Zoom drive actuator and position control method for zoom drive

Abstract

A zoom drive actuator according to the present application includes a first carrier having a first lens mounted thereto and moving in an optical axis direction, a second carrier having a second lens mounted thereto and moving in the optical axis direction above or below the first carrier with respect to the optical axis direction, a housing receiving the first carrier and the second carrier therein, a first magnet mounted to the first carrier, a second magnet mounted to the second carrier, a first coil portion disposed in the housing and facing the first magnet, a second coil portion disposed in the housing and facing the second magnet, and a ball disposed between the housing and the first carrier and between the housing and the second carrier, respectively.

Description

Technical Field

[0001] This disclosure relates to zoom actuators and methods for position control. More specifically, among other things, this disclosure relates to an actuator capable of driving a lens with improved accuracy over an extended stroke. Background Technology

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

[0003] In recent years, actuators for zoom lenses have been seen that support variable adjustment features, including object size, by adjusting the focal length through functions such as zooming in and zooming out. In some actuator models, further diversification of zoom capabilities is achieved through combinations of the relative positions of multiple lenses (lens assemblies).

[0004] Because zoom lenses have a longer or extended travel distance (also known as stroke) along the optical axis compared to ordinary lenses, the actuators used to drive zoom lenses must be designed accordingly to apply sufficient driving force. Furthermore, their design should allow for accurate detection and feedback control of corresponding positions of the zoom lens across its entire stroke range.

[0005] However, actuators known in the art have elements for driving multiple but independent carriers that are simply mounted. Therefore, although they have the capability of lens-based relative positioning (e.g., zooming and autofocus), they are limited by their reliance on the conventional application of Hall sensors and are lacking in the ability to accurately detect the position of the carrier (lens) of interest and to use this information for feedback control over extended movement distances.

[0006] Furthermore, while known actuators in the art have achieved some success in enhancing driving force by placing magnets at both ends of the carrier, this approach results in excessively large actuator sizes because space must be allocated for movement of each carrier element when designing the actuator space. Therefore, there are significant obstacles to using existing actuators in applications where size or volume is a critical issue, such as smartphones.

[0007] Furthermore, existing actuators cannot precisely control the actuation of individual carriers, especially in the spacing where multiple carriers are close together. Existing actuators are configured to include multiple carriers, each with a magnet attached, and the magnet is positioned to face a coil for generating electromagnetic force within the magnet. This configuration leads to magnetic interference due to interaction with another coil or magnet, creating another unresolved technical problem. Summary of the Invention

[0008] Technical issues

[0009] This disclosure is conceived to address the aforementioned problems of the prior art within the above context. A technical objective of the present invention is to achieve more efficient utilization of actuator space. Another technical objective is to provide a zoom actuator capable of accurately detecting position over an extended travel range, resulting in improved zoom drive accuracy through multiple interactive Hall sensors.

[0010] These and other objects and advantages of this disclosure will be understood from the following detailed description and will become more fully apparent from the exemplary embodiments of this disclosure. Furthermore, it will be readily understood that the objects and advantages of this disclosure may be achieved by the means set forth in the appended claims and combinations thereof.

[0011] Technical solution

[0012] To achieve the aforementioned technical objectives, one aspect of this disclosure provides a zoom actuator comprising: a first carrier attached to a first lens and movable along an optical axis; a second carrier attached to a second lens, the second carrier being movable along an optical axis and moving in front of or behind the first carrier; a housing surrounding the first and second carriers; a first magnet attached to the first carrier; a second magnet attached to the second carrier; a first coil unit mounted to the housing and facing the first magnet; a second coil unit mounted to the housing and facing the second magnet; and a plurality of balls, wherein at least one of the plurality of balls is located between the housing and the first carrier, and at least one of the plurality of balls is located between the housing and the second carrier.

[0013] In a particular embodiment, the first carrier includes: a first base equipped with a first lens; and a first bracket mounted on the left or right side of the first base, the first bracket extending longer along the optical axis than the first base. Similarly, the second carrier includes: a second base equipped with a second lens; and a second bracket mounted on the left or right side of the second base, but opposite to the side on which the first bracket is mounted, the second bracket extending longer along the optical axis than the second base in a direction opposite to that of the first carrier.

[0014] In a preferred embodiment, the first or second coil unit is arranged in front of or behind each other along the optical axis. n Composed of ( ) coils n (A natural number equal to or greater than 2). In this case, the first or second magnet is oriented towards the first coil unit or the second coil unit, respectively. n+ It consists of one magnetic pole.

[0015] Additionally, the first carrier of this disclosure may further include: a first track formed on the first support; and a second track formed on the area of ​​the first base where the first support is not assembled, while the second carrier may further include: a third track formed on the second support; and a fourth track formed on the area of ​​the second base where the second support is not assembled.

[0016] In this configuration, the housing of this disclosure may include: a first guide rail formed of a plurality of individual rails and facing the first rail; a third guide rail formed of a plurality of individual rails and facing the third rail; a second guide rail and a fourth guide rail; each of the second and fourth guide rails facing the second and fourth rails respectively, wherein one of the plurality of balls may be spatially inserted across each of the first to fourth rails according to each of the respective first to fourth guide rails.

[0017] Furthermore, in a preferred embodiment, each of the first to fourth guide rails is aligned parallel to the optical axis. In this case, the first guide rail is formed on one side of the housing, either the left or right side, the third guide rail is formed on the other side of the housing where the first guide rail is not mounted, and the second guide rail is formed inside the third guide rail, while the fourth guide rail is formed inside the first guide rail.

[0018] Preferably, the zoom actuator of this disclosure further includes a plurality of Hall sensors disposed along the optical axis at positions shifted at different distances from the interpole boundary of the first magnet.

[0019] In this particular embodiment, the plurality of Hall sensors of the present disclosure are preferably arranged on a line extending parallel to the optical axis, wherein the Hall sensors are positioned in front of or behind each other relative to the optical axis.

[0020] In another embodiment, the first magnet of this disclosure may be oriented towards the first coil unit. m Composed of magnetic poles ( m (where 3 is a natural number equal to or greater than 3), in which case multiple Hall sensors are preferably configured to face together when the first carrier is in the default position. m The same magnetic pole among all magnetic poles.

[0021] Another aspect of this disclosure is a method for position control of a zoom actuator, wherein the zoom actuator includes: a first carrier attached to a first lens and a first magnet and movable along an optical axis; a second carrier attached to a second lens and a second magnet and movable along an optical axis in front of or behind the first carrier; a first coil unit facing the first magnet; a second coil unit facing the second magnet; and a plurality of Hall sensors facing the first magnet. This method includes the following steps: a signal input step for receiving an output signal from each of the plurality of Hall sensors; a position signal generation step for generating a position signal for the first carrier by performing an operation on the output signal; and a position control step for controlling the position of the first carrier using the position signal. In this case, the plurality of Hall sensors are positioned along the optical axis at locations displaced at different distances from the interpole boundary of the first magnet.

[0022] More preferably, the first magnet may be configured to face the first coil. m One magnetic pole ( m (where is a natural number equal to or greater than 3). In this case, when the first carrier is in the default position, the position signal generation step performs an addition operation on the position signal when multiple Hall sensors are facing the same magnetic pole of the first magnet, or a subtraction operation when each of the multiple Hall sensors is facing a different magnetic pole of the first magnet.

[0023] Beneficial effects

[0024] According to a preferred embodiment of this disclosure, the physical arrangement of multiple carriers in symmetrically opposite directions not only provides sufficient independent range of motion for each lens (lens assembly) attached to each carrier, but also enables the entire device to be realized in a more spatially compact structure and shape, thereby providing a device design that is best suited to minimize the overall space and thus make the mobile terminal thinner.

[0025] According to a preferred embodiment of this disclosure, a space for utilizing a magnet is provided in such a way that the carrier reference lens is attached asymmetrically to allow each carrier to be fitted with a magnet of sufficient size, thereby efficiently enhancing the driving force.

[0026] According to another embodiment of this disclosure, the magnets and coils that together generate driving force for each carrier are completely separated to one side and the other side to prevent the magnetic lines of force driving each carrier from interfering with each other across the entire stroke range, resulting in more precise and accurate driving performance.

[0027] Furthermore, according to this disclosure, by configuring the magnet to have three or more exposed magnetic poles and arranging multiple Hall sensors along the optical axis from front to back, such that each Hall sensor is displaced differently from the interpole boundary of the magnet, improved accuracy can be obtained in detecting the position of each lens-mounted carrier in motion and in subsequent feedback control of the position. 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 depicting the overall configuration of the zoom drive actuator and camera module according to a preferred embodiment of the present invention;

[0030] Figure 2 This is a diagram depicting the overall configuration of a zoom drive actuator according to a preferred embodiment of the present invention;

[0031] Figure 3 It is a diagram that details the configuration of the first carrier and the housing according to an embodiment of the present invention;

[0032] Figure 4 This is a diagram that details the configuration of the second carrier and the housing according to an embodiment of the present invention;

[0033] Figure 5 The guide rails formed on the shell are depicted;

[0034] Figure 6 The configuration of the tracks formed on the first and second carriers is depicted;

[0035] Figure 7 The positional relationship between a plurality of Hall sensors and magnets according to the present invention is shown;

[0036] Figure 8 A signal system is shown that operates on output signals from multiple Hall sensors;

[0037] Figure 9 This is a block diagram illustrating a detailed configuration of the position control unit according to an embodiment of the present invention;

[0038] Figure 10 This is a flowchart describing a position control method for zoom drive performed by the position control unit of the present invention. Detailed Implementation

[0039] The preferred embodiments of this disclosure will now be described in detail with reference to the accompanying drawings. Before the description, it should be understood that, based on the principle of allowing the inventors to appropriately define terminology for best explanation, the terminology used in the specification and appended claims should not be construed as limited to its general and dictionary meaning, but rather as interpreted based on its meaning and concept corresponding to the technical aspects of this disclosure.

[0040] Therefore, the description presented herein is merely a preferred example and is intended only to illustrate the point, 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.

[0041] Figure 1 The overall configuration of a zoom drive actuator (hereinafter referred to as "actuator") (100) and a camera module (1000) according to a preferred embodiment of the present invention is depicted.

[0042] The actuator (100) of the present invention can be implemented not only as a single, independent device, but also together with other components such as the reflectometer module (200) as follows: Figure 1 Part of the camera module (1000) shown.

[0043] As will be described in detail below, the actuator (100) of the present invention is used to perform autofocus or zoom by moving each of a plurality of carriers to which a lens (lens assembly) is attached in a linear motion along the optical axis.

[0044] A reflectometer module (200) positioned in front of the actuator (100) of the present invention (along the optical axis) reflects or refracts the optical path (Z1) of the object toward the path in the direction of the lens (Z). Thus, the light reflected or refracted toward the optical axis passes through a lens (lens assembly) mounted on the carrier and enters an image sensor such as a complementary metal-oxide-semiconductor (CMOS) or charge-coupled device (CCD).

[0045] The reflectometer module (200) for modifying the optical path may include a reflectometer (210) composed of one or a combination of a mirror and a prism. The reflectometer (210) may be composed of any material capable of modifying the path of incident light from the outside toward the optical axis, but glass is the preferred medium for high-performance optical properties.

[0046] The camera module (1000) of the present invention, including elements such as a reflectometer module (200), is configured to refract the path of light toward the lens. This allows the entire device to be arranged longitudinally along the mobile terminal rather than across its width, in order to keep the mobile terminal thin, thus making it optimal for miniaturization and thinning of the mobile terminal.

[0047] In some embodiments, the reflectometer (210) is configured to move in a rotational motion by the action of a driving device (e.g., a magnet and a coil) capable of generating a magnetic field. Thus, as the reflectometer (210) moves or rotates, light reflected (refracted) from the object by the reflectometer (210) is guided along the ±Y axis and / or ±X axis into the lens and image pickup element, thereby enabling correction of camera shake along the X axis and / or Y axis.

[0048] Therefore, the light from the object reflected by the reflectometer module (200) enters the first lens (60) and the second lens (70) equipped in the actuator (100), and the actuator (100) of the present invention performs functions such as zooming and autofocusing, thereby adjusting the position of each of the first lens (60) and the second lens (70) along the optical axis in combination.

[0049] In some embodiments, the fixed lens (50) may be positioned as follows: Figure 1 The actuator (100) shown is positioned in front of the optical performance such as the zoom ratio of the actuator (100).

[0050] As described below, the optical axis (Z-axis) is defined as the axis corresponding to the path of incident light, for example, entering the first lens (60), and the two axes spanning the plane perpendicular to the optical axis (Z-axis) are defined as the X-axis and the Y-axis.

[0051] Figure 2 The overall configuration of the actuator (100) according to a preferred embodiment of the present invention is shown.

[0052] like Figure 2 As shown, the actuator (100) of the present invention includes a housing (110) that is equivalent to a base frame for accommodating internal components, an outer shell (190) attached to the housing (110) and capable of serving as a shield, a first carrier (120), and a second carrier (130).

[0053] Each of the first carrier (120) with the first lens (60) attached and the second carrier (130) with the second lens (70) attached is equivalent to a moving body that moves linearly along the optical axis (Z-axis), while the housing (110) is equivalent to a fixed body.

[0054] exist Figure 2 In the embodiments shown, the second carrier (130) is disposed behind the first carrier (120) along the optical axis and maintains this arrangement when moving linearly along the optical axis.

[0055] As will be described below, the first carrier (120) is equipped with a first magnet (M1) and a first coil unit (C1) facing the first magnet (M1) and giving driving force is provided in the housing (110).

[0056] Once an appropriate amount and direction of power is applied to the first coil unit (C1) by the first operating driver (150A), an electromagnetic force is generated between the first coil unit (C1) and the first magnet (M1), and the generated force causes the first carrier (120) to move back and forth along the optical axis.

[0057] Similarly, once the second operating driver (150B) applies control to apply power of appropriate size and direction to the second coil unit (C2), the electromagnetic force generated between the second coil unit (C2) and the second magnet (M2) attached to the second carrier (130) causes the second carrier (130) to move linearly along the optical axis.

[0058] Although the accompanying drawings show a first carrier (120) with a first lens (60) attached and a second carrier (130) with a second lens (70) attached, this is only one possible example. Needless to say, depending on a particular embodiment, a greater number of lenses and carriers may be included.

[0059] For the sake of clarity, the number of carriers shown as included in the actuator (100) will be two in this example. Additionally, along... Figure 2 The carrier with the optical axis set in front will be designated as the first carrier (120), while the carrier set in the rear will be designated as the second carrier (130).

[0060] Therefore, as each of the first carrier (120) and the second carrier (130) moves linearly along the optical axis, so do the individual lenses attached to the respective carriers, and zooming or autofocus is achieved through the relative positioning of these lenses. As explained above, in some embodiments, a fixed lens (50) may be disposed in front of the first lens (60) to suit the optical performance or specifications of the actuator (100).

[0061] Furthermore, it is preferable to provide ball bearings between the first carrier (120) and the housing (110) and between the second carrier (130) and the housing (110) so as to allow the first carrier (120) and the second carrier (130) to move linearly with minimal friction.

[0062] Figure 3 and Figure 4 The configuration of the first carrier (120), the second carrier (130) and the housing (110) according to an embodiment of the present invention is shown in detail.

[0063] As described above, the first carrier (120) of the present invention, which is attached to the first lens (60), is a movable body that moves linearly along the optical axis. More specifically, the first carrier (120) includes a first base (121) equipped with the first lens (60) and a first support (123) that carries the first magnet (M1).

[0064] As shown, the first base (121) is shaped to mate with the first lens (first lens assembly) (60) so that it can mount the lens. In some embodiments, a housing (not shown) may be provided to the first base (121) to prevent the first lens (60) from being misaligned, for example, along the X-axis.

[0065] The first bracket (123) that carries the first magnet (M1) is fitted to the left or right side of the first base (121) and extends longer than the first base (121) along the optical axis as shown in the figure.

[0066] The first support (123) may be integrally formed with the first base (121), and as will be described later, in order to form a physical structure symmetrical to the second support (133) of the second carrier (130), it preferably has a shape extending along one of the optical axes (Z-axis).

[0067] Since the first support (123) of the present invention, as described above, has an elongated shape along the optical axis, it is able to carry a first magnet (M1) that is proportionally expanded in length while maintaining the overall size of the first carrier (120), which helps to enhance the driving force.

[0068] The first coil unit (C1) mounted to the housing (110) is preferably arranged along the optical axis at the front or rear. n The system consists of several coils to increase the driving force. Preferably, the first magnet (M1) is configured accordingly to have a face facing the first coil unit (C1). n+ One magnetic pole. (In this article) n It is a natural number that is equal to or greater than 2.

[0069] As an implementation method Figure 3 The diagram shows a configuration including a first coil unit (C1) consisting of two separate coils and a first magnet (M1) with three magnetic poles facing the first coil unit (C1).

[0070] As described above, arranging the first magnet (M1) with more magnetic poles than the number of individual coils facing them enhances driving efficiency by continuously transmitting the magnetic force of the coils to the magnet, because this arrangement keeps the first coil unit (C1) facing two or more magnetic poles even when the first carrier (120) moves along the optical axis. It will be apparent that the same arrangement applies to the second magnet (M2) combined with the second coil unit (C2) driving the second carrier (13).

[0071] like Figure 3 As shown, the first Hall sensor (140A-1) and the second Hall sensor (140A-2) are components mounted on the first circuit board (170-1) together with the first coil unit (C1) and the first operating driver (150A). Through the Hall effect, the sensor detects the magnitude and direction of the magnetic field generated from the first magnet (M1) facing the sensor and generates an output signal corresponding to the magnetic field.

[0072] The first operating driver (150A) controls the processing of the output signals received from the first Hall sensor (140A-1) and the second Hall sensor (140A-2) by performing an operation on them, such that an electric current of a magnitude and direction commensurate with the result of the operation is applied to the first coil unit (C1). The first Hall sensor (140A-1) and the second Hall sensor (140A-2) will be described in detail below.

[0073] The second carrier (130) has a physical structure that is compatible with the first carrier (120) and is formed symmetrically in the opposite direction to the first carrier (120) as shown in the figure.

[0074] More specifically, the second carrier (130) includes a second base (131) equipped with a second lens (70) and a second support (133) that carries the second magnet (M2).

[0075] The second support (133) of the second carrier (130) is mounted on the left or right side of the second base (131), but opposite to the side on which the first support (123) of the first carrier (120) is mounted. In addition, the second support (133) is shaped to extend longer than the second base (131) along the optical axis in the opposite direction to the first support (123) of the first carrier (120).

[0076] Therefore, the physical structures of the first carrier (120) and the second carrier (130) are generally similar. By positioning the first base (121) equipped with the first lens (60) and the second base (131) equipped with the second lens (70) (based on the Y-axis) on the middle portion, the carrier is configured to provide sufficient space for the first lens (60) and the second lens (70) to move.

[0077] Meanwhile, the first magnet (M1) and the second magnet (M2) used to drive the first carrier (120) and the second carrier (130) respectively can be set in a larger size through the first bracket (123) and the second bracket (133) in order to effectively enhance the driving force.

[0078] Furthermore, the first magnet (M1) and the second magnet (M2) are positioned separately to the left and right, respectively, based on the Y-axis. Correspondingly, the first coil unit (C1) and the second coil unit (C2), each facing the first magnet (M1) and the second magnet (M2), are also positioned separately.

[0079] As described, separating the first magnet (M1) and the first coil unit (C1) and the second magnet (M2) and the second coil unit (C2) far apart from each other allows the actuator of the present invention to eliminate interference and influence between the electromagnetic forces used to drive the respective carriers from the outset, resulting in more precise and independent driving of the first carrier (120) and the second carrier (130).

[0080] like Figure 3 As shown, the third Hall sensor (140B-1) and the fourth Hall sensor (140-B2) are components mounted on the second circuit board (170-2) together with the second coil unit (C2) and the second operation driver (150B). Through the Hall effect, the sensors detect the magnitude and direction of the magnetic field generated from the second magnet (M2) facing the sensor and generate an output signal corresponding to that magnetic field.

[0081] The second operating driver (150B) controls the processing of the output signals received from the third Hall sensor (140B-1) and the fourth Hall sensor (140B-2) by performing operations such that an electric current of a magnitude and direction commensurate with the result of the operation is applied to the second coil unit (C2).

[0082] Figure 5 The guide rails formed on the housing (110) are depicted, while Figure 6 The configuration of the tracks formed on the first carrier (120) and the second carrier (130) is depicted.

[0083] Figure 5 It is a cross-sectional view of the first, second, third and fourth guide rails (111, 112, 113, 114) exposed (based on the X-axis) on the bottom plate of the housing (110) in the YZ plane.

[0084] The first guide rail (111) and the second guide rail (112) are configured to guide balls (B1, B2) inserted between the first carrier (120) and the housing (110). Figure 5As shown, the first guide rail (111) is based on Figure 5 The Y-axis is formed to the right on the outside in multiple (preferably two) directions.

[0085] The first guide rail (111) is an element facing the first track (125) formed on the first support (123) of the first carrier (120) (see [link]). Figure 6 The first guide rail (111) has an overall elongated shape along the optical axis and is preferably implemented as a separate entity in multiple forms. A first ball bearing (B1) is inserted between the first rail (125) of the first support (123) and each of the individual first guide rails (111).

[0086] like Figure 6 As shown, the first carrier (120) includes a second track (127) formed on the area of ​​the first base (121) where the first bracket (123) is not assembled, and the second track (127) faces the second guide rail (112) formed on the housing (110).

[0087] like Figure 5 As shown, the second guide rail (112) is based on Figure 5 The Y-axis is formed to the left on the inner side. The second ball (B2) is inserted between the second guide rail (112) and the second track (127).

[0088] With the arrangement of a double-row first ball bearing (B1) inserted between the first track (125) and the first guide rail (111) and a second ball bearing (B2) inserted between the second track (127) and the second guide rail (112), the first carrier (120) contacts the housing (110) in a total of three positions.

[0089] This guiding arrangement of the first ball (B1) and the second ball (B2) is coordinated with the physical structure of the first support (123) which has an elongated shape along the optical axis, and as a whole provides more stable physical support for the first carrier (120).

[0090] like Figure 6 As shown, the second carrier (130) of the present invention includes a third track (135) formed (based on the X-axis) in the lower part of the second support (133) to which the second magnet (M2) is attached, and a fourth track (137) formed (based on the X-axis) in the lower part of the region of the second base (131) where the second support (133) is not provided.

[0091] The third guide rail (113) is an element facing the third track (135) formed on the second support (133) and has an overall elongated shape along the optical axis, and is preferably implemented as a separate entity in multiples on the housing (110) to provide stable support as the first guide rail (111).

[0092] like Figure 5 As shown, the third guide rail (113) is based on Figure 5 The Y-axis is formed on the side that is further out and to the left relative to the second guide rail (112). The fourth guide rail (114) implemented on the housing (110) faces the fourth track (137) of the second carrier (130) and is formed on the side that is further inward than the first guide rail (111).

[0093] With the arrangement of a double-row third ball bearing (B3) inserted between the third rail (135) and the third guide rail (113) and a fourth ball bearing (B4) inserted between the fourth rail (137) and the fourth guide rail (114), the second carrier (130) contacts the housing (110) in a facing manner at a total of three positions.

[0094] This guiding arrangement of the third ball (B3) and the fourth ball (B4) is coordinated with the physical structure of the second support (133) which has an elongated shape along the optical axis, and as a whole provides more stable physical support for the second carrier (130).

[0095] As previously described, the first carrier (120) and the second carrier (130) of the present invention are separated into a region for attaching a lens and another region for attaching a magnet, wherein the magnet attachment region has an elongated shape along the optical axis. The first carrier (120) and the second carrier (130) are physically arranged symmetrically in opposite directions.

[0096] As conceived above, the present invention allows for a guide rail configuration extending along the optical axis, which in turn provides a more efficient means of extending the travel range of the first carrier (120) and the second carrier (130) along the optical axis without interference or physical disturbance.

[0097] To achieve effective linear guidance along the path, it is preferable that at least one or more rails (125, 127, 135, 137) and / or guide rails (111, 112, 113, 114) accommodate some balls (B1, B2, B3, B4).

[0098] Figure 7 The positional relationship between a plurality of Hall sensors and a magnet according to the present invention is shown. Figure 8 The diagram shows the output signals from multiple Hall sensors and the signaling system calculated from them.

[0099] The present invention will now be described based on an embodiment including a first magnet (M1) and a first Hall sensor (140A-1) and a second Hall sensor (140A-2) for detecting the position of the first magnet (M1). However, it will be apparent that this description is equally applicable to embodiments including a second magnet (M2) and a third Hall sensor (140B-1) and a fourth Hall sensor (140B-2) for detecting the position of the second magnet (M2).

[0100] As is well known in the art, Hall sensors detect the magnitude and direction of a magnetic field from a magnet they are facing and output a proportional electrical signal based on the Hall effect.

[0101] This means that when the Hall sensor is placed in the middle of a specific magnetic pole (N or S), the output signal of the Hall sensor will respond less to changes in the moving magnet, while when the Hall sensor is placed at the boundary between the poles of the magnet, the change will be larger.

[0102] Furthermore, in applications such as high-magnification zoom involving extended movement of the carrier, the same extended movement applies to magnets attached to those carriers, such that a Hall sensor mounted in a fixed position faces the entire area of ​​the moving magnet, including the middle portion and the boundaries of the magnetic poles.

[0103] Therefore, depending on the range and position of the magnet (carrier), detecting the exact position of the magnet becomes achievable within a specific range where there are clear differences in signal values, but not in other ranges where the differences are less clear. When detecting the exact position of the magnet thus becomes impossible, precise position control for zooming or autofocus also becomes impossible.

[0104] To effectively solve this problem, the present invention includes, as follows: Figure 7 The Hall sensor shown detects the position of the first magnet (M1). More specifically, multiple Hall sensors are arranged along the optical axis from the magnetic pole boundary of the first magnet (M1). Figure 7 (A1 and A2) are shifted to different distances.

[0105] In addition, the first operating driver (150A) of the present invention is configured to generate position information of the first magnet (M1) through the collective output signal from the plurality of Hall sensors and control the driving of the first carrier (120) based on the information.

[0106] Although the two Hall sensors in the accompanying drawings, the first Hall sensor (140A-1) and the second Hall sensor (140A-2), represent multiple Hall sensors, this is only one possible example. Needless to say, a greater number of Hall sensors may be included depending on the specific implementation.

[0107] More specifically, the Hall sensor is configured to such that... Figure 7 As shown in the middle plan view, the second Hall sensor (140A-2) is positioned near the inter-electrode boundary (A1) (S1), and the first Hall sensor (140A-1) is positioned further away from the same inter-electrode boundary (A1) than the second Hall sensor (140A-2) (S2).

[0108] In order to achieve accurate processing of the collective output signals from the first Hall sensor (140A-1) and the second Hall sensor (140A-2), the first Hall sensor (140A-1) and the second Hall sensor (140A-2) are aligned parallel to the optical axis and are positioned in front of or behind each other.

[0109] The output signals from the first Hall sensor (140A-1) and the second Hall sensor (140A-2) when the first magnet (M1) moves are shown in the figure. Figure 8 (a) and Figure 8 In (b), the premise is that the default position of zoom or autofocus drive is as follows: Figure 7 As shown, when zooming or autofocusing is driven by the first operation driver (150A), the first magnet (M1) moves along the Z-axis in the increasing direction.

[0110] When the first magnet (M1) begins to move along the increasing direction of the Z-axis, the signal change detected by the first Hall sensor (140A-1) in region T1 is relatively small because the first Hall sensor (140A-1) faces the middle portion of the magnetic pole (N) of the first magnet (M1). However, because the second Hall sensor (140A-2) is positioned close to the inter-pole boundary (A1) of the first magnet (M1), the signal change detected in region T1 is relatively large.

[0111] Furthermore, as the first magnet (M1) continues to move along the increasing Z-axis, the situation reverses, and the first Hall sensor (140A-1) moves closer to the inter-pole boundary (A1), while the second Hall sensor (140A-2) moves away from the inter-pole boundary (A1) and faces the middle portion of another, closer magnetic pole (S). Therefore, relatively speaking, the signal change in region T2 becomes more pronounced for the first Hall sensor (140A-1), but less pronounced for the second Hall sensor (140A-2).

[0112] Therefore, by configuring the zoom actuator to determine the position of the first magnet (M1) by referring to the output signal from the second Hall sensor (140A-2) for region T1 and the output signal from the first Hall sensor (140A-1) for region T2, accurate positioning of the first magnet (M1) across the entire stroke range can be achieved.

[0113] In addition, through such Figure 8 The circuit configuration shown in (c) or the implementation of the driving mechanism to perform (addition or subtraction, etc.) operations on the output signals from the first Hall sensor (140A-1) and the second Hall sensor (140A-2) can achieve higher data processing efficiency by eliminating supplementary steps (e.g., physically or by separating regions with electrical signals).

[0114] Figure 7 The implementation depicted at the bottom is equivalent to the implementation in which the first Hall sensor (140A-1) is shifted S1 from the first inter-electrode boundary (A1), and the second Hall sensor (140A-2) is shifted S2 from the second inter-electrode boundary (A2) (S2>S1).

[0115] In this arrangement where each Hall sensor is shifted a different distance from its respective inter-electrode boundary, the output signals from the Hall sensors differ only in sign (positive or negative), while their magnitudes are the same as in the example described above, resulting in an implementation of the same inventive concept described above.

[0116] Therefore, the present invention is intended to cover any embodiment in which the first Hall sensor (140A-1) and the second Hall sensor (140A-2) are configured to be shifted by different lengths from the magnetic pole boundaries (A1, A2), and should not be construed as limited to Figure 7 The example shown.

[0117] In some embodiments, the first magnet (M1) is configured to face the first coil unit (C1). m One magnetic pole, and multiple Hall sensors (i.e., the first Hall sensor (140A-1) and the second Hall sensor (140A-2)) are configured to face the first carrier (120) when it is in the default position. m The same magnetic pole is set among the magnetic poles. Here m It is a natural number that is equal to or greater than 3.

[0118] In this embodiment, the first coil unit (C1) facing the first magnet (M1) can also be configured as a twin coil, namely, a first sub-coil (C1-1) and a second sub-coil (C1-2).

[0119] This twin-coil arrangement results in enhanced driving efficiency, wherein the first magnet (M1) can be expanded in response to the extended stroke of the first carrier (120), and driving force can be obtained by utilizing the interaction between the first sub-coil (C1-1) and the second sub-coil (C1-2) facing different magnetic poles respectively.

[0120] Furthermore, by eliminating steps such as setting a default position for the first carrier (120) based on output signals from the first Hall sensor (140A-1) and the second Hall sensor (140A-2), the efficiency of position detection and feedback position control can be improved, since when the first carrier (120) is set to the default position, the two Hall sensors together face the same magnetic pole of the first magnet (M1).

[0121] Figure 9 This is a block diagram illustrating a detailed configuration of the position control unit (300) according to an embodiment of the present invention. Figure 10 This is a flowchart describing a position control method for zoom drive performed by the position control unit (300) of the present invention.

[0122] The previously shown example can be described as an implementation in which the actuator drives the first carrier (120) and the second carrier (130) along the optical axis, while the following description applies to the position control unit (300) of the present invention, which, as previously described, can be mounted on the actuator and, in some embodiments, can be implemented in the form of a first operating driver (150A) or a second operating driver (150B).

[0123] The position control unit (300) according to the present invention, as shown in the figure Figure 9 The components shown should be understood as logically separate rather than physically separate components.

[0124] In other words, each implementation is equivalent to a logical component for realizing the technical concept of the present invention. Any implementation (whether as a whole or composed of individual elements) capable of performing the functions performed by the logical settings of the present invention should be considered within the scope of the present invention. Any element that performs the same or similar functions as the present invention should also be interpreted as being within the scope of the present invention, regardless of whether their names are the same.

[0125] like Figure 9 As shown, the position control unit (300) of the present invention may include an input unit (310), a signal generation unit (320), a database (DB) unit (330), and a drive control unit (340).

[0126] As described above, the input unit (310) corresponds to an interface for receiving signals from multiple Hall sensors (S910), with an exemplary configuration being a first Hall sensor (140A-1) and a second Hall sensor (140A-2).

[0127] As shown in the figure, in some embodiments, the input unit (310) of the present invention may be configured to receive signals (S910) from a plurality of Hall sensors (140A-1, 140A-2, ...) positioned facing the first magnet (M1). In this case, the position control unit (300) of the present invention may be configured to generate a position signal of the first carrier (120) using all of the plurality of signals or a combination of selected signals.

[0128] It will be apparent that the following description of the position control of the first carrier (120) with reference to the first magnet (M1), the first coil unit (C1), and the first Hall sensor (140A-1) and the second Hall sensor (140A-2) for detecting the first magnet (M1) applies to the position control of the second carrier (130) with reference to the second magnet (M2), the second coil unit (C2), and the third Hall sensor (140B-1) and the fourth Hall sensor (140B-2) for detecting the second magnet (M2).

[0129] When the input unit (310) receives (S910) the output signal (first signal) from the first Hall sensor (140A-1) and the output signal (second signal) from the second Hall sensor (140A-2) via the interface, the signal generation unit (320) of the present invention generates a position signal (S950) about the current position of the first carrier (120) by performing operations on these first and second signals.

[0130] More specifically, when the first carrier (120) is set in the default position and multiple Hall sensors (first Hall sensor (140A-1) and second Hall sensor (140A-2)) face the same magnetic pole of the first magnet (M1) together, a position signal is generated by processing the output signals (first signal and second signal) of each Hall sensor based on an addition operation (S930) (S950).

[0131] On the other hand, when the first carrier (120) is set in the default position and multiple Hall sensors (first Hall sensor (140A-1) and second Hall sensor (140A-2)) face different magnetic poles of the first magnet (M1), a position signal is generated by processing the output signals (first signal and second signal) of each Hall sensor based on a subtraction operation (S940) (S950).

[0132] The database (DB) unit (330) of the present invention can store DB information (S900), such as a lookup table that associates the code values ​​of the electrical signals output from each Hall sensor with control value information about the magnitude and direction of the power transmitted to the first coil unit (C1-1, C1-2) based on the specification information of the first Hall sensor (140A-1), the second Hall sensor (140A-2), and the first coil unit (C1-1, C1-2).

[0133] The processing of the operation of the first and second signals can be implemented in hardware, such as by a circuit electrically connecting the first Hall sensor (140A-1) and the second Hall sensor (140A-2). It will be apparent, according to an embodiment, that the processing can alternatively be implemented by the circuit design of the first operation driver (150A) or by software installed on the first operation driver (150A).

[0134] When generating a position signal from the signal generation unit (320), the drive control unit (340) of the present invention accesses and reads the information stored in the database unit (330) and selects control value information corresponding to the position signal (S960).

[0135] When the control value information is selected as described above, the drive control unit (340) of the present invention controls the application of power to the first coil unit (C1, C1-1, C1-2) with a size and direction corresponding to the control value information, so as to control the position or movement of the first carrier (120) (S970).

[0136] This disclosure has been described in detail. However, it should be understood that various changes and modifications within the scope of this disclosure will become apparent to those skilled in the art from this detailed description, so the detailed description and specific examples are given by way of illustration only while indicating preferred embodiments of this disclosure.

[0137] 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.

[0138] The accompanying drawings used to illustrate this disclosure and its embodiments may be shown in a slightly exaggerated manner to emphasize or highlight the technical content of this disclosure. However, it should be understood that various modifications can be made by those skilled in the art in consideration of the above description and the illustrations in the drawings without departing from the scope of the invention.

Claims

1. A zoom actuator, the zoom actuator comprising: A first carrier, wherein a first lens is attached to the first carrier and it is movable along the optical axis; A second carrier, the second carrier having a second lens attached thereto, the second carrier being able to move along the optical axis in front of or behind the first carrier; A housing that surrounds the first carrier and the second carrier; A first magnet is attached to the first carrier; A second magnet is attached to the second carrier; A first coil unit is mounted to the housing and faces the first magnet; A second coil unit is mounted to the housing and faces the second magnet; as well as A plurality of balls, wherein at least one of the plurality of balls is located between the housing and the first carrier, and at least one of the plurality of balls is located between the housing and the second carrier. The zoom actuator further includes multiple Hall sensors disposed along the optical axis at positions shifted at different distances from the inter-pole boundary of the first magnet. The first magnet has a shape facing the first coil unit. m One magnetic pole, m It is a natural number equal to or greater than 3, and The plurality of Hall sensors are configured to face the first carrier together when the first carrier is in its default position. m The same magnetic pole among all magnetic poles.

2. The zoom actuator according to claim 1, in, The first carrier includes a first base equipped with the first lens; and A first bracket is installed on the left or right side of the first base, and the first bracket extends longer than the first base along the optical axis.

3. The zoom actuator according to claim 2, in, The second carrier includes a second base equipped with the second lens; and The second bracket is installed on the left or right side of the second base, but opposite to the side where the first bracket is mounted. The second bracket extends longer than the second base along the optical axis in a direction opposite to the first carrier.

4. The zoom actuator according to claim 1, in, The first coil unit or the second coil unit consists of two coils arranged relative to each other along the optical axis, one in front and one behind. n Composed of several coils, n It is a natural number equal to or greater than 2; and Wherein, the first magnet or the second magnet is respectively facing the first coil unit or the second coil unit. n+ It consists of one magnetic pole.

5. The zoom actuator according to claim 3, wherein, The first carrier further includes: A first track, the first track being formed on the first support; and The second track is formed on the area of ​​the first base where the first bracket is not fitted, and The second carrier further includes: A third track, the third track being formed on the second support; and A fourth track is formed on the area of ​​the second base where the second support is not fitted, and The housing includes: A first guide rail and a third guide rail, each of the first guide rail and the third guide rail being formed by a plurality of separate rails and respectively facing the first rail and the third rail, and The second guide rail and the fourth guide rail, each of the second guide rail and the fourth guide rail respectively facing the second rail and the fourth rail, and At least one of the plurality of balls is configured to span the respective spaces of each of the first to fourth rails from the first track to the fourth rail.

6. The zoom actuator according to claim 5, in, Each of the first to fourth guide rails is aligned parallel to the optical axis, and The first guide rail is formed on one of the left or right sides of the housing, and the third guide rail is formed on the other side of the housing where the first guide rail is not located. The second guide rail is formed inside the third guide rail, and the fourth guide rail is formed inside the first guide rail.

7. The zoom actuator according to claim 1, in, The plurality of Hall sensors are arranged on a line extending parallel to the optical axis, and the plurality of Hall sensors are positioned in front of or behind each other about the optical axis.

8. A method for position control of a zoom actuator, the zoom actuator comprising a first carrier attached to a first lens and a first magnet and movable along an optical axis, a second carrier attached to a second lens and a second magnet, a first coil unit facing the first magnet, a second coil unit facing the second magnet, and a plurality of Hall sensors facing the first magnet, the second carrier being movable along the optical axis in front of or behind the first carrier. The method includes the following steps: A signal input step is used to receive an output signal from each of the plurality of Hall sensors; The position signal generation step is used to generate a position signal of the first carrier by performing an operation on the output signal; as well as A position control step is used to control the position of the first carrier using the position signal, and The plurality of Hall sensors are positioned along the optical axis at different distances shifted from the interpole boundary of the first magnet. The first magnet has a shape facing the first coil unit. m One magnetic pole, m It is a natural number equal to or greater than 3, and In the default position of the first carrier, the position signal generation step performs an addition operation on the position signal when the plurality of Hall sensors are facing the same magnetic pole of the first magnet, or performs a subtraction operation when each of the plurality of Hall sensors is facing a different magnetic pole of the first magnet.

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