WO2023111547A1 - Appareil d'actionnement par amf - Google Patents

Appareil d'actionnement par amf Download PDF

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Publication number
WO2023111547A1
WO2023111547A1 PCT/GB2022/053211 GB2022053211W WO2023111547A1 WO 2023111547 A1 WO2023111547 A1 WO 2023111547A1 GB 2022053211 W GB2022053211 W GB 2022053211W WO 2023111547 A1 WO2023111547 A1 WO 2023111547A1
Authority
WO
WIPO (PCT)
Prior art keywords
movable part
gimbal
support structure
sma
axis
Prior art date
Application number
PCT/GB2022/053211
Other languages
English (en)
Inventor
James Howarth
Andrew Benjamin Simpson Brown
Original Assignee
Cambridge Mechatronics Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Cambridge Mechatronics Limited filed Critical Cambridge Mechatronics Limited
Publication of WO2023111547A1 publication Critical patent/WO2023111547A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
    • H04N23/60—Control of cameras or camera modules
    • H04N23/68—Control of cameras or camera modules for stable pick-up of the scene, e.g. compensating for camera body vibrations
    • H04N23/682—Vibration or motion blur correction
    • H04N23/685—Vibration or motion blur correction performed by mechanical compensation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03G—SPRING, WEIGHT, INERTIA OR LIKE MOTORS; MECHANICAL-POWER PRODUCING DEVICES OR MECHANISMS, NOT OTHERWISE PROVIDED FOR OR USING ENERGY SOURCES NOT OTHERWISE PROVIDED FOR
    • F03G7/00—Mechanical-power-producing mechanisms, not otherwise provided for or using energy sources not otherwise provided for
    • F03G7/06—Mechanical-power-producing mechanisms, not otherwise provided for or using energy sources not otherwise provided for using expansion or contraction of bodies due to heating, cooling, moistening, drying or the like
    • F03G7/061—Mechanical-power-producing mechanisms, not otherwise provided for or using energy sources not otherwise provided for using expansion or contraction of bodies due to heating, cooling, moistening, drying or the like characterised by the actuating element
    • F03G7/0614—Mechanical-power-producing mechanisms, not otherwise provided for or using energy sources not otherwise provided for using expansion or contraction of bodies due to heating, cooling, moistening, drying or the like characterised by the actuating element using shape memory elements
    • F03G7/06143—Wires
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03G—SPRING, WEIGHT, INERTIA OR LIKE MOTORS; MECHANICAL-POWER PRODUCING DEVICES OR MECHANISMS, NOT OTHERWISE PROVIDED FOR OR USING ENERGY SOURCES NOT OTHERWISE PROVIDED FOR
    • F03G7/00—Mechanical-power-producing mechanisms, not otherwise provided for or using energy sources not otherwise provided for
    • F03G7/06—Mechanical-power-producing mechanisms, not otherwise provided for or using energy sources not otherwise provided for using expansion or contraction of bodies due to heating, cooling, moistening, drying or the like
    • F03G7/066—Actuator control or monitoring
    • F03G7/0665—Actuator control or monitoring controlled displacement, e.g. by using a lens positioning actuator
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
    • H04N23/50—Constructional details
    • H04N23/54—Mounting of pick-up tubes, electronic image sensors, deviation or focusing coils
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
    • H04N23/50—Constructional details
    • H04N23/55—Optical parts specially adapted for electronic image sensors; Mounting thereof
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
    • H04N23/60—Control of cameras or camera modules
    • H04N23/68—Control of cameras or camera modules for stable pick-up of the scene, e.g. compensating for camera body vibrations
    • H04N23/682—Vibration or motion blur correction
    • H04N23/685—Vibration or motion blur correction performed by mechanical compensation
    • H04N23/687—Vibration or motion blur correction performed by mechanical compensation by shifting the lens or sensor position
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B2205/00—Adjustment of optical system relative to image or object surface other than for focusing
    • G03B2205/0053—Driving means for the movement of one or more optical element
    • G03B2205/0076—Driving means for the movement of one or more optical element using shape memory alloys

Definitions

  • the present application relates to an actuation apparatus, particularly an actuation apparatus comprising a plurality of lengths of shape-memory alloy (SMA) wire configured to tilt a movable part relative to a support structure about at least one tilt axis which is perpendicular to the primary axis of the actuation apparatus.
  • SMA shape-memory alloy
  • Such an actuation apparatus may be used, for example, in a camera to tilt a camera module, comprising an image sensor and a lens element arranged to focus an image on the image sensor, relative to a support structure so as to provide optical image stabilization (OIS).
  • OIS optical image stabilization
  • Such an actuation apparatus may also be used, for example, in a 3D sensing system or in an augmented reality (AR) display system to tilt an emitter, a display, or a part thereof.
  • AR augmented reality
  • WO 2011/104518 Al discloses an SMA actuation apparatus that uses SMA actuator wires to move a movable element (for example, a camera module comprising an image sensor and a lens assembly) relative to a support structure to provide, for example, OIS by tilting the movable element relative to the support structure.
  • a movable element for example, a camera module comprising an image sensor and a lens assembly
  • an SMA actuation apparatus comprising: a movable part; a support structure; a plurality of SMA wires arranged, on contraction, to tilt the movable part relative to the support structure about at least one tilt axis that is perpendicular to a primary axis of the SMA actuation apparatus; and a gimbal pivoted to one of the movable part and the support structure such that the gimbal is configured to tilt relative to said one of the movable part and the support structure; wherein the gimbal is configured such that movement of the movable part relative to the support structure parallel to the primary axis is stopped by engagement between the gimbal and the other of the movable part and the support structure.
  • the gimbal functions as a rotationally constrained end stop for the direction parallel to the primary axis.
  • the gimbal functions as the end stop without inhibiting the movable part e.g. from tilting about the at least one tilt axis.
  • the gimbal reduces the possibility of damage of the movable part, particularly during shock and/or drop events e.g. wherein a device (e.g. a smartphone) comprising the actuation apparatus is dropped onto a hard surface.
  • the primary axis may pass through the movable part.
  • the primary axis may be defined with reference to the support structure.
  • the primary axis may be a longitudinal axis of the SMA actuation apparatus.
  • the primary axis may be a longitudinal axis of the support structure.
  • the at least one tilt axis comprises a first axis and a second axis which are perpendicular to each other (and perpendicular to the primary axis); and the movable part and the gimbal are engaged such that the gimbal is configured to tilt (with the movable part) relative to the support structure when the movable part is tilted about the first axis, and the movable part is configured to tilt relative to the gimbal when the movable part is tilted about the second axis.
  • the movable part and the gimbal are engaged such that tilting of the movable part about the first axis causes the gimbal to tilt relative to the support structure, and such that tilting of the movable part about the second axis allows the movable part to tilt relative to the gimbal.
  • the axis about which the gimbal is configured to tilt, when the movable part is tilted about the first axis, is parallel to the first axis and spaced from the first axis.
  • the plurality of SMA wires are configured to be capable of translationally moving the movable part relative to the support structure perpendicular to the primary axis.
  • the plurality of SMA wires are arranged, on contraction, to translationally move the movable part relative to the support structure perpendicular to the primary axis.
  • the gimbal is configured such that the other of the movable part and the support structure can translationally move relative to the gimbal perpendicular to the primary axis.
  • the movable part comprises an electronic component comprising a radiation-sensing (e.g. light-sensing) or radiation-emitting (e.g. light-emitting) side which faces towards a first direction; and wherein the gimbal is configured such that movement of the movable part relative to the support structure in the first direction is stopped by engagement between the gimbal and the other of the movable part and the support structure.
  • the electronic component may be an image sensor, a display, an emitter, or a part thereof.
  • the gimbal is configured to engage with said one of the movable part and the support structure at two locations such that the gimbal is configured to tilt relative to said one of the movable part and the support structure about an axis defined between the two locations.
  • the gimbal extends along each of four sides around the primary axis.
  • a drop event e.g. wherein a device (e.g. a smartphone) comprising the actuation apparatus is dropped onto a hard surface
  • the movable part may contact the gimbal and the gimbal will transfer this force through to the support structure.
  • the gimbal extends beyond the support structure parallel to the primary axis.
  • the gimbal is pivoted to said one of the movable part and the support structure at a pivot having a fixed location relative to said one of the movable part and the support structure parallel to the primary axis.
  • the gimbal is formed from sheet metal.
  • the gimbal is pivoted to said one of the movable part and the support structure via a flexure.
  • the gimbal may be formed by bending sheet metal.
  • the gimbal is fixed to said one of the movable part and the support structure so as to prevent translational movement of the gimbal relative to said one of the movable part and the support structure perpendicular to the primary axis.
  • the movable part is a camera unit (herein also referred to as camera module) comprising an image sensor and a camera lens element arranged to focus an image on the image sensor.
  • camera module a camera unit comprising an image sensor and a camera lens element arranged to focus an image on the image sensor.
  • the plurality of SMA wires comprises eight SMA wires inclined with respect to the primary axis with two SMA actuator wires on each of four sides around the primary axis.
  • the two SMA actuator wires are inclined in opposite senses with respect to each other and cross.
  • the SMA actuation apparatus comprises a flexible electrical connector connected between the movable part and the support structure.
  • the flexible connector may be for making electrical connections to the above-mentioned electronic component.
  • the movable part is supported on the support structure solely by the SMA wires.
  • the movable part may be configured to be suspended relative to the support structure solely by the plurality of SMA wires.
  • An embodiment of the invention is an actuation apparatus having a movable part which is controlled by the wire suspension and is not mechanically constrained by bearings. This lack of constraint allows the SMA wires to drive the movable part to large tilt angles whilst allowing the flexing of the flexible electrical connector attached to the movable part.
  • Figure 1 is a schematic diagram of an SMA actuation apparatus
  • Figure 2 schematically illustrates possible degrees of freedom which may be provided by an SMA actuator
  • Figure 3 is a schematic diagram of a component connected to a movable part of an SMA actuation apparatus
  • Figure 4 is a schematic diagram of an SMA actuator
  • Figure 5 is a schematic side on view of an SMA actuation apparatus
  • Figure 6 is a schematic top down view of the SMA actuation apparatus shown in Figure 5;
  • Figure 7 is a schematic perspective view of an SMA actuation apparatus
  • Figure 8 is a schematic perspective view of part of an SMA actuation apparatus
  • Figure 9 is a schematic side on view of the SMA actuation apparatus shown in Figure 8.
  • Figure 10 is a schematic perspective view of a gimbal
  • Figure 11 is a schematic side on view of the gimbal shown in Figure 10;
  • Figure 12 is a schematic perspective view of part of an SMA actuation apparatus; and Figure 13 is a schematic side on view of the SMA actuation apparatus shown in Figure 12.
  • FIG. 1 is a schematic diagram of a SMA actuation apparatus 1.
  • the SMA actuation apparatus 1 includes a movable part 81 (herein also referred to as movable element 81) and a support structure 82.
  • the support structure 82 includes a base 5.
  • the movable part 81 may be a camera module 81 comprising a lens assembly 4 and an image sensor 6.
  • the movable part 81 may be suspended on the support structure 82 by a SMA actuator 2 comprising a plurality of SMA wires (herein also referred to as SMA actuator wires).
  • the image sensor 6 is disposed in front of a front side of the base 5, i.e., the image sensor 6 is interposed between the lens assembly 4 and the base 5.
  • the lens assembly 4 is positioned above the image sensor 6 with respect to a primary axis P of the camera assembly 1.
  • the primary axis P is defined with reference to the support structure 82.
  • the primary axis P may be perpendicular to the major surfaces of the base 5 and may pass through the centre of the support structure 82, the centre of an aperture of a can 8 of the support structure 82, and/or the centre of the SMA actuation apparatus 1.
  • the primary axis P may be a longitudinal axis of the SMA actuation apparatus 1 and/or the support structure 82.
  • the SMA actuator 2 supports the movable part 81 in a manner allowing one or more degrees-of- freedom of the movable part 81 relative to the support structure 82.
  • the lens assembly 4 has an optical axis O. As shown in Fig. 1, the optical axis O is aligned with the primary axis P when the movable part 81 is in its neutral position in which the image sensor 6 is substantially parallel to the base 5 (i.e. when the movable part 81 is in the untilted position with respect to the support structure 82) and the movable part 81 is laterally centred between the SMA actuator assembly 2.
  • the SMA actuation apparatus 1 includes an integrated circuit (IC) 7, which implements a control circuit, and also a gyroscope sensor (not shown).
  • the support structure 82 also includes a can 8 which protrudes forwardly from the base 5 to encase and protect the other components of the SMA actuation apparatus 1.
  • the lens assembly 4 includes a lens carriage 9 in the form of a cylindrical body supporting two lenses 10 arranged along the optical axis O. In general, any number of one or more lenses 10 may be included.
  • the SMA actuation apparatus 1 may be comprised in a camera, which may be referred to as a miniature camera.
  • the lens assembly 4 is arranged to focus an image onto the image sensor 6.
  • the image sensor 6 captures the image and may be of any suitable type, for example, a charge-coupled device (CCD) or a complementary metal-oxide- semiconductor (CMOS) device.
  • CCD charge-coupled device
  • CMOS complementary metal-oxide- semiconductor
  • the lens carriage 9 may include an actuator assembly (not shown) configured to move at least one of the lenses 10 along the optical axis O relative to the image sensor 6, for example to provide autofocussing (AF) or zoom.
  • an actuator is also referred to as an AF actuator and may be an SMA actuator comprising SMA wires, a voice coil motor (VCM) actuator, or any other suitable type of actuator.
  • the plurality of SMA wires are arranged, on contraction, to tilt/rotate the movable part 81 relative to the support structure 82 about two orthogonal axes that are perpendicular about the primary axis P of the SMA actuation apparatus 1.
  • the SMA wires are arranged, on contraction, to tilt the movable part 81 relative to the support structure 82 about axes parallel to the x and y axes.
  • the actuation apparatus 1 comprises a plurality of SMA wires configured to tilt the movable part 81 relative to the support structure 82 about at least one tilt axis that is perpendicular to a primary axis P, wherein the at least one tilt axis may comprise a first axis (herein also referred to as a first tilt axis) and a second axis (herein also referred to as a second tilt axis) which are perpendicular to each other and perpendicular to the primary axis.
  • a first tilt axis herein also referred to as a first tilt axis
  • a second tilt axis herein also referred to as a second tilt axis
  • OIS functionality may be provided by tilting the movable part 81 (i.e. the lens assembly 4 and the image sensor 6) about the first tilt axis and/or about the second tilt axis. Additionally, as discussed above, the lens assembly 4, or at least one lens 10 thereof, may be moved parallel to the optical axis O (parallel to the third axis z) to provide focussing of an image formed on the image sensor 6, for example as part of an automatic focussing (AF) function.
  • AF automatic focussing
  • This specification mainly provides examples of SMA actuation apparatuses 1 which provide OIS that is based on tilting the movable part 81 (i.e. the lens assembly 4 and the image sensor 6) relative to the support structure 82.
  • AF may be provided by an additional system which may or may not use SMA wires.
  • a first degree-of-freedom (DOF) Tx corresponds to movement parallel to the x-axis x.
  • a second DOF Ty corresponds to movement parallel to the y-axis y.
  • a third DOF Tz corresponds to movement parallel to the z-axis z, which is aligned with the primary axis P.
  • the third DOF Tz corresponds to movement of the lens assembly 4 and the image sensor 6 towards or away from the base 5.
  • the x-, y- and z-axes x, y, z form a right-handed Cartesian coordinate system.
  • a fourth DOF Rx corresponds to rotation about an axis parallel to the x-axis x.
  • a fifth DOF Ry corresponds to rotation about an axis parallel to the y-axis y.
  • a sixth DOF Rz corresponds to rotation about an axis parallel to the z-axis z.
  • Motions of the movable part 81 relative to the support structure 82 may be broken down into components of any or all of the first to sixth DOF (movements) Tx, Ty, Tz, Rx, Ry, Rz.
  • This specification concerns SMA actuation apparatuses 1 which provide the motions corresponding to at least one of the fourth and fifth DOF Rx, Ry.
  • the fourth and fifth DOF Rx, Ry provide the OIS functionality herein.
  • the plurality of SMA wires of the SMA actuator 2 are arranged, on contraction, to tilt the movable part 81 relative to the support structure 82 about at least one tilt axis that is perpendicular to a primary axis P of the SMA actuation apparatus 1.
  • the at least one tilt axis may pass through the movable part 81.
  • the plurality of SMA wires of the SMA actuator 2 may also be configured to be capable of translationally moving the movable part 81 relative to the support structure 82 perpendicular to the primary axis P.
  • the actuation apparatus 1 may comprise a flexible electrical connector 90 that is connected to the movable part 81.
  • the flexible electrical connector 90 may be connected between the movable part 81 and the support structure 82.
  • the flexible electrical connector 90 may be configured to provide an electrical connection from the movable part 81 to the support structure 82 or an external component.
  • the electrical connection may be for transferring control signals and/or image data.
  • the flexible electrical connector 90 may be a flexible circuit board.
  • the SMA actuator 2 comprises the eight SMA wire arrangement 80 shown in Fig. 4 and described in WO 2011/104518 Al which is incorporated herein by reference.
  • the arrangement 80 shown in Figure 4 includes SMA actuator wires 71-78 arranged on each of four perpendicular sides of the primary axis P and coupled to the movable element 81 and the support structure 82. As shown in Figures 5, 6, 9 and 13 each of the SMA wires 71-78 may be coupled at one end to the movable part 81 via moving crimps 41 and coupled at the other end to the support structure 82 via support crimps 42. Two of the SMA wires 71-78 are arranged on each of four sides around the primary axis P. The two SMA wires on each side are inclined in opposite senses with respect to each other, as viewed perpendicular from the primary axis P, and cross each other.
  • the four sides on which the SMA wires 71-78 are arranged extend in a loop around the primary axis P.
  • the sides are perpendicular and so form a square as viewed along the primary axis P, but alternatively the sides could take a different quadrilateral shape.
  • the SMA wires 71-78 may be parallel to the outer faces of the movable part 81 which conveniently packages the SMA actuation apparatus 1.
  • the actuation apparatus 1 comprises a control circuit electrically connected to the SMA wires 71-78 for supplying drive signals/drive currents to the SMA wires. The forces exerted by the SMA wires 71-78 are controlled by selectively varying the temperatures of the SMA wires 71-78.
  • one of the SMA actuator wires 71-78 on each side provides a force on the movable element 81 in the same direction along the primary axis P.
  • the SMA actuator wires 71, 73, 75, 77 form a group that provide a force in one direction (upwards in Figure 3) and the other SMA actuator wires 72, 74, 76, 78 form a group that provide a force in the opposite direction (downwards in Figure 3).
  • the SMA actuator wires 71-78 have a symmetrical arrangement in which lengths and inclination angles are the same, so that both the group of SMA actuator wires 71, 73, 75, 77 and the group of SMA actuator wires 72, 74, 76, 78 are each arranged with two-fold rotational symmetry about the primary axis P (i.e. bisecting the angle between SMA actuator wires 71-78 on adjacent sides and across the diagonals of the square shape of the movable element).
  • the SMA wires 71-78 are arranged, on contraction, to tilt the movable element 81 relative to the support structure 82 about two orthogonal axes, perpendicular to the primary axis P.
  • the group of SMA actuator wires 71, 73, 75, 77 and the group of SMA actuator wires 72, 74, 76, 78 when commonly actuated drive movement along the primary axis P.
  • adjacent pairs of the SMA actuator wires when differentially actuated drive tilting about a lateral axis perpendicular to the primary axis P. Tilting in any arbitrary direction may be achieved as a linear combination of tilts about the two lateral axes.
  • Sets of four SMA actuator wires including two SMA actuator wires from each group, (for example on one hand SMA actuator wires 71, 72, 77, 78 and on the other hand SMA actuator wires 73-76) when commonly actuated drive movement along a lateral axis perpendicular to the primary axis P. Movement in any arbitrary direction perpendicular to the primary axis P may be achieved as a linear combination of movements along the two lateral axes.
  • the SMA wire 71-78 shown in Figure 4 are arranged, on selective contraction, to tilt the movable part 81 relative to the support structure 82 about at least one axis, and preferably two orthogonal axes, perpendicular to the primary axis P of the SMA actuation apparatus 1.
  • the primary axis P is perpendicular to the major surfaces of the movable part 81 (e.g. the light-sensitive surface of the image sensor 6) when the movable part 81 is in its neutral or untilted position with respect to the support structure 3.
  • the actuation apparatus 1 described above has a movable part 81 which may be supported on the support structure 82 solely by the SMA wires 71-78 and may not be mechanically constrained by bearings.
  • This lack of constraint allows the SMA wires 71-78 to drive the movable part 81 to large tilt angles.
  • this lack of constraint also means that the movable part 81 is more likely to sustain damage from drops, e.g. wherein a device (e.g. a smartphone) comprising the actuation apparatus 1 is dropped onto a hard surface, as the movable part 81 can move relatively large distances in the z- direction.
  • a gimbal 20 which functions as a rotationally constrained z-direction end stop may be provided to help with this issue.
  • Figures 5 to 13 show examples of such gimbals 20.
  • the gimbal 20 is provided between the movable part 81 and the support structure 82.
  • the gimbal 20 is in direct engagement with both the support structure 82 and the movable part 81.
  • the engagement between the gimbal 20 and the movable part 81 is such that, when the movable part 81 is tilted about the first (tilt) axis relative to the support structure 82, the gimbal 20 is configured to tilt with the movable part 81 relative to the support structure 82. Moreover, the gimbal 20 and the movable part 81 are engaged such that when the movable part 81 is tilted about the second (tilt) axis relative to the support structure 82, the movable part 81 is configured to tilt relative to the gimbal 20.
  • the axis about which the gimbal 20 is configured to tilt when the movable part 81 is tilted about the first axis, may be parallel to the first axis and spaced from the first axis.
  • the gimbal 20 when the movable part 81 is tilted about the first axis, the gimbal 20 may be configured to tilt with the movable part 81 relative to the support structure 81 about an axis that is distinct from the first axis.
  • the first axis may be an axis passing underneath the movable part 81, whereas the axis about which the gimbal 20 is configured to tilt about may pass above the movable part 81.
  • the movable part 81 is configured to slide relative to the gimbal 20 in Figures 5 to 13, wherein the gimbal 20 is pivoted to the support structure 82.
  • the gimbal 20 may instead be configured to slide relative to the support structure 82.
  • the gimbal 20 is pivoted to one of the movable part 81 and the support structure 82 such that the gimbal 20 is configured to tilt relative to said one of the movable part 81 and the support structure 82.
  • the gimbal 20 is pivoted to the support structure 82 at two pivot locations 22 such that the gimbal 20 is configured to tilt relative to the support structure 82 about an axis defined between the two pivot locations 22.
  • the gimbal 20 may instead be pivoted to the movable part 81 at two pivot locations such that the gimbal 20 is configured to tilt relative to the movable part 81 about an axis defined between the two pivot locations.
  • the gimbal 20 is pivoted to one of the movable part 81 and the support structure 82 at two (pivot) locations such that the gimbal 20 is configured to tilt relative to said one of the movable part and the support structure about an axis defined between the two (pivot) locations.
  • the gimbal 20 is configured to engage with the movable part 81 at two engagement locations 21 such that the gimbal 20 is configured to tilt relative to the movable part
  • the gimbal 20 may instead be configured to engage with the support structure 82 at two engagement locations such that the gimbal 20 is configured to tilt relative to the support structure 82 about an axis defined between the two engagement locations. As such, it can be said that the gimbal 20 is configured to engage one of the movable part 81 and the support structure
  • the gimbal 20 is configured such that movement of the movable part 81 relative to the support structure 82 parallel to the primary axis P is stopped by engagement between the gimbal 20 and the movable part 81.
  • the gimbal 20 may instead be configured such that movement of the movable part 81 relative to the support structure 82 parallel to the primary axis P is stopped by engagement between the gimbal 20 and the support structure 82.
  • the gimbal 20 is pivoted to one of the movable part 81 and the support structure 82 such that the gimbal 20 is configured to tilt relative to said one of the movable part 81 and the support structure 82, and the gimbal 20 is configured such that movement of the movable part 81 relative to the support structure 82 parallel to the primary axis P is stopped by engagement between the gimbal 20 and the other of the movable part 81 and the support structure 82.
  • the gimbal 20 moves freely to allow tilt rotation of the movable part 81.
  • a corner of the movable part 81 corresponding to where the engagement location 21 is may move in the +z direction (e.g. upwards in the view of Figure 5). In general, this will occur at the same time as the opposite corner of the movable part 81 corresponding to another engagement location 21 moving in the -z direction. This causes the gimbal 20 to tilt together with the movable part 81.
  • a corner of the movable part 81 corresponding to where the pivot location 22 is may move in the +z direction (i.e. upwards in the view of Figure 5). In general, this will occur at the same time as the opposite corner of the movable part 81 corresponding to another pivot location 22 moving in the -z direction. There is a gap 23 between the movable part 81 and the gimbal 20 to allow for this rotation.
  • the gimbal 20 functions as a rotationally constrained end stop for the direction parallel to the primary axis P.
  • the gimbal 20 functions as an end stop without inhibiting tilting of the movable part 81 relative to the support structure 82.
  • the gimbal 20 also functions as an end stop without inhibiting translation of the movable part 81 in directions perpendicular to the primary axis P as the movable part 81 is configured to slide relative to the gimbal 20 wherein the gimbal 20 is pivoted to the support structure 82 (as shown in Figures 5 to 13), or configured to slide relative to the support structure 82 wherein the gimbal 20 is pivoted to the movable part 81 (not shown but discussed above).
  • the gimbal 20 is pivoted to one of the movable part 81 and the support structure 82, and the gimbal 20 is configured such that the other of the movable part 81 and the support structure 82 can translationally move relative to the gimbal 20 perpendicular to the primary axis P.
  • the gimbal 20 reduces the possibility of damage to the movable part 81 during drop events while allowing the movable part 81 to move in such a way that the axis of tilt may be controlled as desired.
  • the movable part 81 comprises an image sensor 6.
  • the light-sensing surface of the image sensor 6 is configured to face towards a first direction (e.g. upwards in Figure 1 or the +z direction) away from the base of the support structure 82.
  • This first direction e.g. +z direction
  • the image sensor 6 may be replaced with any other electronic component such as a display or an emitter.
  • the movable part 81 comprises an electronic component comprising a light-sensing or lightemitting side which faces towards a first direction
  • the gimbal 20 is configured such that movement of the movable part 81 relative to the support structure 82 in the first direction is stopped by engagement between the gimbal 20 and the movable part 81 (wherein the gimbal 20 is pivoted to the support structure 82) and the support structure 82 (wherein the gimbal 20 is pivoted to the movable part 81).
  • the gimbal 20 extends along each of four sides around the primary axis P.
  • the movable part 81 will contact the gimbal 20 and the gimbal 20 will transfer this force through to the support structure 82.
  • Engagement locations 22 may be provided at opposite corners of the gimbal 20.
  • Pivot locations 21 may be provided at the other two opposite corners of the gimbal 20.
  • the gimbal 20 extends beyond the support structure 82 parallel to the primary axis P.
  • Figure 7 shows a variant of Figure 5 where the gimbal 20 is placed over the movable part 81 that is being tilted.
  • the gimbal 20 does not restrict the design of the actuator 2 as it only enters space allocated to the movable part 81 at the two regions where it hooks under the can 8.
  • the gimbal 20 is very simple: just a formed sheet of metal.
  • the movable part 81 may be configured to tilt around axes near the bottom of the movable part 81 (e.g. near the flexible electrical connector 90).
  • the gimbal 20 comprises sloped sections 24 configured to form a gap 23 to allow for tilting of the movable part 81 below the gimbal 20.
  • the sloped sections 24 slope in the - z direction from the pivot locations 22 towards the engagement locations 21.
  • the gimbal 20 comprises a planar section 25 against which the movable part 81 abuts such that the gimbal 20 can tilt together with the movable part 81.
  • the gimbal 20 comprises folds 26 at the boundary between the sloped sections 24 and the planar section 25.
  • the gimbal 20 comprises hooks 27 for engaging with the support structure 82 at the pivot locations 22.
  • FIGS. 8 and 9 show how the gimbal 20 can be embodied as a moulded component.
  • Pivot features 28 (such that the pivot has a fixed location relative to the support structure 82) is added to the corners where the gimbal 20 bears on the support structure 82. This limits the amount by which the gimbal 20 is capable of rattling around relative to the support structure 82 in normal usage.
  • the pivot features 28 are shown slotting into the support structure 82 and the vertical constraint is provided by the can 8.
  • the movable part 81 would contact the gimbal 20 in the corners by the moving crimps 41.
  • the gimbal 20 would then transfer this force through the pivot feature 28 into the can 8.
  • Figure 10 is a schematic perspective view of another gimbal 20 design.
  • Figure 11 is a schematic side on view of the gimbal 20 shown in Figure 10.
  • the gimbal 20 is formed from sheet metal.
  • the gimbal 20 is pivoted to said one of the movable part 81 and the support structure 82 via flexures 31.
  • Figures 10 and 11 show a gimbal 20 embodied as a sheet metal component.
  • the gimbal 20 comprises two flexures 31 in opposite corners that define the pivot locations 22.
  • the gimbal 20 shown in Figures 10 and 11 is formed by having pre-cut sides 29 of a sheet metal bent down and then welded at weld locations 30.
  • the movable part 81 is configured to engage with the gimbal 20 at engagement locations 21.
  • the gimbal 20 is pivoted to the support structure 82 via the flexures 31 which comprise flexure feet 32 fixed to the support structure 82.
  • the flexure feet 32 could be glued to an underside of the support structure 82 or welded to the base plate 5 of the support structure 82.
  • Figure 12 is a schematic perspective view of part of an SMA actuation apparatus 1.
  • Figure 13 is a schematic side on view of the SMA actuation apparatus 1 shown in Figure 12.
  • the gimbal 20 is a sheet metal gimbal 20 comprising flexures 34 which extend from opposite corners by the pivot locations 22, each with flexure feet 33 that are fixed (e.g. welded or glued) to the can 8 of the support structure 82.
  • the gimbal 20 comprises further opposite corners which are bent downwards and which define the engagement locations 21.
  • the movable part 81 is configured to engage the gimbal 20 at the engagement locations 21.
  • the movable part 81 is configured to tilt relative to the gimbal 20 when tilted about an axis parallel to the axis extending between the two engagement locations 21.
  • the movable part 81 is configured to tilt with the gimbal 20 when tilted about an axis parallel to the axis extending between the two pivot locations 21.
  • the gimbal 20 is pivoted to the support structure 82 and the gimbal 20 is fixed (e.g. welded) to the support structure 82 (e.g. can 8 of the support structure 82) so as to prevent translational movement of the gimbal 20 relative to the support structure 82 perpendicular to the primary axis P.
  • the gimbal 20 may instead be fixed to the movable part 81 so as to prevent translational movement of the gimbal 20 relative to the movable part 81 perpendicular to the primary axis P.
  • the gimbal 20 may be fixed to said one of the movable part 81 and the support structure 82 so as to prevent translational movement of the gimbal 20 relative to said one of the movable part 81 and the support structure 82 perpendicular to the primary axis P.
  • the above-described SMA actuator assemblies comprise an SMA wire.
  • the term 'shape memory alloy (SMA) wire' may refer to any element comprising SMA.
  • the SMA wire may have any shape that is suitable for the purposes described herein.
  • the SMA wire may be elongate and may have a round cross section or any other shape cross section.
  • the cross section may vary along the length of the SMA wire. It is also possible that the length of the SMA wire (however defined) may be similar to one or more of its other dimensions.
  • the SMA wire may be pliant or, in other words, flexible. In some examples, when connected in a straight line between two elements, the SMA wire can apply only a tensile force which urges the two elements together.
  • the SMA wire may be bent around an element and can apply a force to the element as the SMA wire tends to straighten under tension.
  • the SMA wire may be beam-like or rigid and may be able to apply different (e.g. non-tensile) forces to elements.
  • the SMA wire may or may not include material(s) and/or component(s) that are not SMA.
  • the SMA wire may comprise a core of SMA and a coating of non-SMA material.
  • the term 'SMA wire' may refer to any configuration of SMA wire acting as a single actuating element which, for example, can be individually controlled to produce a force on an element.
  • the SMA wire may comprise two or more portions of SMA wire that are arranged mechanically in parallel and/or in series.
  • the SMA wire may be part of a larger piece of SMA wire.
  • Such a larger piece of SMA wire might comprise two or more parts that are individually controllable, thereby forming two or more SMA wires.
  • the gimbal 20 is configured to pivot relative to the support structure 82.
  • the gimbal 20 may be configured to pivot relative to the movable part 81.
  • the gimbal 20 is configured to slide relative to the movable part 81.
  • this motion could occur between the gimbal 20 and the support structure.
  • the relative lateral motion between the movable part 81 and the gimbal 20 occurs through sliding contact (e.g. a plain bearing).
  • sliding contact e.g. a plain bearing
  • ball bearings or flexures could be used to enable this relative motion.
  • the flexures such as those shown in Figures 12 and 13 could enable this lateral movement between the support structure 82 and the gimbal 20.
  • any SMA actuator assembly comprising a different number of SMA wires that is also capable of tilting the movable part relative to the support structure about two orthogonal axes that are perpendicular to the primary axis may be used with any of the gimbals described herein.
  • an SMA actuator assembly comprising (a total of) four SMA wires may be used. Examples of such actuator assemblies with four SMA wires are described in, for example, W02020/074899, WO2021/209768 and W02021/209770 which are incorporated herein by reference.
  • the SMA actuation apparatus may correspond to (part of) an illumination source which may be for use in a 3D sensing system such as those described in W02020/030916 or in an augmented reality (AR) display system.
  • a 3D sensing system such as those described in W02020/030916 or in an augmented reality (AR) display system.
  • AR augmented reality
  • the movable part may be moved to achieve wobulation, for example for the display of a super-resolution image (i.e. an image having a resolution higher than that of the intrinsic resolution of the emitter or display).
  • a high-resolution image is displayed (or projected) by displaying a number of lower-resolution images at different positions in rapid succession.
  • the image displayed at each position is a lower-resolution image formed of a subset of pixels of the high-resolution image.
  • the movable part may be moved between the positions in a repeated pattern at a high frequency, for example greater than 30 Hz, preferably greater than 60 Hz, further preferably greater than 120 Hz.
  • the succession of lower-resolution images is thus perceived by the human eye as one high-resolution image.
  • the display may be a display panel, for example a LCOS (liquid crystal on silicon) display, a MicroLED display, a digital micromirror device (DMD) or a laser beam scanning (LBS) system.
  • LCOS liquid crystal on silicon
  • MicroLED digital micromirror device
  • LBS laser beam scanning
  • the emitter may be configured to emit radiation (visible light or non-visible radiation, e.g. near infrared (NIR) light, short-wave infrared (SWIR) light).
  • the emitter may comprise one or more LEDs or lasers, for example VCSELs (vertical-cavity surface-emitting lasers) or edge-emitting lasers.
  • the emitter may comprise a VCSEL array.
  • the emitter may otherwise be referred to as an illumination source and/or may comprise an image projector.
  • the display may define a plane and the primary axis may be perpendicular to the plane defined by the display. In any case, the primary axis may be aligned with a general direction in which light is emitted from the display.
  • the movable part comprises an emitter
  • the emitter may define a plane and the primary axis may be perpendicular to the plane defined by the emitter.
  • the emitter may comprise a VCSEL array and the primary axis may be perpendicular to the plane of the VCSEL array.
  • the primary axis may be aligned with a general direction in which radiation is emitted by the emitter.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Studio Devices (AREA)

Abstract

L'invention concerne un appareil d'actionnement par AMF comprenant : une partie mobile ; une structure de support ; une pluralité de fils AMF agencés, lors de la contraction, pour incliner la partie mobile par rapport à la structure de support autour d'au moins un axe d'inclinaison qui est perpendiculaire à un axe principal de l'appareil d'actionnement par AMF ; et un cardan pivotant sur l'une de la partie mobile et de la structure de support de telle sorte que le cardan est conçu pour s'incliner par rapport à ladite partie mobile et/ou à la structure de support ; le cardan étant configuré de telle sorte que le mouvement de la partie mobile par rapport à la structure de support parallèle à l'axe principal est arrêté par mise en prise entre le cardan et l'autre de la partie mobile et de la structure de support.
PCT/GB2022/053211 2021-12-13 2022-12-13 Appareil d'actionnement par amf WO2023111547A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GBGB2117964.3A GB202117964D0 (en) 2021-12-13 2021-12-13 SMA actuation apparatus
GB2117964.3 2021-12-13

Publications (1)

Publication Number Publication Date
WO2023111547A1 true WO2023111547A1 (fr) 2023-06-22

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GB (1) GB202117964D0 (fr)
WO (1) WO2023111547A1 (fr)

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011104518A1 (fr) 2010-02-26 2011-09-01 Cambridge Mechatronics Limited Appareil d'actionnement à alliage à mémoire de forme
WO2013175197A1 (fr) 2012-05-25 2013-11-28 Cambridge Mechatronics Limited Appareil d'actionnement à alliage à mémoire de forme
WO2020030916A1 (fr) 2018-08-07 2020-02-13 Cambridge Mechatronics Limited Détection 3d améliorée
US20200073140A1 (en) * 2017-03-02 2020-03-05 Cambridge Mechatronics Limited Shape memory alloy actuator assembly
WO2020074899A1 (fr) 2018-10-10 2020-04-16 Cambridge Mechatronics Limited Actionneurs en amf pour stabilisation d'image optique
WO2021209768A1 (fr) 2020-04-16 2021-10-21 Cambridge Mechatronics Limited Ensemble actionneur
WO2021209770A1 (fr) 2020-04-16 2021-10-21 Cambridge Mechatronics Limited Ensemble caméra
GB2598091A (en) * 2020-08-05 2022-02-23 Cambridge Mechatronics Ltd Actuator assembly

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011104518A1 (fr) 2010-02-26 2011-09-01 Cambridge Mechatronics Limited Appareil d'actionnement à alliage à mémoire de forme
WO2013175197A1 (fr) 2012-05-25 2013-11-28 Cambridge Mechatronics Limited Appareil d'actionnement à alliage à mémoire de forme
US20200073140A1 (en) * 2017-03-02 2020-03-05 Cambridge Mechatronics Limited Shape memory alloy actuator assembly
WO2020030916A1 (fr) 2018-08-07 2020-02-13 Cambridge Mechatronics Limited Détection 3d améliorée
WO2020074899A1 (fr) 2018-10-10 2020-04-16 Cambridge Mechatronics Limited Actionneurs en amf pour stabilisation d'image optique
WO2021209768A1 (fr) 2020-04-16 2021-10-21 Cambridge Mechatronics Limited Ensemble actionneur
WO2021209770A1 (fr) 2020-04-16 2021-10-21 Cambridge Mechatronics Limited Ensemble caméra
GB2598091A (en) * 2020-08-05 2022-02-23 Cambridge Mechatronics Ltd Actuator assembly

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