WO2006061623A1

WO2006061623A1 - Camera lens suspension

Info

Publication number: WO2006061623A1
Application number: PCT/GB2005/004722
Authority: WO
Inventors: David Livingstone; Mark Richard Shepherd
Original assignee: 1...Limited
Priority date: 2004-12-08
Filing date: 2005-12-07
Publication date: 2006-06-15
Also published as: GB2435382B; TW200641500A; GB2435382A; GB0426853D0; GB2421086A; GB0711352D0

Abstract

The suspension allows movement of a lens along the optic axis while minimising any off-axis or tilt movement. The suspension comprises two non-parallel hinged linkages. Each linkage allows movement of the lens only in the plane perpendicular to the hinges within that linkage. As the two linkages are non-parallel, movement of the lens is constrained to the line of intersection of the two movement planes. The suspension is used to suspend a lens in a camera to allow movement of the lens along the optic axis for example during focussing or zooming. The suspension may be made as a plastic moulding, possibly integral with the lens barrel, forming a compact suspension suitable for use n a miniature camera, as used for example in portable devices such as mobile phones.

Description

Camera Lens Suspension

This invention pertains to suspension systems for suspending a lens piece to allow movement along a movement axis, for example as used in a camera which may be employed in a portable electronic device such as a mobile telephone or a mobile digital data processing and/or transmitting device.

In recent years, with the explosive spread of portable information terminals sometimes known as PDAs and portable telephones, an increasing number of models incorporate a compact digital camera or digital video unit employing a CCD (charge- coupled device) or CMOS (complementary metal-oxide semiconductor) sensor as an image sensor. When such a digital camera or the like is miniaturized using an image sensor with a relatively small effective image-sensing surface area, its optical system also needs to be miniaturized accordingly.

To achieve focussing or zooming, additional drive motors have to be included in the already confined volume of such miniature cameras. Whilst most of the existing cameras rely on variations of the well-known electric-coil motor, a number of other actuators have been proposed as small drive units for the lens system. These novel drive units may include transducers based on piezoelectric, electrostrictive or magnetostrictive material. These transducers or actuators are commonly referred to as electro-active devices. Small electro-active actuators with comparably large translation displacements have been recently built using a curved structure of helically coiled piezoelectric bender tape. Such devices are found to easily exhibit displacement in the order of millimetres on an active length of the order of centimetres. These structures and variations thereof are described, for example, in the co-owned published international patent application WO-01/47041 or by D. H. Pearce et al in : Sensors and Actuators A 100 (2002), 281 -286. They are manufactured from multilayer ceramic base material such as lead zirconate titanate (PZT) and sintered at high temperatures into their final shape. The use of such actuators as drive motors for lens systems is described for example in the co-owned published international patent application WO-02/103451.

As drive units adapt to the reduced volume of the compact camera designs, lens suspensions systems, which constrain the motion of the lens holder, have to co- evolve. Lens suspension systems ideally have a low stiffness, resistive force or friction in the direction of the desired motion and high stiffness in all other directions. An example of such a suspension system is described in co-owned international patent application WO2005/003834. The suspension system described therein comprises, at its simplest, a form of four-bar link or parallelogram suspension, in which a pair of pivoted parallel links constrain a moving object to remain parallel to a support structure. Motion along the optic axis is accompanied by a much smaller sideways, or off-axis, movement. In autofocus applications, this off- axis movement has a negligible effect on the image quality. However, in zoom applications, the necessary axial movment is larger, so that the off-axis movement may be significant. This is particularly the case in high-resolution cameras where the sideways movement represents several pixels, reducing the image quality. It is therefore a purpose of the present invention to provide a suspension for movement of a lens holder along a movement axis with minimal off-axis motion. In a first aspect therefore, the invention provides a suspension system for suspending a lens holder to allow movement of the lens holder along a movement axis, the suspension system comprising: the lens holder holding at least one lens; a support structure; and at least two hinged linkages, each hinged linkage comprising a plurality of link elements connected in series by hinges, the link element at one end of the series of link elements being connected by a hinge to the support structure and the link element at the opposite end of the series of link elements being connected by a hinge to the lens holder, wherein: the hinges have a length greater than a quarter of the diameter of the at least one lens; the hinges of a respective linkage allow relative rotation of the link elements about respective hinge axes; in respect of each linkage, the hinge axes of the hinges of the linkage are parallel to each other and perpendicular to the movement axis, and in respect of different linkages, the hinge axes of the hinges are not parallel.

The suspension system allows movement of a lens holder including at least one lens. The lens holder moves along a movement axis which is usually the optical axis of the at least one lens. When applied in a camera, the lens holder moves relative to the image sensor of the camera, the casing of the device or other lenses. The lens holder may be a single lens, a group of lenses, or a lens holder such as a lens barrel holding a lens or a group of lenses. It maybe the entire lens system. The linkages may be connected directly to the element of the lens holder which holds the lens or through a suitably shaped connecting piece, for example a collar designed to fit in an appropriate groove in a lens barrel.

The suspension allows movement of the lens holder relative to a support structure. The support structure maybe the casing of the camera module or it maybe another part of the lens system. The linkages may be coupled directly or through a connecting piece. For example, the suspension may link two parts of a lens barrel, each holding one or more lenses, allowing relative movement between different lenses or lens groups.

The suspension system comprises at least two hinged linkages. The hinge axes of each linkage are parallel within the linkage. Thus, each linkage in isolation allows movement of a given point in the movable piece in one plane only, that is, the plane normal to its hinge axes. As the lens holder is driven to move up and down along the movement axis, the link elements change their angle to the movement axis and the hinge connecting the links moves sideways, in and out from the movement axis.

The hinge axes of the linkages are non-parallel. Thus, the two movement planes of the two linkages intersect at a line which is normal to the hinge axes of both linkages. Movement is therefore constrained along an axis parallel to this line, which is the movement axis. Movement along the movement axis is not accompanied by any sideways or off-axis movement. As the movement axis is the optical axis, this allows a lens or lenses to be moved along the optic axis, as is required for example in focussing or zooming. For the same reason, the suspension system causes the support piece and the moving piece to remain in the same orientation. If the lens of the lens holder is parallel to a given surface such as the surface of an image sensor, the lens holder remains parallel as it moves.

The linkages are non-parallel, that is the hinge axes of the linkages are disposed at an angle to each other. The linkages may be at any angle to each other, but an angle of 90 degrees provides the most rigid arrangement, that is, the arrangement with most resistance to sideways motion in all directions. Preferably, the centre of mass of the lens holder to be moved lies close to, or coincident with, the ^■movement axis (defined as the line of intersection of the movement planes of the centre of the two linkages), as this arrangement minimises tilting forces.

The width of the linkages, as measured by the length of the hinges, is a considerable proportion of the corresponding dimension of the moving object. This provides the advantage that, as compared to a suspension where this length is shorter, the suspension can sustain a higher torsional force without significant deformation and so the greater the length of the hinges, the greater the resistance to tilting of the lens holder. For example, the length of the hinges is preferably at least a quarter of the diameter of the at least one lens, more preferably at least a third or at least a half of the diameter of the at least one lens. Where there are plural lenses this may be the maximum diameter or the diameter of the widest lens. Alternatively, the length of the hinges is greater than half the diameter of the lens holder, and more preferably more than 80% of the diameter of the lens holder.

In the simplest form the suspension system comprises only two linkages. Additional linkages may be provided to further increase the rigidity, in which case the linkages are preferably disposed symmetrically about the movement axis. For example, the suspension may comprise three linkages disposed at 120 degrees around the movable piece, or four linkages disposed at 90 degrees. Such arrangements are symmetrical and improve the resistance to twist and tilt around the movement axis. The link elements are hinged at both ends. The hinge is a pivotal connection, that is, a connection which allows relative rotation of two members about the axis or line of the hinge or pivot. The hinge may be a conventional hinge comprising a pin extending through locating holes in both members.

Preferably, however, the hinge is a flexure, that is, a piece of material able to flex elastically. Preferably all the hinges of the linkage are flexures. For example, the link elements and flexures of a single linkage may be formed as a single piece of material, preferably a plastics material, for example selected from a group including polypropylene, polyethylene and polyamide (nylon). This is advantageous in that the suspension is robust and easily manufactured, for example by injection moulding. In this case, the end portions of the material beyond the outer flexures form part of the lens holder and the support structure respectively. The material is reduced in thickness along the desired hinge axes to form the flexures On application of an appropriate force, the locally thin material bends to allow relative rotation of the thicker, stiffer portions on either side. In one advantageous form, each link element has the form of a rectangular plate. Preferably, the link elements have a length between the hinges greater than, or equal (or comparable) to, its width in the direction along the hinge axes, its width in the direction along the hinge axes being greater than its thickness.

Within a linkage, the link elements may be identical. Alternatively, they may differ, for example, one link element may be longer than the other. Similarly, the two or more linkages of a suspension may be identical or may differ, for example in positioning of the hinges.

The linkages can in general have any number of link elements. The hinges each connect adjacent pairs of link elements in the series. To simplify the construction and minimise the degree of tilting movement allowed by looseness within the hinges, it is preferred that the linkages comprise two link elements only. In this case there are three hinges, connecting respectively: the support structure to the first link element; the first link element to the second link element; and the second link element to the lens holder. However, where space is limited, additional link elements may be included in a linkage. The sideways motion is then shared by more than one hinge. For example, a linkage comprising two link elements and three hinges may be modified to include a further hinged link element. There are then two hinges connecting a pair of link elements (i.e. excluding the hinges connecting the end link elements to the support structure and the lens holder), which hinges both move sideways, one outwards and one inwards. This may be an advantage where the space on the outside of the linkage is limited, as the outward motion is not as great as with only a single inter-link hinge.

Typically, the movement of the lens holder is driven by an actuator, preferably a piezoelectric actuator, for example of the type described in WO- 01/47041 comprising a curved structure of coiled piezoelectric bender tape.

Preferably the coil extends in a sector of a circle around the lens or lens holder. One end is fixed to the support structure while the other, moving, end is fixed to the lens barrel. On activation, the actuator drives the lens holder up and down along the movement axis. The suspension is particularly suitable for suspending a lens in a miniature camera. Such a camera may be used in, for example, a portable electronic device such as a mobile telephone, a personal digital assistant (PDA), a lap-top computer and the like. Miniature cameras are also used in for example security cameras and computer cameras such as web-cams. Such cameras are usually digital in the sense that the lens system forms an image on an electronic sensor, such as a CCD or CMOS sensor. These miniature digital cameras are considerably smaller than conventional cameras, the lens diameter typically being less than about 10 mm as compared to 15mm or more in non-miniature cameras. Typical lens diameters in miniature cameras are 5mm to 8 mm, while the complete camera module (which includes a casing, the lens system, the image sensor and any actuator(s) and suspension) for applications in portable devices is generally required to have outer dimensions of less than about 15 mm and a volume less than about 2 cm³. The suspension of the invention is particularly suited to such small devices, as it is compact, readily manufactured as a single component or a few components and easy to assemble into a camera module. Non-limitative examples of embodiments of the invention are described below with reference to the accompanying drawings. In the drawings:

Fig. 1 is a perspective view of a first suspension system;

Fig. 2 is a perspective view of a second suspension system; Fig. 3 is a top view of a third suspension system;

Fig. 4 is a vertical cross-sectional view of the third suspension system, taken along line A-A in Fig. 3;

Fig. 5 is a perspective view of a fourth suspension system;

Fig. 6 is a perspective view of a linkage of the fourth suspension system of Fig. 5;

Fig. 7 is a schematic side view of a suspension system having an additional link element;

Fig. 8 is a plan view of a suspension system having three linkages;

Fig. 9 is a schematic side view of a suspension system forming part of a lens barrel;

Fig. 10 is a schematic side view of a suspension system with link elements of unequal lengths;

Fig. 11 is a schematic side view of a suspension system with link elements hinged inwardly; and Fig. 12 is a schematic side view of a suspension system with non-identical linkages.

Fig. 1 shows an embodiment of the suspension system 11 of the invention. The support structure 12 is connected to the movable piece 13 by two hinged linkages 14 and 15. The first linkage 14 comprises two link elements 16 and 17 connected together at hinge 111. The lower link element 16 is connected to the support structure 12 by hinge 112 and the upper link element 17 is connected to the movable piece 13 by hinge 113. The three hinges 111, 112 and 113 of the first linkage 14 are parallel to each other and parallel to imaginary

The first linkage 14 therefore constrains any point in the linkage 14 and the movable piece 13 to move only in the x,z plane. Likewise, the second linkage 15 comprises link elements 18 and 19 and hinges 114, 115 and 116. The hinges 114, 115 and 116 are parallel to each other and to the imaginary x axis. Points in the second linkage 15 and the movable piece 13 are therefore constrained to move only in the y,z plane. Since the movable piece 13 is connected to both linkages 14 and 15, it is constrained to move only along the line common to both planes x,z and y,z, that is, the z direction. The suspension 11 therefore allows free movement in the up-down direction (z), denoted by the double headed arrow 117. Movement in any other direction is severely restrained by the stiffness of the linkages.

Fig. 2 shows another embodiment of the suspension of the invention in which the suspension 20 is manufactured as an integral plastic moulding with reduced thickness at the lines of the hinges, forming flexures. The reduction in thickness in Fig. 2 appears as a cut or notch on the inside of the moulding. The notch could equally well be on the outside of the moulding or the material could be notched both inside and outside to leave a thin piece in the middle (as shown in Fig. 3B below). In any of these cases, the reduction in thickness along the 'hinge' line causes the suspension to flex preferentially along these lines. Other features of Fig. 2 are similar to those of Fig. 1 and like numerals are used. Fig. 2 also shows a lens 21 and lens barrel 22 connected to the moving piece 13 of the suspension. The optic axis is denoted by a dotted line. The suspension 20 allows the lens barrel 22 to move up and down along the optical axis O.

Figs. 3 and 4 show schematic top and cross-sectional views of an embodiment of the invention as used in a miniature camera. In Fig. 3, top view, the moving piece 13 is connected to four linkages 31, 32, 33, 34. The outer perimeter 13a of the moving piece 13 is square, while the inner perimeter 13b is circular (shown as a dotted line), shaped to fit in a groove 36a around the lens barrel 36. A Helimorph^(R) piezoelectric actuator 37, shown as a long-dashed outline, fits around the lens barrel 36, within the confines of the linkages 31 to 34. At one end the actuator 37 ends in a first tab 38, which is the fixed end attached to the case of the device (not shown). At the other end, the actuator 37 ends in a tab 39 attached to the lens barrel 36, to effect movement of the lens barrel. -Si- Fig. 4 is a cross section through the right-hand half of the camera assembly of Fig. 3 taken along the line A-A¹. The linkage 31 links the movable piece 13 to the support structure 12. The support piece is fixed in the case 41, shown hatched, of the camera module. The Helimorph^ actuator 37 is shown in the space between the linkage 31 and the lens barrel 36. Also shown is the image sensor 42 attached to the case 41.

In the camera module of Figs. 3 and 4, the lens diameter is 5 mm and the diameter of the lens barrel is 7 mm. The length of the lens barrel is 7 mm. The thickness of the linkages is 0.7 mm except at the hinge parts where the thickness is 80 microns. The length of the link elements is about 3 mm and the width is about 7 mm (equal to the length of the hinges). On focussing, movement of the lens along the optic axis is up to 300 micron, causing a sideways movement of the central hinge of the suspension of about 250 microns. In a zoom camera, lens movements of up to 3 mm along the optic axis are required and sideways motion of the suspension (at the central hinge) may be 1 mm or more, depending on the dimensions of the suspension.

The camera module shown in Figs. 3 and 4 forms a device which is neat and compact, which is important in miniature cameras for use in portable electronic devices such as mobile phones. The suspension system is easy to manufacture as a plastic moulding and easy to assemble as it comprises few, possibly only one, components. The several plastic mouldings of the device, notably the lens barrel, the case and the suspension can all be manufactured to high dimensional accuracy and can readily be accurately positioned relative to each other, for example by moulded- in locating pins and sockets or by use of suitable jigs during glueing of the ends of the suspension system in place. The provision of the non-parallel hinged linkages of the invention constrains movement of the lens barrel accurately along the optic axis only, providing high quality images in zoom ad autofocus applications and in high resolution cameras.

Fig. 5 shows a fourth suspension system 200. A lens barrel 201 of a lens 202 is connected to a base 203 by two hinged linkages 203 and 205. A first one of the linkages 204 is shown in detail in Fig. 6. The first linkage 204 comprises two link elements 206 and 207 connected together by a hinge 208. The upper link element 206 is connected to two lens connecting pieces 209 by respective hinges 210. The lower link element 207 is connected to two support connecting pieces 211 by respective hinges 212. The lens connecting pieces 209 are each fixed to the lens barrel 201. Thus, the lens barrel 201 and the lens connecting pieces 209 together constitute a lens holder. The support connecting pieces 211 are each fixed to the base 203. Thus, the base 203 and the support connecting pieces 211 together constitutes a support structure. The linkage 204 allows movement of the lens holder relative to the support structure as follows.

The entire element illustrated in Fig. 6, including the two link elements 206 and 207, all the hinges 208, 210 and 212, the lens connecting pieces 209 and the support connecting pieces 211, is formed by a single piece of material, preferably a plastics material, and may be manufactured by moulding. The lens connecting pieces 209 may be manufactured together with the lens barrel 201 using a two-shot moulding process and similarly support connecting pieces 211 may be manufactured together with the base 203 using a two-shot moulding process (so that the entire moulding process maybe considered as a three-shot process).

The hinges 208, 210 and 212 are each formed by portions of material which are thinner than the remaining portions of material which constitutes the two link elements 206 and 207, the lens connecting pieces 209 and the support connecting pieces 211. In particular, the hinges 208, 210 and 212 are sufficiently thin that on movement of the lens barrel 201 relative to the base 203, the hinges 208, 210 and 212 act as a flexures providing for relative rotation of the link elements 206 and 207 relative to each other in the case of hinge 208, or relative to the lens connecting piece 209 in the case of hinge 210, or relative to the support connecting pieces 211 in the case of hinge 212. hi contrast, the link elements 206 and 207 do not flex significantly by virtue of their high thickness relative to the hinges 208, 210 and 212. hi particular, the link elements 206 and 207 have a thickness profile which increases from either end towards the center of the respective link elements 206 and 207, this profile further increasing their rigidity.

The hinges 208, 210 and 212 provide for relative rotational of the link elements 206 and 207 about respective imaginary hinge axes which are parallel to each other. The second linkage 205 has a structure which is identical to the first linkage 204 shown in Fig. 6. However, the second linkage 205 is arranged perpendicular to the first linkage 204 so that the hinge axes of the second linkage 205 are perpendicular to the hinge axes of the first linkage 204.

As each linkage 204 and 205 constrains movement of the lens barrel 201 relative to the base 203 in a plane which is perpendicular to the hinge axes of the respective linkages 204 and 205, the overall effect of both linkages 204 and 205 is to constrain movement of the lens barrel 201 relative to the support 203 along a movement axis which is the optical axis O of the lens 202. The stiffness of the fourth suspension system 200 along the movement axis is considerably lower than the stiffness of any other direction, this being for exactly the same reasons as described above for the first and second suspension systems 10 and 20.

As there are two hinges 210 between the upper link element 206 and the lens holder, in terms of reducing movement of the lens barrel 201 relative to the base 203, the two hinges 210 may each be considered as a composite hinge of length equal to the sum of the length of each of the hinges 210 and the separation between the two hinges 210. Similarly, as there are two hinges 212 between the lower link element 207 and the support structure, the two hinges 212 may each be considered as a composite hinge of length equal to the sum of the length of each of the hinges 212 and the separation between the two hinges 212.

The lens 202 focuses light onto an image sensor (not shown) mounted to the base 203 to form a miniature camera. The movement of the lens 202 along the optical axis O to provide focussing or zooming is driven by an actuator 213 which sits around the lens barrel 201 on the opposite side from the linkages 204 and 205. One end 214 of the actuator 213 is fixed to a mounting block 217 protruding from the lens barrel 201. The mounting block 217 is actually fixed to the side of the actuator 213 at that end 214. The other end 215 of the actuator 213 is fixed to the base 203 by an arm 216. The actuator 213 comprises a piezoelectric multi-layer, bender tape having an identical construction and arrangement to the actuator 37 of the third suspension system 30, as described above.

Further variants of the suspension of the invention are shown in the schematic drawings of Figs. 7 to 12.

Fig. 7 is a schematic cross-section of a suspension of the invention in which each linkage is connected to the support structure by a further hinged link element. The linkages 66 comprises link elements 41, 42 (shown as single lines) and hinges 43, 44, 45 (shown as open circles), and connects a moving piece 13 to a support structure 12 via a further link element 46 and hinge 47. The other linkages are similar. The benefit of this arrangement is that the additional link element allows smaller sideways extent and smaller sideways movement of the linkage compared to the arrangement of Fig. 2 for example.

Fig. 8 shows a plan view of a variant of the suspension of the invention comprising three linkages 51,52,53 disposed at 120 degrees about a moving piece 54. Such a suspension is symmetrical and balanced.

Fig. 9 is a schematic cross-section of an example of the suspension of the invention in which the suspension forms part of the lens barrel itself allowing relative movement between two lens groups. Two linkages 31 and 33 are shown; two further perpendicular linkages are not visible in the cross-section. The lens barrel in this case comprises two parts, an upper part 61 and a lower part 62 connected by the four linkages, hi this case, the lower part 62 of the lens barrel forms the support structure of the suspension. The upper part 61 carries a single lens 63 while the lower part carries two lenses 64 and 65. Other numbers of lenses are also possible. The suspension allows relative movement between the first lens group 63 (single lens) and the second lens group 64,65 when driven by an actuator (not shown). Such relative movement is necessary for example to maintain focus during zooming. hi a further variant, a second suspension of the invention may link the lower part of the lens barrel 62 of Fig. 9 to a fixed support such as a casing. The first suspension and actuator then provide relative movement between the two lens groups while the second suspension and actuator provide relative movement between the entire lens system and the casing. Again, such relative movements are necessary to maintain focus during zooming.

Further variants are shown schematically in Figs. 10 to 12, in which the link elements differ. In Fig. 10 the two link elements 72 and 73 forming the linkage 71 are of unequal length, hi Fig. 11 the linkage 81 bends inwards rather than outwards, hi Fig. 12, the two linkages 91 and 92 are not identical, the link elements of linkage 91 being of equal length and those of linkage 92 being of unequal length. Such variations in link elements serve to allow freedom to design the linkages to best fill the space available. (Note that the suspension systems of Figs. 10 to 12 include further linkages (not shown) in addition, in which the hinges are not parallel to the hinges of the linkages shown).

It will be apparent that many other arrangements of lenses and suspension systems fall within the scope of the invention.

Claims

1. A suspension system for suspending a lens holder to allow movement of the lens holder along a movement axis, the suspension system comprising: the lens holder holding at least one lens; a support structure; and at least two hinged linkages, each hinged linkage comprising a plurality of link elements connected in series by hinges, the link element at one end of the series of link elements being connected by a hinge to the support structure and the link element at the opposite end of the series of link elements being connected by a hinge to the lens holder, wherein: the hinges have a length at least a quarter of the diameter of the at least one lens; the hinges of a respective linkage allow relative rotation of the link elements about respective hinge axes; in respect of each linkage, the hinge axes of the hinges of the linkage are parallel to each other and perpendicular to the movement axis, and in respect of different linkages, the hinge axes of the hinges are not parallel.

2. A suspension system according to claim 1, wherein the hinges are flexures.

3. A suspension system according to claim 2, wherein the link elements and flexures of each linkage are made as a single piece of material.

4. A suspension system according to any one of the preceding claims, wherein the link elements are made of moulded plastic.

5. A suspension system according to any one of the preceding claims, wherein the suspension comprises two linkages.

6. A suspension system according to claim 5, wherein the hinge axes of hinges of the two linkages are at 90° to each other.

7. A suspension system according to any one of claims 1 to 4, wherein the suspension comprises three or more linkages disposed symmetrically about the movement axis.

8. A suspension system according to any one of the preceding claims, wherein the link elements all have the same length between the hinges.

9. A suspension system according to any one of the preceding claims, wherein the hinges have a length at least a half the diameter of the at least one lens.

10. A suspension system according to any one of claims 1 to 8, wherein the hinges have a length greater than a half of the diameter of the lens holder.

11. A suspension system according to claim 10, wherein the hinges have a length greater than 80% of the diameter of the lens holder.

12. A suspension system according to any one of the preceding claims, wherein the at least one lens has a diameter less than 10mm.

13. A suspension system according to any one of the preceding claims, wherein the lens holder is a lens barrel.

14. A suspension system according to any one of the preceding claims, wherein the linkages each comprise two link elements and three hinges, the three hinges connecting respectively: the support structure to the first link element; the first link element to the second link element; and the second link element to the lens holder

15. A suspension system according to any one of the preceding claims, further comprising an actuator coupled between the support structure and the lens piece to drive movement of the lens piece relative to the support structure.

16. A suspension system according to claim 15, wherein the actuator is an electro-active actuator.

17. A suspension system according to claim 16, wherein the actuator is a ceramic actuator.

18. A suspension system according to claim 16 or 17, wherein the actuator is a bender extending in a helix around an axis which is curved.

19. A camera including a suspension system according to any one claims 15 to 18.

20. A portable electronic device including a camera according to claim 19.