CN116615909A

CN116615909A - Actuator assembly

Info

Publication number: CN116615909A
Application number: CN202180072157.3A
Authority: CN
Inventors: 安德鲁·本杰明·辛普森·布朗; 罗宾·爱丁顿; 斯蒂芬·马修·邦廷; 康斯坦丁诺斯·潘特里迪斯
Original assignee: Cambridge Mechatronics Ltd
Current assignee: Cambridge Mechatronics Ltd
Priority date: 2020-09-29
Filing date: 2021-09-29
Publication date: 2023-08-18
Also published as: WO2022069888A1; GB202306466D0; GB202015414D0; GB2615465A

Abstract

An actuator assembly, comprising: a support structure; an image sensor assembly comprising an image sensor having a photosensitive region, wherein the image sensor assembly is supported on a support structure such that a gap is formed between the image sensor assembly and the support structure on a side of the image sensor assembly facing away from the photosensitive region; and a region of heat transfer material disposed in the gap, wherein the heat transfer material is arranged to transfer heat between the image sensor assembly and the support structure, and wherein the heat transfer material is configured to deform to allow the image sensor assembly to move relative to the support structure.

Description

Actuator assembly

The present invention relates to actuator assemblies, and in particular to actuator assemblies in which Optical Image Stabilization (OIS) and/or super-resolution imaging is provided.

In cameras, the purpose of OIS is to compensate for camera shake, i.e. camera vibration, typically caused by user hand movements, which reduces the quality of the image captured by the image sensor. Mechanical OIS typically involves an actuator device that detects vibrations by a vibration sensor, such as a gyroscopic sensor, and controls an adjustment camera device to compensate for the vibrations based on the detected vibrations. Several techniques for adjusting camera devices are known. OIS is in principle possible by processing the captured image, but requires a powerful processing capability. Therefore, mechanical OIS has been developed in which the optical system of the camera is mechanically adjusted.

Many actuator devices using mechanical OIS technology are known and successfully applied in relatively large camera devices, such as digital still cameras, but are difficult to miniaturize. Cameras have become very popular in a wide range of portable electronic devices (e.g., mobile phones and tablet computers), and miniaturization of cameras is important in many such applications. The very tight packaging of components in miniature camera devices presents great difficulty in adding OIS actuators to the desired packaging.

In one type of mechanical OIS, a camera unit comprising an image sensor and a lens assembly for focusing an image on the image sensor is tilted relative to a support structure about two nominal axes perpendicular to each other and to a photosensitive area of the image sensor. This type of OIS will be referred to herein as "OIS module tilting". WO-2010/029316 and WO-2010/089529 each disclose an actuator assembly of this type in which a plurality of Shape Memory Alloy (SMA) wires are arranged to drive tilting of a camera unit.

In another type of mechanical OIS, the lens assembly is moved orthogonal to the optical axis of at least one lens. This type of OIS will be referred to herein as "OIS lens shift". WO-2013/175197 and WO-2014/083318 each disclose an actuator assembly of this type in which a plurality of SMA wires are arranged to drive movement of a lens assembly.

WO-2017/072525 discloses an image sensor mounted on a carrier which is suspended on a support structure by means of a sliding bearing (slide bearing) which allows the carrier and the image sensor to be moved relative to the support structure in any direction transverse to the photosensitive area of the image sensor. An actuator assembly comprising a plurality of SMA wires is arranged to move the carrier and the image sensor relative to the support structure to provide OIS of an image captured by the image sensor.

In addition to OIS, accurate control and positioning of the image sensor assembly is also useful in other applications. For example, super-resolution imaging may be achieved by combining two or more images captured at positions offset from each other by a sub-pixel distance. Therefore, it may be desirable for the image sensor to be positioned with a positioning accuracy of 0.5 μm or less relative to the support structure. Such accurate positioning may require actuator members that can be reliably controlled to apply high actuation forces to move and position the image sensor and/or to reduce friction between the image sensor assembly and the support structure.

The present invention relates to an alternative actuator assembly that exhibits reduced friction between an image sensor assembly and a support structure while maintaining adequate heat transfer between the image sensor assembly and the support structure. The present invention is also directed to providing an improved actuator assembly for applications requiring precise position control, such as super-resolution imaging.

According to the present invention, there is provided an actuator assembly comprising: a support structure; an image sensor assembly comprising an image sensor having a photosensitive region, wherein the image sensor assembly is supported on a support structure such that a gap is formed between the image sensor assembly and the support structure on a side of the image sensor assembly facing away from the photosensitive region; and a region of heat transfer material disposed in the gap, wherein the heat transfer material is arranged to transfer heat between the image sensor assembly and the support structure, and wherein the heat transfer material is configured to deform to allow the image sensor assembly to move relative to the support structure.

The provision of the gap reduces friction between the image sensor assembly and the support structure. This may ultimately allow for a more accurate positioning of the image sensor assembly relative to the support structure, for example for super resolution imaging purposes. The heat transfer material in the gap improves the transfer of heat away from the image sensor and to the support structure. Thus, the support structure may serve as a heat sink for the image sensor. The deformability of the heat transfer material ensures that the image sensor assembly remains movable, as is required for OIS applications and/or super resolution imaging, for example.

According to the present invention there is also provided an actuator assembly comprising: a support structure; an image sensor assembly including an image sensor having a photosensitive region; a plurality of SMA wires arranged to enable movement of the image sensor assembly relative to the support structure in any direction transverse to the photosensitive region when selectively actuated; and a control circuit configured to drive the SMA wire so as to controllably move the photosensitive region to two or more positions, wherein the two or more positions are offset from each other in a direction parallel to the photosensitive region by a distance less than a pitch between pixels of the photosensitive region.

Due to the high actuation force of the SMA wires, the SMA wires are able to control the movement and positioning of the image sensor assembly relative to the support structure particularly accurately. Controllable movement by sub-pixel distance enables the actuator assembly to be used in applications such as super-resolution imaging. Positioning accuracy may be further improved by reducing friction between the image sensor assembly and the support structure, for example by providing a gap between the image sensor assembly and the support structure. The gap may be formed by supporting the image sensor assembly on a support structure using roller bearings or flexures. Areas of heat transfer material may be provided in the gaps to increase the transfer of heat between the image sensor assembly and the support structure.

According to the present invention there is also provided an actuator assembly comprising: a support structure; a moving part supported on the support structure, wherein one of the support structure and the moving part comprises an image sensor having a photosensitive area; and a bearing device (bearing arrangement) configured to support the moving part on the support structure, wherein the bearing device is configured to allow the moving part to move relative to the support structure; wherein at least one of the support structure and the moving part comprises at least one plate provided with a hole (hole) extending at least partially through the plate for receiving the bearing means.

The hole accommodates the support. This may help to reduce the height of the actuator assembly, i.e. the size of the plate forming the actuator assembly in the thickness direction.

According to the present invention there is also provided an actuator assembly comprising: a support structure; an image sensor assembly comprising an image sensor having a photosensitive region, wherein the image sensor assembly is supported on a support structure; one or more bearings configured to support the image sensor assembly on a support structure, the one or more bearings configured to allow movement of the image sensor assembly relative to the support structure; and a supporting impact protection structure comprising a cantilever structure, the cantilever structure being included in the support structure or the image sensor assembly, one or more supports being located on a free end of the cantilever structure.

According to the present invention there is also provided an actuator assembly comprising: a support structure; a moving part supported on the support structure, wherein one of the support structure and the moving part comprises an image sensor having a photosensitive area; one or more bearings configured to support the moving component on a support structure, the one or more bearings configured to allow the moving component to move relative to the support structure; and a supporting impact protection structure comprising a cantilever structure, the cantilever structure being included in the moving part, the one or more supports being located on a free end of the cantilever structure.

Generally, in normal operation, the support enables the image sensor assembly to move parallel to a plane in which the photosensitive region extends. In the event of an impact, the cantilever deflects, thereby absorbing energy and protecting the support and/or support surface.

According to the present invention there is also provided an actuator assembly comprising: a support structure; an image sensor assembly comprising an image sensor having a photosensitive region, wherein the image sensor assembly is supported on a support structure; and a flexure device configured to support the image sensor assembly on the support structure in a manner that allows the image sensor assembly to move relative to the support structure in any direction parallel to a plane in which the photosensitive region extends and/or in a manner that allows the image sensor assembly to rotate about any axis orthogonal to the plane in which the photosensitive region extends.

The flexure means comprises one or more flexures. Typically, the image sensor assembly is supported on the support structure only by the flexure means, e.g. without any additional (sliding or ball) bearings. Generally, in normal operation, the flexure device constrains movement of the image sensor assembly perpendicular to a plane in which the photosensitive region extends.

According to the present invention there is also provided an actuator assembly comprising: a support structure; a moving part supported on the support structure, wherein one of the support structure and the moving part comprises an image sensor having a photosensitive area; and a flexure device configured to support the moving member on the support structure in a manner that allows the moving member to move relative to the support structure in any direction parallel to a plane in which the photosensitive region extends and/or in a manner that allows the moving member to rotate about any axis orthogonal to the plane in which the photosensitive region extends, wherein the flexure device comprises three or more beams that extend between the moving member and the support structure in a direction perpendicular to the photosensitive region, wherein each beam comprises a first portion and a second portion that are parallel to each other and each extend in a direction perpendicular to the photosensitive region, wherein the first portion is connected to the moving member at one end and the second portion is connected to the support structure at one end, and wherein the other end of the first portion and the other end of the second portion are connected to each other.

Typically, the moving part is supported on the support structure only by the flexing means, e.g. without any additional (sliding or ball) bearings. Generally, in normal operation, the flexure device constrains movement of the moving part perpendicular to a plane in which the photosensitive region extends. The flexure means may help reduce friction between the moving member and the support structure.

According to the present invention there is also provided an actuator assembly comprising: a support structure defining a main plane; a moving part configured to receive the image sensor; a plurality of SMA wires arranged to enable movement of the moving part relative to the support structure in any direction parallel to the main plane and/or to enable rotation of the moving part about any axis orthogonal to the main plane; and one or more end stops configured to limit movement of the moving member relative to the support structure, wherein each end stop includes a surface area included in the support structure and a surface area included in the moving member.

The actuator assembly need not include an image sensor or any other components that are incorporated in the normal assembly order after the image sensor. Thus, the actuator assembly (including the end stop) may be tested prior to attaching the image sensor.

The invention provides particular advantages when applied to an actuator assembly for miniature cameras, for example in the case where the photosensitive area has a diagonal length of at most 12 mm or 15 mm.

For a better understanding, embodiments of the invention will now be described by way of non-limiting example with reference to the accompanying drawings, in which:

FIG. 1 is a schematic cross-sectional view of a camera device including an actuator assembly;

FIG. 2 is a cross-sectional view of an actuator assembly including a roller support;

FIG. 3 is a perspective view of a moving plate of the carrier of the actuator assembly;

FIG. 4 is a plan view of the actuator assembly from above;

FIG. 5 is a cross-sectional view of an actuator assembly including another roller support;

FIG. 6 is a cross-sectional view of an actuator assembly including another roller support;

FIG. 7 is a perspective view of an actuator assembly including a flexure device;

FIG. 8 is a perspective view of another flexure device;

FIG. 9 is a perspective view of another flexure device;

FIG. 10 is a perspective view of another flexure device;

FIGS. 10a and 10b schematically depict an example of moving an image sensor assembly using the flexure device of FIG. 10;

FIG. 11 is a cross-sectional view of a portion of an actuator assembly showing a gap and a heat transfer material;

FIGS. 12 and 13 are plan views of regions of heat transfer material disposed in the gaps and on the support structure;

FIG. 14 is a cross-sectional view of a portion of an actuator assembly showing another arrangement of gaps and heat transfer material;

fig. 15-17 are cross-sectional views of alternative actuator assemblies;

FIG. 18 is another cross-sectional view of the actuator assembly of FIG. 15;

FIG. 19 is a perspective view of a support impact protection structure;

FIG. 20 is a perspective view of a portion of an image sensor assembly having a receiving support; and

fig. 21 is a cross-sectional view of the apparatus shown in fig. 20.

In fig. 1 a camera device 1 comprising an actuator assembly 2 according to the invention is shown, fig. 1 being a cross-sectional view taken along an optical axis O. In the depicted embodiment, the actuator assembly 2 is a sensor displacement assembly. The camera device 1 will be comprised in a portable electronic device such as a mobile phone or tablet. Miniaturization is therefore an important design criterion.

The actuator assembly 2 is shown in detail in fig. 2 to 4, fig. 2 being a side view of the actuator assembly 2, fig. 3 being a perspective view of the moving plate 9 of the carrier 8 of the actuator assembly 2; and figure 4 is a plan view of the actuator assembly 2. The flexure 67 described below is omitted from fig. 2 and 4 for clarity. The actuator assembly 2 may be manufactured first and then the actuator assembly 2 is assembled with other components of the camera device 1.

The actuator assembly 2 comprises a support structure 4. An image sensor assembly 12 is supported on the support structure 4. The image sensor assembly 12 includes an image sensor 6 having a photosensitive area 7 and typically also includes a Printed Circuit Board (PCB) on which the image sensor 6 is mounted. When incorporated into the camera device 1, the photosensitive region 7 is aligned with and perpendicular to the optical axis O. The image sensor 6 captures an image and may be of any suitable type, for example a CCD (charge coupled device) or CMOS (complementary metal oxide semiconductor) device. As is conventional, the image sensor 6 has a rectangular photosensitive area 7. The photosensitive region 7 may comprise an array of pixels. Without limiting the invention, in this example the camera device 1 is a miniature camera in which the photosensitive area 7 has a diagonal length of at most 12 mm.

Optionally, the image sensor assembly 12 comprises a carrier 8, the carrier 8 comprising a moving plate 9. The image sensor 6 may be mounted on a carrier 8, in particular on a moving plate 9. The moving plate 9 may be formed of a sheet material, which may be metal, for example, steel such as stainless steel. The moving plate 9 is shown separately in fig. 3 and includes a flexure 67, the flexure 67 being described in more detail below.

Although in this example the carrier 8 comprises a single moving plate 9, alternatively the carrier 8 may comprise other layers that may be attached to the moving plate 9 or laminated with the moving plate 9.

Alternatively, the support structure 4 comprises a support plate 5, which support plate 5 may be formed of a sheet-like material, which may be a metal, e.g. steel, such as stainless steel.

Although in this example the support structure 4 comprises a single support plate 5, alternatively the support structure 4 may comprise other layers that may be attached to the support plate 5 or laminated with the support plate 5.

The support structure 4 further comprises a border portion 10, which border portion 10 is fixed to the front side of the support plate 5 and extends around the support plate 5. The border portion 10 has a central aperture 11.

The camera device 1 and/or the portable electronic device in which the camera device 1 is integrated comprise an Integrated Circuit (IC) chip 30 and a gyro sensor 31, which Integrated Circuit (IC) chip 30 and gyro sensor 31 are fixed on the rear side of the support plate 5 in the example shown. The control circuit described further below is implemented in the IC chip 30.

The image sensor assembly 12 is supported on the support structure 4 in a manner that allows the image sensor assembly 12 to move relative to the support structure 4 in any direction transverse to the photosensitive region 7 (i.e., transverse to the optical axis O and parallel to the plane in which the photosensitive region 7 extends). Thus, the image sensor assembly 12 can be supported in such a manner as to suppress movement of the image sensor assembly 12 in a direction perpendicular to the photosensitive region 7. The image sensor assembly 12 is also supported on the support structure 4 in a manner that allows the image sensor assembly to rotate about any axis parallel to the optical axis O (i.e., parallel to any axis orthogonal to the plane in which the photosensitive region extends). Thus, the image sensor assembly 12 may be supported in a manner that inhibits tilting or rotation of the image sensor assembly 12 about any axis parallel to the photosensitive region 7.

WO-2017/072525 discloses the use of a sliding bearing for supporting an image sensor assembly on a support structure in a manner allowing the above-mentioned movement. Such a sliding bearing comprises two bearing surfaces, which bear against each other, allowing a relative sliding movement. Such a sliding bearing may be compact and facilitate heat transfer between the image sensor assembly and the support structure. However, in certain applications, it may be desirable to reduce friction between the image sensor assembly and the support structure as compared to arrangements in which a sliding bearing is provided. Such applications include, for example, super resolution imaging using image sensor assemblies.

In the illustrated embodiment, the image sensor assembly 12 is supported on the support structure 4 such that a gap 104 is formed between the image sensor assembly 12 and the support structure 4. The gap 104 is formed on the side of the image sensor component 12 facing away from the photosensitive region 7, in particular in a direction perpendicular to the photosensitive region 7. A gap 104 is formed in particular between the moving plate 9 and the support plate 5. The provision of the gap 104 reduces friction between the image sensor assembly 12 and the support structure 4. This enables the image sensor assembly 12 to be moved and positioned more accurately with respect to the support structure 4.

The actuator assembly 2 further comprises a region of heat transfer material 103 arranged in the gap 104. The heat transfer material 103 transfers heat between the image sensor assembly 12 and the support structure 4. The heat conduction between the image sensor assembly 12 and the support structure 12 is increased compared to the case where the heat transfer material 103 is not provided. The heat transfer material 103 spans the gap 104 in a direction perpendicular to the photosensitive region 7. Thus, the heat transfer material 103 is in direct contact with the surface of the support structure 4 facing the gap 104 and the surface of the image sensor assembly 12 facing the gap 104.

The region of the heat transfer material 103 may have a thermal conductivity of greater than 0.02W/K, preferably greater than 0.1W/K, further preferably greater than 0.2W/K. For this purpose, the heat transfer material 103 may have a thermal conductivity of more than 0.02W/mK, preferably more than 0.1W/mK, further preferably more than 0.2W/mK. The heat transfer material 103 may comprise thermally conductive particles, such as metal particles. Such thermally conductive particles may increase the thermal conductivity of the heat transfer material 103.

The heat transfer material 103 deforms to allow the image sensor assembly 12 to move relative to the support structure 4. In particular, the heat transfer material 103 undergoes shear deformation as the image sensor assembly 12 moves relative to the support structure 4. Sliding between the heat transfer material 103, the image sensor assembly 12, and/or the support structure 4 may be avoided, thereby avoiding or reducing friction between the movable and stationary components of the actuator assembly 2. The heat transfer material 103 may have a shear modulus in a direction parallel to the photosensitive region 7 of less than 100kPa, preferably less than 10kPa, further preferably less than 1 kPa. For example, the heat transfer material 103 may include one or more of silicone rubber or any other rubber, gel (e.g., hydrogel or organogel), and liquid. The liquid may be a shear-thinning liquid, for example a liquid having a viscosity that decreases by more than a factor of 1000 under shear.

The region of heat transfer material 103 may fill the gap 104, for example as shown in fig. 2. Accordingly, the contact area between the heat transfer material 103 and the image sensor assembly 12 may be equal to or greater than the area of the photosensitive region 7. Alternatively, the area of the heat transfer material 103 may partially fill the gap 104, so the contact area between the heat transfer material 103 and the image sensor assembly 12 may be smaller than the area of the photosensitive area 7. Generally, the total contact area of the heat transfer material 103 with the image sensor assembly 12 is at least 0.1 times, preferably in the range of 0.2 to 4 times, further preferably in the range of 1 to 4 times the area of the photosensitive region 7.

The gap 104 or in particular the height of the heat transfer material 103 in the gap 104, i.e. the extent in the direction perpendicular to the photosensitive region 7, may be selected to control the heat transfer between the image sensor assembly 12 and the support structure 4. In general, the minimum height of gap 104 may be large enough to avoid contact between image sensor assembly 12 and support structure 12 in gap 103 during movement of image sensor assembly 12. Thus, the minimum height of the gap 104 is greater than the surface flatness of the surface of the image sensor assembly 12 facing the gap 104 and/or the surface of the support structure 4 facing the gap 104. The minimum height of the gap 104 may be greater than 10 μm, preferably greater than 20 μm, further preferably greater than 50 μm. The height of the gap 104 may be small enough to ensure adequate heat transfer between the image sensor assembly 12 and the support structure 4. The smaller gap 104 also ensures that the actuator assembly 2 remains compact. The height of the gap 104 or the heat transfer material 103 may be less than 1mm, preferably less than 300 μm, further preferably less than 200 μm, most preferably less than 100 μm.

The minimum height of the heat transfer material 103 may be large enough to allow the image sensor assembly 12 to move relative to the support structure 4 within a desired range of movement of OIS, for example within a range of movement of at least 100 μm, preferably at least 200 μm. Thus, the minimum height of the heat transfer material 103 may depend on the flexibility of the heat transfer material 103. Typically, the height of the heat transfer material may be in the range of 20 μm to 300 μm, preferably 50 μm to 150 μm.

The gap may have a substantially uniform height, as shown in fig. 11. Alternatively, as shown in fig. 14, the support structure 4 may comprise a recess on the surface facing the gap 104. Additionally or alternatively, the image sensor assembly 12 may include a recess (not shown) on a surface facing the gap 104. Fig. 14 shows the gap 104 having a stepwise variable height, but in general the height of the gap 104 may be varied in any other way. The region of the heat transfer material 103 may be arranged within the recess, i.e. in the region of the gap 104 having a larger height. This allows the height of the heat transfer material 103 to be increased, thereby increasing the flexibility of the area of the heat transfer material 103 and the range of movement of the image sensor assembly. At the same time, the minimum height of the gap 104 is kept small, thus increasing the heat transfer across the gap 104 in the areas where the heat transfer material 103 is not provided.

The region of the heat transfer material 103 may be patterned. For example, the regions of heat transfer material 103 may be disposed in a plurality of separate regions. Fig. 12 shows in plan view the areas of the heat transfer material 103 formed as five points. Fig. 13 shows an alternative mode of the heat transfer material 103, in which the region of the heat transfer material 103 is formed in a star shape. Patterning the region of the heat transfer material may reduce the lateral extent (lateral extent) of the heat transfer material 103, thereby improving the compliance (compliance) of the heat transfer material 103. This may help to prevent damage (e.g., tearing) to the heat transfer material 103 due to impact (e.g., when the device in which the actuator assembly 2 is incorporated falls).

In the illustrated embodiment, the actuator assembly 2 further comprises a support means 110, 120, 130. The support means 110, 120, 130 support the image sensor assembly 12 on the support structure 4 to form the gap 104. The support means 110, 120, 130 allow the image sensor assembly 12 to move relative to the support structure 4, for example in a manner that allows the image sensor assembly 12 to move relative to the support structure 4 in any direction transverse to the photosensitive region 7 and/or in a manner that allows the image sensor assembly 12 to rotate about any axis perpendicular to the photosensitive region 7.

As shown in fig. 2, 5 and 6, the support means may comprise a rolling support 110. The rolling bearing 110 may be, for example, a ball bearing, a roller bearing, or a rocker bearing. The rolling bearing 110 comprises rolling elements, such as balls, rollers or rocking elements. The rolling elements may be spherical or may generally be any rotating element having a curved surface against the image sensor assembly 12 and the support structure 4 and capable of rolling back and forth and around in operation.

The rolling elements are arranged between the image sensor assembly 12 and the support structure 4. Thus, the image sensor assembly 12 is supported on the support structure 4 by the rolling elements. The rolling bearing 110 may comprise a plurality of rolling elements, for example three rolling elements. Although any number of rolling elements may generally be provided, at least three rolling elements are preferably provided to prevent relative tilting of the image sensor assembly 12 and the support structure 4. Three rolling elements are sufficient to support the image sensor assembly 12 without tilting, and providing three rolling elements has the advantage of reducing the tolerance required to maintain point contact with each rolling element in a common plane.

In the embodiment of fig. 2 and 6, the rolling bearing 110 is disposed on the same side of the image sensor assembly 12 as the gap 104, as shown in fig. 2 and 6. This ensures that the height of the gap 104 remains constant even when a large force is applied to the image sensor assembly 12. The rolling bearing 110 may be arranged outside the gap 104, e.g. laterally to the gap 104, as shown in fig. 2. Thus, the extent of the rolling elements may be larger than the extent of the gaps 104 in a direction perpendicular to the photosensitive area 7. This may allow the height of the gap 104 to be reduced compared to the case where rolling elements are arranged in the gap 104.

Alternatively, as shown in fig. 6, the rolling bearing 110 may be disposed in the gap 104. This may reduce the lateral extent of the support device 110. The rolling elements may be incorporated into the heat transfer material 103 or may otherwise be arranged in the areas of the gap 104 where the heat transfer material 103 is not provided.

In an alternative embodiment, rolling bearing 110 is disposed on a side of image sensor assembly 12 opposite gap 104. The rolling bearing 110 is arranged on the same side of the image sensor assembly 12 as the photosensitive area 7, in particular laterally to the photosensitive area 7. This is schematically depicted in fig. 5. In such embodiments, the heat transfer material 103 disposed in the gap 104 may bias or help bias the image sensor assembly 12 against the rolling bearing 110.

The support means 110, 120, 130 may alternatively or additionally comprise flexing means 120, 130. Examples of flexing devices 120, 130 are schematically illustrated in fig. 7, 8, 9, and 10. The flexing means 120, 130 are arranged between the image sensor assembly 12 and the support structure 4. Thus, the image sensor assembly 12 is supported on the support structure 4 by the flexure devices 120, 130. The flexing means 120, 130 comprise a fixed portion 121, 131 fixed relative to the support structure 4 and a movable portion 122, 132 fixed relative to the image sensor assembly 12. The flexure means 120, 130 further comprise flexible elements 123, 133 arranged between the fixed portions 121, 131 and the movable portions 122, 132.

Typically, the image sensor assembly 12 is supported on the support structure 4 only by the flexures 120, 130, e.g., without any additional (sliding or ball) bearings. In general, in normal operation, the flexures 120, 130 constrain movement of the image sensor assembly 12 perpendicular to the plane in which the photosensitive region 7 extends.

Fig. 7 schematically depicts an example of a flexure device 120. The fixed part 121 of the flexure means is fixed to the support structure 4 or a member fixed relative to the support structure 4. The movable part 122 is fixed to the carrier 8, in particular to the moving plate 9. The flexible member 123 includes a beam 123 connected between the image sensor assembly 12 and the support structure. Fig. 7 shows four beams 123, however, generally any number of beams 123 may be provided, such as three or more beams 123. The beams 123 extend parallel to each other and to the optical axis O and thus perpendicular to the orthogonal direction of movement of the photosensitive region 7. The beams 123 may extend at angles other than perpendicular, so long as they are transverse to the orthogonal direction.

The beam 123 is fixed to each of the support structure 4 and the image sensor assembly 12 in such a way that the beam 123 cannot rotate (e.g., by welding). Thus, the beams 123 support the image sensor assembly 12 on the support structure 4 in the manner described, allowing the image sensor assembly 12 to move relative to the support structure 4 in two orthogonal directions perpendicular to the optical axis O simply by bending (in particular into an S-shape) the beams 123. Instead, the beam 123 resists movement along the optical axis O. The beams 123 may have any structure that provides the desired compliance perpendicular to the optical axis O, typically formed of wires (e.g., metal wires). The beams 123 may be mechanically connected to different corners of the image sensor assembly 12.

Fig. 8 schematically depicts an alternative example of a flexure device 120. In the example of fig. 8, the beam 123 includes a first portion 123a and a second portion 123b. Each beam 123 is formed in a U-shape, with a first portion 123a corresponding to one arm of the U-shape and a second portion corresponding to the other arm of the U-shape. The first portion 123a and the second portion 123b are parallel to each other and extend in a direction perpendicular to the photosensitive region 7. The first portion 123a and the second portion 123b are not collinear. The first portion 123a includes a movable portion 122, so the first portion 123a is connected to the image sensor assembly 12 at one end. The second portion 123b comprises a fixed portion 121, whereby the second portion 123b is connected at one end to the support structure 4. The other end of the first portion 123a and the other end of the second portion 123b are connected to each other.

The flexure 120 of fig. 8 allows the image sensor assembly 12 to move relative to the support structure 4 in a manner similar to the flexure 120 of fig. 7. The flexure device 120 of fig. 8 is more compact because the extent of the flexure device 120 in the direction along the axis O can be smaller in fig. 8 than in fig. 7. In fig. 8, the connection between the flexure 120 and the support structure 4 may be substantially in the same plane as the connection between the flexure 120 and the image sensor assembly 12.

The flexure device 120 of fig. 8 may be integrally formed. For example, the flexure 120 may be formed from sheet metal. The beam 123 may be formed by etching and bending a sheet metal.

The flexure device 120 of fig. 7 or 8 may also include a fall protection element. The fall protection element may inhibit buckling and thus avoid damaging the beam 123 due to sudden impact (e.g., when the device containing the actuator assembly 2 falls).

In general, in normal operation, the flexure device 120 constrains movement of the image sensor assembly 12 perpendicular to the plane in which the photosensitive region 7 extends. Optionally, the flexure device 120 is arranged to allow the image sensor assembly 12 to move perpendicular to the plane in which the photosensitive region 7 extends in the event of an impact, for example, caused by a drop event. The flexure means may help reduce friction between the moving part and the support structure. For example, friction may be lower than if sliding bearings were used.

For example, the movable portion 122 may be arranged as a fall protection element. In the event of an impact, any vertical forces are at least partially absorbed by the bending of the movable portion 122 (up or down in fig. 8). The movable part 122 is compliant in a direction perpendicular to the plane in which the photosensitive region 7 extends. By providing a fall protection element, the likelihood of the flexure device 120 being damaged in the event of an impact is reduced.

Optionally, the actuator assembly 2 comprises one or more end stops (not shown) configured to limit movement of the image sensor assembly 12 in a direction perpendicular to the plane in which the photosensitive region 7 extends. During an impact condition, the image sensor assembly 12 may be moved in a direction perpendicular to the plane in which the photosensitive region 7 extends until the image sensor assembly 12 abuts one or more end stops.

For example, the compliance of the movable portion 122 may be controlled by selecting the thickness, length, and material of the movable portion 122. Under normal conditions, the distance between the end stop and the image sensor assembly 12 may be selected to control how far the image sensor assembly 12 may move in the event of an impact. Optionally, end stops and fall protection elements such as movable portion 122 are arranged to enable image sensor assembly 12 to reach one or more end stops in the event of an impact. The likelihood of the flexure device 120 being overstressed in the event of an impact may be reduced.

Alternatively or additionally, at least one fall protection element may be provided by a portion similar to the movable portion 122 (e.g. horizontal portion of the beam 123) shown in fig. 8, but arranged between the fixed portion 121 of the beam 123 and the support structure 4.

Instead of extending to the edge of the image sensor assembly 12 at an angle of about 45 ° as shown in fig. 8, the beam 123 may extend at a different angle (when viewed in the direction of the optical axis O). For example, at least one beam 123 may extend in a direction parallel to the edge of image sensor assembly 12 (when viewed in a direction along optical axis O).

There may be any number of beams 123.

The flexure device 120 of fig. 7 or 8 may be used to provide electrical connection. Thus, the purpose of the flexure device 120 may be to provide electrical connections and to provide a bearing device that supports the image sensor assembly 12 on the support structure 4. The flexure device 120 may be configured to provide a drive signal (e.g., current) to the SMA actuator wire 40. The SMA actuator wire 40 may have a connection terminal at each end. Two or more of the SMA actuator wires 40 may share a common terminal. At least one terminal of each SMA actuator wire 40 is dedicated to the SMA actuator wire 40 (i.e., not common to the other wires). The flexure device 120 may be configured to provide a drive signal to one or more terminals (dedicated or common). Where the flexure 120 is configured to provide drive signals to a plurality of terminals, the flexure 120 may be electrically subdivided into a plurality of sections, each section including one or more beams 123 and insulated from the other sections. For example, each of the four beams 123 shown in fig. 8 may form part of a different such section. This may be accomplished by forming the flexure device 120 from separate components that are mechanically interconnected but not electrically interconnected.

In fig. 7 and 8, the actuator assembly 2 is a sensor displacement assembly. Alternatively, the actuator assembly 2 may be a lens displacement assembly, wherein the image sensor 6 is mounted to a stationary part of the actuator assembly 2 and the lens is part of a moving part of the actuator assembly 2. Such a lens displacement assembly may comprise an autofocus system. The moving part comprises an autofocus system. Optionally, the flexure device 120 is configured to transfer signals between the support structure 4 and the SMA actuator wires 40 and/or the autofocus system. For example, the flexure device 120 may transmit energy and/or control signals to an autofocus system. The flexure device 120 may communicate data from an autofocus system.

Fig. 9 and 10 schematically depict further examples of the flexure device 130. Flexure 130 includes flexible sheet 130. Flexible sheet 130 includes two first arms 124. The flexible sheet also includes one second arm 125 (as in fig. 9) or two second arms 125 (as in fig. 10). Each of the first arm 124 and the second arm 125 extends in a direction perpendicular to the photosensitive region 7. The first arms 124 are parallel and face each other, and the second arms 125 are parallel and face each other. The first arm 124 is perpendicular to the second arm 125. Each first arm 124 may include a rigid portion 124a, such as a rigid plate, fixedly attached to the image sensor assembly 12. Each first arm 124 may also include a flexible portion 124b, the flexible portion 124b extending from the rigid portion 124a to a respective connection with one or both second arms 125. Each second arm 125 may comprise a rigid portion 125a, such as a rigid plate, fixedly connected to the support structure 4. Each second arm 125 may also include a flexible portion 125b, the flexible portion 125b extending from the rigid portion 125a to a respective connection with the two first arms 125. The connection between the first arm 124 and the second arm 125 may be a rigid connection (such that the angle between the first arm 124 and the second arm 125 remains unchanged) or a flexible connection, such as a hinged connection.

The flexure 130 of fig. 9 is located on one side of the image sensor assembly 12. The flexure of fig. 10 surrounds the image sensor assembly 12. The flexure arrangement of fig. 10 may provide more stable support of the image sensor assembly 12 on the support structure 4.

Fig. 10a and 10b schematically depict in plan view the movement allowed by the flexing device 120 of fig. 10. Although not shown, the movement allowed by the flexing means 120 of FIG. 9 is similar. The dashed lines in fig. 10a and 10b depict the position of the flexible sheet 120 before the movement of the image sensor assembly 12, and the solid lines depict the position of the flexible sheet 120 after the movement of the image sensor assembly 12 in the direction of the arrow in fig. 10a and 10 b. In particular, the flexible portion 125b of the second arm 125 may deform when the image sensor assembly 12 is moved in a direction parallel to the first arm 124. The first arm 124 may also be deformed if the joint between the first and second arms 124, 125 is rigid. If the joint between the first arm 124 and the second arm 125 is flexible (e.g., a hinge), the first arm may maintain the shape of the first arm. Conversely, when moving the image sensor assembly 12 in a direction parallel to the second arm 124, the flexible portion 124b of the first arm 124 may deform to allow the image sensor assembly 12 to move. The second arm 125 may also be deformed if the joint between the first arm 124 and the second arm 125 is rigid. If the joint between the first arm 124 and the second arm 125 is flexible (e.g., a hinge), the second arm 125 may maintain the shape of the second arm 125.

The flexible sheet 120 may include at least two flexible printed circuits. The flexible printed circuit is electrically connected to the image sensor assembly. Thus, the purpose of the flexible sheet 120 may be to provide electrical connection to the image sensor assembly, as well as to provide a bearing means to support the image sensor assembly 12 on the support structure 4.

Alternatively, the flexible sheet 120 may be configured to provide a drive signal (e.g., current) to the SMA actuator wire 40. The flexible sheet 120 may be configured to transfer signals between the support structure 4 and the image sensor 6. For example, the flexing device 120 can transmit energy and/or control signals to the image sensor 6. The flexing means 120 can transfer data, such as image data from the image sensor 6.

In fig. 9 and 10, the actuator assembly 2 is a sensor displacement assembly. Alternatively, the actuator assembly 2 may be a lens displacement assembly, wherein the image sensor 6 is mounted to a stationary part of the actuator assembly 2 and the lens is part of a moving part of the actuator assembly 2. Such a lens displacement assembly may comprise an autofocus system. The moving part comprises an autofocus system. Optionally, the flexible sheet 120 is configured to transfer signals between the support structure 4 and the SMA actuator wires 40 and/or the autofocus system. For example, the flexible sheet 120 may transmit energy and/or control signals to an autofocus system. The flexible sheet 120 may communicate data from an autofocus system.

Alternatively or additionally, the support means 110, 120, 130 may comprise a heat transfer material 103. The heat transfer material 103 may be selected to allow the image sensor assembly 12 to be supported on a support structure. The heat transfer material 103 may be, for example, silicone rubber or other rubber. In some cases, some degree of tilt and/or movement along the optical axis O may be tolerated, and thus the use of the above-described support devices 110, 120, 130 may not be required.

Alternatively or additionally, the support means 110, 120, 130 may comprise a sliding support, such as a structured sliding support. The sliding bearing comprises bearing surfaces on each of the image sensor assembly 12 and the support structure 4. The bearing surfaces may each be planar. The bearing surfaces bear against each other to support the image sensor assembly 12 on the support structure 4, allowing relative sliding movement. The sliding support thus allows the movement of the image sensor assembly 12 relative to the support structure 4, in particular in the manner described which allows the movement or rotation of the image sensor assembly 12 relative to the support structure 4 in any direction transverse to the photosensitive region 7.

The sliding bearing may be configured to reduce the contact area of the bearing surface, thereby reducing friction between the image sensor assembly 12 and the support structure 4 and forming the gap 104. A sliding bearing may be provided in the selection area, and a gap 104 may be formed between the selection areas in which the sliding bearing is provided. The total contact area of the bearing surfaces forming the sliding bearing may be less than 1, preferably less than 0.5, further preferably less than 0.2, particularly preferably less than 0.1 of the area of the photosensitive area 7. With respect to friction reduction, the bearing surface may be designed to have a coefficient of friction of 0.2 or less.

Furthermore, the actuator assembly 2 may comprise biasing means. The biasing device may provide a biasing force that biases image sensor assembly 12 toward support device 110. An example of a biasing means is schematically depicted in fig. 3. Fig. 3 shows two flexures 67 connected between support structure 4 and carrier 8/moving plate 9 to act as biasing means and to provide electrical connection to image sensor assembly 12. In this example, the flexure 67 is integrally formed with the moving plate 9 at one end 68 thereof and is mounted to the support plate 5 of the support structure 4 at the other end 69 thereof. Alternatively, the flexure 67 may be integrally formed with the plate of the support structure 4 and mounted to the carrier 8, or alternatively may be a separate element mounted to each of the support structure 4 and the carrier 8. In any of these examples, the mounting of the flexure 67 may be accomplished, for example, by welding that provides both mechanical and electrical connections.

The flexures 67 are arranged to provide their mechanical function as follows. Each flexure 67 is an elongated beam connected between the support structure 4 and the carrier 8. The flexure 67 biases the support structure 4 and the image sensor assembly 12 together due to its inherent resilience, the biasing force being applied parallel to the optical axis O. This may hold the support device 110, such as the support device of fig. 2, 5 or 6. At the same time, the flexure 67 may deflect laterally to allow the image sensor assembly 12 to move and rotate laterally relative to the support structure 4, allowing OIS functionality.

Also due to its inherent resiliency, the flexure 67 also provides a lateral biasing force that biases the image sensor assembly 12 toward a central location aligned with the optical axis O of the lens assembly 20 from any direction about that central location. As a result, without driving the SMA wire 40, the image sensor assembly 12 will tend to a centered position. This ensures that the camera device 1 retains the function of capturing images even without driving the SMA wire 40.

The flexure 67 is designed as follows to provide a suitable holding force for the support device 110 along the optical axis O and also to allow lateral movement with lateral biasing forces. The magnitude of the lateral biasing force remains low enough so as not to interfere with OIS, while being high enough to center the image sensor assembly 12 without actuation. Each flexure 67 has a cross-section with an average width orthogonal to the optical axis O that is greater than its average thickness parallel to the optical axis O. Each flexure 67 extends in an L-shape about the optical axis O, with the angular range generally desirably being at least 90 degrees as measured between the ends of the flexures 67.

In the assembled state of the actuator assembly 2, the flexure 67 deflects from its relaxed state to provide a preload force that biases the support structure 4 and the image sensor assembly 12 together.

The flexure 67 is made of a suitable material that provides the desired mechanical properties and is electrically conductive. Typically, the material is a metal, e.g., steel such as stainless steel, having a relatively high yield strength.

Alternatively or additionally, the biasing means may comprise a heat transfer material 103. The heat transfer material 103 may be selected such that it is capable of applying a biasing force to the image sensor assembly 12, such as when used in conjunction with the support apparatus 110 of fig. 5. The heat transfer material 103 may also provide or contribute to a lateral biasing force that biases the image sensor assembly 12 toward a central position.

The movement of the image sensor assembly 12 relative to the support structure 4 is driven by a transverse actuator device arranged as follows and is most easily seen in fig. 4. A particular advantage is achieved in the case of an actuator device comprising a plurality of SMA wires 40, since SMA provides a high actuation force compared to other forms of actuator. This may facilitate accurate positioning of the image sensor assembly 12 relative to the support structure 4. In general, however, the actuator arrangement may comprise a plurality of actuator members other than SMA wires 40.

The lateral actuator device shown in fig. 4 is formed by a total of four SMA wires 40 connected between the support structure 4 and the carrier 8. For attaching the SMA wire 40, the carrier 8 comprises a crimp portion 41 fixed to the moving plate 9 and the support structure 4 comprises a crimp portion 42 fixed to the border portion 10. The crimp portions 41 and 42 crimp the four SMA wires 40 to connect them to the support structure 4 and the carrier 8. The crimp portions 41 fixed to the moving plate 9 are integrally formed from sheet metal so as to electrically connect the SMA wires 40 together at the carrier 8.

Although the crimping portions 41 and 42 are separate elements fixed to the moving plate 9 and the boundary portion 10 in this example, the crimping portion 41 may be integrally formed with the moving plate 9 and/or the crimping portion 42 may be integrally formed with the support plate 5 as an alternative.

Fig. 15 is a cross-sectional view of the actuator assembly 2. The actuator assembly 2 comprises an image sensor assembly 12, the image sensor assembly 12 being movable relative to the support structure 4. The image sensor assembly comprises a moving plate 9 (which may also be referred to as an end stop plate, as described in more detail below) and an image sensor 6 comprising a photosensitive area 7. The support structure 4 comprises a casing (can) 15, a substrate 51 and a conductor layer 52. The housing 15 may include a support plate 5.

The image sensor assembly 12 is supported on the support structure 4 such that a gap 104 is formed between the image sensor assembly 12 and the support structure 4. The gap 104 is formed on the side of the image sensor component 12 facing away from the photosensitive region 7, in particular in a direction perpendicular to the photosensitive region 7. The gap 104 is formed in particular between the moving plate 9 and the support plate 5, which support plate 5 may be part of the housing 15.

The actuator assembly 2 comprises a support 110, which may be a rolling support or a sliding support, for example. The support 110 is disposed on a side of the image sensor assembly 12 opposite the gap 104. The support 110 is arranged on the same side of the image sensor assembly 12 as the photosensitive area 7, in particular laterally to the photosensitive area 7.

As shown in fig. 15, the support structure 4 optionally comprises a support layer 51 (which may also be referred to as a footbed). The support layer 51 is configured to provide mechanical support to the actuator assembly 2. The support layer 51 may surround holes allowing light to reach the image sensor 6. The support layer 51 may be shaped to form a boundary of the top edge of the support structure 4. The support layer 51 may comprise a hard material, such as a metal. The support layer 51 may be formed as a separate member from the remainder of the casing 15 and then attached (e.g., glued or welded) to the remainder of the casing 15. Alternatively, the support layer 51 may be integral with the housing 15.

As shown in fig. 15, the support structure 4 optionally includes a conductor layer 52. The conductor layer 52 includes one or more electrical tracks configured to transmit signals to and/or from the actuator. For example, the conductor layer 52 may include tracks for transmitting power and/or control signals to drive SMA actuator wires. The conductor layer 52 may include one or more tracks that communicate data about the SMA actuator wires to the actuator assembly 2 or the controller of the camera device 1.

As shown in fig. 15, the conductor layer 52 is optionally fixed relative to the housing 15. For example, the conductor layer 52 may be attached to the support layer 51. The conductor layer 52 may be located between the support layer 51 and the image sensor assembly 12. The conductor layer 52 is arranged so as not to increase the depth of the actuator assembly 2. The conductor layer 52 may surround holes allowing light to reach the image sensor 6. The conductor layer 52 may be shaped as a border on the underside of the support layer 51 of the support structure 4.

As shown in fig. 15, optionally, one end 68 of the flexure 67 is fixed (e.g., glued or welded) to the moving plate 9. Alternatively, the end 68 of the flexure 67 may be integral with the moving plate 9. The other end 69 of the flexure 67 (not shown in fig. 15) is attached to the support structure 4. As shown in fig. 15, the end 68 of the flexure 67 may be located between the conductor layer 52 or the support layer 51 and the moving plate 9.

As shown in fig. 15, optionally, a support 110 is located between the conductor layer 52 and the end 68 of the flexure 67. The support 110 may run over the ends 68 of the flexures 67 and the conductor layer 52. The support 110 abuts the surface of the conductor layer 52. The support abuts the surface of the end 68 of the flexure 67.

The diameter of the support 110 may be at least 30% and optionally at least 40% of the height of the actuator assembly 2. As shown in fig. 15, the height of the actuator assembly is the distance in the vertical direction between the top side of the support layer 51 and the bottom side of the support plate 5 of the housing 15. It is desirable to reduce the height of the actuator assembly 2.

A gap 55 is provided between the parts of the actuator assembly 2 that move relative to each other. A gap 55 may be defined between an end 68 of the flexure 67 and the conductor layer 52 (or housing 56 shown in fig. 18 and described below). The gap may be at least 20 μm, alternatively at least 50 μm, and alternatively at least 100 μm. The gap 55 may be large enough to account for small amounts of bending of the plates of the actuator assembly 2. The gap 55 reduces the likelihood that members intended to move relative to each other will come into contact with each other. Any such contact undesirably creates mechanical interference and potential electrical shorting.

Fig. 16 is a cross-sectional view of the actuator assembly 2. The actuator assembly 2 shown in fig. 16 has a smaller height than the actuator assembly 2 shown in fig. 15. Common features between the actuator assembly 2 of fig. 16 and the actuator assembly 2 of fig. 15 are not described in detail below. Instead, the description focuses on the differences between the actuator assembly 2 of fig. 16 and the actuator assembly 2 shown in fig. 15.

As shown in fig. 16, alternatively, the components may be pulled closer (relative to the actuator assembly 2 shown in fig. 15) by running the support 110 over the support layer 51 and the moving plate 9. As shown in fig. 16, holes may optionally be provided in the conductor layer 52 to accommodate each support 110. The support 110 is positioned in the hole such that the support 110 abuts the support layer 51. By providing holes (which may also be referred to as cutouts), the height of the actuator assembly 2 reduces the thickness of the conductor layer 52. The thickness of the conductor layer 52 may be at least 50 μm, and optionally at least 100 μm. The thickness of the conductor layer 52 may be at most 200 μm and optionally at most 100 μm.

As shown in fig. 16, holes are optionally provided in the end 68 of the flexure 67 fixed to the moving plate 9 to accommodate each support 110. The support 110 is positioned in the hole such that the support 110 abuts the moving plate 9. By providing a hole (which may also be referred to as a cutout), the height of the actuator assembly 2 reduces the thickness of the material forming the flexure 67. The thickness of the material forming the flexure 67 may be at least 50 μm, and optionally at least 100 μm. The thickness of the material forming the flexure 67 may be at most 200 μm, and optionally may be at most 150 μm.

By providing holes in the ends 68 of the flexures 67, the flexures 67 extend a short distance in the height direction. The distance of the two ends 68, 69 of the flexure 67 in the direction perpendicular to the photosensitive region 7 of the image sensor 6 decreases. This may reduce the force exerted by the flexure 67 between the support structure 4 and the image sensor assembly 12. Alternatively, the flexure 67 may be shaped during manufacture of the actuator assembly 2 to provide additional biasing force to compensate for the reduced distance. Optionally, the flexure 67 is formed into a particular shape prior to assembly of the actuator assembly 2 (i.e., prior to assembly of the image sensor assembly 12 with the support plate 5). For example, the flexure 67 may include a bend (jog).

The actuator assembly 2 shown in fig. 16 has holes in both the conductor layer 52 and the ends 68 of the flexures 67. Alternatively, such holes may be provided in only one of the conductor layer 52 and the end 68 of the flexure 67.

Fig. 17 is a cross-sectional view of the actuator assembly 2. The actuator assembly 2 shown in fig. 17 has a smaller height than the actuator assembly 2 shown in fig. 15 or the actuator assembly 2 shown in fig. 16. Common features between the actuator assembly 2 of fig. 17 and the actuator assembly 2 of fig. 15 are not described in detail below. Instead, the description focuses on the differences between the actuator assembly 2 of fig. 17 and the actuator assembly 2 shown in fig. 15.

As shown in fig. 17, holes are provided in both the conductor layer 52 and the ends 68 of the flexures 67 to accommodate the support 110. As shown in fig. 17, the moving plate 9 may alternatively be divided into two plates including a support plate 53 (which may also be called a bracket) for the operation of the support 110 and a receiving plate 54 for receiving the support 110. Alternatively, a half-etched single plate may be used as the moving plate 9 (i.e., the support plate 53 and the accommodation plate 54 may be integral).

As shown in fig. 17, holes are optionally provided in the receiving plate 54 to receive each support 110. The support 110 is positioned in the hole such that the support 110 abuts the support plate 53. This may help reduce the height of the actuator assembly 2 by a small portion of the thickness of the moving plate 9.

The thickness of the moving plate 9 may be at least 50 μm, and optionally at least 100 μm. The thickness of the moving plate 9 may be at most 200 μm and optionally at most 150 μm. The height of the actuator assembly 2 may reduce the difference between the thickness of the moving plate 9 and the thickness of the support plate 53 (relative to the height of the actuator assembly 2 shown in fig. 16). The thickness of the support plate 53 may be at least 20 μm, and optionally at least 50 μm. The thickness of the support plate 53 may be at most 100 μm and optionally at most 50 μm. The difference between the thickness of the moving plate 9 and the thickness of the support plate 53 may be at least 50 μm, and optionally at least 100 μm.

The actuator assembly 2 shown in fig. 17 has holes in both the conductor layer 52, except for the holes in the end 68 of the flexure 67 and the receiving plate 53. Alternatively, such holes may be provided in the end 68 of the flexure 67 and the containment plate 53, but not in the conductor layer 52.

Although not shown in the drawings, the principle described above as applied to the moving plate 9 may be additionally or alternatively applied to the support layer 51. Alternatively, the support layer 51 may be divided into two plates including a support plate for the operation of the support 110 and a receiving plate for receiving the support 110. Alternatively, a half-etched veneer may be used as the support layer 51 (i.e., the support plate and the accommodating plate may be integral).

Optionally, holes are provided in the receiving plate of the support layer 51 to receive each support 110. The support 110 is positioned in the hole such that the support 110 abuts the support plate of the support layer 51. This may help reduce the height of the actuator assembly 2 by a small fraction of the thickness of the support layer 51.

The thickness of the support layer 51 may be at least 50 μm, and optionally at least 100 μm. The thickness of the support layer 51 may be at most 200 μm and optionally at most 150 μm. The height of the actuator assembly 2 may be reduced (relative to the height of the actuator assembly 2 shown in fig. 16 or 17) by the difference between the thickness of the support layer 51 and the thickness of the support plate of the support layer 51. The thickness of the support plate of the support layer 51 may be at least 20 μm, and optionally at least 50 μm. The thickness of the support plate of the support layer 51 may be at most 100 μm and optionally at most 50 μm. The difference between the thickness of the support layer 51 and the thickness of the support plate of the support layer 51 may be at least 50 μm, and optionally at least 100 μm.

Fig. 18 is another cross-sectional view of the actuator assembly 2 of fig. 15. Fig. 18 shows more details, in particular about the function of the crimp portion 41 and the moving plate 9 as end stops. Fig. 18 is a cross-sectional view taken along a different line of the actuator assembly 2. The cross section shown in fig. 15 (and also fig. 16 and 17) extends across the entire width of the actuator assembly and through the image sensor 6, but not through any crimp portions 41, 42. The cross section shown in fig. 18 extends only partially through the actuator assembly 2 and through the arms secured to the crimp portion 41 and the flexure 67 of the image sensor assembly 12.

The features shown and described in relation to fig. 18 may equally be applied to the actuator assembly 2 shown in fig. 16 or the actuator assembly 2 shown in fig. 17. As shown in fig. 18, the actuator assembly 2 optionally includes a housing 56. The housing 56 is configured to house a support 110. The housing 56 is configured to constrain movement of the support 110. The housing 56 may be shaped as a plate provided with holes to accommodate the support 110. The housing 56 may be part of the support structure 4. The housing 56 may be secured (e.g., glued or welded) to the conductor layer 52. Such a housing 56 may be provided in the actuator assembly 2 shown in fig. 16, albeit with a smaller thickness (as there is less available space and the holes in the conductor layer 52 effectively function like the housing 56). The provision of the housing 56 is not necessary. For example, holes in the conductor layer 52 may substantially constrain the support 110.

As shown in fig. 18, the actuator assembly 2 optionally includes a crimp spacer 57. The crimp spacer 57 is arranged to connect the crimp portion 41 to the moving plate 9. The crimp spacer may be secured (e.g., welded) to the end 68 of the flexure 67. Crimp spacer 57 may connect crimp portion 41 to end 68 of flexure 67. The provision of crimp spacers 57 is not necessary. Alternatively, the crimping portion 41 may be directly connected to the end 68 of the flexure 67 or the moving plate 9. As shown in fig. 18, holes are optionally provided in the moving plate to accommodate each crimp spacer 57.

Each aperture that accommodates a support 110 may be sized such that the diameter of the support 110 is at least half, alternatively at least 80%, and alternatively at least 90% of the diameter of the aperture.

As shown in fig. 18, the moving plate 9 is optionally arranged such that a gap 58 exists between the edge of the moving plate 9 and the inner surface of the casing 15. During use of the actuator assembly 2, the moving plate 9 moves relative to the housing 15. This movement causes the gap 58 to increase or decrease in size. Alternatively, the moving plate 9 is configured to function as an end stop. When the moving plate 9 moves such that the gap 58 becomes zero and the moving plate 9 abuts the casing 15, further movement of the image sensor assembly 12 relative to the support structure 4 in that direction is prevented. This may help reduce the likelihood of damage to the SMA actuator wires due to the image sensor assembly 12 moving too far in a particular direction relative to the support structure 4. Providing an end stop within the actuator assembly 2 may also facilitate testing of the actuator prior to incorporating the image sensor 6 into the actuator assembly 2. This, in turn, may help reduce the likelihood that the image sensor will be discarded along with the actuator that failed the test procedure, thereby reducing the average cost of manufacturing the actuator assembly 2. This is in contrast to, for example, a comparative example in which such an end stopper includes a separate member, such as a housing, which must be bonded after the image sensor 6. The same principle can be applied to end stops (not shown) that limit movement in other directions, for example along the optical axis O.

In fig. 15-18, the actuator assembly 2 is a sensor displacement assembly. Alternatively, the actuator assembly 2 may be a lens displacement assembly, wherein the image sensor 6 is mounted to a stationary part of the actuator assembly 2 and the lens is part of a moving part of the actuator assembly 2. Features associated with the support 110 extending through one or more components of the actuator assembly 2 to reduce the height of the actuator assembly 2 may be applied to such a lens displacement assembly.

In fig. 15-18, a support 110 is provided on the opposite side of the image sensor assembly 12 from the gap 104. Alternatively, the support 110 may be disposed on the same side of the image sensor assembly 12 as the gap 104.

Fig. 19 is a perspective view of the support impact protection structure 60. The supporting impact protection structure 60 may be incorporated as part of any arrangement of the actuator assembly 2 described elsewhere in this document. Fig. 19 shows a carrier 8 comprising an actuator assembly 2 supporting an impact protection structure 60. The actuator assembly 2 may be a sensor displacement assembly. The supporting impact protection structure 60 may be included in an image sensor assembly 12 that moves relative to the support structure 4. Alternatively, the bearing impact protection structure 60 may be comprised in the support structure 4 of the sensor displacement assembly. As a further alternative, the supporting impact protection structure 60 may be included in the moving part of the lens displacement assembly.

Impact protection is provided by cantilever arms 61 cut into the plate. In the arrangement shown in fig. 19, the cantilever 61 is cut into the plate of the carrier 8. The carrier 8 may be part of a sensor displacement assembly. The plate of the carrier 8 comprising the cantilever 61 may be formed from sheet metal. One or more shaped cutouts 62 form cantilever arms 61 in portions of the plate. Fig. 19 shows three such cantilevers 61, but there may be more cantilevers 61, e.g. four cantilevers. Each cantilever 61 supports a bearing 110 at its free end 63, the bearing 110 may be a ball bearing. For clarity, one or more of the supports 110 in fig. 19 are shown in exploded view, with dashed lines indicating their positions.

In normal operation, the support 110 is free to move laterally over the area at the free end 63 of the cantilever 61. In the event of an impact, any vertical forces are absorbed by the bending of the free end 63 of the cantilever 61 (downwards in fig. 19). The supporting impact protection structure 60 may be formed as a single piece of cut metal that is easy to manufacture and assemble to other components.

The plate provided with the cantilever 61 may be a plate forming a surface with which the support 110 contacts. For example, the cantilever 61 may be provided in the peripheral portion of the moving plate 9 shown in fig. 2 laterally to the gap 104. The cantilever 61 may be provided in the moving plate 9 shown in any one of fig. 5 to 8. The cantilever 61 may be disposed in an end 68 of the flexure 67 shown in fig. 15. A hole may be provided in the moving plate 9 adjacent to each cantilever 61 to allow the cantilever 61 to flex into the hole away from the support 110. The cantilever 61 may be provided in the moving plate 9 shown in fig. 16. The cantilever 61 may be provided in the support plate 53 shown in fig. 17.

As mentioned above, the cantilever 61 may alternatively be provided in a plate of the support structure 4. For example, the cantilever 61 may be provided in the support plate 5 shown in fig. 2. The cantilever 61 may be provided in any of the arrangements of support structures 4 shown in figures 5 to 8. The cantilever 61 may be disposed in the conductor layer 52 shown in fig. 15. A hole may be provided in the support layer 51 adjacent to each cantilever 61 to allow the cantilever 61 to flex away from the support 110 into the hole. The cantilever 61 may be provided in the support layer 51 shown in fig. 16 or 17.

For example, the cantilever 61 is arranged to deflect during a drop event. The support impact protection structure 60 is configured to reduce the likelihood of damage to the support 110 and/or the support surface. The deflection of the cantilever arm 61 dissipates energy, thereby reducing the energy that might otherwise damage the actuator assembly 2 during a drop event.

Fig. 20 is a perspective view of a portion of image sensor assembly 12 with support member 110 received. Fig. 20 shows a subassembly comprising the supporting impact protection structure 60 of fig. 19. In fig. 20, a cantilever 61 is provided in the moving plate 9 of the image sensor assembly 12 of the sensor displacement actuator. In fig. 20, the support and holding structure 64 is shown assembled on top of the moving plate 9 containing the cantilever 61. The support retaining structure 64 is shown as a relatively thick plate with holes 65 for locating the support 110.

Another impact protection structure in the form of an end stop 66 is also shown in fig. 20. Four end stops 66 are shown, but there may be more or fewer end stops. For example, three end stops 66 may be used. Each end stop 66 may be a pad of material that protrudes above the body but is lower in height than the support 110. The relative heights of the support 110, end stop 66, and body of the support retention structure 64 are shown in fig. 21. Fig. 21 is a cross-sectional view of the subassembly shown in fig. 20.

In normal operation, the end stop 66 is not functional, but in the event of an impact, the end stop 66 prevents the bearing surface of the support structure 4 (not shown, but generally at the level of the top of the support 110) from moving farther down than the top of the end stop 66. Thus, under the action of the vertical impact force, the cantilever 61 absorbs a part of the downward movement by deflection, and the end stopper 66 restricts the further movement. The end stop 66 may be arranged to limit the vertical movement of the support structure 4 relative to the carrier 8. The end stop 66 may be a simple pad of material and is easily assembled or mounted to the top of the support and retaining structure 64.

In the arrangement shown in fig. 20, the end stop 66 is included in the moving part of the actuator assembly 2. The end stop 66 protrudes towards the support structure 4 and is arranged to abut the support structure 4 only during a fall event, for example. Alternatively, the end stop 66 may be included in the support structure 4 and may protrude toward the image sensor assembly 12. The end stop 66 may be arranged with a gap between the end stop 66 and the image sensor assembly 12. For example, the end stop 66 may be arranged to abut the image sensor assembly 12 only during a fall event.

It is not necessary to provide a supporting retaining structure 64. Alternatively, the end stop 66 may protrude from the moving plate 9 towards the support structure 4. Alternatively, the end stops 66 may protrude from the ends 68 of the flexures 67 toward the support structure 4, or from the conductor layer 52 toward the image sensor assembly 12, or from the support layer 51 toward the image sensor assembly 12, or from the housing 56 toward the image sensor assembly 12. In other examples, the cantilever 61 may be formed as a separate element and attached to the plate, rather than by a cutout in a particular plate.

The SMA wires 40 are arranged such that the SMA wires 40, when selectively driven, are capable of moving the image sensor assembly 12 relative to the support structure 4 in any direction transverse to the photosensitive region 7, and are also capable of rotating the image sensor assembly 12 about an axis orthogonal to the photosensitive region 7.

Each SMA wire 40 is held in tension, thereby exerting a force between the support structure 4 and the carrier 8.

The SMA wire 40 may be perpendicular to the optical axis O such that the force applied to the carrier 8 is transverse to the photosensitive region 7. Alternatively, the SMA wire 40 may be inclined at a small angle relative to the photosensitive region 7 such that the force applied to the carrier 8 comprises a component transverse to the photosensitive region 7 and a component along the optical axis O that acts as a biasing force biasing the image sensor assembly 12 against the support means 110. Thus, the SMA wire 40 may act as a biasing device. The biasing means may comprise a plurality of actuator members inclined with respect to the photosensitive area 7 for applying a biasing force biasing the image sensor assembly 12 towards the support means 110, 120, 130.

The general arrangement of SMA wires 40 similar to that described in WO-2014/083318 will now be described, except that the SMA wires move the image sensor assembly 12 rather than the lens assembly 20.

SMA materials have the property of undergoing a solid state phase change upon heating, which causes the SMA material to contract. At low temperatures, the SMA material enters the martensite phase. At high temperatures, the SMA enters the austenitic phase, which induces deformation, resulting in contraction of the SMA material. The phase change occurs over a range of temperatures due to the statistical distribution of the transformation temperatures in the SMA crystal structure. Thus, heating of the SMA wire 40 results in a reduction in the length of the SMA wire 40.

The SMA wire 40 may be made of any suitable SMA material (e.g., nitinol or another titanium alloy SMA material). Advantageously, the material composition and pretreatment of the SMA wire 40 is selected to provide phase transformation during normal operation over a temperature range above the expected ambient temperature and as wide as possible to maximize the degree of positional control.

Upon heating one of the SMA wires 40, the stress therein increases and the SMA wire 40 contracts, causing movement of the image sensor assembly 12. When the temperature of the SMA increases above the temperature range in which the transformation of the SMA material from the martensite phase to the austenite phase occurs, a range of movement occurs. Conversely, when one of the SMA wires 40 is cooled to reduce the stress therein, that SMA wire 40 expands under the force of the opposing one of the SMA wires 40. This causes the image sensor assembly 12 to move in the opposite direction.

The carrier 8 and the image sensor assembly 12 are axially positioned within the aperture 11 of the border portion 10 of the support structure 4. Four SMA wires 40 are arranged on four sides of the image sensor assembly 12. The SMA wires 40 have the same length and have a rotationally symmetrical arrangement.

Seen in the axial direction, the first pair of SMA wires 40 extends parallel to a first axis (in fig. 4 the vertical axis) transverse to the photosensitive region 7. However, the first pair of SMA wires 40 are oppositely connected to the support structure 4 and the carrier 8 such that they apply forces in opposite directions (vertically upwards and downwards in fig. 4) along the first axis. With equal tension in each SMA wire 40, the forces applied by the first pair of SMA wires 40 are balanced. This means that the first pair of SMA wires 40 applies a first torque (counterclockwise in fig. 4) to the image sensor assembly 12.

The second pair of SMA wires 40 extends parallel to a second axis (horizontal axis in fig. 4) transverse to the photosensitive region 7, as seen in an axial direction. However, the second pair of SMA wires 40 are oppositely connected to the support structure 4 and the carrier 8 such that they apply forces in opposite directions (horizontally to the left and right in fig. 4) along the second axis. With equal tension in each SMA wire 40, the forces applied by the second pair of SMA wires 40 are balanced. This means that the second pair of SMA wires 40 applies a second torque (clockwise in fig. 3) to the image sensor assembly 12 that is arranged to be opposite in direction to the first torque. Thus, the first torque and the second torque balance with the same tension in each SMA wire 40.

As a result, the SMA wire 40 may be selectively actuated to move the image sensor assembly 12 laterally in any direction and to rotate the image sensor assembly 12 about an axis parallel to the optical axis O. Namely:

● Movement of the image sensor assembly 12 in either direction along the first axis may be achieved by driving the first pair of SMA wires 40 to contract differentially, as they exert forces in opposite directions;

● Movement of the image sensor assembly 12 in either direction along the second axis may be achieved by driving the second pair of SMA wires 40 to contract differentially, as they exert forces in opposite directions; and

● Rotation of the image sensor assembly 12 may be achieved by driving the first and second pairs of SMA wires 40 to contract differently, as the first and second torques are in opposite directions.

The magnitude of the range of movement and rotation depends on the geometry and contraction range of the SMA wire 40 within its normal operating parameters.

This particular arrangement of SMA wires 40 is advantageous because it can drive the desired lateral movement and rotation with a minimum number of SMA wires. However, other arrangements of SMA wires 40 may be applied. To provide three degrees of motion (two lateral degrees of motion and one rotational degree of motion), a minimum of four SMA wires 40 are provided. Other arrangements may employ a different number of SMA wires 40. For lateral movement (but not rotation), fewer SMA wires 40 may be provided. Arrangements with more than four SMA wires 40 are also possible and may have advantages in allowing additional parameters (e.g., the degree of stress in the SMA wires 40) to be controlled in addition to motion.

The lateral position and orientation of the image sensor assembly 12 relative to the support structure 4 is controlled by selectively varying the temperature of the SMA wires 40. This actuation of the SMA wire 40 is achieved by passing a selective actuation signal through the SMA wire 40 to provide resistive heating. The current through the drive signal directly provides heating. Cooling is provided by reducing or stopping the current of the drive signal to allow the SMA wire 40 to cool by conduction, convection and radiation from its surroundings.

The camera device 1 comprises a lens assembly 20, which lens assembly 20 is assembled with the actuator assembly 2 by being mounted to the support structure 4, in particular to the border portion 10.

The lens assembly 20 comprises a lens carrier 21 in the form of a cylindrical body which is mounted to the border portion 10 of the support structure 4. The lens carrier supports at least one lens arranged along an optical axis O. In general, any number of one or more lenses 22 may be provided. Without limiting the invention, in this example the camera device 1 is a miniature camera, wherein at least one lens 22 (i.e. each lens 22 if a plurality of lenses are provided) typically has a diameter of at most 10mm or 15mm or 20 mm. At least one lens 22 of the lens assembly 20 is arranged to focus an image onto the image sensor.

In this example, the at least one lens 22 is supported on the lens carrier 21 in such a way that the at least one lens 22 is movable along the optical axis O with respect to the lens carrier 21, for example to provide focusing or zooming, although this is not required. Specifically, at least one lens 22 is fixed to a lens holder 23 movable along the optical axis O with respect to the lens carrier 21. In case there are a plurality of lenses 22, any or all of the lenses 22 may be fixed to the lens holder 23 and/or one or more lenses 22 may be fixed to the lens carrier 21 and thus not movable along the optical axis O with respect to the lens carrier 21.

The axial actuator means 24 arranged between the lens holder 21 and the lens holder 23 is arranged to drive the lens holder 21 and the lens 22 along the optical axis O relative to the lens holder 21. The axial actuator device 24 may be of any suitable type, for example a Voice Coil Motor (VCM) or SMA wire device, as described in WO-2019/243849, WO-2019/243849 being incorporated herein by reference.

In addition, the camera apparatus 1 may include a cover case 15 fixed to the support structure 4 and protruding forward from the support structure 4 to encase and protect other components of the camera apparatus 1.

As described above, in operation, the SMA wire 40 is selectively driven to move the image sensor assembly 12 laterally in any direction and/or to rotate the image sensor assembly 12 about an axis parallel to the optical axis O. This is used to provide OIS compensating for image movement of the camera device 1 caused by, for example, hand trembling.

The relative movement of the image sensor with respect to the support structure 4 and thus also with respect to the lens assembly 20 may be used to stabilize the image against tilting of the camera device 1 (i.e. rotation about an axis extending transversely to the photosensitive area 7). Which occurs in a manner similar to that disclosed in WO-2013/175197 and WO-2014/083318 which provides OIS-lens displacement, which also involves relative lateral movement of the image sensor and lens assembly 20. Furthermore, the rotation of the image sensor may be used to stabilize the image against rotation of the camera device 1 about the optical axis O. This type of stabilization is not achieved by the type of camera device disclosed in WO-2013/175197 and WO2-014/083318 that provides OIS-lens shifting.

The SMA wire 40 is driven by a control circuit implemented in the IC chip 30. In particular, the control circuit generates a drive signal for each SMA wire 40 and provides the drive signal to the SMA wire 40.

The control circuit 30 receives an output signal of the gyro sensor 31 serving as a vibration sensor. The gyro sensor 31 detects vibrations that the camera apparatus 1 is experiencing, and its output signal is indicative of these vibrations, in particular the angular velocity of the camera lens element 20 in three dimensions. The gyroscopic sensor 31 is typically a pair of micro gyroscopes for detecting vibrations about three axes, two transverse axes of the photosensitive area 7 and also the optical axis O. More generally, a greater number of gyroscopes or other types of vibration sensors may be used.

The drive signal is generated by the control circuit in response to the output signal of the gyro sensor 31 to drive the movement of the image sensor assembly 12 to stabilize the image focused on the image sensor by the camera lens element 20 to provide OIS. The drive signal may be generated using resistive feedback control techniques, for example as disclosed in any of WO-2013/175197, WO-2014/076463, WO-2012/066285, WO-2012/020212, WO-2011/104518, WO-2012/038703, WO-2010/089529 or WO-2010/029316, each of which is incorporated herein by reference.

The camera device 1 may be incorporated into a portable electronic device, such as a mobile phone or tablet computer. Accordingly, a portable electronic device comprising the camera device 1 is provided. The portable electronic device may include a processor. Super-resolution imaging may be provided in the camera device 1 and/or the portable electronic device. For example, super-resolution imaging is achieved by combining two or more images captured at positions offset from each other by a sub-pixel distance.

For this purpose, the image sensor assembly is controllably moved between two or more positions, which are offset from each other by a sub-pixel distance in a direction parallel to the photosensitive area 7. Light falling onto the center of the pixel at one location (and thus can be used to capture an image) thus falls between the pixels at another location. The control circuit may actuate the SMA wire 40 to controllably move the image sensor assembly in this manner. The sub-pixel distance is a distance smaller than the pixel pitch of the photosensitive region 7. The pixel pitch refers to the distance between the centers of two adjacent pixels.

The image sensor assembly can be controllably moved to a positioning accuracy of 0.5 μm or less. A particular advantage is achieved in the case of an actuator device comprising a plurality of SMA wires, since SMA provides a high actuation force compared to other forms of actuator. This may facilitate accurate positioning of the image sensor assembly relative to the support structure.

The two or more positions may be rest positions, so the image sensor assembly may stop at each of the two or more positions before moving to the next of the two or more positions. The two or more positions may deviate from each other in a direction along the pixel row and/or the pixel column of the photosensitive region. The two or more positions may include i) one or more positions offset from a starting position by a sub-pixel distance along the pixel row, and ii) one or more positions offset from a starting position by a sub-pixel distance along the pixel column. Alternatively, the two or more positions may include one or more positions along the pixel row and along the pixel column offset from the starting position by a sub-pixel distance.

An image is captured at each of the two or more locations using an image sensor. The controller may control the image sensor to capture an image. The controller may be implemented as part of a control circuit on the IC chip 30 or as part of another circuit on the IC chip 30. Alternatively, the controller may be implemented as part of another IC forming part of the camera device 1. Further, the controller may alternatively be implemented as part of a processor forming part of the portable electronic device.

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

It will be appreciated that many other variations of the above-described embodiments are possible. For example, the support device 110, 120, 130 may comprise any combination of the support devices 110, 120, 130 described above. The roller support 110 may comprise rolling elements on both sides of the image sensor assembly 12 in a direction perpendicular to the photosensitive area 7, such as the rolling elements shown in fig. 5 and the rolling elements shown in fig. 2 or 6. The support means 110, 120, 130 may comprise one or more rolling supports of fig. 2, 5 and 6 and one or more flexing means of fig. 7 to 10.

Any of the above-described support means 110, 120, 130 may be combined with any of the above-described arrangements of the gap 104 and/or the region of the heat transfer material 103.

Super resolution imaging may be achieved using an actuator assembly having any support means, including support means comprising a continuous sliding support that does not provide the gap 104. The high actuation force of the SMA wire 40 may allow for accurate positioning by overcoming any frictional forces caused by such a continuous sliding support.

The term SMA wire may refer to any suitably shaped element comprising SMA. The SMA wire may be elongate and may have a circular cross-section or any other shape. The cross-section may vary along the length of the SMA wire. It is also possible that the length of the SMA wire (regardless of definition) may be similar to one or more of the other dimensions of the SMA wire. The SMA wire may be flexible. Thus, when connected between two elements, the SMA wire may only be able to apply a force that urges the two elements together, which force is applied when the SMA wire is tensioned. Alternatively, the wire may be beam-like or rigid. The SMA wire may or may not include material(s) and/or component(s) other than SMA.

Claims

1. An actuator assembly, comprising:

a support structure;

an image sensor assembly comprising an image sensor having a photosensitive region, wherein the image sensor assembly is supported on the support structure such that a gap is formed between the image sensor assembly and the support structure on a side of the image sensor assembly facing away from the photosensitive region; and

a region of heat transfer material disposed in the gap, wherein the heat transfer material is arranged to transfer heat between the image sensor assembly and the support structure, and wherein the heat transfer material is configured to deform to allow the image sensor assembly to move relative to the support structure.

2. The actuator assembly of claim 1, wherein the image sensor assembly is supported on the support structure in a manner that allows the image sensor assembly to move relative to the support structure in any direction parallel to a plane in which the photosensitive region extends and/or in a manner that allows the image sensor assembly to rotate about any axis orthogonal to the plane in which the photosensitive region extends.

3. Actuator assembly according to claim 1 or 2, wherein the gap extends in a direction perpendicular to the photosensitive region for a distance in the range of between 10 and 300 μm, preferably between 20 and 200 μm, further preferably between 50 and 100 μm.

4. The actuator assembly according to any of the preceding claims, wherein the support structure and/or the image sensor assembly comprises a recess on a surface facing the gap, wherein the heat transfer material is disposed within the recess.

5. The actuator assembly according to any of the preceding claims, wherein the total contact area of the heat transfer material with the image sensor assembly is at least 0.1 times, preferably in the range of 0.2 to 4 times, further preferably in the range of 1 to 4 times the area of the photosensitive area.

6. Actuator assembly according to any of the preceding claims, wherein the heat transfer material has a thermal conductivity of more than 0.1W/K, optionally wherein the heat transfer material comprises thermally conductive particles, in particular metal particles.

7. The actuator assembly according to any of the preceding claims, wherein the heat transfer material undergoes shear deformation when the image sensor assembly is moved relative to the support structure, optionally wherein the shear modulus of the heat transfer material (in a direction parallel to the movement) is less than 100kPa, preferably less than 10kPa, further preferably less than 1kPa.

8. The actuator assembly according to any one of the preceding claims, wherein the heat transfer material comprises one or more of rubber, silicone, gel and liquid.

9. The actuator assembly of any one of the preceding claims, comprising a bearing device configured to support the image sensor assembly on the support structure to form the gap, wherein the bearing device is configured to allow the image sensor assembly to move relative to the support structure.

10. The actuator assembly of claim 9, wherein the bearing means comprises a rolling bearing comprising rolling elements disposed between the image sensor assembly and the support structure.

11. The actuator assembly of claim 10, wherein the rolling element is disposed on a side of the image sensor assembly opposite the gap.

12. The actuator assembly of claim 9, wherein the support means comprises flexing means.

13. The actuator assembly of claim 12, wherein the flexing means comprises a flexible sheet, wherein the flexible sheet extends in a direction perpendicular to the photosensitive area, the flexible sheet comprising two first arms and one or two second arms,

Wherein the two first arms are parallel and face each other and are mechanically connected to opposite ends of the image sensor assembly, and

wherein each of the one or two second arms is perpendicular to the two first arms and mechanically connected to the support structure.

14. The actuator assembly of claim 13, wherein the flexible sheet comprises at least two flexible printed circuits, wherein the flexible printed circuits are electrically connected to the image sensor assembly.

15. The actuator assembly of claim 12, wherein the flexure means comprises three or more beams extending between the image sensor assembly and the support structure in a direction perpendicular to the photosensitive region.

16. The actuator assembly of claim 15, wherein each beam comprises a first portion and a second portion that are parallel to each other and each extend in a direction perpendicular to the photosensitive region, wherein the first portion is connected to the image sensor assembly at one end and the second portion is connected to the support structure at one end, and wherein the other end of the first portion and the other end of the second portion are connected to each other.

17. The actuator assembly according to any of the preceding claims, further comprising a plurality of actuator members arranged, when selectively driven, to enable movement of the image sensor assembly relative to the support structure in any direction transverse to the photosensitive region and/or rotation of the image sensor assembly about an axis orthogonal to the photosensitive region.

18. The actuator assembly of claim 17, wherein the plurality of actuator members comprises a plurality of shape memory actuator members.

19. The actuator assembly of claim 17 or 18, further comprising a control circuit arranged to drive the actuator member, wherein the control circuit is configured to drive the actuator member so as to controllably move the photosensitive region to two or more positions, wherein two or more positions deviate from each other in a direction parallel to the photosensitive region by a distance less than a pitch between pixels of the photosensitive region.

20. The actuator assembly of claim 19, further comprising a controller configured to control the image sensor to capture images at each of the two or more locations and to combine the captured images to create a super-resolution image.

21. An actuator assembly, comprising:

a support structure;

an image sensor assembly including an image sensor having a photosensitive region;

a plurality of shape memory alloy actuator members arranged to enable movement of the image sensor assembly relative to the support structure in any direction transverse to the photosensitive region when selectively driven, and

a control circuit configured to drive the actuator member so as to controllably move the photosensitive region between two or more positions that are offset from each other in a direction parallel to the photosensitive region by a distance less than a pitch of pixels of the photosensitive region.

22. The actuator assembly of claim 21, further comprising a controller configured to control the image sensor to capture a first image in a first rest position and a second image in a second rest position, the controller configured to combine the first image and the second image to create a super-resolution image, and/or wherein the controller is configured to control the image sensor to capture a set of more than two images at different rest positions, and to combine the set of images to create a super-resolution image.

23. The actuator assembly of claim 21 or 22, further comprising a bearing device configured to support the image sensor assembly on the support structure in a manner that allows the image sensor assembly to move relative to the support structure, thereby forming a gap between the image sensor assembly and the support structure on a side of the image sensor assembly facing away from the photosensitive region.

24. The actuator assembly of claim 23, wherein the support assembly comprises a rolling support or a flexure device.

25. The actuator assembly of claim 23 or 24, further comprising a region of heat transfer material disposed in the gap, wherein the heat transfer material is arranged to transfer heat between the image sensor assembly and the support structure, and wherein the heat transfer material is configured to deform to allow the image sensor assembly to move relative to the support structure.

26. An actuator assembly, comprising:

a support structure;

a moving part supported on the support structure, wherein one of the support structure and the moving part comprises an image sensor having a photosensitive area; and

A bearing device configured to support the moving component on the support structure, wherein the bearing device is configured to allow the moving component to move relative to the support structure;

wherein at least one of the support structure and the moving part comprises at least one plate provided with a hole extending at least partially through the plate for receiving the bearing means.

27. The actuator assembly of claim 26, wherein the at least one plate comprises a conductor layer of the support structure for transmitting signals to and/or from an actuator.

28. The actuator assembly of claim 26 or 27, wherein the at least one plate comprises an end of a flexure fixed relative to the moving part.

29. The actuator assembly of any one of claims 26 to 28, wherein the at least one plate comprises a moving plate on which the image sensor is mounted.

30. The actuator assembly of claim 29, wherein the aperture extends only partially through the moving plate.

31. An actuator assembly according to any one of claims 26 to 30, wherein the bearing means comprises a rolling bearing comprising a rolling element disposed between the moving part and the support structure.

32. The actuator assembly of claim 31, wherein the rolling bearing has a diameter that is at least half of a diameter of the bore.

33. An actuator assembly according to claim 31 or 32, wherein the rolling element is provided on the same side of the moving part as the image sensor.

34. The actuator assembly of any one of claims 26 to 33, wherein the moving plate of the moving member is configured to abut a surface of the support structure when the relative displacement between the moving member and the support structure is above a threshold distance, thereby functioning as an end stop.

35. An actuator assembly, comprising:

a support structure;

an image sensor assembly comprising an image sensor having a photosensitive region, wherein the image sensor assembly is supported on the support structure;

one or more bearings configured to support the image sensor assembly on the support structure, the one or more bearings configured to allow movement of the image sensor assembly relative to the support structure; and

A supporting impact protection structure comprising a cantilever structure included in the support structure or the image sensor assembly, the one or more supports being located on a free end of the cantilever structure.

36. The actuator assembly of claim 35, wherein the cantilever structure is formed by one or more cutouts in a plate of the support structure or the image sensor assembly.

37. An actuator assembly, comprising:

a support structure;

a moving part supported on the support structure, wherein one of the support structure and the moving part comprises an image sensor having a photosensitive area;

one or more bearings configured to support the moving component on the support structure, the one or more bearings configured to allow the moving component to move relative to the support structure; and

a supporting impact protection structure comprising a cantilever structure included in the moving part, the one or more supports being located on a free end of the cantilever structure.

38. The actuator assembly of claim 37, wherein the cantilever structure is formed by one or more cutouts in a plate of the moving member.

39. An actuator assembly according to any one of claims 35 to 38, comprising:

an end stop protruding from one of the support structure and the moving member toward the other of the support structure and the moving member such that the end stop extends partially through a gap between the support structure and the moving member held by the one or more bearings.

40. An actuator assembly, comprising:

a support structure;

an image sensor assembly comprising an image sensor having a photosensitive region, wherein the image sensor assembly is supported on the support structure; and

a flexure device configured to support the image sensor assembly on the support structure in a manner that allows the image sensor assembly to move relative to the support structure in any direction parallel to a plane in which the photosensitive region extends and/or in a manner that allows the image sensor assembly to rotate about any axis orthogonal to the plane in which the photosensitive region extends.

41. The actuator assembly of claim 40, wherein said flexing means comprises a flexible sheet, wherein said flexible sheet extends in a direction perpendicular to said photosensitive area, said flexible sheet comprising two first arms and one or two second arms,

42. The actuator assembly of claim 41, wherein said flexible sheet comprises at least two flexible printed circuits, wherein said flexible printed circuits are electrically connected to said image sensor assembly.

43. The actuator assembly of claim 40, wherein said flexure means comprises three or more beams extending between said image sensor assembly and said support structure in a direction perpendicular to said photosensitive region.

44. The actuator assembly of claim 43, wherein each beam comprises a first portion and a second portion that are parallel to each other and each extend in a direction perpendicular to the photosensitive region, wherein the first portion is connected to the image sensor assembly at one end and the second portion is connected to the support structure at one end, and wherein the other end of the first portion and the other end of the second portion are connected to each other.

45. The actuator assembly of claim 43 or 44, comprising:

a plurality of SMA wires arranged to enable movement of the image sensor assembly relative to the support structure in any direction parallel to a plane in which the photosensitive region extends and/or to enable rotation of the image sensor assembly about any axis orthogonal to the plane in which the photosensitive region extends;

wherein at least one of the beams forms part of an electrical connection from the support structure to at least one of the SMA wires.

46. An actuator assembly, comprising:

a support structure;

flexing means configured to support the moving member on the support structure in a manner allowing the moving member to move relative to the support structure in any direction parallel to the plane in which the photosensitive region extends and/or in a manner allowing the moving member to rotate about any axis orthogonal to the plane in which the photosensitive region extends,

Wherein the flexure means comprises three or more beams extending between the moving part and the support structure in a direction perpendicular to the photosensitive area, wherein each beam comprises a first portion and a second portion, which are parallel to each other and each extend in a direction perpendicular to the photosensitive area, wherein the first portion is connected to the moving part at one end and the second portion is connected to the support structure at one end, and wherein the other end of the first portion and the other end of the second portion are connected to each other.

47. The actuator assembly of claim 46, wherein the first portion is connected at one end to the moving member via a movable portion that is compliant in a direction perpendicular to the photosensitive region such that any force acting on the moving member in a direction perpendicular to the photosensitive region is at least partially absorbed by bending of the movable portion, thereby protecting the flexure device.

48. The actuator assembly of claim 46 or 47, wherein the second portion is connected at one end to the support structure via a portion that is compliant in a direction perpendicular to the photosensitive region, such that any forces acting on the moving member in a direction perpendicular to the photosensitive region are at least partially absorbed by bending of the portion, thereby protecting the flexure device.

49. An actuator assembly according to claim 47 or 48, comprising one or more end stops configured to limit the extent to which the moving member can move in a direction perpendicular to the photosensitive region due to bending of the movable portion or portions.

50. The actuator assembly of any one of claims 46 to 49, wherein the moving component comprises the image sensor.

51. The actuator assembly of any one of claims 46 to 49, wherein the moving member comprises a lens and another actuator for moving the lens along an axis perpendicular to the photosensitive region.

52. The actuator assembly of claim 51, wherein at least one of the beams forms part of an electrical connection from the support structure to the other actuator.

53. The actuator assembly of any one of claims 46 to 52, comprising:

a plurality of SMA wires arranged to enable movement of the moving part relative to the support structure in any direction parallel to a plane in which the photosensitive region extends and/or to enable rotation of the moving part about any axis orthogonal to the plane in which the photosensitive region extends;

54. An actuator assembly, comprising:

a support structure defining a main plane;

a moving part configured to receive the image sensor;

a plurality of SMA wires arranged to enable movement of the moving part relative to the support structure in any direction parallel to the main plane and/or rotation of the moving part about any axis orthogonal to the main plane; and

one or more end stops configured to limit movement of the moving member relative to the support structure, wherein each end stop includes a surface area included in the support structure and a surface area included in the moving member.

55. The actuator assembly of claim 54, wherein the actuator assembly does not include the image sensor or any other component incorporated in a normal assembly order after the image sensor.

56. The actuator assembly of claim 54 or 55, wherein the one or more end stops are configured to limit movement of the moving member relative to the support structure in a direction parallel to the main plane.