SMA actuator assembly

Abstract

An SMA actuator assembly comprising: a support structure; a camera module supported on the support structure in a manner that allows the camera module to tilt relative to the support structure about two orthogonal tilt axes, where the camera module comprises an image sensor and a lens assembly arranged to focus an image onto the image sensor; two or more SMA wires arranged to tilt the camera module relative to the support structure about two orthogonal tilt axes; and a control circuit configured to apply a driving signal to the two or more SMA lines so as to drive the camera module to tilt between a plurality of predetermined positions in a repeating pattern with respect to the support structure.

Description

[0001] Field

[0002] This application relates to an SMA actuator assembly, particularly an SMA actuator assembly for tilting or moving (such as shifting or translating) a movable component (such as a camera module) between predetermined positions in a repetitive pattern relative to a support structure, for example for achieving super-resolution imaging or wobulation of an image.

[0003] Background

[0004] There is a desire to improve the quality of images from miniature cameras (such as those incorporated in laptop computers). The space available for such miniature cameras is very limited, and the size of such miniature cameras is limited in size to only a few millimeters in the lateral direction perpendicular to the camera optical axis (e.g., along the y-axis).

[0005] There is also a desire to improve the resolution of projected or otherwise displayed images and to improve the filling of pixels in such images through wobulation. Small size and low power consumption are key requirements for many applications such as AR light engines.

[0006] Summary

[0007] According to one aspect of the present utility model, there is provided an SMA actuator assembly, comprising: a support structure; a movable component supported on the support structure in such a way that:

[0008] - allows the movable component to tilt relative to the support structure about one or more axes of movement; and / or

[0009] - allows the movable component to move relative to the support structure along one or more axes of movement.

[0010] The SMA actuator assembly includes: one or more SMA wires arranged to tilt the movable component relative to the support structure about one or more axes of movement and / or to move the movable component relative to the support structure along one or more axes of movement; and a control circuit configured to apply drive signals to the one or more SMA wires so as to cause the movable component to tilt relative to the support structure about one or more axes of movement between a plurality of predetermined positions in a repetitive pattern and / or the movable component to move relative to the support structure along one or more axes of movement between a plurality of predetermined positions in a repetitive pattern.

[0011] The SMA actuator assembly is dimensionally compact. The high energy density of the SMA wire allows for rapid actuation with high actuation force combined with relatively small space requirements. Additionally, tilting in a repeating pattern allows the SMA actuator assembly to achieve super-resolution imaging or micro-oscillation, depending on the device or optical element combined with the SMA actuator assembly. By restricting the driving scheme of the SMA wire to a predetermined pattern, the control circuit can be relatively simple and thus compact. In the case of employing tilting, the tilting motion driven by the SMA wire particularly reduces the size of the movement envelope required for effective super-resolution imaging or micro-oscillation with the SMA wire, thus working in concert with the compact SMA wire to allow for an even more compact SMA actuator assembly.

[0012] According to the present utility model, there is also provided an SMA actuator assembly, comprising: a support structure; a movable member supported on the support structure in a manner that allows the movable member to tilt relative to the support structure about one or more movement axes (also referred to as one or more tilting axes) and / or allows the movable member to move along one or more movement axes (or tilting axes); and one or more SMA wires arranged to cause the movable member to tilt relative to the support structure about one or more movement axes and / or to cause the movable member to move along one or more movement axes. The movable member may be a camera module.

[0013] In some embodiments, the SMA actuator assembly includes a control circuit configured to apply a drive signal to one or more SMA wires so as to cause the movable member to tilt relative to the support structure about one or more movement axes between a plurality of predetermined positions in a repeating pattern and / or to cause the movable member to move along one or more movement axes relative to the support structure between a plurality of predetermined positions in a repeating pattern. The predetermined positions may also be referred to as predetermined orientations. Each predetermined position / orientation may be defined by a specific angular position or angular orientation of the movable member relative to the support structure. An image sensor may be configured to capture an image at each predetermined position.

[0014] In some embodiments, the movable member includes an optical device comprising a lens assembly defining an optical axis, wherein one or more movement axes are perpendicular to the optical axis. The optical device may be a camera module including an image sensor, wherein the lens assembly is arranged to focus an image onto the image sensor.

[0015] In some embodiments, the control circuit is configured to apply a drive signal to two or more SMA wires for achieving super-resolution imaging using the camera module. Thus, the predetermined position or orientation may be such that when the movable member tilts or moves from one of the predetermined positions to the next predetermined position, the image focused onto the image sensor by the lens assembly is shifted by a sub-pixel distance. The sub-pixel distance is a distance smaller than the pixel pitch of the image sensor.

[0016] In some embodiments, the SMA actuator assembly includes a projector for projecting an image, wherein the movable member includes at least a portion of the projector such that tilting or movement of the movable member relative to the support structure causes the projected image to move. The control circuit may be configured to apply drive signals to one or more SMA wires to effect micro - pendulation of the projected image.

[0017] In some embodiments, the movable member includes a display panel for displaying an image. The control circuit may be configured to apply drive signals to one or more SMA wires to effect micro - pendulation of the displayed image.

[0018] In some embodiments, a plurality of predetermined positions in the repeating pattern are arranged in two degrees of freedom. For example, the predetermined positions may be arranged in a square. The movable member does not need to stop at the predetermined positions but may continuously move through the predetermined positions.

[0019] In some embodiments, the control circuit is configured to apply drive signals to one or more SMA wires so as to cause the movable member to tilt between a plurality of predetermined positions relative to the support structure in a repeating pattern about two orthogonal tilting axes, and wherein one or more SMA wires include four SMA wires, optionally, a total of four SMA wires are in an arrangement capable of applying torque to the movable member about an axis perpendicular to the two orthogonal tilting axes.

[0020] In some embodiments, two of the four SMA wires are arranged to apply torque to the movable member in a first direction, while the other two SMA wires are arranged to apply torque to the movable member in an opposite second direction.

[0021] In some embodiments, the four SMA wires are arranged in a ring at different angular positions about an axis perpendicular to the two orthogonal tilting axes, and the successively arranged SMA wires are arranged to apply forces to the movable member in alternating directions.

[0022] In some embodiments, the four SMA wires are arranged such that corresponding subsets of two SMA wires are arranged to apply forces to the movable member in four corresponding directions along the two orthogonal tilting axes.

[0023] In some embodiments, the four SMA wires include two pairs of SMA wires, and when viewed perpendicular to the two orthogonal tilting axes, each pair of SMA wires is arranged on opposite sides of the movable member.

[0024] In some embodiments, when viewed perpendicular to the two orthogonal tilting axes, the SMA wires in each pair of SMA wires cross or overlap.

[0025] In some embodiments, four SMA wires are arranged to apply forces on a movable member in angular directions offset from each other by 90 degrees.

[0026] In some embodiments, one or more SMA wires include two or more SMA wires that are arranged parallel to one or more movement axes, optionally arranged in a plane.

[0027] In some embodiments, one or more SMA wires are arranged at an angle relative to one or more movement axes.

[0028] In some embodiments, the control circuit is configured to apply a drive signal to one or more SMA wires to cause the movable member to tilt or move between a plurality of predetermined positions at a predetermined frequency.

[0029] In some embodiments, the resonance frequency at which the movable member tilts about one or more movement axes or the movable member moves along one or more movement axes is substantially equal to the predetermined frequency, particularly differing from the predetermined frequency by less than 10%, preferably less than 5% or less than 1%.

[0030] In some embodiments, the SMA actuator assembly includes a first elastic element, wherein one or more SMA wires include a first SMA wire that is configured to deform the first elastic element upon contraction, and wherein the first elastic element is configured to oscillate at a first frequency to cause the movable member to tilt or move between at least some of the predetermined positions. The first frequency may be the resonance frequency of the first elastic element in the direction of deformation by the first SMA wire. The first SMA wire may be driven at the first frequency.

[0031] In some embodiments, the SMA actuator assembly includes a second elastic element, wherein one or more SMA wires include a second SMA wire that is configured to deform the second elastic element upon contraction, and wherein the second elastic element is configured to oscillate at a second frequency to cause the movable member to tilt or move between at least some of the predetermined positions. The second frequency may be the resonance frequency of the second elastic element in the direction of deformation by the second SMA wire. The second SMA wire may be driven at the second frequency.

[0032] In some embodiments, the first elastic element is configured to tilt or move the movable member about or along a first axis, and the second elastic element is configured to tilt or move the movable member about or along a second axis perpendicular to the first axis. The first frequency may be substantially equal to the second frequency. The first SMA wire may be driven at the same frequency as the second SMA wire. The phase difference between the drive signal applied to the first SMA wire and the drive signal applied to the second SMA wire may be 90 degrees.

[0033] In some embodiments, the SMA actuator assembly includes a support device that allows the movable member to tilt relative to the support structure about one or more axes of movement and / or the movable member to move relative to the support structure along one or more axes of movement.

[0034] In some embodiments, the support device is configured to allow the movable member to tilt relative to the support structure about two orthogonal axes of tilt, wherein the support device is arranged to constrain translational movement of the movable member along the two orthogonal axes of tilt, and optionally, wherein the support device is further arranged to constrain translational movement and / or rotational movement of the movable member along and / or about an axis perpendicular to the two orthogonal axes of tilt.

[0035] In some embodiments, the support device is arranged to constrain movement of the movable member along the two orthogonal axes of tilt by forces applied to the movable member by two or more SMA wires at positions offset along an axis perpendicular to the two orthogonal axes of tilt.

[0036] In some embodiments, the support device includes a sheet or flexure connected between the support structure and the movable member, and optionally, wherein the sheet or flexure extends in a plane defined by one or more axes of movement.

[0037] In some embodiments, the support device includes a pivot or a sliding bearing, particularly a spherical sliding bearing, or wherein the support device includes a flexible block material such as rubber.

[0038] In some embodiments, the SMA actuator assembly is configured to tilt or move the movable member such that at least a portion of the movable member moves in a loop when viewed along a major axis perpendicular to one or more axes of movement, and optionally, wherein the loop is an ellipse, and optionally, wherein the loop is a circle.

[0039] In some embodiments, the support device is configured to guide at least a portion of the movable member to move in a loop when viewed along a major axis perpendicular to one or more axes of movement, and optionally, wherein the loop is an ellipse, and optionally, wherein the loop is a circle.

[0040] In some embodiments, one or more SMA wires are configured to drive at least a portion of the movable member to move along the major axis in a first direction when contracting, and wherein the actuator assembly includes a biasing device configured to cause at least a portion of the movable member to move along the major axis in a second direction opposite to the first direction, and wherein the support device converts the movement of at least a portion of the movable member along the major axis into movement along a loop.

[0041] In some embodiments, the support device is configured to guide at least a portion of the movable member along a helical path about a main axis.

[0042] In some embodiments, one or more SMA wires include a total of one SMA wire that causes the movable member to tilt or move between a plurality of predetermined positions.

[0043] According to the present invention, there is also provided an SMA actuator assembly, comprising: a support structure; a movable member supported on the support structure in a manner that allows the movable member to tilt relative to the support structure about two orthogonal tilt axes; two or more SMA wires arranged to cause the movable member to tilt relative to the support structure about two orthogonal tilt axes; and a control circuit configured to apply drive signals to the two or more SMA wires to drive the movable member to tilt between a plurality of predetermined positions relative to the support structure in a repeating pattern.

[0044] In some embodiments, the movable member includes an optical device, the optical device including a lens assembly defining an optical axis, wherein the two orthogonal tilt axes are perpendicular to the optical axis.

[0045] In some embodiments, the optical device is a camera module including an image sensor, wherein the lens assembly is arranged to focus an image onto the image sensor.

[0046] In some embodiments, the control circuit is configured to apply drive signals to the two or more SMA wires for achieving super-resolution imaging of the camera module.

[0047] In some embodiments, the SMA actuator assembly includes a projector for projecting an image, wherein the movable member includes at least a portion of the projector such that tilting of the movable member relative to the support structure moves the projected image.

[0048] In some embodiments, the control circuit is configured to apply drive signals to the two or more SMA wires for achieving micro-swing of the projected image.

[0049] In some embodiments, the movable member includes a display panel for displaying an image.

[0050] In some embodiments, the control circuit is configured to apply drive signals to the two or more SMA wires for achieving micro-swing of the displayed image.

[0051] In some embodiments, the predetermined positions in the repeating pattern are arranged in two degrees of freedom.

[0052] In some embodiments, two or more SMA wires include four SMA wires. Optionally, a total of four SMA wires are in an arrangement capable of applying torque to a movable component about an axis perpendicular to two orthogonal tilt axes.

[0053] In some embodiments, two of the four SMA wires are arranged to apply torque to the movable component in a first direction, while the other two SMA wires are arranged to apply torque to the movable component in an opposite second direction.

[0054] In some embodiments, the four SMA wires are arranged in a ring at different angular positions about the axis, and the successively arranged SMA wires are arranged to apply forces to the movable component in alternating directions.

[0055] In some embodiments, the four SMA wires are arranged such that corresponding subsets of two SMA wires are arranged to apply forces to the movable component in four corresponding directions along two orthogonal tilt axes.

[0056] In some embodiments, the four SMA wires include two pairs of SMA wires, and when viewed perpendicular to the two orthogonal tilt axes, each pair of SMA wires is arranged on opposite sides of the movable component.

[0057] In some embodiments, when viewed perpendicular to the two orthogonal tilt axes, the SMA wires in each pair cross or overlap.

[0058] In some embodiments, the four SMA wires are arranged to apply forces to the movable component in angular directions offset from each other by 90 degrees.

[0059] In some embodiments, two or more SMA wires are arranged parallel to two orthogonal tilt axes, optionally arranged in a plane.

[0060] In some embodiments, two or more SMA wires are arranged at an angle with respect to two orthogonal tilt axes.

[0061] In some embodiments, the control circuit is configured to apply drive signals to two or more SMA wires to drive the movable component to tilt between a plurality of predetermined positions at a predetermined frequency.

[0062] In some embodiments, the resonance frequency at which the movable component tilts about two orthogonal tilt axes is substantially equal to the predetermined frequency, particularly differing from the predetermined frequency by less than 10%, preferably less than 5% or less than 1%.

[0063] Some embodiments further include a support device that allows the movable component to tilt relative to the support structure about two orthogonal tilt axes.

[0064] In some embodiments, the support device is arranged to constrain translational movement of the movable member along two orthogonal inclined axes, and optionally, wherein the support device is further arranged to constrain translational movement and / or rotational movement of the movable member along and / or about an axis perpendicular to the two orthogonal inclined axes.

[0065] In some embodiments, the support device is arranged to constrain movement of the movable member along two orthogonal inclined axes by forces applied to the movable member by two or more SMA wires at positions offset along an axis perpendicular to the two orthogonal inclined axes.

[0066] In some embodiments, the support device includes a sheet or flexure connected between the support structure and the movable member, and optionally, wherein the sheet or flexure extends in a plane defined by the two orthogonal inclined axes.

[0067] In some embodiments, the support device includes a pivot or a sliding bearing, particularly a spherical sliding bearing, or wherein the support device includes a flexible block material such as rubber. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Certain embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0070] Figure 1A and Figure 1B are a schematic perspective view and a cross-sectional view of an SMA actuator assembly according to an embodiment of the present invention;

[0071] Figure 2A and 2B are a perspective view and a cross-sectional view of an SMA actuator assembly according to an embodiment of the present invention;

[0072] Figure 3A and 3B are a plan view and a side view of an SMA actuator assembly according to an embodiment of the present invention;

[0073] Figure 4 is a side view of an SMA actuator assembly according to an embodiment of the present invention;

[0074] Figure 5 is a plan view of an SMA actuator assembly according to an embodiment of the present invention; and

[0075] Figures 6A - 6D is a schematic diagram illustrating a specific method for implementing super-resolution imaging or a micro-pendulum.

[0076] DETAILED DESCRIPTION

[0077] Figures 1A - 1B and Figures 2A - 2BSchematically shown is an SMA actuator assembly 1 according to the present utility model. The SMA actuator assembly 1 includes a support structure 10 and a movable member 20. The movable member 20 is supported on the support structure 10 in a manner that allows the movable member 20 to tilt relative to the support structure 10 about two orthogonal inclined axes (the x-axis and the y-axis in the depicted embodiment). In some embodiments, the SMA actuator assembly 1 includes a support device 40 that allows the movable member 20 to tilt relative to the support structure 10 about two orthogonal inclined axes x, y.

[0078] Although the movement of the movable member 20 is described herein with reference to the static support structure 10, it should be recognized that this movement is only relative. The support structure 10 does not have to be static and can itself move within the device in which the SMA actuator assembly 1 is incorporated or as part of such a device.

[0079] The SMA actuator assembly 1 includes two or more SMA wires 30. The SMA wires 30 are arranged to tilt the movable member 20 relative to the support structure 10 about two orthogonal inclined axes x, y.

[0080] The SMA actuator assembly 1 further includes a control circuit (not shown) configured to apply drive signals to two or more SMA wires 30 to drive the movable member 20 to tilt relative to the support structure 10. The control circuit drives such tilting between a plurality of predetermined positions in a repeating pattern. Reference Figures 3A - 3B describes an exemplary drive scheme that can be implemented by the control circuit.

[0081] For example, the control circuit can apply PWM (pulse width modulated) control signals to the SMA wires 30. Supplying power to the SMA wires 30 heats the SMA wires 30. When the transition temperature is reached, the SMA wires 30 begin to contract. The magnitude and / or frequency of the SMA wire contraction can be controlled by supplying appropriate PWM control signals, thereby allowing selective and targeted contraction of the SMA wires 30 in the arrangement to precisely move / tilt the movable member 20 relative to the support structure 10.

[0082] Move in a repeating pattern

[0083] The control circuit drives the tilting between a plurality of predetermined positions in a repeating pattern. Such tilting between a plurality of predetermined positions in a repeating pattern can be used in various applications, such as to achieve super-resolution imaging or a micro pendulum.

[0084] The predetermined positions in the repeating pattern can be at least two positions. Thus, the movable member 20 can move repeatedly between two predetermined positions. The predetermined positions in the repeating pattern can be four (or more) positions.

[0085] Preferably, the predetermined positions in the repeating pattern can be arranged in two degrees of freedom. For example, the predetermined positions can form a square. Generally, the predetermined positions can form a triangle, pentagon, hexagon, or any other regular shape. The predetermined positions can be located along an annular (e.g., elliptical (e.g., circular) path).

[0086] The predetermined positions can be stationary positions, so that the movable member 20 can stop at each predetermined position before moving to the next predetermined position. Alternatively, the movable member 20 can move continuously between multiple predetermined positions, e.g., move continuously along a predetermined continuous path.

[0087] Super-resolution imaging

[0088] In some embodiments, the movable member 20 includes an optical device. The optical device can, for example, include a lens assembly that defines an optical axis. Two orthogonal tilt axes x-y are perpendicular to the optical axis.

[0089] Reference Figure 1A , the optical device can be a camera module 21. The camera module 21 includes an image sensor and a lens assembly. The lens assembly is arranged to focus an image onto the image sensor.

[0090] The control circuit can be configured to apply a drive signal to the SMA wire 30 for achieving super-resolution imaging using the camera module 21. In particular, the control circuit drives the movable member to move between multiple predetermined positions in a repeating pattern, which in turn causes the image on the image sensor to move between multiple predetermined image positions in the repeating pattern. The image on the image sensor can, for example, move a sub-pixel distance between multiple predetermined image positions. Thus, super-resolution imaging can be achieved, for example, by combining two or more images captured at positions offset from each other by a sub-pixel distance.

[0091] For this purpose, the movable member 20 can be controllably moved / tilted between multiple predetermined positions offset from each other such that the image on the image sensor moves a sub-pixel distance in a direction parallel to the photosensitive area of the image sensor. Thus, the light that falls on the pixel center at one position (and can thus be used to capture an image) falls between pixels at another position. The control circuit can drive the SMA wire 30 to controllably move the movable member 20 in this way. The sub-pixel distance is a distance less than the pixel pitch of the photosensitive area of the image sensor. The pixel pitch refers to the distance between the centers of two adjacent pixels.

[0092] The movable component can be controllably moved such that the image on the image sensor is moved with a positional accuracy of 0.5 μm or less. Particular advantages are achieved in cases where the actuator device includes a plurality of SMA wires, since SMA provides a high actuating force compared to other forms of actuator. This can contribute to the precise positioning of the movable component relative to the support structure.

[0093] The predetermined positions can be offset from each other in the direction of the pixel rows and / or along the pixel columns of the photosensitive region of the image sensor. The predetermined positions can include: i) one or more positions offset from the starting position by a sub-pixel distance along the pixel rows, and ii) one or more positions offset from the starting position by a sub-pixel distance along the pixel columns. Optionally, the two or more positions can include one or more positions offset from the starting position by a sub-pixel distance along the pixel rows and along the pixel columns.

[0094] An image is captured at each predetermined position using the image sensor. A controller can control the image sensor to capture the image. The controller can be implemented as part of a control circuit or part of another circuit. Alternatively, the controller can be implemented as part of a processor forming part of a portable electronic device.

[0095] Then, for example using the processor of the portable electronic device or the above-mentioned controller, the images can be combined to form a super-resolution image. The resolution of the super-resolution image is greater than the resolution of the individual images captured by the image sensor. For example, two or more images can be combined by interleaving two or more images.

[0096] Micro pendulum

[0097] Reference Figure 2B , the SMA actuator assembly 1 can include a projector 22. The projector 22 can project an image. The movable component 20 includes at least a part of the projector 22 such that the inclination of the movable component 20 relative to the support structure 10 moves the projected image. For example, the movable component 20 can include a light-emitting element (such as a laser or a laser array) or a light-modifying element (such as a diffraction grating or a reflective element). In either case, the movement of the movable component 20 can move the projected image.

[0098] The control circuit is configured to apply drive signals to two or more SMA lines 30 to effect micro - sway of the projected image. In this regard, micro - sway can be implemented in substantially the same synonymous manner as described for reference super - resolution imaging. The difference is that instead of using an image sensor to capture images at each predetermined position, the projector can project images at each predetermined position. The images projected at each predetermined position can be low - resolution images formed from subsets of pixels of a high - resolution image. Thus, a high - resolution image can be effectively segmented into multiple low - resolution images projected in quick succession. The movable member 20 can move between multiple predetermined positions in a repeating pattern at a frequency greater than 30 Hz, preferably greater than 60 Hz, and further preferably greater than 120 Hz, such that the human eye perceives the successive low - resolution images as a single high - resolution image.

[0099] Instead of providing a projector, the movable member 20 can include a display panel for displaying images. The control circuit can be configured to apply drive signals to two or more SMA lines to effect micro - sway of the displayed image.

[0100] Arrangement of the SMA lines 30

[0101] Figures 1A - 1B and Figures 2A - 2B depicts two possible embodiments of the arrangement of the SMA lines 30 for driving the movable member 20 to tilt relative to the support structure 10. These arrangements of the SMA lines 30 are particularly compact and are thus particularly suitable for applications with limited space constraints. Generally, any other arrangement of the SMA lines 30 that can cause the movable member 20 to tilt relative to the support structure can be used.

[0102] Generally, at least two SMA lines 30 are provided to allow tilting in at least two degrees of freedom. The two SMA lines 30 can be opposed by an elastic element (such as a spring).

[0103] Preferably, the SMA actuator assembly 1 includes at least three SMA lines 30. This allows control of the tension in the SMA lines 30 (as a third degree of freedom), thereby allowing more precise movement control of the movable member 20, which is particularly beneficial for the purposes of implementing super - resolution imaging and micro - sway.

[0104] As Figures 1A - 1B and Figures 2A - 2B shown, the SMA actuator assembly 1 can include four SMA lines 30, preferably a total of four SMA lines 30. This allows a more symmetric arrangement of the SMA lines 30, thereby allowing more precise and reliable motion control with less complexity in the drive scheme.

[0105] The SMA wires 30 can be connected between the movable member 20 and the support structure 10. One end of each SMA wire 30 can be connected to the movable member 20 through a connecting element 23 (such as a movable crimp). The other end of each SMA wire 30 can be connected to the support structure 10 through a connecting element 13 (such as a static crimp). Alternatively, for example, the SMA wires 30 can be connected to the support structure 10 or the movable member 20 at both ends and hooked around the contact portion with the movable member 20 or the support structure 10. Further alternatively, an intermediate mechanism can be provided between the SMA wires 30 and the movable member 20 and / or the support structure 10 to transmit the force exerted by the contraction of the SMA wires 30.

[0106] The SMA wires 30 can be in the arrangement as described in WO 2013 / 175197 A1 (which is incorporated herein by reference). Thus, the SMA wires 30 can be in an arrangement capable of applying a torque to the movable member 20 about an axis z perpendicular to two orthogonal inclined axes x, y. This allows the torque about the axis z to be controlled by the SMA wires 30, for example to reduce or mitigate the rotation about the axis z. Such an SMA wire arrangement may not require a support device that restricts the rotation about the axis z, thereby allowing the SMA actuator assembly 1 to be manufactured more compactly.

[0107] Two of the four SMA wires can be arranged to apply a torque to the movable member 20 in a first direction (e.g., clockwise direction), similar to Figure 1A the SMA wires 30 connected to the upper right and lower left corners of the movable member 20. The other two SMA wires 30 can be arranged to apply a torque to the movable member 20 in an opposite second direction (e.g., counterclockwise direction), similar to Figure 1A the SMA wires 30 connected to the upper left and lower right corners of the movable member 20. In other words, the four SMA wires 30 can be arranged in a ring at different angular positions around the axis, and the sequentially arranged SMA wires are arranged to apply forces to the movable member in alternating directions.

[0108] In addition, the four SMA wires can be arranged such that the corresponding subsets composed of two SMA wires are arranged to apply forces to the movable member in four corresponding directions along two orthogonal inclined axes x, y. For example, the two SMA wires 30 provided on the Figure 1A left side can apply forces in the -x direction, while the two SMA wires 30 provided on the Figure 1A right side can apply forces in the +x direction. The two SMA wires 30 connected to the Figure 1A top of the movable member 20 in Figure 1ATwo SMA wires 30 at the bottom of the movable part 20 in [the device] can apply force in the +y direction. This provides a symmetric and balanced arrangement of the SMA wires, making movement control simpler and more precise.

[0109] Generally, when observed perpendicular to two orthogonal inclined axes x - y (and thus when observed along the z - axis), the arrangement of the SMA wires 30 can be rotationally symmetric. This can achieve the benefits of a symmetric and balanced arrangement of the SMA wires that makes movement control simpler and more precise.

[0110] As Figure 1A shown, the four SMA wires 30 can include two pairs of SMA wires. When observed perpendicular to two orthogonal inclined axes x - y (and thus when observed along the z - axis), each pair of SMA wires can be arranged on opposite sides of the movable part 20. This allows the SMA actuator assembly 1 to be more compact along one of the orthogonal axes (here along the y - axis), which is particularly useful in applications such as laptop cameras. When observed perpendicular to two orthogonal inclined axes x - y, the SMA wires 30 of each pair can cross or overlap. This allows the SMA wires 30 to be made longer compared to a situation where such overlap is not allowed (for a given orientation of the SMA wires). The SMA wires in each pair can be offset along the z - axis to avoid direct physical contact or rubbing against each other when the wires contract.

[0111] As Figure 1A and Figure 2A shown, the four SMA wires 30 can be arranged to apply forces to the movable part in angular directions offset from each other by 90 degrees. The SMA wires 30 can extend in angular directions offset from each other by 90 degrees. This provides a particularly balanced arrangement of the SMA wires.

[0112] The SMA wires 30 can be arranged parallel to two orthogonal inclined axes x - y, optionally arranged in a plane. This can reduce the size of the SMA actuator assembly in a direction perpendicular to the orthogonal inclined axes x - y (and thus along the z - axis). Support means for constraining the movement of the movable part 20 along the z - axis may not be required.

[0113] Therefore, as Figure 1A and Figure 1B shown, the SMA wires 30 can be mounted on the top of the camera module 21. In this design, the SMA wires 30 are located in a plane perpendicular to the optical axis and are 90 degrees relative to each other. These wires are slightly separated along the z - axis such that the wires can cross without touching. These wires are 90 degrees relative to each other such that the lines of force generated by these wires are all orthogonal. This is preferred (but not required) because it increases the symmetry of the actuator movement.

[0114] Similarly, as Figure 2A andFigure 2B As shown, the SMA wire 30 is mounted on top of the projector 22. In this design, the wire lies in a plane perpendicular to the optical axis and is in the SMA wire arrangement described in WO 2013 / 175197 A1.

[0115] Alternatively, two or more SMA wires may be arranged at an angle with respect to two orthogonal tilting axes. For example, this may be particularly useful when providing a sliding or rolling bearing, as the angled SMA wires can bias the movable part 20 against the sliding or rolling bearing. Thus, the SMA wires can slope down from the movable part 20 to the support structure. In this case, it is advantageous to have a bearing constraint that prevents the camera module 21 from moving in the -z direction.

[0116] Bearing device 40

[0117] The SMA actuator assembly 1 may also include a bearing device 40. The bearing device 40 allows the movable part 20 to tilt relative to the support structure 10 about two orthogonal tilting axes x, y.

[0118] The bearing device 40 is arranged to constrain translational movement of the movable part 20 along two orthogonal tilting axes. Thus, translational movement of the movable part 20 along the x-axis or y-axis can be reduced or even prevented.

[0119] Optionally, the bearing device is also arranged to constrain translational movement and / or rotational movement of the movable part 20 along and / or about an axis z perpendicular to the two orthogonal tilting axes x-y.

[0120] As Figure 1B and Figure 2B shown, the bearing device 40 is arranged to constrain movement of the movable part 20 along two orthogonal tilting axes at a position offset along an axis z perpendicular to the two orthogonal tilting axes x-y due to the force exerted on the movable part 20 by two or more SMA wires 30.

[0121] Figure 1B and Figure 2B shows a bearing device 40 in the form of a sheet or flexure. The sheet or flexure is connected between the support structure 10 and the movable part 20. The sheet or flexure spans the gap between the support structure 10 and the movable part 20.

[0122] In particular, the sheet or flexure extends along one or both of the two orthogonal tilting axes x-y. The sheet or flexure may be flat, i.e., having a smaller extent along the z-axis compared to the x-axis or y-axis. The sheet or flexure may extend substantially in the plane defined by the two orthogonal tilting axes x-y.

[0123] Thus, inFigure 1B In the design, the camera module 21 is restricted from moving along the x-axis and y-axis by a sheet or flexure that is connected to both the camera module 21 and the support structure 10 at the bottom of the camera module 21. The sheet or flexure can be an FPC or a PCB (on which the image sensor of the camera module 21 is mounted), or can be an additional component such as a stainless steel plate.

[0124] Similarly, as Figure 2B shown, the projector 22 is restricted from moving along the x-axis and y-axis by a sheet or flexure that is connected to the projector 22 and the support structure 10 at the bottom of the projector 22. The sheet or flexure can be implemented by an FPC or a PCB on which the light-emitting elements are mounted, or can be an additional component such as a stainless steel plate.

[0125] Although Figure 1B and Figure 2B the support device 40 in

[0126] is implemented by a flexure, many other suitable support devices 40 are available. For example, the support device 40 can include a pivot point around which a movable member pivots to tilt around two orthogonal axes x-y. The support device 40 can include a sliding support, such as a spherical sliding support, such as a ball. The center of the sphere or the ball can be at the intersection of the two orthogonal tilt axes x-y.

[0127] Further alternatively, the support device 40 can include a flexible block material, such as rubber.

[0128] Thus, in any variation of the above designs, the flexure or sheet can be replaced by a pivot or a support that provides lateral restraint. In another variation, the flexure can be replaced by a rubber or flexible material placed under the camera module 21 or the projector. This material can also be used to affect the resonance frequency.

[0129] Resonance design

[0130] In some embodiments of the present invention, the SMA wires not only drive the tilt of the movable member 20, but also act as springs that cause resonant motion at a desired frequency.

[0131] In this regard, the control circuit can be configured to apply drive signals to two or more SMA wires to drive the movable member to tilt between a plurality of predetermined positions in a repeating pattern at a predetermined frequency.

[0132] The resonance frequencies at which the movable member tilts about two orthogonal tilt axes can be substantially equal to the predetermined frequency. Thus, the resonance frequency can differ from the predetermined frequency by less than 10%, preferably less than 5% or less than 1%.

[0133] The resonance frequency of the SMA actuator assembly can be affected by the diameter, length of the SMA wires, the height of the wires from the orthogonal tilt axes, the stiffness of the support means (e.g., flexures), and the moment of inertia of the movable member (in use, thus together with a part of a camera module or a projector, etc.). By appropriately selecting these parameters, the SMA actuator assembly can be at or near the resonance frequency at the desired motion frequency. This can reduce the power consumption of the SMA actuator assembly as the force input required to drive the movement of the movable member between the plurality of predetermined positions is reduced.

[0134] Reference Figure 3A and Figure 3B discloses another embodiment. Figure 3A is a plan view of the actuator assembly along axis P, and Figure 3B is a side view of the actuator assembly.

[0135] In Figure 3A and Figure 3B In the illustrated embodiment, the SMA actuator assembly 1 includes a support structure (not shown) and a movable member 20 indicated by the dashed lines. The movable member 20 is supported on the support structure 10 in a manner that allows the movable member 20 to tilt relative to the support structure about two orthogonal tilt axes (the x-axis and the y-axis in the depicted embodiment). In some embodiments, the SMA actuator assembly 1 includes support means that allow the movable member 20 to tilt about two orthogonal tilt axes x, y relative to the support structure. The movable member 20 can pivot about a point 50, for example (as Figure 3B shown), which point 50 is located at the intersection between the two tilt axes.

[0136] The movable member 20 includes a lens assembly 52 and an image sensor 54. The lens assembly 52 includes one or more lenses and is arranged to focus an image onto the image sensor 54.

[0137] The assembly 1 includes an SMA wire 30 that causes the movable member 20 to tilt about one of the two axes (in Figure 3A and Figure 3BIn the case of the illustrated embodiment, it is inclined with respect to the x-axis). One end of the SMA wire 30 is connected to the movable member 20 through a connecting element 23 (such as a movable crimping member). The other end of the SMA wire 30 is connected to the support structure through a connecting element 13 (such as a static crimping member). The assembly 1 further includes an elastic element, in particular a spring 56, which is connected to the movable member 20 at one end, for example connected to the connecting element 23 or connected via other connecting means, and at the other end is connected to the support structure (not shown) via a connecting element 58.

[0138] The assembly further includes a control circuit (not shown). During operation, the control circuit directs a control signal to the SMA wire 30. Supplying power to the SMA wire 30 heats the SMA wire 30. When the transition temperature is reached, the SMA wire 30 begins to contract. This has the effect of compressing the spring 56. When the power supply to the SMA wire is removed and thus the SMA wire can extend, the spring 56 expands and drives the movable member 20 to oscillate about the inclined axis (in the case of Figure 4 the x-axis).

[0139] Natural damping in the system will act to reduce the oscillation, so the SMA wire 30 is periodically energized to drive the oscillation of the movable member. The movable member can oscillate at the resonant frequency of the spring 56.

[0140] The actuator assembly 1 further includes a second SMA wire 30 (not shown in Figure 3A and Figure 3B for clarity). The second SMA wire 30 is perpendicular to the first SMA wire 30 (i.e., the second SMA wire 30 is aligned with the x-axis in Figure 3A and Figure 3B ), and is arranged in a similar manner to the SMA wire 30 shown in Figure 3A and Figure 3B (with corresponding springs). The second SMA wire 30 is arranged to cause the movable member 20 to oscillate about a second inclined axis (i.e., the y-axis in Figure 3A and 3B ). In this way, two SMA wire assemblies (such as the SMA wire assemblies shown in Figure 3A and Figure 3B ) are arranged in series; each inclined axis corresponds to one SMA wire. The result of the combination of the oscillations about the two inclined axes is that the end of the movable member opposite to the point 50 follows a circular path (when viewed along the z direction). This movement can facilitate the movement of the movable member between a plurality of predetermined positions (e.g., four positions), at which different images are captured (in the case of super-resolution imaging) or different images are displayed / projected (in the case of a micro-pendulum). Each SMA wire assembly can be configured to cause the movable member to move between two of the four positions.

[0141] Figure 3A and Figure 3B The embodiment shown in Figure 3B employs an inclination of the movable member 20, but the movable member 20 can alternatively (or additionally) move along the x-axis and the y-axis, i.e., translate along the x-axis and the y-axis. In such an embodiment, the movable member does not pivot about a point or an axis, but is displaced along the x-axis and the y-axis by means (i.e., the SMA wire 30 and the spring 56). This causes the entire movable member 20 to follow a circular path (when viewed in the z-direction).

[0142] Referring Figure 4 , another embodiment is described. The SMA actuator assembly includes a movable member 20 and a support structure 10. The movable member 20 is supported on the support structure 10 in a manner that allows the movable member 20 to tilt relative to the support structure about two orthogonal tilt axes (the x-axis and the y-axis in the depicted embodiment). In some embodiments, the SMA actuator assembly 1 includes a support device that allows the movable member 20 to tilt about two orthogonal tilt axes x, y relative to the support structure 10. The movable member 20 can pivot about a point 50, which is, for example, located at the intersection between the two tilt axes. The support device also allows the movable member 20 to translate along an axis H that is perpendicular to the two tilt axes.

[0143] The movable member 20 includes a lens assembly and an image sensor (both not shown). The lens assembly includes one or more lenses and is arranged to focus an image onto the image sensor. In other embodiments, the movable member can include a display for displaying an image, an image projector for projecting an image, a transmitter, or an illumination source (or only a part of any of these components).

[0144] The movable member includes a guide element 60 that engages with a support surface 62 provided on the support structure 10. The guide element can be provided on the outer surface of the movable member and can be a protrusion. The movable member is configured to move relative to the support surface 62. The support surface 62 follows a helical path around the axis H for most of its length (as the path of the support surface behind the movable member shown in Figure 3B is indicated by a dashed line), and also includes a step portion 64. Although the portion 64 is referred to as a step, as shown in Figure 3B , the corners of the step are smooth to facilitate the relative movement between the guide element 60 and the support surface 62. Figure 4 Figure 3B Figure 4 Figure 3B shows that the corners of the step are smooth to facilitate the relative movement between the guide element 60 and the support surface 62.

[0145] The assembly 1 also includes a biasing device 64, in Figure 4In this case, the biasing device 64 is configured to bias the movable member 20 along axis H in a first direction 66 as indicated by the arrow. Accordingly, the biasing device 64 biases the guiding element 60 into contact with the support surface 62. In Figure 4 the illustrated embodiment, the biasing device 64 is a spring, but alternatively may include one or more magnets, one or more SMA wires, or any other actuator. A biasing device that does not require a power source (e.g., a spring) may be preferred to reduce the power consumption of the actuator assembly.

[0146] For any given position of the guiding element 60 relative to the movable member 20, the force of the biasing device 64 (acting in the downward direction in Figure 4 this case) will cause the guiding element 60 to move downward along the helical path of the support surface 62, which causes the movable member 20 to tilt about point 50. This movement will continue until the guiding element 60 reaches the step portion 64 of the support surface 62 (at which point the guiding element 60 drops into the well).

[0147] The assembly 1 also includes an SMA wire 30 that is connected at one end to the movable member 20 by a connecting element (such as a moving crimp, not shown). The other end of the SMA wire 30 is connected to a support structure by another connecting element (not shown). Once the guiding element 60 has reached the step portion 64, power is supplied to the SMA wire, which causes the SMA wire to contract. This causes the movable member 20 to translate along axis H in a second direction 68 that is opposite to the first direction and opposite to the action of the biasing device 64. The SMA wire 30 is angled relative to axis H (i.e., there is an acute angle between the SMA wire 30 and axis H) such that when the SMA wire 30 contracts, the SMA wire pulls the guiding element 60 upward (as a result of the movement of the movable member 20) and over the step portion 64 of the support surface 62. The SMA wire is angled relative to axis H to ensure that the guiding element 60 continues along the support surface 62 in the desired direction about axis H.

[0148] Once the guiding element 60 has moved past the step portion 64, the SMA wire 30 is de-energized, which causes the SMA wire 30 to cool and expand, and the SMA wire thus no longer resists the force of the biasing device 64 on the movable member. Accordingly, the biasing device 64 serves to pull the movable member 20 downward along axis H in direction 66 (downward in Figure 4 this case), and the guiding element 60 thus continues to move downward along the helical path of the support surface 62.

[0149] This has the following effect: when viewed along axis H, the end of the movable part opposite to point 50 follows a circular path. Thus, the SMA actuator assembly causes the movable part (and thus the lens assembly and the image sensor) to move between multiple predetermined positions in a repeating pattern. Thus, as described above, the movement can be used to achieve super-resolution imaging.

[0150] In an embodiment where the movable part includes, for example, a display or an image projector (or a part thereof), the movement provided by Figure 4 the embodiment can be used as described above to effect a micro-swing of the displayed / projected image.

[0151] For some other embodiments described herein, the assembly 1 further includes a control circuit (not shown) for guiding control signals to the SMA wire 30.

[0152] Figure 4 The movable part 20 in the illustrated embodiment is configured to tilt about the pivot point 50. However, the actuator assembly 1 can equally be configured to allow the movable part to translate along the x-axis and the y-axis. In this way, the movable part is displaced along the x-axis and the y-axis instead of tilting about the x-axis and the y-axis. Such an actuator assembly is configured as Figure 4 shown, but the support means allows the movable part to move along the x-axis and the y-axis. The resulting movement will cause the entire movable part 20 to move in a circular path (when viewed along axis H).

[0153] Figure 4 The advantage of the embodiment shown in is that only a single SMA wire is required to move the movable part between multiple positions in a repeating pattern. This is beneficial in embodiments where power consumption is of particular concern (e.g., in a head-mounted device).

[0154] It should be recognized that Figure 4 the connecting members between the various elements in the embodiment of may need to be configured to allow one element to rotate relative to another element. In addition, variants of the embodiment of are envisioned, including: Figure 4 the embodiment of include:

[0155] - A support surface 62 may be provided on the movable part and a guiding element may be provided on the support structure;

[0156] - The SMA wire may be used to pull down the guiding element 60 along a helical path, and when the SMA wire is de-energized, a biasing means may bias the movable part upward (i.e., along direction 68).

[0157] As described above, by tilting the movable member about one or more axes of movement and / or by moving the movable member along one or more axes of movement (e.g., translation), the movable member can move between a plurality of predetermined positions in a repeating pattern. Referring to Figure 5 , embodiments are described in which the movable member translates along one or more axes of movement to move between a plurality of predetermined positions.

[0158] Figure 5 FIG. illustrates an SMA actuator device described in detail in patent application WO2013 / 175197, which is incorporated herein by reference. The following description is also provided. The SMA actuator assembly 1 includes a movable member 15 configured to move relative to a support structure 4. The actuator assembly 1 includes four SMA wires 11, 12, 13, and 14, each of which is connected between the movable member 15 and the support structure 4. Each SMA wire is held in a tensioned state so as to apply a force perpendicular to the axis O between the movable member 15 and the support structure 4. In operation, the SMA wires 11 to 14 cause the movable member 15 to move relative to the support structure 4 in two orthogonal directions (x and y, as Figure 5 marked). Each of the SMA actuator wires 11 to 14 is disposed along one side of the movable member 15. Thus, the SMA wires 11 to 14 are arranged in a ring at different angular positions around the axis O. Thus, the four SMA actuator wires 11 to 14 are composed of a first pair of SMA actuator wires 11 and 13 disposed on opposite sides of the axis O and a second pair of SMA wires 12 and 14 disposed on opposite sides of the axis O. The first pair of SMA wires 11 and 13 can be selectively actuated to cause the movable member 15 to move in a first direction in the x-y plane relative to the support structure 4, and the second pair of SMA wires 12 and 14 can be selectively actuated to cause the movable member 15 to move in a second direction transverse to the first direction in the plane relative to the support structure 4. Movement in a direction other than parallel to the SMA wires 11 to 14 can be driven by a combination of the actuation of these pairs of SMA actuator wires 11 to 14 to provide a combination of movements in the lateral direction. Another way of observing this movement is that simultaneous contraction of any pair of actuator wires among the SMA actuator wires 11 to 14 adjacent to each other in the ring will drive the lens element 2 in the direction (in Figure 5 the diagonal direction as marked by the arrows X and Y) bisecting the two SMA wires among the SMA wires 11 to 14.

[0159] Thus, by actuating the SMA wires 11 to 14 in various combinations, movement of the movable member 15 between different positions in the x-y plane can be achieved. As described above, such movement can be used for super-resolution imaging or micro-pendulum.

[0160] Example of a model with repeated movement for super-resolution

[0161] Figures 6A to 6D An example method of repeated movement for implementing super-resolution imaging is shown.

[0162] The basic concept of super-resolution imaging is to capture multiple images, each with a different amount of offset of the image on the image sensor. The images are then combined, and the additional information provided by the additional images is used to create an image with a higher resolution (and / or potentially higher quality) than the original image.

[0163] This simple model assumes a gap between when the image is collected and when the image can be moved to a new position. However, if a rolling shutter is used, there is typically no gap between frames when the image can move on the image sensor. This means that using this simple method, frames need to be discarded when the image is moved, which reduces the rate at which images can be collected.

[0164] Therefore, when four images are collected per cycle, the image can move continuously relative to the image sensor in a cyclic manner. This allows for super-resolution image collection when using a rolling shutter.

[0165] By moving the image sensor, other optical elements, or both (e.g., in the camera module described herein), the image can typically move continuously on the image sensor (the motion having a constant rate or speed).

[0166] In the first manifestation, the motion is circular, and every fourth exposure the SMA wire (or other actuator) moves the image one full circle on the image sensor once. This is shown in Figures 6A - 6D . The timing of the actuator motion is locked to the exposure such that in the middle of the image, when the image is at the top of the circle, the exposure begins. In this case, each of the four exposures can directly correspond to one of the super-resolution pixels indicated by the grid shown in Figures 6A - 6D . Associating the exposures in this way obtains the best image quality and thus occurs in the center of the image.

[0167] At the top and bottom of the image, four independent light samples are still taken, but these light samples are not arranged in a uniform square grid. This data is converted into a square grid to provide a super-resolution image.

[0168] The same method can be applied to create super-resolution images from images displayed on a display panel or projected by a projector, thus achieving jitter.

[0169] Last paragraph

[0170] In any of the embodiments described herein, the movable component may include one or more of the following: a light-emitting element (such as a laser or a laser array), a dimming element (such as a diffraction grating or a reflective element), a lens assembly, an image sensor, a display, or an image projector (or a part of any of these components).

[0171] Although the SMA actuator assembly has been described in connection with a control circuit configured to apply a drive signal to one or more SMA wires so as to cause the movable component to tilt between a plurality of predetermined positions relative to the support structure about one or more axes of movement and / or the movable component to move between a plurality of predetermined positions relative to the support structure along one or more axes of movement in a repeating pattern, this is not strictly required. The present invention extends to providing other features of the SMA actuator assembly described herein, such as Figures 1A - 1B the SMA wire arrangement or the support arrangement described herein.

[0172] The above-described SMA actuator assembly includes SMA wires. The term "shape memory alloy (SMA) wire" may refer to any element comprising SMA. The SMA wire may have any shape suitable for the purposes described herein. The SMA wire may be elongate 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 wire. It is also possible that the length of the SMA wire (however defined) may be similar to one or more of the other dimensions of the SMA wire. The SMA wire may be bendable, or in other words, flexible. In some examples, when connected in a straight line between two elements, the SMA wire can only apply a tensile force that pushes the two elements together. In other examples, the SMA wire may bend around an element, and when the SMA wire tends to straighten in a tensioned state, the SMA wire can apply a force to the element. The SMA wire may be beam-like or rigid and capable of applying different (e.g., non-tensile) forces to an element. The SMA wire may or may not include non-SMA material(s) and / or component(s). For example, the SMA wire may include a core of SMA and a coating of non-SMA material. Unless the context otherwise requires, the term "SMA wire" may refer to any configuration of SMA wires that act as a single actuating element, e.g., the single actuating element may be individually controlled to produce a force acting on an element. For example, the SMA wire may include two or more portions of SMA wires arranged mechanically in parallel and / or in series. In some arrangements, the SMA wire may be part of a larger segment of SMA wire. Such a larger segment of SMA wire may include two or more portions that can be individually controlled, thereby forming two or more SMA wires.

Claims

1. An SMA actuator assembly, characterized in that, It includes: A support structure; A camera module, which is supported on the support structure in a manner that allows the camera module to tilt relative to the support structure about two orthogonal tilt axes, wherein the camera module includes an image sensor and a lens assembly arranged to focus an image onto the image sensor; Two or more SMA wires, which are arranged to tilt the camera module relative to the support structure about the two orthogonal tilt axes; A control circuit, which is configured to apply drive signals to the two or more SMA wires so as to drive the camera module to tilt between predetermined positions in a repeating pattern relative to the support structure.

2. The SMA actuator assembly according to claim 1, wherein, The control circuit is configured to apply drive signals to the two or more SMA wires for achieving super-resolution imaging of the camera module.

3. The SMA actuator assembly according to claim 1, wherein, The predetermined positions in the repeating pattern are arranged in two degrees of freedom.

4. The SMA actuator assembly according to any one of claims 1-3, characterized in that The control circuit is configured to apply drive signals to the two or more SMA wires so as to drive the camera module to tilt between the predetermined positions at a predetermined frequency.

5. The SMA actuator assembly according to claim 4, characterized in that, The resonance frequency at which the camera module tilts about the two orthogonal tilt axes is substantially equal to the predetermined frequency.

6. The SMA actuator assembly according to any one of claims 1-3 and 5, characterized in that, The SMA actuator assembly includes a first elastic element, wherein the two or more SMA wires include a first SMA wire, the first SMA wire being configured to deform the first elastic element when contracting, and wherein the first elastic element is configured to oscillate at a first frequency so as to cause the camera module to tilt or move between at least some of the predetermined positions.

7. The SMA actuator assembly according to claim 6, wherein The SMA actuator assembly includes a second elastic element, wherein the two or more SMA wires include a second SMA wire, the second SMA wire being configured to deform the second elastic element when contracting, and wherein the second elastic element is configured to oscillate at a second frequency so as to cause the camera module to tilt or move between at least some of the predetermined positions.

8. The SMA actuator assembly according to any one of claims 1-3, 5, and 7, characterized in that, The two or more SMA wires include four SMA wires.

9. The SMA actuator assembly according to claim 8, wherein, The two or more SMA wires include a total of four SMA wires, the four SMA wires being arranged to be able to apply a torque to the camera module about an axis perpendicular to the two orthogonal tilt axes.

10. The SMA actuator assembly according to claim 9, wherein, Two of the four SMA wires are arranged to apply a torque to the camera module in a first direction, and the other two SMA wires are arranged to apply a torque to the camera module in an opposite second direction.

11. The SMA actuator assembly according to claim 9 or 10, characterized in that, The four SMA wires are arranged in a ring at different angular positions about the axis, and the sequentially arranged SMA wires are arranged to apply forces to the camera module in alternating directions.

12. The SMA actuator assembly according to claim 9 or 10, characterized in that, The four SMA wires are arranged such that corresponding subsets composed of two SMA wires are arranged to apply forces to the camera module in four corresponding directions along the two orthogonal tilt axes.

13. The SMA actuator assembly according to claim 9 or 10, characterized in that, The four SMA wires include two pairs of SMA wires, and when observed perpendicular to the two orthogonal tilt axes, each pair of SMA wires is arranged on opposite sides of the camera module.

14. The SMA actuator assembly according to claim 13, wherein When viewed perpendicular to the two orthogonal tilt axes, the SMA wires in each pair cross or overlap.

15. The SMA actuator assembly according to any one of claims 9-10 and 14, characterized in that, The four SMA wires are arranged to apply forces to the camera module in angular directions that are offset from each other by 90 degrees.

16. The SMA actuator assembly according to any one of claims 1-3, 5, 7, 9-10, and 14, characterized in that, The two or more SMA wires are arranged parallel to the two orthogonal tilt axes.

17. The SMA actuator assembly according to any one of claims 1-3, 5, 7, 9-10 and 14, characterized in that, The two or more SMA wires are arranged at an angle relative to the two orthogonal tilt axes.

18. The SMA actuator assembly according to any one of claims 1-3, 5, 7, 9-10 and 14, characterized in that, The SMA actuator assembly further includes a support device that allows the camera module to tilt relative to the support structure about the two orthogonal tilt axes.

19. The SMA actuator assembly according to claim 18, wherein The support device is arranged to constrain translational movement of the camera module along the two orthogonal tilt axes.

20. The SMA actuator assembly according to claim 19, wherein, The support device is further arranged to constrain translational movement of the camera module along an axis perpendicular to the two orthogonal tilt axes and / or rotational movement of the camera module about an axis perpendicular to the two orthogonal tilt axes.

21. The SMA actuator assembly according to claim 18, wherein The support device is arranged to constrain movement of the camera module along the two orthogonal tilt axes at positions offset along an axis perpendicular to the two orthogonal tilt axes due to the forces applied to the camera module by the two or more SMA wires.

22. The SMA actuator assembly according to claim 18, wherein, The support device includes a sheet or flexure connected between the support structure and the camera module.

23. The SMA actuator assembly according to claim 18, wherein The support device includes a pivot or sliding support.

24. The SMA actuator assembly according to claim 18, wherein, The support device includes a flexible block material.

25. An SMA actuator assembly, characterized in that, It includes: A support structure; A movable component that is supported on the support structure in a manner that allows the movable component to tilt relative to the support structure about one or more movement axes and / or the movable component to move along one or more movement axes; One or more SMA wires that are arranged to tilt the movable component relative to the support structure about the one or more movement axes and / or to move the movable component along the one or more movement axes; And A control circuit that is configured to apply drive signals to the one or more SMA wires so as to cause the movable component to tilt relative to the support structure about the one or more movement axes between predetermined positions in a repeating pattern and / or the movable component to move relative to the support structure along the one or more movement axes between predetermined positions in a repeating pattern.

26. The SMA actuator assembly according to claim 25, wherein The movable component includes a camera module, where the camera module includes a lens assembly defining an optical axis and an image sensor, where the lens assembly is arranged to focus an image onto the image sensor, and where the one or more movement axes are perpendicular to the optical axis.

27. The SMA actuator assembly according to claim 26, wherein The control circuit is configured to apply drive signals to the one or more SMA wires for implementing super-resolution imaging using the camera module.

28. The SMA actuator assembly according to claim 25, wherein, The SMA actuator assembly includes a projector for projecting an image, where the movable component includes at least a portion of the projector such that tilting or movement of the movable component relative to the support structure moves the projected image.

29. The SMA actuator assembly according to claim 25, wherein, The control circuit is configured to apply a drive signal to the one or more SMA wires for effecting a micro - swing of the projected image.

30. The SMA actuator assembly according to any one of claims 25 - 29, characterized in that, The predetermined positions in the repeating pattern are arranged in two degrees of freedom.

31. The SMA actuator assembly according to any one of claims 25 - 29, characterized in that, The control circuit is configured to apply a drive signal to the one or more SMA wires so as to cause the movable member to tilt relative to the support structure about two orthogonal tilt axes in the repeating pattern between the predetermined positions, and wherein the one or more SMA wires include a total of four SMA wires arranged to apply a torque to the movable member about an axis perpendicular to the two orthogonal tilt axes.

32. The SMA actuator assembly according to any one of claims 25-29, characterized in that, The control circuit is configured to apply a drive signal to the one or more SMA wires so as to cause the movable member to tilt or move between the predetermined positions at a predetermined frequency.

33. The SMA actuator assembly according to claim 32, wherein, The resonance frequency at which the movable member is caused to tilt about the one or more movement axes or the movable member is caused to move along the one or more movement axes is substantially equal to the predetermined frequency.

34. The SMA actuator assembly according to claim 32, wherein, The SMA actuator assembly further includes a first elastic element, wherein the one or more SMA wires include a first SMA wire configured to deform the first elastic element upon contraction, and wherein the first elastic element is configured to oscillate at a first frequency so as to cause the movable member to tilt or move between at least some of the predetermined positions.

35. The SMA actuator assembly according to claim 34, wherein, The SMA actuator assembly further includes a second elastic element, wherein the one or more SMA wires include a second SMA wire configured to deform the second elastic element upon contraction, and wherein the second elastic element is configured to oscillate at a second frequency so as to cause the movable member to tilt or move between at least some of the predetermined positions.

36. The SMA actuator assembly according to any one of claims 25-29 and 33-35, characterized in that, The SMA actuator assembly further includes a support device that allows the movable member to tilt relative to the support structure about the one or more movement axes and / or the movable member to move relative to the support structure along the one or more movement axes.

37. The SMA actuator assembly according to claim 36, wherein, The support device is configured to allow the movable member to tilt relative to the support structure about two orthogonal tilt axes, wherein the support device is arranged to constrain translational movement of the movable member along the two orthogonal tilt axes.

38. The SMA actuator assembly according to any one of claims 25-29, 33-35 and 37, characterized in that, The SMA actuator assembly is configured to tilt or move the movable member such that at least a portion of the movable member moves in a circular motion when viewed along a main axis perpendicular to the one or more movement axes.

39. The SMA actuator assembly according to claim 36, wherein, The support device is configured to guide at least a portion of the movable member to move in a circular motion when viewed along a main axis perpendicular to the one or more movement axes.

40. The SMA actuator assembly according to claim 39, wherein, The one or more SMA wires are configured to drive at least a portion of the movable member to move along the main axis in a first direction upon contraction, and wherein the SMA actuator assembly includes a biasing means configured to cause at least a portion of the movable member to move along the main axis in a second direction opposite to the first direction, and wherein the support means converts the movement of at least a portion of the movable member along the main axis into movement along the loop.

41. The SMA actuator assembly according to claim 39 or claim 40, characterized in that, The support means is configured to guide at least a portion of the movable member along a helical path about the main axis.

42. The SMA actuator assembly according to any one of claims 25-29, 33-35, 37 and 39-40, characterized in that, The one or more SMA wires include a total of one SMA wire that causes the movable member to tilt or move between the predetermined positions.

Images