Actuator assembly

Abstract

The actuator assembly (102) comprises: a movable portion (3); a support structure (4); a main axis defined relative to the support structure; actuator means (41, 42) configured to move the movable portion in at least one predetermined direction relative to the support structure; and biasing means (30) configured to assist the actuator means in moving the movable part in at least one predetermined direction when the movable part is moved away from the intermediate position.

Description

[0001] field

[0002] The present application relates to an actuator assembly comprising an actuator device configured to move a movable part relative to a support structure, and comprising a biasing device configured to assist the actuator device in moving the movable part.

[0003] background

[0004] It is known to use an actuator assembly to drive the movement of a movable part relative to a support structure. Such actuator assemblies are used in various devices, including handheld devices, such as cameras and mobile phones.

[0005] For example, such actuator assemblies are used in optical devices such as cameras for driving translational movement of a camera lens element along its optical axis, for example to achieve focusing (autofocus, AF) or zooming. An example of such an actuator assembly is disclosed in WO 2008 / 099155 A1, which discloses a miniature camera lens actuation device providing an automatic macro function, wherein the camera lens element has two focus positions.

[0006] Such actuator assemblies are also used, for example, in cameras for driving relative movement between a lens assembly and an image sensor, for example to achieve optical image stabilization (OIS). An example of such an actuator assembly is disclosed in WO 2013 / 175197 A1, which discloses an SMA (shape memory alloy) actuation device that moves a movable element relative to a support structure in two orthogonal directions using a total of four SMA actuator wires, each SMA actuator wire being connected at its end between the movable element and the support structure and extending perpendicularly to the main axis.

[0007] Such an actuator assembly is also used, for example, in a pop-up camera (also known as a retractable lens camera or a telescopic camera) to drive translational movement of a camera lens assembly along its optical axis so as to move the lens assembly between a retracted / folded state (e.g., where the lens assembly is unable to focus an image on an image sensor and / or where the pop-up camera is in a non-operating state) and an extended / pop-up state (e.g., where the lens assembly is able to focus an image on the image sensor and where the pop-up camera is in an operational state).

[0008] Such actuator assemblies are also used in cameras including variable apertures, for example to change the aperture size defined by the variable aperture. An example of such an actuator assembly is disclosed in WO 2018 / 206768 A1, which broadly discloses an actuator including a shape memory alloy (SMA) actuator wire that can be used to deliver a relatively large output stroke.

[0009] It is desirable for such an actuator assembly to have a biasing device configured to assist the actuator device in moving the movable part relative to the support structure so as to, for example, increase the stroke of the actuator device, i.e. increase the amount by which the movable part can be moved by the actuator device, and / or improve the efficiency of the actuator device.

[0010] Overview

[0011] According to one aspect of the present invention, an actuator assembly is provided, comprising: a movable part, a support structure, a main axis defined relative to the support structure, an actuator device and a biasing device. The actuator device is configured to (directly or indirectly) move the movable part relative to the support structure in at least one predetermined direction. The biasing device is configured to (directly or indirectly) assist the actuator device in moving the movable part along at least one predetermined direction when moving the movable part away from the intermediate position. The main axis can correspond to or be parallel to the longitudinal axis of the actuator assembly. At least one predetermined direction can be along, around and / or perpendicular to the main axis.

[0012] By providing a biasing device, the stroke of the actuator device may be increased. When the movable part is moved away from the neutral position, the movable part may move a greater distance in at least one predetermined direction for a given level of actuation of the actuator device than when the biasing device is not present. The stroke and / or gain of the actuator assembly may be increased without unduly reducing the accuracy of the movement.

[0013] By providing a biasing device, the efficiency of the actuator device may be improved. When moving the movable part away from an intermediate position, the actuator device may require less energy to move the movable part a certain distance in at least one predetermined direction than when the biasing device is not present. Additionally or alternatively, less or no energy may be required to keep the movable part at certain positions within its range of movement, for example at the ends of the possible range of movement of the movable part.

[0014] Optionally, the intermediate position is a position between the ends of the possible range of movement of the movable part relative to the support structure (ie not at any end) and a position in which the movable part can be in equilibrium. This position may be referred to as an intermediate equilibrium position.

[0015] Optionally, the biasing means is configured to enable the moveable part to be moved to a position outside the range of positions to which the moveable part can be moved by the actuator means without the assistance of the biasing means.

[0016] In other words, the range of positions to which the moveable part may be moved by the actuator means with support from the biasing means may be greater than the range of positions to which the moveable part may be moved by the actuator means without said support from the biasing means.

[0017] Optionally, the biasing device is configured to provide said assistance to the actuator device by applying a force on the movable part (i.e., assisting the actuator device to move the movable part in at least one predetermined direction). The force may be at least partially perpendicular to at least one predetermined direction, and / or at least partially in the same direction as the predetermined direction. The force may be applied directly to the movable part. The force may be applied indirectly to the movable part via the intermediate part or another intermediate part, which will be discussed in more detail below. In other words, the biasing device can be configured to apply a force to the movable part, wherein at least one component is in a predetermined direction.

[0018] Optionally, the actuator means comprises at least one SMA element, eg configured to drive said movement of the movable part upon contraction.

[0019] Optionally, the actuator assembly comprises a bistable device comprising a biasing device. The bistable device may be configured (directly or indirectly) to cause the movable part to have a first stable equilibrium position, a second stable equilibrium position and an unstable equilibrium position between the first stable equilibrium position and the second stable equilibrium position; wherein the unstable equilibrium position corresponds to the intermediate position. The first stable equilibrium position may be a first position along or around the main axis. The second stable equilibrium position may be a second position along or around the main axis, and the unstable equilibrium position may be a third position along or around the main axis between the first stable equilibrium position and the second stable equilibrium position.

[0020] Optionally, the first stable equilibrium position and the second stable equilibrium position correspond to ends of a possible range of movement of the movable part relative to the support structure.

[0021] Optionally, the at least one predetermined direction comprises a direction at least partially along the main axis.

[0022] Optionally, the main axis corresponds to or is parallel to a longitudinal axis of the actuator assembly.

[0023] Optionally, the movable part comprises a lens assembly configured to focus an image on the image sensor; and the principal axis corresponds to an optical axis of the lens assembly. The lens assembly may comprise one or more lenses.

[0024] Optionally, the actuator assembly is configured so that in the first stable equilibrium position the distance between the lens assembly and the image sensor along the principal axis is smaller than the distance between the lens assembly and the image sensor along the principal axis in the second stable equilibrium position. In other words, in the first stable equilibrium position the lens assembly is in a retracted / folded position, and in the second stable equilibrium position the lens assembly is in a popped-out / extended position.

[0025] Optionally, the lens assembly includes one or more lenses, and the actuator assembly includes a focus (e.g., AF) actuator configured to drive relative movement between the one or more lenses and the image sensor along a primary axis.

[0026] Optionally, the lens assembly is arranged so that the lens assembly cannot focus the image onto the image sensor when the movable part is in a first equilibrium position, and is configured so that the lens assembly can focus the image onto the image sensor when the movable part is in a second equilibrium position.

[0027] Optionally, the actuator means is configured to rotate the movable part relative to the support structure about the main axis.The rotation of the movable part may be driven directly by the actuator means, or indirectly by the actuator means via an intermediate part.

[0028] Optionally, the actuator assembly comprises a helical bearing device, which supports the movable part on the support structure and is arranged to guide the helical movement of the movable part relative to the support structure about the main axis; wherein the helical bearing device converts the rotation of the movable part about the main axis into the helical movement of the movable part. Alternatively, the actuator assembly comprises a helical bearing device, which supports the movable part on the intermediate part and is arranged to guide the helical movement of the movable part relative to the intermediate part; wherein the helical bearing device converts the rotation of the intermediate part about the main axis into the helical movement of the movable part.

[0029] Optionally, the movable portion forms part of a variable aperture (e.g., an iris diaphragm) assembly, the variable aperture assembly being configured such that rotation of the movable portion relative to the support structure about a principal axis changes an aperture (size) of the variable aperture assembly; and wherein the principal axis corresponds to an optical axis of the variable aperture assembly. The aperture of the variable aperture assembly is the opening through which light travels to reach the image sensor.

[0030] Optionally, the bistable device (e.g., a biasing element of the bistable device) is configured to bias the movable part toward the first stable equilibrium position (directly or indirectly) when the movable part is between the first stable equilibrium position and the unstable equilibrium position, and is configured to bias the movable part toward the second stable equilibrium position when the movable part is between the second stable equilibrium position and the unstable equilibrium position.

[0031] Optionally, the actuator arrangement (e.g. with the aid of the biasing arrangement) is configured to (directly or indirectly) drive movement of the movable part from the first stable equilibrium position to the second stable equilibrium position, and optionally (directly or indirectly) drive movement of the movable part from the second stable equilibrium position to the first stable equilibrium position. The first SMA element of the actuator arrangement may be configured to drive movement of the movable part from the first stable equilibrium position to the second stable equilibrium position. The second SMA element of the actuator arrangement may be configured to drive movement of the movable part from the second stable equilibrium position to the first stable equilibrium position.

[0032] Optionally, the actuator device (e.g., the first SMA element) is configured to (directly or indirectly) drive the movement of the movable part from a first stable equilibrium position to a first tilting position, wherein the first tilting position is a position between the unstable equilibrium position and the second stable equilibrium position; and wherein the bistable device (e.g., the biasing element) is capable of driving (and is configured to drive) the movement of the movable part from the first tilting position to the second stable equilibrium position without (drive / force) assistance from the actuator device. The actuator device (e.g., the first SMA element) can be configured to (directly or indirectly) drive the movement of the movable part from the first stable equilibrium position to the first tilting position until the unstable equilibrium position against the biasing force of the bistable device / biasing element.

[0033] Optionally, the actuator device (e.g., the second SMA element) is configured to (directly or indirectly) drive the movement of the movable part from the second stable equilibrium position to the second tilting position, wherein the second tilting position is a position between the unstable equilibrium position and the first stable equilibrium position; and wherein the bistable device (e.g., the biasing element) is capable of driving (and is configured to drive) the movement of the movable part from the second tilting position to the first stable equilibrium position without (drive / force) assistance from the actuator device. The actuator device (e.g., the second SMA element) can be configured to (directly or indirectly) drive the movement of the movable part from the second stable equilibrium position to the second tilting position until the unstable equilibrium position against the biasing force of the bistable device / biasing element.

[0034] Optionally, the actuator device includes one or more shape memory alloy (SMA) elements (e.g., two or four SMA elements) that are configured to (directly or indirectly) move the movable part relative to the support structure in at least one predetermined direction (e.g., along, around and / or perpendicular to the main axis).

[0035] Optionally, (each of) the one or more SMA elements are (directly or indirectly) coupled to the movable part and the support structure. Some or all of the one or more SMA elements may be directly coupled to the movable part and the support structure via a coupling component such as a crimp. Some or all of the one or more SMA elements may be indirectly coupled to the movable part and the support structure via, for example, a bistable device.

[0036] Optionally, the one or more SMA elements include: a first SMA element, which is configured to drive relative movement of the movable part in a first direction (at least partially along, around and / or perpendicular to the main axis) when contracted; and a second SMA element, which is configured to drive relative movement of the movable part in a second opposite direction (at least partially along, around and / or perpendicular to the main axis) when contracted, wherein the first direction and the second direction are opposite directions.

[0037] Optionally, the actuator assembly includes an intermediate portion movable relative to the support structure and the movable portion; and wherein the actuator device (e.g., the one or more SMA elements) is configured to move the movable portion relative to the support structure (indirectly via the intermediate portion) by moving the intermediate portion relative to the support structure and the movable portion.

[0038] Optionally, (each of) the one or more SMA elements are coupled (directly or indirectly) to the intermediate portion and the support structure. Some or all of the one or more SMA elements may be coupled directly to the intermediate portion and the support structure via a coupling component such as a crimp. Some or all of the one or more SMA elements may be coupled indirectly to the intermediate portion and the support structure via, for example, a bistable device.

[0039] Optionally, the one or more SMA elements include: a first SMA element, which is configured to (indirectly) drive the movable part to move relative to each other in a first direction (at least partially along, around and / or perpendicular to the main axis) when contracted; and a second SMA element, which is configured to (indirectly via the intermediate part) drive the movable part to move relative to each other in a second opposite direction (at least partially along, around and / or perpendicular to the main axis) when contracted.

[0040] Optionally, the intermediate portion is configured to move at least partially in a direction perpendicular to the main axis.

[0041] Optionally, the intermediate portion is configured to rotate about a primary axis.

[0042] Optionally, the one or more SMA elements are not configured to move the intermediate portion along the primary axis.

[0043] Optionally, the bistable mechanism is configured such that the intermediate portion has a first stable equilibrium position, a second stable equilibrium position, and an unstable equilibrium position between the first stable equilibrium position and the second stable equilibrium position.

[0044] When the middle part moves to its first stable equilibrium position, the movable part can also move to its first stable equilibrium position. When the middle part moves to its second stable equilibrium position, the movable part can also move to its second stable equilibrium position. When the middle part moves to its unstable equilibrium position, the movable part can also move to its unstable equilibrium position.

[0045] The bistable mechanism may also be configured such that only the movable part is bistable.

[0046] Optionally, the intermediate part and the movable part are connected to each other via intermediate support means, wherein the intermediate support means are configured such that when the intermediate part is moved by the actuator means, the movable part also moves (relative to the support structure).

[0047] Optionally, the actuator assembly comprises a further intermediate part between the intermediate part and the movable part, wherein the actuator device (e.g. one or more SMA elements) is configured to move the movable part relative to the support structure (indirectly) via the intermediate part and the further intermediate part.

[0048] Optionally, the intermediate part and the further intermediate part are connected to each other via intermediate support means, wherein the intermediate support means are configured such that when the intermediate part is moved by the actuator means the further intermediate part also moves (eg relative to the support structure and eg relative to the intermediate part).

[0049] Optionally, the intermediate bearing means comprises a bearing surface (which for example forms part of the intermediate part and the movable part, or forms part of the intermediate part and a further intermediate part) which is angled relative to a plane perpendicular to the main axis.

[0050] Optionally, there is a certain amount of clearance (ie, play) between the moveable portion and the component of the actuator assembly that is configured to directly move the moveable portion (ie, the intermediate portion or another intermediate portion).

[0051] Optionally, the amount of the gap is at least equal to an amount of displacement (eg, linear or rotational displacement) that the movable portion is configured to undergo when moving from the unstable equilibrium position to the first stable equilibrium position or the second stable equilibrium position.

[0052] Optionally, the support structure includes a first endstop and a second endstop, the first endstop being configured to engage the movable part when the movable part is in a first stable equilibrium position, and the second endstop being configured to engage the movable part when the movable part is in a second stable equilibrium position.

[0053] Optionally, the bistable arrangement is configured to maintain the moveable part in the first stable equilibrium position, the second stable equilibrium position or the unstable equilibrium position when the actuator arrangement does not move the moveable part relative to the support structure.

[0054] Optionally, the actuator assembly comprises at least one guide bearing configured to guide movement of the movable part relative to the support structure.

[0055] Optionally, the actuator assembly comprises at least one guide support configured to guide movement of the intermediate portion relative to the support structure.

[0056] Optionally, the actuator assembly comprises at least one guide support configured to guide movement of the intermediate portion relative to the support structure.

[0057] Optionally, the actuator assembly comprises at least one pivot rod (eg an articulated rod) configured to guide movement of the movable portion (and / or the intermediate portion and / or the further intermediate portion) relative to the support structure.

[0058] Optionally, (each of) the one or more SMA elements are parallel, perpendicular, or at an acute angle (eg, tilted) relative to the primary axis.

[0059] Optionally, the biasing means comprises a resilient member (eg a spring or flexure) and / or one or more magnets, the biasing means being configured to provide said assistance to the actuator means.

[0060] Optionally, the bistable device comprises a bistable flexible body.

[0061] Optionally, the actuator device includes: a first SMA element, which is connected to a first side of the bistable flexible body at its end, and a second SMA element, which is connected to a second side of the bistable flexible body at its end; wherein the first side and the second side of the bistable flexible body are opposite sides of the bistable flexible body.

[0062] Optionally, the actuator device includes: a first SMA element and a second SMA element, each of which is connected to a support structure at one end and to a first side of a bistable flexible body at the other end, and a third SMA element and a fourth SMA element, each of which is connected to a support structure at one end and to a second side of the bistable flexible body at the other end; wherein the first side and the second side of the bistable flexible body are opposite sides of the bistable flexible body.

[0063] Optionally, the intermediate position is a stable equilibrium position.

[0064] Optionally, the actuator assembly comprises a centering device configured to bias the moveable part towards the intermediate position.

[0065] Optionally, the biasing means comprises one or more magnets arranged to provide said assistance to the actuator means.

[0066] Optionally, the movable part is movable relative to the support structure in two orthogonal directions perpendicular to the main axis; and wherein at least one predetermined direction comprises one (or more) directions in the plane of the two orthogonal directions.

[0067] Optionally, the actuator device comprises (a total of) four SMA elements (e.g., SMA wires), which are connected between the movable part and the support structure in the device, wherein the SMA elements can be selectively driven to move the movable part to any position within the range of movement relative to the support structure without applying any net torque to the movable part in planes in two orthogonal directions around the main axis.

[0068] Optionally, the movable portion includes an image sensor and / or a lens assembly.

[0069] Optionally, the moveable part comprises a display, an emitter or a part thereof.The principal axis may be parallel to the general direction in which light is emitted by the display or emitter. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0072] Figure 1 is a schematic diagram of an actuator assembly having two opposing SMA elements arranged to move a movable portion;

[0073] Figure 2 is a schematic diagram of an actuator assembly having two opposing SMA elements arranged to move a movable portion via an intermediate portion;

[0074] Figure 3 is a schematic diagram of an actuator assembly having two opposing SMA elements arranged to move a movable portion via an intermediate portion in a first position;

[0075] Figure 4 It is in the second position Figure 3 A schematic diagram of an actuator assembly;

[0076] Figure 5 It is in the third position Figure 3 A schematic diagram of an actuator assembly;

[0077] Figure 6 It is in the fourth position Figure 3 A schematic diagram of an actuator assembly;

[0078] Figure 7 It is in the fifth position Figure 3 A schematic diagram of an actuator assembly;

[0079] Figure 8 It is in the sixth position Figure 3 A schematic diagram of an actuator assembly;

[0080] Fig. 9 is a schematic diagram of an actuator assembly having two opposing SMA elements arranged to move a movable portion via an intermediate portion;

[0081] Fig.10 is a schematic diagram of an actuator assembly having two opposing SMA elements arranged to move a movable portion via an intermediate portion and another intermediate portion;

[0082] Fig.11 is a schematic diagram of an actuator assembly having two angled opposing SMA elements arranged to move a movable portion;

[0083] Fig.12 is a schematic diagram of the support device;

[0084] Fig.13 is a schematic diagram of a pivoting lever;

[0085] Fig.14 is a schematic diagram of an actuator assembly having a bistable device;

[0086] Fig.15 is a schematic diagram of an actuator assembly having a bistable device;

[0087] Fig.16is a schematic diagram of an actuator assembly having a bistable device;

[0088] Fig.17 is a schematic diagram of an actuator assembly having a bistable flexible body;

[0089] Fig.18 is a schematic diagram of an actuator assembly having a bistable compliant body in a first position;

[0090] Fig.19 yes Fig.18 A schematic diagram of an actuator assembly of , wherein the bistable compliant body is in a second position;

[0091] Fig. 20 is a schematic diagram of an actuator assembly having two opposing SMA elements arranged to rotate a movable portion in a first position;

[0092] Fig.21 It is in the second position Fig. 20 A schematic diagram of an actuator assembly;

[0093] Fig. 22 is a schematic diagram of an actuator assembly having a movable portion in a first position;

[0094] Fig.23 yes Fig. 22 A schematic diagram of an actuator assembly of , wherein the movable portion is in a second position;

[0095] Fig.24 is a schematic diagram of an actuator assembly having four SMA elements.

[0096] Detailed Description

[0097] A. Bistable Actuator Assembly

[0098] Figure 1 is a schematic diagram of an actuator assembly 100 having two opposing SMA elements 31 , 32 arranged to move a movable part 3 relative to a support structure 4 upon selective contraction.

[0099] exist Figure 1 In the embodiment, the SMA elements 31, 32 (i.e., Figure 1 The actuator arrangement ) is arranged to move the movable part 3 translationally along a main axis (not shown) in a direction M. However, the SMA elements 31, 32 may alternatively be arranged to move the movable part 3 around the main axis (ie to rotate the movable part 3 around the main axis).

[0100] The first SMA element 31 is disposed on a first side of the movable part 3, and the second SMA element 32 is disposed on a second, opposite side of the movable part 3. The two SMA elements 31, 32 are coupled to the movable part 3 at a first end and to the support structure 4 at a second end. However, one or both of the SMA elements 31, 32 may alternatively be coupled to the support structure 4 or the movable part 3 at both ends and have a central portion coupled (e.g., hooked) to the other of the support structure 4 and the movable part 3. The first SMA element 31 is configured to drive the movable part 3 to move in a first direction relative to the support structure 4 when contracted. The second SMA element 32 is configured to drive the movable part 3 to move in a second, opposite direction relative to the support structure 4 when contracted.

[0101] At least one guide bearing may be provided, which is configured to guide the movement of the movable part 3 relative to the support structure 4 .

[0102] In case the SMA elements 31, 32 are arranged to rotate the intermediate part 40 around the main axis, a spiral support device may be provided between the support structure 4 and the movable part 3. The spiral support device may support the movable part 3 on the support structure 4 and may be arranged to guide the spiral movement of the movable part 3 around the main axis relative to the support structure 4, i.e., the spiral support device may be arranged to convert the rotation of the movable part 3 around the main axis into the spiral movement of the movable part 3 relative to the support structure 4.

[0103] The bistable device (not shown) is configured to make the movable part 3 behave in a bistable manner, ie to make the movable part 3 have a first stable equilibrium position, a second stable equilibrium position and an unstable equilibrium position therebetween.

[0104] When the movable part 3 is moved to the first stable equilibrium position, for example, by the actuator device, the bistable device provides a biasing force that keeps the movable part 3 in the first stable equilibrium position. Similarly, when the movable part 3 is moved to the unstable equilibrium position, for example, by the actuator device, the biasing force of the bistable device keeps the movable part 3 in the unstable equilibrium position. Similarly, when the movable part 3 is moved to the second equilibrium position, for example, by the actuator device, the biasing force of the bistable device keeps the movable part 3 in the second equilibrium position. The biasing force is weak enough to allow the actuator device to move the movable part 3 between the three equilibrium positions. Of course, considering that the movable part 3 is unstable in the unstable equilibrium position, in practice, it may be difficult for the actuator assembly to move and keep the movable part 3 in this position.

[0105] The first and second stable equilibrium positions may correspond to ends of a range of movement in which the movable part 3 is arranged to be moved by the actuator arrangement relative to the support structure 4. The unstable equilibrium position may correspond to the centre of said range of movement.

[0106] The support structure 4 may include a first end stop configured to engage the movable part 3 when the movable part 3 is in the first stable equilibrium position. The support structure 4 may also include a second end stop configured to engage the movable part 3 when the movable part 3 is in the second stable equilibrium position.

[0107] The bistable device (which can be considered as part of the biasing device, as it exerts a biasing force on the movable part 3) assists the actuator device in moving the movable part 3 relative to the support structure 4 when the movable part 3 is moved away from the unstable equilibrium position (which can also be referred to as an intermediate position) and, for example, towards the first equilibrium position or the second equilibrium position. In other words, the bistable device is configured to bias the movable part 3 towards the first stable equilibrium position when the movable part 3 is moved, for example, by the actuator device, to a position between the first stable equilibrium position and the unstable equilibrium position. And the bistable device is configured to bias the movable part 3 towards the second stable equilibrium position when the movable part 3 is moved, for example, by the actuator device, to a position between the second stable equilibrium position and the unstable equilibrium position. This helps, for example, to increase the stroke of the actuator device, i.e. to increase the amount by which the movable part 3 can be moved by the actuator device, and / or to improve the efficiency of the actuator device.

[0108] The actuator device (e.g., the first SMA element 31) may be configured (e.g., only) to drive the movement of the movable part 3 from the first stable equilibrium position to the first tilting position, wherein the first tilting position is a position between the unstable equilibrium position and the second stable equilibrium position, and the bistable device may be configured to drive the movable part 3 from the first tilting position to the second stable equilibrium position by itself, i.e., without the driving force / force assistance from the actuator device. Similarly, the actuator device (e.g., the second SMA element 32) may be configured (e.g., only) to drive the movement of the movable part 3 from the second stable equilibrium position to the second tilting position, wherein the second tilting position is a position between the unstable equilibrium position and the first stable equilibrium position, and the bistable device may be configured to drive the movable part 3 from the first tilting position to the second stable equilibrium position by itself, i.e., without the driving force / force assistance from the actuator device. In other words, the bistable device may be configured to enable the movable part 3 to move to a position beyond the range of positions to which the movable part 3 can be moved by the actuator device without the assistance from the bistable device. In other words, the range of positions to which the movable part 3 can be moved by the actuator device with support from the bistable device can be greater than the range of positions to which the movable part 3 can be moved by the actuator device without said support from the bistable device.

[0109] Figure 2 is a schematic diagram of an actuator assembly 101 having two opposing SMA elements 41 , 42 arranged to move the movable part 3 relative to the support structure 4 via the intermediate part 40 upon selective contraction, ie to move the movable part 3 indirectly via the intermediate part 40 .

[0110] exist Figure 2 In the embodiment, the SMA elements 41, 42 (i.e., Figure 2 The SMA elements 41, 42 are arranged to move the intermediate part 40 in translation in a direction S perpendicular to the main axis (i.e. the axis along / around which the movable part 3 is arranged to move). However, the SMA elements 41, 42 may alternatively be arranged to move the intermediate part 40 around the main axis (i.e. rotate the intermediate part 40 around the main axis).

[0111] The intermediate part 40 and the movable part 3 are connected to each other via an intermediate support device 43. The intermediate support device 43 is configured so that when the intermediate part 40 moves relative to the support structure 4 (e.g., in this example in a direction S perpendicular to the main axis) via the SMA elements 41, 42, the movable part 3 also moves relative to the support structure 4 (e.g., in this example in a direction M along the main axis).

[0112] The first SMA element 41 is disposed on a first side of the middle portion 40, and the second SMA element 42 is disposed on a second, opposite side of the middle portion 40. The two SMA elements 41, 42 are coupled to the middle portion 40 at a first end and to the support structure 4 at a second end. However, one or both of the SMA elements 41, 42 may alternatively be coupled to the support structure 4 or the middle portion 40 at both ends and have a central portion coupled (e.g., hooked) to the other of the support structure 4 and the middle portion 40. The first SMA element 41 is configured to drive the middle portion 40 to move in a first direction relative to the support structure 4 when contracted. The second SMA element 32 is configured to drive the movable portion 3 to move in a second, opposite direction relative to the support structure 4 when contracted.

[0113] The intermediate bearing device 43 comprises bearing surfaces of the intermediate part 40 and the movable part 3, which bearing surfaces are angled relative to a plane perpendicular to the main axis. The interaction between the intermediate part 40 and the movable part 3 via the slopes of the angled bearing surfaces provides an amplification of the stroke. The intermediate bearing device 43 may comprise a ball bearing between the bearing surfaces, such as Figure 2 In case the SMA elements 41 , 42 are arranged to rotate the intermediate portion 40 about the main axis, the bearing surface may be a helical bearing surface.

[0114] At least one guide support is provided, which is configured to guide the movement of the movable part 3 relative to the support structure 4. At least one guide support 33 is provided, which is configured to guide the movement of the intermediate part 40 relative to the support structure 4.

[0115] To ensure that the intermediate part 40 and the movable part 3 are directly mechanically coupled to each other (with no play / clearance between them), the intermediate part 40 and the movable part 3 are biased relative to each other by one or more biasing members (not shown) (such as springs and / or magnets).

[0116] The bistable device (not shown) is configured to make the intermediate part 40 behave in a bistable manner, that is, to make the intermediate part 40 have a first stable equilibrium position, a second stable equilibrium position, and an unstable equilibrium position between the first stable equilibrium position and the second stable equilibrium position. Because the intermediate part 40 and the movable part 3 are directly mechanically coupled to each other (without play / clearance between them), the bistable device also indirectly makes the movable part 3 behave in a bistable manner via the intermediate part 40, that is, to make the movable part 3 have a first stable equilibrium position (when the intermediate part 40 is in its first stable equilibrium position), a second stable equilibrium position (when the intermediate part 40 is in its second stable equilibrium position), and an unstable equilibrium position between the first stable equilibrium position and the second stable equilibrium position (when the intermediate part 40 is in its unstable equilibrium position).

[0117] When the intermediate part 40 and the movable part 3 are moved to their first stable equilibrium position, for example by the actuator device, the bistable device provides a biasing force that keeps the intermediate part 40 and the (indirectly) movable part 3 in their first stable equilibrium position. Similarly, when the intermediate part 40 and the movable part 3 are moved to their unstable equilibrium position, for example by the actuator device, the biasing force of the bistable device keeps the intermediate part 40 and the (indirectly) movable part 3 in their unstable equilibrium position. Similarly, when the intermediate part 40 and the movable part 3 are moved to their second equilibrium position, for example by the actuator device, the biasing force of the bistable device keeps the intermediate part 40 and the (indirectly) movable part 3 in their second equilibrium position. The biasing force is weak enough to allow the actuator device to move the intermediate part 40 and the (indirectly) movable part 3 between their three equilibrium positions. The bistable device may include one or more elastic or resilient members (e.g., one or more springs) and / or one or more magnets, the one or more elastic or resilient members and / or the one or more magnets being arranged along a direction defined by the Figure 2 The middle portion 40 is biased in the direction indicated by the arrow S in FIG.

[0118] The first and second stable equilibrium positions may correspond to ends of a range of positions to which the intermediate part 40 and the movable part 3 can be moved by the actuator means relative to the support structure 4. The unstable equilibrium position may correspond to the centre of said range of positions.

[0119] The support structure 4 may include an end stop configured to engage the middle part 40 when the middle part 40 is in its first stable equilibrium position. The support structure 4 may also include an end stop configured to engage the middle part 40 when the middle part 40 is in its second stable equilibrium position. Additionally or alternatively, the support structure 4 may include an end stop configured to engage the movable part 3 when the movable part 3 is in its first stable equilibrium position, and optionally, the end stop is configured to engage the movable part 3 when the movable part 3 is in its second stable equilibrium position.

[0120] The bistable device (which can be considered as part of the biasing device, as it applies a biasing force) assists the actuator device in moving the movable part 3 (indirectly via the intermediate part 40) relative to the support structure 4 when (indirectly) the movable part 3 is moved away from its unstable equilibrium position (which can also be called an intermediate position) and, for example, towards its first equilibrium position or second equilibrium position. In other words, the bistable device is configured to bias the movable part 3 (indirectly via the intermediate part 40) towards its first stable equilibrium position when the movable part 3 is, for example, moved (indirectly) by the actuator device to a position between its first stable equilibrium position and its unstable equilibrium position. It is also configured to bias the movable part 3 (indirectly) towards its second stable equilibrium position when the movable part 3 is, for example, moved (indirectly) by the actuator device to a position between its second stable equilibrium position and its unstable equilibrium position. This helps, for example, to increase the stroke of the actuator device, i.e. to increase the amount by which the movable part 3 can be moved by the actuator device, and / or to improve the efficiency of the actuator device.

[0121] The actuator device (e.g., the first SMA element 41) may be configured (e.g., only) to (indirectly) drive the movement of the movable part 3 from the first stable equilibrium position to the first tilting position, wherein the first tilting position is a position between the unstable equilibrium position and the second stable equilibrium position, and the bistable device may be configured to (indirectly) drive the movable part 3 from the first tilting position to the second stable equilibrium position by itself, i.e., without the driving force / force assistance from the actuator device. Similarly, the actuator device (e.g., the second SMA element 42) may be configured (e.g., only) to (indirectly) drive the movement of the movable part 3 from the second stable equilibrium position to the second tilting position, wherein the second tilting position is a position between the unstable equilibrium position and the first stable equilibrium position, and the bistable device may be configured to (indirectly) drive the movable part 3 from the first tilting position to the second stable equilibrium position by itself, i.e., without the driving force / force assistance from the actuator device. In other words, the bistable device may be configured to (indirectly) enable the movable part 3 to be moved to a position that exceeds the range of positions to which the movable part 3 can be moved (indirectly) by the actuator device without assistance from the bistable device. In other words, the range of positions to which the movable part 3 can be moved (indirectly) by the actuator device with support from the bistable device may be greater than the range of positions to which the movable part 3 can be moved (indirectly) by the actuator device without said support from the bistable device.

[0122] Bistable actuator assembly with gap

[0123] Figures 3 to 8 is a schematic diagram of an actuator assembly 102 having two opposing SMA elements 41 , 42 arranged to move the movable part 3 relative to the support structure 4 via the intermediate part 40 upon selective contraction, ie arranged to move the movable part 3 indirectly via the intermediate part 40 .

[0124] Figures 3 to 8 The actuator assembly 102 and Figure 2 The actuator assembly 101 is similar. The main difference is Figures 3 to 8 The actuator assembly 102 has: (a) a certain amount of clearance (i.e., play) between the movable portion 3 and the intermediate portion 40, (b) both the movable portion 3 and the intermediate portion 40 are configured to move parallel to the main axis, (c) there is no ramp interaction between the intermediate portion 40 and the movable portion 3 via the angled bearing surface, and (d) the bistable device 30 is configured to apply the biasing force directly to the movable portion 3 rather than the intermediate portion 40. It is worth noting that Figures 3 to 8 The middle portion 40 need not be bistable.

[0125] exist Figures 3 to 8 In the embodiment, the SMA elements 41, 42 (i.e., Figures 3 to 8 The actuator arrangement) is arranged to move the intermediate part 40 and (indirectly) the movable part 3 in translation in a direction perpendicular to the main axis. However, the SMA elements 41, 42 may alternatively be arranged to move the intermediate part 40 and / or the movable part 3 around the main axis (i.e., to rotate the intermediate part 40 around the main axis).

[0126] The intermediate portion 40 and the movable portion 3 are arranged to be mechanically engaged with each other, so that when the intermediate portion 40 is moved in a first direction relative to the support structure 4 by the SMA elements 41, 42 (for example, by contracting the SMA element 41), the movable portion 3 is also moved in the first direction relative to the support structure 4. The intermediate portion 40 and the movable portion 3 are arranged to be mechanically engaged with each other, so that when the intermediate portion 40 is moved in a second, opposite direction relative to the support structure 4 by the SMA elements 41, 42 (for example, by contracting the SMA element 42), the movable portion 3 is also moved in the second, opposite direction relative to the support structure 4.

[0127] A certain amount of clearance (ie play) is provided between the movable part 3 and the intermediate part 40. The amount of clearance is at least equal to the amount of displacement that the movable part 3 is configured to undergo when moving from its unstable equilibrium position to its first stable equilibrium position or second stable equilibrium position.

[0128] The first SMA element 41 is disposed on a first side of the middle portion 40, and the second SMA element 42 is disposed on a second, opposite side of the middle portion 40. The two SMA elements 41, 42 are coupled to the middle portion 40 at a first end and to the support structure 4 at a second end. However, one or both of the SMA elements 41, 42 may alternatively be coupled to the support structure 4 or the middle portion 40 at both ends and have a central portion coupled (e.g., hooked) to the other of the support structure 4 and the middle portion 40.

[0129] At least one guide support may be provided, the at least one guide support being configured to guide the movement of the movable part 3 relative to the support structure 4. At least one guide support 33 may be provided, the at least one guide support 33 being configured to guide the movement of the intermediate part 40 relative to the support structure 4.

[0130] Bistable device 30 (in Figures 3 to 8 The movable part 3 (shown as a compression spring 30) is configured to make the movable part 3 behave in a bistable manner, that is, to make the movable part 3 have a first stable equilibrium position, a second stable equilibrium position and an unstable equilibrium position between the first stable equilibrium position and the second stable equilibrium position.

[0131] The bistable device 30 may be configured to bias the moveable part 3 and the intermediate part 40 against each other to ensure that the moveable part 3 and the intermediate part 40 remain mechanically coupled to each other, but this may not be necessary, for example if the above-mentioned guide bearings are provided.

[0132] When the movable part 3 is moved to the first stable equilibrium position, for example by actuator means (indirectly via the intermediate part 40), the bistable device 30 provides a biasing force that keeps the movable part 3 in the first stable equilibrium position. Figures 3 to 6 The movable part 3 is shown to be moved from the second stable equilibrium position (ie, Figure 3 The position in the middle) moves to the first stable equilibrium position (i.e. Figure 6 position in the ).

[0133] When the movable part 3 is moved to the unstable equilibrium position, for example by actuator means (indirectly via the intermediate part 40), the biasing force of the bistable device 30 keeps the movable part 3 in the unstable equilibrium position. Figure 5 The movable part 3 is shown in an unstable equilibrium position, wherein the biasing force applied by the bistable device 30 is perpendicular to the main axis.

[0134] When the movable part 3 is moved to the second equilibrium position, for example by actuator means (indirectly via the intermediate part 40), the biasing force of the bistable device 30 keeps the movable part 3 in the second equilibrium position. Figures 6 to 8 It is shown that the movable part 3 is moved from a first stable equilibrium position towards a second stable equilibrium position by contracting the SMA element 41 and moving the intermediate part 40 to the left.

[0135] The first and second stable equilibrium positions correspond to ends of a range of movement in which the movable part 3 is arranged to be moved by actuator means relative to the support structure 4. The unstable equilibrium position may correspond to the centre of said range of movement.

[0136] The support structure 4 comprises a first end stop configured to engage the movable part 3 when the movable part 3 is in the first stable equilibrium position. The support structure 4 also comprises a second end stop configured to engage the movable part 3 when the movable part 3 is in the second stable equilibrium position.

[0137] The bistable device 30 (which can be considered as part of the biasing device, as it exerts a biasing force on the movable part 3) assists the actuator device in moving the movable part 3 relative to the support structure 4 when the movable part 3 is moved away from the unstable equilibrium position (which can also be referred to as an intermediate position) and, for example, towards the first equilibrium position or the second equilibrium position. In other words, the bistable device 30 is configured to bias the movable part 3 towards the first stable equilibrium position when the movable part 3 is moved, for example, by the actuator device, to a position between the first stable equilibrium position and the unstable equilibrium position. And the bistable device 30 is configured to bias the movable part 3 towards the second stable equilibrium position when the movable part 3 is moved, for example, by the actuator device, to a position between the second stable equilibrium position and the unstable equilibrium position. This helps, for example, to increase the stroke of the actuator device, i.e., to increase the amount by which the movable part 3 can be moved by the actuator device, and / or to improve the efficiency of the actuator device.

[0138] The actuator device (e.g., the first SMA element 41) may be configured (e.g., only) to drive the movement of the movable part 3 from the first stable equilibrium position to the first tilting position, wherein the first tilting position is a position between the unstable equilibrium position and the second stable equilibrium position, and the bistable device 30 may be configured to drive the movable part 3 from the first tilting position to the second stable equilibrium position by itself, i.e., without the driving force / force assistance from the actuator device. Similarly, the actuator device (e.g., the second SMA element 42) may be configured (e.g., only) to drive the movement of the movable part 3 from the second stable equilibrium position to the second tilting position, wherein the second tilting position is a position between the unstable equilibrium position and the first stable equilibrium position, and the bistable device 30 may be configured to drive the movable part 3 from the first tilting position to the second stable equilibrium position by itself, i.e., without the driving force / force assistance from the actuator device. In other words, the bistable device 30 may be configured to enable the movable part 3 to be moved to a position that exceeds the range of positions to which the movable part 3 can be moved by the actuator device without assistance from the bistable device. In other words, the range of positions to which the movable part 3 can be moved by the actuator device with support from the bistable device 30 may be greater than the range of positions to which the movable part 3 can be moved by the actuator device without said support from the bistable device 30.

[0139] like Fig. 9 The intermediate part 40 shown in the figure may alternatively be arranged to move perpendicular to the main axis (i.e., the axis along / around which the movable part 3 moves). In this case, the surfaces of the intermediate part 40 and / or the movable part 3 separated by a gap and configured to engage each other (e.g., surfaces 34 and 35) are each angled relative to a plane perpendicular to the main axis.

[0140] like Fig.10 A further intermediate part 50 shown in may be arranged between the intermediate part 40 and the movable part 3 , and the actuator arrangement may be configured to move the movable part 3 relative to the support structure 4 (indirectly) via the intermediate part 40 and the further intermediate part 50 .

[0141] The further intermediate part 50 may be configured to move parallel to the main axis (ie the axis along / around which the movable part 3 moves). A gap may be provided between the further intermediate part 50 and the movable part 3 instead of between the intermediate part 40 and the further intermediate part 50.

[0142] The intermediate part 40 and the further intermediate part 50 may be connected to each other via an intermediate support means 43'. The intermediate support means 43' may be configured such that when the intermediate part 40 is moved by the actuator means (ie the SMA elements 41 and 42), the further intermediate part 50 moves relative to the support structure.

[0143] The intermediate bearing device 43' comprises bearing surfaces of the intermediate portion 40 and the further intermediate portion 50, each of which is angled relative to a plane perpendicular to the main axis. The interaction between the intermediate portion 40 and the further intermediate portion 50 via the slopes of the angled bearing surfaces provides amplification of the stroke. The intermediate bearing device 43 may comprise a ball bearing between the bearing surfaces, such as Fig.10 In case the SMA elements 41 , 42 are arranged to rotate the intermediate portion 40 about the main axis, the bearing surface may be a helical bearing surface.

[0144] At least one guide bearing may be provided, which is configured to guide the movement of the further intermediate part 50 relative to the support structure 4 .

[0145] like Fig.11 As shown in , any of the above-mentioned SMA elements can be angled relative to the main axis. The SMA element can be at a non-zero acute angle to the main axis. For example, the SMA element can be arranged to apply a force to the movable part 3 having a component perpendicular to the direction of motion of the movable part 3. For example, the force applied by the SMA can help load the movable part onto a support, such as a guide support 33.

[0146] like Fig.12 As shown in , any of the above-mentioned bistable devices may include two oppositely inclined ramps forming a common peak; and may be configured to bias the movable part 3 (see biasing force F) against the inclined ramps. For example, such biasing force F may be provided by one or more elastic (or resilient) components (e.g., springs) or magnets.

[0147] like Fig.13 As shown in , the movement of the movable part 3 and / or the intermediate part 40 and / or the further intermediate part 50 relative to the support structure can, where appropriate, be guided by a pivoting lever, for example an articulated lever.

[0148] like Fig.14 and Fig.15 As shown in , any of the above-mentioned bistable devices may include one or more elastic members 30, which are configured to provide the said assistance to the actuator device. Fig.14 (and Figures 3 to 8 ), the bistable device may include a single compression spring 30. For example, Fig.15 As shown, the bistable device may include two opposing compression springs / flexures 30. Additionally or alternatively, as Fig.16 As shown, any of the above-described bistable arrangements may include one or more magnets 36, 37 configured to provide said assistance to the actuator arrangement.

[0149] Bistable flexible body

[0150] Any of the above-described bistable devices may include a bistable flexible body 310 (such as Figures 17 to 19 Those shown), the bistable flexible body 310 is configured to (directly or indirectly) make the movable part 3 bistable.

[0151] The bistable flexible body 310 is fixed at its ends to the support structure 4. The bistable flexible body 310 includes two protrusions 311 and 312 (i.e., the first protrusion 311 and the second protrusion 312) provided on a first side of the bistable flexible body 310, and two protrusions 313 and 314 (i.e., the third protrusion 313 and the fourth protrusion 314) provided on a second side of the bistable flexible body 310. The first side and the second side are opposite sides of the bistable flexible body 310 that do not overlap.

[0152] The bistable flexible body 310 is configured such that when the first protrusion 311 and the second protrusion 312 move toward each other, the bistable flexible body 310 moves to its first stable equilibrium position. The bistable flexible body 310 is configured such that when the third protrusion 313 and the fourth protrusion 314 move toward each other, the bistable flexible body 310 moves to its second stable equilibrium position.

[0153] The bistable flexible body 310 is coupled to the movable part 3 so that when the bistable flexible body 310 moves to its first stable equilibrium position, the movable part 3 also moves (directly or indirectly) to its first stable equilibrium position, and when the bistable flexible body 310 moves to its second stable equilibrium position, the movable part 3 also moves (directly or indirectly) to its second stable equilibrium position. Similarly, when the bistable flexible body 310 moves to its unstable equilibrium position, the movable part 3 also moves (directly or indirectly) to its unstable equilibrium position.

[0154] like Fig.17 As shown, the first SMA element 321 (of the actuator device) can be coupled at its ends to the first protruding portion 311 and the second protruding portion 312, so that the first SMA element 321 can drive the bistable flexible body 310 to its first stable equilibrium position by contraction. Similarly, the second SMA element 322 (of the actuator device) can be coupled at its ends to the third protruding portion 313 and the fourth protruding portion 314, so that the second SMA element 322 can drive the bistable flexible body 310 to its second stable equilibrium position by contraction.

[0155] Alternatively, if Fig.18 and Fig.19 As shown, the first SMA element 331 (of the actuator device) can be coupled to the support structure 4 at one end and to the first protruding portion 311 at the other end, the second SMA element 332 (of the actuator device) can be coupled to the support structure 4 at one end and to the second protruding portion 312 at the other end, the third SMA element 333 (of the actuator device) can be coupled to the support structure 4 at one end and to the third protruding portion 313 at the other end, and the fourth SMA element 334 (of the actuator device) can be coupled to the support structure 4 at one end and to the fourth protruding portion 314 at the other end. Contraction of both the first SMA element 331 and the second SMA element 332 will drive the bistable flexible body 310 to its first stable equilibrium position. Contraction of both the third SMA element 333 and the fourth SMA element 334 will drive the bistable flexible body 310 to its second stable equilibrium position.

[0156] It is worth noting that in Fig.18 and Fig.19 In the arrangement shown, the flexible body 310 can be driven to two other stable equilibrium positions between the first and stable equilibrium positions, so that Fig.18 and Fig.19The flexible body 310 may alternatively be referred to as a multi-stable flexible body 310. One of the other two stable equilibrium positions is between the unstable equilibrium position and the first stable equilibrium position, and the other of the other two stable equilibrium positions is between the unstable equilibrium position and the second stable equilibrium position.

[0157] Fig.19 Flexible body 310 is shown in one of these two other stable equilibrium positions.

[0158] The term "bistable flexible body" is used broadly herein to refer to any flexible body capable of having at least two stable equilibrium positions, including multistable flexible bodies.

[0159] For use with variable orifice mechanism

[0160] like Fig. 20 and Fig.21 The actuator means shown in (in this example SMA elements 41, 42) may be configured to (in this example, indirectly) rotate the movable part 3 (in this example, via the intermediate part 40) relative to the support structure 4 about the main axis P. The movable part 3 may form part of a variable aperture (e.g., variable aperture) assembly 60, which is configured such that rotation of the movable part 3 relative to the support structure 4 about the main axis P changes the aperture (size) of the variable aperture assembly 60. The main axis P may correspond to the optical axis of the variable aperture assembly 60.

[0161] Use with pop-up camera

[0162] The actuator assembly described above can be used in a pop-up camera (also known as a retractable lens camera or a telescopic camera), for example, to move one or more lenses between two stable equilibrium positions. The first equilibrium position corresponds to a retracted / folded state of the pop-up camera, for example, in which one or more lenses are configured so that they cannot focus an image on the image sensor 3 of the camera (i.e., a state in which the camera is not operational). The second equilibrium position corresponds to an extended / pop-up state, for example, in which one or more lenses are configured so that they can focus an image on the image sensor 3 of the camera (i.e., a state in which the camera is operational).

[0163] In this case, the movable part 3 will be a component comprising one or more lenses (or a lens assembly comprising one or more lenses) configured to focus an image on the image sensor of the camera. Furthermore, the principal axis (i.e. the axis along / around which the movable part 3 moves) will coincide with the optical axis of the one or more lenses / lens assembly.

[0164] When the movable part 3 is in a first equilibrium position (i.e., in a retracted / folded state), the distance along the main axis between the lens assembly / one or more lenses and the image sensor is smaller than the distance when the movable part 3 is in a second equilibrium position (i.e., in an extended / pop-up state).

[0165] A focus (eg, AF) actuator configured to drive relative movement between one or more lenses and an image sensor along a primary axis may be disposed within the pop-up camera.

[0166] B. Actuator assembly with magnets for counteracting centering forces

[0167] Fig. 22 and Fig.23 is a schematic diagram of an actuator assembly comprising a movable part 3 movable relative to a support structure 4.

[0168] The centering means 81 , 82 are configured to bias the movable part 3 towards a neutral / central stable equilibrium position.

[0169] The actuator assembly comprises an actuator device (not shown) which is configured to drive the movable part 3 away from a mid-position relative to the support structure 4 in a direction perpendicular to a main axis, which in this example is not the axis along / around which the movable part 3 moves, but is, for example, the longitudinal axis of the actuator assembly.

[0170] The biasing device comprises two magnets 72, 72' (i.e., a first magnet 72 and a second magnet 72') fixed to the support structure 4 and two target bodies 71, 71' (i.e., a first target body 71 and a second target body 71') fixed to the movable part 3. The first magnet 72 is configured to attract the first target body 71, for example, when the movable part 3 moves away from the intermediate position in a first direction D. The second magnet 72' is configured to attract the second target body 71', for example, when the movable part 3 moves away from the intermediate position in a second opposite direction.

[0171] In alternative embodiments, the magnets 72 , 72 ′ may instead be fixed to the movable part 3 , and the target bodies 71 , 71 ′ may instead be fixed to the support structure 4 .

[0172] The magnetic attraction between the magnets 72, 72' and the target bodies 71, 71' helps to counteract the centering force of the centering devices 81, 82 when the movable part 3 moves away from the intermediate position. Fig.23 As shown, the further the movable part 3 moves from the middle position in the direction D, the greater the centering force on the movable part 3, but this centering force is offset by the increase in the magnetic force between the first target body 71 and the magnet 72 because the first target body 71 and the magnet 72 are close to each other. Fig. 22and Fig.23 The biasing means assists the actuator means in moving the movable part 3 when moving the movable part 3 away from the intermediate position. This helps, for example, to increase the stroke of the actuator means, i.e. increase the amount by which the movable part 3 can be moved by the actuator means, and / or to improve the efficiency of the actuator means (e.g. by reducing the energy required to move the movable part 3 or reducing the energy required to keep the movable part 3 in a particular position away from the intermediate position).

[0173] The magnets 72, 72' and / or the target bodies 71, 71' may be electromagnets.

[0174] The movable part 3 can be moved relative to the support structure 4 across a range of movement in two orthogonal directions perpendicular to the main axis.

[0175] Fig.24 Shows that it can be Fig. 22 and Fig.23 An example of an actuator device 10 for use with an actuator assembly of . Optionally, the actuator device includes (a total of) four SMA elements (e.g., SMA wires) 11, 12, 13, 14, which are connected between the movable part 3 and the support structure 4 in the device, wherein the SMA elements 11, 12, 13, 14 can be selectively driven to move the movable part 3 relative to the support structure 4 to any position in the range of movement without applying any net torque to the movable part 3 in two orthogonal planes around the main axis.

[0176] The movable part 3 may comprise an image sensor and / or a lens assembly having an optical axis O, which may be parallel to the main axis.

[0177] The movable part 3 may comprise a display, an emitter or a part thereof. The main axis may be parallel to the general direction in which the display or emitter emits light.

[0178] SMA Components

[0179] The above-mentioned SMA actuator assembly includes at least one SMA element. The term "shape memory alloy (SMA) element" may refer to any element including SMA. The SMA element may be described as an SMA wire. The SMA element may have any shape suitable for the purposes described herein. The SMA element may be elongated and may have a circular cross section or a cross section of any other shape. The cross section may vary along the length of the SMA element. The SMA element may have a relatively complex shape, such as a spiral 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. The SMA element may be sheet-like, and such a sheet may be planar or non-planar. The SMA element may be flexible, or in other words, the SMA element may be flexible. In some examples, when connected in a straight line between two components, the SMA element can only apply tension that forces the two components together. In other examples, the SMA element may be bent around the component, and when the SMA element tends to straighten under tension, the SMA element may apply force to the component. SMA elements may be beam-shaped or rigid and may be able to apply different forces (e.g., non-tension) to the element. SMA elements may or may not include non-SMA materials and / or components. For example, an SMA element may include a core of SMA and a coating of non-SMA material. Unless the context requires otherwise, the term "SMA element" may refer to any configuration of SMA material that acts as a single actuating element, for example, the single actuating element can be individually controlled to generate a force acting on the element. For example, an SMA element may include two or more parts of an SMA material that are mechanically arranged in parallel and / or in series. In some arrangements, an SMA element may be part of a larger SMA element. Such a larger SMA element may include two or more parts that can be individually controlled, thereby forming two or more SMA elements. An SMA element may include any other configuration of an SMA wire, an SMA foil, an SMA film, or an SMA material. An SMA element may be manufactured using any suitable method, such as by a method involving drawing, rolling, deposition, sintering, or powder melting. The SMA element may exhibit any shape memory effect, such as a thermal shape memory effect or a magnetic shape memory effect, and may be controlled in any suitable manner (eg, by Joule heating, another heating technique, or by application of a magnetic field).

[0180] Variants

[0181] It will be appreciated that many other variations of the above examples are possible.

[0182] The actuator arrangement may be arranged to apply a force to the movable part in a first direction only, for example, wherein the movable part is manually movable in a second, opposite direction.

[0183] The SMA elements described above may have a significant amount of slack if desired.

[0184] The actuator devices referred to herein may be, for example, voice coil motor (VCM) actuator devices or piezoelectric actuator devices, rather than SMA actuator devices. Any suitable actuator device may be used, whether SMA or otherwise. For example, Figures 1 to 11 The SMA wire shown in any of the embodiments may be replaced with a different actuator configured to apply a force in the same direction as the force applied by the SMA.

[0185] The actuator assemblies described herein may be used in many applications, such as: autofocus, zoom, haptics, optical image stabilization (OIS), valves, augmented reality (AR), and the like.

Claims

1. An actuator assembly, comprising: Removable parts; Support structure; a primary axis, the primary axis being defined relative to the support structure; an actuator arrangement configured to move the movable portion in at least one predetermined direction relative to the support structure; and Biasing means are configured to assist the actuator means in moving the movable part in the at least one predetermined direction when moving the movable part away from the intermediate position.

2. The actuator assembly according to claim 1, wherein: The intermediate position is a position between the ends of the possible range of movement of the movable part relative to the support structure and is a position in which the movable part can be in equilibrium.

3. The actuator assembly according to claim 1 or 2, wherein: The biasing means is configured to enable the moveable part to be moved to a position outside the range of positions to which the moveable part can be moved by the actuator means without the assistance of the biasing means.

4. An actuator assembly according to any one of the preceding claims, wherein: The biasing means is configured to provide said assistance to the actuator means by exerting a force on the movable part.

5. An actuator assembly according to any one of the preceding claims, wherein: The actuator arrangement comprises at least one shape memory alloy (SMA) element.

6. An actuator assembly according to any one of the preceding claims, comprising a bistable device, the bistable device including the biasing device, and the bistable device is configured to cause the movable part to have a first stable equilibrium position, a second stable equilibrium position and an unstable equilibrium position between the first stable equilibrium position and the second stable equilibrium position; wherein the unstable equilibrium position corresponds to the intermediate position.

7. The actuator assembly according to claim 6, wherein: The first stable equilibrium position and the second stable equilibrium position correspond to ends of a possible range of movement of the movable part relative to the support structure.

8. An actuator assembly according to any one of the preceding claims, wherein: The at least one predetermined direction comprises a direction at least partially along the major axis.

9. An actuator assembly according to any one of the preceding claims, wherein: The major axis corresponds to or is parallel to a longitudinal axis of the actuator assembly.

10. An actuator assembly according to any one of the preceding claims, wherein: The movable portion includes a lens assembly configured to focus an image on an image sensor; and the principal axis corresponds to an optical axis of the lens assembly.

11. An actuator assembly according to claim 10 when dependent on claim 6, wherein: The actuator assembly is configured such that a distance between the lens assembly and the image sensor along the principal axis in the first stable equilibrium position is smaller than a distance between the lens assembly and the image sensor along the principal axis in the second stable equilibrium position.

12. An actuator assembly according to claim 10 or 11, wherein: The lens assembly includes one or more lenses; and the actuator assembly includes a focus actuator configured to drive relative movement between the one or more lenses and the image sensor along the principal axis.

13. An actuator assembly according to any one of claims 10 to 12 when dependent on claim 6, wherein: The lens assembly is arranged so that when the movable part is in the first equilibrium position, the lens assembly cannot focus an image onto the image sensor, and the lens assembly is configured so that when the movable part is in the second equilibrium position, the lens assembly can focus an image onto the image sensor.

14. An actuator assembly according to any one of the preceding claims, wherein: The actuator arrangement is configured to rotate the movable part relative to the support structure about the primary axis.

15. The actuator assembly according to claim 14 comprises a spiral support device, which supports the movable part on the supporting structure and is arranged to guide the spiral movement of the movable part around the main axis relative to the supporting structure; and wherein the spiral support device converts the rotation of the movable part around the main axis into the spiral movement of the movable part.

16. An actuator assembly according to claim 14 when dependent on any one of claims 1 to 7, wherein: The movable portion forms part of a variable aperture assembly, the variable aperture assembly being configured such that rotation of the movable portion relative to the support structure about the principal axis varies the aperture of the variable aperture assembly; and wherein the principal axis corresponds to an optical axis of the variable aperture assembly.

17. An actuator assembly according to claim 6 or any one of claims 7 to 16 when dependent on claim 6 or a claim dependent on claim 6, wherein: The bistable device is configured to bias the movable part toward the first stable equilibrium position when the movable part is between the first stable equilibrium position and the unstable equilibrium position, and the bistable device is configured to bias the movable part toward the second stable equilibrium position when the movable part is between the second stable equilibrium position and the unstable equilibrium position.

18. An actuator assembly according to claim 6 or any one of claims 7 to 17 when dependent on claim 6 or a claim dependent on claim 6, wherein: The actuator arrangement is configured to drive the movable part from the first stable equilibrium position to the second stable equilibrium position, and optionally to drive the movable part from the second stable equilibrium position to the first stable equilibrium position.

19. An actuator assembly according to claim 6 or any one of claims 7 to 18 when dependent on claim 6 or a claim dependent on claim 6, wherein: The actuator device is configured to drive the movable part from the first stable equilibrium position to a first tilting position, wherein the first tilting position is a position between the unstable equilibrium position and the second stable equilibrium position; and wherein the bistable device is capable of driving the movable part from the first tilting position to the second stable equilibrium position without assistance from the actuator device.

20. An actuator assembly according to claim 6 or any one of claims 7 to 19 when dependent on claim 6 or dependent on claim 6, wherein The actuator device is configured to drive the movable part from the second stable equilibrium position to a second tilting position, wherein the second tilting position is a position between the unstable equilibrium position and the first stable equilibrium position; and wherein the bistable device is capable of driving the movable part from the second tilting position to the first stable equilibrium position without assistance from the actuator device.

21. An actuator assembly according to any one of the preceding claims, wherein: The actuator arrangement comprises one or more shape memory alloy (SMA) elements configured to move the movable portion in the at least one predetermined direction relative to the support structure.

22. The actuator assembly of claim 21, wherein: The one or more SMA elements are coupled to the movable portion and the support structure.

23. An actuator assembly according to claim 21 or 22, wherein: The one or more SMA elements include: a first SMA element configured to drive relative movement of the movable portion in a first direction when contracted; and A second SMA element is configured to drive relative movement of the movable portion in a second opposite direction when contracted.

24. An actuator assembly according to any one of claims 1 to 23, comprising an intermediate portion movable relative to the support structure and the movable portion; and in, The actuator arrangement is configured to move the movable portion relative to the support structure by moving the intermediate portion relative to the support structure and the movable portion.

25. An actuator assembly according to claim 24 when dependent on claim 21, wherein: The one or more SMA elements are coupled to the intermediate portion and the support structure.

26. An actuator assembly according to claim 25 or claim 24, wherein: The one or more SMA elements include: a first SMA element configured to drive relative movement of the movable portion in a first direction when contracted; and A second SMA element is configured to drive relative movement of the movable portion in a second opposite direction when contracted.

27. An actuator assembly according to any one of claims 24 to 26, wherein: The intermediate portion is configured to move at least partially in a direction perpendicular to the main axis.

28. An actuator assembly according to any one of claims 24 to 26, wherein: The intermediate portion is configured to rotate about the primary axis.

29. An actuator assembly according to any one of claims 24 to 28, wherein: The one or more SMA elements are not configured to move the intermediate portion along the primary axis.

30. An actuator assembly according to any one of claims 24 to 29 when dependent on claim 6, wherein: The bistable mechanism is configured such that the intermediate portion has a first stable equilibrium position, a second stable equilibrium position, and an unstable equilibrium position between the first stable equilibrium position and the second stable equilibrium position.

31. An actuator assembly according to any one of claims 24 to 30, wherein: The intermediate part and the movable part are connected to each other via intermediate supporting means, wherein the intermediate supporting means are configured such that the movable part moves when the intermediate part is moved by the actuator means.

32. An actuator assembly according to any one of claims 24 to 30, comprising a further intermediate portion between the intermediate portion and the movable portion, in, The actuator arrangement is configured to move the movable portion relative to the support structure via the intermediate portion and the further intermediate portion.

33. An actuator assembly according to claim 32, wherein: The intermediate portion and the further intermediate portion are connected to each other via intermediate supporting means, wherein the intermediate supporting means are configured such that the further intermediate portion moves when the intermediate portion is moved by the actuator means.

34. An actuator assembly according to claim 31 or 33, wherein: The intermediate bearing means comprises a bearing surface which is angled relative to a plane perpendicular to the main axis.

35. An actuator assembly according to any one of claims 24 to 34, wherein: There is a certain amount of clearance between the moveable portion and the portion of the actuator assembly that is configured to directly move the moveable portion.

36. An actuator assembly according to claim 35, wherein: The amount of the gap is at least equal to an amount of displacement that the movable portion is configured to undergo when moving from an unstable equilibrium position to a first stable equilibrium position or a second stable equilibrium position.

37. An actuator assembly according to any one of the preceding claims, comprising at least one guide bearing configured to guide movement of the movable part relative to the support structure.

38. An actuator assembly according to claim 24, or any one of claims 25 to 37 when dependent on claim 24, comprising at least one guide support configured to guide movement of the intermediate portion relative to the support structure.

39. An actuator assembly according to claim 32 or any one of claims 33 to 38 when dependent on claim 32, comprising at least one guide support configured to guide movement of the further intermediate portion relative to the support structure.

40. An actuator assembly according to any preceding claim, comprising a pivot rod configured to guide movement of the moveable part relative to the support structure.

41. An actuator assembly according to claim 5 or any one of claims 6 to 40 when dependent on claim 5, wherein: The one or more SMA elements are parallel, perpendicular, or at an acute angle relative to the primary axis.

42. An actuator assembly according to any one of the preceding claims, wherein: The biasing means may comprise a resilient member and / or one or more magnets configured to provide said assistance to the actuator means.

43. An actuator assembly according to claim 6 or any one of claims 7 to 21 when dependent on claim 6, wherein: The bistable device includes a bistable flexible body.

44. An actuator assembly according to claim 43, wherein: The actuator device comprises: a first SMA element coupled at an end thereof to a first side of the bistable flexible body, and a second SMA element coupled at an end thereof to a second side of the bistable flexible body; The first side and the second side of the bistable flexible body are opposite sides of the bistable flexible body.

45. The actuator assembly of claim 43, wherein: The actuator device comprises: first and second SMA elements, each coupled at one end to the support structure and at another end to a first side of the bistable flexible body; and a third SMA element and a fourth SMA element, each coupled at one end to the support structure and at another end to the second side of the bistable flexible body; The first side and the second side of the bistable flexible body are opposite sides of the bistable flexible body.

46. ​​An actuator assembly according to any one of claims 1 to 5, wherein: The intermediate position is a stable equilibrium position.

47. An actuator assembly according to claim 46, comprising a centering device configured to bias the movable part towards the intermediate position.

48. An actuator assembly according to claim 46 or 47, wherein: The biasing means comprises one or more magnets configured to provide said assistance to the actuator means.

49. An actuator assembly according to any one of claims 46 to 48, wherein: The movable part is movable within a range of movement in two orthogonal directions perpendicular to the main axis relative to the support structure; and wherein the at least one predetermined direction includes a direction in a plane of the two orthogonal directions.

50. The actuator assembly of claim 49, wherein: The actuator arrangement comprises four SMA elements connected between the movable part and the support structure in an arrangement in which the SMA elements can be selectively driven to move the movable part relative to the support structure to any position within the range of movement without applying any net torque to the movable element in two orthogonal planes about the main axis.

51. An actuator assembly according to any one of claims 46 to 50, wherein: The movable portion includes an image sensor and / or a lens assembly.

52. An actuator assembly according to any one of the preceding claims, wherein: The movable portion includes a display, a transmitter or a portion thereof.

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