actuator assembly

Abstract

An actuator assembly includes: a base (30); a rotatable component (20) rotatable relative to the base about a main axis O; and one or more actuation units (10), each actuation unit configured to apply an actuating force capable of rotating the rotatable component relative to the base about the main axis. Each actuation unit includes: a body portion (14); a shape memory alloy SMA element (11) connected between the body portion and one of the base and the rotatable component, and configured to apply an input force to the body portion when the actuation unit is actuated; a force adjustment element (12) connected to the body portion and one of the base and the rotatable component, and configured to adjust the input force to generate an actuating force; and a connecting element (15) connecting the body portion to the other of the base and the rotatable component, and capable of transmitting the actuating force to the other of the base and the rotatable component.

Description

[0001] field This application relates to an actuator assembly. According to some embodiments, the actuator assembly includes a rotary actuator assembly, such as a variable aperture assembly.

[0002] background There are various devices that are intended to provide control over movable elements. SMA elements, such as SMA lines, may be advantageous as actuators in such devices, for example, because the high energy density of SMA lines means that the SMA actuator required to apply a given force to the movable element can be relatively small.

[0003] One type of device known to use SMA lines as actuators is a miniature camera, such as a miniature camera for a smartphone or other portable electronic device. WO2011 / 104518 discloses an example of an SMA actuation device suitable for a miniature camera.

[0004] A variable aperture assembly within a camera can use SMA elements (e.g., SMA lines) to move blades in order to adjust the size of the variable aperture. An example of such a variable aperture assembly is disclosed in WO2024 / 057042: the variable aperture assembly includes a base, a rotatable component, and an actuator assembly configured to drive the rotatable component to rotate relative to the base about a main axis to any rotational position within a range of motion. The actuator assembly includes at least one SMA element coupled between the base and the rotatable component. A plurality of blades are connected to the base and the rotatable component. Rotation of the rotatable component drives rotation of each of the plurality of blades to change the size of the variable aperture.

[0005] When an SMA element is actuated, the blade ideally moves a relatively large distance to provide a relatively large range of variable aperture sizes. This relatively large movement of the blade can be achieved through a relatively large rotation of the rotatable component; however, this may be difficult to achieve using a single SMA element directly coupled between the base and the rotatable component.

[0006] Overview According to one aspect of the invention, an actuator assembly is provided, comprising: a base; a rotatable member rotatable relative to the base about a main axis; and one or more actuation units, each actuation unit configured to apply an actuating force capable of rotating the rotatable member relative to the base about the main axis. Each actuation unit includes: a body portion; a shape memory alloy SMA element connected between the body portion and one of the base and the rotatable member, and configured to apply an input force to the body portion when the actuation unit is actuated; a force-modifying element connected to the body portion and one of the base and the rotatable member, and configured such that the input force is modulated to generate an actuating force; and a connecting element connecting the body portion to the other of the base and the rotatable member, and capable of transmitting the actuating force to the other of the base and the rotatable member.

[0007] In some embodiments, the actuation unit is configured to amplify the change in actuation amount of the SMA element to a relatively large amount of movement of the portion of the coupling element connected to the base and the other of the rotatable components. In an alternative embodiment, the actuation unit is configured to amplify the magnitude of the input force to a relatively large magnitude of the actuation force.

[0008] The change in the actuation amount of an SMA element can also be referred to as the stroke of the SMA element. Compared to actuator assemblies where the SMA element is directly connected between the rotatable component and the base, providing an actuation unit to amplify the stroke of the SMA element can result in an increase in the rotation of the rotatable component relative to the base. This increase in rotation can be desirable in various actuator assemblies. For example, when used as part of a variable aperture assembly, the increase in rotation can extend the range of motion of the blades in the variable aperture assembly, thereby increasing the range of variable aperture sizes that the variable aperture assembly can achieve. Alternatively, providing an actuation unit to amplify the input force can allow for more reliable rotation of a heavier rotatable component or allow for more accurate positioning of the rotatable component relative to the base.

[0009] The input force is provided by the SMA element, such as tension within the SMA element. The SMA element can be elongated. The SMA element can be an SMA line. The actuation amount of the SMA element can be the change in length of the SMA element when it is actuated. The actuation of the SMA element can be the contraction of the SMA element. The portion of the connecting element that is connected to the other of the base and the rotatable component can be equivalent to the portion of the other of the base and the rotatable component that is connected to the connecting element, and corresponds to the location where a force is applied to the other of the base and the rotatable component through the connecting element.

[0010] In its most general sense, the present invention relates to an actuator assembly (rotary actuator assembly) that provides relative rotational motion between two components. A variable aperture assembly is a specific example of such a rotary actuator assembly, and most of the following description specifically relates to a variable aperture assembly. However, unless the context otherwise requires, the features described in connection with embodiments of a variable aperture assembly should be considered to be more generally applicable to rotary actuator assemblies.

[0011] In some embodiments, when viewed along the main axis, the angle range of the body portion around the main axis is at least 60° or at least 90°. Alternatively, the angle range of the body portion may be at least 45°, at least 80°, or at least 135°. Therefore, the body portion can be relatively large, allowing the space around the actuator assembly to be used effectively to improve the stroke amplification of the actuator unit.

[0012] In some embodiments, when viewed along the main axis, the SMA element, body portion, and connecting element extend in a circle around the main axis. The SMA element, body portion, and connecting element may be arranged in series to surround the main axis. When viewed radially outward from the main axis, a large portion (i.e., at least 50%, optionally at least 75%, or at least 90%) of the SMA element, body portion, and connecting element may not overlap. The combined angle range of the main axis around the combination of SMA element, body portion, and connecting element may be at least 90°, preferably at least 150°, at least 180°, or at least 300°. Therefore, the space around the variable aperture assembly can be used effectively, and the size of the actuation unit in the direction radially away from the main axis can be reduced.

[0013] Some embodiments include two actuation units configured to rotate the rotatable component relative to the base about a main axis in opposite directions upon actuation. A first actuation unit may be configured to rotate the rotatable component relative to the base about the main axis in a first direction upon actuation, and a second actuation unit may be configured to rotate the rotatable component relative to the base about the main axis in a second direction upon actuation, wherein the second direction is opposite to the first direction. Therefore, the response time and accuracy of rotational positioning can be improved. The two actuation units, particularly the main body and optional SMA elements, force adjustment elements, and / or connecting elements, may be geometrically congruent. The two actuation units may be arranged mirror-symmetrically about an axis orthogonal to the main axis, or doubly rotationally symmetric about the main axis. Alternatively, a single actuation unit may be provided, which is resisted by a biasing force, for example, due to a spring or other elastic element.

[0014] In some embodiments, the SMA elements of the two actuation units are substantially parallel to each other and arranged on opposite sides of the main axis. The SMA elements of the two actuation units may be substantially equidistant from the main axis. Therefore, when the SMA elements are actuated, the space around the main axis can be heated in a uniform manner, which is typically generated by the heating of the SMA elements. This uniform heating can be used in various applications, such as to avoid asymmetric effects on optical elements that may be positioned in the space adjacent to the main axis. The SMA elements can be substantially parallel because the angle between the nominal lines along the length of the SMA elements can be less than 10°, for example less than 5°.

[0015] In some embodiments, the first actuation unit of the two actuation units is configured such that a corresponding SMA element is connected between the main body and the base, a corresponding force adjustment element is connected between the main body and the base, and a corresponding coupling element is connected between the main body and the rotatable component; and the second actuation unit of the two actuation units is configured such that a corresponding SMA element is connected between the main body and the rotatable component, a corresponding force adjustment element is connected between the main body and the rotatable component, and a corresponding coupling element is connected between the main body and the base. This alternative mounting of the actuation units allows the arrangement of the actuation units to be more variably adapted to a desired layout.

[0016] In some embodiments, the two actuation units are configured not to overlap when viewed along the main axis. When viewed perpendicular to the main axis, the two actuation units may overlap. Avoiding overlap when viewed along the main axis can be achieved by alternative mounting of the actuation units, particularly when a relatively large body portion or actuation unit is provided surrounding the main axis.

[0017] In some embodiments, the main body portions of the two actuation units are directly connected to each other or integrally formed. Therefore, actuation of the SMA element of one actuation unit can move the main body portions of both actuation units, thereby applying actuating force to the base and the other rotatable component via a connecting element of the two actuation units. This reduces the risk of unintentional deformation of one connecting element without causing rotation of the rotatable component. The two connecting elements can be configured such that when one SMA element is actuated, one connecting element is in a tensioned state (thus pulling the rotatable component), while the other connecting element is in a compressed state (thus pushing the rotatable component).

[0018] In some embodiments, when viewed along the main axis, one or more actuation units are configured to completely overlap with the minimum square and / or minimum circle surrounding the base and the rotatable component. Therefore, the arrangement of the actuation units may not increase the coverage area of ​​the actuator assembly when viewed along the main axis, allowing for a compact actuator assembly.

[0019] In some embodiments, i) the nominal lines of the forces applied to the body portion by the SMA elements, ii) the nominal lines of the forces applied to the body portion by the connecting elements, and iii) the nominal lines of the forces applied to the body portion by the force adjusting elements are concurrent lines. In particular, the nominal lines can be concurrent when the body portion is in a specific position relative to the base and / or relative to the rotatable component. A specific position can be the initial position of the body portion, for example, when the rotatable component is at the center of its rotational position range relative to the base. A specific position can be the position when the SMA elements of both actuating units are actuated equally and / or when any flexure does not flex and therefore does not deform. Providing forces on concurrent lines ensures that the body portion is in a balanced state, thereby reducing the risk of the body portion rotating about the force adjusting elements and / or connecting elements (when such rotation is not required).

[0020] In some embodiments, the force adjustment element is configured to guide rotation of the body portion relative to one of the base and the rotatable component when the SMA element is actuated. The force adjustment element may define a pivot axis about which the body portion may rotate. The pivot axis may be an effective pivot axis whose position can change depending on the load and position on the body portion, or it may be a physical pivot axis that is fixedly positioned relative to the body portion and one of the body portion and the rotatable component.

[0021] In some embodiments, the force adjustment element includes a force adjustment flexure configured to flex upon actuation of the SMA element, thereby guiding the body portion to rotate about an effective pivot axis relative to one of the base and the rotatable component. The force adjustment flexure may be elongated. It may be rigid along its length and flexible in a direction orthogonal to its length. The force adjustment flexure is configured to be in a tensioned state upon actuation of the SMA element.

[0022] In some embodiments, the force adjustment element includes a rotary support configured to guide the body portion to rotate about a pivot axis relative to one of the base and the rotatable component. The rotary support may be pin-engaged, for example, comprising a pin located on one of the body portion and the base and the rotatable component, the pin engaging a support surface, such as the inner surface of a hole, on the other of the body portion and the base and the rotatable component. The rotary support may provide a pivot axis having a fixed position relative to the body portion and one of the base and the rotatable component.

[0023] In some embodiments, the force adjustment element includes a support device configured to guide translational movement of the main body portion relative to one of the base and the rotatable component along a movement axis, wherein the movement axis is at an angle to the direction of the input force. The angle between the movement axis and the input force can be in the range of 45° to 90°, preferably in the range of 60° to 85°. The support device may include a first support surface on the main body portion and a second support surface on one of the base and the rotatable component. The first and second support surfaces may translate relative to each other, either by sliding directly on each other or by providing a rolling support element disposed between the first and second support surfaces and rolling along the first and second support surfaces during relative movement. The SMA element may be configured to load the support device upon actuation. Thus, the SMA element may press the first and second support surfaces together.

[0024] In some embodiments, the connecting element allows relative movement between the body portion and another of the base and the rotatable component in a direction orthogonal to the actuation force. The connecting element may also be referred to as a connecting link. The connecting element can allow the body portion to rotate relative to the other of the base and the rotatable component.

[0025] In some embodiments, the connecting element includes a connecting flexure that connects the main body portion to another of the base and the rotatable component. The connecting flexure may be elongated. The connecting flexure may be rigid along its length and compliant in a direction orthogonal to its length.

[0026] In some embodiments, the main body, connecting elements, and / or force adjustment elements are integrally formed. Therefore, the relative positioning of these components can be reliably predetermined and is independent of any assembly of these components.

[0027] In some embodiments, the coupling element includes a coupling support comprising a first support surface on the main body portion, a second support surface on the other of the main body and the rotatable component, and a support element between the first and second support surfaces. Alternatively, the first and second support surfaces may be slidably engaged with each other, thereby omitting the support element. The first and second support surfaces may transmit actuating forces to the other of the base and the rotatable component.

[0028] In some embodiments, each actuation unit is configured such that the corresponding coupling element is arranged closer to the main axis than the corresponding SMA element. Therefore, the SMA element can be positioned away from the main axis, thereby reducing heating of the space around the main axis due to actuation of the SMA element. It also reduces the risk of the SMA element inadvertently entering the space around the main axis when in a de-energized or relaxed state, which could be undesirable.

[0029] In some embodiments, the actuator assembly further includes a pair of friction surfaces that abut against each other by a biasing force, thereby generating static friction between the pair of friction surfaces to maintain the position of the rotatable component relative to the base when at least one actuation unit is not actuated.

[0030] In an embodiment, the variable aperture assembly includes one or more pairs of friction surfaces, each pair including a first friction surface and a second friction surface. The first and second friction surfaces are biased against each other by a normal force, thereby generating static friction between the first and second friction surfaces when the actuator is not actuated, for maintaining the position of the blade.

[0031] Static friction is used to maintain the orientation of the rotating component and, optionally, the position of the blades, and is therefore intentionally chosen to be large enough to allow for position holding. Thus, unlike conventional actuator assemblies, no frictional force is minimized. Static friction can be used to hold the position when the acceleration of the actuator assembly is below a holding threshold. The holding threshold may be greater than the acceleration due to gravity, and therefore greater than g (9.81 m / s²), preferably greater than 2 g, greater than 5 g, or greater than 10 g.

[0032] In some embodiments, at least one actuating unit is arranged such that the biasing force between a pair of friction surfaces decreases when the actuating unit is actuated, thereby reducing the static friction between the pair of friction surfaces. When the actuating unit is actuated, the normal force between at least one pair of friction surfaces can decrease, thereby reducing the static friction between the pair of friction surfaces. This reduction in friction ensures that the actuating unit can reliably rotate rotatable components or move blades and set the size of variable apertures. The static friction between the friction surfaces can be set higher compared to the case where the static friction remains constant.

[0033] In some embodiments, at least one actuating unit is arranged such that at least one pair of friction surfaces disengage when at least one actuating unit is actuated. Therefore, the frictional force between the friction surfaces can be reduced to zero, thereby minimizing the motion resistance when at least one actuating unit is actuated.

[0034] In some embodiments, the normal force biasing at least one pair of friction surfaces acts in a direction perpendicular to the principal axis. The normal force may extend transversely to the principal axis. The friction surfaces may be substantially parallel to the principal axis.

[0035] Some embodiments include one or more biasing devices arranged to bias pairs of friction surfaces using a bias (normal) force, thereby generating friction. At least one biasing device may include an elastic element, such as a spring (coil spring, flexure, leaf spring) or an elastic element (rubber band, etc.). At least one biasing device may include a magnetic element. For example, the biasing device may include a magnet on one component of the variable aperture assembly (such as a base, rotatable component) and a magnet or ferromagnetic material on another component of the variable aperture assembly.

[0036] Some embodiments include a support device that guides the rotation of the rotatable component relative to the base about a main axis. The support device may include, for example, a planar or sliding support, a rolling support, or a flexural support. At least one actuating unit may be configured to drive the rotatable component to any rotational position within its range of motion relative to the base about the main axis.

[0037] In some embodiments, the base is disposed within a hole extending along the main axis through the rotatable component, and / or the rotatable component is disposed within a hole extending along the main axis through the base. The base and the rotatable component may be concentric rings. The rotatable component may be an inner ring, and the base may be an outer ring.

[0038] According to another aspect of the invention, a variable aperture assembly is provided, the variable aperture assembly including an actuator assembly and a plurality of blades configured such that rotation of a rotatable component relative to a base causes movement of the blades, thereby changing the size of the variable aperture.

[0039] In some embodiments, each of the plurality of blades is connected between the base and the rotatable component. Each blade is connected to the base via a first set of complementary connection features, and each blade is connected to the rotatable component via a second set of complementary connection features.

[0040] According to another aspect of this invention, a camera is provided, comprising: a variable aperture assembly; a lens assembly; and an image capturing device; wherein the optical axis of the lens assembly coincides with the principal axis, such that light passing through the variable aperture assembly is focused by the lens and received by the image capturing device. For example, the camera could be a miniature camera for integration into portable or wearable electronic devices.

[0041] In some embodiments, the variable aperture assembly is mounted on the lens assembly such that the lens assembly is received within a hole in a base or rotatable component aligned with the main axis. A portion of the variable aperture assembly (such as more than 50%, 60%, 70%, 80%, or 90%) may overlap with the lens assembly along the main axis.

[0042] According to another aspect of the invention, an electronic device incorporating a camera is provided. For example, the electronic device may be a portable or wearable electronic device, such as a smartphone. Brief description of the attached diagram Some embodiments of the invention will now be described by way of example only with reference to the accompanying drawings, in which: Figure 1 It is a schematic plan view of a variable aperture assembly with a relatively closed variable aperture; Figure 2 It is a schematic plan view of a variable aperture assembly with a relatively open variable aperture; Figure 3 This is a schematic side view of a variable aperture assembly assembled on a lens assembly; Figure 4 This is a schematic plan view of the arrangement of SMA elements used to adjust the variable aperture; Figure 5A and Figure 5B These are perspective views and plan views of the actuation unit, which forms part of the actuator assembly, and Figure 5C This is a plan view of another such actuation unit; Figure 6 It is a schematic plan view of a variable aperture assembly with an actuation unit for stroke amplification; Figure 7 It is a schematic plan view of another variable aperture assembly with an actuation unit for stroke amplification, which has an alternative arrangement of SMA elements and connecting elements; Figure 8A and Figure 8B This is a schematic plan view of a variable aperture assembly with an actuation unit having a relatively large main body portion; Figure 9A It is a schematic plan view of a variable aperture assembly with alternately installed actuator units, and Figure 9B and Figure 9C An alternative arrangement of alternately installed actuator units is shown; Figure 10A and Figure 10B This is a schematic plan view of a variable aperture assembly with an actuation unit having a force adjustment element in the form of a translational support. Figure 11A and Figure 11B It is a schematic plan view of a variable aperture assembly with an actuation unit having a connected main body portion; Figure 12 It is a schematic plan view of a variable aperture assembly with an actuation unit having a connecting element in the form of a connecting support; Figure 13This is a schematic plan view of a variable aperture assembly with another type of actuation unit; and Figure 14A yes Figure 10A A schematic plan view of a variable aperture assembly, but with different connecting elements, and Figure 14B yes Figure 14A Detailed view of the connecting elements.

[0044] Detailed description Certain example devices will now be described. Where similar or identical components are used in different examples, these similar or identical components will be given the same reference numerals. For efficiency, the description of similar or identical elements may not be repeated between examples, and the characteristics and features of the elements should be understood to apply to those elements in all embodiments, unless otherwise indicated in the description.

[0045] The following description and accompanying drawings present different embodiments of a variable aperture assembly or a portion thereof. As previously stated, unless the context otherwise requires, these should be considered as examples of actuator assemblies (rotary actuator assemblies) that provide relative rotational motion between a base and a rotatable component. The features presented in conjunction with the variable aperture assembly should be considered more generally applicable to any rotary actuator assembly.

[0046] Furthermore, in the following description, the terms "actuator" and "actuation unit" are used broadly and synonymously to refer to the portion of the actuator assembly that provides driving force to achieve relative rotational motion. The presented embodiments particularly relate to an actuation unit comprising one or more shape memory alloy (SMA) elements. This can be an SMA line, and where the term SMA line is used, this should be considered to include other suitable forms of SMA elements. Actuation of the actuation unit is achieved by causing the SMA elements to contract by heating them (e.g., by passing an electric current through them).

[0047] Figures 1 to 3 The variable aperture assembly 1 is schematically depicted. Figure 1 A plan view of a variable aperture assembly 1 with a relatively small variable aperture is shown, and Figure 2 A plan view of a variable aperture assembly 1 with a relatively large variable aperture is shown. Figure 3 A side view of the variable aperture assembly 1 combined with the lens assembly 50 is shown.

[0048] The variable aperture assembly includes a base 30 and a rotatable component 20. The rotatable component 20 is rotatable relative to the base 30, particularly about a main axis O. The base 30 is shown as being disposed generally around the rotatable component 20 (although they may partially overlap in a radial direction perpendicular to the main axis). Alternatively, the rotatable component 20 may surround the base 30. At least one of the base 30 and the rotatable component 20 defines an aperture allowing light or fluid (e.g., gas or liquid) to pass through. The aperture surrounds the main axis O. The aperture may have rotational symmetry about the main axis O. The base 30 and the rotatable component 20 are generally formed as a loop around the main axis O, through which light can pass, particularly reaching objects such as... Figure 3 The lens assembly 50 shown.

[0049] The base 30 can be fixed within a larger device (such as a smartphone or other portable electronic device) in which the variable aperture assembly 1 is incorporated. The base 30 can be fixed, for example, relative to a lens element of a lens assembly 50 provided in combination with the variable aperture assembly 1. However, the base 30 can also typically be movable within such a larger device. Unless otherwise explicitly stated, the base 30 is used herein as a reference structure relative to which the movement of other components is described. The base 30 may include multiple components fixed relative to each other to form the base 30.

[0050] The variable aperture assembly 1 may include a support device between the rotatable component 20 and the base 30. Figures 1 to 3 (Not shown in the image). The support device can guide the rotation of the rotatable component 20 relative to the base 30. The support device can constrain one or more degrees of freedom of movement other than rotation. For example, the support device can constrain the movement of the rotatable component 20 relative to the base 30 along the main axis O. The support device can include rolling supports (such as roller or ball supports), planar supports (e.g., sliding supports), or flexural supports (e.g., flexural arrangements that constrain degrees of freedom of movement). The variable aperture assembly 1 may also include a biasing device (not shown), such as a flexural or other type of spring arrangement, for loading the support device.

[0051] The variable aperture assembly 1 also includes a plurality of blades 40. The blades 40 may also be referred to as leaflets 40. The plurality of blades 40 define a variable aperture. The variable aperture is preferably substantially circular, but may generally have other shapes depending on the desired application of the variable aperture assembly 1. Each blade 40 is coupled between the base 30 and the rotatable member 20 in such a way that the size of the variable aperture changes with rotation of the rotatable member 20 relative to the base 30.

[0052] exist Figure 1 and Figure 2In one embodiment, each blade 40 is coupled to the base 30 via a respective pin 33 and to the rotatable member 20 via a respective pin 23. Rotation of the rotatable member 20 relative to the base 30 causes relative movement of the pins 23, 33, thereby allowing the blade 40 to effectively pivot about the pins 23, 33 to change the variable aperture. The distance between the pins 23, 33 will change during rotation of the rotatable member 20, and therefore in the depicted embodiment, each blade 40 is received by at least one pin in an elongated hole or slot formed in the blade 40 to accommodate this change and coupled to its corresponding pin 23, 33. As shown, the pin 33 formed on the base 30 engages a slot extending to the edge of the blade 40. In an alternative embodiment not shown, the pins 23, 33 are spring-loaded relative to each other by a flexure coupled to the base 30 or the rotatable member 20 (or both pins 23, 33 may be flexibly coupled), thereby allowing each pin 23 to move along a circular path around the corresponding pin 32 as the rotatable member 20 rotates. In another alternative, a pin may be provided on the blade 40 and engage a hole or slot formed in the base 30 and the rotatable component 20. Typically, the connection between the blade 40 and the base 30 and the rotatable component 20 may include any mechanism that allows the blade 40 to move as the rotatable component 20 rotates to adjust the variable aperture.

[0053] exist Figure 1 and Figure 2 In this embodiment, the variable aperture assembly 1 comprises a total of six blades 40. The blades 40 are stacked in two layers, with three blades 40 in each layer, one layer on top of the other. When viewed along the main axis O, the two layers overlap. However, typically, the variable aperture assembly 1 may include any number of blades 40 arranged in any number of layers.

[0054] The variable aperture assembly 1 also includes one or more actuation units 10, in Figure 3 The diagram is schematically shown. Each actuation unit 10 is configured to drive the rotatable component 20 to rotate relative to the base 30 about the main axis O. One or more actuation units 10 can rotate the rotatable component 20 relative to the base 30 to any rotational position within the range of motion. Therefore, the size of the variable aperture defined by the blade 40 can be adjusted to any size within a continuous range.

[0055] Figure 3The combination of the variable aperture assembly 1 and the lens assembly 50 is shown. The base 30 of the variable aperture assembly 1 can be mounted on the lens assembly 50 such that the lens assembly 50 is nested or disposed within a through-hole or opening in the base 30 and the rotatable component 20, the through-hole or opening extending along the main axis O of the variable aperture assembly 1. The main axis O can coincide with the optical axis of the lens assembly 50. The variable aperture assembly 1 can therefore adjust the amount of light entering the lens assembly 50. Light enters the lens assembly 50 along optical path 2. Between the variable aperture assembly 1 and the lens assembly 50, the optical path 2 can be shaped as a cone around the main axis O.

[0056] SMA drive unit Figure 4 A variable aperture assembly 1 with two actuation units 10 is schematically shown. Blades 40 are not shown, but it is evident that blades 40 can be combined with the above. Figure 1 and Figure 2 It is connected to the base 30 and the rotatable component in the same manner as described. Figure 4 Each actuation unit 10 of the variable aperture assembly 1 shown includes a corresponding SMA line 11. Each SMA line 11, and thus each actuation unit 10, is configured to drive the rotatable member 20 to rotate about the main axis O relative to the base 30 upon actuation. In some embodiments, the SMA line 11 drives the rotatable member 20 to any rotational position within a range of motion relative to the base. In some other embodiments, the SMA line 11 drives the rotatable member 20 to a predetermined set of positions within a range of motion relative to the base. This adjusts the size of the variable aperture.

[0057] SMA wire 11 is connected between base 30 and rotatable component 20 via connecting elements 42 and 43. For example, connecting elements 42 and 43 can be crimped elements. As shown, SMA wire 11 can be directly connected between base 30 and rotatable component 20, such that connecting elements 42 and 43 are directly connected to base 30 and rotatable component 20. Alternatively, intermediate elements ( Figure 4 (Not shown) can be connected between connecting elements 42, 43 and base 30 and / or rotatable component 20, such that SMA line 11 is indirectly connected between base 30 and rotatable component 20. This intermediate element transmits the force in SMA line 11 to rotatable component 20 to enable rotation of rotatable component 20 relative to base 30.

[0058] like Figure 4As shown, the variable aperture assembly 1 may include two actuation units 10, each actuation unit including a corresponding SMA line 11. A first SMA line 11 forming the first actuation unit 10 (e.g., the line on the left-hand side) is arranged to apply torque to the rotatable member 20 in a first direction (e.g., clockwise) during contraction. A second SMA line 11 forming the second actuation unit 10 (e.g., the line on the right-hand side) is arranged to rotate the rotatable member 20 in a second direction (e.g., counterclockwise) during contraction. The second direction is opposite to the first direction. In alternative embodiments, more or fewer SMA lines may be present, for example, a larger number of SMA lines 11 operating in groups operating in opposite rotational directions. In the case of only a single SMA line 11, a biasing element (not shown) may be present, which provides a return force acting in the opposite rotational direction. A group of SMA lines providing torque in a certain direction can be considered to consist of a single actuation unit 10, such that two or more actuation units 10 can be considered (…). Figure 4 Therefore, two actuation units 10 are shown, each actuation unit including a single SMA line 11. The SMA line 11 may be arranged in a loop around the main axis O or partially around the main axis O.

[0059] Zero holding power In traditional variable aperture assemblies, the actuation unit is constantly energized to maintain the blade position and keep the variable aperture at the desired size. Therefore, the power consumption of such traditional variable aperture assemblies is relatively high.

[0060] According to some embodiments (including) Figure 4 The variable aperture assembly 1 is configured such that one or more blades 40 maintain their positions when the actuation unit 10 is not actuated. Thus, the actuation unit 10 only needs to be energized when adjusting the size of the variable aperture. Therefore, the energy efficiency of the variable aperture assembly 1 according to an embodiment of the invention is improved.

[0061] The size of the variable aperture can be maintained when the actuation unit 10 is not actuated and when the acceleration of the variable aperture assembly 1 is less than or equal to a holding threshold. The holding threshold is the magnitude of the acceleration of the variable aperture assembly 1. When the acceleration is equal to or less than the holding threshold, the holding force (such as friction) is sufficient to maintain the size of the variable aperture. When the acceleration is greater than the holding threshold, the holding force (such as friction) may be insufficient to maintain the position of the blade 40. The holding threshold is set by the total force resisting the movement of the blade 40 when the actuation unit 10 is not actuated, and can therefore be determined by the coefficient of friction of the friction surfaces, the area of ​​the friction surfaces, and the normal force of the friction surfaces offset from each other. The holding threshold can be at least 1g (9.8 m / s²), or at least 2g (19.6 m / s²), optionally at least 5g (49.0 m / s²), optionally at least 10g (98.1 m / s²), optionally at least 20g (196 m / s²), and optionally at least 50g (490 m / s²). By increasing the retention threshold, the risk of unwanted movement of blade 40 is reduced.

[0062] Friction surfaces with zero holding power In some embodiments, the position of the blade 40 is maintained by the total frictional force between the components of the variable aperture assembly 1. This total frictional force can consist of frictional forces acting between any of the components of the variable aperture assembly 1. These frictional forces can vary in magnitude, direction, and whether they are affected by actuation of the actuation unit 10. For example, some of these frictional forces can remain constant when the actuation unit 10 is actuated, and some other frictional forces can be reduced or eliminated when the actuation unit 10 is actuated. When the actuation unit 10 is not actuated, all frictional forces contribute to the total frictional force resisting the movement of the blade 40.

[0063] Figure 4 An embodiment of the variable aperture assembly 1 is shown, wherein the actuation unit 10 is configured to reduce friction. The variable aperture assembly 1 includes a biasing device 35. The biasing device 35 may include a leaf spring as shown. Typically, the biasing device 35 may include any element or combination of elements capable of applying force between two or more components of the variable aperture assembly 1. The biasing device 35 may, for example, include elastic or resilient elements such as springs (e.g., coil springs, flexures, leaf springs), rubber bands, or other elastic or resilient elements. The biasing device 35 may be a magnetic device, comprising a magnet on one component and a magnet or ferromagnetic material on another component. The biasing device 35 may be arranged between two components or incorporated into one or more components of the variable aperture assembly 1.

[0064] Bias device 35 along the first direction ( Figure 4The rotatable component 20 is pushed downwards, thereby causing the friction surfaces 21 and 31 (which are respectively disposed on the rotatable component 20 and the base 30) to abut against each other. Two pairs of friction surfaces 21 and 31 are shown, each pair of friction surfaces including a first friction surface 31 and a second friction surface 21 that engage with each other.

[0065] exist Figure 4 In the illustrated embodiment, the actuation unit 10 formed by the SMA line 11 can be used to move the blade 40 to any position within its range of motion. When energized (i.e., when a drive signal is applied to the SMA line 11 via a control circuit), the SMA line 11 retracts and applies an actuating force to move the blade. The actuating force is sufficient to overcome the frictional forces at the friction surfaces 31, 32 (in some embodiments, after the frictional forces caused by the retraction of the SMA line have decreased or been eliminated) to drive the movement of the blade. When power to the SMA line 11 is stopped, and therefore when the SMA line 11 stops retracting, the zero-holding member (e.g., the blade) is held in position within its range of motion due to the frictional force between the first friction surface 31 and the second friction surface 21. In this state, the blade 40 is held in place with zero power consumption by the variable aperture assembly 1, which can therefore be referred to as the zero-holding power actuator assembly.

[0066] Figure 4 The biasing device 35 also includes a connecting element 35a disposed between the biasing element and the rotatable member 20. The connecting element 35a is a ball bearing. The connecting element 35a allows the rotatable member 20 to move relative to the biasing element. The biasing device 35 applies a biasing force over the entire range of motion of the rotatable member 20 relative to the base 30.

[0067] exist Figure 4 In the variable aperture assembly 1, the SMA lines 11 are at an angle α relative to each other and at an angle α / 2 relative to the biasing force applied by the biasing device 35. Therefore, a relatively small proportion of the stress in the SMA lines 11 is used to reduce the force applied by the biasing device 35 (and thus reduce the friction between the first friction surface 31 and the second friction surface 21), while a relatively large proportion of the stress in the SMA lines 11 enables rotation of the rotatable component 20. Equal actuation of the SMA lines 11 reduces friction without rotating the rotatable component 20. Unequal actuation of the SMA lines 11 causes the rotatable component 20 to rotate. The angle α (and therefore angle α / 2) can be selected based on the magnitude of the biasing force applied by the biasing device, the coefficient of friction and area of ​​the friction surfaces 21 and 31, and the actuating force applied when actuating the SMA lines 11.

[0068] exist Figure 4In the diagram, when viewed along the principal axis O, the SMA lines 11 intersect. Therefore, the SMA lines 11 are longer than if they were not allowed to intersect. Intersection of the SMA lines 11 is permitted because the angle α being depicted is relatively large. For smaller angles α, the SMA lines 11 may not need to intersect, while maintaining the same length.

[0069] The first friction surface 31 and the second friction surface 21 can engage with each other throughout the entire range of motion. Therefore, in normal use (i.e., under actuation of the actuation unit 10 for moving the rotatable component 20), at least some of the first friction surface 31 and the second friction surface 21 can remain engaged with each other (even if actuation of the SMA line 11 reduces friction). Alternatively, the first friction surface 31 and the second friction surface 21 can disengage when the actuation unit 10 is actuated (if the actuating force provided by the SMA line 11 exceeds the biasing force provided by the biasing device).

[0070] Actuation unit for stroke amplification Such as about Figure 1 and Figure 2 As explained, the relative movement of pins 23 and 33 enables the movement of blade 40 to adjust the size of the variable orifice. When actuation unit 10 is actuated, blade 40 ideally moves a relatively large distance to provide a relatively wide range of variable orifice sizes. However, due to limitations on the achievable stroke of the SMA line 11, actuation unit 10 consisting of a single SMA line 11 (such as...) is provided. Figure 4 The actuation unit (of the rotating component 20) may limit the achievable amount of rotation of the rotating component 20. This stroke limitation can be partially offset by arranging the pins 23 and 33 closer together, thereby amplifying a given amount of rotation of the rotating component 20 into a greater amount of movement of the blade 40. However, the proximity of the pins 23 and 33 may be limited by manufacturing considerations and tolerances, and the friction between the pins 23 and 33 and the blade 40 increases as the pins 23 and 33 are arranged closer together. More generally, regardless of the mechanism used to connect the blade 40 to the base 30 and the rotating component 20, the amount of achievable blade motion (e.g., blade rotation) may be limited for a given amount of relative motion between the base 30 and the rotating component 20. Furthermore, a high transmission ratio in the mechanism used to convert the relative motion between the base 30 and the rotating component 20 into blade motion can lead to undesirable backlash in the blade drive mechanism.

[0071] Therefore, it is desirable to increase the stroke of the SMA line 11 to a relatively larger amount of rotation of the rotatable component 20. Typically, this can be achieved by making the SMA line 11 at an angle relative to the tangent of the circle surrounding the main axis O (such as...). Figure 4(As shown in the diagram). For example, stroke amplification can be maximized by arranging the SMA line 11 at approximately 90 degrees relative to the tangent. However, this approach may carry the risk of the SMA line 11 overlapping with the variable aperture defined by the blade 40 (e.g., by the SMA line 11 extending toward the main axis), resulting in an increase in the coverage area of ​​the variable aperture assembly (e.g., by the SMA line 11 extending away from the main axis), and / or the need for large supports to resist the non-tangential forces of the SMA line 11.

[0072] The inventors have discovered that by providing an intermediate component 14 as part of the actuation unit 10 to amplify the stroke of the SMA line 11 to a relatively large amount of rotation of the rotatable component 20, a relatively wide range of variable aperture sizes can be achieved. This intermediate component 14 can be configured to be combined with the SMA line 11 to at least partially address the drawbacks of stroke amplification in the actuation unit 10 consisting of a single SMA line 11.

[0073] Figures 5A to 5C An embodiment of an actuator unit 10 is shown, including an intermediate component 14 and implementing stroke amplification of the SMA line 11. For example, Figures 5A to 5C The actuation unit 10 can be used in relation to Figures 1 to 4 The variable aperture component 1 described is implemented.

[0074] Figures 6 to 1 4 shows the variable aperture component 1 (e.g., regarding...) Figures 1 to 4 The described variable aperture assembly includes various types of actuation units 10, which have intermediate components 14 for stroke amplification.

[0075] Figure 5A A perspective view of an example of the actuation unit 10 is shown. Figure 5B A portion of the actuation unit 10 is shown in a plan view. Figure 5A and Figure 5B A single actuation unit 10 is shown, but it should be understood that the variable aperture assembly 1 typically has multiple actuation units 10 (typically a pair of opposing actuation units 10), each actuation unit may include a reference. Figure 5A and Figure 5B The same components are described.

[0076] The actuation unit 10 includes an intermediate component 14, also referred to herein as the main body portion 14, to which several other components of the actuation unit 10 are connected, as described below. Typically, the main body portion 14 is relatively rigid compared to the other components of the actuation unit and does not deform significantly when the actuation unit 10 is actuated. In some examples, the main body portion 14 is not a separate part of the actuation unit 10. For example, the main body portion 14 may be defined as part of one of the other components of the actuation unit 10, or simply as a connection point between the other components of the actuation unit 10.

[0077] The actuation unit 10 also includes a force adjustment element 12, depicted herein as a force adjustment flexure 12. The force adjustment flexure 12 is connected between the main body portion 14 and the support structure 30. One end of the force adjustment flexure 12 is connected to the main body portion 14. The other end of the force adjustment flexure 12 is connected to the base 30, for example, via a foot portion 16. The foot portion 16 is fixed relative to the base 30. The force adjustment flexure 12 allows the main body portion 14 to pivot relative to the base 30 about an effective pivot axis P. Although the effective pivot axis P is... Figure 5B The center is shown as being located in the middle of the force-adjusting flexure 12, but the effective pivot axis P can be in a different position and does not need to be located on the force-adjusting flexure 12. The pivoting movement of the main body 14 relative to the support structure 30 initially occurs in a direction substantially perpendicular to the force-adjusting flexure 12.

[0078] The actuation unit 10 also includes an SMA element 11 depicted as an SMA line 11. The SMA line 11 connects the main body portion 14 and the base 30. One end of the SMA line 11 is connected to the base 30, for example, via a connecting member 43 (such as a crimping member 43). The other end of the SMA line 11 is connected to the main body portion 14, for example, via a connecting member 42 (such as a crimping member 42).

[0079] The actuation unit 10 also includes a connecting element 15. In this example, the connecting element 15 is a connecting flexure 15. The connecting flexure 15 is connected between the main body portion 14 and the movable member 20. One end of the connecting flexure 15 is connected to the main body portion 14. The other end of the connecting flexure 15 is connected to the movable member 20. The connecting element 15 transmits or transfers the actuating force F from the main body portion 14 to the rotatable member 20. The connecting element 15 is flexible (i.e., deformable) in a direction perpendicular to the actuating force F (or multiple directions). This allows the movable member 20 to move in directions other than the direction of the connecting flexure 15 and the actuating force F. For example, this may be necessary in cases where different actuation units 10 cause the movable member 20 to move in different directions.

[0080] In this example, the main body 14, the force-adjusting flexure 12, the connecting flexure 15, and the support leg 16 are integrally formed, for example, from a single sheet of material (such as metal). In other examples, one or more of these features (if present) may be formed from different parts or materials.

[0081] SMA line 11 is arranged to apply an input force Fi to the main body portion 14 during contraction. The input force Fi acts parallel to the length of SMA line 11. Force adjusting flexure 12 and the main body portion 14 are arranged to adjust the input force Fi to generate an actuating force F, which is transmitted from the main body portion 14 to the movable member 20 via connecting flexure 15. Specifically, the input force Fi deforms the force adjusting flexure 12, thereby pivoting the main body portion 14 about an effective pivot axis P. Simply put, the force adjusting flexure 12 and the main body portion 14 act like levers. The force adjusting flexure 12 and the main body portion 14 can adjust the direction and / or magnitude of the input force Fi to generate the actuating force F.

[0082] exist Figure 5A and Figure 5B In the example shown, the connecting flexure 15 is at an angle of approximately 90° relative to the SMA line 11. Furthermore, in this example, the force-adjusting flexure 12 is arranged at an angle α of approximately 30° relative to the SMA line 11, and is under tension when the SMA line 11 contracts. Therefore, as the SMA line 11 contracts and the resulting force-adjusting flexure 12 deforms, the main body 14 initially moves at an angle of approximately 60° (90°-α) relative to the length of the SMA line 11. Thus, it should be understood that in this example, the force is reduced and the stroke is amplified, while the direction of force / movement is changed by approximately 90°.

[0083] More generally, the change in the direction of the force depends on the angle between the SMA line 11 and the connecting flexure 15. Also more generally, the change in the magnitude of the force depends on the ratio of i) the distance Ds from the effective pivot point P to the line containing the SMA line 11 and ii) the distance Dc from the effective pivot point P to the line containing the connecting flexure 15. Therefore, F / Fi is proportional to Ds / Dc. If the line containing the SMA line 11 is closer to the effective pivot point P than the line containing the connecting flexure 15, the input force Fi is reduced. Simultaneously, the motion of the end of the connecting flexure 15 connected to the main body 14 is amplified, i.e., increased relative to the length change of the SMA line 11. Alternatively, if the line containing the SMA line 11 is farther from the effective pivot point P than the line containing the connecting flexure 15, the input force Fi is amplified. Simultaneously, the motion of the end of the connecting flexure 15 connected to the main body 14 is de-amplified, i.e., decreased relative to the length change of the SMA line 11. Therefore, actuation unit 10 can be configured to amplify the movement caused by the contraction of SMA line 11 or the force caused by the contraction of SMA line 404. Actuation unit 10 can also be configured to change the direction of the input force Fi. In some examples, actuation unit 10 is configured to change the direction of the input force Fi without changing the magnitude of the force or movement.

[0084] The ratio Ds / Dc depends on the position of the SMA line 11 connected to the end of the main body 14 and the position of the connecting flexure 15 connected to the end of the main body 14. As an example, the connecting flexure 15 can be further connected to... Figure 5B The distance Dc is increased by moving the left side of the main body 14 shown, thereby decreasing Ds / Dc and thus increasing the stroke amplification. The ratio Ds / Dc also depends on the orientation of the SMA line 11 and the orientation of the connecting flexure 15. Such orientation can be defined with reference to the force-adjusting flexure 12 (as above) or any suitable reference line. As an example, this can be achieved by making... Figure 5B The SMA line 11 shown is angled so that it extends closer to the effective pivot axis P to reduce the distance Ds, thereby reducing Ds / Dc and thus increasing the stroke amplification. In summary, the amount by which the force-adjusting flexure 12 amplifies or reduces the force / stroke of the SMA line 11 can be customized in the following ways: - Adjust the orientation of SMA line 11 (and thus adjust the input force Fi); - Adjust the position of the connection point between the SMA line 11 and the main body 14 (and thus adjust the position of the input force Fi acting on the main body 14). - Adjust the orientation of the connecting flexure 15 (and thus adjust the actuation force F); and / or - Adjust the position of the connection point between the connecting flexure 15 and the main body 14 (and thus adjust the position where the actuating force F is applied to the main body 14).

[0085] In some examples, at least one actuation unit 10 (preferably each actuation unit 10) is configured such that the force-adjusting flexure 12 and the main body portion 14 amplify the amount of contraction of the SMA line 11 to a relatively large amount of rotation of the rotatable member 20 relative to the base 30. For example, such amplification factor may be greater than 1.5, preferably greater than 2, and more preferably greater than 3. It should be noted that the amplification factor may differ from the ratio Dc / Ds, considering that the amount of movement of the end of the connecting flexure 15 connected to the main body portion 14 relative to the base may differ from the amount of movement of the end of the connecting flexure 15 connected to the rotatable member 20 relative to the base.

[0086] As mentioned above, in Figure 5A and Figure 5B In the example shown, the connecting flexure 15 is at an angle of approximately 90 degrees relative to the SMA line 11. This allows the actuation unit 10 to fold the rotatable component 20 in a compact manner. The angle between the connecting flexure 15 and the SMA line 11 can be in the range of 70 to 110 degrees, preferably in the range of 80 to 100 degrees. However, typically, the angle between the connecting flexure 15 and the SMA line 11 can be outside these ranges.

[0087] For example, in Figure 5C In the actuation unit 10 shown, the force-adjusting flexure 12, the connecting flexure 15, and the SMA line 11 are substantially parallel to each other. The main body 14 acts as a first-class lever to adjust the input force Fi, thereby generating the actuating force F.

[0088] In the example above, the actuation unit 10 is arranged in a plane. Specifically, at least when the variable aperture assembly 1 is in its initial configuration, the SMA line 11, the connecting flexure 15, and the force-adjusting flexure 12 are arranged to extend substantially in a common plane. This allows for a compact configuration of the actuation unit 10. When implemented as a plate, the main body portion 14 can also be arranged to extend in this plane. However, typically, the components of the actuation unit 10 are not necessarily arranged in a common plane. For example, the SMA line 11 and / or the connecting flexure 15 may be angled relative to this plane.

[0089] In the example above, the force-adjusting deflector 12 is in a stretched state when the SMA line 11 contracts. This reduces the risk of buckling of the force-adjusting deflector 12, thereby reducing the risk of damage to the variable aperture assembly 1 and making the variable aperture assembly 1 more reliable. However, the force-adjusting deflector 12 can alternatively be arranged in a compressed state when the SMA line 11 contracts. (See reference...) Figure 5BFor example, the force-adjusting flexure 12 can extend downward and to the right from the connection point between the main body portion 14 and the force-adjusting flexure 12, and is therefore in a compressed state when the SMA line 11 contracts. An arrangement in which the force-adjusting flexure 12 is in a compressed state is disclosed in WO2022 / 084699A1, which is incorporated herein by reference.

[0090] In the above example, the actuation unit 10 includes a connecting element 15 in the form of a connecting flexure 15. Typically, the connecting element 15 can be implemented by a component other than the connecting flexure 15, such as a ball bearing or planar support configured to transmit the actuating force F to the rotatable member 20 while allowing the rotatable member 20 to move in a direction perpendicular to the actuating force F. Such an alternative example of the connecting element 15 is disclosed in the connecting link of WO2022 / 084699A1. The connecting element 15 may (or may not) be formed of an SMA line, which may (or may not) be integral with the SMA line 11 and may (or may not) be driven together with the SMA line 11. In a further alternative example, the connecting element 15 may correspond to a simple connection between the body portion 14 and the rotatable member 20, which does not allow the rotatable member 20 to move in a direction perpendicular to the actuating force F, for example, in an example where the rotatable member 20 does not move in a direction perpendicular to the actuating force F.

[0091] In the example described above, the actuation unit 10 includes a force adjustment element 12 in the form of a force-adjusting flexure 12. Typically, the actuation unit 10 may include different types of force adjustment elements 12 configured to enable the aforementioned movement (i.e., rotational movement) or other movements (e.g., translational movement) of the main body portion 14 relative to the base 30. Such a force adjustment element 12 may include, for example, a rigid member, one end of which is connected to the base 30 via a suitable rotary support or pivoting connection (e.g., pin engagement), and the other end connected to the main body portion 14 or a planar or rolling support device arranged to guide the translational movement of the main body portion 14 relative to the base 30.

[0092] In the example above, the force-adjustable deflector 12 and the SMA line 11 are connected to the base 30 at one end, and the connecting element 15 is connected to the rotatable component 20 at one end. Typically, this arrangement can also be reversed, in which the force-adjustable deflector 12 and the SMA line 11 are connected to the second component 20 at one end, and the connecting element 15 is connected to the base 30 at one end.

[0093] Variable aperture assembly with actuator unit for stroke amplification Figures 6 to 1 4. A plan view schematically depicting various embodiments of the variable aperture assembly 1 is shown. The variable aperture assembly 1 can be generally as described above. Figures 1 to 4The description, besides those related to... Figure 4 Aside from the differences described, the actuation unit 10 includes components for amplifying the travel of the SMA line 11, in addition to the SMA line 11. Figures 6 to 1 In embodiment 4, blade 40 and pins 23, 33 are not shown, but it will be apparent that blade 40 can be coupled with the above. Figure 1 and Figure 2 The base 30 and the rotatable component 20 are connected in the same manner as described (or in an alternative manner that may not be based on the use of pins).

[0094] Figures 6 to 1 The variable aperture assembly 1 of 4 includes two actuation units 10. Unless otherwise specified, the actuation units 10 can generally be configured as described above. Figures 5A to 5C As described. With Figures 5A to 5C In comparison, Figures 6 to 1 The actuation unit 10 is depicted more schematically in section 4.

[0095] Two actuation units 10 in Figures 6 to 1 Four relatively opposite arrangements. (Special reference) Figure 6 For example, the relative arrangement of actuation unit 10 means that the first actuation unit 10 ( Figure 6 The top actuation unit 10 is configured to cause the rotatable member 20 to rotate in a first direction (when actuated). Figure 6 Rotating clockwise in the middle, and the second actuation unit 10 ( Figure 6 The bottom actuation unit 10 is configured to, upon actuation, cause the rotatable member 20 to move in a second direction opposite to the first direction. Figure 6 The rotatable component 20 rotates in a counter-clockwise direction. Therefore, the two actuation units 10 can drive the rotation of the rotatable component 20 in opposite directions, thereby improving the response time of the rotation and the accuracy of its rotational position. Alternatively, although not shown, a single actuation unit 10 may be provided, which is opposite to an elastic element such as a spring.

[0096] Figure 6 A variable aperture assembly 1 is shown, which includes two actuation units 10, the two actuation units being about Figure 5C A general description of the type, including information about Figure 5A and Figure 5BThe description includes the main body 14, the force-adjusting flexure 12, and the connecting flexure 15. The main body 14 acts as a first-class lever to amplify the stroke of the SMA line 11. Each actuation unit 10 is configured to amplify the stroke of the SMA line 11 (typically the actuation amount of the SMA element 11, which can be a change in the length of the SMA line 11) to a relatively large amount of rotation of the rotatable member 20 (particularly the portion of the rotatable member 20 connected to the connecting element 15, corresponding to the position where the actuating force F acts on the rotatable member 20) relative to the base 30. Figure 6 In the position of the rotatable component 20 shown, the stroke amplification factor can be approximately equal to Dc / Ds, and... Figure 5C The actuation unit 10 is the same. This is because the connecting flexure 15 is tangent to the circle around the main axis O, so the end of the connecting flexure 15 connected to the main body 14 and the end of the connecting flexure 15 connected to the rotatable member 20 move in essentially series. However, in general, the stroke amplification factor may deviate from the ratio Dc / Ds, for example when the connecting flexure 15 (and the actuating force F) is at an angle to the tangent of the circle around the main axis O.

[0097] Two actuation units 10 are arranged on opposite sides of the main axis O. Figure 6 In the illustrated embodiment, the actuation units 10 are arranged mirror-symmetrically about an axis (horizontal axis) that intersects and is perpendicular to the main axis O. The actuation units 10 extend along opposite sides of the rotatable member 20 and / or the base 10 such that when viewed along the main axis O, the main axis O is located between the actuation units 10. Thus, the actuation units 10 can be arranged compactly around the rotatable member 20.

[0098] In the depicted embodiment, the two SMA lines 11 are parallel to each other and arranged on opposite sides of the main axis O, and are equidistant from the main axis O. Therefore, with... Figure 4 Compared to the arrangement of the SMA lines 11 shown, the heat generated at the center of the variable aperture due to the actuation of the SMA lines 11 (which are typically heated to be actuated) is more uniform. For example, when the variable aperture assembly 1 is adjacent to the lens element of the lens assembly 50, uneven heating may be undesirable because it risks asymmetrical effects on the optical properties of the lens. Generally, uniform heating can be achieved when the two SMA lines 11 are substantially parallel (e.g., at an angle of less than 10° or less than 5°). Figure 4 Compared to the arrangement of SMA lines 11 shown, the two SMA lines 11 can form an acute angle with each other, such as less than 45°, less than 30°, or less than 20°, to achieve more balanced heating. Generally, balanced heating can be achieved when the two SMA lines 11 are substantially equidistant from the main axis O, for example, when the difference in distance between each SMA line 11 and the main axis O is less than 10%, preferably less than 5%.

[0099] exist Figure 6 In, with Figure 1 and Figure 2 Unlike the previous configuration, the rotatable component 20 surrounds a portion of the base 30. Alternatively, as explained, the base 30 may surround the rotatable component 20.

[0100] Figure 7 Another embodiment of the variable aperture assembly 1 is depicted. (Compared to...) Figure 6 Compared to the actuator unit 10, Figure 7 The actuation unit 10 shown is arranged such that the connecting flexure 15 is approximately radially inward (i.e., closer to the main axis O) compared to the SMA line 11. The connection between the connecting flexure 15 and the main body portion 14 is positioned relative to the SMA line 11 in a direction toward the main axis O. Therefore, with Figure 6 Compared to the previous arrangement, the SMA line 11 can be positioned further away from the main axis O. Therefore, the heat generated at the center of the variable aperture due to the actuation of the SMA line 11 can be reduced, thereby lowering the risk of undesirably affecting any lens elements or other components adjacent to the variable aperture arrangement.

[0101] Figure 7 Another advantage of this arrangement (where the SMA line 11 is positioned further away from the main axis O compared to the connecting flexure 15) is that the risk of the SMA line 11 inadvertently passing through the optical path defined by the variable aperture when unenergized and relaxed is reduced. However, when the SMA line 11 is constrained to be fitted within the coverage area of ​​the variable aperture assembly 1, the maximum length of the SMA line 11, and therefore the maximum achievable travel of the SMA line 11 when positioned further away from the main axis O, can be reduced. The actuation unit 10 can compensate for this reduced maximum length by implementing a travel amplification.

[0102] Figure 7 The connecting flexures 15 of the actuation unit 10 shown are angled relative to each other and relative to the SMA line 11, such that the actuation force F is similar to that of the reference. Figure 4 The actuating force F applied by the SMA line 11 (which extends substantially along the length of the SMA line 11) is angled relative to each other. This arrangement of the actuating force F is particularly suitable for the effective modulation of the frictional force between the first and second friction surfaces in a zero-hold power actuator assembly. Although not specifically shown, Figure 7 The variable aperture assembly 1 can therefore include friction surfaces 21 and 31, which are biased against each other to achieve a zero holding power function, and the actuation unit 10 can be configured to reduce the frictional force during actuation. The friction surfaces 21 and 31 can, for example, be positioned on... Figure 7At the top interface between the rotatable component 20 and the base 30, a bias force pushes the rotatable component 20 upward, while the connecting flexure 15 applies an actuating force F in the downward direction.

[0103] For example Figure 7 As schematically shown, the actuating unit 10 can be configured such that the nominal lines of the forces acting on the body portion 14 are collinear. In other words, the forces acting on the body portion 10 can intersect, particularly at common points. (See also: Special Reference) Figure 7 i) the nominal line along the force applied to the main body 14 by the SMA line 11, ii) the nominal line along the force applied to the main body 14 by the connecting flexure 15, and iii) the nominal line along the force applied to the main body 14 by the force adjusting flexure 12 are concurrent lines. The forces applied by the connecting flexure 15 and the force adjusting flexure 12 can be in the direction along the length of the flexure. Although specifically for Figure 7 As shown, however, the actuation unit 10 in any other embodiment can be configured such that generally i) the nominal line of the force applied to the body portion 14 by the SMA element 11, ii) the nominal line of the force applied to the body portion 14 by the connecting element 15, and iii) the nominal line of the force applied to the body portion 14 by the force adjusting element 12 are concurrent lines. Such a configuration can reduce the risk of undesirable twisting of the flexural element, for example by allowing the body portion 14 to be nominally in equilibrium when equal tension is applied to the SMA line 11.

[0104] The three forces intersect when the main body 14 is in a specific position relative to the base 30 and / or relative to the rotatable member 20. This specific position can be the initial position of the main body 14, such as when the rotatable member 20 is at the center of its rotational position range relative to the base 30. The specific position can also be the position when the SMA lines 11 of the two actuating units 10 are actuated equally, such as... Figure 7 As shown in the diagram. A specific position can be the position when the connecting flexure 15 and / or the force-adjusting flexure 12 are straight, i.e., neither bent nor deformed, such as... Figure 7 As shown in the image.

[0105] like Figure 7 As shown, when viewed along the main axis O, the actuation unit 10 can be configured to be mounted within the coverage area of ​​the base 30 and the rotatable component 20, thereby achieving a particularly compact form factor for the variable aperture assembly 1. Figure 7The coverage area of ​​the base 30 and the rotatable component 20 can be considered as the smallest circle that fits around the base 30 and the rotatable component 20 when viewed along the main axis O. Therefore, the actuating unit 10 can completely overlap with this coverage area. The angle of the connecting flexure 15 relative to the SMA line 11 facilitates the overlap of the actuating unit 10 with the coverage area while avoiding overlap with the variable aperture defined by the blade 40 when the variable aperture is at its maximum size. The actuating unit 10 can be effectively bent around the main axis O to overlap with the annular base 30 and / or the annular rotatable component 20.

[0106] Although not shown, the actuation unit 10 can alternatively be configured to be mounted within a square coverage area. Such a square coverage area is typically obtained when the variable aperture assembly 1 is incorporated into a larger device (e.g., a smartphone camera that typically has a square coverage area). Therefore, the actuation unit 10 can be mounted within a minimum square (when viewed along the main axis O) surrounding the base 30 and the rotatable component 20. This arrangement of the actuation unit 10 allows for efficient use of space in the corners of the square, for example, using a similar arrangement as described above. Figure 6 The arrangement of the described actuation unit 10, Figure 6 Actuation units 10 are shown at adjacent corners of a square surrounding the variable aperture assembly 1.

[0107] Variable aperture assembly with long levers and / or alternately mounted actuators Figure 5 to Figure 7 The actuation unit 10 includes a relatively compact body portion 14, which is schematically depicted as being much shorter than the sides of the variable aperture assembly 1. The inventors have found that, in some cases, utilizing a longer body portion 14 and making greater use of the available space around the variable aperture is advantageous. This longer body portion 14 can act as a longer lever, thereby achieving a greater stroke magnification factor; for example, the stroke magnification factor of the different actuation units 10 can be more consistent, and / or the stroke magnification factor can be more consistent within the actuation range of the actuation unit 10, taking into account manufacturing tolerances.

[0108] Figures 8 and 9 illustrate this actuation unit 10 with a relatively large main body portion 14. The variable aperture assembly 1 is depicted more schematically in Figures 8 and 9 compared to the other figures, and is intended to illustrate the concept of a long lever. For illustrative purposes, some components (e.g., connecting parts 42, 43 or leg portions 16) other than the main body portion 14, SMA line 11, force adjustment element 12, and connecting element 15 are omitted in some figures of Figures 8 and 9, but these components may still be present. Figure 9B and Figure 9CThe base 30 and the rotatable component 20 are not shown; only the connection between the actuation unit 10 and the base 30 and the rotatable component 20 is shown, although the base 30 and the rotatable component 20 may still be present. It should be understood that the actuation unit 10 and its arrangement shown in Figures 8 and 9 can be used in the variable aperture assembly 1 described elsewhere in this application.

[0109] Figure 8A A variable aperture assembly 1, comprising opposing actuation units 10, is schematically shown. Each actuation unit 10 includes a relatively large body portion 14. Figure 8A In this configuration, the angular range β1 of the main body portion 14 is approximately 160°. The angular range β2 of the SMA line 11 is approximately 90°, and the angular range β3 of the connecting flexure 15 is approximately 90°. The range of each of the main body portion 14, the SMA line 11, and the connecting flexure 15 can be the distance between the ends of each of these features. When viewed along the main axis O, the angular ranges β1, β2, and β3 of each of the main body portion 14, the SMA line 11, and the connecting flexure 15 can be angular ranges with respect to the main axis O. In other words, each of the main body portion 14, the SMA line 11, and the connecting flexure 15 is a significant portion (typically greater than 50%) of the length of one of the four nominal equilateral sides extending around the main axis O (such as one of the four nominal equilateral sides of the smallest nominal square of the variable aperture assembly 1). Figure 8A The examples shown extend approximately 90%, 70%, and 65%, respectively.

[0110] Typically, the angle range β1 of the main body portion 14 can be at least 45°, preferably at least 60°, at least 80°, or at least 90°, thereby providing a relatively large main body portion 14. In some embodiments, for example Figure 8A In the embodiment shown, the angle range β1 of the main body 14 can be at least 135°. The angle range β2 of the SMA line 11 can be at least 45°, preferably at least 60°, at least 80°, or at least 90°. Providing a relatively long SMA line 11 allows for a relatively large stroke capacity. The angle range β3 of the connecting flexure 15 can be at least 45°, preferably at least 60°, at least 80°, or at least 90°. Providing a relatively long connecting flexure 15 allows for a relatively large angle range, reducing the stiffness of the connecting flexure 15 in the direction orthogonal to the actuation force F. In particular, the angle range of the connecting element 15 can be much smaller, especially in embodiments where connecting elements 15 other than the connecting flexure 15 (e.g., connecting supports) are provided.

[0111] like Figure 8AAs shown, the main body portion 14 can be bent between its ends, for example, between its connection point with the SMA line 11 and the connection point with the connecting flexure 15. The main body portion 14 can be bent in the same direction as the circle around the main axis O. Therefore, the main body portion 14 can be effectively bent around the main axis O to align with the annular shape of the rotatable component 20 and the base 30, thereby allowing the main body portion 14 to be longer without extending the coverage area of ​​the variable aperture assembly 1. The main body portion 14 can be bent such that the middle (e.g., the center) of the main body portion between its ends is closer to the main axis O than the ends of the main body portion 14.

[0112] exist Figure 8A In this embodiment, the SMA line 11, the main body portion 14, and the connecting flexure 15 are wound around the main axis O, or in other words, extend in a loop around the main axis O. Therefore, the SMA line 11, the main body portion 14, and the connecting flexure 15 may overlap only minimally at their ends, but when viewed radially outward from the main axis O, a large portion (i.e., at least 50%, optionally at least 75% or at least 90%) of the SMA line 11, the main body portion 14, and the connecting flexure 15 may not overlap. Therefore, the extension range of the actuating unit 10 in the radially outward direction from the main axis O can be reduced. The combined angular range β1+β2+β3 of the combination of the SMA line 11, the main body portion 14, and the connecting flexure 15 is approximately equal to the sum of the angular ranges of each of the SMA line 11, the main body portion 14, and the connecting flexure 15, thus in Figure 8A The angle is approximately 340°. Typically, the combined angle range β1+β2+β3 can be at least 90°, preferably at least 150° or at least 180°. In some embodiments (not shown), the combined angle range β1+β2+β3 can be greater than 360°, such that when viewed along the main axis O, the SMA line 11 of the same moving unit 10 and the connecting flexure 14 intersect or overlap in the angle range.

[0113] Figure 8A The actuation unit includes a force adjustment element 12, schematically depicted as a rotary support 12, which can be achieved by pin engagement, for example, a pin protruding from the base 30 through a corresponding hole in the body portion 14, to allow the body portion 14 to rotate about a pivot axis P defined by the pin. Such pin engagement can also typically be provided by a pin protruding from the body portion 14 that engages a corresponding hole in the base 30.

[0114] Figure 8B Another variable aperture assembly 1 is schematically shown, which includes an actuation unit 10 with a relatively large body portion 14. (Compared to...) Figure 8A Compared to the actuator unit 10, Figure 8BThe actuation unit 10 includes a force adjustment element 12 in the form of a force adjustment flexure 12. In addition to the curvature of the main body 14 varying along its extension, the main body 14 is in relation to... Figure 8A The same bending manner is described. Therefore, the main body 14 can be designed, for example, to avoid collisions with other components of the variable aperture assembly 1, such as avoiding overlap between the main body 12 of one actuation unit 10 and the force-adjusting flexure 12 of another actuation unit 10 (when viewed along the main axis).

[0115] When viewed along the principal axis O Figure 8A and Figure 8B The actuation units 10 overlap each other. For example, two connecting flexures 15 overlap, two main body portions 14 overlap, and the SMA line 11 of each actuation unit 10 overlaps with the main body portion 14 and connecting flexure 15 of the other actuation unit 10. This overlap achieves a compact arrangement of the actuation units 10 within the coverage area of ​​the variable aperture assembly 1, but may increase the height of the variable aperture assembly 1 along the main axis O and / or make the assembly of the actuation units 10 in the variable aperture assembly 1 more complex.

[0116] Figure 9A Another variable aperture assembly 1 is schematically shown, which includes an actuation unit 10 with a relatively large body portion 14, wherein the actuation units 10 are arranged not to overlap when viewed along the main axis O. When viewed perpendicular to the main axis O, the two actuation units 10 can overlap. Overlap of the actuation units 10 when viewed along the main axis O is avoided by alternately mounting the actuation units 10 to the base 30 and the rotatable component 20. In particular, the first actuation unit 10 ( Figure 9A The SMA cable 11 and force-adjusting flexure 12 of the bottom actuation unit 10 are connected to the base 30, and the connecting flexure 15 of the first actuation unit 10 is connected to the rotatable component 20. The second actuation unit 10 ( Figure 9A The SMA line 11 and force-adjusting flexure 12 of the top actuation unit 10 are connected to the rotatable component 20, and the connecting flexure 15 of the second actuation unit 10 is connected to the base 30. The two actuation units 10 can be configured equivalently in other ways, i.e., having the same arrangement of the main body 14, SMA line 11, force-adjusting flexure 12, and connecting flexure 15. Therefore, overlap of the two actuation units 10 is avoided without changing the design of one of them. The SMA lines 11 of the two actuation units 10 are also arranged on opposite sides of the main axis O, thereby enabling relatively even heating of the center of the variable aperture when the SMA lines 11 are actuated.

[0117] Figure 9AEach actuating unit 10 is wound around a main axis O such that the SMA line 11, the body portion 14, and the connecting flexure 15 are arranged on three adjacent sides of a nominal square surrounding the variable aperture assembly 1. The body portions 14 of opposite actuating units 10 are arranged on opposite sides of the main axis O. The SMA line 11 of the first actuating unit 10 and the connecting flexure 15 of the second actuating unit 10 are arranged on the same side, and the connecting flexure 15 of the first actuating unit 10 and the SMA line 11 of the second actuating unit 10 are arranged on the same side. In the depicted embodiment, the SMA line 11 of one actuating unit 10 is parallel to the connecting flexure 15 of another actuating unit 10, but typically the SMA lines 11 and connecting flexures 15 of different actuating units 10 can be arranged at a small angle to each other while avoiding overlap.

[0118] Figure 9B and Figure 9C An alternative arrangement of the actuation unit 10 is shown, which is alternately mounted to the base 30 and the rotatable component 20. The base 30 and the rotatable component 20 are not shown, but the connection between the actuation unit 10 and the base 30 and the rotatable component 20 is indicated by the relevant reference numerals. Figure 9C The arrangement of the actuation unit 10 is basically as described above. Figure 9A As described, although the force adjusting element 12 is schematically shown as a rotary support 12 rather than a force adjusting deflector 12. (The image shows...) Figure 9B The arrangement of the actuation units 10 is shown to illustrate that in an arrangement with alternating installations of the actuation units 10, it is not necessary to avoid overlap, for example, depending on the desired coverage area of ​​the variable aperture assembly 1.

[0119] Despite Figures 9A to 9C The concept of an alternative installation of the actuation unit 10 is specifically illustrated in conjunction with the relatively large main body portion, but it is obvious that such an alternative installation can be used in combination with any other actuation unit 10 described herein.

[0120] An actuation unit having a translational main body and / or a connecting main body. The actuation unit 10, schematically shown in Figures 5 through 9, achieves stroke amplification by allowing the main body portion 14 to rotate about the real or effective pivot axis P, thereby allowing the main body portion 14 to be used as a lever. Figures 10 and 11 schematically show variable aperture assemblies 1 of different types of actuation units 10, wherein the main body portion 14 is translated at an angle with the input force Fi applied by the SMA line 11.

[0121] Special Reference Figure 10AEach actuation unit 10 includes a force adjustment element 12 in the form of a translational support 12. In the depicted embodiment, the translational support 12 connects the main body portion 14 and the base 30, and is therefore arranged between the main body portion 14 and the base 30. The translational support 12 is shown as a rolling support, including a rolling support element (e.g., a ball bearing or roller) between a support surface on the main body portion 14 and a support surface on the base 30. Typically, other types of translational supports 12 may be used, such as planar or sliding supports that guide translational movement, or flexural supports that include a set of two or more flexures that guide translational movement.

[0122] The translational support 12 guides the movement of the main body 14 along the moving axis M, which is angled relative to the input force Fi applied by the SMA line 11. Figure 10A In the middle, the moving axis M defined by the left translation support 12 is in the upper left direction, and the input force Fi acts in the vertical direction along the SMA line 11. Figure 10A In this configuration, the angle γ between the moving axis M and the input force Fi is approximately 70°. Typically, the angle γ can be in the range of 45° to 90°, for example, between 60° and 85°. The stroke amplification increases as the angle γ approaches 90°.

[0123] When the SMA line 11 is actuated, the translational support 12 is loaded by pushing the support surfaces against each other, and the translational movement of the main body 14 along the movement axis M is guided by the translational support 12. During the translational movement of the main body 14, the actuating force F is applied to the rotatable member 20 through the connecting flexure 15, thereby causing the rotatable member 20 to rotate relative to the base 30. The length variation of the SMA line 11 is amplified to a relatively large rotation of the end of the connecting flexure 15 connected to the rotatable member 20. The amplification factor typically depends on the angle γ and the position of the end of the connecting flexure 15 connected to the rotatable member 20 relative to the main axis O.

[0124] For example Figure 10A As shown, the actuating unit 10 can be configured such that the nominal lines of the forces acting on the body portion 14 are concurrent lines. In other words, the forces acting on the body portion 10 can intersect, particularly at common points. (See also: Special Reference) Figure 10AThe nominal lines along (i) the force applied to the main body 14 by the SMA line 11, (ii) the force applied to the main body 14 by the connecting flexure 15, and (iii) the force applied to the main body 14 by the translational support are concurrent lines. The force applied to the main body 14 by the translational support 12 is perpendicular to the axis of motion M. This configuration can reduce the risk of undesirable torsion of the flexure element and undesirable rotation about the translational support 12, for example, by allowing the main body 14 to be nominally in equilibrium when equal tension is applied to the SMA line 11.

[0125] The three forces intersect when the main body 14 is in a specific position relative to the base 30 and / or relative to the rotatable member 20. This specific position can be the initial position of the main body 14, such as when the rotatable member 20 is at the center of its rotational position range relative to the base 30. The specific position can also be the position when the SMA lines 11 of the two actuating units 10 are actuated equally, such as... Figure 10A As shown in the diagram. A specific location can be the location where the connecting flexure 15 is straight (i.e., not bent), such as... Figure 10A As shown.

[0126] Figure 10A The actuation unit 10 is configured such that the connecting flexure 15 and a portion of the main body 14 (particularly the portion between the connecting portion 42 and the translation support 12) are in a compressed state when the SMA line 11 is actuated.

[0127] Figure 10B Another actuation unit 10 is shown, in which the main body 14 is translated at an angle to the input force Fi applied by the SMA line 11. The angle γ is not in... Figure 10B Or the markings in the subsequent diagrams, but may be as per the description. Figure 10A As stated above. (and) Figure 10A Compared to the actuator unit 10, Figure 10B The actuation unit 10 is configured such that its components are in a tensioned state when the SMA line 11 is actuated. Therefore, the risk of buckling of the components of the actuation unit 10 (especially the connecting flexure 15) can be reduced.

[0128] A translational support 12 is arranged on the main body 14, located between the connection point of the SMA line 11 and the main body 14, and the connection point of the connecting flexure 15 and the main body 14. Therefore, the entire main body 14 can be in a tensioned state when the SMA line 11 is actuated. The connecting flexure 15 is configured to extend away from the main body 14 in a direction opposite to the movement of the main body 14 when the SMA line 11 is actuated. In contrast, in Figure 10AIn the middle, the connecting flexure 15 folds back onto the main body 14 in the direction of movement of the main body 14, and thus overlaps with the main body 14 when viewed perpendicular to the axis of movement M.

[0129] Figure 10A and Figure 10B The connecting flexure 15 can be configured to be relatively rigid in order to effectively convert the translation of the main body 14 into the rotation of the rotatable member 20. The connecting flexure 15 can allow some compliance to allow the main body 14 to rotate relative to the rotatable member 20.

[0130] Figures 6 to 1 The two opposing actuation units 10 of the variable aperture assembly 1 are shown as being completely separate. For example, actuation of the SMA line 11 of one actuation unit 10 can indirectly affect the movement of the body portion 14 of the other actuation unit 10 only via the connecting element 15.

[0131] Figure 11A and Figure 11B The opposing actuation units 10 with connected body parts 14 are schematically shown. The movement of one body part 14 due to the actuation of the corresponding SMA line 11 directly affects the movement of the other body part 14, due to the connecting element 14a between the body parts 14.

[0132] Special Reference Figure 11A Connecting elements 14a are disposed between the main body portions 14. As shown, the connecting elements 14a can be integrally formed with the main body portions 14 or can be fixedly connected to the main body portions 14. Therefore, the two main body portions 14 are connected such that when one of the SMA elements 11 is actuated, the two main body portions 14 move back and forth.

[0133] Figure 11A The connecting element 14a is a flexible member extending between the main body portions 14. The flexible member allows force to be transmitted along its length from one main body portion 14 to another, while allowing relative movement of the main body portions 14 in a direction orthogonal to the length of the flexible member. For example, when... Figure 11A When the left-side SMA element 11 is actuated, the left-side main body portion 14 is pushed to the left to apply tension in the left connecting flexure 15, thereby applying an actuating force to the rotatable member 20. Due to the connecting member 14a, the right-side main body portion 14 is also pushed to the left to apply compression to the right-side connecting flexure 15, thereby applying an actuating force to the rotatable member 20. Thus, even when only one SMA line 11 of one of the actuating units 10 is actuated, the connecting flexure 15 of both actuating units 10 acts on the rotatable member 20.

[0134] Figure 11B The connecting element 14a is a relatively rigid component that is fixedly connected to the main body portion 14, preventing relative movement of the main body portions 14. The two main body portions 14 and the connecting element 14a form a single larger body, and can therefore be collectively referred to as the common body portion. Thus, the two actuation units 10 can be considered to share the common body portion. The common body portion is connected to two connecting flexures 15, which can be referenced when actuated by only one SMA line 11. Figure 11A The described method applies to the rotatable component 20.

[0135] Using connecting element 14a to join the main body parts 14 together (or providing a single common main body part) can reduce the risk of undesirable deformation of the connecting flexure 15, which is not translated into rotation of the rotatable part 20.

[0136] An actuation unit having a connecting element formed as a support device The actuation unit 10 shown in Figures 5 to 11 includes a connecting element 15 in the form of a connecting flexure 15. Other types of connecting elements 15 may be provided instead of the connecting flexure 15 in any of Figures 5 to 11. Figure 12 An embodiment of the actuation unit 10 is shown, which includes a connecting element 15 in the form of a connecting support 15.

[0137] In the illustrated embodiment, a coupling support 15 connects the main body portion 14 and the rotatable component 20, and is therefore arranged between the main body portion 14 and the rotatable component 20. The coupling support 15 is shown as a support element (e.g., a ball bearing or roller) included between a support surface on the main body portion 14 and a support surface on the rotatable component 20. Typically, other types of coupling supports 15 may be used, such as pivot supports or any other mechanism that allows the main body portion 14 to rotate relative to the rotatable component 20.

[0138] The connecting support 15 transmits the actuating force F to the rotatable component 20 while being flexible in a direction orthogonal to the actuating force F, for example by allowing relative movement of the support surfaces in a direction orthogonal to the actuating force F. In the depicted embodiment, the main body 14 can rotate about an effective pivot axis P provided by the force-adjusting flexure 12, thereby causing rotation of the rotatable component 20 via the connecting support 15. (See also: [details omitted]) Figure 12 The main body 14 on the left can rotate clockwise to allow the rotatable component 20 to rotate counterclockwise. The connecting support 15 allows relative rotation between the main body 14 and the rotatable component 20.

[0139] Replacement Actuation Unit Figure 13A variable aperture assembly including another type of actuation unit 10 is schematically depicted.

[0140] The actuation unit 10 includes a relatively large body portion 14. For example, the angular range of the body portion 14 can be as described with respect to Figures 8 and 9. In the depicted embodiment, the angular range of the body portion 14 about the main axis O is greater than 180°. The force adjustment element 12 is implemented by a rotary support (e.g., pin engagement) that allows the body portion 14 to rotate about the pivot axis P. The body portion 14 serves as a first-class lever for amplifying the stroke of the SMA line 11.

[0141] The main body 14 is effectively shared by the two actuation units 10 because the two SMA lines 11 are aligned with the reference. Figure 11B The described actuation unit 10 acts on the main body 14 in the opposite manner. The first SMA line 11 is configured to drive the main body 14 to rotate about the pivot axis P relative to the base 30 in a first direction, while the second SMA line 11 is configured to drive the main body 14 to rotate about the pivot axis P relative to the base 30 in a second direction opposite to the first direction.

[0142] The main body 14 is connected to the rotatable component 20 via a connecting element 15. The connecting element 15 is only located on the rotatable component 20. Figure 13 The diagram is schematically shown and can be configured to transmit actuation force to the rotatable member 20 while allowing the main body portion 14 to rotate relative to the rotatable member 20. The connecting element 15 can be, for example, as shown in Figures 10 to 1990. Figure 12 Implemented as shown in any of the connecting elements 15.

[0143] Figure 14A A schematic depiction of... Figure 10A The variable aperture assembly 1 is similar to the variable aperture assembly 1 of the same type, except that it provides different types of connecting elements 15 for each actuation unit 10.

[0144] Figure 14B Detailed illustration Figure 14A The variable aperture assembly 1 includes a connecting element 15. The connecting element 15 is a rotary support 15, which includes a pivot arm on the main body portion 14 that engages a support surface of a groove in the rotatable member 20. The pivot arm can slide relative to the support surface to allow the main body portion 14 to rotate relative to the rotatable member 20. For example, in… Figure 14A When the left SMA line 11 shown is actuated, Figure 14B The left main body shown rotates counterclockwise, thereby pushing the pivot arm to the left against the support surface of the rotatable component 20, so as to drive the rotatable component 20 to rotate clockwise.

[0145] Figure 14BThe connecting element 15 can typically be used in any variable aperture assembly 1 described herein, for example, instead of Figures 6 to 13 Connecting element 15.

[0146] Other variations It will be understood that many other variations of the above example may exist.

[0147] Many of the actuation units 10 described herein have been described as including force-adjusting elements 12 in the form of force-adjusting deflectors 12. Typically, the force-adjusting deflector 12 can be replaced by any element or mechanism capable of guiding the body portion 14 to rotate about a real or effective pivot axis. It is apparent that stroke amplification can be achieved in a manner equivalent to that described by replacing the force-adjusting deflector 12 with a rotary support (e.g., a rotary engagement (e.g., a pin engagement) and / or including a contact support capable of rolling and / or sliding relative to the support surface of the rotary support).

[0148] from Figure 7 , Figure 8A / Figure 8B , Figure 10A / Figure 10B as well as Figure 11A and Figure 12 It is evident from this that the connecting element 15 is configured to be similar to that regarding Figure 4 The described manner applies an actuating force F at an angle relative to each other. The variable aperture component 1 in any of these figures may include a friction surface (although not specifically shown in some figures) to achieve, as referenced... Figure 4 The zero-holding power function mentioned above. Figure 10A / Figure 10B and Figure 11A In this case, the friction surfaces can be biased together by opposite upward biasing forces (not shown), which can be reduced by an actuating force having a downward component.

[0149] Similarly, alternately mounted to the rotatable component 20 and the base 30 Figures 9A to 9C The actuation unit 10 can be similar to that about Figure 4 The described method applies a force (actuating force F or input force Fi) that is typically at an angle to each other to the rotatable components, and thus enables zero holding power functionality.

[0150] Figures 6 to 1 Embodiment 4 includes an actuator 10 configured to provide stroke amplification for the SMA element 11. (See also: Regarding...) Figure 5BAs described, the actuation unit 10 can alternatively be configured to amplify the input force Fi to a relatively large actuating force F, for example, by repositioning the pivot axis P (e.g., by adjusting the flexure 12 or the rotation support 12 by repositioning the force), such that the lever arm provided by the body portion 14 for the input force Fi is greater than the lever arm provided by the body portion 14 for the actuating force. For example, such force amplification might be desirable for moving a particularly heavy rotatable component 20. By providing this force amplification (and thus effectively reducing the stroke), the rotational position of the rotatable component 20 can be set more precisely.

[0151] Although the variable aperture assembly 1 has been described in the context of optical systems for adjusting the amount of light entering the lens assembly 50, it should be understood that the variable aperture assembly 1 can be used in other applications. The variable aperture assembly 1 can be used to adjust the passage of any material through the aperture. For example, the variable aperture assembly 1 can be used as a variable valve to adjust the flow rate of fluids (e.g., liquids or gases, such as air) passing through a conduit. The variable aperture assembly 1 can also be used to control the passage of particles other than photons, for example, to adjust beams of charged particles, such as in electron microscopes.

[0152] The rotatable component 20, which is rotatable relative to the base 30, and the arrangement of the actuation unit 10 for driving such rotation have already been described in the context of the variable aperture assembly 1. It will be apparent that the actuation unit 10 described herein can be used to drive the rotation of the rotatable component 20 relative to the base 30 for any other purpose. Therefore, the variable aperture assembly 1 described herein may be more generally referred to as actuator assembly 1. The base 30 may also be referred to as support structure 10.

[0153] Another type of actuator assembly 1, including a rotatable component 20 and an actuation unit 10, is an actuator assembly 1 including a third component, wherein a helical support device guides the helical movement of the third component relative to the rotatable component, and a translational support device guides the translational movement of the third component relative to the base 30. The actuation unit 10 can be used to drive the rotation of the rotatable component 20 relative to the base 30, which is converted into translational movement of the third component along the main axis O by the helical support device and the translational support device. The third component may, for example, include one or more lenses, and can therefore be used to implement autofocus or zoom functions in a camera device.

[0154] SMA The aforementioned SMA actuator assembly includes at least one SMA element. Each SMA element may be divided into one or more SMA element segments. The term "shape memory alloy (SMA) element" may refer to any element that includes an SMA. An SMA element may be described as an SMA line. 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 shape. The cross-section may vary along the length of the SMA element. An SMA element may have a relatively complex shape, such as a helical spring shape. It is also possible that the length of the SMA element (however defined) may be similar to one or more of the other dimensions of the SMA element. An SMA element may be sheet-like, and such sheet may be planar or non-planar. An SMA element may be flexible, or in other words, a flexible SMA element. In some examples, when connected in a straight line between two members, the SMA element can only apply tension that forces the two members together. In other examples, the SMA element may bend around a member, and the SMA element may apply a force to the member when the SMA element tends to straighten under tension. SMA elements can be beam-shaped or rigid and may be capable of applying different forces (e.g., non-tensional) 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 materials. Unless the context requires otherwise, the term "SMA element" may refer to any configuration of SMA material that acts as a single actuating element, for example, which can be individually controlled to generate forces acting on the element. For example, an SMA element may include two or more portions of SMA material arranged mechanically 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 components that can be individually controlled, thereby forming two or more SMA elements. SMA elements may include SMA wires, SMA foils, SMA films, or any other configuration of SMA material. SMA elements can be manufactured using any suitable method, such as by methods involving drawing, rolling, deposition, sintering, or powder melting. SMA elements can exhibit any shape memory effect, such as thermal shape memory or magnetic shape memory, and can be controlled in any suitable way, such as by Joule heating, another heating technique, or by applying a magnetic field.

[0155] SMA components can typically include nitinol (nickel-titanium), although other types of SMA materials can often be used.

[0156] Alternative methods for heating SMA Heating of thermally activated actuators (such as SMA materials) to move moving parts can be achieved in a variety of ways.

[0157] In one arrangement, the material can be heated by passing an electric current through it. This current may come from a local or external power source. Alternatively, a current can be induced in a line through an inductive connection to an external alternating field. In the case of two actuators, the two actuators can be designed such that they are connected to two different frequencies of the induced power source, thereby allowing the two actuators to be heated differently.

[0158] In another arrangement, the material can be heated by external radiation such as visible light or infrared laser. The external radiation can be focused such that one actuator is heated before another, thus allowing differential actuation. Alternatively or additionally, different actuators or portions of actuators can be treated (e.g., with surface coatings) such that the different actuators heat at different rates depending on the nature of the incident radiation (e.g., frequency).

Claims

1. An actuator assembly, comprising: Base; A rotatable component, the rotatable component being able to rotate about a main axis relative to the base; and One or more actuation units, each configured to apply an actuating force capable of rotating the rotatable component relative to the base about the main axis, each actuation unit comprising: - Main body; - A shape memory alloy SMA element, the shape memory alloy SMA element being connected between the main body portion and one of the base and the rotatable component, and configured to apply an input force to the main body portion when the actuation unit is actuated; - A force adjustment element, which connects the main body portion to one of the base and the rotatable component, and is configured such that the input force is adjusted to generate the actuating force; and - A connecting element that connects the main body portion to the base and the other of the rotatable components, and is capable of transmitting the actuating force to the other of the base and the rotatable component.

2. The actuator assembly according to claim 1, wherein, The actuation unit is configured to amplify the change in actuation amount of the SMA element to a relatively large amount of movement of the portion of the coupling element that is connected to the base and the other of the rotatable components.

3. The actuator assembly according to claim 1 or 2, wherein, When viewed along the main axis, the angle range of the main body portion around the main axis is at least 60° or at least 90°.

4. The actuator assembly according to any one of the preceding claims, wherein, When viewed along the main axis, the SMA element, the main body portion, and the connecting element extend in a circle around the main axis.

5. The actuator assembly according to any one of the preceding claims, comprising two actuation units configured to, upon actuation, cause the rotatable member to rotate relative to the base about the main axis in opposite directions.

6. The actuator assembly of claim 5, wherein, The SMA elements of the two actuation units are substantially parallel to each other and arranged on opposite sides of the main axis.

7. The actuator assembly according to claim 5 or 6, wherein, The SMA elements of the two actuation units are substantially equidistant from the main axis.

8. The actuator assembly according to any one of claims 5 to 7, wherein, The first actuation unit of the two actuation units is configured such that a corresponding SMA element is connected between the main body and the base, a corresponding force adjustment element is connected between the main body and the base, and a corresponding connecting element is connected between the main body and the rotatable component. and The second actuation unit of the two actuation units is configured such that a corresponding SMA element is connected between the main body and the rotatable component, a corresponding force adjustment element is connected between the main body and the rotatable component, and a corresponding connecting element is connected between the main body and the base.

9. The actuator assembly according to any one of claims 5 to 8, wherein, The two actuation units are configured not to overlap when viewed along the main axis.

10. The actuator assembly according to any one of claims 5 to 9, wherein, The main body portions of the two actuation units are directly connected to each other or are formed integrally.

11. The actuator assembly according to any one of the preceding claims, wherein, The one or more actuation units are configured to completely overlap with the smallest square and / or smallest circle surrounding the base and the rotatable component when viewed along the main axis.

12. The actuator assembly according to any one of the preceding claims, wherein, i) The nominal line along the force applied to the main body by the SMA element, ii) the nominal line along the force applied to the main body by the connecting element, and iii) the nominal line along the force applied to the main body by the force adjusting element are concurrent lines.

13. The actuator assembly according to any one of the preceding claims, wherein, The force adjustment element is configured to guide the rotation of the main body relative to one of the base and the rotatable component when the SMA element is actuated.

14. The actuator assembly of claim 13, wherein, The force adjustment element includes a force adjustment flexure configured to bend when the SMA element is actuated in order to guide rotation about the body portion relative to one of the base and the rotatable component.

15. The actuator assembly of claim 13, wherein, The force adjustment element includes a swivel support configured to guide rotation of the main body portion relative to one of the base and the rotatable component about a pivot axis.

16. The actuator assembly according to any one of claims 1 to 12, wherein, The force adjustment element includes a support device configured to guide the main body portion to translate relative to one of the base and the rotatable component along a moving axis, wherein the moving axis is at an angle to the direction of the input force.

17. The actuator assembly according to any one of the preceding claims, wherein, The connecting element allows relative movement between the main body portion and the other of the base and the rotatable component in a direction orthogonal to the actuation force.

18. The actuator assembly of claim 17, wherein, The connecting element includes a connecting flexure that connects the main body portion to the other of the base and the rotatable component.

19. The actuator assembly of claim 17, wherein, The connecting element includes a connecting support member, which includes a first supporting surface on the main body portion, a second supporting surface on the other of the main body and the rotatable component, and a supporting element between the first supporting surface and the second supporting surface.

20. The actuator assembly according to any one of the preceding claims, wherein, Each actuation unit is configured such that the corresponding connecting element is arranged closer to the main axis than the corresponding SMA element.

21. The actuator assembly according to any one of the preceding claims, wherein, The actuator assembly also includes a pair of friction surfaces that abut against each other by a biasing force, thereby generating static friction between the pair of friction surfaces to maintain the position of the rotatable component relative to the base when the at least one actuation unit is not actuated.

22. The actuator assembly of claim 21, wherein, The at least one actuating unit is arranged such that the bias force between the pair of friction surfaces decreases when the actuating unit is actuated, thereby reducing the static friction force between the pair of friction surfaces.

23. A variable aperture assembly, comprising: The actuator assembly according to any one of the preceding claims; and Multiple blades are configured such that rotation of the rotatable component relative to the base causes movement of the blades, thereby changing the size of the variable aperture.

24. A camera, comprising: The variable aperture assembly according to claim 23; Lens assembly; and Image capture device; The optical axis of the lens assembly coincides with the main axis, such that light passing through the variable aperture assembly is focused by the lens and received by the image capture device.

25. An electronic device comprising the camera according to claim 24.

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