Actuator for camera

Abstract

An actuator for a camera according to an embodiment of the present invention comprises: a carrier that moves in an optical axis direction; a magnet provided on the carrier and including a variable portion having different magnetic forces in the optical axis direction; a plurality of coils facing the magnet; a Hall sensor which faces the variable portion and outputs a signal corresponding to the position of the magnet; a main driver that generates and outputs a command control signal for controlling a current applied to one or more coils among the plurality of coils on the basis of an output signal of the Hall sensor; and one or more sub-drivers that control a current applied to one or more coils among the plurality of coils in accordance with the command control signal.

Description

Technical Field

[0001] The present invention relates to an actuator for a camera, and more particularly, to an actuator for a camera that effectively controls driving of a plurality of coils based on a minimum number of Hall sensors. Background Art

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

[0003] In addition, an actuator for a zoom lens has recently been disclosed, which is capable of changing the size of a subject in various ways, such as through zoom-in and zoom-out functions. An actuator has also been disclosed that, depending on the embodiment, can achieve AF and / or zoom functions in more ways by applying the relative positional relationship of multiple lenses (lens assemblies) in a combined manner.

[0004] In the case of this type of actuator for a zoom lens, the distance the lens moves along the optical axis (also called the stroke) is extended or expanded compared to conventional lenses. Therefore, sufficient driving force corresponding to the extended stroke must be ensured, and most importantly, the corresponding position of the zoom lens must be accurately sensed and feedback controlled throughout the entire stroke range.

[0005] To sense the position of a lens, etc., a Hall effect sensor is primarily used. This sensor detects the magnitude and direction of magnetic force and outputs a corresponding signal. In relation to the Hall effect sensor, the magnitude and direction of the magnetic force at the pole boundary of the magnet facing the Hall effect sensor are linear, but the magnetic force remains constant beyond that point. Therefore, the range or area in which the Hall effect sensor's output signal can be used to control the lens' position is limited to the pole boundary of the magnet.

[0006] In the case of an actuator with a long stroke range, the length of the stroke is longer than the area where a single Hall sensor can distinguish the change (magnitude / direction) of the magnetic force of the magnet through the signal system. Therefore, in order to ensure a signal system corresponding to the entire stroke, a method is applied to arrange multiple Hall sensors along the optical axis and comprehensively utilize the signals output from these Hall sensors.

[0007] However, this method requires the pre-installation of multiple Hall sensors, which not only increases installation costs but also complicates circuit design. In addition, a processor is required to post-process the signals output by the Hall sensors in a functional manner, which may reduce real-time responsiveness.

[0008] Furthermore, the driver used in such conventional embodiments must coordinate with multiple Hall sensors to uniformly control multiple coils, necessitating a redesigned and integrated manufacturing process tailored to product specifications and parameters. These fundamental factors can reduce manufacturing efficiency and lower price competitiveness. Furthermore, the integration of various functions occupies a relatively large volume, potentially leading to low space utilization and considerable complexity in mounting the circuit board. Summary of the Invention

[0009] Technical problems to be solved

[0010] The present invention is made to solve the problems described in the background technology mentioned above, and its purpose is to provide an actuator for a camera, which further expands the range of application that can be recognized by the Hall sensor by making the magnetic properties of the magnet differentiated according to the position. This not only significantly improves the adaptability to position perception with only a minimum number of Hall sensors, but also further improves space utilization by constructing the driver in a split manner.

[0011] Other purposes and advantages of the present invention will be understood through the following description and will be more clearly understood through the embodiments of the present invention.In addition, the purposes and advantages of the present invention can be achieved through the structures and combinations of structures appearing in the claims.

[0012] Means of solving the problem

[0013] An actuator for a camera according to an embodiment of the present invention for achieving the above-mentioned purpose may be constructed as follows: a carrier, which moves along the optical axis; a magnet, which is arranged on the carrier and includes a variable part having a differentiated magnetic force in the optical axis direction; a plurality of coils, which are opposite to the magnet; a Hall sensor, which is opposite to the variable part and outputs a signal corresponding to the position of the magnet; a main driver, which generates and outputs a command control signal, wherein the command control signal is used to control the current applied to one or more coils among the plurality of coils according to the output signal of the Hall sensor; and one or more sub-drivers, which control the current applied to one or more coils among the plurality of coils according to the command control signal.

[0014] The main driver of the present invention may include a coil control unit configured to control current applied to at least one of the plurality of coils.

[0015] The number of the plurality of coils of the present invention may be n, where n is a natural number greater than or equal to 2. In this case, the main driver may specifically include: an input unit into which the output signal from the Hall sensor is input; a main processing unit for analyzing the output signal; a coil control unit for controlling the current applied to m coils of the plurality of coils, where m is a natural number greater than or equal to 1; a signal generation unit for generating a command control signal for controlling the current applied to nm coils of the n coils; and a communication unit for outputting the command control signal to the sub-driver.

[0016] According to an embodiment, the sub-driver of the present invention may include: a second input unit to which the command control signal is input; and a second coil control unit to control the current applied to one or more coils among the plurality of coils according to the command control signal.

[0017] Preferably, the magnet may further include a second portion, which is arranged outside the variable portion and has the same magnetic force as that of the variable portion.

[0018] In addition, it is preferable that two or more coils among the plurality of coils of the present invention are configured to face the second portion.

[0019] Furthermore, the plurality of coils of the present invention may be grouped into a first group and a second group based on the Hall sensor, and the first group and the second group provide driving force to the magnet in an alternating order.

[0020] Effects of the Invention

[0021] According to a preferred embodiment of the present invention, even without a plurality of Hall sensors, it is possible to accurately sense the movement of the lens, and thus the present invention is particularly suitable for an actuator for a zoom lens having a long stroke.

[0022] Furthermore, according to an embodiment of the present invention, while maintaining accurate driving performance, the circuit configuration, data processing, and calculation processing can be implemented in a simpler form, thereby further improving the time response characteristics.

[0023] Furthermore, according to the present invention, the magnet is divided into a portion for generating driving force and a portion for realizing position sensing, thereby achieving both enhanced driving force and accurate position sensing.

[0024] According to another embodiment of the present invention, by dividing the driver that performs Hall sensor linkage and coil control into a main driver and a sub-driver according to its function, not only can the space utilization be further improved, but also the new chip design can be minimized, and the combined application or utilization of existing drivers can be realized, thereby improving price competitiveness and also improving the efficiency of the assembly process. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the present invention described later, serve to more effectively understand the technical ideas of the present invention. Therefore, the present invention should not be interpreted as being limited to the matters recorded in such drawings.

[0026] Figure 1 FIG. 1 is a diagram showing the overall structure of an actuator and a camera module according to an embodiment of the present invention;

[0027] Figure 2 FIG2 is a diagram showing the overall structure of an actuator and a camera module according to another embodiment of the present invention;

[0028] Figure 3 and Figure 4 1 is a diagram showing the overall structure of an actuator according to an embodiment of the present invention;

[0029] Figure 5 is a diagram showing a detailed configuration for driving control of a carrier;

[0030] Figure 6 is a diagram showing an embodiment of a magnet, a coil, and a driver;

[0031] Figure 7 is a block diagram showing a detailed configuration of a main driver, etc. according to an embodiment of the present invention;

[0032] Figure 8 1 is a diagram showing the structure of a magnet according to an embodiment of the present invention;

[0033] Figure 9 and Figure 10 is a diagram illustrating the structural relationship between a magnet and a Hall sensor according to a preferred embodiment of the present invention;

[0034] Figure 11 is a diagram illustrating signal characteristics of a Hall sensor according to an embodiment of the present invention;

[0035] Figure 12 and Figure 13 is a diagram illustrating the structure of another embodiment of a magnet according to the present invention;

[0036] Figure 14This is a diagram illustrating the signal relationship of a Hall sensor having a conventional magnetic structure. DETAILED DESCRIPTION

[0037] The following describes in detail preferred embodiments of the present invention with reference to the accompanying drawings. Prior to this, the terms and words used in this specification and claims should not be interpreted as having commonly used or dictionary-defined meanings. Instead, they should be interpreted as meanings and concepts consistent with the technical concepts of the present invention, based on the principle that the inventor can appropriately define the concepts of the terms in order to best describe his or her invention.

[0038] 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 cannot represent the entire technical concept of the present invention. It is understandable that for this application, there may be multiple equivalents and variations that can replace these.

[0039] The physical and electromagnetic structures of the camera actuator 100 according to one embodiment of the present invention will be described in detail below. A preferred embodiment of the present invention that utilizes magnets with differentiated magnetic forces at different locations to sense and control position will be described later.

[0040] Figure 1 and Figure 2 1 is a diagram showing the overall configuration of a camera actuator (hereinafter referred to as “actuator”) 100 and a camera module 1000 according to a preferred embodiment of the present invention.

[0041] The actuator 100 of the present invention can be implemented not only as a single device but also as Figure 1 and Figure 2 As shown, the camera module 1000 is implemented as including the reflector module 200 and the like.

[0042] As described later, the actuator 100 of the present invention is equivalent to an actuator that causes multiple carriers equipped with lenses (lens assemblies) to linearly move along the optical axis to achieve autofocus (AF) or zoom. It goes without saying that, depending on the embodiment, the actuator 100 of the present invention can also be configured to linearly move a single number of carriers along the optical axis.

[0043] The reflector module 200, which can be provided in front of the actuator 100 according to the present invention (in the optical axis direction), reflects or refracts the light path (Z1) of the subject toward the path in the lens direction (Z, in the optical axis direction). The light thus reflected or refracted toward the optical axis is directed toward the image sensor 30 (see FIG. 1 ) such as a CMOS or CCD through the lenses 60a, 60b, 70a, 70b provided on the carriers 120 and 130. Figure 2) incident.

[0044] The reflector module 200 for changing the path of light may include a reflector 210, which may be composed of one selected from a mirror or a prism, or a combination thereof. The reflector 210 may be implemented by various components capable of redirecting externally incident light toward the optical axis, but is preferably implemented by glass to improve optical performance.

[0045] The camera module 1000 of the present invention, which also includes the reflector module 200, is constructed in a manner that refracts the path of light and causes it to be incident along the direction of the lens. Therefore, the device itself can be set not along the thickness direction of the portable terminal but along the length direction, thereby optimizing the miniaturization and slimming of the portable terminal.

[0046] According to an embodiment, the reflector 210 may be configured by a magnet and coils C3a, C3b (see Figure 3 and Figure 4 ) such as a single drive unit that generates magnetic force and rotates. In this way, when the reflector 210 moves or rotates, the light of the subject reflected (refracted) by the reflector 210 moves in the ±Y direction and / or ±X direction, thereby correcting the X-axis and / or Y-axis direction caused by hand shake.

[0047] The light of the subject reflected by the reflector module 200 is incident on the lens 60a and the like arranged inside the actuator 100, and the actuator 100 of the present invention adjusts the various positions based on the optical axis direction of the first lens 70a, 70b and the second lens 60a, 60b in a combined manner, thereby realizing functions such as zoom or AF.

[0048] The axes shown in the drawings, the terms referring to the axes, and the terms such as upper, lower, front, rear, vertical, horizontal, etc. described with reference to the axes are obviously only used to indicate relative references for describing the embodiments of the present invention, rather than for specifying a certain direction or position from an absolute reference, and it goes without saying that they can change relatively depending on the position of the object as the subject or the position of the observer, the viewing direction, etc.

[0049] In the following description of the present invention, the direction axis corresponding to the path of light incident on the lens 60a, etc. is defined as the optical axis (Z axis), and two axes on a plane perpendicular to the optical axis (Z axis) are positioned as the X axis and the Y axis.

[0050] Figure 1 The embodiment in which the actuator 100 and the reflection module 200 are disposed together in the housing 110 is shown, but according to the embodiment, the actuator 100 and the reflection module 200 may also be disposed together in the housing 110. Figure 2In this way, it goes without saying that the actuator 100 and the reflection module 200 are implemented in an assembled form.

[0051] in addition, Figure 1 The embodiment in which a plurality of lenses are mounted on the first carrier 120 and the second carrier 130 is shown. Figure 2 As illustrated, a single number or different numbers of lenses may be mounted on each carrier. Depending on the embodiment, more than one fixed lens 50 may be provided to meet the optical performance or parameters of the actuator 100.

[0052] like Figure 2 As shown, the actuator 100 of the present invention may include a housing 190 coupled to the casing 110 and serving as a shield.

[0053] Figure 3 and Figure 4 1 is a diagram showing the overall structure of an actuator 100 according to an embodiment of the present invention.

[0054] like Figure 3 As shown in FIG. 1 and FIG. 2 , the actuator 100 of the present invention is equivalent to a basic frame structure of the actuator 100 , including a housing 110 accommodating an internal structure, a first carrier 120 and a second carrier 130 .

[0055] The first carrier 120 carrying the first lenses 70a and 70b and the second carrier 130 carrying the second lenses 60a and 60b are equivalent to movers that move linearly along the optical axis direction (Z-axis direction) respectively. Correspondingly, from a relative perspective, the housing 110 is equivalent to a stator.

[0056] As described later, the first carrier 120 includes a first magnet M1, and the housing 110 includes a first coil unit C1. This first coil unit C1 faces the first magnet M1 and provides a driving force to the first magnet M1. As shown in the figure, the first coil unit C1 may include a plurality of coils C11, C12, C13, and C14.

[0057] When power of appropriate magnitude and direction is applied to the first coil portion C1 under the control of the first main driver D1 or the like, a driving force is generated between the first coil portion C1 and the first magnet M1 . This driving force causes the first carrier 120 to move forward and backward along the optical axis.

[0058] From a similar perspective, if the second main driver D2 or the like controls the second coil unit C2 (C21, C22) by applying power of appropriate magnitude and direction, the driving force generated between the second magnet M2 disposed on the second carrier 130 and the second coil unit C2 causes the second carrier 130 to move linearly along the optical axis. The second coil unit C2 may also be composed of one or more coils.

[0059] The drawings show a first carrier 120 carrying first lenses 70a and 70b and a second carrier 130 carrying second lenses 60a and 60b. However, this is merely an example, and it goes without saying that different numbers of lenses and carriers may be provided depending on the implementation.

[0060] In the following description, for the sake of efficiency, the number of carriers provided in the actuator 100 is illustrated as two. Figure 2 The carrier located at the bottom is referred to as the first carrier 120 , and the carrier located at the top is referred to as the second carrier 130 , with the optical axis direction of FIG. 1 being the reference, and the embodiments of the present invention will be described with the first carrier 120 as the center.

[0061] In this way, if the first carrier 120 and the second carrier 130 move linearly along the optical axis respectively, the lenses 60a, 60b, 70a, and 70b mounted on each carrier also move linearly along the optical axis, and the AF or zoom function is achieved through the relative position relationship of these lenses 60a, 60b, 70a, and 70b.

[0062] In order to prevent the magnetic force or electromagnetic force generated in the first coil portion C1 from leaking to the outside and to further concentrate it toward the first magnet M1 , a yoke plate (not shown) made of a metal material may be provided in the opposite direction to the first magnet M1 .

[0063] The first coil portion C1 of the present invention, which faces the first magnet M1 , includes n (n is a natural number greater than or equal to 2) coils. In the drawings, four (n=4) individual coils C11 , C12 , C13 , and C14 are shown as an example.

[0064] Balls B1 and B2 may be arranged between the first carrier 120 and the housing 110 and between the second carrier 130 and the housing 110 to enable the first carrier 120 and the second carrier 130 to move linearly more flexibly with minimized friction.

[0065] The first Hall sensor H1 is installed on the circuit substrate 170 together with the first coil portion C1 and the first main driver D1, and is equivalent to the following structure: using the Hall effect to sense the size and direction of the magnetic field (magnetic force) generated in the first magnet M1 in the relative direction, and outputting a corresponding signal.

[0066] As shown in the figure, the first magnet M1 provided on the first carrier 120 includes a variable portion CP having a different magnetic force magnitude in the optical axis direction (see Figure 9The first Hall sensor H1 facing the variable portion CP outputs a signal corresponding to the position of the first magnet M1. The variable portion CP and the related invention will be described in detail later.

[0067] Different from the prior art, the first driver for driving and controlling the movement of the first carrier 120 is divided into a first main driver D1 and a first sub-driver SD. There may be more than one first sub-driver SD, and the figure shows three first sub-drivers SD1, SD2, and SD3 as an example.

[0068] In this case, a single or minimized number of first Hall sensors H1 according to the present invention are communicably connected to the first main driver D1 .

[0069] The first Hall sensor H1 can of course be implemented as an independent electronic component or device, but can also be implemented as a single electronic component (chip) integrated with the first main driver D1 via a SOC (system on a chip) or the like. Therefore, in the drawings, the first Hall sensor H1 and the first main driver D1 are labeled with the same structure. The same applies to the second Hall sensor H2 and the second main driver D2.

[0070] The first main driver D1 of the present invention performs calculation processing on the output signal input from the first hall sensor H1 and controls the first coil portion C1 so as to apply electric power of a magnitude and direction according to the result.

[0071] Specifically, the first main driver D1 of the present invention may be configured to generate and output a command control signal for controlling the current applied to one or more coils among the n coils according to the output signal of the first hall sensor H1 .

[0072] When the first main driver D1 outputs a command control signal in this manner, the first sub-driver SD of the present invention controls the current applied to one or more of the plurality of coils C11, C12, C13, and C14 constituting the first coil unit C1 in accordance with the command control signal. Specific embodiments of the first main driver D1 and the first sub-driver SD will be described later.

[0073] Figure 5 is a diagram showing a detailed configuration for driving control of the first carrier 120, Figure 6 1 is a diagram illustrating an embodiment of the first magnet M1 , the first coil portion C1 , the first main driver D1 , and the first sub-driver SD.

[0074] Figure 5 and Figure 6The structures shown are structures related to the first driving unit for moving the first carrier 120 , and it goes without saying that these structures can also be applied to the driving portion of the second carrier 130 .

[0075] According to the embodiment, when the actuator 100 includes a plurality of carriers and a portion of the carriers is designed to have a larger stroke than the other portion of the carriers, Figure 5 and Figure 6 The structure shown can be applied to a carrier with a relatively long driving stroke, while a structure with a different form can be applied to a carrier with a relatively short driving stroke (see Figure 4 ), this goes without saying.

[0076] As shown in the figure, the first magnet M1 has a shape extending in the optical axis direction and includes a variable portion in which the magnitude of the magnetic force varies depending on the position in the optical axis direction by forming the thickness of the middle portion to be different.

[0077] The four (n=4) coils constituting the first coil unit C1 are arranged along the optical axis and in a direction opposite to the first magnet M1. The first coil unit C1 can be positioned on the left and right sides ( Figure 6 The reference) is grouped into a first group Ca and a second group Cb.

[0078] In order to improve the accuracy of linear movement and the efficiency of coil control, preferably, the plurality of coils C11 , C12 , C13 , and C14 are configured to provide driving force to the first magnet M1 in an alternating order of a first group Ca and a second group Cb.

[0079] Preferably, when the first carrier 120, ie the first magnet M1, is turned to the left ( Figure 6 When the control is performed in a manner that the coil C13 (second group) → the coil C11 (first group) → the coil C14 (second group) → the coil C12 (first group) in this order, current application is achieved.

[0080] If current of appropriate magnitude and direction is applied to the coils C11, C12, C13, and C14 constituting the first coil portion C1 through the control of the first main driver D1 and / or the first sub-driver SD, a corresponding driving force (magnetic force or electromagnetic force) is generated in the first magnet M1.

[0081] As described above, the first Hall sensor H1 should be set at a position opposite to the variable part CP of the first magnet M1. Therefore, when the first main driver D1 and the first Hall sensor H1 are implemented by a single chip, the first main driver D1 is also set at a position opposite to the variable part CP of the first magnet M1.

[0082] The first sub-driver SD of the present invention is communicatively connected to the first main driver D1 and controls the application of a current to its assigned coil in response to a command signal output from the first main driver D1. Therefore, in the implementation structure of the present invention, the first sub-driver SD can be limited in functionality, thereby offering the advantage of being fully implemented using a low-specification chip.

[0083] The drawings exemplarily show three first sub-drivers SD, which are mounted together with the first main driver D1 on the circuit substrate 170. To improve space utilization, the first sub-drivers SD can be placed in the space between the coils C11, C12, C13, and C14 constituting the first coil unit C1.

[0084] Figure 7 is a block diagram illustrating a detailed configuration of a first main driver 500 ( D1 ) and a first sub-driver 700 ( SD ) according to an embodiment of the present invention.

[0085] As illustrated in the figure, the first main driver 500 may include a first hall sensor 500 , an input unit 520 , an analysis unit 530 , a coil control unit 540 , a signal generation unit 550 , and a communication unit 560 .

[0086] The first main driver 500 according to the present invention can be implemented by various combined applications of electronic devices such as storage devices, processing devices, input / output devices, etc., components, etc. (ASIC, chipset, logic circuit, register, communication modem, MCU, etc.).

[0087] in this regard, Figure 1 The constituent elements of the first main drive 500 shown should be understood as functionally or logically distinct components, rather than physically distinct components.

[0088] That is, the various constituent elements shown in the above-mentioned drawings are equivalent to the logical structure used to effectively illustrate the technical ideas according to the present invention. Therefore, even if the various constituent elements are integrated or separated, as long as they can realize the functions performed by the logical structure of the present invention, they should be interpreted as being within the scope of the present invention. Moreover, if they are constituent elements that perform the same or similar functions, regardless of whether their names are consistent, they should be interpreted as being within the scope of the present invention. This is self-evident.

[0089] When explaining the logical structure, it goes without saying that the first main driver denoted by reference numeral 500 corresponds to the first main driver denoted by D1. The same applies to the first Hall sensor (H1, 510) and the first sub-driver (SD, 700).

[0090] When an output signal from the first Hall sensor 510 is input via the input unit 520, a component of the first main driver 500, the main processing unit 530 analyzes the output signal. Based on the analysis results, the signal generation unit 550 generates a command control signal containing information such as the target coil to which current is to be applied, and the magnitude and direction of the applied current.

[0091] The command control signal thus generated is output to one or more first sub-drivers SD through the communication unit 560, and if the command control signal is input through the second input unit 710 of the first sub-driver SD, the second coil control unit 720 of the first sub-driver SD controls the coils C11, C12, C13, and C14 for which it is responsible according to the command control signal input above.

[0092] According to an embodiment, the first main driver 500 may include a coil control part 540 that directly controls currents applied to m (m is a natural number greater than or equal to 1) coils among the n coils.

[0093] In this case, the signal generating unit 550 of the present invention can generate a command control signal for controlling the current applied to the nm coils, which are the m coils C1(1), ..., C1(m) directly controlled by the first main driver 500 (D1) excluding all the n coils (see Figure 7 ) coil.

[0094] If it is assumed that the total number of individual coils constituting the first coil portion C1 is six, the number of coils directly controlled by the first main driver D1 (m=2) is two, and the number of coils directly controlled by the first sub-driver SD is one, then in the case of being constructed as in an embodiment of the present invention, one first main driver D1 and four first sub-drivers SD are required.

[0095] A low-specification driver without a built-in Hall sensor, such as the first sub-driver SD of the present invention, and a driver with a minimum number of control channels even if a Hall sensor is built-in can be realized relatively easily.

[0096] Therefore, compared with designing and manufacturing a new single driver that controls six channels, when the main driver and sub-driver are constructed in a separate manner as in the present invention, not only the design freedom can be improved, but also the economy, convenience and efficiency of manufacturing and parts procurement can be improved.

[0097] Below, refer to Figure 8etc. describe in detail an embodiment of the present invention, namely, utilizing the relationship between the magnet of the present invention, whose magnetic force varies according to the position (optical axis direction reference), and the Hall sensor relative to the magnet, to accurately sense the position of the lens within an extended moving range (stroke) and utilize this to control the position of the lens.

[0098] The names and reference numerals of the components of the embodiments described below may be the same as those of the previously described embodiments (see Figures 1 to 7 ) have slightly different names or reference numerals. This is intended only to highlight the technical concepts of the embodiments described later. Therefore, it goes without saying that the constituent elements of the embodiments described below can represent corresponding constituent elements of the previously described embodiments based on corresponding relationships, inclusion relationships, and inclusion relationships at the technical concept or functional level.

[0099] Figure 8 is a diagram showing the structure of a magnet M1 according to a preferred embodiment of the present invention, Figure 9 FIG. 1 is a diagram illustrating the structural relationship between a magnet M1 and a Hall sensor H1 according to a preferred embodiment of the present invention.

[0100] The embodiment of the present invention described below is equivalent to the following embodiment: improving the magnetic properties of a magnet arranged in a direction opposite to the Hall sensor and used to sense the position of a lens, etc., so as to effectively achieve position sensing, etc. with only a single number or a minimum number of Hall sensors.

[0101] Therefore, the magnet M of the present invention described below may be a driving magnet that receives driving force from the coils C1 and C2 like the first magnet M1 or the second magnet M2 described above, or may be a sensing magnet that is provided on the carriers 120 and 130 independently of the driving magnet.

[0102] like Figure 8 As shown, the magnet M1 of the present invention can be formed so that its length extends along the optical axis (Z-axis direction), and the magnetic force (in gauss) on the surface facing the Hall sensor (H1 / D1) varies depending on the position (based on the optical axis). The magnet M1 of the present invention is mounted on a carrier, such as the first carrier 120 that carries the lens, and thus moves along the optical axis along with the lens and the carrier.

[0103] The actuator 100 of the present invention is configured such that when the magnet M1 moves along the optical axis, the position of the magnet M1 facing the Hall sensor H1 changes. As the opposing position changes, the signal value sensed and output by the Hall sensor H1 changes.

[0104] According to the implementation method, Figure 9As shown in FIG, a neutral zone (NZ) can be formed at the boundary between the magnetic poles (N pole and S pole) of the magnet M1. The neutral zone can also be formed by a physical structure such as injection molding as shown in the above-mentioned figures.

[0105] Specifically, the magnet M1 according to one embodiment of the present invention includes a variable portion CP. The magnetic force of the portion of the variable portion CP that faces the Hall sensor (H1 / D1) varies in magnitude depending on its position (referenced along the optical axis (Z-axis)). Specifically, the variable portion CP is configured so that the magnetic force varies in magnitude in a direction parallel to the optical axis.

[0106] like Figure 9 As shown, the variable part CP is divided into an N-pole part and an S-pole part based on the middle part. The N-pole part of the variable part CP and the S-pole part of the variable part CP can be constructed to have a greater magnetic force as they are farther away from the middle part of the variable part CP.

[0107] According to the implementation method, Figure 10 As shown, the magnet M of the present invention may be located in the middle portion of the variable portion CP and include a first portion FP1 having the same magnetic force magnitude.

[0108] Preferably, the above-mentioned first part FP1 is designed to have a magnetic force magnitude corresponding to the part with the smallest magnetic force magnitude in the variable part CP, and as described later, in order to apply a more precise linear function relationship in the relationship with the Hall sensor H1, it is preferably constructed in a form in which the N pole and the S pole are symmetrical to each other, as shown in the example in the figure.

[0109] Reference Figure 14 , the relationship between the conventional magnet m and the Hall sensor h is described below. Figure 14 1 is a diagram showing the relationship between a magnet m having alternating polarities but the same magnetic force and a Hall sensor h.

[0110] As shown in the figure, if the magnet m is in the position state of a1, the S pole with the same magnetic force is opposite to the Hall sensor h within a certain range, so the signal value A1 output by the Hall sensor h is as follows: Figure 14 As shown in the figure below, the value is constant, so the signal value of the Hall sensor h output in this part does not have the ability to resolve according to the position.

[0111] When the magnet m is in position a2, the influence of the N pole and the S pole is comprehensively reflected, so the signal value A2 output by the Hall sensor h changes with the position of the magnet m. Based on this, the output value of the Hall sensor h can determine the position of the magnet m.

[0112] If the movement continues and the magnet m becomes a position state such as a3, the Hall sensor h will leave the magnetic field range generated by the S pole and enter the magnetic field range generated by the N pole. Therefore, in this area, the signal value of the Hall sensor h outputs a constant signal value (substantial constant) corresponding to the maximum magnetic force value generated by the N pole. Therefore, the signal value of the Hall sensor h in this interval also has no resolution capability.

[0113] Therefore, the relationship between the position of the magnet m and the output value of the Hall sensor h forms an interval based on a one-to-one relationship of independent values, that is, the interval that can sense the position of the magnet m and realize position control based on this is limited to the predetermined section U where the magnetic pole boundary of the magnet m is relative to the Hall sensor h.

[0114] If the moving range of the lens is not large, position control can be performed only with the above-mentioned interval U that can distinguish the signal. However, when the moving range (stroke) of the lens is long, it is difficult to control the overall position using the above-mentioned structure. Therefore, in the past, a method of arranging multiple Hall sensors h along the optical axis and comprehensively using the signal system output from each Hall sensor h was applied.

[0115] On the contrary, in the case of the preferred embodiment of the present invention, as the magnet M1 moves with respect to the point forming the magnetic pole boundary, the position having different magnitudes of magnetic force faces the Hall sensor H1. Therefore, the position of the magnet M1 with respect to the optical axis and the corresponding independent output value HR of the Hall sensor H1 (see Figure 11 ) form a one-to-one correspondence, thereby expanding the interval LR that can perceive and control the position.

[0116] like Figure 10 As shown in the example, when the middle part of the variable part CP includes a first part FP1 having the same magnetic force magnitude, sudden changes in the point where the magnetic pole changes can be avoided, thereby enabling more stable signal processing. In addition, in order to more clearly maintain the linear characteristics of the output value of the Hall sensor H1, it is preferred that, as shown in the figure, the magnitude of the magnetic force of the above-mentioned first part FP1 corresponds to the minimum magnetic force of the N pole and / or the minimum magnetic force of the S pole.

[0117] In order to differentiate the magnetic force of the magnet M1 based on the optical axis, Figure 12 As shown in the aforementioned drawings, the variable portion CP may be configured such that the first thicknesses D1, D2, and D3, which are thicknesses in a direction perpendicular to the optical axis (Y axis based on the drawings), have different sizes.

[0118] When the variation of the first thickness is applied to differentiate the magnitude of the magnetic force at each position based on the optical axis, as shown in FIG. Figure 12As illustrated, the first portion FP1 may be designed to correspond to the smallest thickness in the variable portion CP.

[0119] When the variable portion CP is divided into an N-pole portion and an S-pole portion based on the middle portion, the N-pole portion and the S-pole portion may be configured such that the first thickness increases as the portion moves away from the middle portion of the variable portion. According to an embodiment, it is preferred that, as shown in FIG. Figure 8 As shown in FIG. 1 and FIG. 2 , the N-pole portion and / or the S-pole portion is configured so that the portion facing the Hall sensor h is formed as an inclined surface portion.

[0120] Furthermore, in order to further improve the accuracy of the signal system of the Hall sensor H1, it is preferable that the N-pole portion and the S-pole portion are configured to be symmetrical with respect to the middle portion of the variable portion CP.

[0121] In the case where the magnet M1 of the present invention is a driving magnet providing driving force in relation to the coil, the magnet M1 of the present invention may be arranged outside the variable portion CP and further include a second portion FP2 having the same magnetic force.

[0122] When the second part FP2 is provided outside the variable part CP as described above, the variable part CP located relatively inside may be arranged opposite to the Hall sensor H1, and the second part FP2 located relatively outside may be arranged opposite to the coil.

[0123] According to the embodiment of the present invention, the magnet M1 can have both a portion generating a sufficient driving force and a portion sensing an extended position in relation to the Hall sensor H1 in a separate manner, thereby achieving both enhanced driving force and accurate position sensing.

[0124] Figure 13 FIG is a diagram illustrating the structure of a magnet M1 according to another embodiment of the present invention. Figure 13 As shown in the figure above, by increasing the thickness in one direction relative to the optical axis (or decreasing relative to it), the magnetic force at each location facing the Hall sensor H1 can be differentiated. In this case, the portion corresponding to the area facing the Hall sensor H1 can also be configured as a single pole.

[0125] like Figure 13 As shown in the middle figure of FIG, the variable portion CP can also be implemented as a form in which the thickness is stepped toward the outside based on the magnetic pole boundary, as shown in FIG. Figure 13 As shown in the figure below, the thickness can be kept constant, but the magnetized area and the magnetized size can be applied in a variable manner, thereby making it possible to differentiate the magnitude of the magnetic force at each position relative to the Hall sensor H1.

[0126] Although the present invention has been described above through limited embodiments and drawings, the present invention is not limited thereto. It goes without saying that a person skilled in the art in the art to which the present invention belongs can make various modifications and variations within the scope of equivalence of the technical idea of ​​the present invention and the claims described below.

[0127] In the above description of the present invention, modifiers such as first, second, etc. are merely tool concepts used to relatively distinguish components from each other, and should be interpreted as not being used to indicate a specific order, priority, etc.

[0128] In order to emphasize or highlight the technical content of the present invention, the drawings attached to the description of the present invention and the illustrations of its embodiments may be shown in a slightly exaggerated form, but it should be interpreted as taking into account the aforementioned content and the matters shown in the drawings, etc., and it goes without saying that various forms of modified application examples can be performed at the level of ordinary technicians in this technical field.

Claims

1. A camera actuator, characterized in that: include: The carrier moves along the optical axis; a magnet disposed on the carrier and including a variable portion having a differentiated magnetic force magnitude in the optical axis direction; a plurality of coils, facing the magnet; a Hall sensor that is opposite to the variable portion and outputs a signal corresponding to the position of the magnet; a main driver, generating and outputting a command control signal, wherein the command control signal is used to control the current applied to one or more coils of the plurality of coils according to the output signal of the Hall sensor; as well as One or more sub-drivers control currents applied to one or more coils among the plurality of coils according to the command control signal.

2. The camera actuator according to claim 1, wherein: The main driver includes a coil control unit that controls current applied to one or more coils among the plurality of coils.

3. The camera actuator according to claim 1, wherein: The number of the plurality of coils is n, where n is a natural number greater than 2. The main driver comprises: an input portion, into which an output signal is input from the Hall sensor; A main processing unit, for analyzing the output signal; a coil control unit that controls currents applied to m coils among the plurality of coils, where m is a natural number greater than or equal to 1; a signal generating unit configured to generate a command control signal for controlling currents applied to nm coils among the n coils; and The communication unit outputs the command control signal to the sub-driver.

4. The camera actuator according to claim 1, wherein: The sub-driver includes: a second input portion to which the command control signal is input; and The second coil control unit controls current applied to one or more coils among the plurality of coils according to the command control signal.

5. The camera actuator according to claim 1, wherein: The magnet further includes a second portion disposed outside the variable portion and having the same magnitude of magnetic force.

6. The camera actuator according to claim 5, wherein: Two or more coils among the plurality of coils are configured to face the second portion.

7. The camera actuator according to claim 5, wherein: The plurality of coils are grouped into a first group and a second group based on the hall sensor, and the first group and the second group provide driving force to the magnet in an alternating order.

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