Actuator assembly

Abstract

An actuator assembly (10) comprising: a first portion (5); a second part (6) arranged to be movable relative to the first part; eight actuation units (80) arranged to, upon actuation, move the second portion relative to the first portion, where each actuation unit comprises: a body portion (82); a force adjustment flexure (84) connected between the body portion and the first portion; a coupling flexure (83) connected between the body portion and the second portion; an SMA element (2) arranged to exert an input force on the body portion upon actuation, thereby deforming the force adjustment flexure, thereby adjusting the input force and causing the coupling flexure to exert an actuation force (Fa) on the second portion; wherein the eight actuation units (80) are in an arrangement such that, upon selective actuation, the eight actuation units (80) exert a non-collinear force on the second part relative to the first part, which non-collinear force enables the second part to move in up to six degrees of freedom relative to the first part.

Description

field

[0001] The present application relates to actuator assemblies, and in particular to shape memory alloy (SMA) actuator assemblies. background

[0002] SMA actuator assemblies can be used in miniature cameras to achieve optical image stabilization and / or autofocus (AF). For example, WO 2011 / 104518 A1 discloses an SMA actuator that uses a specific arrangement of eight SMA wires to move a movable element to achieve OIS and / or AF.

[0003] Typically, the range of motion (also known as "stroke") of such an SMA actuator assembly is limited by the maximum contraction of the SMA wire, and the actuation force is limited by the maximum force the SMA wire can generate. To increase the range of motion or actuation force, longer or thicker SMA wires can be used, but this may come at the expense of increased cost, size, and / or power, which may not be practical in miniature applications.

[0004] WO 2022 / 084699 A1 discloses an actuator assembly comprising at least one actuation unit comprising an SMA wire, which upon actuation moves a movable portion relative to a support structure. The actuation unit can be configured to increase the stroke or actuation force and / or redirect the force applied by the SMA wire. Overview

[0005] According to one aspect of the present invention, an actuator assembly is provided, comprising: a first part; a second part arranged to be movable relative to the first part; eight actuating units arranged to cause the second part to move relative to the first part upon actuation, wherein each actuating unit comprises: a main body; a force-modifying flexure connected between the main body and the first part; a coupling flexure connected between the main body and the second part; an SMA element, wherein the SMA element is arranged to apply an input force to the main body upon actuation, thereby deforming the force-modifying flexure, thereby modulating the input force and causing the coupling link to apply an actuating force to the second part; wherein the eight actuating units are in such an arrangement that, upon selective actuation, the eight actuating units apply a non-collinear force on the second part relative to the first part, wherein the non-collinear force is capable of causing the second part to move relative to the first part in up to six degrees of freedom.

[0006] It should be understood that reference to a component being "connected" between two other components means, for example, that the component is directly or indirectly connected to each of the other components. Such indirect connection may involve connection via an additional component (e.g., a connector) having a fixed position relative to one of the other components. Such indirect connection may also involve connection via an additional component that is movable relative to the other component. For example, an SMA element may be connected to one of the first and second parts via an additional flexure, for example, as described in WO 2022 / 144541 (which is incorporated herein by reference to the fullest extent permitted by law).

[0007] In some embodiments, the actuation unit is actuated to cause the second part to rotate relative to the first part about any axis substantially perpendicular to the main axis and optionally about the main axis (in both directions (sense)). Such an embodiment can achieve a 2-axis or 3-axis modular tilt OIS. In such an embodiment, the actuator assembly may include a bearing arrangement between the first part and the second part. The bearing arrangement can be configured to allow the second part to rotate relative to the first part about any axis substantially perpendicular to the main axis and optionally about the main axis. Such a bearing arrangement can limit other types of movement, such as translational movement of the second part relative to the first part, and thus can help improve the performance of the actuator assembly. The bearing arrangement may include, for example, one or more gimbals.

[0008] The non-collinear forces can cause the second portion to move relative to the first portion in two or more rotational degrees of freedom or three translational degrees of freedom.

[0009] In each actuation unit, the SMA element may be connected between the body portion and the first portion.

[0010] The eight actuation units may be arranged into four pairs of actuation units, wherein each pair of actuation units is arranged on a different side of the second portion.

[0011] The actuator assembly may comprise a main axis, and wherein each of the side portions are arranged about the main axis, optionally wherein adjacent sides are substantially perpendicular, such that the four sides form a quadrilateral shape when viewed along the main axis.

[0012] The coupling flexure of at least one of the actuation units may be inclined at an angle of 30 to 60 degrees, optionally 35 to 55 degrees, preferably 40 to 50 degrees relative to a plane substantially perpendicular to the main axis.

[0013] The arrangement of any pair of actuation units along either side of the actuator assembly may have 180 degree rotational symmetry about the primary axis with the arrangement of the actuation units on the opposite side of the actuator assembly.

[0014] The arrangement of any pair of actuation units along any given side of the actuator assembly may have mirror symmetry with the arrangement of actuation units along an adjacent side of the actuator assembly about a plane intersecting the two sides and containing the major axis.

[0015] Each pair of actuation units may comprise a respective first actuation unit and a respective second actuation unit, wherein for at least one pair of actuation units the arrangement of the second actuation unit corresponds to a reflection of the first actuation unit in a plane containing the main axis.

[0016] Each pair of actuation units may comprise a respective first actuation unit and a respective second actuation unit, wherein for at least one pair of actuation units the arrangement of the second actuation unit corresponds to a reflection of the first actuation unit in both a plane containing the main axis and a plane substantially perpendicular to the main axis.

[0017] Each pair of actuation units may be arranged such that the actuation units have 180 degrees of rotational symmetry around an axis perpendicular to one side on which the pair of actuation units are arranged.

[0018] For at least one pair of actuation units, the corresponding coupling flexures may be substantially parallel.

[0019] The respective force-adjusting flexures of at least one of the pairs of actuation units may be substantially parallel.

[0020] For at least one pair of actuating units, the connecting flexure of one actuating unit may be connected to the side of the second portion at or near one longitudinal end of the side, and the connecting flexure of the other actuating unit of the pair may be connected to the side at or near the other longitudinal end of the side of the second portion.

[0021] For at least one pair of actuation units, the force regulating flexure of each actuation unit in the pair of actuation units can be connected to a central portion of a side of the first part, optionally wherein the force regulating flexure is connected to the side at a point that is greater than 25% of the distance along the side and less than 75% of the distance along the side.

[0022] For at least one pair of actuating units, the main body portion of each actuating unit in the pair of actuating units can be positioned at a central area of ​​a side of the first part, optionally, wherein the main body portion is positioned along the side in an area that is greater than 25% of the distance along the side and less than 75% of the distance along the side.

[0023] For at least one pair of actuation units, the force adjustment element of each actuation unit of the pair may be arranged to be placed under compression by the respective body portion when the respective SMA element exerts an input force on the respective body portion.

[0024] The actuation units can be arranged such that when the SMA elements exert an input force on the corresponding body portion, the body portion exerts a compressive force on the corresponding force modulating flexure in a direction at least partially toward the point where the corresponding force modulating flexure connects to the first portion. The compressive force can be directed at least partially toward the center of the side portion where the pair of actuation units are arranged. The connection between the force modulating flexure and the first portion can be positioned closer to the center of the side portion relative to the connection between the force modulating flexure and the body portion.

[0025] The coupling flexure, the SMA element, and the force modulation flexure may each extend from the main body portion in a direction at least partially toward the same longitudinal end of the side portion.

[0026] In each actuation unit, the coupling flexure may be connected to a central portion of a side of the second portion, optionally wherein the coupling flexure is connected to the side at a point greater than 25% and less than 75% of the distance along the side.

[0027] In each pair of actuation units, the force adjustment flexure of one actuation unit is connected to the side of the first portion at or near one longitudinal end thereof, and the force adjustment flexure of the other actuation unit may be connected to the side at or near the other longitudinal end thereof.

[0028] In each pair of actuating units, the connecting link of one actuating unit can extend from the main part to the second part in a direction at least partially toward one longitudinal end of the side part, and the connecting link of the other actuating unit can extend from the main part to the second part in a direction at least partially toward the other longitudinal end of the side part.

[0029] A connection point between the coupling link and the second portion of each actuating unit may be located closer to an opposite longitudinal end of the side portion than to a longitudinal end of the side portion at which the corresponding body portion is arranged.

[0030] In each actuation unit, the coupling link may extend from the main body portion to the second portion in a direction at least partially toward a longitudinal end of the side portion, and the SMA element may extend from the main body portion to the first portion in a direction at least partially toward the same longitudinal end of the side portion.

[0031] The SMA elements of each pair of actuation units may cross when viewed perpendicularly to the side on which the pair of actuation units are arranged.

[0032] The SMA elements of each pair of actuation units may not cross when viewed perpendicularly to the side on which the pair of actuation units are arranged, optionally wherein the SMA elements of each pair of actuation units are parallel.

[0033] The main body portion, the force adjustment flexure and the coupling flexure of each pair of actuation units may be integrally formed.

[0034] The main body portion of each actuation unit may include a first arm extending between a connection point to the force modulating flexure and a connection point to the SMA wire, and / or a second arm extending between a connection point to the force modulating flexure and a connection point to the coupling flexure. The first arm may extend away from the end of the SMA wire connected to the first portion, and / or the second arm may extend away from the end of the coupling flexure connected to the second portion. In each actuation unit, the first arm and / or the second arm may extend away from the connection point to the force modulating flexure in a direction at least partially toward the other longitudinal end of the side portion. In each actuation unit, the first arm and / or the second arm may extend away from the connection point to the force modulating flexure in a direction at least partially toward the same longitudinal end of the side portion.

[0035] Each actuation unit may be configured such that the force modulating flexure amplifies an amount of actuation of the SMA wire into a relatively greater amount of movement of the second portion relative to the first portion.

[0036] A camera assembly may be provided, comprising: an actuator assembly; one or more lenses included in one of a first portion and a second portion of the actuator assembly; and an image sensor included in the other of the first portion and the second portion of the actuator assembly; wherein the actuator assembly is configured to move the one or more lenses and the image sensor relative to each other in three translational degrees of freedom.

[0037] A camera assembly may be provided, comprising: an actuator assembly; a support structure comprising one of a first portion and a second portion of the actuator assembly; a module included in the other of the first portion and the second portion of the actuator assembly, wherein the module comprises one or more lenses and an image sensor; wherein the actuator assembly is configured to rotate the module relative to the support structure in two or more rotational degrees of freedom.

[0038] In another aspect, the actuator assembly can be as described above, except that one or more actuating units can be connected between the first portion and the second portion in opposite directions, i.e., one or more actuating units can have a force regulating flexure connected between the main body portion and the second portion, a coupling flexure connected between the main body portion and the first portion, and an SMA element that can be connected between the main body portion and the second portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Certain embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1A An example of an SMA actuator assembly comprising eight SMA wires is depicted; Figure 1B depicts the actuator assembly; Figure 2A and Figure 2B Each depicts a pair of actuating units; Figure 3 depicts an SMA actuator assembly comprising an arrangement of eight actuation units; Figure 4A and Figure 4B Each depicts a pair of actuating units; Figure 5A and Figure 5B Each depicts a pair of actuating units; Figure 6 depicts an SMA actuator assembly comprising an arrangement of eight actuation units; Figure 7 A pair of actuating units is depicted; Figure 8 A pair of actuating units is depicted; Figure 9 A pair of actuating units is depicted; Figure 10 A pair of actuating units is depicted; Figure 11 An SMA actuator assembly comprising an arrangement of eight actuation units is depicted. Detailed description

[0040] Conventional eight-wire actuator assembly FIG1 shows an exploded view of a known shape memory alloy (SMA) actuator wire device 10 used in a miniature camera. SMA actuator device 10 includes a support structure 5 (also referred to herein as “first portion 5” or “static portion 5”), which includes a base 11, which is an integrated chassis and sensor holder for mounting an image sensor (not shown), and a screening can 12 attached to support structure 11. SMA actuator device 10 includes a movable portion 6 (also referred to herein as “second portion 6” or “moving portion 6”), which is a lens assembly including a lens holder 13 that carries at least one lens (not shown) configured to focus an image on the image sensor.

[0041] In some other embodiments, support structure 11 may include a lens assembly including a lens carrier 13 carrying at least one lens (not shown), wherein movable portion 13 may include a sensor holder for mounting an image sensor, and wherein the at least one lens is configured to focus an image on the image sensor. That is, in these alternative embodiments, the image sensor is movable relative to the (fixed or movable) lens.

[0042] In some other embodiments, the movable portion 6 may include both an image sensor and a lens assembly configured to focus an image on the image sensor.

[0043] The lens assembly defines an optical axis. The image sensor captures the image and can be of any suitable type, such as a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) device. Each lens can have a diameter of 20 mm or less, such as 12 mm or less.

[0044] In this example, the actuator 10 includes eight SMA wires 2, each of which is attached between a static portion 5 and a moving portion 6. When viewed along the optical axis and along a first direction, a pair of mutually crossing SMA wires 2 is provided on each of the four sides of the SMA actuator device 10. The SMA wires 2 are attached to the static portion 5 and the moving portion 6 in such a configuration that, when heated, the SMA wires 2 contract and thereby apply an actuation force Fa to provide relative movement of the moving portion 5 with multiple degrees of freedom, for example, to provide both autofocus (AF) and optical image stabilization (OIS).

[0045] Thus, with respect to each pair of SMA wires 2, the SMA wires 2 are attached at one end to two static mounting portions 15, which are themselves mounted to the static portion 5 for attaching the SMA wires 2 to the static portion 5. The static mounting portions 15 are adjacent to each other but separated to allow them to be at different electrical potentials.

[0046] Similarly, with respect to each pair of SMA wires 2, the SMA wires 2 are attached at one end to a mobile mounting portion 16, which is itself mounted to the moving portion 6 for attaching the SMA wires 2 to the moving portion 6. The moving portion 6 also includes a conductive ring 17 connected to each mobile mounting portion 16 for electrically connecting the SMA wires 2 together at the moving portion 6.

[0047] The static mounting portion 15 and the movable mounting portion 16 include crimping tabs 23 that can form a crimp and be used to retain the SMA wire 2. The movable mounting portion 16 can include an electrical connection tab 31 for providing an electrical connection to the conductive ring 17. Thus, in the example shown in FIG1 , the crimping tabs 23 that form the crimp are an integral part of the static portion 15 and the movable portion 16 of the actuator device 10. Methods for forming the crimp and capturing the SMA wire within the crimping tabs 23 are described in International Patent Publication No. WO2016 / 189314.

[0048] Figure 1B The actuator assembly 10 is schematically shown. As described above, the movable portion 6 can move relative to the support structure 5. When the actuator assembly 10 is included in, for example, a device (which may be a portable electronic device such as a smartphone), the support structure 5 can be fixed relative to the main body of the device. However, in general, the support structure 5 need not be stationary and can be movable relative to or within the device. Each SMA wire 2 is configured to apply an actuation force Fa that can cause the movable portion 6 to move relative to the support structure 5.

[0049] The SMA wires 2 may be arranged such that the movable portion 6 may be supported (i.e., suspended) on the support structure 5 solely by the SMA wires 2. In other words, the SMA wires 2 may be arranged such that the movable portion 6 may be positioned in a suspended position relative to the support structure 5 (e.g., a position in which the movable portion 6 is not in contact with the support structure 5) solely by the SMA wires 2, as shown. Figure 1B shown.

[0050] The principal axis P may be defined with reference to the actuator assembly 10 and / or the support structure 5. The principal axis P extends through the actuator assembly 10, for example through the center of the actuator assembly 10. The actuator assembly 10, the support structure 5, and the movable portion 6 extend primarily in a direction perpendicular to the principal axis P. In other words, the actuator assembly 10, the support structure 5, and the movable portion 6 extend less along the principal axis P than in any direction perpendicular to the principal axis P. The principal axis P is the longitudinal axis of the actuator assembly 10 and the support structure 5. For example, when the movable portion 6 is in a central position or orientation (e.g., as Figure 1B As shown), the principal axis P may be parallel to the optical axis of the lens assembly and / or the imaging axis of the image sensor, and / or may coincide with or be colinear with the optical axis and / or the imaging axis.

[0051] The movable part 6 is capable of moving relative to the support structure 5 in up to six degrees of freedom (DOF). In the context of describing the degrees of freedom of movement, the main axis P may also be referred to as the z-axis, and the other two axes perpendicular to the main axis P and to each other may be referred to as the x-axis and the y-axis. The movable part 6 may be movable relative to the support structure 5 in all of the following degrees of freedom: - Tx and Ty: translational movement in the xy plane. In other words, the movable part 6 can be moved independently along the x-axis and the y-axis. The movable part 6 can be moved to any position in the xy plane within the range of movement.

[0052] Rx and Ry: rotational movement (or simply rotation or tilt) about the x-axis and the y-axis. In other words, the movable part 6 can rotate about any axis perpendicular to the main axis P. The movable part 6 can be rotated to any rotational position (i.e., to any orientation) within the range of movement.

[0053] - Tz: translational movement along the z axis. The movable part 6 can be moved to any translational position along the z axis within the range of movement.

[0054] - Rz: rotational movement about the z axis (or simply rotation). The movable part 6 can be rotated to any rotational position (ie to any orientation) within the range of movement.

[0055] As described above, the SMA wire 2 is connected between the support structure 5 and the movable part 6. The SMA wire 2 is arranged to apply an actuation force Fa between the movable part 6 and the support structure 5. Selectively varying the actuation force Fa causes the movable part 6 to move relative to the support structure 5 within the above-mentioned degrees of freedom. Thus, the SMA wire 2 is capable of driving the movement of the movable part 6 relative to the support structure 5.

[0056] The SMA wires 2 are connected such that, upon contraction, the two groups of four SMA wires 2 provide forces having components in opposite directions along the main axis P to effect movement along the main axis P. Each group of SMA wires 2 has two-fold rotational symmetry about the main axis P, such that the SMA wires 2 are relative to each other to effect lateral movement, i.e., movement in a direction perpendicular to the main axis P.

[0057] Assembly 10 also includes a controller (not shown). The controller (also referred to herein as a control circuit) can be implemented in an integrated circuit (IC) chip. The controller generates a drive signal for the SMA wire 2. SMA material has the property that, when heated, it undergoes a solid-state phase change that causes the SMA material to contract. Therefore, applying a drive signal to the SMA wire 2, thereby heating the SMA wire 2 by flowing an electric current, causes the SMA wire 2 to contract, thereby driving relative movement of the movable portion 6. The drive signal is selected to drive relative movement of the movable portion 6 in a desired manner, for example, to achieve optical optical isolation (OIS) by stabilizing the image sensed by the image sensor, or to achieve autofocus (AF) by adjusting the focus of the image sensed by the image sensor. The controller provides the generated drive signal to the SMA wire 2.

[0058] Optionally, assembly 10 also includes a motion sensor (not shown), which may include a 3-axis gyroscope and a 3-axis accelerometer. The motion sensor can generate a signal representing the motion (specifically, vibration or "shake") of assembly 1 , which can be processed to generate a signal representing the desired movement of movable portion 6 to compensate for such shake. A controller receives this signal and can generate a drive signal for SMA wire 2 to achieve OIS.

[0059] Although the actuator assembly 10 is described in conjunction with a miniature camera, it will be understood that the actuator assembly 10 may be used in any device in which it is desired that the movable portion 6 be moved relative to the support structure 5, for example, to provide tactile feedback in a tactile feedback device or to move a projector or display in an augmented reality (AR) or virtual reality (VR) device.

[0060] As shown in FIG1 , a pair of SMA wires 2 is arranged on each of the four sides surrounding a principal axis P, and the pair of SMA wires 2 extends at a certain angle to the principal axis P. There is a "minimum wire angle" required by the actuator to prevent uncontrolled resonance of the SMA wires 2 along the principal axis P. Therefore, to maintain this wire arrangement and prevent such uncontrolled resonance, the height of the actuator is typically increased during magnification. Therefore, if the height (or thickness) of the actuator assembly 10 is important, this known design may be disadvantageous for larger lenses.

[0061] In practice, when the SMA wires 2 are not energized, i.e., when the SMA actuator 10 is powered off and the SMA wires 2 have sufficiently cooled, the SMA wires 2 may no longer be under tension. Therefore, in most cases, a certain degree of slack may be observed in the unenergized SMA wires 2. This may result in free movement of the SMA wires 2 and the lens holder. Since the SMA wires 2 are crossed when viewed from the side, this free movement may result in the SMA wires 2 contacting and rubbing against each other, thereby causing extensive wear of the wires 2.

[0062] To help address these issues, Figure 1A The SMA wire 2 of the actuator assembly 10 may be replaced with an SMA actuation unit 80 described below.

[0063] First Example of Actuator Assembly In the first example actuator assembly 10, Figure 1A The eight SMA wires 2 of the actuator assembly 10 are Figure 2A The actuating unit 80 is replaced by Figure 3 shown.

[0064] Figure 2A Each actuation unit 80 includes several components connected to a main body portion 82. The main body portion 82 is configured not to deform during use (ie, during contraction or actuation of the SMA wire 2). Therefore, the main body portion 82 is relatively rigid.

[0065] Figure 2A Each actuation unit 80 further includes a force-adjusting flexure 84. The force-adjusting flexure 84 is connected between the main body portion 82 and the support structure 5. One end 84m of the force-adjusting flexure 84 is connected to the main body portion 82. The other end 84s of the force-adjusting flexure 84 is connected to the support structure 5. The force-adjusting flexure 84 can allow the main body portion 82 to move relative to the support structure 5 in a direction substantially orthogonal to the force-adjusting flexure 84 when flexed. The force-adjusting flexure 84 effectively allows the main body portion 82 to pivot relative to the support structure 5. The force-adjusting flexure 84 is configured to provide an effective pivot point V, allowing the main body portion 82 to pivot relative to the support structure 5 about the effective pivot point V.

[0066] Figure 2A Each actuation unit 80 further includes an SMA wire 2. The SMA wire 2 is connected between the main body portion 82 and the support structure 5. One end of the SMA wire 2 is connected to the support structure 5, particularly via a crimping portion 35s. The other end of the SMA wire 70 is connected to the main body portion 82, particularly via a crimping portion 35m.

[0067] Figure 2AEach actuating unit 80 further includes a coupling flexure 83. The coupling flexure 83 is connected between the main body 82 and the movable part 6. One end of the coupling flexure 83 is connected to the main body 82. The other end of the coupling flexure 83 is connected to the movable part 6, for example, via a mobile mounting portion 86.

[0068] exist Figure 2A Within each actuation unit 80 , the SMA wire 2 is arranged to exert an input force Fi on the main portion 82 upon contraction. The input force acts parallel to the length of the SMA wire 2 . The force-modifying flexure 84 is arranged to modulate the input force Fi so that the coupling flexure 83 exerts an actuating force Fa on the movable portion 6 . This actuating force Fa is transmitted from the main portion 82 to the movable portion 6 via the coupling flexure 83 . In particular, in the depicted embodiment, the force-modifying flexure 84 is placed in tension upon contraction of the SMA wire 2 . The force-modifying flexure 84 is arranged at an angle and / or offset relative to the SMA wire 2 . Thus, the force-modifying flexure 84 is arranged to deform upon contraction of the SMA wire 2 . The main portion 82 pivots about the effective pivot point V provided by the force-modifying flexure 84 . Thus, the force-modifying flexure 84 converts the input force Fi, particularly its magnitude and direction, into the actuating force Fa. In other words, the force-adjusting flexure 84 and the main body portion 82 adjust the direction and magnitude of the input force Fi to generate the actuation force Fa.

[0069] Figure 2A Each actuation unit 80 can be configured to amplify the movement or force generated by the contraction of the SMA wire 2. In the depicted embodiment, the distance between the input force Fi applied by each SMA wire 2 and the effective pivot point V is less than the distance between the actuation force Fa and the effective pivot point V. Each actuation unit 80 effectively acts as a lever to amplify the contraction movement of the SMA wire 2.

[0070] In some embodiments, at least one actuation unit 80 (preferably each actuation unit 80) is configured such that the force-modulating flexure 84 amplifies the amount of contraction of the SMA wire 2 into a relatively larger amount of movement of the movable portion 6 relative to the support structure 5. For example, the factor of such amplification may be greater than 1.5, preferably greater than 2, and more preferably greater than 3. This may be achieved, for example, by appropriately selecting the distance between the SMA wire 2 and the effective pivot point V, such as by adjusting the angle between the SMA wire 2 and the force-modulating flexure 84, or by varying the extent of the main body portion 82. The angle between the SMA wire 2 and the force-modulating flexure 84 may be in the range of 0 to 45 degrees, preferably in the range of 13 to 40 degrees.

[0071] Figure 2AEach coupling flexure 83 is flexible in a direction perpendicular to the actuation force Fa. This allows the movable part 6 to move in a direction perpendicular to the actuation force Fa of the actuation unit 80 and in a direction perpendicular to the coupling flexure 83.

[0072] As discussed, Figure 2A Each force adjustment flexure 84 is in tension when the corresponding SMA wire 2 contracts. This can reduce the risk of buckling of the force adjustment flexure 84. However, in general, the force adjustment flexure 84 can also be arranged to be in compression when the SMA wire 2 contracts.

[0073] Further details and alternative examples of the actuation unit are described in WO 2022 / 084699 A1, which is incorporated herein by reference to the maximum extent permitted by law.

[0074] As discussed, Figure 2A Each force regulating flexure 84 and the SMA wire 2 are connected at one end to the support structure 5, and Figure 2A Each coupling flexure 83 is connected at one end to the movable part 6. Generally, this arrangement can also be reversed, with the force modulation flexure 84 and the SMA wire 2 connected at one end to the movable part 6, and the coupling flexure 83 connected at one end to the support structure 5.

[0075] Figure 2A A pair of integrally formed actuating units 80 is shown. Specifically, the main body portion 82, force adjustment flexure 84, coupling flexure 83, and movable mounting portion 86 of the pair of actuating units 80 can be integrally formed, i.e., formed from the same material. The main body portion 82, force adjustment flexure 84, coupling flexure 83, and movable mounting portion 86 of the pair of actuating units 80 can be formed (e.g., by etching) from a single sheet of metal. When assembled in the actuator assembly, the pair of actuating units 80 can be connected at the movable portion 6 (e.g., the movable mounting portion 86). The pair of actuating units 80 can extend substantially in a common plane.

[0076] Figure 2A The main body 82 of each actuation unit 80 includes two arms extending from a connection point 84m rearwardly toward the effective pivot point V to the force adjustment flexure 84. These two arms extend toward the force adjustment flexure 84. These two arms extend away from the SMA wire 2 and / or the coupling flexure 83. This allows the SMA wire 2 and / or the coupling flexure 83 to have an increased length compared to a case where the arms do not extend rearwardly. A longer SMA wire 2 can extend the stroke capabilities of the actuation unit 80. A longer coupling flexure 83 can reduce the lateral stiffness of the coupling flexure 83.

[0077] like Figure 3 As shown, the first example actuator assembly 10 comprises eight such actuating units 80 surrounding the movable part 6, instead of Figure 1A The eight SMA wires 2. The actuation unit 80 is arranged between the support structure 5 and the movable part 6 so as to drive the movement of the movable part 6 relative to the support structure 5 when selectively actuated.

[0078] Figure 3 The eight actuation units 80 of the actuator assembly 10 are arranged such that they are capable of moving the movable part 6 relative to the support structure 5 in three translational degrees of freedom (Tx, Ty, Tz) and two or three rotational degrees of freedom (Rx, Ry or Rx, Ry, Rz), as described with respect to FIG. Figure 1A Eight SMA wires 2 in a prior art actuator are described.

[0079] As discussed, the actuation unit 80 is arranged to apply an actuation force Fa to the movable part 6. The actuation force Fa (e.g., when visualized as a vector at a specific position in space) is arranged around the main axis P on each of the four sides of the actuator assembly 10 (i.e., the first side, the second side, the third side, and then the fourth side). Two actuation forces Fa are provided on each of the four sides. The two actuation forces Fa on each side are inclined in the same direction along the main axis P. The four sides extend in a ring around the main axis P. In this example, the sides are vertical and therefore form a square (when viewed along the main axis P), but alternatively, the sides can take a different shape, such as a quadrilateral. In this example, the forces are parallel to the outer surface of the square envelope of the movable part 6, but this is not required.

[0080] The first, second, third and fourth pairs of actuating units 80, 80 are arranged along a first, second, third and fourth sides of the actuator assembly 10, respectively, wherein the first and second sides are opposite sides through which a first axis x (also referred to herein as the x-axis) extends, and the third and fourth sides are opposite sides through which a second axis y (also referred to herein as the y-axis) extends.

[0081] Each actuating unit 80 of the first and second pairs of actuating units 80 is arranged to apply an actuating force Fa having a component in a first (e.g., upward) direction along the principal axis P. Each actuating unit 80 of the third and fourth pairs of actuating units 80 is arranged to apply an actuating force Fa having a component in a second, opposite (e.g., downward) direction along the principal axis P. The first and second pairs of actuating units 80 , 80 can be considered upside-down flipped versions of the third and fourth pairs of actuating units 80 , 80 .

[0082] Four actuation forces Fa form a "first" group having force components in one direction (the "upward" or "+z" direction) along the principal axis P, and the other four actuation forces Fa form a "second" group having components in the opposite direction (the "downward" or "-z" direction) along the principal axis P. In this document, "up" and "down" generally refer to opposite directions along the principal axis P.

[0083] The first pair of actuating units 80 and the second pair of actuating units 80 each include a first actuating unit 80 and a second actuating unit 80, the first actuating unit 80 being configured to apply an actuating force Fa having a force component in a first direction along the y-axis, and the second actuating unit 80 being configured to apply an actuating force Fa having a force component in a second, opposite direction along the y-axis. The third pair of actuating units 80 and the fourth pair of actuating units 80 each include a third actuating unit 80 and a fourth actuating unit 80, the third actuating unit 80 being configured to apply an actuating force Fa having a force component in a first direction along the x-axis, and the fourth actuating unit 80 being configured to apply an actuating force Fa having a force component in a second, opposite direction along the x-axis.

[0084] The first set of actuating forces Fa and the second set of actuating forces Fa are each arranged with two-fold rotational symmetry about the main axis P. In other words, the eight actuating units 80 are arranged with two-fold rotational symmetry about the main axis P. The first pair of actuating units 80 and the second pair of actuating units 80 are arranged with two-fold rotational symmetry about the main axis P. The third pair of actuating units 80 and the fourth pair of actuating units 80 are arranged with two-fold rotational symmetry about the main axis P.

[0085] As a result of this symmetrical arrangement, different combinations of actuation forces Fa can drive movement of the movable part 6 in multiple degrees of freedom, as described below.

[0086] The first set of actuation forces Fa, when generated together, drives upward movement, while the second set of actuation forces Fa, when generated together, drives downward movement.

[0087] When the actuation forces Fa of the first and second pairs of actuation units 80 are generated differently, tilting about the y-axis (i.e., Ry movement) can be driven. When the actuation forces Fa of the third and fourth pairs of actuation units 80 are generated differently, tilting about the x-axis (i.e., Rx movement) can be driven. Tilt in any arbitrary direction can be achieved as a linear combination of tilts about the two transverse axes x and y.

[0088] When the actuation forces Fa of the first actuation unit 80 and the actuation forces Fa of the second actuation unit 80 are generated differently, movement along the y-axis (i.e., Ty movement) can be driven. When the actuation forces Fa of the third actuation unit 80 and the actuation forces Fa of the fourth actuation unit 80 are generated differently, movement along the x-axis (i.e., Ty movement) can be driven. Movement in any arbitrary direction perpendicular to the primary axis P, z can be achieved as a linear combination of movement along the two transverse axes x, y. In some arrangements, a combination of four forces (including two forces from each group) when generated together drives movement along a transverse axis perpendicular to the primary axis z.

[0089] The first group of four actuation units 80 includes one actuation unit 80 from each of the first pair of actuation units 80, the second pair of actuation units 80, the third pair of actuation units 80, and the fourth pair of actuation units 80, and is configured to, when actuated together, drive the rotation of the movable part 6 relative to the support structure 5 about the main axis P in a first direction (e.g., drive a +Rz movement). The second group of four actuation units 80 (i.e., the remaining four actuation units 80) includes one actuation unit 80 from each of the first pair of actuation units 80, the second pair of actuation units 80, the third pair of actuation units 80, and the fourth pair of actuation units 80, and is configured to, when actuated together, drive the rotation of the movable part 6 relative to the support structure 5 about the main axis P in a second, opposite direction (e.g., drive a -Rz movement).

[0090] As mentioned above about Figure 1A As discussed above with respect to the actuator assembly 10 , the control circuitry may be electrically connected to the SMA wire 2 for supplying a drive current to the SMA wire 2 to drive these movements, for example, as described in WO 2011 / 104518 A1 (which is incorporated herein by reference to the maximum extent permitted by law).

[0091] When viewed in a direction perpendicular to the SMA wire 2 and / or the coupling flexure 83, Figure 2A The SMA wires 2 of a pair of actuator units 80 are crossed. Figure 2B As shown, the SMA wires 2 of a pair of actuation units may alternatively be arranged parallel or at least substantially parallel to each other.

[0092] Second Example of Actuator Assembly In the second example actuator assembly 10, Figure 3 The first pair of actuating units 80 and the second pair of actuating units 80 are each corresponding to Figure 4A The first pair of actuating units 80 and the second pair of actuating units 80 of the pair of actuating units shown are replaced, and Figure 3 The third pair of actuating units 80 and the fourth pair of actuating units 80 are each corresponding to Figure 4B The pair of actuator units shown (which are only Figure 4A The third pair of actuating units 80 and the fourth pair of actuating units 80 of the pair of actuating units are replaced by the upside-down flip type.

[0093] The second example actuator assembly 10 is identical to the first example actuator assembly 10 except for the following differences.

[0094] The coupling flexure 83 is connected to the corners of the movable part 6, rather than to the center portion of the movable part 6. In other words, each of the actuation units 80 is configured to apply the actuation force Fa to the corners of the movable part 6 (via the movable mounting portion 86), rather than to the center portion of the movable part 6 (via the movable mounting portion 86).

[0095] The ends 84 s of the force regulating flexures 84 are connected to a central portion of the support structure 5 rather than to a location adjacent to an edge of the support structure 5 .

[0096] Each of the first, second, third, and fourth pairs of actuation units 80 , 80 are configured to apply an actuation force Fa in a direction toward each other rather than in a direction away from each other.

[0097] The body portion 82 of the second example actuator assembly 10 does not include the two arms of the body portion 82 of the first example actuator assembly 10 .

[0098] Each pair of actuating units 80 is a discrete unit (ie, separate from each other), rather than the pair of actuating units 80 being integrally formed.

[0099] The second example actuator assembly 10 drives movement of the movable portion 6 relative to the support structure 5 in the same manner as the first example actuator assembly 10 .

[0100] Third Example of Actuator Assembly In the third example actuator assembly 10, as Figure 6 As shown, Figure 1A The eight SMA wires 2 of the actuator assembly 10 are connected on both sides. Figure 5AThe actuator unit 80 is replaced and is replaced on two different sides of the actuator assembly 10. Figure 5B The actuating unit 80 (which is only Figure 5A A pair of actuating units (upside down flip type) are replaced.

[0101] Figure 5A A pair of actuating units 80 and Figure 2A The pair of actuating units 80 are identical, except that one actuating unit 80 (the left actuating unit 80) is turned upside down. As described above, Figure 5B The pair of actuating units 80 are merely Figure 5A Thus, each pair of actuating units 80 of this third example is configured to apply an actuating force Fa that is offset from one another along the principal axis P. Furthermore, within each pair, the SMA wires 2 are parallel (or at least substantially parallel) to one another, and the coupling flexures are also parallel (or at least substantially parallel) to one another. Furthermore, within each pair, the coupling flexures 83 are connected to the top and bottom positions of the central mobile mounting portion 86 (or movable portion 6) (offset along the principal axis P), rather than being as in the example of FIG. Figure 2A The connections shown are to the same Z height (ie, the same height / position along the main axis P).

[0102] like Figure 6 As shown, the third example actuator assembly 10 includes eight such actuating units 80 surrounding the movable part 6, instead of Figure 1A The eight SMA wires 2. The actuation unit 80 is arranged between the support structure 5 and the movable part 6 so as to drive the movement of the movable part 6 relative to the support structure 5 when selectively actuated.

[0103] Figure 6 The eight actuation units 80 of the actuator assembly 10 are arranged such that they are capable of moving the movable part 6 relative to the support structure 5 in three translational degrees of freedom (Tx, Ty, Tz) and two or three rotational degrees of freedom (Rx, Ry or Rx, Ry, Rz), as described with respect to FIG. Figure 1A Eight SMA wires 2 in a prior art actuator are described.

[0104] As discussed, the actuation unit 80 is arranged to apply an actuation force Fa to the movable part 6. The actuation force Fa is arranged on each of the four sides of the actuator assembly 10 (i.e., the first side, the second side, the third side, and then the fourth side) around the main axis P. Two actuation forces Fa are provided on each of the four sides. The two actuation forces Fa on each side are inclined in opposite directions along the main axis P. The four sides extend in a ring around the main axis P. In this example, the sides are vertical and therefore form a square (when viewed along the main axis P), but alternatively, the sides can take a different shape, such as a quadrilateral. In this example, the forces are parallel to the outer surface of the square envelope of the movable part 6, but this is not required.

[0105] The first, second, third and fourth pairs of actuating units 80, 80 are arranged along a first, second, third and fourth sides of the actuator assembly 10, respectively, wherein the first and second sides are opposite sides through which a first axis x (also referred to herein as the x-axis) extends, and the third and fourth sides are opposite sides through which a second axis y (also referred to herein as the y-axis) extends.

[0106] The first pair of actuating units 80, the second pair of actuating units 80, the third pair of actuating units 80 and the fourth pair of actuating units 80 each include an actuating unit 80 configured to apply an actuating force Fa having a force component in a first (e.g., upward) direction along the main axis P and an actuating unit 80 configured to apply an actuating force Fa having a force component in a second, opposite (e.g., downward) direction along the main axis P.

[0107] In other words, the four actuation forces Fa (including one actuation force Fa on each of the side portions) form a "first" group having a force component in one direction (the "upward" or "+z" direction) along the main axis P, and the other four actuation forces Fa form a "second" group having a component in the opposite direction (the "downward" or "-z" direction) along the main axis P. In this document, "up" and "down" generally refer to opposite directions along the main axis P.

[0108] The first set of actuating forces Fa and the second set of actuating forces Fa are each arranged with two-fold rotational symmetry about the main axis P. The eight actuating units 80 are arranged with two-fold rotational symmetry about the main axis P. The first pair of actuating units 80 and the second pair of actuating units 80 are arranged with two-fold rotational symmetry about the main axis P. The third pair of actuating units 80 and the fourth pair of actuating units 80 are arranged with two-fold rotational symmetry about the main axis P.

[0109] As a result of this symmetrical arrangement, different combinations of actuation forces Fa can drive movement of the movable part 6 in multiple degrees of freedom, as described below.

[0110] The first set of actuation forces Fa, when generated together, drives upward movement, while the second set of actuation forces Fa, when generated together, drives downward movement.

[0111] The first pair of actuating units 80, when actuated together, is configured to apply a torque to the movable part 6 to drive the movable part 6 to rotate / tilt in a first direction about a first axis x relative to the support structure 5. The second pair of actuating units 80, when actuated together, is configured to apply a torque to the movable part 6 to drive the movable part 6 to rotate / tilt in a second, opposite direction about the first axis x relative to the support structure 5. The third pair of actuating units 80 is configured to apply a torque to the movable part 6 to drive the movable part 6 to rotate / tilt in a first direction about a second axis y relative to the support structure 5. The fourth pair of actuating units 80 is configured to apply a torque to the movable part 6 to drive the movable part 6 to rotate / tilt in a second, opposite direction about the second axis y relative to the support structure 5. Tilt in any arbitrary direction can be achieved as a linear combination of tilts about the two transverse axes x, y.

[0112] The first pair of actuating units 80 and the second pair of actuating units 80 each include a first actuating unit 80 and a second actuating unit 80, the first actuating unit 80 being configured to apply an actuating force Fa having a force component in a first direction along the y-axis, and the second actuating unit 80 being configured to apply an actuating force Fa having a force component in a second, opposite direction along the y-axis. The third pair of actuating units 80 and the fourth pair of actuating units 80 each include a third actuating unit 80 and a fourth actuating unit 80, the third actuating unit 80 being configured to apply an actuating force Fa having a force component in a first direction along the x-axis, and the fourth actuating unit 80 being configured to apply an actuating force Fa having a force component in a second, opposite direction along the x-axis.

[0113] When the actuation forces Fa of the first actuation unit 80 and the actuation forces Fa of the second actuation unit 80 are generated differently, movement along the y-axis (i.e., Ty movement) can be driven. When the actuation forces Fa of the third actuation unit 80 and the actuation forces Fa of the fourth actuation unit 80 are generated differently, movement along the x-axis (i.e., Ty movement) can be driven. Movement in any arbitrary direction perpendicular to the main axes P, z can be achieved as a linear combination of movements along the two transverse axes x, y.

[0114] The first group of four actuation units 80 includes one actuation force Fa from each of the first pair of actuation units 80, the second pair of actuation units 80, the third pair of actuation units 80, and the fourth pair of actuation units 80, and is configured to drive the rotation of the movable part 6 relative to the support structure 5 in a first direction about the main axis P (e.g., drive +Rz movement) when actuated together. The second group of four actuation units 80 (i.e., the remaining four actuation units 80) includes one actuation force Fa from each of the first pair of actuation units 80, the second pair of actuation units 80, the third pair of actuation units 80, and the fourth pair of actuation units 80, and is configured to drive the rotation of the movable part 6 relative to the support structure 5 in a second, opposite direction about the main axis P (e.g., drive -Rz movement) when actuated together.

[0115] As mentioned above about Figure 1A As discussed above with respect to the actuator assembly 10 , a control circuit may be electrically connected to the SMA wire 2 for supplying a drive current thereto to drive these movements, for example as described in WO 2011 / 104518 A1.

[0116] like Figure 7 As shown, one or more (or all) of the force modulating flexures 84 of the third example may be arranged to be in compression when the corresponding SMA wire 2 contracts, rather than being arranged to be in tension when the corresponding SMA wire 2 contracts.

[0117] like Figure 8 As shown, the coupling flexures 83 of each pair of actuating units 80 (i.e., the coupling flexures 83 of the first, second, third, and / or fourth pairs of actuating units 80 , 80 ) can intersect the primary axis P when viewed along either the first axis x or the second axis y. This can help reduce the XY footprint of the actuator assembly 10 . Alternatively, this can allow the coupling flexures 83 to be longer without affecting the XY footprint of the actuator assembly 10 , thereby achieving additional travel amplification for a given flexure design and line length. This can also bring the parallel coupling flexures 83 and line 2 closer together, which can help reduce any secondary torque generated by the flexure system.

[0118] Fourth Example of Actuator Assembly In the fourth example actuator assembly 10, Figure 6 The first pair of actuating units 80 and the second pair of actuating units 80 are each corresponding to Figure 9 The first pair of actuating units 80 and the second pair of actuating units 80 of the pair of actuating units shown in FIG. 8 are replaced, and Figure 6 The third pair of actuating units 80 and the fourth pair of actuating units 80 are each corresponding to Figure 9 The third pair of actuating units 80 and the fourth pair of actuating units 80 of the upside-down flip type (ie, the vertical flip type) are replaced.

[0119] The fourth example actuator assembly 10 is identical to the fourth example actuator assembly 10 except for the following differences.

[0120] The coupling flexures 83 are connected to the corners of the movable portion 6, rather than to the center portion of the movable portion 6. In other words, the actuation units 80 are each configured to apply the actuation force Fa to the corners of the movable portion 6 (via the movable mounting portion 86), rather than being configured to apply the actuation force Fa to the center portion of the movable portion 6 (via the movable mounting portion 86).

[0121] The ends 84 s of the force regulating flexures 84 are connected to a central portion of the support structure 5 rather than being connected adjacent to an edge of the support structure 5 .

[0122] Each of the first, second, third, and fourth pairs of actuation units 80 , 80 are configured to apply an actuation force Fa in a direction toward each other rather than in a direction away from each other.

[0123] Each of the first, second, third, and fourth pairs of actuation units 80 , 80 are configured to apply an input force Fi in a direction away from each other rather than in a direction toward each other.

[0124] The coupling flexures 83 of each pair of actuating units 80 are not parallel to each other, but are substantially parallel to each other. However, it should be understood that they may be parallel to each other.

[0125] Each pair of actuating units 80 is connected to each other via the end portion 84s for connection to the support structure 5, rather than being connected to each other via the mobile mounting portion 86. In other words, each of the first pair of actuating units 80, the second pair of actuating units 80, the third pair of actuating units 80, and the fourth pair of actuating units 80 shares a common end portion 84s for connection to the support structure 5, rather than sharing a common mobile mounting portion 86.

[0126] The fourth example actuator assembly 10 drives movement of the movable portion 6 relative to the support structure 5 in the same manner as the third example actuator assembly 10 .

[0127] Fifth Example of Actuator Assembly exist Figure 11 In the fifth example actuator assembly 10 shown, Figure 6 The first pair of actuating units 80 and the second pair of actuating units 80 are each corresponding to Figure 10The first pair of actuating units 80 and the second pair of actuating units 80 of the pair of actuating units shown in FIG. 8 are replaced, and Figure 6 The third pair of actuating units 80 and the fourth pair of actuating units 80 are each corresponding to Figure 10 The third pair of actuating units 80 and the fourth pair of actuating units 80 of the upside-down flip type (ie, the vertical flip type) are replaced.

[0128] The fifth example actuator assembly 10 is identical to the fourth example actuator assembly 10 except for the following differences.

[0129] The SMA wire 2 of the actuation unit 80 is arranged to extend perpendicularly to the main axis P, rather than being inclined in a direction along the main axis P.

[0130] The actuating units 80 of each pair are not integrally formed. In other words, the actuating units 80 of each pair are not connected to each other. More specifically, the end portions 84s of the force-adjusting flexures 84 of each pair of actuating units are not integrally formed. Instead, the actuating units 80 of each pair of actuating units 80 (i.e., each of the first, second, third, and fourth pairs of actuating units 80 , 80 ) are separate from each other, i.e., are discrete units.

[0131] The actuation unit 80 (eg, the body portion 82 and / or the force-adjusting flexure 84 ) intersects the primary axis P when viewed along the first axis x or the second axis y.

[0132] The body portion 82 does not include the two arms of the body portion 82 of the fourth example actuator assembly 10 .

[0133] Each of the first, second, third, and fourth pairs of actuation units 80 , 80 are configured to apply an input force Fi in a direction toward each other rather than in a direction away from each other.

[0134] The coupling flexures 83 of each pair of actuation units 80 are parallel to each other. However, it should be understood that they may not be parallel to each other (eg, may instead be substantially parallel to each other).

[0135] The fifth example actuator assembly 10 drives movement of the movable portion 6 relative to the support structure 5 in the same manner as the third example actuator assembly 10 .

[0136] Further details When viewed along the x-axis or y-axis, Figure 2B 、 Figure 5A 、 Figure 5B 、 Figure 6 、 Figure 7 、 Figure 8 、 Figure 9 、 Figure 10 and Figure 11 The SMA wires 2 of the actuator unit 80 do not cross / overlap each other. This can help reduce the problem of SMA wires 2 contacting and rubbing against each other, causing wear and tear of the wires 2. In addition, when viewed along the x-axis or y-axis, Figure 2B 、 Figure 8 、 Figure 9 、 Figure 10 and Figure 11 The SMA wire 2 of the actuation unit 80 also does not cross / overlap any other portion of the actuation unit 80 (e.g., does not cross / overlap the coupling flexure 83). This can help reduce the problem of the SMA wire 2 contacting and rubbing with other portions of the actuation unit 80, causing wear and tear of the wire 2.

[0137] Figure 4A 、 Figure 4B 、 Figure 10 and Figure 11 The actuating unit 80 can be easily mounted on the side during assembly of the actuating assembly 10 .

[0138] Figure 4A and Figure 4B The actuator unit 80 may have SMA wire 2, for a given XY footprint, with Figure 10 and Figure 11 Compared with the actuating unit 80 , the length of the SMA wire 2 is longer.

[0139] One or more coupling flexures 83 of the actuation unit 80 discussed herein may be tilted at an angle of 30 to 60 degrees, or more preferably 35 to 55 degrees, or most preferably 40 to 50 degrees relative to a plane perpendicular to the primary axis P. This may help ensure that the tilt achievable after the Rz movement is similar to the tilt achievable in Rx and Ry.

[0140] The third, fourth, and fifth examples of the actuator assembly 10 may provide better Rx, Ry, and / or Rz performance than the first and second examples of the actuator assembly 10. The first and second examples of the actuator assembly 10 may provide better Tx and Ty performance than the third, fourth, and fifth examples of the actuator assembly 10.

[0141] In the third, fourth, and fifth examples of the actuator assembly 10 , the x-axis may pass through the centers of the first and second pairs of actuating units 80 , and the y-axis may pass through the centers of the third and fourth pairs of actuating units 80 .

[0142] Support arrangement The above-described embodiments can be used to implement, among other things, 2-axis module tilt OIS or 3-axis module tilt OIS. In such embodiments, the actuation unit 80 is actuated to cause the movable portion 6 to rotate relative to the support structure 5 about any axis substantially perpendicular to the principal axis P (i.e., to cause Rx and Ry movement of the movable portion 6 relative to the support structure 5) and, optionally, to rotate about the principal axis P (i.e., to cause Rz movement of the movable portion 6 relative to the support structure 5). In such embodiments, the movable portion 6 may be supported (e.g., suspended) solely from the support structure 5 by the actuation unit 80. However, such embodiments may also include a support arrangement between the support structure 5 and the movable portion 6. The support arrangement can be configured to allow the movable portion 6 to rotate relative to the support structure 5 about any axis substantially perpendicular to the principal axis P and, optionally, about the principal axis P. The support arrangement can restrict other types of movement, such as translational movement of the movable portion 6 relative to the support structure 5, and thus can help improve the performance of the actuator assembly 10. The support arrangement can include, for example, one or more gimbals. The support arrangement may comprise, for example, a support arrangement equivalent to that described in WO 2021 / 209770 A1 (which document is incorporated herein by reference to the fullest extent permitted by law), see for example Figure 16 or Figure 17 of WO 2021 / 209770 A1.

[0143] Other variants It will be appreciated that many other variations of the above examples are possible.

[0144] although Figure 2A 、 Figure 2B 、 Figure 3 、 Figure 5A 、 Figure 5B 、 Figure 6 、 Figure 7 、 Figure 8 and Figure 9 The actuating units 80 of the pair are integrally formed, but this may not be the case. The actuating units 80 within each pair may alternatively be separate units. For example, Figure 2A 、 Figure 2B 、 Figure 3 、 Figure 5A 、 Figure 5B 、 Figure 6 、 Figure 7 and Figure 8 The actuating units 80 may not share a common mobile mounting portion 86, but may instead include separate mobile mounting portions 86. For example, Figure 9 The actuating units 80 may not share a common end 84s for connection to the support structure 5, but may instead include separate ends 84s for connection to the support structure 5 (e.g., as Figure 10 shown).

[0145] although Figure 4A 、 Figure 4B 、 Figure 10 and Figure 11 The actuating units 80 of are not formed integrally, but this may not be the case. Instead, the actuating units 80 within each pair may be formed integrally. For example, Figure 4A 、 Figure 4B 、 Figure 10 and Figure 11 The end portion 84s of the actuating unit 80 for connection to the support structure 5 may be formed integrally, for example, as Figure 9 shown.

[0146] The actuator assembly 10 may include a biasing arrangement configured to bias the movable portion 6 and the support structure 5 toward each other, for example, such that when the actuation unit 80 is unpowered, the movable portion 6 is biased into engagement with one or more end stops of the support structure 5. The actuator assembly 10 may include a biasing arrangement configured to bias the movable portion 6 toward a predetermined ("stored") position and / or orientation relative to the support structure 5 when the actuation unit 80 is unpowered. Examples of biasing arrangements that can be used with the actuator assembly 10 are described in WO 2021 / 005351 A1, which is incorporated herein by reference to the maximum extent permitted by law.

[0147] The actuator assembly 10 may include another ("AF" or "autofocus") actuator assembly configured to move one or more lenses of the lens assembly relative to the image sensor along an axis parallel to the optical axis of the one or more lenses (e.g., along the optical axis itself). The "AF" actuator assembly may be another type of SMA actuator assembly or may be a non-SMA actuator assembly, such as a voice coil motor (VCM) actuator assembly.

[0148] Although eight actuation units 80 are provided in the illustrated example, it will be appreciated that a different number of actuation units 80 may alternatively be provided.

[0149] As described above, although the actuator assembly 10 is described in conjunction with a camera, it should be understood that the actuator assembly 10 can be used in any device in which it is desired for the movable portion 20 to move relative to the support structure 10, for example, to provide tactile feedback in a tactile feedback device or to move an emitter or display in an augmented reality (AR) or virtual reality (VR) device.

[0150] SMA The actuation unit 80 described above includes at least one SMA wire, which may more generally be referred to as an SMA element. The term "shape memory alloy (SMA) element" may refer to any element comprising an SMA. An SMA element may have any shape suitable for the purposes described herein. An SMA element may be elongated and may have a circular cross-section or any other cross-section. The cross-section may vary along the length of the SMA element. An SMA element may have a relatively complex shape, such as a coil spring. It is also possible that the length of an SMA element (however defined) may be similar to one or more of its other dimensions. An SMA element may be in the form of a sheet, and such a sheet may be planar or non-planar. An SMA element may be pliable, or in other words, flexible. In some examples, when connected in a straight line between two components, an SMA element can only exert tension, forcing the two components together. In other examples, an SMA element may bend around a component and, when the SMA element tends to straighten under tension, may exert a force on the component. SMA elements can be beam-like or rigid and may be capable of applying different forces (e.g., non-tension) to the element. SMA elements may or may not include non-SMA materials and / or components. For example, an SMA element may include an SMA core and a coating of non-SMA material. Unless the context requires otherwise, the term "SMA element" may refer to any configuration of SMA material that acts as a single actuating element, e.g., one that can be individually controlled to generate a force acting on the element. For example, an SMA element may include two or more sections of SMA material mechanically arranged in parallel and / or in series. In some arrangements, an SMA element may be part of a larger SMA element. Such a larger SMA element may include two or more sections that can be individually controlled, thereby forming two or more SMA elements. SMA elements may include SMA wire, SMA foil, SMA film, or any other configuration of SMA material. SMA elements may be manufactured using any suitable method, such as by methods involving drawing, rolling, deposition, and / or other forming processes. The SMA element may exhibit any shape memory effect, such as a thermal shape memory effect or a magnetic shape memory effect, and may be controlled in any suitable manner, such as by Joule heating, another heating technique, or by applying a magnetic field.

Claims

1. An actuator assembly comprising: Part I; a second portion arranged to be movable relative to the first portion; eight actuation units arranged to move the second part relative to the first part upon actuation, wherein each actuation unit comprises: - Main body; - a force regulating flexure connected between said main body portion and said first portion; - a coupling flexure connected between said main portion and said second portion; - an SMA element arranged to exert an input force on the body portion upon actuation, thereby deforming the force-modulating flexure so as to modulate the input force and cause the coupling link to exert an actuation force on the second portion; The eight actuation units are arranged such that, upon selective actuation, they exert non-collinear forces on the second part relative to the first part, the non-collinear forces enabling the second part to move relative to the first part in up to six degrees of freedom.

2. The actuator assembly according to claim 1, wherein: The non-collinear force is capable of moving the second portion relative to the first portion in two or more rotational degrees of freedom or three translational degrees of freedom.

3. The actuator assembly according to any one of claims 1 or 2, wherein: In each actuation unit, the SMA element is connected between the body portion and the first portion.

4. An actuator assembly according to any one of the preceding claims, wherein: The eight actuation units are arranged into four pairs of actuation units, wherein each pair of actuation units is arranged on a different side of the second portion.

5. The actuator assembly according to claim 4, wherein: Each pair of actuation units comprises a respective first actuation unit and a respective second actuation unit, wherein for at least one pair of actuation units the arrangement of the second actuation unit corresponds to a reflection of the first actuation unit on a plane containing the main axis.

6. The actuator assembly according to claim 4 or 5, wherein: Each pair of actuation units comprises a respective first actuation unit and a respective second actuation unit, wherein for at least one pair of actuation units the arrangement of the second actuation unit corresponds to a reflection of the first actuation unit both in a plane containing the main axis and in a plane substantially perpendicular to the main axis.

7. An actuator assembly according to any one of claims 4 to 6, wherein: For at least one pair of actuating units, the coupling flexure of one actuating unit is connected to the side of the second part at or near one longitudinal end of the side of the second part, and the coupling flexure of the other actuating unit of the pair of actuating units is connected to the side of the second part at or near the other longitudinal end of the side of the second part.

8. An actuator assembly according to any one of claims 4 to 7, wherein: For at least one pair of actuation units, the force regulating flexure of each actuation unit of the pair of actuation units is connected to a central portion of a side of the first part, optionally wherein the force regulating flexure is connected to the side at a point that is greater than 25% of the distance along the side and less than 75% of the distance along the side.

9. An actuator assembly according to any one of claims 4 to 8, wherein: For at least one pair of actuation units, the force adjustment element of each actuation unit of the pair of actuation units is arranged to be placed under compression by the respective body portion when the respective SMA element exerts an input force on the respective body portion.

10. An actuator assembly according to any one of the preceding claims, wherein: The coupling flexure, the SMA element, and the force modulation flexure each extend from the body portion in a direction at least partially toward a same longitudinal end of a side portion.

11. The actuator assembly of claim 4, wherein: In each actuation unit, the coupling flexure is connected to a central portion of a side of the second portion, optionally wherein the coupling flexure is connected to the side at a point greater than 25% of the distance along the side and less than 75% of the distance along the side.

12. The actuator assembly according to claim 4 or 5, wherein: In each pair of actuating units, the force regulating flexure of one actuating unit is connected to the side of the first part at or near one longitudinal end of the side of the first part, and the force regulating flexure of the other actuating unit is connected to the side at or near the other longitudinal end of the side.

13. An actuator assembly according to any one of claims 4 to 6, wherein: In each pair of actuating units, the coupling link of one actuating unit extends from the main body portion to the second portion in a direction at least partially toward one longitudinal end of the side portion, and the coupling link of the other actuating unit extends from the main body portion to the second portion in a direction at least partially toward the other longitudinal end of the side portion.

14. The actuator assembly of claim 13, wherein: The connection point between the coupling link and the second portion of each actuating unit is located closer to an opposite longitudinal end of the side portion than to the longitudinal end of the side portion at which the corresponding body portion is arranged.

15. An actuator assembly according to claim 4, 11, 12 or 13 when dependent on claim 3, wherein In each actuation unit, the coupling link extends from the body portion to the second portion in a direction at least partially toward a longitudinal end of the side portion, and the SMA element extends from the body portion to the first portion in a direction at least partially toward the same longitudinal end of the side portion.

16. An actuator assembly according to any one of claims 4 to 15, wherein: The SMA elements of each pair of actuation units are crossed when viewed perpendicularly to the side on which the actuation units of each pair are arranged.

17. An actuator assembly according to any one of claims 4 to 16, wherein: The SMA elements of each pair of actuation units do not cross when viewed perpendicular to the side on which each pair of actuation units is arranged, optionally wherein the SMA elements of each pair of actuation units are parallel.

18. An actuator assembly according to any one of the preceding claims, wherein: The body portion, the force adjustment flexure and the coupling flexure of each pair of actuating units are integrally formed.

19. An actuator assembly according to claim 3 or any one of claims 4 to 18 when dependent on claim 3, wherein The main body portion of each actuation unit includes a first arm and / or a second arm, wherein the first arm extends between a connection point to the force modulation flexure and a connection point to the SMA wire, and the second arm extends between the connection point to the force modulation flexure and a connection point to the coupling flexure.

20. The actuator assembly of claim 19, wherein: The first arm extends away from an end of the SMA wire connected to the first portion, and / or wherein the second arm extends away from an end of the coupling flexure connected to the second portion.

21. An actuator assembly according to claim 19 or 20 when dependent on claim 15, wherein In each actuation unit, the first arm and / or the second arm extends away from the connection point to the force regulating flexure in a direction at least partially towards the other longitudinal end of the side portion.

22. An actuator assembly according to claim 19 or 20 when dependent on claim 15, wherein In each actuation unit, the first arm and / or the second arm extends away from the connection point to the force regulating flexure in a direction at least partially towards the same longitudinal end of the side portion.

23. An actuator assembly according to any one of the preceding claims, wherein: Each actuation unit is configured such that the force modulating flexure amplifies an amount of actuation of the SMA wire into a relatively greater amount of movement of the second portion relative to the first portion.

24. A camera assembly comprising: An actuator assembly according to any one of claims 1 to 23; one or more lenses included in one of the first portion and the second portion of the actuator assembly; and an image sensor included in the other of the first and second portions of the actuator assembly; Wherein the actuator assembly is configured to move the one or more lenses and the image sensor relative to each other in three translational degrees of freedom.

25. A camera assembly comprising: An actuator assembly according to any one of claims 1 to 23; and a support structure comprising one of the first portion and the second portion of the actuator assembly; a module included in the other of the first portion and the second portion of the actuator assembly, wherein the module includes an image sensor and one or more lenses; Wherein the actuator assembly is configured to rotate the module relative to the support structure in two or more rotational degrees of freedom.

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