Actuator for a camera and camera module comprising the actuator

Abstract

An actuator for a camera and a camera module including the same. The actuator for a camera according to an embodiment of the disclosure includes a first carrier having a guide rail formed to extend in an optical axis direction and disposed at an outer side of the first carrier, the first carrier configured to move in the optical axis direction, a second carrier configured to move in a direction perpendicular to the optical axis and accommodated at an inner side of the first carrier, a housing configured to accommodate the first carrier, and a ball disposed between the guide rail and the housing, and a first interval as a gap between a first section of the inner side of the first carrier where the guide rail is disposed and an outer side of the second carrier is greater than a second interval as a gap between a second section of the inner side of the first carrier where the guide rail is not disposed and the outer side of the second carrier.

Description

Technical Field

[0001] This disclosure relates to an actuator for a camera and a camera module including the actuator, and more specifically, to an actuator for a camera with improved actuation performance by enhancing the physical face structure between carriers and a camera module including the actuator. Background Technology

[0002] With the development of hardware technology for image processing and the increasing demand for image capture, features such as autofocus (AF) and optical image stabilization (OIS) have been applied to camera modules installed in portable terminals such as cellular phones and smartphones, as well as stand-alone camera devices.

[0003] Autofocus (AF) function (or autofocus function) refers to the function of achieving the appropriate focal length for a subject by linearly moving a carrier with a lens along the optical axis to generate a clear image at an image sensor (CMOS, CCD, etc.) located behind the lens.

[0004] In addition, the optical image stabilization (OIS) function refers to the function of improving image sharpness by adaptively moving the carrier with the lens in the direction of the jitter when the compensating lens jitters.

[0005] Recently, devices or actuators integrating AF and OIS functions have been used. In this case, the configuration for moving the OIS carrier on which the lens is mounted within the AF carrier in the X-axis direction and / or Y-axis direction perpendicular to the optical axis is implemented as a whole with the configuration for moving the AF carrier.

[0006] Furthermore, in devices that implement AF function or devices that implement both AF and OIS functions, a structure in which a sphere arranged in the same direction as the optical axis is inserted between the AF carrier (mover) and the housing (stator) is used to improve the behavior characteristics of the AF carrier moving in the direction of the optical axis.

[0007] This structure allows for maintaining a proper separation distance between the mover and stator continuously, and by minimizing the friction generated by the movement and rolling of the sphere itself and by point contact with the sphere, the AF carrier can move more flexibly and precisely in the optical axis direction.

[0008] These spheres are made of materials with high strength or hardness (e.g., metal or ceramic), and the moving parts that come into contact with the spheres are mainly made of plastic materials to increase the ease of molding.

[0009] If the sphere and the object in contact with the sphere are made of dissimilar materials, the guiding components in contact with the sphere may be easily damaged or worn when an external impact or vibration occurs due to the difference in hardness between the dissimilar materials.

[0010] In addition, because the sphere is made into a spherical shape, the part in contact with the sphere becomes the point of greatest force or pressure, so external impacts may further aggravate the damage or wear of local components.

[0011] If the components of the guide ball are damaged or worn, or if foreign matter such as particles separated from the plastic material is generated, tilting failure, linear interruption, or position control failure of the AF carrier may occur, which may degrade the overall driving performance of the AF carrier.

[0012] Furthermore, in the case of a device or actuator that houses the OIS carrier inside the AF carrier, the OIS carrier must move in a direction perpendicular to the optical axis, thereby creating a free space between the outer side of the OIS carrier and the inner side of the AF carrier.

[0013] Therefore, in the event of a drop, external impact, or vibration, the OIS carrier located inside the AF carrier will impact the inside of the AF carrier, and the force generated by the impact will be transmitted to the outside of the AF carrier, where the ball is guided as is. Due to this phenomenon, the components guiding the ball may be damaged or worn.

[0014] However, in the prior art, only a few methods have been proposed to solve the problems caused by heterogeneous materials, and the aforementioned problems that may be damaged due to collisions between the outer side of the OIS carrier and the inner side of the AF carrier have not been recognized, so there is no way to solve the problem at all. Summary of the Invention

[0015] Technical issues

[0016] This disclosure is designed to address the problems of the prior art, and therefore aims to provide an actuator for a camera, etc., that can further improve the driving accuracy of the linear movement of the AF carrier by more effectively suppressing wear or damage to the track structure of the guide ball.

[0017] These and other objects and advantages of this disclosure will become apparent from the following detailed description and from the exemplary embodiments thereof. Furthermore, it will be readily understood that the objects and advantages of this disclosure can be achieved by the means shown in the appended claims and combinations thereof.

[0018] Technical solution

[0019] An actuator for a camera according to an embodiment of the present disclosure includes: a first carrier having a guide rail formed to extend in the optical axis direction and disposed on the outer side of the first carrier, the first carrier being configured to move in the optical axis direction; a second carrier being configured to move in a direction perpendicular to the optical axis and housed inside the first carrier; a housing being configured to house the first carrier; and a sphere being disposed between the guide rail and the housing, wherein a first interval, which is the interval between a first segment and the outer side of the second carrier, is greater than a second interval, which is the interval between a second segment and the outer side of the second carrier, the first segment being the inner side of the first carrier where the guide rail is disposed, and the second segment being the portion of the inner side of the first carrier where the first segment is disposed without the guide rail.

[0020] More preferably, the actuator for a camera according to the present disclosure may further include an avoidance space formed between the first section and the second section.

[0021] In this case, the avoidance space of this disclosure may include a corresponding surface disposed toward the first section and having a shape corresponding to the surface of the guide rail.

[0022] Furthermore, the first and second sections of this disclosure may have a shape that protrudes outward toward the second carrier, and the protrusion dimension of the first section may be smaller than that of the second section.

[0023] According to one embodiment, the edge portion of the second carrier adjacent to the first segment may have an inclined shape or an arc shape.

[0024] Beneficial effects

[0025] According to a preferred embodiment of this disclosure, by effectively suppressing or preventing the impact force applied to the inside of the AF carrier from being transmitted to the track structure of the guide ball, damage, breakage, dents, etc., at the track structure of the guide ball can be more effectively prevented.

[0026] According to this disclosure, linear mobility can be precisely maintained and tilting of the AF carrier can be effectively suppressed, thereby improving the overall driving performance of the actuator.

[0027] Furthermore, according to another embodiment of this disclosure, since the structure for collision suppression, etc., can be implemented by applying a simple structure to the outside of the OIS carrier and / or the inside of the AF carrier, the actuator assembly and manufacturing process can be performed more efficiently, and the service life of the actuator can be further increased by enhancing durability. Attached Figure Description

[0028] The accompanying drawings illustrate preferred embodiments of the present disclosure and, together with the foregoing disclosure, serve to provide a further understanding of the technical features of the present disclosure; therefore, the present disclosure is not to be construed as limited to the drawings.

[0029] Figure 1 This is a diagram illustrating the overall configuration of an actuator for a camera according to a preferred embodiment of the present disclosure.

[0030] Figure 2 and Figure 3 This is a diagram illustrating the specific construction of the first carrier and the second carrier according to a preferred embodiment of the present disclosure, and

[0031] Figures 4 to 6 This is a diagram showing the structural relationship between the inner side of the first carrier and the outer side of the second carrier.

[0032] Figure Labels

[0033] 1000: Actuator for cameras

[0034] 100: Housing; 110: Track rail

[0035] 120: Circuit board; 130: Yoke plate

[0036] 200: First carrier; 210: Guide rail

[0037] 221: First section 222: Second section

[0038] 223: Avoidance Space 224: Corresponding Surface

[0039] 300: Second carrier; 320: Corresponding outer side

[0040] 400: Housing; 500: Z-shaped stopper

[0041] R: Lens (lens assembly) M1: First magnet

[0042] M2: Second magnet M3: Third magnet

[0043] C1: First coil; C2: Second coil

[0044] C3: Third coil; H1: First Hall sensor (first operating driver)

[0045] H2: Second Hall sensor (second operating driver)

[0046] H3: First Hall sensor (third operating driver)

[0047] B1: First sphere; B2: Second sphere Detailed Implementation

[0048] Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. Before the description, it should be understood that the terminology used in the specification and appended claims should not be construed as limited to its general and dictionary meaning, but rather is interpreted based on the principle that inventors are allowed to appropriately define terms for the best interpretation, and on the meanings and concepts corresponding to the technical aspects of the present disclosure.

[0049] Therefore, the description presented herein is merely a preferred example for illustrative purposes and is not intended to limit the scope of this disclosure. It should be understood that other equivalents and modifications may be made thereto without departing from the scope of this disclosure.

[0050] Figure 1 This is a diagram showing the overall configuration of an actuator 1000 for a camera (hereinafter referred to as "actuator") according to a preferred embodiment of the present disclosure.

[0051] According to embodiments, the actuator 1000 of this disclosure can be implemented as a single device, or it can be implemented as a camera module including a lens assembly R, an image sensor (not shown), etc.

[0052] like Figure 1 As shown, the actuator 1000 of this disclosure is configured to include a housing 100, a first carrier 200, a second carrier 300, a Z-shaped stop 500, and a housing 400 serving as a shield, etc.

[0053] like Figure 1 As shown, the lens R (lens assembly) is mounted on the second carrier 300 (OIS carrier) housed within the first carrier 200 (AF carrier), and they move physically together. Therefore, if the first carrier 200 is in the optical axis direction ( Figure 1 If the lens moves back and forth along the Z-axis (e.g.), the lens R will also move along the optical axis.

[0054] If the lens R moves along the optical axis due to the movement of the first carrier 200 in the optical axis direction, the distance between the lens R and the image sensor (not shown) such as CCD or CMOS is adjusted, thereby realizing the autofocus function and zoom function.

[0055] In the following, in this disclosure, the directional axis corresponding to the path of light incident on the lens R (i.e., the directional axis corresponding to the direction perpendicular to the lens R) is defined as the optical axis (Z-axis), and two axes on the plane perpendicular to the optical axis (Z-axis) are defined as the X-axis and the Y-axis.

[0056] The drive unit for moving the first carrier 200 in the optical axis direction based on the housing 100 can employ various components such as shape memory alloy (SMA), piezoelectric elements and microelectromechanical systems (MEMS), but considering power consumption, noise suppression, space utilization, linear movement characteristics, precise control efficiency, etc., it is preferable to implement a configuration that uses the magnetic force generated between the magnet and the coil.

[0057] Specifically, in the preferred embodiments of this disclosure, such as Figure 1 As shown, the first magnet M1 is disposed on one side of the first carrier 200 (AF carrier), and the first coil C1 is disposed on the housing 100 facing the first magnet M1.

[0058] Since electromagnetic force is a relative force, the first coil C1 can be set to the first carrier 200 as the mover, and the first magnet M1 can be set to the housing 100 as the relative stator.

[0059] If power of appropriate magnitude and direction is applied to the first coil C1 under the control of the operating driver H1, a magnetic force is generated between the first coil C1 and the first magnet M1, and the first carrier 200 moves linearly in the optical axis direction by using the generated magnetic force as a driving force relative to the relative viewpoint of the housing 100, etc.

[0060] According to one embodiment, a detection sensor may also be included for detecting the position, orientation, etc., of the first carrier 200. In this case, if the detection sensor detects the position of the first carrier 200 and sends a corresponding signal to the operation driver H1, the operation driver H1 controls the power applied to the first coil C1 with corresponding magnitude and orientation.

[0061] The detection sensor can be implemented as a Hall sensor H1. The Hall sensor H1 uses the Hall effect to detect changes in the magnitude and direction of the magnetic field of the magnet in the detection area and outputs an electrical signal accordingly.

[0062] If the detection sensor is implemented as a Hall sensor as described above, the first Hall sensor H1 is configured to detect the magnitude and / or direction of the magnetic field of the first magnet M1 set to the first carrier 200 and output a corresponding signal.

[0063] The sensing and control processing of the first Hall sensor H1 and the operating driver are preferably configured to be applied cyclically through feedback control, so that the driving accuracy can be further improved through continuous control of the time series.

[0064] The operation driver can be implemented as a separate electronic component or device. However, since the operation driver is usually implemented as a single electronic component (chip) integrated with the Hall sensor via a SOC (System-on-Chip) or similar device, the first Hall sensor and the operation driver are represented by the same reference numeral H1 in the accompanying drawings.

[0065] The first sphere B1 is disposed between the housing 100 and the first carrier 200. To achieve effective linear guidance, the first sphere B1 is disposed on the outer side of the first carrier 200, and is preferably configured to partially accommodate a guide rail 210 disposed on the outer side of the first carrier 200 and having a shape extending in the optical axis direction (see...). Figure 2 (or at least one of the grooves 110 formed in the housing 100.)

[0066] If the first sphere B1 is configured as described above, the first carrier 200 can move more flexibly with minimal friction by means of the movement, rolling, point contact, etc. of the first sphere B1 while maintaining an appropriate distance between the first sphere B1 and the housing 100. Therefore, noise can be reduced, driving force can be minimized, and driving accuracy can be further improved.

[0067] According to one embodiment, the housing 100 of this disclosure may include a yoke 130. The yoke 130 is configured to generate an attractive force with a first magnet M1. Because the first carrier 200, including the first sphere B1, is pulled towards the housing 100 due to the attractive force between the yoke 130 and the first magnet M1... Figure 1 (in the X-axis direction), so point contact can be continuously maintained between the first sphere B1 and the first carrier 200, and between the first sphere B1 and the shell 100.

[0068] The first coil C1, the first Hall sensor H1, the second coil C2 (described later), and the third coil C3 (described later) are mounted on a circuit board 120 that is interconnected with an external module or power interface.

[0069] According to this disclosure, the actuator 1000 for a camera may include a Z-shaped stop 500, which, according to an embodiment, restricts the movement of a second carrier 300, etc., in the Z-axis direction and guides the movement of the second carrier 300 in a first direction and / or a second direction, so as to suppress deviations of the second carrier 300 in the Z-axis direction, such as gapping or lifting, when driving the OIS.

[0070] Figure 2 and Figure 3 This is a diagram illustrating the specific construction of the first carrier 200 and the second carrier 300 according to a preferred embodiment of the present disclosure.

[0071] like Figure 2As shown, a second carrier 300 (OIS carrier) that moves in a direction perpendicular to the optical axis (X-axis, Y-axis or a combination thereof) is configured to be housed inside the first carrier 200.

[0072] The second magnet M2 and the third magnet M3 are mounted on the side surface of the second carrier 300 to enable movement in each direction perpendicular to the optical axis (X-axis direction and Y-axis direction), and the second coil C2 and the third coil C3 facing the second magnet M2 and the third magnet M3 respectively are disposed in the housing 100.

[0073] The second carrier 300 moves based on the first carrier 200. For example... Figure 2 As shown, the second carrier 300 can be moved by a second sphere B2 disposed between the first carrier 200 and the second carrier 300, and according to the embodiment, the second carrier 300 can also be moved by an elastic member such as a wire or a spring.

[0074] As described above, the second carrier 300 can be moved in each direction by the driving force generated by the electromagnetic force between the second magnet M2 and the second coil C2 and between the third magnet M3 and the third coil C3.

[0075] Specifically, when the second Hall sensor H2 detects vibration in the X-axis direction and outputs a signal corresponding to the vibration, the operator driver H2 controls the application of power of appropriate magnitude and direction to the second coil C2, so that the second carrier 300 moves in the direction of the vibration-calibrated movement.

[0076] If power of appropriate magnitude and direction is applied to the second coil C2, such that a magnetic force is generated between the second coil C2 and the second magnet M2, the second carrier 300 moves linearly relative to the first carrier 200 in the X-axis direction.

[0077] According to this embodiment, when a magnetic force is generated between the second coil C2 and the second magnet M2 by adjusting the magnetic pole direction of the second magnet M2 and the arrangement direction of the second coil C2, the second carrier 300 can also be configured to move linearly in the Y-axis direction.

[0078] A series of processes, such as detection by the second Hall sensor H2, control by the second operation driver H2, generation of magnetic force between the second coil C2 and the second magnet M2, and reverse movement of the second carrier 300, are configured to be applied in a time-series and cyclic manner, thereby continuously correcting hand tremors.

[0079] The method of correcting hand tremors in the Y-axis direction using the third coil C3, the third Hall sensor H3, and the third operation driver H3 also corresponds to this method, so it will not be described in detail here.

[0080] According to the implementation, the second carrier 300 can also be implemented as multiple carriers that can move individually in each of the X-axis and Y-axis directions.

[0081] Figures 4 to 6 This is a diagram showing the structural relationship between the inner side of the first carrier 200 and the outer side of the second carrier 300.

[0082] As described above, the second carrier 300 corresponds to a mover housed inside the first carrier 200 and moving relative to the first carrier 200 in a direction perpendicular to the optical axis, and based on the movement of the second carrier 300, the first carrier 200 corresponds to a stator.

[0083] In order for the second carrier 300 to move in a combination of two directions perpendicular to the optical axis (X-axis direction and Y-axis direction), a movement space as large as the movement distance of the OIS of the second carrier 300 can be formed between the first carrier 200 and the second carrier 300.

[0084] According to the implementation, a magnetic structure can be implemented to center the reference position of the second carrier 300, but this is not for suppressing external forces. Since the magnetic structure used to center the reference position is small compared to the impact force generated externally, if a drop or collision occurs, the second carrier 300 will impact the inner surface of the first carrier 200.

[0085] Additionally, for example, when the action of shaking the smartphone is performed to pop up a QR code for user authentication, the second carrier 300 strongly and repeatedly impacts the inside of the first carrier 200 because the amount of shaking is much larger than the hand tremors that inevitably occur when taking an image.

[0086] If an external shaking, falling, collision, or impact occurs as described above, the second carrier 300 will generate a strong impact on the inside of the first carrier 200, and the force generated by the impact will be transmitted to the track structure (the structure for guiding the ball) located on the outside of the first carrier 200.

[0087] If the impact force is transmitted to the track structure as described above, since the track structure guiding the ball is in contact with the ball made of a material with high hardness (metal, ceramic, etc.), from a relative point of view, the damage will not occur at the ball, but at the surface of the track structure and the like that in contact with the ball (point contact).

[0088] In this disclosure, in order to solve the problem, even if the second carrier 300 located on the inside impacts the outside of the first carrier 200, the second carrier 300 is guided so that the second carrier 300 and the first carrier 200 make physical contact (collision) at the part other than the part where the guide rail 210 is provided.

[0089] Specifically, the actuator 1000 according to this disclosure is configured such that a first interval D1 (see [reference]) serves as the interval between the first segment 221 and the outer side 320 of the second carrier 300. Figure 5 The second interval D2, which is the interval between the outer sides of the second segment 222 and the second carrier 300, is greater than (see...). Figure 5 The first section 221 is the inner side of the first carrier 200 corresponding to the portion of the guide rail 210 located on the outer side, and the second section 222 is the inner side of the first carrier 200 adjacent to the first section 221 located on the inner side of the first carrier 200.

[0090] The corresponding outer side 320 of the second carrier 300 means the outer side of the second carrier 300 facing the inner side of the first carrier 200 where the guide rail 210 is provided.

[0091] In this configuration, even if the second carrier 300 impacts the first carrier 200 towards the guide rail 210, the impact will not be transmitted or propagated to the part where the guide rail 210 is located. Therefore, the problem of damage to the guide rail 210 in contact with the first ball B1 due to the transmission of external impact can be effectively avoided.

[0092] According to one embodiment, the first segment 221 and the second segment 222 are configured to have protruding shapes toward the corresponding outer side 320 of the second carrier 300, and the protruding size of the first segment 221 may be smaller than the protruding size of the second segment 222.

[0093] In the corresponding viewpoint, the portion of the corresponding outer side 320 of the second carrier 300 facing the second segment 222 can also be configured to be further separated into a concave shape, etc., instead of the portion facing the first segment 221.

[0094] From a practical perspective, the second carrier 300 can move only in the X-axis direction (based on the drawing, towards the first carrier 200 equipped with guide rail 210), or it can move simultaneously in the X-axis and Y-axis directions. Furthermore, the second carrier 300 can move in the X-axis direction immediately after moving in the Y-axis direction, and it can also move in the rotational direction through a combination of movements.

[0095] If the first interval D1 is configured to be greater than the second interval D2 (ΔD) as described above, see Figure 6 Therefore, even if the second carrier 300 moves in any direction, the impact force can be effectively suppressed from being transmitted to the part with the guide rail 210.

[0096] More preferably, an avoidance space 223 can be formed between the first segment 221 and the second segment 222. If the avoidance space 223, which serves as a free space between the first segment 221 and the second segment 222, is formed as described above, even if the second carrier 300 rotates or moves in the +X axis direction immediately after moving in the +Y axis direction, the phenomenon of the second carrier 300 colliding with the first segment 221 or being impacted by the first segment 221 can be suppressed.

[0097] Furthermore, if the avoidance space 223 is formed in this way, the force applied to the second section 222 is cut off by the avoidance space 223 and cannot be transmitted to the first section 221. Therefore, it can effectively prevent the first section 221 from being damaged by impacts applied to the second section 222.

[0098] In order to further maximize the physical avoidance relationship and more firmly realize the physical support structure of the guide rail 210, the avoidance space 223 is preferably configured to include a corresponding surface 224 formed toward the first section 221 and having a shape corresponding to the surface of the guide rail 210.

[0099] Additionally, as shown in the figure, the edge portion E of the second carrier 300 adjacent to the first segment 221 (see figure) Figure 5 More preferably, the second carrier 300 is configured to have an inclined or arc-shaped shape, thereby further reducing the possibility of physical contact (impact, collision, etc.) between the outer side of the second carrier 300 and the inner side of the first carrier 200 where the guide rail 210 is provided.

[0100] This disclosure has been described in detail. However, it should be understood that although preferred embodiments of this disclosure have been pointed out, the detailed description and specific examples are given by way of illustration only, as various changes and modifications within the scope of this disclosure will become apparent to those skilled in the art based on this detailed description.

[0101] In the above description of this specification, terms such as “first” and “second” are merely conceptual terms used to identify components relative to each other, and therefore should not be interpreted as terms used to indicate a particular order, priority, etc.

[0102] To emphasize or highlight the technical content of this disclosure, the accompanying drawings used to illustrate this disclosure and its embodiments may be shown in a slightly exaggerated manner. However, it should be understood that those skilled in the art can make various modifications in light of the above description and the accompanying drawings without departing from the scope of the invention.

Claims

1.An actuator for a camera, the actuator for a camera comprising: a first carrier configured to move in an optical axis direction and having a guide rail formed to extend in the optical axis direction and a first magnet disposed at an outer side of the first carrier; a second carrier configured to move in a direction perpendicular to the optical axis and accommodated at an inner side of the first carrier; a housing configured to accommodate the first carrier; and a ball disposed between the guide rail and the housing, and wherein the first carrier includes a first section, a second section, and an avoidance space, the first section is disposed at an inner side where the guide rail is formed, the second section is disposed at a left side or a right side of the first magnet and disposed at the same inner side as the first section but in a portion of the inner side where the first section is not disposed, and the avoidance space is a groove formed on the inner side of the first carrier between the first section and the second section to physically disconnect the first section and the second section, wherein a first interval defined as an interval between the first section and an outer side of the second carrier is greater than a second interval defined as an interval between the second section and the outer side of the second carrier. 2.The actuator for a camera according to claim 1, the avoidance space includes a corresponding surface disposed toward the first section and having a shape corresponding to a surface of the guide rail. wherein 3.The actuator for a camera according to claim 1, the first section and the second section have a shape protruding toward the outer side of the second carrier, and a protruding size of the first section is smaller than a protruding size of the second section. wherein 4.The actuator for a camera according to claim 1, an edge portion of the second carrier adjacent to the first section has an inclined shape or an arc shape. wherein 5.A camera module including the actuator for a camera according to any one of claims 1 to 4. ​

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