Abstract: A camera apparatus capable of providing optical image stabilisation comprises: a support structure; a camera unit comprising an image sensor and a lens system; a suspension system comprising a plurality of flexure elements supporting the camera unit on the support structure in a manner allowing the camera unit to tilt; and a plurality of SMA actuators each formed as SMA wire connected between the camera unit and the support structure and arranged on contraction to drive tilting of the camera unit. The SMA wire may be fixed to the camera unit at its ends and hooked over an element of the support structure. A vibration sensor, whose output is used as the basis for generating drive signals, may be mounted on the camera unit.

Abstract: A shape memory alloy actuation apparatus comprises a movable element suspended on a support structure by a plurality of flexures which are non-uniformly configured to apply forces having differing components perpendicular to the movement axis generating a net moment around the centre of mass of the movable element in an opposite sense from the moment generated by the actuation force. A shape memory alloy wire is coupled between the support structure and an intermediate body engaging the movable element through a pivotal contact to avoid lateral force transfer. Also coupled between the support structure and the intermediate body is a resilient biassing flexure plastically deformed in a partial region thereof. The shape memory alloy wire is crimped by a crimping member fixed to the support structure holding the shape memory alloy wire against a curved surface from which the shape alloy memory wire extends to the movable element.

Abstract: A miniature camera lens actuation apparatus employs an SMA actuator comprising SMA wire to move a camera lens element. To provide autofocus, the SMA actuator is heated across its range of contraction and the resistance at which the focus is at an acceptable level is stored. To combat hysteresis, there is performed a flyback in which the SMA actuator is cooled, before heating the SMA actuator to the stored resistance. The stored resistance is adjusted to combat creep caused by non-linear heating of the SMA actuator. The SMA wire has conductive material extending along on a portion of the SMA wire which extends from a member connected to the SMA wire and being in electrical connection with the SMA wire in order to short out that portion of the SMA wire to reduce creep. Additional material is applied over the SMA wire and the member to reduce fatigue.

Abstract: A shape memory alloy actuation apparatus comprises a movable element supported on a support structure by a suspension system comprising a plurality of resilient flexures. A shape memory alloy actuator drives movement of the movable element on contraction. An end-stop limits the movement of the movable element in the opposite direction. Rather than using the resilient flexures of the suspension system as the sole biassing means, an additional Massing element biasses the movable element against the SMA actuator. When the moveable element is held against the end-stop, the force applied by the biassing element is greater than the force applied by the flexures of the suspension system. This reduces the design constraints, for example allowing a greater range of movement.

Abstract: An SMA actuation arrangement comprises: an SMA actuator arranged on contraction caused by heating to drive movement of a movable element relative to a support structure; a current source operative to supply drive current through the SMA actuator to heat the SMA actuator; and a detector circuit operative to detect a measure of the resistance of the SMA actuator. Whilst detecting a measure of the resistance of the SMA actuator and controlling the drive current on the basis of the measure of the resistance of the SMA actuator; there is derived a measure of an electrical characteristic of the SMA actuator that is representative of the ambient temperature. Whilst applying closed-loop control an offset is added to the control signal which reduces the steady-state value of an error between the measure of the resistance of the SMA actuator and a target value.

Abstract: A miniature camera lens actuation apparatus provides an auto-macro function in which a camera lens element has two focus positions. In one type of apparatus, a shape memory alloy actuator arranged to drive movement of the camera lens element relative to a support structure against an end-stop arranged to limit the movement. The shape memory alloy actuator is connected to one of the movable element and the support structure by a compliant connector. This limits the stresses on the shape memory alloy actuator and therefore increases its lifetime. In another type of apparatus, the suspension system supporting the movable element on the support structure provides the movable element with two stable positions along the movement direction.

Abstract: A miniature camera lens actuation apparatus employs an SMA actuator comprising SMA wire to move a camera lens element. To provide autofocus, the SMA actuator is heated across its range of contraction and the resistance at which the focus is at an acceptable level is stored. To combat hysteresis, there is performed a flyback in which the SMA actuator is cooled, before heating the SMA actuator to the stored resistance. The stored resistance is adjusted to combat creep caused by non-linear heating of the SMA actuator. The SMA wire has conductive material extending along on a portion of the SMA wire which extends from a member connected to the SMA wire and being in electrical connection with the SMA wire in order to short out that portion of the SMA wire to reduce creep. Additional material is applied over the SMA wire and the member to reduce fatigue.

Abstract: A miniature camera lens actuation apparatus comprises a support structure, a camera lens element supported on the support structure by a suspension system; and an SMA actuator connected between the support structure and the movable element to drive movement of the camera lens element. The control circuit may include a drive circuit and a sensor circuit which have separate electrical connections to the SMA actuator to reduce the impact of the resistance of the electrical connections on the sensing. The control circuit may vary the drive signal in response to a temperature signal indicative of the ambient temperature. An endstop limits movement to prevent extension of the SMA actuator in its unheated state beyond a maximum length which is at or below the length corresponding the local maximum resistance of the resistance-length curve. Control of position is effected using resistance of the SMA actuator as a measure of position.

Abstract: A camera lens actuation apparatus for driving motion of a camera lens supported on a support structure by a suspension system. The apparatus incorporates a subassembly comprising SMA wire connected to at least one mounting member which is mounted to the support structure. At least one pair of lengths of SMA wire are held in tension between the camera lens element and the support structure at respective acute angles to the optical axis applying a tensional force having a component along the optical axis. The lengths of SMA wire in the pair are held at angle as viewed along the optical axis. There may be plural pairs with a balanced arrangement in which the forces generated have no net component perpendicular to the optical axis and generate no net torque around any axis perpendicular to the optical axis. A control circuit controls heating of the SMA wire in response to a measure of its resistance.

Abstract: A piezoelectric device comprising a continuous piezoelectric element (10) extending alternately back and forth to form a plurality of parallel, straight portions (14) arranged in a stack with intermediate linkage portions (15) at alternate ends of the straight portions (14). Each straight portion (14) is constructed and arranged with electrodes (12, 13) to bend, on activation, in the stacking direction in which the straight portions (14) are stacked with opposite curvature in two halves (16, 17) of the straight portion (14) to create displacement between the ends of the straight portion (14) in the stacking direction adding in series through the stack. The continuous nature of the piezoelectric element (10) eases manufacture. Devices with two types of construction are disclosed. Firstly, the continuous piezoelectric element (10) may have a bender construction such as a bimorph bender construction.

Abstract: A loudspeaker comprises the casing (22) of a portable electronic device, having mounted thereon a sound generating element (21) which may be a transparent cover for a display. The sound generating element (21) is driven to generate sound by a piezoelectric actuator (1) extending along a sector of a circle and coupled at one end (7) to the casing (22) by a first block (24) and at the other end (8) to the edge (26) of the sound generating element (21) by a second block (25). The first block (24) and the second block (25) each have stop surfaces spaced apart from each other and capable of engaging each other to limit the amount of relative movement of the ends (7) and (8) of the actuator (1) to prevent damage to the actuator (1). The sound generating element (21), the first and second blocks (24) and (25) and the actuator (1) form an assembly which may be manufactured for subsequent assembly to the casing (22).

Abstract: A loudspeaker for audible sound is described having a sound emitting element mounted onto a support structure and at least one actuator adapted to rotate said sound emitting element around a hinge section, wherein the actuator is made of piezoelectric material. In variants the actuator forms part of the hinge section and the loudspeaker is capable of generating vibrations through its support structure.

Abstract: A loudspeaker comprises a sound generating element mounted on a support structure, and two rotary actuators I mounted at opposing edges of the sound generating element. The actuators are operable to drive motion of the sound generating element relative to the support structure including a component of rotation. The loudspeaker produces a greater sound output than if driven at one edge only, and is particularly suitable for use in a portable electronic device such as a mobile telephone, in which case the support structure may be a portion of the casing of the, device and the sound generating element maybe a transparent panel covering a display device.

Abstract: An example housing that protects a ceramic actuator from excessive and damaging displacement comprises a protective structure arranged to limit the motion of the actuator by contacting at least one section of the actuator between fixed and moving terminals of said actuator. A suspension system for a lens holder of a miniature camera actuated by a ceramic actuator comprises four pivotally connected link elements in form of a parallelogram connected between a housing and the lens holder.

Abstract: A loudspeaker comprises a support which may be a portion of the housing of an electronic device and a diaphragm mounted on the support. A piezoelectric actuator arranged to bend on activation providing relative movement between two ends of the actuator is coupled at each of its ends to the diaphragm to vibrate the diaphragm on activation and generate sound. One end of the actuator coupled to a portion of the diaphragm at the edge of the diaphragm is fixed relative to the support.

Abstract: An equivalent to the spatial separation either side of a nominal median plane that is inherent in a bimorph (with one piezoelectric layer on one side, and the second on the other side of the plane) is attained by structurally shaping the cross-section of a simple, single piezoelectric layer (11) such that it has a multiplicity of piezoelectric portions arranged in two generally-planar groups one either side of a median plane, so that any dimension change undergone by a portion on one side of that plane will tend to bend the whole device in the opposite direction to the same sense dimension change undergone by a portion on the other side of that plane. The simple, single layer acts as though it were a bimorph if elongate and beam-like, bending along its length, one end moving up/down, or back/forth, relative to the other but with any need for an internal, electrode.

Abstract: Electro-active actuators (310) and methods of manufacturing such actuators are described with such actuators (310) having a plurality of electro-active segments (311) arranged along a curved line with each segment (311) being essentially planar and coupled to adjacent segments (311) through joint sections (312) placed at opposite corners of the segment (311). The actuators (310) exhibit a displacement in a different direction than the direction of displacement of a segment when seen in isolation. They can be made from a continuous tape of material, preferably by die punching.

Abstract: A housing that protects a ceramic actuator from excessive and damaging displacement comprises a protective structure arranged to limit the motion of the actuator by contacting at least one section of said actuator between fixed and moving terminals of said actuator. A suspension system for a lens holder of a miniature camera actuated by a ceramic actuator comprises four pivotally connected link elements in form of a parallelogram connected between a housing and the lens holder.

Abstract: A camera comprises: a support structure 100; a lens holder 120 holding at least one lens 121; a suspension 130 for mounting said lens holder 120 on the support structure 100 to allow relative movement of the lens holder 120 and the support structure; and an actuator for moving said lens holder 120. The suspension 130 includes two link elements 133, 135 each connected at a first end to the support structure 100 by a pivotal connection and at the other, second end to the lens holder 120 by a pivotal connection, the pivotal connections allowing pivoting of the respective link element 133, 135 around a respective pivot axis, all the pivot axes being parallel, and the extent of the two link elements 133, 135 perpendicular to their respective pivot axes being parallel and of equal length.

Abstract: An apparatus for manufacturing a ceramic device from tape (21) in a green state comprises a cylindrical rod (23) as a first forming element, a first clamping system (241) for fixing a first end of the tape (21) with respect to the cylindrical rod (23) and a first mechanism (20, 231) for winding the tape (21) around the cylindrical rod (23) to preform the tape (21). The apparatus further comprises a second forming element (33), a second clamping system (351, 352) for fixing at least one end of the pre-formed tape (21) with respect to the second forming element (33), and a second mechanism (331, 351) which winds the pre-formed tape (21) around the second forming element (33).