Actuator assembly and camera module

Abstract

An actuator assembly and a camera module are described. The actuator assembly includes a first portion, a second portion, and a first support device mechanically coupling the first portion to the second portion. The actuator assembly also includes a first drive device including four segments of shape memory alloy wires. The first support means and the first drive means are configured such that the second portion is rotatable relative to the first portion about an axis parallel to the first direction. The actuator assembly also includes a third portion and a second support device mechanically coupling the second portion to the third portion. The actuator assembly further comprises a second driving device, and the second driving device comprises four sections of shape memory alloy wires. The second support means, the first drive means and the second drive means are configured such that the third portion moves toward or away from the first portion in the first direction in response to a torque applied by the first drive means and / or the second drive means about an axis parallel to the first direction.

Description

Technical Field

[0001] The present application relates to an actuator assembly, and in particular to an actuator assembly comprising a plurality of sections of shape memory alloy (SMA) wires. Background Art

[0002] Such an actuator assembly may be used, for example, in a camera module (also simply referred to as a camera) to move a lens assembly in a direction perpendicular to an optical axis, thereby providing optical image stabilization (OIS). Where such a camera module is a compact camera module to be incorporated into a portable electronic device such as a mobile phone, miniaturization may be important.

[0003] WO 2013 / 175197 A1 describes an SMA actuation device that uses a total of four SMA actuator wires to move a movable element relative to a support structure in two orthogonal directions, each SMA actuator wire being connected at its two ends between the movable element and the support structure and extending perpendicularly to the main axis line. None of the SMA actuator wires are co-linear, but the SMA actuator wires have such an arrangement that the SMA actuator wires can be selectively driven to move the movable element relative to the support structure to any position within the range of movement without applying any net torque to the movable element in a plane about the two orthogonal directions of the main axis line.

[0004] WO 2019 / 243849 A1 describes a shape memory alloy actuator device, which includes a support structure and a movable element. A spiral support device that supports the movable element on the support structure guides the spiral movement of the movable element relative to the support structure around the spiral axis. At least one shape memory alloy actuator line is connected between the support structure and the movable element in a plane orthogonal to the spiral axis or at an acute angle to the plane so as to drive the movable element to rotate around the spiral axis, and the spiral support device converts the rotation into the spiral movement.

[0005] WO 2019 / 086855 A1 describes a camera with an actuator assembly, which includes a supporting platform, a moving platform supporting a lens assembly, an SMA wire connected to the supporting platform and the moving platform, a support member supporting the moving platform on the supporting platform, and two arms extending between the supporting platform and the moving platform. Utility Model Content

[0006] According to a first aspect of the utility model, an actuator assembly is provided, which includes a first part, a second part and a first supporting device that mechanically couples the first part to the second part. The actuator assembly also includes a first drive device, which includes four sections of shape memory alloy wire. The first supporting device and the first driving device are configured so that the second part can rotate relative to the first part around an axis parallel to the first direction. The actuator assembly also includes a third part and a second supporting device that mechanically couples the second part to the third part. The actuator assembly also includes a second driving device, which includes four sections of shape memory alloy wire. The second supporting device, the first driving device and the second driving device are configured so that in response to a torque applied by the first driving device and / or the second driving device around an axis parallel to the first direction, the third part moves toward or away from the first part along the first direction.

[0007] Thus, both the first drive means and the second drive means may act on the second support means and be actuated in coordination. This may be used to increase the movement (ie the stroke) in the first direction.

[0008] The first part may include or take the form of a static part. The static part may be a chassis section. The second part may include or take the form of an intermediate moving part. The intermediate part may be an autofocus chassis section. The third part may include or take the form of a moving part. The moving part may be a lens holder that supports one or more lenses for the camera.

[0009] Each of the plurality of lengths of SMA wire in the first actuator may be non-collinear with other lengths of SMA wire in the first actuator. Each of the plurality of lengths of SMA wire in the second actuator may be non-collinear with other lengths of SMA wire in the second actuator.

[0010] The multiple lengths of SMA wire in the first actuator can be arranged to apply a torque between the first portion and the second portion about an axis parallel to the first direction and / or apply a force in a direction substantially perpendicular to the first direction. The multiple lengths of SMA wire in the second actuator can be arranged to apply a torque between the first portion and the third portion about an axis parallel to the first direction and / or apply a force in a direction substantially perpendicular to the first direction.

[0011] Each shape memory alloy wire of the first actuator can be connected between the first portion and the second portion directly or via one or more intermediate structures. Each shape memory alloy wire of the second actuator can be connected between the first portion and the third portion directly or via one or more intermediate structures.

[0012] The first support device and the first drive device may be configured to enable the second part to move perpendicularly to the first direction relative to the first part. The second support device and the second drive device may be configured to enable the third part to move perpendicularly to the first direction relative to the first part.

[0013] The actuator assembly may be configured to enable the second portion and the third portion to move relative to the first portion perpendicular to the first direction while maintaining a position of the third portion relative to the second portion.

[0014] The actuator assembly may be configured to enable the second portion and the third portion to move differently perpendicular to the first direction so as to tilt the third portion relative to the first portion and the second portion about an axis perpendicular to the first direction.

[0015] The first support device may be configured to resist movement of the second part toward or away from the first part along the first direction. Being configured to resist may mean hindering, or even preventing. The first support device may include one or more flexures connected between the first part and the second part. The flexure may be configured to resist movement of the second part toward and / or away from the first part along the first direction.

[0016] The first support means may be configured to allow the second part to move relative to the first part in a plane perpendicular to the first direction.

[0017] The first support device may include a planar support or take the form of a planar support. The planar support may include a first plate and a second plate facing each other, and at least three protrusions (or "protrusions"). Each protrusion may extend away from one of the first plate and the second plate toward the other of the first plate and the second plate, respectively, and be in slidable contact with the other of the first plate and the second plate.

[0018] At least three protrusions can extend away from the same plate (e.g., the first plate). However, in some embodiments, one or more but not all protrusions can extend from one plate (e.g., the first plate), and the remaining protrusions can extend from another plate (e.g., the second plate).

[0019] The planar support may include a first plate and a second plate facing each other, and at least three ball supports interposed between the first plate and the second plate.

[0020] The first plate and the second plate may include a first hole and a second hole, respectively. The first hole and the second hole may preferably be circular. The first hole and the second hole may preferably be coaxial. The first hole and the second hole may preferably be coaxial in a static or neutral configuration of the actuator assembly, and may cease to be coaxial when the actuator assembly is actuated away from the static or neutral configuration.

[0021] The four lengths of shape memory alloy wire in the first drive device may be substantially coplanar.

[0022] The second portion may include a central portion and a resilient arm extending from the central portion and connected to the first portion to provide a force for biasing the second portion toward the first portion and / or for biasing the second portion toward a central position through which an axis parallel to the first direction passes.

[0023] The four lengths of shape memory alloy wire in the second drive device may be substantially coplanar.

[0024] The four segments of shape memory alloy wire can each extend at an angle to a plane perpendicular to the first direction. The angle can be very small. The angle can be less than 20 degrees, less than 10 degrees in some cases, and less than 5 degrees in other cases. The angle can change at least as the position of the third portion along the first direction changes. When the third portion is located at a center position along the first direction, the angle can be zero.

[0025] The four lengths of shape memory alloy wire in the first drive device may be substantially coplanar in a first plane. The four lengths of shape memory alloy wire in the second drive device may be substantially coplanar in a second plane. The first plane and the second plane may be parallel.

[0026] The first plane and the second plane may be offset from each other along the first direction.The first plane and the second plane may be substantially coplanar.

[0027] The first plane and the second plane may be substantially coplanar if the distance separating the first plane and the second plane along the first direction is less than or equal to 10 times the thickness of a segment of the shape memory alloy wire. The first plane and the second plane may be substantially coplanar if the respective SMA wires of the first actuator and the second actuator all span a length parallel to the first direction of less than or equal to 500 microns, less than or equal to 750 microns, or less than or equal to 1 mm.

[0028] The four segments of shape memory alloy wire in the first drive device may span a first length parallel to the first direction. The four segments of shape memory alloy wire in the second drive device may span a second length parallel to the first direction. The first length and the second length may at least partially overlap.

[0029] The four sections of shape memory alloy in the first drive device and the four sections of shape memory alloy in the second drive device may each be connected to the first portion via a connecting portion. The connecting portion may be located in a plane perpendicular to the first direction.

[0030] The actuator assembly may include four shape memory alloy wires, each of which provides one section of four sections of shape memory alloy in the first drive device and one section of four sections of shape memory alloy in the second drive device. Each shape memory alloy wire may be connected to the first portion via a common connection at (or near) the midpoint of the shape memory alloy wire. The common connection may be connected to a system ground or a common mode voltage and may be used as a common current return. In this way, the drive current applied to either side of the common connection may vary independently. The common connection may take the form of a crimping portion.

[0031] The second support means may comprise or take the form of a helical support. The helical support may be configured to convert a relative rotation between the second part and the third part about an axis parallel to the first direction (caused by the first and / or second drive means) into a relative movement of the second part and the third part parallel to the first direction. The helical support may comprise or take the form of a thread.

[0032] The second bearing device may include a spiral rolling element bearing or take the form of a spiral rolling element bearing. The spiral rolling element bearing may include a plurality of spiral bearing portions arranged in a ring around an axis parallel to the first direction. Each spiral bearing portion may include a first bearing surface, a second bearing surface and at least one rolling element, the at least one rolling element being arranged to be guided along a spiral path by the first bearing surface and the second bearing surface. Each spiral bearing portion may include a flexible ramp. The flexible ramp may be preloaded in a balanced or neutral configuration of the first bearing.

[0033] The helical bearing may comprise or take the form of a sliding surface configured to cooperate with and be guided by the bearing surface.

[0034] The second support device may include a spiral flexure or take the form of a spiral flexure. The spiral flexure may include or take the form of at least three flexure arms, which extend in a direction parallel to the first direction and in the same sense around an axis parallel to the first direction. The spiral flexure may include four, five or more flexure arms or be composed of four, five or more flexure arms. The spiral flexure may include a ring. At least three flexures (e.g., five or more flexures) may extend from the ring. The flexure arms may be positioned at equally spaced angles around the center of mass of the ring. The center of mass of the ring may coincide with an axis parallel to the first direction. In a static or neutral configuration of the actuator assembly, the center of mass of the ring may coincide with an axis parallel to the first direction, and when the actuator assembly is actuated away from a static or neutral configuration, the center of mass of the ring may stop coinciding. The ring and the flexure arms may be formed as a single piece.

[0035] The actuator may further include an annular ring connected to the third portion and interposed between the third portion and the second portion.

[0036] The second portion may include a first annular member. The first annular member may be substantially coplanar with the third portion at a position closest to the third portion relative to the second portion along the first direction. This may help reduce the height of the actuator assembly parallel to the first direction.

[0037] The third portion may include a second annular member or take the form of a second annular member. The first annular member and the second annular member may be substantially coaxial at a central lateral position of the third portion relative to the second portion. The second annular member may be located inside the first annular member. The second annular member may be located inside the first annular member. The second portion may include a first pair of arms extending radially away from the first annular member. The third portion may include a second pair of arms extending radially away from an axis parallel to the first direction. When the third portion takes the form of a second annular member, the second pair of arms may extend radially away from the second annular member.

[0038] The camera module may include an actuator assembly, an image sensor supported by one of the first portion and the third portion, and a lens supported by the other of the first portion and the third portion.

[0039] The camera module may further include a controller configured to control the actuator assembly to implement an auto-focus function using movement of the third portion along the first direction toward or away from the second portion.

[0040] The spiral rolling element support comprises: a first piece, the first piece having a plurality of first guide sections in the first piece; a second piece, the second piece having a plurality of second guide sections, each second guide section facing the first guide section; and a plurality of ball bearing elements, wherein each ball bearing element is located between the first piece and the second piece in the first guide section and the second guide section; wherein the guide sections are tapered so that the relative rotation of the first piece and the second piece in a first direction causes each ball bearing element to roll toward the narrower end of each guide section, thereby moving the first piece and the second piece away from each other, and the relative rotation of the first piece and the second piece in an opposite second direction causes each ball bearing element to roll toward the wider end of each guide section, thereby moving the first piece and the second piece toward each other.

[0041] The first piece and the second piece are sheets of material, and the first guide section and the second guide section are holes in the sheets of material.

[0042] According to a second aspect of the present invention, a method is provided, which includes enabling the actuator assembly of the first aspect or a camera module including the actuator assembly of the first aspect to implement an automatic focusing function and / or an optical image stabilization function of a camera.

[0043] The method may include actuating the first drive means and / or the second drive means to apply a torque to the second support means about an axis parallel to the first direction. In response to the torque, the third portion moves along the first direction towards or away from the first portion.

[0044] The method may include actuating the first drive device to rotate the second portion in a first orientation about an axis parallel to the first direction while rotating the third portion in an opposite second orientation about the axis. In this manner, a maximum displacement of the third portion relative to the first portion parallel to the first direction may be approximately twice the maximum displacement obtainable if the first drive device and the second portion are omitted and the second support couples the first portion and the third portion.

[0045] The method may include actuating the first drive means and the second drive means to displace the second portion and the third portion relative to the first portion a distance perpendicular to the first direction while maintaining the position of the third portion relative to the second portion.

[0046] The method may include actuating a first drive device and a second drive device to displace the second portion relative to the first portion in a second direction by a first distance, and to displace the third portion relative to the first portion in a third direction by a second distance. Both the second direction and the third direction may be perpendicular to the first direction, so as to tilt the third portion relative to the first portion and the second portion about an axis perpendicular to the first direction.

[0047] If the second direction and the third direction are different, the first distance may be equal to the second distance. If the first distance and the second distance are different, the second direction and the third direction may be the same.

[0048] The method may include displacing the second and third portions together by the same amount ("shifting"), followed by (or before) displacing the second and third portions by different amounts and / or in different directions ("tilting"). The method may include using a combination of shifting and tilting to displace the second and third portions.

[0049] According to a third aspect of the present invention, a computer program stored on a non-transitory machine-readable medium is provided. When executed by a processor of a device including the actuator assembly of the first aspect or a camera module including the actuator assembly of the first aspect, the computer program causes the actuator assembly or the camera module to perform the method of the second aspect.

[0050] According to a fourth aspect of the utility model, an actuator assembly is provided, comprising a first part, a second part and a support device that mechanically couples the first part to the second part. The actuator also includes a first drive device, which includes one or more segments of shape memory alloy wire. The first support device and the first drive device are configured so that the second part can rotate relative to the first part around an axis parallel to the first direction. The actuator assembly also includes a third part and a second support device that mechanically couples the second part to the third part. The actuator assembly also includes a second drive device, which includes one or more segments of shape memory alloy wire. The second support device, the first drive device and the second drive device are configured so that in response to a torque applied by the first drive device and / or the second drive device around an axis parallel to the first direction, the third part moves toward or away from the first part along the first direction.

[0051] The actuator assembly of the fourth aspect may comprise features corresponding to any features of the actuator of the first aspect.The definitions applicable to the actuator of the first aspect may equally apply to the actuator of the fourth aspect.

[0052] The first drive device may include a first section of shape memory alloy wire and a second section of shape memory alloy wire, the first section of shape memory alloy wire being configured to apply a torque clockwise around an axis parallel to the first direction, and the second section of shape memory alloy wire being configured to apply a torque counterclockwise around an axis parallel to the first direction. The first drive device may include only the first section and the second section of shape memory alloy wire, without including another section of shape memory alloy wire.

[0053] The second drive device may include a third section of shape memory alloy wire and a fourth section of shape memory alloy wire, the third section of shape memory alloy wire being configured to apply torque clockwise around an axis parallel to the first direction, and the fourth section of shape memory alloy wire being configured to apply torque counterclockwise around an axis parallel to the first direction. The second drive device may include only the third section and the fourth section of shape memory alloy wire, without including other sections of shape memory alloy wire.

[0054] The actuator assembly may also include one or more first springs coupling the first portion to the second portion. Each first spring may be configured to resist the contraction of at least one section of the shape memory alloy wire of the first drive device. Each first spring may be directly connected to the first portion and / or the second portion, or may be connected to the first portion and / or the second portion via one or more intermediate components.

[0055] The actuator assembly may also include one or more second springs coupling the second portion to the third portion. Each second spring may be configured to resist the contraction of at least one section of the shape memory alloy wire of the second drive device. Each second spring may be directly connected to the second portion and / or the third portion, or may be connected to the second portion and / or the third portion via one or more intermediate components.

[0056] In this document, the term annulus may encompass any ring or loop shape, including circular, oval, square, rectangular or any other regular or irregular shape.The annulus may have an outer perimeter with a first shape and an inner perimeter with a second, different shape.

[0057] Herein, any or all of the axes parallel to the first direction may correspond to the same axis defined relative to any of the first, second, and third portions and may move with the corresponding portion when the SMA wire is actuated. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Certain embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings, in which:

[0059] Figure 1 is a schematic diagram of a camera including a shape memory alloy (SMA) actuator assembly;

[0060] Figure 2 schematically illustrates possible degrees of freedom that may be provided by an SMA actuator assembly;

[0061] Figure 3 is a schematic plan view of a drive device that may be used in an SMA actuator assembly;

[0062] Figure 4 Is adopted Figure 3 A schematic perspective view of a flat SMA actuator assembly of the drive device shown;

[0063] Figure 5A is a schematic side view of a planar (three-point) support;

[0064] Figure 5B yes Figure 5A A schematic exploded projection of the planar support shown;

[0065] Figure 6 is a schematic perspective view of a helical flexure bearing;

[0066] Fig. 7A is a schematic exploded projection of a spiral sliding bearing;

[0067] Figure 7B yes Fig. 7AA schematic projection of a spiral sliding bearing is shown;

[0068] Fig. 8A is a plan view of the rotating support;

[0069] Figure 8B is along Fig. 8A A cross section of the line marked A-A' in;

[0070] Figure 8C is an exploded perspective view of an alternative spiral support;

[0071] Figure 8D-8F yes Figure 8C Perspective views of an alternative helical support in three different configurations;

[0072] Fig. 9 is a schematic exploded projection of a first actuator assembly;

[0073] Fig.10 yes Fig. 9 a schematic projection of a first actuator assembly shown;

[0074] Fig.11 yes Fig. 9 A schematic block diagram of a first actuator assembly is shown;

[0075] Fig.12 is a schematic plan view of a second actuator assembly;

[0076] Fig.13A It is along Fig.12 a cross section of the second actuator assembly along the line marked BB' in FIG.

[0077] Fig. 13B It is along Fig.12 a cross section of the second actuator assembly along the line marked CC' in FIG.

[0078] Fig.14 is a schematic exploded projection of a third actuator assembly;

[0079] Fig.15 yes Fig.14 a schematic projection of a third actuator assembly shown;

[0080] Fig.16 is a schematic plan view of a first dual SMA wire actuator; and

[0081] Fig.17 is a schematic plan view of a second dual SMA wire actuator. DETAILED DESCRIPTION

[0082] camera

[0083] Reference Figure 1 , shows a camera 1 incorporating an SMA actuator assembly 2 (also referred to herein as an "SMA actuator" or simply an "actuator").

[0084] The camera 1 comprises a first part 3 and a second part 4 .

[0085] The first part 3 of the camera takes the form of a support structure and comprises a base 5. The second part 4 of the camera takes the form of a lens assembly suspended on the first part 3 of the camera 1 by an SMA actuator assembly 2.

[0086] The image sensor 6 is disposed in front of the front side of the base 5 , that is, the image sensor 6 is interposed between the lens assembly 4 and the base 5 .

[0087] The SMA actuator assembly 2 supports the lens assembly 4 and the image sensor 6 in a manner that allows one or more degrees of freedom of the lens assembly 4 relative to the support structure 3. The lens assembly 4 has an optical axis O.

[0088] The camera 1 includes an integrated circuit (IC) 7 implementing a control circuit, and also includes a gyro sensor (not shown). The support structure 3 also includes a can 8 (or shielding cover) protruding forward from the base 5 to enclose and protect other components of the camera 1.

[0089] The lens assembly 4 comprises a lens holder 9 in the form of a cylindrical body, which supports two lenses 10 arranged along an optical axis O. Generally, any number of lenses 10 may be included, such as only one lens 10 or three or more lenses 10. Preferably, each lens 10 has a diameter of up to about 20 mm. Therefore, the camera 1 may be referred to as a miniature camera.

[0090] The lens assembly 4 is arranged to focus the image onto an image sensor 6. The image sensor 6 captures the image and may be of any suitable type, such as a charge-coupled device (CCD) or a complementary metal-oxide-semiconductor (CMOS) device.

[0091] The lenses 10 are supported on a lens holder 9, and the lens holder 9 is supported by the SMA actuator assembly 2 so that the lens assembly 4 can move along the optical axis O relative to the support structure 3, for example to provide focus or zoom. Although all of the lenses 10 are fixed to the lens holder 9 in this example, in general, one or more of the lenses 10 can be mounted to a component other than the lens holder 9 and can be fixed in an appropriate position relative to the image sensor 6, so that at least one of the lenses 10 is attached to the lens holder and is movable along the optical axis O relative to the image sensor 6.

[0092] Typically, in use, the lens assembly 4 is movable relative to the image sensor 6 orthogonal to the optical axis O, the effect of which is that the image on the image sensor 6 is moved. For example, if a set of right-handed orthogonal axes x, y, z are arranged so that the third axis z is oriented substantially parallel to the optical axis O, the lens assembly 4 may be movable in a direction parallel to the first axis x and / or in a direction parallel to the second axis y. This is used to provide optical image stabilization (OIS), compensating for movement of the camera 1 that may be caused by hand shake or the like. The movement to provide OIS does not need to be constrained to the xy plane. Additionally or alternatively, the OIS function may be provided by tilting the lens assembly 4 or both the lens assembly 4 and the image sensor 6 around an axis parallel to the first x axis and / or around an axis parallel to the second y axis. Furthermore, the lens assembly 4 or at least one of its lenses 10 may be movable parallel to the optical axis O (parallel to the third axis z) to provide focusing of the image formed on the image sensor 6, for example as part of an autofocus (AF) function.

[0093] The present description mainly relates to examples of an SMA actuator assembly 2 that provides a combination of autofocus (AF) and optical image stabilization (OIS) based on moving a lens assembly 4 relative to a support structure 3 .

[0094] Degrees of Freedom

[0095] Also refer to Figure 2 , showing the possible types of movement (or degrees of freedom) that can be provided by the SMA actuator assembly 2.

[0096] The first degree of freedom (DOF) Tx corresponds to movement parallel to the first axis x. The second DOF Ty corresponds to movement parallel to the second axis y. The third DOF Tz corresponds to movement parallel to the third axis z, which is oriented substantially parallel to the optical axis O. The third DOF Tz corresponds to movement of the lens assembly 3 toward or away from the image sensor 6. The first axis x, the second axis y, and the third axis z form a right-handed Cartesian coordinate system. The fourth DOF Rx corresponds to rotation around an axis parallel to the first axis x. The fifth DOF Ry corresponds to rotation around an axis parallel to the second axis y. The sixth DOF Rz corresponds to rotation around an axis parallel to the third axis z. In some examples, one or more of the axes can be attached to the SMA actuator assembly 2 or the first part, the second part, or any other element of the camera 1 (and move and / or rotate / tilt with it). For example, the origin can be an element of the camera 1, such as the image sensor 6 or the lens 10 of the lens assembly 4.

[0097] The motion of the lens assembly 4 relative to the support structure 3 can be decomposed into any or all of the components of the first to sixth DOF (movement) Tx, Ty, Tz, Rx, Ry, Rz. Although described as degrees of freedom, in some cases, translation and rotation can be associated. For example, a given translation Tz along the third axis z can be associated with a corresponding rotation Rz so that the motion of the lens assembly 4 is spiral. A pair of square brackets can be used to refer to such an associated motion to avoid confusion with more independent motions, for example [Tz, Rz] will represent the spiral motion described below. The spiral motion [Tz, Rz] can be provided by a spiral support, such as a spiral roller support or a spiral flexure.

[0098] The present description is primarily directed to an SMA actuator assembly 2 that provides motion corresponding to a first DOF Tx and a second DOF Ty to provide OIS functionality herein, while motion parallel to a third axis z [Tz, Rz] provides AF functionality. Other specific motions are constrained by the SMA actuator assembly 2 described herein. Some examples of the SMA actuator assembly 2 according to the present description may additionally or alternatively tilt the lens 10 to provide OIS functionality corresponding to a fifth DOF Rx and a sixth DOF Ry.

[0099] Shape memory alloy drive components

[0100] Also refer to Figure 3 , schematically illustrates a driving device 11 included in the SMA actuator assembly 2.

[0101] The first drive device 11 includes a first structure 12 and a second structure 13. The second structure 13 may be supported within the boundaries defined by the first structure 12 (eg, Figure 3 ). The second structure 12 generally need not provide a complete or uninterrupted border. The first structure 12 and the second structure 13 may take the form of corresponding patterned metal sheets (eg, etched or machined stainless steel), and they may be coated with an electrically insulating dielectric material.

[0102] Four SMA wires 141, 142, 143, 144 (shown in dot-dash lines to aid visibility) form a loop around the second structure 13. The first SMA wire 141 and the third SMA wire 143 extend substantially parallel to the second axis y and are spaced apart in a direction parallel to the first axis x. Contraction of the first SMA wire 141 will apply a force to the second structure 13 in a negative direction -y, while contraction of the third SMA wire 143 will apply a force to the second structure 13 in a positive direction +y. The second SMA wire 142 and the fourth SMA wire 144 extend substantially parallel to the first axis x and are spaced apart in a direction parallel to the second axis y. Contraction of the second SMA wire 142 will apply a force to the second structure 13 in a negative direction -x, while contraction of the fourth SMA wire 144 will apply a force to the second structure 13 in a positive direction +x.

[0103] Other example configurations may be used, and further details are provided in WO 2017 / 055788 A1 and WO 2019 / 086855 A1, both of which are incorporated herein by this reference in their entireties.

[0104] The position of the second structure 13 relative to the first structure 12 perpendicular to the optical axis O (aligned with the z-axis as shown) is controlled by selectively changing the temperature of the SMA wires 141, 142, 143, 144. This is achieved by passing a selective drive signal through the SMA wires 141, 142, 143, 144 to provide resistive heating. The heating is provided directly by the drive current. Cooling is provided by reducing or stopping the drive current to allow the SMA wires 141, 142, 143, 144 to cool by conduction, convection and radiation with their surroundings.

[0105] In operation, the SMA wires 141, 142, 143, 144 are selectively driven to move the second structure 13 relative to the first structure 12 (or the first structure 12 relative to the second structure 13) in any lateral direction (i.e., in a direction within a plane parallel to the first axis x and the second axis y and perpendicular to the optical axis O and the third axis z).

[0106] Further details are also provided in WO 2013 / 175197 A1, which is incorporated herein by this reference.

[0107] Taking a set of four SMA wires 141, 142, 143, 144 as an example, the SMA wires 141, 142, 143, 144 are arranged in a loop at different angular positions around the optical axis O (corresponding to the third axis z here) to provide two pairs of opposing SMA wires 141 and 143, 142 and 144 that are substantially perpendicular to each other. Therefore, each pair of opposing SMA wires 141 and 143, 142 and 144 can selectively drive the second structure 13 to move in one of two perpendicular directions orthogonal to the optical axis O. Therefore, the SMA wires 141, 142, 143, 144 can be selectively driven to move the second structure 13 relative to the first structure 12 to any position within a range of movement within a plane orthogonal to the optical axis O. Another way to view the movement is that contraction of any pair of adjacent SMA wires (e.g., SMA wires 143, 144) will cause the second structure 13 to move in a direction that bisects the pair of SMA actuator wires (in a direction that bisects the pair of SMA actuator wires). Figure 3 The magnitude of the range of motion depends on the geometry and range of contraction of the SMA wires 141, 142, 143, 144 within their normal operating parameters. Rotation of the second structure 13 relative to the first structure 12 may be made possible by driving a single pair of opposing SMA wires (e.g., 141 and 143) while allowing the other SMA wires 142, 144 to be extended.

[0108] Typically, four SMA wires 141 , 142 , 143 , 144 may be driven to cause movement of the second structure 13 relative to the first structure 12 , which is a combination of DOFs Tx, Ty, and Rz.

[0109] When one of the SMA wires 141, 142, 143, 144 is heated, the stress in the SMA wire 141, 142, 143, 144 increases and the SMA wire contracts, causing the second structure 13 to move relative to the first structure 12. A series of movements occur as the temperature of the SMA increases within the temperature range where the SMA material transitions from the martensite phase to the austenite phase. Conversely, when one of the SMA wires 141, 142, 143, 144 is cooled so that the stress in the SMA wire 141, 142, 143, 144 is reduced, the SMA wire expands under the force from the opposing SMA wire of the SMA wires 141, 142, 143, 144 (and in some examples, the biasing force from one or more biasing devices such as springs, armatures, etc.). This allows the second structure 13 to move in the opposite direction relative to the first structure 12.

[0110] The SMA wires 141 , 142 , 143 , 144 may be made of any suitable SMA material, such as Nitinol or another titanium alloy SMA material.

[0111] The drive signals for the SMA wires 141, 142, 143, 144 are generated and provided by the control circuit implemented in the IC 7. For example, if the first structure 12 is fixed to the support structure 3 (or a portion of the support structure 3) and the second structure 13 is fixed to the lens assembly 4 (or a portion of the lens assembly 4), the drive signal is generated by the control circuit in response to the output signal of the gyro sensor (not shown) to drive the lens assembly 4 to move to stabilize the image focused on the image sensor 6 by the lens assembly 4, thereby providing OIS. The drive signal can be generated using, for example, the resistive feedback control technique described in WO 2014 / 076463 A1, which is incorporated herein by this reference.

[0112] Also refer to Figure 4 , an example of a “flat” SMA actuator assembly 15 implementing the drive device 11 is shown.

[0113] In the flat actuator assembly 15, the first structure 12 takes the form of a flat annular plate 16 having a rectangular outer perimeter (or "outer edge") and a circular inner perimeter (or "inner edge"), while the second structure 13 takes the form of a flat thin annular sheet 17 having a rectangular outer perimeter and a circular inner perimeter. The first structure 12 in the form of a plate 16 is supported on a base 5 in the form of a rectangular plate ( Figure 4 Not shown, see Figure 1 ). The four SMA wires 141, 142, 143, 144 are each attached at one end to a respective first crimp 181, 182, 183, 184 (also referred to as a "static" crimp) that is fixedly attached to (or forms part of) the first structure 12, 16. The other end of each SMA wire 141, 142, 143, 144 is attached to a respective second crimp 191, 192, 193, 194 (also referred to as a "moving" crimp) that is fixedly attached to (or forms part of) the second structure 13, 17.

[0114] The plate 16 and sheet 17 may each take the form of a respective patterned metal sheet (e.g. etched or machined stainless steel) and may be coated with an electrically insulating dielectric material. The plate 16 and sheet 17 are each provided with a respective central hole aligned with the optical axis O, allowing light to pass from the lens assembly 4 mounted to the sheet 17 to the image sensor 6 supported on the base 5 ( Figure 4 Not shown - see Figure 1 ).

[0115] The four SMA wires 141, 142, 143, 144 may be perpendicular to the optical axis O or at a small angle to a plane perpendicular to the optical axis O. "Small angle" may generally mean less than 20 degrees, less than 10 degrees, or even less than 5 degrees in some cases. Typically, in a group, the four SMA wires 141, 142, 143, 144 are not co-linear. The four SMA wires 141, 142, 143, 144 are preferably co-planar.

[0116] The flat actuator assembly 15 includes a plurality of sliding bearings ( Figure 4 (not shown) to support the second structure 13, 17 on the first structure 12, 16. Preferably, at least three supports are used to help provide stable support, but a different number of supports may be used in general. Sliding support ( Figure 4 The support member (not shown) may take the form of a support member in the form of a cylinder and may be attached to the first structure 12 or form a part of the first structure 12. Figure 4 The sliding bearing (not shown) may be made of a suitable metal or alloy (e.g. phosphor bronze or stainless steel with a diamond-like carbon coating). Figure 4 The PTFE (not shown) may be made of a polymer, or may include an upper coating of a polymer, such as polyoxymethylene (POM, acetal), polytetrafluoroethylene (PTFE), or PTFE-impregnated POM.

[0117] The flat actuator assembly 15 will typically also include a biasing device (not shown), such as one or more springs or flexure arms, arranged and configured to maintain the first structure 12 and the second structure 13 in contact (via a sliding support) and / or to urge the first structure 12 and the second structure 13 toward a neutral (e.g., central) relative position when the SMA wires 141, 142, 143, 144 are not energized.

[0118] Details related to manufacturing an actuator assembly similar to the flat actuator assembly 15 may be found in WO 2016 / 189314 A1, which is incorporated herein by reference in its entirety.

[0119] Although in Figure 4 Although not shown in the drawings, the flat actuator assembly 15 may be provided with end stops to provide a limit to lateral movement of the second structure 13 relative to the first structure 12. In this way, the SMA wires 141, 142, 143, 144 may be protected from excessive extension due to, for example, an impact that a device (not shown) incorporating the flat actuator assembly 15 may be subjected to (e.g., being dropped).

[0120] The drive means 11 can drive a translation Tx along the first axis x and / or a translation Ty along the second axis y and a rotation Rz around an axis parallel to a third axis z, which is substantially parallel to the optical axis O. However, in order to provide the translation Tz parallel to the third axis z, the first drive means 11 must be combined with at least one support capable of converting a torque applied around the optical axis O into a combination of rotation Rz and translation Tz (helical movement).

[0121] One or more of the movements driven by the drive device 11 may be fully or partially constrained by coupling one or more further supports between the first structure 12 and the second structure 13 .

[0122] Support

[0123] Most SMA actuators 2 according to the present description comprise at least one pair of drive means 11 and one or more mechanical supports (also referred to as “support means”) for supporting, constraining and / or translating the movement generated by the drive means 11 .

[0124] - Planar support -

[0125] Also refer to Figure 5A and Figure 5B , a planar support 20 (also called a three-point support) is shown.

[0126] Figure 5A is a side view, and Figure 5B It is a decomposed projection diagram.

[0127] The planar support 20 comprises a first plate 21 sliding in contact with a second plate 22. The first plate 21 supports at least three cylindrical protrusions 23, including at least a first cylindrical protrusion 231, a second cylindrical protrusion 232 and a third cylindrical protrusion 233, which are not collinear, for example, arranged at the vertices of a triangle. The second plate 22 is biased by a biasing device ( Figure 5A and Figure 5B The first plate 21 and the second plate 22 are pushed into contact with the flat surface of the cylindrical protrusion 23 and are free to slide in planes parallel to the first axis x and the second axis y, and rotate about an axis parallel to the third axis z. In this way, the relative movement between the first plate 21 and the second plate 22 corresponds to Tx, Ty and / or Rz. Unless the biasing force that pushes the plates 21, 22 together is overcome, the Tz, Rx and Ry movements are constrained.

[0128] exist Figure 5A and Figure 5BIn the example shown, both plates 21, 22 take the form of rings having a rectangular outer perimeter and a circular inner perimeter defining a central hole 24. However, the shape of the plates 21, 22 is irrelevant to the function of the planar support 20 and plates of any shape may be used instead. Figure 5A and Figure 5B Three cylindrical protrusions 231 , 232 , 233 are shown in FIG. 1 , but generally any number of cylindrical protrusions greater than or equal to three may be used.

[0129] The alternative planar bearing (not shown) is identical to the planar bearing 20 except that the three or more cylindrical protrusions 23 are replaced by three or more ball bearings (not shown). Either or both of the plates 21, 22 may include grooves (not shown) to define runs for receiving corresponding ball bearings (not shown). The alternative planar bearing is a rolling bearing rather than a sliding bearing.

[0130] - Helical Flexure Bearing -

[0131] Also refer to Figure 6 , an example of a helical support in the form of a helically curved support 25 is shown.

[0132] The helical flexure bearing 25 comprises a circular ring 26 having a central hole 24 and connected to three, four or more, preferably five or more helical beam sections 27. Figure 6 In the example shown, there are four spiral beam sections 271, 272, 273, 274. At the end not connected to the circular ring 26, each spiral beam section 271, 272, 273, 274 is connected to a pad 281, 282, 283, 284, for example for connection to a layer or structure below the circular ring 26 (relative to the third axis z drawn).

[0133] Each spiral beam portion 271, 272, 273, 274 is approximately tangent to the circular ring 26 (in the same direction), and its span includes a first component parallel to a plane containing the first axis x and the second axis y and a second component parallel to the third axis z. If the pads 281, 282, 283, 284 are clamped and a force is applied upward (positive z direction) to the circular ring 26, then in response, the spiral beam portions 271, 272, 273, 274 will deflect in the direction of that force. However, in doing so, the ends connected to the circular ring 26 are also deflected closer to the corresponding pads 281, 282, 283, 284, causing the circular ring 26 to rotate clockwise around an axis parallel to the third axis z. Conversely, a force applied downward (negative z direction) to the circular ring 26 will result in a downward movement of the circular ring 26 and a counterclockwise (anti-clockwise) rotation of the circular ring 26.

[0134] In this manner, the helical flexure bearing 26 acts to convert rotation about the third axis into relative displacement parallel to the third axis and vice versa. However, these movements are not independent of one another and the circular ring 26 is constrained to move along a path that approximates a spiral relative to the clamped pads 281, 282, 283, 284. Since this does not reflect independent degrees of freedom, the motion will be expressed as [Tz, Rz] to highlight the relationship between the translation Tz parallel to the third axis z and the rotation Rz about the third axis z for this type of bearing.

[0135] although Figure 6 The spiral beam portions 271, 272, 273, 274 shown in the figure are curved, however, in other examples of the spiral flexure bearing 25, the spiral beam portion 27 can be straight. Further examples of the spiral flexure bearing 25 are described in WO 2019 / 243849 A1, the contents of which are incorporated herein by reference in their entirety. Figures 19 to 22 of WO 2019 / 243849 A1 and the accompanying description on page 22, line 23 to page 23, line 24 are particularly relevant to the spiral flexure bearing 25. Further examples of implementing the spiral flexure bearing 25 are also shown and described below.

[0136] -Spiral sliding bearing-

[0137] Also refer to Fig. 7A and Figure 7B , an example of a helical bearing in the form of a helical sliding bearing 29 is shown.

[0138] Fig. 7A is a decomposed projection, and Figure 7B is a projection of the assembled spiral sliding bearing 29. Fig. 7A The occluded features are shown with dashed lines.

[0139] The spiral sliding bearing 29 includes a first structure 30 and a second structure 31, which are configured to fit together to perform sliding motion between spiral surfaces 321, 322 of the first structure 30 and spiral surfaces 331, 332 of the second structure 31. A biasing device (not shown) pushes the first structure 30 and the second structure 31 together to maintain contact between the paired spiral surfaces 321 and 322, 331, 332. In this way, the relative motion between the first structure 30 and the second structure 31 is constrained to the spiral path [Tz, Rz].

[0140] Fig. 7A and Figure 7BThe examples shown in the prior art prioritize visual clarity of the helical support function over feasibility of implementation, and the specific embodiments described below include additional examples that are more suitable for incorporation into a device such as camera 1. In particular, although the helical surfaces 32, 33 may be curved to follow the Fig. 7A and Figure 7B The spiral path shown, but in other examples, the spiral surfaces 32, 33 may be substantially planar, such as ramps. In a practical example, the first structure 30 may also include a central hole 24 to allow light to reach the image sensor 6 below.

[0141] although Fig. 7A and Figure 7B The spiral bearing shown in is a spiral sliding bearing, but other spiral bearings in the form of rolling bearings are also possible (see Fig.14 and Fig.15 ). Further examples of spiral supports can be found in WO 2019 / 243849 A1 (which has been incorporated by reference). See specifically WO 2019 / 243849 A1 Figure 1 to Figure 1 8 and the corresponding description from page 7, line 10 to page 22, line 21.

[0142] - Rotating support -

[0143] Also refer to Fig. 8A and Figure 8B , a rotating support 34 is shown.

[0144] Fig. 8A is a plan view of the rotary support 34, and Figure 8B It is along Fig. 8A A cross section along the line marked A-A' in FIG.

[0145] The rotary support 34 comprises a first plate 35 having a rectangular outer perimeter and a circular inner perimeter defining the central hole 24. A cylindrical portion 36 projects from the circular inner perimeter of the first plate 35 upwardly (in the positive z direction as shown in the figure).

[0146] exist Fig. 8A and 8B In the example shown, the cylindrical portion 36 is formed as a single piece with the first plate 35. However, the cylindrical portion 36 may alternatively be a separate piece that is received through the central hole 24 of the first plate 35. In this case, the outer diameter of the cylindrical portion 36 should be just smaller than the diameter of the central hole 24 of the first plate 35 so that lateral (xy plane) movement of the cylindrical portion 36 is constrained by the first plate 35. When not formed as a single piece with the first plate 35, the cylindrical portion 36 may be fixed or attached to the first plate 35, but need not be located within the central hole 24 and may rotate freely within the central hole 24.

[0147] The rotary support 34 further comprises a second plate 37 having a rectangular outer perimeter and a circular inner perimeter defining the central hole 24. The second plate 37 is received on the cylindrical portion 36. The first plate 35 supports at least three cylindrical protrusions 23. Fig. 8A and Figure 8B The example shown in includes a first cylindrical protrusion 231, a second cylindrical protrusion 232, a third cylindrical protrusion 233, and a fourth cylindrical protrusion 234, which are arranged at points of a square arranged generally concentrically with the cylindrical portion 36. In general, any three cylindrical protrusions 23 that are not co-linear may be used in accordance with any configuration suitable for the sliding bearing 20. In other examples, the cylindrical protrusions 23 may be supported by the second plate 37, or by a combination of the first plate 35 and the second plate 37. In some examples, the cylindrical protrusions 23 may be replaced with ball bearings (not shown).

[0148] Similar to the sliding bearing 20, the second plate 37 of the rotating bearing 34 is rotatable relative to the first plate 35 about an axis parallel to the third axis z. However, unlike the sliding bearing 20, the cylindrical portion 36 constrains the second plate 37 of the rotating bearing 34 to slide in a plane parallel to the first axis x and the second axis y.

[0149] The second plate 37 can be biased by a biasing device ( Fig. 8A and Figure 8B The second plate 37 is pushed into contact with the flat surface of the cylindrical protrusion 23. If a biasing device is included, the resulting biasing force that pushes the plates 35, 37 together must be overcome before movement Tz parallel to the z-axis can occur. In some examples, the cylindrical portion 36 may include a lip arranged to retain the second plate 37.

[0150] -Replaceable spiral bearings-

[0151] Also refer to FIG. 8C to FIG. 8F , an alternative spiral bearing 100 is shown.

[0152] Figure 8C A perspective exploded view of the support 100 is shown, and Figure 8D-8F Perspective views of the support 100 are shown in first ("lower"), second ("middle"), and third ("upper") configurations, respectively.

[0153] The support 100 includes an upper plate 101, a lower plate 102 and a set of four ball bearing elements 1031-1034. Each plate 101, 102 has a generally annular shape and is oriented parallel to the xy plane and centered on the z-axis. Each plate 101, 102 includes four cut-out sections 1041-1044, 1051-1054. Each cut-out section 104, 105 is "teardrop" shaped in that it has a tip and a circular (approximately semicircular) end. The cut-out sections 104, 105 in the upper plate 101 and the lower plate 102 can have the same shape. The cut-out sections 104 in the upper plate 101 are spaced apart at 90° intervals around the plate 101, extending in a circumferential direction in a manner such that their tips are oriented in a counterclockwise direction (in this example). Similarly, the cutout sections 105 in the lower plate 102 are spaced at 90° intervals around the plate 102 and extend in the circumferential direction. However, the tips of the cutout sections 105 in the lower plate 102 are oriented in a clockwise direction. The dimensions are such that the ball bearing elements 103 can only partially pass through the cutout sections 104, 105. When assembled, each ball bearing element 103 is located in a pair of cutout sections 104, 105 between the upper plate 101 and the lower plate 102.

[0154] As described above, a biasing force is applied to push the plates 101, 102 towards each other. In the absence of any further force, the support 100 will take Fig.8D The first ("downward") position is shown, in which each ball bearing element 103 is positioned toward the (wider) circular end of each cut-out segment 104, 105, and each ball bearing element 103 is positioned relatively deeply in each cut-out segment 104, 105. Thus, the plates 101, 102 are positioned relatively close to each other. The circular ends of the cut-out segments 104, 105 that retain the ball bearing elements 103 prevent further movement of the plates 101, 102 toward each other. When a torque is applied to rotate the upper plate 101 in a clockwise direction (in this example) relative to the lower plate 102, this causes the ball bearing elements 103 to roll along each cut-out segment 104, 105 toward the (narrower) tip, and thereby causes each ball bearing element 103 to be positioned less deeply in each cut-out segment 104, 105, and the plates 101, 102 to move away from each other. See. Fig. 8E End stops or other suitable devices (not shown) may limit the maximum rotation and / or spacing of the plates 101, 102. Figure 8F .

[0155] Thus, the support 100, which can be manufactured relatively easily, provides for example Figure 6 and Figure 7A-7B25 , 29 shown in and may be used in place of these supports 25 , 29 in any of the examples described herein.

[0156] Different shapes of cut-out sections may be used instead of those described above. In principle, any cut-out section that tapers from one end to the other may be used. Some such designs may require additional end stops. The cut-out sections 104, 105 do not need to correspond to holes through the plates 101, 102 and may, for example, correspond to recesses or even be formed in local raised portions of the plates 101, 102 (or any formed part).

[0157] There may be a different number of ball bearing elements 103, such as three, or more than four, such as eight or twelve. Having a greater number of ball bearing elements 103 may help avoid collapse of the ball bearing elements 103 or the plates 101, 102, such as due to an impact event (due to a greater contact area).

[0158] In some examples, panels 101 , 102 may be configured to be sufficiently flexible, at least adjacent cutout sections 104 , 105 , to enable them to deflect when subjected to high forces associated with an impact event, which may also help avoid such collapse.

[0159] In some examples, plates 101, 102 may be made of a ferromagnetic material (eg, steel), and ball bearing element 103 may be magnetic. This configuration may reduce or avoid the need for a biasing force.

[0160] Although shown and described for reference purposes in a particular orientation relative to a set of right-handed Cartesian axes x, y, z, any of the supports described above may be oriented at any angle.

[0161] The support described above can be formed by any suitable material and using any suitable manufacturing method. For example, a plate-like or sheet-like component can be made of a metal sheet (e.g., stainless steel) and patterned by chemical or laser etching. Milling or stamping can be used as long as this does not unacceptably introduce residual strains that cause part deformation. After patterning, these parts can be bent or pre-deformed as needed. Complex three-dimensional parts can be constructed by attaching parts to plates, sheets or other parts, such as using adhesives, welding, brazing, soft soldering, etc. Alternatively, complex three-dimensional parts can be formed by, for example, sintering or die casting of a metal or by injection molding of a polymer. Any supporting surface can be formed by a polymer (e.g., POM (acetal), PTFE or PTFE-impregnated POM).

[0162] First actuator assembly

[0163] Also refer to Fig. 9 , Fig.10 and Fig.11 , a first actuator assembly 38 is schematically illustrated.

[0164] The first actuator assembly 38 is in the form of eight SMA wire actuators. The first actuator assembly 38 can be viewed as two planes of four SMA wire actuators connected by a support device that converts a torque applied about an axis parallel to a first direction (as shown, the first direction is parallel to the z-axis) into movement along the first direction z. Therefore, the two planes of four SMA wire actuators can work together to increase movement along the first direction.

[0165] The first actuator assembly 38 includes a first portion 39 , a second portion 40 , a first support device 41 , a first four-wire driving device 42 , a third portion 43 , a second support device 44 , and a second four-wire driving device 45 .

[0166] A first support device 41 mechanically couples the first part 39 to the second part 40. The second part 40 is movable relative to the first part perpendicular to an optical axis 46 (or "principal axis" - which is parallel to the first direction z) passing through the actuator assembly 38, and is rotatable relative to the first part 39 about the principal axis 46 (parallel to the first direction z).

[0167] The first drive device 42 includes a total of four shape memory alloy wires 471, 472, 473, 474 (also referred to herein as "segments"). The four shape memory alloy wires 471, 472, 473, 474 mechanically connect (or "couple") the second portion 40 of the actuator assembly to the first portion 39 of the actuator assembly. The shape memory alloy wires 471, 472, 473, 474 are formed of copper-aluminum-nickel alloy, nickel-titanium alloy, or other suitable shape memory alloys.

[0168] The second support means 44 mechanically couples the second part 40 to the third part 43. The third part 43 is movable relative to the second part 40 and the first part 39 along a main axis 46 (parallel to the first direction z).

[0169] The second drive device 45 includes a total of four shape memory alloy wires 481, 482, 483, 484. The four shape memory alloy wires 481, 482, 483, 484 mechanically connect the third portion 43 of the actuator assembly 38 to the first portion 32. The shape memory alloy wires 481, 482, 483, 484 are formed of copper-aluminum-nickel alloy, nickel-titanium alloy or other suitable shape memory alloys.

[0170] -First four SMA wire actuators 49-

[0171] Specific reference Fig. 9 The actuator assembly 38 comprises substantially the same as described above with respect to Figure 4 The first flat four SMA wire actuator 49 (see drive device 11).

[0172] The first portion 39 of the actuator assembly 38 provides the first structure 12 of the first four SMA wire actuator 49 and takes the form of a flat annular plate having a rectangular outer perimeter (or “outer edge”) and a circular inner perimeter (or “inner edge”).

[0173] The second portion 40 of the actuator assembly 38 provides the second structure 13 of the first four SMA wire actuator 49 and takes the form of a flat, thin annular sheet having a rectangular outer perimeter and a circular inner perimeter. The first portion 39 is supported on a base ( Fig.10 (not shown).

[0174] The four SMA wires 471, 472, 473, 474 are each attached at one end to a respective first crimp 501, 502, 503, 504 (also referred to as a "static" crimp) that is fixedly attached to (or forms part of) the first portion 39. The other end of each SMA wire 471, 472, 473, 474 is attached to a respective second crimp 511, 512, 513, 514 (or "moving crimp") that is fixedly attached to (or forms part of) the second portion 40.

[0175] As explained above, the first portion 39, the second portion 40 and the third portion 43 may each take the form of a respective patterned metal sheet, such as etched or machined stainless steel, and may be coated with an electrically insulating dielectric material. The first portion 39, the second portion 40 and the third portion 43 are each provided with a respective central hole aligned with the optical axis (primary axis) 46, allowing light to pass from the lens assembly ( Fig.10 not shown) to the support on the base ( Fig. 9 Passing of an image sensor (not shown) on the image sensor (not shown).

[0176] The four SMA wires 471, 472, 473, 474 can be arranged perpendicular to the optical axis (main axis) 46 (parallel to the first direction z), or can be inclined at a small angle relative to a plane perpendicular to the light 46. "Small angle" can generally mean less than 20 degrees, less than 10 degrees, or even less than 5 degrees in some cases. Typically, in a group, the four SMA wires 471, 472, 473, 474 are not collinear.

[0177] The flat four SMA wire actuator 49 comprises two arms 52 connected between the first portion 39 and the second portion 40. The arms 52 are resilient and configured to provide a suitable holding force along the optical axis 46 (parallel to the first direction z) and also allow lateral movement with a suitable lateral biasing force.

[0178] In the assembled state of the actuator assembly, the arms 52 are deflected from their relaxed state so that the arms 52 provide a force (i.e., a retaining force) that biases the first and second parts 39, 40 together to maintain contact in the first bearing means 41, which in this example takes the form of a sliding bearing 20. At the same time, the arms 52 can be deflected laterally to allow the second part 40 to move relative to the first part 39 in a direction perpendicular to the optical axis 46 (which is parallel to the first direction).

[0179] The arm 52 provides a force (i.e., a lateral biasing force) that biases the second portion 40 toward the center position from any direction about the center position, where the center position corresponds to the optical axis O of the lens assembly (not shown), which is substantially aligned with the center of the photosensitive area of ​​the image sensor (not shown).

[0180] Each arm 52 is generally "L" shaped and extends about the optical axis 46. The angular extent of each arm 52, as measured between the end points of the arm 52, is preferably at least 90°.

[0181] In this example, the arm 52 is integrally formed with the second portion 40 at one end thereof and connected at the other end thereof to the first portion 39. Alternatively, the arm 52 may be integrally formed with the first portion 39 and connected to the second portion 40, or the arm 52 may be a separate portion connected to both the first portion 39 and the second portion 40. The arm 52 may be connected to the plates 39, 40 by welding, which provides both a mechanical connection and an electrical connection.

[0182] The arm 52 is made of a suitable material that provides the desired mechanical properties and is electrically conductive. Typically, the material is a metal with a relatively high yield, for example steel, such as stainless steel.

[0183] The first flat actuator assembly 49 comprises a plurality of sliding bearings ( Fig. 9 (not shown) to support the second portion 40 on the first portion 39. Preferably, at least three supports are used to help provide stable support, but a different number of supports may be used in general. Sliding support ( Fig. 9 The support member (not shown) may take the form of a cylindrical support member and may be attached to the first portion 39 or formed as part of the first portion 12. Fig. 9The sliding bearing (not shown) may be made of a suitable metal or alloy (e.g. phosphor bronze or stainless steel with a diamond-like carbon coating). Fig. 9 The sliding bearing (not shown) may be made of a polymer or may include an upper coating of a polymer such as polyoxymethylene (POM, acetal), polytetrafluoroethylene (PTFE) or PTFE-impregnated POM. Fig. 9 ) may be the same or similar to the cylindrical protrusion 23 of the sliding support 20 (see Figure 5A and Figure 5B ).

[0184] -Second four SMA wire actuator 53-

[0185] Still reference Fig. 9 , the actuator assembly 38 includes a second flat four SMA wire actuator 53 .

[0186] The first portion 39 of the actuator assembly 38 provides the first structure 12 of the second four SMA wire actuator 53. The third portion 43 of the actuator assembly 38 provides the second structure 13 of the second four SMA wire actuator 53 and takes the form of a flat, thin annular sheet having a rectangular outer perimeter and a circular inner perimeter.

[0187] The four SMA wires 481, 482, 483, 484 are each attached at one end to a respective first crimp 541, 542, 543, 544 (also referred to as a "static" crimp) that is fixedly attached to (or forms part of) the first portion 39. The other end of each SMA wire 481, 482, 483, 484 is attached to a respective second crimp 551, 552, 553, 554 (or a "moving crimp") that is fixedly attached to (or forms part of) the third portion 43.

[0188] The static crimping portions 541, 542, 543, 544 are arranged with the first static crimping portion 541 and the fourth static crimping portion 544 disposed in the first corner 561 (corresponding to the first SMA wire 481 and the fourth SMA wire 484) and the second static crimping portion 542 and the third static crimping portion 543 disposed in the diagonally opposite third corner 563 (corresponding to the second SMA wire 482 and the third SMA wire 483). Similarly, the first mobile crimping portion 551 and the second mobile crimping portion 552 are disposed at the second corner 562 (corresponding to the first SMA wire 481 and the second SMA wire 482), and the third mobile crimping portion 553 and the fourth mobile crimping portion 554 are disposed at the diagonally opposite fourth corner (corresponding to the third SMA wire 481 and the fourth SMA wire 482).

[0189] The second flat four SMA wire actuator 53 is raised upright from the first portion 39 of the actuator assembly 38 in two diagonally opposed corners 561, 563 by two pairs of walls 571, 572, 573, 574 (or "panels" or "posts"). The walls 571, 572, 573, 574 are vertical in each pair, located on different sides of the plate-like first portion 39. Each wall 571, 572, 573, 574 has a corresponding inwardly extending shelf portion (or "tab") to which the static crimp 541, 542, 543, 544 is attached (by welding, adhesive or other suitable attachment method).

[0190] -Second Support Device 44-

[0191] Still reference Fig. 9 The actuator assembly 38 includes a second support means 44 in the form of a helical flexure support 25, which is substantially as described above with respect to Figure 6 described.

[0192] The second support device 44 comprises a circular ring 58 having a central hole 24 and connected to three, four or more, preferably five or more spiral beam portions 59. Fig. 9 In the example shown, there are four spiral beam sections 591, 592, 593, 594. The spiral beam section 59 is substantially the same as Figure 6 The helical beam portions 27 of the helical flexible bearing 25 shown in FIG. 5 are identical. At the end not connected to the annular ring 58, each helical beam portion 591, 592, 593, 594 is connected to a respective pad 601, 602, 603, 604, for example for connection to the second portion 40.

[0193] Each helical beam portion 591, 592, 593, 594 is approximately tangential to the circular ring 58 (in the same orientation) and has a span that includes a first component parallel to a plane containing the first axis x and the second axis y and a second component parallel to the third axis z / first direction z (parallel to the main axis or optical axis 46). If the pads 601, 602, 603, 604 are clamped or otherwise secured and a force is applied upward (positive z direction) to the circular ring 58, then in response the helical beam portions 591, 592, 593, 594 will deflect in the direction of that force. However, in doing so, the ends connected to the circular ring also deflect closer to the respective pads 601, 602, 603, 604, causing the circular ring 58 to rotate clockwise about an axis parallel to the third axis z / first direction z. Conversely, a force applied downward (negative z-direction) to the annular ring 58 will result in downward movement of the annular ring 58 and counterclockwise (counterclockwise) rotation of the annular ring 58 .

[0194] The pads 601 , 602 , 603 , 604 of the second bearing means 44 in the form of helical flexure bearings are attached to the second part 40 , for example by welding, adhesive or other suitable attachment methods.

[0195] A hollow cylinder 61 with a central hole is fixed to the annular ring 58 of the second support means 44 in the form of a spiral flexure. The hollow cylinder 61 provides a space for mounting one or more lenses ( Fig. 9 The hollow cylinder 61 is mounted to the lower surface 62 of the circular ring 58 (relative to the first direction z) and rests on the lower surface 62 of the circular ring 58 of the second support device 44 (relative to the first direction z). The length of the hollow cylinder 61 along the optical axis 46 (i.e., the length along the first direction z) causes the bottom of the hollow cylinder 61 to be separated from the base ( Fig. 9 ) and an image sensor (not shown) mounted thereon Fig. 9 not shown).

[0196] The upper surface 63 (relative to the first direction z) of the annular ring 58 is fixed to the third part 43, which in this case takes the form of an annular rigid frame. Fig. 9 and Fig.10 In the example shown, the third portion 43 has a generally rectangular outer perimeter and an inner perimeter defining a central aperture.

[0197] A cover 64 (also referred to as a "shield") is mounted over the actuator assembly 38 to protect and contain the various components. Fig.10 The cover 64 is omitted from the assembled view of FIG.

[0198] Second actuator assembly

[0199] Also refer to Fig.12 , Fig.13A and Fig. 13B , a second actuator assembly 65 is schematically shown.

[0200] Fig.12 is a schematic plan view of the second actuator assembly 65 . Fig.13A is along Fig.12 Schematic cross section along the diagonal line BB' shown in FIG. Fig. 13B is along Fig.12 Schematic cross section of line CC' shown in .

[0201] The second actuator assembly 65 takes the form of eight SMA wire actuators. The second actuator assembly 65 is similar to the first actuator assembly 38, except that the shape and configuration of some parts have been modified to reduce the height of the second actuator assembly 65 along the optical axis (primary axis) 46 (again parallel to the first direction aligned with the third axis z, as shown). In particular, Fig.11 The block diagram shown in FIG. 6 applies equally to the second actuator assembly 65 as it does to the first actuator assembly 38 .

[0202] -First four SMA wire actuators 66-

[0203] Specific reference Fig.12 , the second actuator assembly 65 includes a first flat four SMA wire actuator 66 .

[0204] The first portion 39 of the second actuator assembly 65 provides the first structure 12 of the first four SMA wire actuator 66 and takes the form of a flat annular plate having a rectangular outer perimeter (or “outer edge”) and a circular inner perimeter (or “inner edge”).

[0205] The second part 40 of the second actuator assembly 65 provides the second structure 13 of the first four SMA wire actuator 66 and takes the form of a flat, thin annular sheet having a diamond-shaped outer perimeter and a circular inner perimeter. The first structure 39 is supported on a base ( Figures 12 to 13B (not shown).

[0206] The four SMA wires 471, 472, 473, 474 are each attached at one end to a respective first crimp 501, 502, 503, 504 (also referred to as a "static" crimp) that is fixedly attached to (or forms part of) the first portion 39. The other end of each SMA wire 471, 472, 473, 474 is attached to a respective second crimp 511, 512, 513, 514 (or a "moving crimp") that is fixedly attached to (or forms part of) the second portion 40. The moving crimps 511, 514 are disposed on one corner of the second actuator assembly 65, with additional moving crimps 512, 513 disposed on diagonally opposite corners. Compared to the first actuator assembly 38 , the four SMA wires 471 , 472 , 473 , 474 have reduced lengths along directions x, y perpendicular to the optical axis (primary axis) 46 (parallel to the first direction).

[0207] As explained above, the first portion 39 and the second portion 40 may each take the form of a respective patterned metal sheet, such as etched or machined stainless steel, which may be coated with an electrically insulating dielectric material. The first portion 39 and the second portion 40 are each provided with a respective central hole aligned with the optical axis (principal axis) 46 (parallel to the first direction), allowing light to pass from the lens assembly ( Figures 12 to 13B not shown) to the support on the base ( Figures 12 to 13B Passage of an image sensor (not shown) on the image sensor (not shown).

[0208] The four SMA wires 471, 472, 473, 474 can be perpendicular to the optical axis 46 (parallel to the first direction z), or can be inclined at a small angle relative to a plane perpendicular to the light ray 46. "Small angle" can generally mean less than 20 degrees, less than 10 degrees, or even less than 5 degrees in some cases. Typically, in a group, the four SMA wires 471, 472, 473, 474 are not collinear.

[0209] Similar to the arms 52 of the first actuator assembly 38, the first four SMA wire actuator 66 of the second actuator assembly 65 includes two or more arms ( Figures 12 to 13B The arm (not shown) 52 is resilient and configured to provide a suitable retaining force along the optical axis 46 (parallel to the first direction z) and also allow lateral movement with a suitable lateral biasing force.

[0210] In the assembled state of the actuator assembly, the arm ( Figures 12 to 13B ) is deflected from its relaxed state so that the arm ( Figures 12 to 13B ) provides a force (ie, a retaining force) that biases the first portion 39 and the second portion 40 together and maintains the sliding support ( ) of the first support device 41 providing the second actuator assembly 65 Figures 12 to 13B At the same time, the arm ( Figures 12 to 13B The second portion 40 (not shown) can be laterally deflected to allow the second portion 40 to move relative to the first portion 39 in a direction perpendicular to the optical axis 46 (parallel to the first direction z).

[0211] arm( Figures 12 to 13B ) provides a force (i.e., a lateral biasing force) that biases the second portion 40 from any direction about the center position toward the center position, wherein the center position corresponds to the lens assembly ( Figures 12 to 13B ) is substantially aligned with the optical axis 46 of the image sensor ( Figures 12 to 13B Center alignment of the photosensitive area (not shown).

[0212] Each arm ( Figures 12 to 13B ) may be generally "L" shaped and extend around the optical axis 46 (parallel to the first direction z). Figures 12 to 13B Measured between the endpoints of each arm (not shown) Figures 12 to 13B The angular range (not shown) is preferably at least 90°.

[0213] In this example, the arm (at Figures 12 to 13B ) is integrally formed with the second portion 40 at one end thereof and connected to the first portion 39 at the other end thereof. Alternatively, the arm ( Figures 12 to 13B) may be integrally formed with the first portion 39 and connected to the second portion 40, or the arm ( Figures 12 to 13B The arm (not shown) may be a separate part connected to both the first part 39 and the second part 40. Figures 12 to 13B ) can be connected to the first part 39 and / or the second part 40 by welding, which can provide mechanical and electrical connections.

[0214] arm( Figures 12 to 13B The PCB (not shown) is made of a suitable material that provides the required mechanical properties and is electrically conductive. Typically, the material is a metal with a relatively high yield, such as steel, such as stainless steel.

[0215] The first four SMA wire actuator 66 includes a plurality of sliding bearings ( Figures 12 to 13B (not shown) to support the second structure 40 on the first structure 39. Preferably, at least three supports are used to help provide stable support, but a different number of supports may be used in general. Sliding support ( Figures 12 to 13B 39) may take the form of a cylindrical support member and may be attached to or formed as part of the first portion 39, for example the same or similar to the cylindrical protrusion 23 of the sliding bearing 20 (see Figure 5A and Figure 5B ). Sliding bearing ( Figures 12 to 13B The sliding bearing (not shown) may be made of a suitable metal or alloy (e.g. phosphor bronze or stainless steel with a diamond-like carbon coating). Figures 12 to 13B The PTFE (not shown) may be made of a polymer, or may include an upper coating of a polymer, such as polyoxymethylene (POM, acetal), polytetrafluoroethylene (PTFE), or PTFE-impregnated POM.

[0216] -Second four SMA wire actuator 67-

[0217] Still specific reference Fig.12 , the second actuator assembly 65 includes a second flat four SMA wire actuator 67 .

[0218] The first portion 39 of the second actuator assembly 65 provides the first structure 12 of the second four SMA wire actuator 67. The third portion 43 of the second actuator assembly 43 provides the second structure 13 of the second four SMA wire actuator 67 and takes the form of a flat, thin annular sheet having a circular outer perimeter and a circular inner perimeter.

[0219] The four SMA wires 481, 482, 483, 484 are each attached at one end to a respective crimp 541, 542, 543, 544 (also referred to as a "static" crimp) that is fixedly attached to (or forms part of) the first portion 39. The other end of each SMA wire 481, 482, 483, 484 is attached to a respective second crimp 551, 552, 553, 554 (or a "moving crimp") that is fixedly attached to (or forms part of) the third portion 43. The moving crimps 551, 552 are disposed on one corner of the second actuator assembly 65, with additional moving crimps 553, 554 disposed on diagonally opposite corners. Compared to the first actuator assembly 38 , the four SMA wires 481 , 482 , 483 , 484 have reduced lengths along directions x, y perpendicular to the optical axis (principal axis) 46 (parallel to the first direction z).

[0220] The third portion 43 includes a ring 68 that is positioned generally within a central hole in the second portion 40. First and second diagonally opposed walls 691, 692 (or "wings") extend outwardly and over the second portion 40 such that the moving crimps 551, 552, 553, 554 of the second four SMA wire actuator 67 are positioned outside the outer perimeter of the second portion 40.

[0221] Each arm (or wing) 691, 692 comprises a first portion 701, 702 and a second portion 711, 712 connected by a respective transition portion 721, 722 (see in particular Fig.13A ). The first portions 701, 702 are coplanar with the ring 68 and each extend beyond the perimeter of the second portion 40. The second portion 711 supports a pair of movable crimping portions 551, 552 and the second portion 712 supports another pair of movable crimping portions 553, 554. The second portions 711, 712 are offset (relative to the first direction z) below the ring 68 and the first portions 701, 702 so that the four SMA wires 481, 482, 483, 484 of the second four SMA wire actuator 67 are generally coplanar with the four SMA wires 471, 472, 473, 474 of the first four SMA wire actuator 66 (at least when the second actuator assembly 65 is not powered and is stationary in a center position). The transition portions 721, 722 are located at Fig.13AIn the example shown, the transition portion 72 extends parallel to the optical axis 46 (parallel to the first direction). In general, the transition portion 72 can have any shape that provides a desired offset between the first portion 70 and the second portion 71, and can be angled and / or curved relative to the optical axis 46. The first portion 70, the second portion 71, and the transition portion 72 can be formed from an initially planar arm (wing) 69, such as by bending or stamping. The first portion 70, the second portion 71, and the transition portion 72 need not be separated by discontinuities, and can take the form of a region of a continuously contoured arm (wing) 69.

[0222] The second actuator assembly 65 includes a first wall 731, a second wall 732, a third wall 733, and a fourth wall 734 that run along the perimeter of the first portion 39 and extend upward (relative to the first direction z). The walls 731, 732, 733, and 734 may be formed as a single piece with the first portion 39, or may be one or more separate parts that engage the plate of the first portion 39. A first tab 741, a second tab 742, a third tab 743, and a fourth tab 744 extend inwardly from the middle of each wall 731, 732, 733, and 734, which supports the static crimps 50, 54.

[0223] -Second Support Device 44-

[0224] Still specifically referring to Fig.12 The second actuator assembly 65 includes a second support device 44 in the form of a helical flexure bearing, which is substantially as described above with respect to Figure 6 As described above with respect to the first actuator assembly 38 and / or the helical flexure bearing 29 shown in .

[0225] The second support device 44 comprises a circular ring 58 having a central hole and connected to three, four or more, preferably five or more spiral beam portions 59 (in Fig.13A and Fig. 13B as seen in cross section in Figures 12 to 13B In the example shown, there are four spiral beam portions 591, 592, 593, 594. At the end not connected to the circular ring 58, each spiral beam portion 591, 592, 593, 594 is connected to a pad 601, 602, 603, 604. The second support device 44 of the second actuator assembly 65 may have the same or a reduced height along the optical axis (main axis) 46 (parallel to the first direction z) compared to the second support device 44 of the first actuator assembly 38, and is otherwise identical.

[0226] The pads 601 , 602 , 603 , 604 of the second bearing means 44 in the form of helical flexure bearings are attached to the second part 40 , for example by welding, adhesive or other suitable attachment methods.

[0227] A hollow cylinder 61 with a central hole (in Fig.13A and Fig. 13B The hollow cylindrical body 61 is provided for mounting one or more lenses ( Figures 12 to 13B The hollow cylinder 61 is mounted to the lower surface of the circular ring 58 (relative to the first direction z) and rests on the lower surface of the circular ring 58 of the second support device (relative to the first direction z). The length of the hollow cylinder 61 along the optical axis (main axis) 46 (parallel to the first direction z as shown) allows the bottom of the hollow cylinder 61 to be separated from the base and mounted on the base (not shown). Figures 12 to 13B ) on the image sensor ( Figures 12 to 13B not shown).

[0228] The upper surface (with respect to the first direction z) of the circular ring 58 is fixed to the underside of the third portion 43 .

[0229] cover( Figures 12 to 13B A shield cover (not shown) (also called a "shield cover") is assembled on the second actuator assembly 65 to protect and contain the various parts.

[0230] In a modification (not shown) of the second actuator assembly 65, each pair of static crimps 50, 54 supported on respective tabs 74 may be replaced by a single common crimp (not shown), and the corresponding pair of SMA wires 47, 48 may be replaced by a single length of SMA wire secured at either end to the moving crimps 51, 55 and secured in the middle by a (static) common crimp (not shown). The drive current in each half of the single length of SMA wire may be independently controlled by using the common crimp (not shown) as a common current sink (e.g., corresponding to system ground). Independent electrical connections to the moving crimps 51, 55 may be provided by respective flexures (not shown).

[0231] Third actuator assembly

[0232] Reference Fig.14 and Fig.15 , a third actuator assembly 75 is schematically illustrated.

[0233] The third actuator assembly 75 is in the form of eight SMA wire actuators. The third actuator assembly 75 is similar to the first actuator assembly 38, except that the second bearing device 44 is in the form of a spiral roller bearing rather than a spiral flexure bearing. In particular, Fig.11 The block diagram shown in FIG. 6 applies equally to the third actuator assembly 65 as it does to the first actuator assembly 38 .

[0234] -First four SMA wire actuators 76-

[0235] Specific reference Fig.14 The third actuator assembly 75 includes a first flat four SMA wire actuator 76, which is similar to the one described above with respect to Figure 4 The flat SMA actuator assemblies 15 described are substantially the same.

[0236] The first portion 39 of the third actuator assembly 75 provides the first structure 12 of the first four SMA wire actuator 76 and takes the form of a flat annular plate having a rectangular outer perimeter (or “outer edge”) and a circular inner perimeter (or “inner edge”).

[0237] The second portion 40 of the third actuator assembly 75 provides the second structure 13 of the first four SMA wire actuator 76 and takes the form of a flat, thin annular sheet having a rectangular outer perimeter and a circular inner perimeter. The first portion 39 is supported on a base ( Fig.14 and Fig.15 (not shown).

[0238] The four SMA wires 471, 472, 473, 474 are each attached at one end to a respective first crimp 501, 502, 503, 504 (also referred to as a "static" crimp) that is fixedly attached to (or forms part of) the first portion 39. The other end of each SMA wire 471, 472, 473, 474 is attached to a respective second crimp 511, 512, 513, 514 (or "moving crimp") that is fixedly attached to (or forms part of) the second portion 40.

[0239] As explained above, the first portion 39 and the second portion 40 may each take the form of a respective patterned metal sheet, such as etched or machined stainless steel, which may be coated with an electrically insulating dielectric material. The first portion 39 and the second portion 40 are each provided with a respective central hole aligned with the optical axis (principal axis) 46 (parallel to the first direction z), allowing light to pass from the lens assembly ( Fig.14 and Fig.15 not shown) is transferred to the support on the base ( Fig.14 and Fig.15 6 on the image sensor 6 (not shown).

[0240] The four SMA wires 471, 472, 473, 474 can be perpendicular to the optical axis 46 (parallel to the first direction z), or can be inclined at a small angle relative to a plane perpendicular to the light ray 46. "Small angle" can generally mean less than 20 degrees, less than 10 degrees, or even less than 5 degrees in some cases. Typically, in a group, the four SMA wires 471, 472, 473, 474 are not collinear.

[0241] The flat four SMA wire actuator 76 includes two arms 52 connected between the first portion 39 and the second portion 40 , and the arms 52 are configured identically to the arms 52 of the first four wire drive 42 of the first actuator assembly 38 .

[0242] The first four SMA wire actuator 76 comprises a plurality of sliding bearings ( Fig.14 and Fig.15 (not shown) to support the second structure 40 on the first structure 39. Sliding support ( Fig.14 and Fig.15 ) is the same as the sliding support of the first four-wire drive device 42 described above for the first actuator assembly 38.

[0243] -Second four SMA wire actuator 77-

[0244] Still specific reference Fig.14 , the third actuator assembly 75 includes a second four SMA wire actuators 77 .

[0245] The third portion 43 of the third actuator assembly 75 provides the second structure 13 of the second four SMA wire actuator 77 and takes the form of a flat, thin annular sheet having a rectangular outer perimeter and a circular inner perimeter. The first structure 12 of the second four SMA wire actuator 77 of the third actuator assembly 75 is provided by an extension plate 78 of the first portion 39 in the form of a flat, thin annular sheet having a rectangular outer perimeter and a circular inner perimeter.

[0246] The extension plate 78 is rigidly connected to the first portion 39. In this example, when the cover 64 (also referred to as a "shield") is assembled on the third actuator assembly 75 to protect and contain the various parts, both the first portion 39 and the extension plate 78 are attached to the cover 64 (e.g., by welding). For clarity, Fig.15 The cover 8 is omitted.

[0247] The four SMA wires 481, 482, 483, 484 are each attached at one end to a respective first crimp 541, 542, 543, 544 (also referred to as a "static" crimp) that is fixedly attached to (or forms part of) the extension plate 78. The other end of each SMA wire 481, 482, 483, 484 is attached to a respective second crimp 551, 552, 553, 554 (or a "moving crimp") that is fixedly attached to (or forms part of) the third portion 43.

[0248] In contrast to the first four SMA wire actuator 76, the second four SMA wire actuator 77 does not include any sliding bearings or flexure arms 52. Therefore, the third portion 43 is not held in contact with the extension plate 78, either directly or via a bearing. The height of the extension plate 78 above the first portion 39 (relative to the first direction z) should be set according to the desired travel distance of the third portion 43 along the optical axis 46 (parallel to the first direction z). Advantageously, the extension plate 78 can also serve as an end stop, which can help prevent the third portion 43 from over-traveling in response to an impact or a drop.

[0249] -Second Support Device 44-

[0250] Still reference Fig.14 Compared to the first and second actuator assemblies 38 and 65 which employ helical flexure bearings, the third actuator assembly 75 includes a second bearing device 44 in the form of a helical roller bearing 79 .

[0251] The second support device 4 in the form of a spiral roller bearing 79 comprises a first portion in the form of a lens holder 80 which performs the function of supporting the lens assembly ( Fig.14 and Fig.15 One or more lenses (not shown) Fig.14 and Fig.15 The spiral roller bearing 79 includes a ring 81 having a circular inner perimeter defining a central hole and an outer perimeter alternating between a rectangular and a circular profile. The ring 81 supports four inclined surfaces 821, 822, 823, 824 equidistant in a circle around the central hole of the ring 81. Each inclined surface 821, 822, 823, 824 takes the form of a rectangular frame having an elongated hole 831, 832, 833, 834 extending along the length of each inclined surface 821, 822, 823, 824. The inclined surfaces 821, 822, 823, 824 are all at substantially equal angles to the ring 81 (which is located in a plane parallel to the first axis x and the second axis y). When assembled, each elongated hole 831, 832, 833, 834 receives a corresponding ball bearing 841, 842, 843, 844.

[0252] The lens holder 80 is generally cylindrical about a central hole for mounting one or more lenses (not shown). The lens holder 80 also includes four protrusions 851, 852, 853, 854, which extend radially outward from the generally cylindrical lens holder 80. The first protrusion 851 defines a first bearing surface 861 in the form of a "V" shaped channel. The first bearing surface 861 is generally oriented upward (perpendicular to the first bearing surface 861 having a component generally in the positive +z direction along the first direction). The second protrusion 852 defines a corresponding bearing surface 862 in the form of a "V" shaped channel oriented generally downward (perpendicular to the second bearing surface 862 having a component generally in the negative -z direction along the first direction z). The third protrusion 853 and the fourth protrusion 854 define a third bearing surface 863 and a fourth bearing surface 864, respectively, each of which is in the form of an angled planar surface oriented generally upward (perpendicular to the third bearing surface 863 and the fourth bearing surface 864 having a component generally in the positive +z direction along the first direction z).

[0253] When assembled, each bearing surface 861, 862, 863, 864 is in rolling contact with the corresponding inclined surface 821, 822, 823, 824 via the corresponding ball bearing 841, 842, 843, 844. However, the first bearing surface 861 and the third bearing surface 863 will be located below the corresponding inclined surface 821, 823 (relative to the first direction z), while the second bearing surface 862 and the fourth bearing surface 864 will be located above the corresponding inclined surface 822, 824.

[0254] The ring 81 is fixed to the lens holder 80 , for example, by welding, adhesive or other suitable attachment methods. The upper surface (relative to the first direction z) of the lens holder 80 is fixed to the third portion 43 .

[0255] In use, when a first drive device 42 in the form of a first four SMA wire actuator 76 and / or a second drive device 45 in the form of a second four SMA wire actuator 77 applies a torque about an axis parallel to the first direction z, relative rotation between the second portion 40 and the third portion 43 causes the ball bearings 841, 842, 843, 844 to roll between the ramps 821, 822, 823, 824 and the bearing surfaces 861, 862, 863, 864, displacing the lens holder 80 upward or downward (relative to the first direction z) depending on the direction of the torque and the corresponding rotation Rz. While the second portion 40 is maintained in bearing contact with the first portion 39 by the arm 52, the third portion 43 and the attached lens holder 80 move toward or away from the extension plate 78.

[0256] In addition to facilitating upward or downward movement of the lens holder 80, the under-over-under-over configuration of the ramps 821, 822, 823, 824 and the support surfaces 861, 862, 863, 864 means that when the actuator assembly is assembled, the ramps 821, 822, 823, 824 bend to provide a loading force that biases the lens holder 80 toward an equilibrium position along the optical axis 46 (parallel to the first direction z).

[0257] In addition to the movement along the optical axis 46 (parallel to the first direction z), the first actuator 76 and the second actuator 77 can be actuated additionally or alternatively to displace the second part 40 and the third part 43 perpendicular to the first direction. This will displace the axis of rotation of the spiral roller bearing 79 from the optical axis 46, however these axes will remain parallel to the first direction z. This lateral displacement of the lens holder 80 can be controlled (within the range of motion) independently of the rotation to control the travel of the lens holder 80 along the optical axis 46 (parallel to the first direction z), and the two movements can be combined.

[0258] The extension plate 78 is not intended to support or constrain the movement of the third portion 43, but is primarily intended to support the static crimp 54 above the third portion 43 (relative to the first direction z). Therefore, the extension plate 78 connected via the cover 64 can be replaced with any other structure for supporting the static crimp 54 above the third portion 43 (relative to the first direction z). For example, the extension plate 78 can alternatively be provided as an integral extension of the first portion 39, which is folded back on itself. Alternatively, the extension plate 78 can be omitted and the static crimp 55 of the second four SAM wire actuator 77 can be supported on the wall 57 as the first actuator assembly 38 (essentially the first actuator assembly 38, in which the spiral flexure bearing is replaced with a spiral roller bearing).

[0259] Revise

[0260] It will be appreciated that many other variations of the embodiments described above are possible.

[0261] For example, instead of (or possibly in addition to) a lens assembly, an image sensor may be mounted on the third movable part.

[0262] More generally, the actuator assembly may be suitable for moving any component of any device.

[0263] Different SMA driver assemblies and different supports may be suitably used in the actuator assemblies described above.

[0264] In the foregoing description, a portion is described as a rectangle, which should be interpreted as including a square shape. In the foregoing description, a portion is described as a circle, which should be interpreted as including an elliptical shape.

[0265] The first to fourth SMA wires have been described and shown as directly connecting the first portion and the second portion and / or the first portion and the third portion. However, in some examples, the first to fourth SMA wires may indirectly connect the first portion and the second / third portion, for example, via one or more intermediate structures (not shown). The intermediate structures (not shown) may be configured to help extend the travel of one or more SMA wires.

[0266] The first actuator assembly 38 and the second actuator assembly 65 include a second bearing device 44 in the form of a helical flexure bearing, and the third actuator 75 includes a second bearing device 44 in the form of a helical roller bearing. Alternatively, any of the first to third actuator assemblies 38, 65, 75 may be modified to use a similar method to that described with respect to Fig. 7A and Figure 7B The second bearing device 44 in the form of a screw sliding bearing of the screw sliding bearing 29 is described.

[0267] The first to third actuator assemblies 38, 65, 75 have been described as comprising a first support means 41 (such as a first support means 41) in the form of a planar (eg three-point) sliding support. Figure 5A and Figure 5B However, any of the actuator assemblies 38, 65, 75 may be modified to replace the first bearing means 41 with a planar roller bearing or an equivalent planar bearing.

[0268] Four-wire actuator assembly

[0269] The first to third actuator assemblies 38, 65, 75 and variations thereof all use pairs of four SMA wire actuators to provide lateral displacement (perpendicular) and / or rotation relative to the optical axis 46 (parallel to the first direction z), which is converted into translation along (parallel to) the optical axis 46 by the second support device 44. When used as the SMA actuator assembly 2 of the camera 1, the lateral displacement can provide OIS functionality, while the translation along the optical axis 46 provides autofocus or zoom functionality.

[0270] However, in some applications only a translation parallel to the optical axis (principal axis) 46 (ie a translation parallel to the first direction z) may be required. For example, a camera 1 comprising an autofocus or zoom function and omitting OIS or using a separate actuator for OIS.

[0271] The constraint of displacement perpendicular to the optical axis (principal axis) 46 (parallel to the first direction z) of the actuator assembly 38, 65, 75 can be achieved by using a rotating support (e.g. Fig. 8A and Figure 8B The rotating support 34 shown in FIG. 4 is replaced by the first support means 41. Alternatively, any other support that allows rotation around the optical axis 46 while resisting (or even preventing) displacement perpendicular to the optical axis 46 may be used.

[0272] With this additional constraint, eight SMA wires are not required, and the first drive device 42 and the second drive device 45 can be simplified by using two SMA wire actuators instead of four SMA wire actuators. All that is required is one SMA wire that applies torque in a clockwise direction around the optical axis (principal axis) 46 (parallel to the first direction z), and an opposing SMA wire that applies torque in a counterclockwise direction around the optical axis 46. This can be accomplished by simply omitting two SMA wires from each of the first drive device 42 and the second drive device 45.

[0273] Alternatively, also refer to Fig.16 , a first dual SMA wire actuator 87 is shown.

[0274] The first dual SMA wire actuator 87 includes a first structure 88 and a second structure 89 coupled by a rotating bearing (not shown). A pair of pillars 901, 902 stand upright from two corners along a single side of the first structure 88. A first SMA wire 911 connects the upper right corner (as shown) of the second structure to the first pillar 901 disposed in the upper left corner (as shown) of the first structure 88. A second SMA wire 912 connects the lower right corner (as shown) of the second structure to the second pillar 902 disposed in the lower left corner (as shown) of the first structure 88.

[0275] When the first SMA wire 911 contracts, a torque is applied counterclockwise on the second structure 89. When the second SMA wire 912 contracts, a torque is applied counterclockwise on the second structure 89. Both torques are unbalanced and in either case also apply a force in the -x direction as shown. However, the lateral force is resisted by the constraint of the rotating bearing (not shown) coupling the first structure 88 and the second structure 89.

[0276] Two upper, two lower, four SMA wire actuator assemblies can be formed by connecting a spiral support between a pair of first dual SMA wire actuators 87 so that the rotation generated by the applied torque can be converted into a translation parallel to the optical axis (main axis) 46 (as shown, parallel to the first direction z).

[0277] Also refer to Fig.17 , a second dual SMA wire actuator 92 is shown.

[0278] The second dual SMA wire actuator 92 is identical to the first dual SMA wire actuator 87 except that the second leg 902 is omitted, and a second SMA wire 912 connects the lower left corner of the second structure (as shown) to the first leg 901 .

[0279] Dual-wire actuator assembly

[0280] Even further simplification is possible if one of the SMA wires 911, 912 of the dual SMA wire actuator 87, 92 is replaced by a spring. In such an example, torque in one direction (clockwise or counterclockwise) is provided by contraction of the SMA wire opposed by the spring rather than the opposing SMA wire. Torque is applied in the opposite direction by stopping driving the SMA wire to allow it to cool and expand under the drive of the spring.

[0281] Although an example has been described in which the respective first directions are aligned parallel to the z-axis of the Cartesian coordinate system, this is purely for clarity of explanation.

[0282] The above-mentioned SMA actuator assembly includes an SMA wire. The term "shape memory alloy (SMA) wire" may refer to any element containing SMA. The SMA wire may have any shape suitable for the purposes described herein. The SMA wire may be elongated and may have a rounded 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 (regardless of how it is defined) may also be similar to one or more of its other dimensions. The SMA wire may be compliant, or in other words, flexible. In some examples, when connected in a straight line between two elements, the SMA wire can only apply a pulling force that pushes the two elements together. In other examples, the SMA wire can be bent around the element, and when the SMA wire tends to straighten under tension, a force can be applied to the element. The SMA wire may be beam-shaped or rigid and can apply different (e.g., non-tensile) forces to the element. The SMA wire may or may not include non-SMA materials and / or components. For example, the SMA wire may include an SMA core and a coating of a non-SMA material. Unless the context requires otherwise, the term "SMA wire" may refer to any configuration of an SMA wire that acts as a single actuation element, e.g., an actuation element that can be individually controlled to generate a force on the element. For example, an SMA wire may include two or more SMA wire portions that are mechanically arranged in parallel and / or in series. In some arrangements, an SMA wire may be part of a larger length of SMA wire. The larger length of SMA wire may include two or more portions that are individually controllable, thereby forming two or more SMA wires.

Claims

1. An actuator assembly, comprising: Part I; Part II; a first support means mechanically coupling the first portion to the second portion; A first driving device, the first driving device comprising four sections of shape memory alloy wire; wherein the first supporting device and the first driving device are configured to enable the second part to rotate relative to the first part around an axis parallel to the first direction; Part III; a second support means mechanically coupling the second portion to the third portion; and a second driving device, the second driving device comprising four sections of shape memory alloy wire; Wherein, the second supporting device, the first driving device and the second driving device are configured so that in response to a torque applied by the first driving device and / or the second driving device around an axis parallel to the first direction, the third part moves toward or away from the first part along the first direction.

2. The actuator assembly of claim 1, wherein: The first support device and the first drive device are configured to enable the second part to move perpendicularly to the first direction relative to the first part; and The second supporting device and the second driving device are configured to enable the third part to move relative to the first part perpendicular to the first direction.

3. The actuator assembly of claim 2, the actuator assembly being configured to enable the second portion and the third portion to move perpendicularly to the first direction relative to the first portion while maintaining a position of the third portion relative to the second portion.

4. The actuator assembly of claim 2, wherein the actuator assembly is configured to enable the second portion and the third portion to move differently perpendicular to the first direction so as to tilt the third portion relative to the first portion and the second portion about an axis perpendicular to the first direction.

5. The actuator assembly according to claim 1, wherein: The first support device is configured to resist movement of the second portion along the first direction toward or away from the first portion.

6. The actuator assembly according to claim 1, wherein: The first support means is configured to allow the second part to move relative to the first part in a plane perpendicular to the first direction.

7. The actuator assembly of claim 1, wherein: The first supporting device comprises: Plane support.

8. The actuator assembly of claim 1, wherein: The four sections of shape memory alloy wire in the first driving device are substantially coplanar.

9. An actuator assembly according to any one of claims 1 to 8, wherein: The four sections of shape memory alloy wire in the second driving device are substantially coplanar.

10. An actuator assembly according to any one of claims 1 to 8, wherein: The four lengths of shape memory alloy wire in the first drive device are substantially coplanar in a first plane; and The four sections of shape memory alloy wire in the second driving device are substantially coplanarly located in a second plane; Wherein, the first plane and the second plane are parallel.

11. The actuator assembly of claim 10, wherein: The first plane and the second plane are offset from each other along the first direction.

12. The actuator assembly of claim 10, wherein: The first plane and the second plane are substantially coplanar.

13. An actuator assembly according to any one of claims 1 to 8, wherein: The four segments of shape memory alloy wire in the first drive device span a first length parallel to the first direction, the four segments of shape memory alloy wire in the second drive device span a second length parallel to the first direction, and the first length and the second length at least partially overlap.

14. The actuator assembly of claim 13, wherein: The four sections of shape memory alloy wire in the first driving device and the four sections of shape memory alloy wire in the second driving device are each connected to the first section via a connecting portion, and the connecting portion is located in a plane perpendicular to the first direction.

15. The actuator assembly of claim 14, comprising four shape memory alloy wires, each shape memory alloy wire providing one of the four segments of shape memory alloy in the first drive device and one of the four segments of shape memory alloy in the second drive device, wherein each shape memory alloy wire is connected to the first portion via a common connecting portion at or near a midpoint of the shape memory alloy wire.

16. The actuator assembly according to any one of claims 1-8, 11-12 and 14-15, wherein: The second support means comprises a helical support.

17. An actuator assembly according to any one of claims 1-8, 11-12 and 14-15, wherein: The second bearing means comprises a helical rolling element bearing.

18. The actuator assembly of claim 17, wherein: The spiral rolling element support comprises: A plurality of helical support portions are arranged in a ring about an axis parallel to the first direction.

19. The actuator assembly of claim 18, wherein: Each spiral bearing section comprises: A first bearing surface, a second bearing surface and at least one rolling element, the at least one rolling element being arranged to be guided along a helical path by the first bearing surface and the second bearing surface.

20. The actuator assembly of claim 18, wherein: Each spiral bearing section comprises: A flexible ramp, wherein the flexible ramp is prestressed in an equilibrium or neutral configuration of the first support.

21. An actuator assembly according to any one of claims 1-8, 11-12 and 14-15, wherein: The second support means comprises a helical flexure.

22. The actuator assembly of claim 21, wherein: The helical flexure includes at least three flexure arms extending in a direction parallel to the first direction and in the same orientation around an axis parallel to the first direction.

23. The actuator assembly of claim 21, further comprising: An annular ring is connected to the third portion and interposed between the third portion and the second portion.

24. The actuator assembly of any one of claims 1-8, 11-12, 14-15, 18-20, and 22-23, wherein: The second portion includes a first annular member; The first annular member is substantially coplanar with the third portion at a position where the third portion is closest to the second portion along the first direction.

25. The actuator assembly of claim 24, wherein: The second portion includes a first pair of arms extending radially away from the first annular member; and The third portion includes a second pair of arms extending radially away from an axis parallel to the first direction.

26. The actuator assembly of claim 17, wherein: The spiral rolling element support comprises: a first piece, the first piece having a plurality of first guide sections in the first piece; a second member having a plurality of second guide sections, each second guide section facing the first guide section; and a plurality of ball bearing elements, wherein each ball bearing element is located in a first guide section and a second guide section between the first member and the second member; Wherein, the first guide section and the second guide section are tapered so that relative rotation of the first member and the second member in a first direction causes each ball bearing element to roll toward the narrower end of each guide section, thereby moving the first member and the second member away from each other, and relative rotation of the first member and the second member in an opposite second direction causes each ball bearing element to roll toward the wider end of each guide section, thereby moving the first member and the second member toward each other.

27. The actuator assembly of claim 26, wherein: The first piece and the second piece are sheets of material, and the first guide section and the second guide section are holes in the sheets of material.

28. A camera module comprising: An actuator assembly according to any one of claims 1 to 25; an image sensor supported by one of the first portion and the third portion; A lens is supported by the other of the first portion and the third portion.

29. The camera module of claim 28, further comprising: A controller is configured to use movement of the third portion along the first direction toward or away from the second portion to control the actuator assembly to implement an autofocus function.

30. An actuator assembly comprising: Part I; Part II; a first support means mechanically coupling the first portion to the second portion; a first actuation device, the first actuation device comprising one or more lengths of shape memory alloy wire; wherein the first supporting device and the first driving device are configured to enable the second part to rotate relative to the first part around an axis parallel to the first direction; Part III; a second support means mechanically coupling the second portion to the third portion; and a second actuation device, the second actuation device comprising one or more lengths of shape memory alloy wire; Wherein, the second supporting device, the first driving device and the second driving device are configured so that in response to a torque applied by the first driving device and / or the second driving device around an axis parallel to the first direction, the third part moves toward or away from the first part along the first direction.

31. The actuator assembly of claim 30, wherein: The first driving device includes a first section of shape memory alloy wire and a second section of shape memory alloy wire, wherein the first section of shape memory alloy wire is configured to apply torque clockwise around an axis parallel to the first direction, and the second section of shape memory alloy wire is configured to apply torque counterclockwise around the axis parallel to the first direction.

32. The actuator assembly of claim 31, wherein: The second driving device includes a third section of shape memory alloy wire and a fourth section of shape memory alloy wire, the third section of shape memory alloy wire is configured to apply torque clockwise around an axis parallel to the first direction, and the fourth section of shape memory alloy wire is configured to apply torque counterclockwise around the axis parallel to the first direction.

33. The actuator assembly of any one of claims 30 to 32, further comprising one or more first springs coupling the first portion to the second portion, each first spring being configured to oppose contraction of at least a length of shape memory alloy wire of the first drive means.

34. An actuator assembly according to any one of claims 30 to 32, further comprising one or more second springs coupling the first portion to the third portion, each second spring being configured to oppose contraction of at least a length of shape memory alloy wire of the second drive means.

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