actuator assembly

Abstract

A shape memory alloy (SMA) actuator assembly includes: a support structure (211); a movable part (213) movable relative to the support structure; at least one SMA line (202) having a first portion and a second portion respectively attached to the support structure and the movable part, the SMA line being configured to drive movement of the movable part at least along a main axis upon contraction, the shortest side of the SMA actuator assembly extending along the main axis; an intermediate part (220) engaging the SMA line at a location between the first and second portions, the second portion of the SMA line being arranged at an angle to both the main axis and the first portion of the SMA line.

Description

[0001] field

[0002] This application relates to an actuator assembly, and more particularly to an actuator assembly comprising one or more shape memory alloy (SMA) wires.

[0003] background

[0004] WO 2011 / 104518A1 describes an actuator assembly that uses SMA lines to move a movable part supported on a support structure. For example, to provide optical image stabilization and / or autofocus (AF). In this example, eight SMA lines are arranged at an angle relative to the nominal principal axis (or optical axis), with a pair of SMA lines arranged on each of the four sides surrounding the principal axis. The SMA lines are connected such that, upon contraction, the two sets of four SMA lines provide a force with components in opposite directions along the principal axis, thereby achieving movement along the principal axis. The SMA lines in each set have two-fold rotational symmetry about the principal axis, thus the SMA lines are opposite each other to achieve lateral movement.

[0005] Overview

[0006] Current smartphone cameras tend to use larger diameter lenses to achieve better imaging performance. However, using larger and heavier lenses requires larger actuator components to accommodate the increased space occupied by the lenses. Furthermore, the increase in lens size necessitates increases in both motion travel and power output.

[0007] In existing actuator assemblies (e.g., WO 2011 / 104518A1), the height of the actuator typically increases with its footprint. This is because there exists a "minimum wire angle" that the actuator needs to prevent uncontrolled resonance of the SMA wire along the optical axis. Therefore, this design may be disadvantageous for supporting larger lenses, as the height (or thickness) of the actuator assembly is crucial in smartphone cameras.

[0008] In summary, this invention allows for the elimination of the interplay between the height of the actuator assembly and its footprint to accommodate larger lenses. Therefore, it allows mobile electronic devices to meet stringent height requirements. Furthermore, it provides greater flexibility to convert optical image stabilization (OIS) travel to autofocus (AF) travel within a given spatial envelope, and vice versa.

[0009] According to a first aspect of this embodiment, a shape memory alloy (SMA) actuator is provided, comprising:

[0010] Support structure;

[0011] A movable component that is movable relative to the supporting structure;

[0012] At least one SMA line having a first portion and a second portion respectively attached to a support structure and a movable member, the SMA line being configured to drive movement of the movable member at least along a main axis upon retraction, the shortest side of the SMA actuator assembly extending along the main axis; an intermediate member engaging the SMA line at a location between the first and second portions, the second portion of the SMA line being arranged at an angle to both the main axis and the first portion of the SMA line.

[0013] The SMA actuator can be a micro-actuator for a camera assembly or a mobile phone. The movable part may include a lens having an optical axis along a longitudinal axis, wherein the SMA actuator provides one or more of the following for the camera assembly: optical image stabilization (OIS), autofocus (AF), and zoom.

[0014] SMA actuator assemblies may include one or more (e.g., elongated) SMA lines, which may be directly connected to or connected via a flexure to a movable part (e.g., a lens holder). In the latter case, motion caused by the contraction of the SMA lines can be transmitted via the flexure.

[0015] The term "shape memory alloy (SMA) wire" can refer to any element containing SMA. SMA wire can have any shape suitable for the purposes described herein. SMA wire can be elongated and can have a circular cross-section or any other cross-section shape. The cross-section can vary along the length of the SMA wire. It is also possible that the length of the SMA wire (as defined, however it may be) can be similar to one or more of its other dimensions. SMA wire can be flexible, or in other words, SMA wire can be pliable. In some examples, when connected in a straight line between two elements, the SMA wire can only exert tension to force the two elements together. In other examples, the SMA wire can bend around the element, and the SMA wire can exert a force on the element as it tends to straighten under tension. SMA wire can be beam-like or rigid and is capable of applying different forces (e.g., non-tension) to the element. SMA wire may or may not include non-SMA materials and / or components. For example, SMA wire may include a core of SMA and a coating of non-SMA materials. Unless the context otherwise requires, the term "SMA line" can refer to any configuration of an SMA line that acts as a single actuating element, such that the single actuating element can be independently controlled to generate a force acting on the element. For example, an SMA line may comprise two or more sections of an SMA line arranged mechanically in parallel and / or in series. In some arrangements, an SMA line may be part of a larger segment of SMA line. This larger segment of SMA line may comprise two or more sections that can be individually controlled, thereby forming two or more SMA lines.

[0016] SMA wires can be formed from any suitable shape memory alloy material (typically, nickel-titanium alloys, such as nitinol), but these SMA wires may also contain a third component (such as copper). SMA wires can have any cross-sectional profile and diameter suitable for the application. For example, SMA wires can all have a cross-sectional diameter of 25µm, 30µm, or 35µm, capable of generating a maximum force between 120mN and 400mN while keeping the strain in the SMA wire within safe limits (e.g., a length reduced by 2%-3% from the original length). Increasing the diameter of each SMA wire from 25µm to 35µm approximately doubles the cross-sectional area of ​​the SMA wire, and thus approximately doubles the force provided by each SMA wire.

[0017] The first and second portions of the SMA wire are respectively attached to the support structure and the movable part, wherein such attachment can be achieved by any suitable means known to those skilled in the art, such as by welding, bonding and crimping.

[0018] The shortest side of the SMA actuator assembly extends along the main axis. More specifically, the SMA actuator assembly may include three axes, and the main axis may be defined along the smallest dimension of the SMA actuator assembly. Therefore, the SMA actuator assembly can be thinnest along the main axis.

[0019] The second portion of the SMA line can be arranged at an angle to both the principal axis and the first portion of the SMA line. That is, the second portion of the SMA line can be arranged neither parallel to the first portion of the SMA line and the principal axis, nor perpendicular to the first portion of the SMA line and the principal axis.

[0020] The intermediate component is configured to engage or support the SMA line at a position between the first and second parts. Therefore, an angle is formed between the two parts through the support provided by the intermediate component.

[0021] The SMA line is configured to drive movement of the movable part at least along the main axis during contraction. However, the SMA line can also be configured to drive movement of the movable part in other directions, such as in a direction perpendicular to the main axis.

[0022] At least one SMA line may comprise a pair of SMA lines, four SMA lines arranged individually or in pairs, or eight SMA lines arranged individually or in groups of four. Preferably, the multiple SMA lines are evenly distributed around the four sides of the movable member. Preferably, the SMA lines are arranged symmetrically in two or four directions around the optical axis. Optionally, the SMA lines are configured to drive additional movement of the movable member in a direction perpendicular to the main axis during retraction. Thus, when eight SMA lines are used in an SMA actuator assembly (similar to the actuator assembly disclosed in WO 2011 / 104518A1), the eight SMA lines together are configured to guide movement of the movable member in any direction.

[0023] Optionally, the second portion extends relative to the main axis at a smaller angle than the first portion relative to the main axis. Advantageously, such an arrangement allows the second portion of the SMA line attached to the movable part to be arranged at an angle greater than a “minimum line angle” sufficient to prevent uncontrolled resonance along the optical axis, regardless of the actuator size. This “minimum line angle” can be at least 8 degrees or at least 10 degrees relative to the main axis or relative to an axis perpendicular to the main axis. More specifically, while increasing the actuator’s footprint, the increase in the length of the SMA line extends only the laterally extending (or slightly inclined) first portion. Even if the total length of the SMA line is extended, the second portion can be maintained at the same angle as known actuators such as those disclosed in WO2011 / 104518A1, or at a sharper angle than known actuators.

[0024] Optionally, the second portion extends along the main axis to a greater extent than the first portion extends along the main axis. Therefore, advantageously, extending the first portion of the SMA line can be done without significantly increasing the height of the actuator.

[0025] Optionally, the length of the first part is longer than the length of the second part. Therefore, advantageously, the length of the SMA line can be independent of the height of the actuator.

[0026] Optionally, the first portion extends substantially perpendicular to the main axis or at an acute angle relative to the main axis. For example, when a pair of opposing SMA lines are provided to drive a movable part in opposite directions, their respective first portions can extend parallel to each other. Thus, advantageously, when viewed from a direction perpendicular to the main axis, this arrangement prevents the SMA lines from intersecting each other, thereby reducing the risk of contact or friction between the SMA lines.

[0027] Optionally, the intermediate component extends from the support structure. For example, the intermediate component may be a post protruding from the base of the actuator assembly and extending along the main axis. More specifically, the intermediate component defines the boundary between the first and second portions, thereby causing misalignment between the first and second portions. In embodiments with multiple SMA lines, an intermediate component may be provided for each of the SMA lines, or a single intermediate component may be provided for all SMA lines.

[0028] Optionally, the intermediate component includes end stops for defining the range of motion of the movable component in a direction perpendicular to the main axis. For example, when the intermediate component extends from the support structure, it can additionally serve as an end stop defining the range of motion of the movable component. Advantageously, such an arrangement may eliminate the need for additional components to form the intermediate component, as the end stops used may still be present in the actuator.

[0029] Optionally, the SMA line is slidably supported on a support member, or alternatively, optionally supported by rollers. More specifically, the support member may include rollers or hooks for supporting the SMA line. For example, the SMA line can slide along its length on the rollers or hooks, thereby correspondingly changing the respective lengths (or ratios) of the first and second portions. Advantageously, such an arrangement can reduce friction between the SMA line and the support structure.

[0030] Optionally, the support member includes a flexure for supporting the SMA line, wherein the plane in which the flexure extends along the SMA line is compliant. For example, the SMA line may be fixedly attached to an end of the flexure. During contraction, the end of the flexure may pivot about a fixed point of the flexure at the support structure. Advantageously, once the unenergized SMA line has cooled down, the flexure allows the movable component to return to its default position.

[0031] Alternatively, the contraction of the SMA line is substantially less than the displacement of the movable part. For example, a flexural element can amplify the movement (or stroke) of the movable part given a given length of the SMA line.

[0032] Optionally, the flexure extends at a non-zero angle relative to a first portion of the SMA line, wherein the angle determines the achievable displacement of the SMA line. For example, a smaller angle between the first portion of the SMA line and the flexure can result in a larger displacement of the movable part, which is particularly useful in zoom applications. The adjustment can be performed manually, controlled by a controller, or set during manufacturing to suit the type of camera to which the actuator will be mounted.

[0033] According to a second aspect of the present invention, a shape memory alloy (SMA) actuator assembly is provided, comprising:

[0034] A first component and a second component, the first component and the second component being movable relative to each other; and

[0035] One or more actuation units, each actuation unit comprising:

[0036] - A force adjustment mechanism, which is connected to the first component;

[0037] - A connecting link, which connects the force adjustment mechanism and the second component; and

[0038] - An SMA line, which is connected between the first component and the force adjustment mechanism, is used to apply an input force to the force adjustment mechanism, thereby causing the force adjustment mechanism to apply an output force to the connecting link, and causing the connecting link to apply an actuating force to the second component, wherein the connecting link is compliant in the direction perpendicular to the direction of the actuating force; and

[0039] One or more actuation units are arranged (or the SMA lines are arranged) to drive the second component relative to the first component at least along the main axis, the shortest side of the SMA actuator assembly extending along the main axis.

[0040] Preferably, the first component includes a support structure, and the second component includes a movable component. The force adjustment mechanism can be implemented by a flexure device, wherein the connecting rod can be implemented by a flexure arm.

[0041] Optionally, the SMA line is arranged at a non-zero angle to the main axis.

[0042] Compared to the embodiment of the first aspect of the invention, the second portion of the SMA line can be replaced by a force adjustment mechanism according to the second aspect. Advantageously, by allowing the SMA line to extend in a direction substantially perpendicular to the main axis or to tilt at least at a shallower angle compared to known actuator assemblies, the use of the force adjustment mechanism ensures that the length of the SMA line and the total height of the actuator assembly are mutually independent.

[0043] Optionally, the force adjustment mechanism is configured such that, in response to a change in the length of the SMA line, the end of the SMA line connected to the force adjustment mechanism moves a first distance relative to the first component, and the end of the connecting link connected to the force adjustment mechanism moves a second distance relative to the first component, the second distance being greater than the first distance. More generally, this second distance is greater than the change in the length of the SMA line. This arrangement can be used to amplify the achievable stroke of the SMA actuator assembly.

[0044] Alternatively, the force adjustment mechanism is configured such that, in response to a change in the length of the SMA line, the end of the SMA line connected to the force adjustment mechanism moves a first distance relative to the first component, and the end of the connecting rod connected to the force adjustment mechanism moves a second distance relative to the first component, the second distance being less than the first distance. More generally, the second distance is less than the change in the length of the SMA line. For example, such an arrangement can be configured to increase the applicable actuation force given an input force by the SMA line.

[0045] In a broader sense, in some embodiments, the second aspect uses a force adjustment mechanism as a lever to amplify or at least adjust the displacement of the second component achievable by a given amount of SMA line contraction. Additionally, or alternatively, by rotating at least a portion of the force adjustment mechanism, this embodiment can reduce the length of the SMA line required to achieve the desired stroke. Therefore, such an arrangement can provide a more compact and energy-efficient SMA actuator assembly.

[0046] In some embodiments, the connecting link can be considered as the component primarily responsible for transmitting actuation force to the second component. The connecting link can be implemented by any element or device capable of performing the dual function of transmitting actuation force to the second component and providing compliance in a direction perpendicular to the actuation force direction.

[0047] Optionally, the connecting link is a flexure or includes a flexure. The flexure may be elongated and may be rigid along its length and compliant in a direction perpendicular to its length. That is, the connecting link may be referred to as a flexure arm, which is configured to be easily bent in the plane of motion, particularly in the direction orthogonal to the actuating force, but may be rigid or non-compliant in other directions.

[0048] In some embodiments, in at least one actuation unit, the SMA line may be connected to a first component at or near a corner of the actuator assembly, and to a force adjustment mechanism at or near an adjacent corner of the actuator assembly.

[0049] In some embodiments, in at least one actuation unit, the connecting rod may include at least one bend. The bend may be a hairpin bend, such as a 180° hairpin bend.

[0050] In some embodiments, in at least one actuation unit, the force adjustment mechanism can be configured such that when the SMA line is in a tensioned state, the connecting link is in a compressed state.

[0051] Alternatively, the connecting link can be configured to apply a lateral biasing force to the second component to return the second component to a default (or centered) position and / or to hold the second component in a default (or centered) position. This can be particularly achieved in embodiments where the connecting link includes a flexure.

[0052] Optionally, the connecting link can restrict movement of the second component in a direction perpendicular to the actuation direction. For example, in embodiments where the first or second component includes a lens or image sensor, the connecting link can restrict movement along or parallel to the optical axis. Regarding the image sensor, the optical axis can be considered as an axis perpendicular to the photosensitive surface of the image sensor. The connecting link can be a pre-formed flexible arm that restricts movement in a direction perpendicular to the main axis.

[0053] Alternatively, the connecting link can be a rigid member, such as a rod, with a pin joint that allows the connecting link to pivot in the plane of motion. For example, the pivot can be a post extending from the force adjustment mechanism and hingedly attached to one of the first and second components (particularly the first component). Advantageously, such an arrangement allows for precise control of the displacement of the second component. In some other embodiments, the pivot can be a post extending from or in contact with the force adjustment mechanism, and the force adjustment mechanism can be configured to roll on the surface of the post when the SMA line is energized. In such embodiments, the pivot forms part of a type 1 lever system to increase the displacement of the second component.

[0054] Alternatively, the connecting link may include a rolling support, such as a roller support or a ball support. The rolling support may include rolling elements, such as rollers or balls, supported on respective support surfaces of the movable part and the force adjustment mechanism. The rolling support thus connects the movable part and the force adjustment mechanism and is arranged to apply an actuating force to the movable part via the rolling elements. The rolling support achieves compliance in a direction perpendicular to the actuating force by allowing the rolling elements to roll perpendicular to the actuating force. The support surfaces may be arranged orthogonally to the actuating force.

[0055] Alternatively, the connecting rod may include a plain bearing. A plain bearing can also be referred to as a sliding bearing. The plain bearing includes a support surface on the movable part and a complementary support surface on the force adjustment mechanism, wherein the two support surfaces are slidable relative to each other. Thus, the plain bearing connects the movable part and the force adjustment mechanism by including complementary surfaces on these parts and is arranged to apply an actuating force to the movable part via the support surfaces. The plain bearing achieves compliance in a direction perpendicular to the actuating force by allowing relative sliding of the support surfaces. The support surfaces may be arranged orthogonally to the actuating force. The plain bearing may include a friction-reducing material, such as a liquid or solid lubricant, between the support surfaces.

[0056] During operation, the connecting rod can typically be in a tensioned state. A force adjustment mechanism can pull the movable component via the connecting rod to apply an actuating force to the movable component. This is particularly preferred, for example, when the connecting rod includes a flexural element. The end of the connecting rod connected to the second component can be fixed relative to the second component. The actuating force can be substantially in the same direction as the output force.

[0057] Alternatively, the connecting rod can typically be in a compressed state. A force adjustment mechanism can actuate the movable part via the connecting rod to apply an actuating force to the movable part. This is particularly preferred, for example, when the connecting rod includes a rolling support or a sliding support.

[0058] Optionally, the force adjustment mechanism includes:

[0059] The movable part, the SMA cable, and the connecting rod are connected to the movable part; and

[0060] A force-adjusting flexure is connected between the movable part and the first component and is configured to bend in response to an input force.

[0061] The movable part can be referred to as the flexural body.

[0062] Alternatively, for example, in embodiments where the force adjustment mechanism and the connecting rod include a flexure, at least one of the connecting rod and the force adjustment flexure is configured to have lower stiffness in the direction along the main axis than in any other direction to facilitate movement of the movable portion.

[0063] Alternatively, for example, in an embodiment where the force adjustment mechanism includes a flexure, the force adjustment flexure is elongated and rigid along its length, and compliant in a direction perpendicular to its length.

[0064] Optionally, two or all of the movable portion, connecting rod, and force-adjusting flexure can be formed separately. In embodiments, the force-adjusting flexure can be formed of the same or different material as the connecting rod and / or the force-adjusting flexure. For example, the movable portion can be rigid, or at least have a higher stiffness than the connecting rod and / or the force-adjusting flexure. In embodiments, the movable portion can be attached to the connecting rod and / or the force-adjusting flexure by any suitable attachment method (e.g., welding, adhesives, and mechanical means). Alternatively, the movable portion can be integrally formed with the force-adjusting flexure and / or the connecting rod. Advantageously, such an arrangement can lead to a more efficient manufacturing process and lower production costs.

[0065] Optionally, at least one SMA line includes a first SMA line and a second SMA line, which are configured to drive the movement of the movable part or the second part in a first direction and a second direction opposite to the first direction, respectively.

[0066] Optionally, at least one SMA line comprises four pairs of SMA lines, wherein the four pairs of SMA lines are arranged around the principal axis with double symmetry (e.g., double rotational symmetry).

[0067] Optionally, the movable component or the second component includes one or more lenses. The main axis can be the optical axis of one or more lenses. For example, when one or more lenses are supported on the movable component or the second component, the one or more lenses can move relative to the image sensor on the support structure or the first component.

[0068] Optionally, the movable component or second component includes an image sensor. The main axis may be an axis perpendicular to the photosensitive area of ​​the image sensor. The image sensor may be movable relative to one or more lenses supported on another movable component or second component, or on a support structure or first component.

[0069] The features of the first aspect of the invention can be combined with any features of the second aspect. Brief description of the attached diagram

[0071] Some embodiments of the invention will now be described by way of example only with reference to the accompanying drawings, in which:

[0072] Figure 1 This is an exploded view of the SMA actuator line device located in the camera;

[0073] Figure 2 This is a side view of an SMA actuator according to a first embodiment of the present invention;

[0074] Figure 3A and Figure 3B These are corresponding side views and plan views of the SMA actuator according to the second embodiment of the present invention;

[0075] Figure 4A and Figure 4B This is a side view of a different confirmed SMA actuator line arrangement according to a third embodiment of the present invention;

[0076] Figure 5 This is a side view of an SMA actuator according to a fourth embodiment of the present invention;

[0077] Figure 6 This is a side view of an SMA actuator according to a fifth embodiment of the present invention;

[0078] Figure 7 This is a side view of an SMA actuator according to a sixth embodiment of the present invention;

[0079] Figure 8 This is a side view of an SMA actuator according to a seventh embodiment of the present invention;

[0080] Figure 9A and Figure 9B These are side views of the SMA actuators according to the eighth and ninth embodiments of the present invention, respectively.

[0081] Figure 10 This is a side view of an SMA actuator according to a tenth embodiment of the present invention;

[0082] Figure 11 This is a side view of an SMA actuator according to the eleventh embodiment of the present invention; and

[0083] Figure 12 This is a side view of the SMA actuator according to the twelfth embodiment of the present invention.

[0084] Detailed description

[0085] Figure 1An exploded view of a known shape memory alloy (SMA) actuator wire device 10 in a miniature camera is shown. The SMA actuator device 10 includes a static component 5 comprising a support structure 11 and a screening can 12 attached to the support structure 11. The support structure 11 is an integral base and sensor holder for mounting an image sensor. The SMA actuator device 10 also includes a movable component 6, which is a camera lens assembly including a lens holder 13 that carries at least one lens (not shown).

[0086] In some other embodiments, the support structure 11 may include a camera lens assembly including a lens holder 13 that carries at least one lens (not shown), wherein the movable part 13 may include a sensor holder for mounting an image sensor. That is, in these alternative embodiments, the image sensor is movable relative to the (fixed or movable) lens.

[0087] In this example, actuator 10 includes eight SMA lines 2, each attached between a static member 5 and a moving member 6. When viewed along the optical axis, in a first direction, a pair of intersecting SMA lines 2 are provided on each of the four sides of the SMA actuator device 10. The SMA lines 2 are attached to the static member 5 and the moving member 6 in a configuration such that the SMA lines 2 contract upon heating and thus provide the moving member 6 with relative motion having multiple degrees of freedom, thereby providing both autofocus (AF) and optical image stabilization (OIS).

[0088] Therefore, for each pair of SMA wires 2, one end of the SMA wire 2 is attached to two static mounting portions 15, which are themselves mounted to the static component 5 for attaching the SMA wire 2 to the static component 5. The static mounting portions 15 are adjacent to each other but separate to allow them to be at different potentials.

[0089] Similarly, for each pair of SMA wires 2, one end of the SMA wire 2 is attached to a movable mounting portion 16, which is itself mounted to the movable component 6 for attaching the SMA wire 2 to the movable component 6. The movable component 6 also includes a conductive ring 17 connected to each movable mounting portion 16 for electrically connecting the SMA wires 2 together at the movable component 6.

[0090] The static mounting portion 15 and the movable mounting portion 16 include a crimping tab 23, which can form a crimp and is used to hold the SMA wire 2. The movable mounting portion 16 may include an electrical connection tab 31 for providing an electrical connection with the conductive ring 17. Therefore, in Figure 1In the example shown, the crimping tab 23 forming the crimp portion is an integral part of the static and moving portions of the actuator device 10. A method for forming the crimp portion and capturing the SMA line within the crimping tab 23 is described in International Patent Publication No. WO2016 / 189314.

[0091] SMA lines 2 are connected such that during contraction, the two sets of four SMA lines 2 provide forces with components in opposite directions along the main axis, thereby enabling movement along the main axis. Each set of SMA lines has double rotational symmetry about the main axis, such that the SMA lines are opposite each other to achieve lateral movement.

[0092] like Figure 1 As shown, a pair of SMA lines 2 are arranged on each of the four sides surrounding the optical axis, and these pairs of SMA lines 2 extend at an angle to the optical axis. There exists a "minimum wire angle" that the actuator requires to prevent uncontrolled resonance of the SMA lines 2 along the optical axis. Therefore, to maintain this wire arrangement and prevent the uncontrolled resonance, the height of the actuator is typically increased during the expansion phase. Thus, if the height (or thickness) of the actuator assembly is critical, this known design may be disadvantageous for larger lenses.

[0093] In practice, when SMA line 2 is not energized, i.e., when SMA actuator 10 is de-energized and the SMA line has been sufficiently cooled, SMA line 2 is no longer under tension. Therefore, in most cases, a certain degree of slack can be observed on the unenergized SMA line 2. This can lead to free movement of the SMA line and the lens bracket. Since SMA lines 2 are crossed when viewed from the side, this free movement can cause the SMA lines to come into contact with and rub against each other, resulting in large-area wear of the lines.

[0094] This invention provides various means for eliminating the interaction between the footprint and height of an actuator. In some embodiments, the invention can reduce or eliminate wire wear. The means can be applied together or individually, and can be applied to any SMA actuator device with inclined SMA wires.

[0095] Figure 2 An SMA actuator 210 according to a first embodiment of the present invention is shown. Viewed from the side of the actuator 210, a pair of SMA lines 202 connecting the movable member 213 and the base 211 are provided. For ease of comparison, dashed lines are also shown in the figure. Figure 1 The SMA line 2 used in the known embodiments.

[0096] exist Figure 2The diagram shows a pair of SMA lines 202 supported or at least interfered with by corresponding rollers 222. Rollers 222 are mounted on a support member 220, which extends from a support structure 211 along the optical axis O. Rollers 222 are freely rotatable relative to the support member 220. Therefore, when the SMA lines 202 slide relative to the support member 220, the rollers 222 reduce friction and wear on the SMA lines 202.

[0097] In some embodiments, the rollers may be replaced by non-rotatable supports. That is, in these embodiments, the SMA lines may slide directly on the contact surfaces of their respective non-rotatable supports (e.g., hooks). To reduce friction and wear, the contact surfaces may be provided with sacrificial coatings and / or friction-reducing devices, such as polymer coatings, polished surfaces, lubricants, or any other suitable friction-reducing devices.

[0098] The support member 220 can be an additional component attached to the surface of the support structure 211 by known methods, such as adhesive or mechanical connection devices. Preferably, as Figure 2 As shown, the support member 220 is integrally formed with the support structure 211. Advantageously, this arrangement reduces the complexity of the manufacturing process and improves the robustness of the support member 220.

[0099] The support member 220 may also serve as a lateral end stop for the movable member 213. More specifically, the support member 220 defines the limit point of lateral movement of the movable member 213. For example, once the movable member reaches this limit point, the support member 220 abuts against the side surface of the movable member 213 and thus stops further movement in the direction of movement. To reduce noise and suppress sudden changes in movement, the side surfaces of the movable member 213 and / or the side surfaces of the support member 220 may be provided with suitable damping materials, such as an elastomer layer, foam, damping gel, or any other suitable damping material.

[0100] In the depicted embodiment, roller 222 is positioned at substantially the same level as its corresponding crimp 223 on support structure 211. Therefore, the first portion 202a of the SMA line extends in a direction substantially perpendicular to the optical axis. However, in some other embodiments, rollers may be positioned along the optical axis at locations different from their corresponding crimps, and thus the SMA line may be tilted relative to the optical axis.

[0101] Because the SMA line 202 is supported or interfered with by the roller 222, the second portion 202b of the SMA line is arranged at an angle to the corresponding first portion 202a. Therefore, the second portion 202b of the SMA line is at least tilted relative to the optical axis O. Compared to the prior art SMA line 2 shown by the dashed line, the second portion 202b of the line extends at a sharper angle relative to the optical axis O. Therefore, advantageously, this arrangement is less prone to uncontrolled resonance on the SMA line 202 than those characterized in known arrangements.

[0102] Therefore, the mutual influence between the length of the SMA line 202 and the height of the SMA actuator 210 is advantageously eliminated. For example, when enlarging the SMA actuator 210, such as to accommodate larger and / or heavier lenses, only the first portion 202a of the SMA line is lengthened (e.g., by increasing the spacing between the rollers 222 and their corresponding pressing portions 223), while maintaining the length and line angle of the second portion 202b of the SMA line, without needing to increase the height of the SMA actuator.

[0103] In addition, such as Figure 2 The arrangement shown allows the first portions of the SMA lines 202 to extend substantially parallel to each other. That is, when viewed from the side of the actuator, the first portions 202a of the SMA lines do not cross each other. More specifically, the longer, more relaxed portions of the SMA lines 202 do not cross each other. Advantageously, this embodiment reduces the risk of wear damage and the risk of short circuits between adjacent SMA lines 202 when they are not energized.

[0104] In other embodiments, when viewed from the side of the SMA actuator, the first portions of the SMA lines 202 may not extend parallel to each other, and may extend at an angle and / or intersect each other. For example, the roller 222 may not be at the same level as the corresponding crimping portion 223 of the SMA lines, and therefore the first portions of the SMA lines may be slightly inclined. Due to the angled arrangement of the lines in the first portions of the SMA lines, such embodiments can have a slightly reduced actuator footprint.

[0105] SMA actuator 210 (and other SMA actuators according to the invention) includes eight SMA lines 202, which are oriented and function similarly to SMA actuator 10. For example, the eight SMA lines 202 drive the movable member 213 to move in all directions. That is, the SMA lines 202 can move the movable member together in a direction along the main axis, or in a direction perpendicular to the main axis, or in any other direction.

[0106] The force applied to the movable part by eight SMA lines (or, in the embodiments discussed further below, eight actuation units) can be equivalent to the force applied by the coupling. Figure 1 The existing technology actuator describes the orientation or arrangement of eight SMA lines.

[0107] More specifically, the forces (e.g., when visualized as vectors at specific locations in space) are arranged on each of the four sides (i.e., the first, second, third, and then fourth sides) surrounding the main axis. When viewed perpendicularly from the main axis, the two forces on each side are inclined in opposite directions relative to each other. The four sides with the forces arranged extend in a loop around the main axis. In this example, the sides are vertical and thus form a square (when viewed along the main axis), but alternatively, the sides can take different shapes, such as quadrilaterals. In this example, the forces are parallel to the outer surface of the square envelope of the movable part 213, but this is not required.

[0108] Four forces (including one force on each side) form a “first” group with a component in one direction (“upward”), and the other four forces form a “second” group with a component in the opposite direction (“downward”). In this text, “upward” and “downward” generally refer to opposite directions along the principal axis.

[0109] These forces are arranged symmetrically, with the same magnitude and tilt angle, such that the first and second groups of forces are each arranged with double rotational symmetry about the principal axis.

[0110] As a result of this symmetrical arrangement, different combinations of forces can drive the movement of the movable part 213 in multiple degrees of freedom, as shown below.

[0111] When the first set of forces is generated together, it drives upward motion, and when the second set of forces is generated together, it drives downward motion.

[0112] In each pair, adjacent force pairs (when generated differently) drive tilting about a transverse axis perpendicular to the principal axis z. Tilting in any direction can be achieved as a linear combination of tilts about the two transverse axes.

[0113] A set of four forces (including two forces from each group) when generated together drive motion along a transverse axis perpendicular to the principal axis z. Motion in any direction perpendicular to the principal axis z can be realized as a linear combination of motions along the two transverse axes.

[0114] SMA actuators can have other specific arrangements.

[0115] Control circuitry can be electrically connected to the SMA line to provide drive current to drive these movements, as described, for example, in WO 2011 / 104518 A1 (WO 2011 / 104518 A1 is incorporated herein by reference to the fullest extent permitted by law).

[0116] Figure 3A and Figure 3B Side and plan views of an SMA actuator 310 according to a second embodiment of the present invention are shown respectively. As viewed from the side of the actuator 310, a pair of SMA lines 302 are provided connecting the movable member 313 and the base 311. As viewed from the plan view of the SMA actuator 310, there are four pairs of SMA lines 302, each pair of SMA lines 302 being provided on a corresponding side of the SMA actuator 310, wherein the SMA lines 302 on opposite sides of the SMA actuator 310 can drive the movable member 313 to move in opposite directions when contracted.

[0117] exist Figure 3A The image shows a pair of SMA lines 302 supported or at least interfered with by a flexure 322. In this embodiment, when viewed from the side, the SMA lines 302 in each pair intersect each other, which reduces the space occupied by the actuator. However, in other embodiments, some or all of the SMA lines in each pair 302 may be arranged in a manner similar to... Figure 2 The arrangement shown is parallel to each other and extends substantially in a direction perpendicular to the optical axis.

[0118] The SMA wire 302 is securely attached to the contact surface of the flexure 322 by any suitable means, such as by adhesion or by mechanical means. Furthermore, the tension in the SMA wire 302 compresses the flexure 322 toward their anchor points, which in turn helps to hold the SMA wire 302 on the contact surface.

[0119] The flexural member 322 includes a flexural arm 322a, which is fixed to a support member 320 at a corresponding fixing point 322b. The support member 320 extends from the support structure 311 along the optical axis O. Similar to... Figure 1 In the first embodiment, the support member 320 serves as an end stop for the movable member 313 and defines the limit point of lateral movement.

[0120] The flexure 322 is compliant only in a plane (e.g., the XZ or YZ plane) in which the SMA line 302 extends parallel to the optical axis O, and is non-compliant in any other direction. Therefore, during contraction, the force from the SMA line 302 can compress the flexure 322 and cause the flexure arm 322a to deform or bend towards the support member 320. That is, the ends of the flexure 322 rotate about their respective fixed points 322b. Advantageously, when the SMA line 302 is not energized, the flexure arm 322a can bias the ends of the respective flexure 322 towards their default positions to minimize slack in the SMA line 302. In other words, the biasing force from the flexure 322 always maintains tension in the SMA line 302.

[0121] In the default position, for example when the SMA line 302 is not energized, the flexure arm 322a extends substantially along the optical axis, and the first portion 302a and the second portion 302b of the SMA line extend at angles α and β, respectively, relative to their respective flexure arms 322a. Since the first portion 302a of the SMA line in this embodiment is inclined with a steeper gradient compared to the second portion 302b of the SMA line, the angle α is greater than β.

[0122] The support member 320 can be an additional component attached to the surface of the support structure 311 by known methods, such as adhesives or mechanical fasteners. Preferably, as Figure 3A As shown, the support member 320 is integrally formed with the support structure 311 and serves as an end stop for restricting the lateral movement of the movable member 313.

[0123] In some other embodiments, the SMA actuator 310 may include a flexure having a corresponding flexure arm directly attached to the support structure 311. That is, in these embodiments, the support member 320 may be absent, even though end stops may be provided to limit the lateral movement of the movable member 313. Advantageously, such an arrangement allows for a longer flexure arm, making it more suitable for actuators requiring larger displacements (e.g., strokes) of the movable member.

[0124] Figure 4A A side view of the wiring arrangement in an SMA actuator 410 according to a third embodiment of the present invention is shown. The SMA actuator 410 is structurally and functionally similar to... Figure 3A The SMA actuator 310. For example, the SMA line 402 is supported by and fixedly attached to the end of the flexure 422, a first portion 402a is attached to the support structure 411, and a second portion 402b is attached to the movable member 413. Although Figure 4A Only a single SMA line 402 and some key components are shown, but other components (such as the second SMA line) are still present.

[0125] The SMA actuator 410 differs from the second embodiment 310 in that the flexure 422 extends at an angle to the optical axis. This arrangement allows the movement or stroke of the movable component 413 to be amplified. The degree of amplification depends on the relative orientation between the flexure 422 and the corresponding first portion 402a of the SMA line (e.g., the portion connected to the support structure).

[0126] by Figure 4A For example, the flexure 422 is angled away from the optical axis in the direction toward the movable member 413. Therefore, the angle α between the flexure 422 and the first portion 402a of the SMA line is an acute angle, and is sharper than the obtuse angle β between the flexure 422 and the second portion 402b of the SMA line.

[0127] During contraction, the first portion 402a of the SMA line pulls the flexure 422 toward the support structure 411, causing the end of the flexure 422 to rotate about its fixed point on the support member and / or translate relative to that fixed point. This, in turn, causes a change in the orientation of the first portion 402a of the SMA line, thereby contributing to increased gearing. In fact, the sharper the angle α between the flexure and the first portion 402a of the SMA line, the higher the gearing can be achieved for a given amount of line contraction. Thus, it has been demonstrated that the degree of stroke amplification can be fine-tuned by changing the orientation of the flexure 422 relative to the first portion 402a of the SMA line. However, if the angle α between the flexure and the first portion 402a of the SMA line decreases below a given limit, such as α < 10°, the movement of the movable part may become unstable or jittery.

[0128] Referring back to the second embodiment with reference to FIG3, it can be observed that an acute angle is formed between the first portion 302a of the SMA line and the flexure 322. Therefore, the second embodiment of FIG3 also produces a certain degree of stroke amplification during use.

[0129] On the other hand, the stroke of actuator 410 can be shortened by reducing its transmission. For example, as Figure 4BAs shown, the flexure 422 is oriented away from the movable part. That is, the angle α between the flexure 422 and the first portion 402a of the SMA line becomes an obtuse angle, and is shallower and gentler than the acute angle β between the flexure 422 and the second portion 402b of the SMA line. In this arrangement, the rotation and / or translation of the flexure 422 is significantly reduced, and therefore the change in orientation of the first portion 402a of the SMA line is correspondingly reduced. Thus, such an arrangement reduces the transmission, thereby reducing the stroke of the SMA actuator 410. For example, in the extreme case where the flexure 422 is arranged in a straight line with the first portion of the SMA line, such as α = 90°, the movement of the movable part can be equal to the contraction of the SMA line. That is, in this arrangement, there is essentially no amplification. In some applications, a reduction in stroke amplification, such as α > 90°, may be desirable because it provides more precise and stable motion control as well as increased force.

[0130] As shown in the figure, the amplification of the motion stroke can be predefined to suit the application. That is, the actuator 410 can be manufactured with a flexure 422 oriented at a predetermined angle α relative to the first portion 402a of the SMA line.

[0131] In some other embodiments, the flexure 422 may be rotatably attached to the support member 420 at a fixed point, allowing the degree of magnification to vary during use. That is, the flexure 422 may be adjustable to various positions to achieve variable magnification of travel. For example, the flexure 422 may be connected to the support member 420 via a lockable pivot, such that the orientation of the flexure 422 can be adjusted when the lockable pivot is in the unlocked position.

[0132] The lockable pivot can be mechanically or electronically controlled and / or actuated by a controller to vary the travel amplification to accommodate different operating modes. For example, a smaller degree of travel amplification can be used during normal operation due to relatively low OIS requirements. However, when the electronic equipment is subjected to higher levels of vibration or shaking, such as when used during sporting events, the travel amplification can be increased accordingly to meet higher OIS requirements. Furthermore, this arrangement allows the available travel to be distributed or allocated between two vertical axes to accommodate different functions, such as OIS in the XY plane and AF on the Z-axis.

[0133] In summary, stroke amplification can be achieved in the following ways:

[0134] 1. Amplify the motion generated by the line by controlling the direction of movement or rotation of intermediate components (such as the flexural body or movable part).

[0135] 2. Increase the length of the line by changing the direction of the force and motion generated by the line, so as to allow the motion generated by the two regions of the line to be added together, while keeping the mechanism within the desired dimensions (e.g., rollers or hooks).

[0136] Figure 5 A side view of an SMA actuator 510 according to a fourth embodiment of the present invention is shown. As seen from the side of the actuator 510, a pair of SMA lines 502 are provided connecting the movable member 513 and the support structure 511. In this embodiment, the first portion of the SMA lines 502 is arranged at an acute angle α relative to the flexure member 522 to provide a greater degree of stroke amplification.

[0137] Similar to Figure 4A A third embodiment shows a pair of SMA lines 502 supported or interfered with by corresponding ends of a flexure 522. The flexure is adjustablely rotatable about a support member 520. In this embodiment, when viewed from the side of the actuator 502, the first portions 502a of the SMA lines intersect each other, resulting in a reduced footprint. However, in other embodiments, the first or second portions of the pair of SMA lines 502 may be aligned with... Figure 2 The first embodiment shown extends parallel to each other and substantially in a direction perpendicular to the optical axis in a similar manner.

[0138] Contrary to the previous embodiment, the support member 520 includes a crimp portion 523 for attaching a first portion 502a of the SMA line and a flexure 522 for supporting the SMA line 502. In this embodiment, the flexure 522 is positioned closer to the crimp portion 523 on the support structure 511 than to the crimp portion mounted on the movable member 513. As a result, the first portion 502a of the SMA line is shorter in length and extends with a steeper gradient compared to the second portion 502b of the SMA line.

[0139] The flexure 522 extends along the optical axis and is compliant in the plane in which the SMA line 502 extends. Therefore, during contraction, the movement in the SMA line 502 compresses the flexure 522 and thereby deforms the respective flexure arms of the flexure 522, resulting in the ends of the flexure 522 rotating about a fixed point of the flexure 522 and / or translating relative to the fixed point of the flexure 522.

[0140] In the illustrated embodiment, the flexure 522 is rotatably attached to the support member 520 at a corresponding fixed point. The flexure 522 is adjustable to various positions to achieve a similar configuration to... Figure 4A and Figure 4B The third embodiment shown achieves variable amplification of the displacement of the movable part 513.

[0141] like Figure 5As shown, the first portion 502a and the second portion 502b of the SMA line 502 are tilted relative to the optical axis O by angles α and β, respectively. Figure 3A Compared to the second embodiment shown, the first portion 502a of the SMA line is inclined with a steeper gradient, and therefore, this arrangement can advantageously increase the stroke amplification of the actuator 510.

[0142] Figures 2 to 5 The illustrated embodiment relies on using rollers or flexures to support multiple segments of the SMA line, resulting in two distinct and non-parallel sections of the SMA line. Advantageously, such an arrangement allows the relatively long SMA line to extend substantially along the entire length / width of the actuator. However, in some other embodiments, a flexure arm can be provided instead of one of the two sections of the SMA line, such as a second section connected to a movable component. That is, the length of the SMA line can be reduced accordingly to accommodate the additional flexure arm. However, if a stroke amplification arrangement is used, this arrangement does not necessarily reduce the achievable stroke.

[0143] Figure 6 and Figure 7 Side views of SMA actuators 610 and 710 according to the fifth and sixth embodiments of the present invention are shown respectively. (Refer to...) Figure 6 The side view shows a pair of parallel-extending SMA lines 602 connecting the support structure 611 and the flexure device (an example of a force adjustment mechanism) 622. However, in other embodiments, when viewed from the side, the pair of SMA lines 602 may be aligned with... Figure 2 The arrangements shown are similar and intersect each other to reduce the space occupied by the actuators.

[0144] The flexure device 622 includes a first flexure arm (e.g., a force-adjusting flexure) 622a that extends between a fixed point on the support member 620 and a connector (e.g., a movable portion) 622b of the flexure device (e.g., a force-adjusting mechanism) 622. In practice, the first flexure arm 622a and the connector 622b correspond to those in Figures 3 and 4. Figure 5 The various flexural elements 322, 422, and 522 shown are illustrated.

[0145] The flexure device 622 also includes a second flexure arm (example of a connecting rod) 622c connected between the movable member 613 and the connector 622b. More specifically, the second flexure arm 622c replaces the second portion of the SMA line in the foregoing embodiment and is responsible for converting the force from the SMA line 602 into motion of the movable member 613. Each of the second flexure arms 622c is tilted relative to the optical axis O, optionally at an angle greater than the “minimum line angle” defined above.

[0146] In the illustrated embodiment, both the first flexible arm 622a and the second flexible arm 622c are flexible and / or elastically deformable, and are compliant only in the plane in which the SMA line 602 extends. This allows the movable component to return to its default position and maintains tension in the SMA line 602 when it is not energized. In some other embodiments, the first flexible arm 622a and / or the second flexible arm 622c may be replaced by a pivoting rigid member that does not deform during use.

[0147] Unlike the second portion of the SMA line in the previous embodiment, the second flexible arms 622c do not retract during use, and therefore they have no effect on the total displacement / stroke of the movable component. To ensure sufficient achievable stroke, the first flexible arms 622a each extend from the support member 620 toward the movable member 613 at an acute angle relative to the optical axis O. More specifically, such an arrangement requires a sharper angle α between the first flexible arms 622a and their corresponding SMA lines 602.

[0148] During contraction, the SMA line 602 pulls the first flexural arm 622a toward the support structure 611, causing the connector 622b to rotate about its fixed point on the support member 620 and / or translate relative to that fixed point. This, in turn, results in a change in the orientation of the SMA line 602 and contributes to increased transmission. As in the previous embodiments, the sharper the angle α between the first flexural arm 622a and the SMA line 602, the higher the transmission can be achieved with a given amount of line contraction. For example, by having a smaller angle α between the first flexural arm 622a and the SMA line 602, according to... Figure 7 The actuator 710 of the sixth embodiment shown can achieve a greater stroke.

[0149] There are many variations of the flexural elements 622 and 722, each operating on the same principle. For example, Figure 8 A side view of an SMA actuator 810 according to a seventh embodiment of the present invention is shown. Similar to... Figure 6 and Figure 7 In the fifth and sixth embodiments, the SMA actuator 810 includes a support structure 811, a movable component 813 movable relative to the support structure 811, and an SMA line extending orthogonally to the optical axis. The SMA line has a first end attached to the support structure and a second end attached to a flexural body (movable body) 822b of the flexure device 822. The flexure device 822 also includes a first flexural arm 822a and a second flexural arm 822b respectively attached to the support structure 811 and the movable component 813.

[0150] Although the flexure devices 822, 622, and 722 differ in appearance, flexure device 822 operates on the same principle as flexure devices 622 and 722 used in the preceding embodiments. That is, because the flexure body 822b is anchored to the support structure 811, during contraction, the laterally extending SMA lines 802 cause the first flexure arm 822a to bend, and cause the flexure body 822b (as shown in the previous embodiments) to... Figure 8 (as shown, rotating counterclockwise). This rotation increases the stroke of the second flexural arm 822c, and thus drives the amplified movement of the movable part.

[0151] Advantageously, such as Figure 8 The second flexural arm 822c shown is positioned in a straight line with the flexural body 822b, thereby allowing the laterally extending SMA line 802 to span the entire length of the movable part 813, and thus further increasing the available travel.

[0152] Figures 6 to 8 An embodiment is depicted in which the force adjustment mechanism is implemented by a force adjustment flexure and the connecting link is implemented by a flexure arm. However, in general, the force adjustment mechanism can be implemented by any mechanism capable of amplifying the displacement or force applied to the force adjustment mechanism by the SMA line. The force adjustment mechanism can, for example, include a flexure, a lever arm, or a roller. Similarly, the connecting link can be implemented by any element or device capable of achieving the dual function of transmitting actuation force to a second component (movable component) and providing compliance in a direction perpendicular to the actuation force direction.

[0153] Figure 9A and Figure 9B An embodiment is depicted in which the connecting link includes a rolling support 922c instead of, for example, a flexure. When the SMA line 902 contracts, the SMA line 902 applies an input force to the force-adjusting flexure 922a. The force-adjusting flexure 922a adjusts the input force, particularly in the depicted embodiment, reducing the input force and increasing the stroke of the SMA line 902, and providing an output force to the rolling support 922c. For example, the rolling support 922c is held in a compressed state due to tension in the opposing SMA lines 902. The rolling support 922c transmits the output force to provide an actuating force for moving the second member 913 (i.e., the movable member) relative to the first member 911 (i.e., the support structure).

[0154] Figure 9A and Figure 9B The differences between the embodiments stem from the arrangement of the force-adjusting flexure 922a and the rolling support 922c. Figure 9AIn the middle, the contraction of the top SMA line 902 is redirected by the force adjusting flexure 922a to the lower left direction, so as to apply an actuating force to the second component 913 in the lower left direction. The contraction of the bottom SMA line 902 is redirected by the force adjusting flexure 922a to the upper left direction, so as to apply an actuating force to the second component 913 in the upper left direction. Figure 9B In the middle, this arrangement is exactly the opposite, so that the contraction of the top SMA line 902 results in an actuation force in the upper left direction, and the contraction of the bottom SMA line 902 results in an actuation force in the lower left direction.

[0155] In addition, Figure 9A and Figure 9B In this context, the distance between the connection point of the force-adjusting flexure to the first component 911 (i.e., the support structure) and the connection point to the SMA line 902 is greater than the distance between the connection point of the force-adjusting flexure to the first component 911 (i.e., the support structure) and the connection point to the connecting rod (implemented by the rolling support 922c). This further facilitates stroke amplification. Generally, the force adjustment mechanism in any of the foregoing embodiments can achieve stroke or force amplification due to the relative positioning of the connection to the SMA line and the connection to the connecting rod, as a supplement to, or as an alternative to, stroke or force amplification resulting from the angle of the force adjustment mechanism relative to the input force provided by the SMA line and the output force provided to the connecting mechanism.

[0156] Figure 10 A tenth embodiment of the SMA actuator 1010 is depicted, which is similar to the following main differences. Figure 6 The fifth embodiment is depicted in the text.

[0157] In the fifth embodiment, each force-adjusting flexure 622a is connected to a fixed point on the support member 620, which is positioned partially along one side of the SMA actuator 610. In contrast, in the tenth embodiment, each force-adjusting flexure 1022a is connected to a fixed point (e.g., on the support structure 1011) positioned at or near a corner of the SMA actuator 1010. Each movable portion 1022b is connected to the support structure 1011 via the force-adjusting flexure 1022a and is therefore also positioned at or near a corner. Thus, each SMA line 1002 can extend substantially all (e.g., >80%) of its lateral length. Therefore, longer SMA lines 1002 (which typically enables greater movement) can be accommodated in an SMA actuator of a given lateral dimension. In each actuation unit of the fifth embodiment, the connecting link 622c and the SMA line 602 extend from the movable portion 622b in substantially opposite directions (and are connected to the support structure 611 and the movable component 613 at or near different corners of the SMA actuator 610, respectively). In contrast, in each actuation unit of the tenth embodiment, the connecting link 1022c and the SMA line 1002 extend from the movable portion 1022b in substantially the same direction along the side (and are connected to the support structure 1011 and the movable component 1013 at or near the same corners as the SMA actuator 610, respectively). Therefore, in order to generate tension in the connecting link 1022c due to tension in the SMA line 1002, the force-adjusting flexure 1022a should be connected to a point on the movable portion 1022b between the points where the connecting link 1022c and the SMA line 1002 are connected.

[0158] In this example, in each actuation unit, the SMA line 1002 is positioned toward the top or bottom (as appropriate) of the SMA actuator 1010, and the connecting link 1022c is positioned toward the center of the SMA actuator 1010. In each actuation unit, the SMA line 1002 can have any suitable position along the main axis, and the connecting link 1022c can have any suitable position along the main axis and any suitable inclination relative to the main axis (e.g., extending upwards or downwards from the movable portion 1022b). The two actuation units on each side can be separated from each other along the main axis, or the two actuation units on each side can overlap.

[0159] Figure 11 An eleventh embodiment 1110 of the SMA actuator is described, which is similar to the following main differences. Figure 10 The tenth embodiment is depicted in the text.

[0160] In the eleventh embodiment, each connecting link 1122c includes a hairpin such that the connecting link 1122c has a first portion extending from the movable portion 1122b along a first direction to the hairpin, and then has a second portion extending from the hairpin along a second direction (substantially opposite to the first direction) before being connected to the movable member 1113. Therefore, in each actuation unit, the SMA line 1102 and the connecting link 1122c are connected to the support structure 1111 and the movable member 1113 at or near different corners of the SMA actuator 1110, respectively.

[0161] In each actuation unit of the eleventh embodiment, when the SMA line 1102 is in a tensioned state, the second component of the connecting rod 1122c is also in a tensioned state, and the connection points of the relevant components 1102, 1122a, and 1122c relative to the movable component 1122b are arranged accordingly. However, in other examples, the actuation unit may be constructed differently.

[0162] In other examples, the connecting rod 1122c can have a more complex shape.

[0163] Figure 12 A twelfth embodiment 1210 of the SMA actuator is described, which is similar to the following main embodiments, except for the following key differences. Figure 10 The tenth embodiment is depicted in the text.

[0164] In each actuation unit of the tenth embodiment, when the SMA line 1002 is in a tensioned state, the connecting rod 1022c is also in a tensioned state. In contrast, in each actuation unit of the twelfth embodiment, when the SMA line 1202 is in a tensioned state, the connecting rod 1222c is in a compressed state.

[0165] Therefore, in the twelfth embodiment, each connecting link 1222c may be provided with additional features to increase its compressive strength, such as an L-shaped cross-section. It will be understood that these additional features should not unduly affect the compliance of the connecting link 1222c in a direction perpendicular to its length. In some examples, such additional features may not be present.

[0166] In the twelfth embodiment, for the purpose of stroke amplification, the SMA line 1202 is connected to a point on the movable part 1222b between the point where the force adjustment flexure 1222a and the connecting rod 1222c are connected.

[0167] The aforementioned SMA actuator assembly includes an SMA wire. The term "shape memory alloy (SMA) wire" can refer to any element containing an SMA. An SMA wire can have any shape suitable for the purposes described herein. An SMA wire can be elongated and can have a circular cross-section or any other cross-section shape. The cross-section can vary along the length of the SMA wire. It is also possible that the length of the SMA wire (as defined in any way) can be similar to one or more other dimensions of the SMA wire. An SMA wire can be flexible, or in other words, it can be supple. In some examples, when connected in a straight line between two elements, the SMA wire can only exert tension to force the two elements together. In other examples, the SMA wire can bend around the element, and the SMA wire can apply a force to the element as it tends to straighten under tension. An SMA wire can be beam-like or rigid and capable of applying different forces (e.g., non-tension) to the element. An SMA wire may or may not include non-SMA materials and / or components. For example, an SMA wire may include an SMA core and a coating of a non-SMA material. Unless the context otherwise requires, the term "SMA line" can refer to any configuration of an SMA line that acts as a single actuating element, such that the single actuating element can be independently controlled to generate a force acting on the element. For example, an SMA line may comprise two or more sections of an SMA line arranged mechanically in parallel and / or in series. In some arrangements, an SMA line may be a portion of a long SMA line. Such a large SMA line may comprise two or more sections that can be individually controlled, thereby forming two or more SMA lines.

Claims

1. A shape memory alloy (SMA) actuator assembly, comprising: A first component and a second component, the first component and the second component being movable relative to each other; as well as One or more actuation units, each actuation unit comprising: - A force adjustment mechanism, which is connected to the first component; - A connecting link, which connects the force adjustment mechanism and the second component; and - An SMA line, the SMA line connecting the first component and the force adjustment mechanism, is used to apply an input force to the force adjustment mechanism, thereby causing the force adjustment mechanism to apply an output force to the connecting rod, and causing the connecting rod to apply an actuating force to the second component, wherein the connecting rod is compliant in a direction perpendicular to the direction of the actuating force; and The one or more actuation units are arranged to drive the second component relative to the first component at least along the main axis, and the shortest side of the SMA actuator assembly extends along the main axis.

2. The SMA actuator assembly of claim 1, wherein, The SMA line is arranged at a non-zero angle to the principal axis.

3. The SMA actuator assembly of claim 1, wherein, The force adjustment mechanism is configured such that, in response to a change in the length of the SMA line, the end of the SMA line connected to the force adjustment mechanism moves a first distance relative to the first component, and the end of the connecting rod connected to the force adjustment mechanism moves a second distance relative to the first component, the second distance being greater than the first distance.

4. The SMA actuator assembly according to claim 1, wherein, The force adjustment mechanism is configured such that, in response to a change in the length of the SMA line, the end of the connecting link connected to the force adjustment mechanism moves a second distance relative to the first component, the second distance being greater than the change in the length of the SMA line.

5. The SMA actuator assembly according to claim 1, wherein, The connecting link is a flexure, wherein the flexure is elongated and rigid along its length, and compliant in a direction perpendicular to its length.

6. The SMA actuator assembly of claim 1, wherein, The connecting rod includes a ball bearing or a sliding bearing.

7. The SMA actuator assembly according to any one of claims 1 to 6, wherein, The force adjustment mechanism includes: The movable part, the SMA line and the connecting rod are connected to the movable part; and A force-adjusting flexure is connected between the movable portion and the first component and is configured to bend in response to the input force.

8. The SMA actuator assembly of claim 7, wherein, At least one of the connecting rod and the force-adjusting flexure is configured to have lower stiffness in the direction along the main axis than in any other direction, in order to facilitate the movement of the movable part.

9. The SMA actuator assembly of claim 7, wherein, The movable part is integrally formed with the force-adjusting flexure and / or the connecting rod.

10. The SMA actuator assembly of claim 7, wherein, The force-adjusting flexure is elongated and rigid along its length, and compliant in a direction perpendicular to its length.

11. The SMA actuator assembly according to any one of claims 1 to 6, wherein, The force adjustment mechanism includes a roller.

12. The SMA actuator assembly according to any one of claims 1 to 6, comprising eight SMA lines.

13. The SMA actuator assembly of claim 12, wherein, The eight SMA lines are configured together to guide the movement of the second component in any direction.

14. The SMA actuator assembly of claim 12, comprising eight actuation units.

15. The SMA actuator assembly of claim 14, wherein, The eight actuation units apply actuation forces to the second component, wherein the actuation forces are symmetrically arranged, and due to the symmetrical arrangement, different combinations of the actuation forces can drive the movement of the second component with multiple degrees of freedom.

16. The SMA actuator assembly of claim 15, wherein, The movement includes tilting in any direction.

17. The SMA actuator assembly according to any one of claims 1-6, 8-10, and 13-16, wherein, At least one SMA line includes a first SMA line and a second SMA line, the first SMA line and the second SMA line being configured to drive the movement of the second component in a first direction and a second direction opposite to the first direction, respectively.

18. The SMA actuator assembly according to any one of claims 1-6, 8-10, and 13-16, wherein, At least one SMA line comprises four pairs of SMA lines, wherein the four pairs of SMA lines are arranged symmetrically around the main axis.

19. The SMA actuator assembly according to any one of claims 1-6, 8-10, and 13-16, wherein, The second component includes one or more lenses or image sensors, wherein the main axis is the optical axis of the one or more lenses or a photosensitive area perpendicular to the image sensor.

20. The SMA actuator assembly of claim 19, configured to provide only autofocus in the camera assembly.

21. The SMA actuator assembly of claim 19, configured to provide only optical image stabilization in the camera assembly.

22. The SMA actuator assembly of claim 19, configured to provide autofocus and optical image stabilization in a camera assembly.

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