 itself or the position and structure of the stop components and other internal components of the actuator 1000.

[0126] The heights (optical axis direction / Z-axis direction) of OIS coils C1 and C2 can be designed to correspond to the heights of OIS magnets M1 and M2, which is self-evident.

[0127] Figure 9 The AF carrier 100 and related structures are shown at the midpoint of the stroke. As mentioned above, the AF carrier 100 being at the midpoint of the stroke means that the OIS magnets M1 and M2 are also located at the corresponding positions.

[0128] by Figure 9 When taken as a reference, the distance that the AF carrier 100 moves along the optical axis due to AF drive, i.e., the stroke, is the sum of S1 and S2.

[0129] If the AF carrier 100 rises upward along the optical axis, the size of S1 decreases and the size of S2 increases; conversely, if the AF carrier 100 descends downward with the optical axis as the reference, the opposite occurs. Even if the position of the AF carrier 100 along the optical axis changes, the stroke remains constant.

[0130] OIS (Optical Image Stabilizer) can be described as a function that moves the lens in the opposite direction to prevent image quality degradation caused by camera shake or other phenomena. The closer the shooting distance, or even in macro shooting environments, the more noticeable the effects of camera shake become due to the optical relationship between the subject, lens, and image sensor.

[0131] Therefore, preferably, the higher the resolution or accuracy of the OIS Hall sensors H1 and H2 is designed, the more accurately the OIS driving force is provided in scenarios equivalent to close-up shooting.

[0132] Close-up shooting refers to the close distance between the lens and the subject. This means that the AF carrier 100 rises relative to the optical axis due to the drive of AF, etc., that is, the OIS carrier 200 with OIS magnets M1 and M2 set rises relative to the optical axis.

[0133] The better the positional match between OIS magnets M1 and M2 and OIS Hall sensors H1 and H2, the higher the resolution and accuracy; the better the positional relationship between OIS magnets M1 and M2 and OIS coils C1 and C2, the better the driving performance and accuracy.

[0134] Therefore, as Figure 9 and Figure 10 As illustrated in the example, preferably, when the AF carrier 100 is located at the middle position of the stroke, the center position CP1 of the OIS magnets M1 and M2 according to the present invention is the same as or lower than the center position CP2 of the OIS coils C1 and C2 and the center position CP3 of the OIS Hall sensors H1 and H2.

[0135] The center position refers to the middle position based on the height (optical axis direction) of the corresponding structure.

[0136] Thus, if the AF carrier 100 is positioned at the middle of its travel as a reference, and the center position CP1 of the OIS magnets M1 and M2 is lower than the center position CP3 (Δh2) of the OIS Hall sensors H1 and H2, and the center position CP1 of the OIS magnets M1 and M2 is lower than the center position CP2 (Δh1) of the OIS coils C1 and C2, then when the AF carrier 100 rises in the corresponding close-range shooting environment (based on the optical axis direction), the matching rate between the center positions of the OIS magnets M1 and M2 and the center positions of the OIS Hall sensors H1 and H2, as well as the matching rate between the center positions of the OIS magnets M1 and M2 and the center positions of the OIS coils C1 and C2, will be improved.

[0137] With this configuration, in scenarios where higher accuracy of position detection and driving is required, such as close-range shooting scenarios where the AF carrier 100 and OIS carrier 200 rise due to AF driving, the position matching rate between OIS magnets M1 and M2 and OIS Hall sensors H1 and H2, as well as between OIS magnets M1 and M2 and OIS coils C1 and C2, is improved, thus enhancing the accuracy of position detection and driving.

[0138] Preferably, the height deviation (Δh1) between the center position CP1 of the OIS magnets M1 and M2 and the center position CP2 of the OIS coils C1 and C2, and the height deviation (Δh2) between the center position CP1 of the OIS magnets M1 and M2 and the center position CP3 of the OIS Hall sensors H1 and H2, is less than 30% of the stroke, with the AF carrier 100 located at the middle position of the stroke.

[0139] With the AF carrier 100 positioned at the middle of its stroke as a reference, and the center position CP1 of the OIS magnets M1 and M2 being too low, it will not only increase the structural design difficulty of the actuator 1000, but also make it difficult to maintain the normal operation of the OIS (position detection and driving force provision, etc.) when the OIS magnets M1 and M2 move in the negative direction (-Z axis direction) with the middle position of their stroke as a reference due to the AF. It may even lead to problems such as a decrease in driving force due to the reduction in the size of the OIS magnets M1 and M2.

[0140] Preferably, such as Figure 10 As illustrated in the example, with the AF carrier 100 located at the middle position of the stroke as a reference, the center position CP3 of the OIS Hall sensors H1 and H2 of the present invention can be configured to be higher than the center position of the OIS coils C1 and C2.

[0141] Hall sensors utilize the Hall effect to detect the magnitude and direction of the magnetic field of a magnet within the detection area. Based on experiments and simulations under various environmental conditions, the linearity between the magnet's position (based on the driving direction of the OIS, such as the X-axis or Y-axis) and the output value of the Hall sensor improves towards optimization when the center position CP3 of the OIS Hall sensors H1 and H2 is slightly higher than the center position CP1 of the OIS magnets M1 and M2 (optical axis direction).

[0142] Therefore, when the center position of the OIS Hall sensors H1 and H2 is higher than the center position of the OIS coils C1 and C2, higher OIS performance can be achieved in close-range shooting scenarios.

[0143] The following is for reference Figures 11 to 15 The following details the actuator 100 according to the second embodiment of the present invention.

[0144] The terms and / or reference numerals used in the actuator and its included structures described below in the second embodiment may differ from those used in the foregoing embodiments.

[0145] This is for the purpose of distinguishing embodiments and effectively explaining the corresponding embodiments. Therefore, as long as those skilled in the art can realize the corresponding technical ideas, the structure of the embodiments described below should be interpreted as the same as or equivalent to the aforementioned structure.

[0146] For example, the carrier 110 described in the second embodiment below corresponds to the structure of the AF carrier 100 (first carrier) described in the previous embodiment, and the shell 120, magnetic yoke plate 150, circuit board 140 and housing 160 of the second embodiment correspond to the structures of the shell 300, magnetic yoke plate 500, circuit board 400 and housing 600 of the previous embodiment, respectively.

[0147] Figure 11 This is a diagram illustrating the structure of a camera actuator (hereinafter referred to as "actuator") 100 according to a preferred second embodiment of the present invention. Figure 12 and Figure 13 This is an explanation Figure 11 The diagram shows the ball bearing B, the first track R1, and the second track R2, etc.

[0148] Hereinafter, the general structure of the actuator 100 of the present invention will be described first, and the specific contents of the present invention, such as the structural relationship between the ball B, the magnetic yoke 150, the magnet M, and the stroke H3, will be described later.

[0149] like Figure 11As shown, the actuator 100 according to the second embodiment of the present invention may be composed of a carrier 110, a housing 120, a circuit board 140, a magnet M and a coil C. According to the embodiment, it may include a housing 160 that serves as a shield.

[0150] The actuator 100 according to the present invention is equivalent to a device that uses the electromagnetic force (magnetic force) between the coil C and the magnet M as a driving force to move the carrier 110 in a linear forward or backward direction to achieve AF or zoom function.

[0151] The accompanying drawings illustrate an embodiment of AF implementation alone, but it goes without saying that the actuator 100 of the present invention can be applied not only to actuators that integrate AF and OIS functions as in the foregoing embodiments, but also to actuators that apply reflectors, etc.

[0152] The carrier 110 of the present invention can be located in the internal space provided by the housing 120, which is equivalent to a moving body that moves along the optical axis with the housing 120 as a reference. From the corresponding perspective, the housing 120, which supports the linear movement of the carrier 110, is equivalent to a relatively fixed body.

[0153] According to the embodiment, one or more lenses or lens assemblies (hereinafter referred to as "lenses") may be mounted on the carrier 110. When such a lens is mounted on the carrier 110, the lens moves linearly by moving the carrier 110. By moving the lens, the relative distance between the lens and the image sensor is adjusted, thereby realizing the AF or zoom function.

[0154] The drive unit that makes the carrier 120 move linearly along the optical axis is a structure that moves the carrier 110 in a specific direction by means of external control signals or detected signal systems. It can be realized by various means such as shape memory alloy (SMA), piezoelectric element, microelectromechanical system (MEMS).

[0155] However, considering the efficiency of device miniaturization, power consumption, noise suppression, space utilization, linear movement characteristics, and precise control, the drive unit is preferably implemented by using a structure that utilizes the electromagnetic force (magnetic force) generated between a magnet and a coil, as illustrated in the figure.

[0156] In this regard, the coil can also be set on a moving body, and the magnet can also be set on a fixed body. However, in order to improve the efficiency of electrical connection, structural design, etc., as shown in the figure, preferably, the magnet M is set on the carrier 110, which is a moving body, and the coil C is set on the shell 120, which is a relatively fixed body.

[0157] According to the embodiment, it may include a Hall sensor for detecting the position of a magnet M1 or a sensing magnet, and a driver D for controlling the magnitude and direction of the current supplied to the coil C using the signal output by the Hall sensor. Since the Hall sensor is usually implemented as a single electronic component (chip) integrated with the driver D, it is not shown separately in the figures.

[0158] The coil C and driver D can be mounted on the circuit board 140, and in order to interface with external modules, power supply units, external devices, etc., the circuit board 140 is preferably configured to expose a portion of it to the outside.

[0159] A plurality of balls B are arranged between the carrier 110 and the housing 120. Specifically, the plurality of balls B may be a first ball group B1 arranged on a first track R1 and / or a second ball group B2 arranged on a second track R2. The first track R1 is formed on one or more of the carrier 110 and the housing 120, and the second track R2 is formed on one or more of the carrier 110 and the housing 120 and is formed parallel to the first track R1.

[0160] To effectively guide the linear movement of the carrier 110, preferably, the balls belonging to the first ball group B1 are partially housed within the first track R1. The same applies to the balls corresponding to the second ball group B2. Within the range where there is no need to distinguish between the balls belonging to the first ball group and the first balls of the first ball group, the same reference numeral B1 is used to indicate them.

[0161] The attached diagram shows that both the first ball group B1 and the second ball group B2 are composed of multiple balls arranged along the optical axis, but one of the ball groups can be composed of a single ball.

[0162] The accompanying drawings show an embodiment where both the carrier 110 and the housing 120 have the first track R1, but according to the implementation, the first track may be present only on one of them. In this case, the structure without the first track may have a groove or receiving groove, which accommodates one or more balls (first balls) belonging to the first ball group B1 and prevents the first ball B1 from detaching outward. The same applies to the second track R2.

[0163] With the balls B1 and B2 positioned between the carrier 110 and the housing 120, the moving body (carrier) can move more flexibly and linearly by minimizing the friction generated by the rolling, moving, rotating, and point-contacting of the balls with the relative object. This can reduce noise, decrease driving force, and improve driving accuracy.

[0164] Regarding the tracks R1 and R2 for arranging the ball bearings B1 and B2, the cross-section of one of the tracks (a horizontal cross-section based on the optical axis direction) can be configured as a "V" shape, and the cross-section of the other track can be configured as a "U" shape.

[0165] Thus, when the cross-sections of the first track R1 and the second track R2 are configured to have different shape characteristics, the contact parts and rotational characteristics with the balls B1 and B2 can be configured differently, thereby improving the linearity of movement and the driving efficiency of the carrier 110 moving along the optical axis.

[0166] When both the carrier 110 and the housing 120 have a second track R2 with a "V" shaped cross-section, the second track R2 is arranged with its open portions facing each other, and one or more balls belonging to the second ball group B2 are arranged between them. Therefore, the second ball B2 is in contact with both the second track R2 of the carrier 110 and the second track R2 of the housing 120 while being partially accommodated in the second track R2.

[0167] Through this physical structure, the carrier 110 moves accurately and linearly by means of the physical support of the second ball bearing assembly B2 and the guidance of the second track R2.

[0168] The "V-shaped" cross-section refers not only to the V-shape of the letter itself, but also to the shape in which the inner surfaces of the second ball B2 and the second track R2 are in contact at two points.

[0169] When the cross-section of the first track R1 provided on the housing 120 is U-shaped, in order to achieve linear movement of the carrier 110, preferably, the cross-section of the first track R1 provided on the carrier 110 opposite to the track R1 is V-shaped.

[0170] The "U-shaped" cross-section refers not only to the shape of the letter U itself, but also to the fact that a certain gap can exist between the inner surface of the ball and the track, including shapes such as trapezoids.

[0171] The accompanying drawings, as an example, show an embodiment in which the first track R1 and the second track R2 provided on the carrier 110 both have V-shaped cross sections, and one of the first track R1 and the second track R2 provided on the housing 120 has a V-shaped cross section and the other track has a U-shaped cross section.

[0172] The housing 120 of the present invention includes a magnetic yoke plate 150 made of magnetic material, which generates an attractive force with the magnet M disposed on the carrier 110.

[0173] If an attractive force or suction force is generated between the magnet M and the yoke plate 150, then with the balls B1 and B2 disposed between the carrier 110 and the housing 120, the carrier 110 will be attached to the housing 120 in the direction of the X-axis (based on the attached figure), thus maintaining physical contact between the balls B1 and B2 and the carrier 110, as well as between the balls B1 and B2 and the housing 120.

[0174] Figure 14 This is a partial cross-sectional view showing the ball bearing B and the magnetic yoke plate 150. Figure 15 This is a diagram illustrating the structural relationship between the magnetic yoke plate 150, ball bearing B, magnet M, and stroke H3.

[0175] As described above, the magnetic yoke plate 150 of the present invention is a structure provided on the shell 120, which is a relatively fixed body, and generates attraction with the magnet M provided on the carrier 110, which is a moving body.

[0176] Magnet M is a permanent magnet, and yoke plate 150 is made of magnetic material, so the attraction between them will continue to be generated regardless of whether carrier 110 moves.

[0177] Since ball B is arranged between carrier 110 and housing 120, even if magnet M on carrier 110 moves forward and backward along the optical axis due to AF drive, the contact force between housing 120 and ball B and between ball B and carrier 110 must be maintained in order to continuously achieve linear movement of carrier 110 with AF drive in a gapless or tilted manner.

[0178] Therefore, preferably, the height H1 of the magnetic yoke plate 150 is designed to be greater than the height H2 of the magnet M, and more preferably, it is configured to be greater than the sum of the height H2 of the magnet M and the range or length region of the carrier 110 moving along the optical axis, i.e., the stroke H3 (H2+H3).

[0179] The multiple balls B arranged between the housing 120 and the carrier 110 not only provide physical support for the carrier 110, but also directly guide the physical movement of the carrier 110. As described above, the balls B can move freely along the optical axis, but do not have the same movement characteristics as the carrier 110 in terms of movement direction and distance.

[0180] Therefore, it is necessary to maintain the physical support or guidance of the ball B on the carrier 110, and the physical contact point (position of point contact) between the ball B and the carrier 110 must not exceed the attraction area based on the magnet M and the magnetic yoke plate 150, in order to avoid problems such as tilting of the carrier 110.

[0181] Therefore, preferably, the sum of the height (stack height) H4 of the plurality of balls B as a whole and the stroke H3 (H4+H3) (hereinafter referred to as "first distance") is less than the sum of the radius of one of the plurality of balls B (hereinafter referred to as "comparison ball") and the height of the magnetic yoke plate 150 (R+H1).

[0182] If all the balls B are made of the same diameter, then it doesn't matter if the ball being compared is any one of the balls.

[0183] If the end of the carrier 110 (based on the optical axis) extends beyond the center of the outermost ball B (based on the optical axis) among the plurality of balls B, the balance support of the carrier 110 may be disrupted. Therefore, if the sizes of the plurality of balls B are not exactly the same, preferably, the aforementioned comparative ball is the outermost ball BS among the plurality of balls B.

[0184] The diameters of multiple balls B cannot be exactly the same, and the movement and stopping of the carrier 110 during AF driving are random. Therefore, when the carrier 110 moves along the optical axis, the balls B that are actually in contact with the carrier 110 may change at any time.

[0185] Therefore, when the outermost ball BS (hereinafter referred to as "main ball") among the multiple balls B arranged along the optical axis has a larger diameter than the diameters of the other balls B, the carrier 110 can be guided in such a way that it is always in contact with the main ball BS. Furthermore, since the main ball BS with a relatively large diameter is arranged on the outermost side among the multiple balls, the possibility of the carrier 110 tilting can be relatively reduced.

[0186] The accompanying drawings show a first ball group B1 and a second ball group B2 consisting of the same number of balls. However, according to an embodiment, the first ball group B1 and the second ball group B2 may consist of different numbers of balls. As mentioned above, one of the ball groups may also consist of a single ball.

[0187] Thus, when multiple ball sets are arranged side by side between the housing 120 and the carrier 110, preferably, the "overall height H4 of the multiple ball sets B", which is one of the constituent elements of the first distance (H4+H3) mentioned above, is determined to be the overall height of the ball set with the relatively larger overall height among the multiple ball sets (hereinafter referred to as the "support ball set").

[0188] In this case, preferably, the first distance (H4+H3) is configured such that the sum of the height H4 and the stroke H3 of the support ball group is less than the sum of the radius R of the outermost ball in the support ball group and the height H1 of the magnetic yoke plate 150 (R+H1).

[0189] If a power source of appropriate magnitude and direction is applied to coil C under the control of driver D, a magnetic force (electromagnetic force) will be generated between coil C and magnet M. As shown in the figure, preferably, coil C, which generates the driving force, is designed to cover the height region of the movement range (stroke) of magnet M mounted on carrier 110.

[0190] The magnet M is a structure with weight and is set on the carrier 110, which is a moving body. Therefore, it may be used as a load caused by driving. If we do not consider this for the time being, the object directly acted by the driving force generated by the coil C is the magnet M. Therefore, the larger the size of the magnet M (the height based on the optical axis direction), the greater the driving force may be.

[0191] However, since the magnet M is the object on which the driving force is directly applied, if the driving force is also applied to the area beyond the area physically supported by the ball B, it may be relatively easy for the carrier 110 to have poor posture.

[0192] Therefore, preferably, the height of the magnet M (based on the optical axis) is less than the sum of the height H4 of the plurality of balls B as a whole and the radius R of the outermost ball BS among the plurality of balls (H4+R). In this case, the height of the plurality of balls as a whole can also be the height of the supporting ball assembly, which is self-evident.

[0193] 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.

[0194] 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 not be used to indicate a specific order, priority, etc.

[0195] 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 OIS carrier moves in a direction perpendicular to the optical axis. The AF carrier supports the OIS carrier and moves together with the OIS carrier along the optical axis. The housing supports the AF carrier; An OIS magnet is disposed on the OIS carrier; as well as An OIS coil is disposed in the housing in a manner opposite to the OIS magnet. The height of the OIS magnet is more than twice the stroke, where the stroke is the distance the AF carrier moves due to AF drive.

2. The camera actuator according to claim 1, characterized in that, When the AF carrier is located in the middle of the stroke, the center position of the OIS magnet is the same as or lower than the center position of the OIS coil.

3. The camera actuator according to claim 2, characterized in that, When the AF carrier is located in the middle of the stroke, the height deviation between the center position of the OIS magnet and the center position of the OIS coil is less than 30% of the stroke.

4. The camera actuator according to claim 1, characterized in that, It also includes an OIS Hall sensor that detects the position of the OIS magnet and is disposed in the housing. When the AF carrier is located in the middle of the stroke, the center position of the OIS magnet is the same as or lower than the center position of the OIS Hall sensor.

5. The camera actuator according to claim 4, characterized in that, When the AF carrier is located in the middle of the stroke, the height deviation between the center position of the OIS magnet and the center position of the OIS Hall sensor is less than 30% of the stroke.

6. The camera actuator according to claim 1, characterized in that, Also includes: An AF magnet is disposed on the AF carrier in a manner opposite to an AF coil disposed on the housing; A magnetic yoke plate, disposed in the housing, and attracting the AF magnet; and Ball bearings are arranged between the housing and the AF carrier. The height of the magnetic yoke plate is greater than the sum of the height of the AF magnet and the stroke.

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