Patent Publication Number: US-9899938-B2

Title: Miniature MEMS actuator assemblies

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 14/543,847, filed Nov. 17, 2014, which is hereby incorporated by reference in its entirety. 
     U.S. patent application Ser. No. 14/543,847 is a continuation of and claims the benefit of and priority to U.S. patent application Ser. No. 13/843,107, filed Mar. 15, 2013 and entitled “MINIATURE MEMS ACTUATOR ASSEMBLIES” which is hereby incorporated by reference in its entirety. 
     U.S. patent application Ser. No. 13/843,107 is a continuation-in-part of and claims the benefit of and priority to U.S. patent application Ser. No. 12/946,515 filed Nov. 15, 2010 and entitled “ROTATIONAL COMB DRIVE Z-STAGE” which is hereby incorporated by reference in its entirety. 
     U.S. patent application Ser. No. 13/843,107 is a continuation-in-part of and claims the benefit of and priority to U.S. patent application Ser. No. 13/247,895 filed Sep. 28, 2011 and entitled “OPTICAL IMAGE STABILIZATION USING TANGENTIALLY ACTUATED MEMS DEVICES” which is hereby incorporated by reference in its entirety. 
     U.S. patent application Ser. No. 13/843,107 is a continuation-in-part of and claims the benefit of and priority to U.S. patent application Ser. No. 13/247,888 filed Sep. 28, 2011 and entitled “MEMS ACTUATOR DEVICE DEPLOYMENT” which is hereby incorporated by reference in its entirety. 
     U.S. patent application Ser. No. 13/247,888 is a continuation-in-part of and claims the benefit of and priority to U.S. patent application Ser. No. 12/946,670 entitled “LINEARLY DEPLOYED ACTUATORS”, Ser. No. 12/946,657 entitled “CAPILLARY ACTUATOR DEPLOYMENT”, and Ser. No. 12/946,646 entitled “ROTATIONALLY DEPLOYED ACTUATORS”, all filed Nov. 15, 2010, the entire disclosure of each of which are hereby incorporated by reference in their entirety. 
     U.S. patent application Ser. No. 13/843,107 is a continuation-in-part of and claims the benefit of and priority to U.S. patent application Ser. No. 13/247,898 filed Sep. 28, 2011 and entitled “MULTIPLE DEGREE OF FREEDOM ACTUATOR” which is hereby incorporated by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     One or more embodiments of the invention generally relates to actuators for optical elements, such as mirrors or lenses, and more particularly for example, to embodiments of actuator assemblies useful in, for example, miniature cameras and the like, that provide movement in multiple degrees of freedom. 
     RELATED ART 
     Actuators for use in miniature cameras and other devices are well known. Such devices typically comprise voice coils that are used to move a lens for focusing, zooming, or optical image stabilization. 
     Microelectromechanical systems (MEMS) actuators are also known. Examples of MEMS actuators include comb drives, scratch drives, and thermal drives. Microminiature MEMS actuators can be made using well known integrated circuit (IC) fabrication techniques. MEMS actuators can be used in a variety of applications. For example, MEMS actuators can be used to move a lens to so as to facilitate autofocus, zoom and image stabilization functions in miniature cameras. Accordingly, it is desirable to provide improved MEMS actuator devices for such applications. 
     Miniature cameras can be used in a variety of different electronic devices. For example, miniature cameras are commonly used in cellular telephones, laptop computers, and surveillance devices and in many other applications. As the size of electronic devices continues to shrink, the size of miniature cameras that are part of such devices typically must be reduced as well. In light of this, it becomes desirable to provide ways and means for reducing the size of miniature cameras, while at the same time retaining the advanced functionalities of larger, more expensive standalone cameras. 
     Accordingly, a need exists for actuator assemblies useful in, for example, miniature cameras and the like that are small, easier and less costly to manufacture, and which are capable of providing movement of optical elements in multiple degrees of freedom to effect a variety of functions. 
     SUMMARY 
     In accordance with one or more embodiments of the present disclosure, various embodiments of miniature actuator assemblies are provided, together with methods for making and using them, that are useful in, for example, miniature cameras and the like, that are small, easier and less costly to manufacture, and that are capable of providing movement of optical elements in multiple degrees of freedom to effect a variety of functions. 
     In one example embodiment, an electrostatic actuator includes a generally planar fixed frame, a generally planar moving frame coupled to the fixed frame by a flexure for substantially coplanar, perpendicular movement relative to the fixed frame, a plurality of interdigitated teeth, a fixed portion of which is attached to the fixed frame and a moving portion of which is attached to the moving frame, and an elongated output shaft having opposite input and output ends, the input end being coupled to the moving frame. 
     In another embodiment, an electrostatic actuator device includes an L-shaped support frame having an upright leg and a lateral leg extending perpendicularly therefrom, an output coupler, and a pair of the above actuators. The output ends of the output shafts of the actuators are coupled to the output coupler, the fixed frame of a first one of the actuators is attached to the upright leg such that the output shaft of the first actuator moves the output coupler rectilinearly and in a first direction, and the fixed frame of a second one of the actuators is attached to the lateral leg such that the output shaft of the second actuator moves the output coupler rectilinearly and in a second direction perpendicular to the first direction. 
     The actuators and actuator devices can be used for making a variety of miniature lens barrels and miniature camera modules of the type used in electronic host devices, such as mobile phones, computers and the like. 
     The scope of this invention is defined by the claims appended hereafter, which are incorporated into this section by reference. A more complete understanding of the features and advantages of the novel miniature actuator assemblies of the disclosure and the methods for making and using them will be afforded to those skilled in the art by a consideration of the detailed description of some example embodiments thereof presented below, particularly if such consideration is made in conjunction with the appended drawings, briefly described below, wherein like reference numerals are used to identify like elements illustrated in one or more of the figures thereof. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1A  is a schematic representation of an actuator assembly incorporating three actuators, each capable of two degrees of freedom (two-DOF) of orthogonal movement in accordance with an embodiment of the disclosure. 
         FIG. 1B  is a schematic representation of an actuator assembly incorporating three actuators, each capable of one-DOF of movement in accordance with an embodiment of the disclosure. 
         FIG. 1C  is a schematic representation of an actuator assembly incorporating three actuators, one capable of three-DOF of orthogonal movement, one capable of two degrees of freedom of orthogonal movement, and one capable of one-DOF of movement in accordance with an embodiment of the disclosure. 
         FIG. 2A  is a top plan view of an example embodiment of a two-DOF actuator device in accordance with an embodiment of the disclosure, shown in an as-fabricated state and prior to its deployment for operational use. 
         FIG. 2B  is a top plan view of the example two-DOF actuator device of  FIG. 2A , shown after being deployed for operational use in accordance with an embodiment of the disclosure. 
         FIG. 3A  is an enlarged partial detail plan view of fixed and moving frames and associated portions of interdigitated teeth of one of the actuators of the example actuator device of  FIG. 2A , showing the relative position of the frames and teeth prior to deployment in accordance with an embodiment of the disclosure. 
         FIG. 3B  is an enlarged partial detail plan view of the fixed and moving frames and associated portions of interdigitated teeth of one of the actuators of the example actuator device of  FIG. 2B , showing the relative position of the frames and teeth after deployment in accordance with an embodiment of the disclosure. 
         FIGS. 4A and 4B  are upper, left side and upper, right side perspective views, respectively, of an example embodiment of a “monopod,” or “cross-axis” flexure in accordance with an embodiment of the disclosure. 
         FIGS. 5A-5H  are top-and-side perspective views of the sequential steps of an example embodiment of a method for assembling a miniature lens barrel assembly utilizing a plurality of the 2DOF actuator devices of  FIG. 2B  in accordance with an embodiment of the disclosure. 
         FIG. 6  is a top-and-side perspective view of six example embodiments of one-DOF actuator devices in accordance with an embodiment of the disclosure, shown disposed in a hexagonal arrangement. 
         FIG. 7  is a side elevation of the hexagonal arrangement of the example one-DOF actuator devices of  FIG. 6  in accordance with an embodiment of the disclosure. 
         FIG. 8  is a top-and-side perspective view of the hexagonal arrangement of the example one-DOF actuator devices of  FIG. 6 , showing the devices respectively disposed over a corresponding side surface of a hexagonal barrel to form an example lens barrel assembly in accordance with an embodiment of the disclosure. 
         FIG. 9  is a top-and-side perspective view of the lens barrel assembly, showing an example embodiment of a support platform for an optical element coupled to a corresponding output connector of each of the actuator devices in accordance with an embodiment of the disclosure. 
         FIG. 10  is a top-and-side perspective view of the lens barrel and support platform assembly of  FIG. 9 , shown disposed within a concentric protective housing in accordance with an embodiment of the disclosure. 
         FIG. 11  is a top-and-side perspective view of three example one-DOF actuator devices, shown disposed in a triangular arrangement in accordance with an embodiment of the disclosure. 
         FIG. 12  is a top-and-side perspective view of the triangular arrangement of the example one-DOF actuator devices, showing the devices respectively disposed over alternating ones of corresponding side surfaces of a hexagonal barrel to form another example embodiment of a lens barrel assembly in accordance with an embodiment of the disclosure. 
         FIG. 13  is a top-and-side perspective view of the lens barrel assembly of  FIG. 12 , showing another example embodiment of an optical element support platform coupled to corresponding ones of the output connectors of the actuator devices in accordance with an embodiment of the disclosure. 
         FIGS. 14A-14E  are top plan views of the sequential steps of an example embodiment of a method for assembling an example embodiment of a miniature camera module utilizing a plurality of the two-DOF actuator devices of  FIG. 2B  in accordance with an embodiment of the disclosure, and  FIG. 14F  is a top-and-side perspective view of the example camera module. 
         FIGS. 15A and 15B  are top plan and elevational cross-sectional views, respectively, of an example embodiment of a frustoconical lens barrel of a type useful in the example miniature camera module of  FIGS. 14A-14F  in accordance with an embodiment of the disclosure. 
         FIGS. 16A and 16B  are top-and-side perspective and elevational cross-sectional views, respectively, of the miniature camera module of  FIGS. 14A-14F , shown surrounded by a concentric protective housing in accordance with an embodiment of the disclosure. 
         FIG. 17  is a schematic cross-sectional side elevation view of another example embodiment of a miniature camera module in accordance with an embodiment of the disclosure, showing a pair of actuator assemblies for moving corresponding ones of a pair of lenses independently of each other and relative to a plurality of fixed lenses and an image sensor disposed within the example camera module. 
     
    
    
     DETAILED DESCRIPTION 
     In accordance with embodiments of the present invention, miniature actuator assemblies are provided, together with methods for making and using them, that are useful in, for example, miniature cameras and the like, and that are capable of providing precisely controlled movement of optical elements in multiple degrees of freedom (DOFs) to effect a variety of functions, such as focusing, zooming and image stabilization (IS) functions. 
     As used herein, a “one-, two-, or three-DOF actuator” is an actuator that is capable of exerting a force on an object in one, two or three directions, respectively, which directions are, except for the first actuator, mutually orthogonal. Actuator devices or assemblies can be confected using such actuators that are capable of driving a “payload,” such as a lens, in one or more directions of rectilinear and/or rotational movement relative to an X, Y, Z coordinate system, i.e., ±X, ±Y, ±Z, ±θ X , ±θ Y  and/or ±θ Z . 
     For example, an embodiment of an actuator device incorporating three one-DOF actuators that is capable of moving a payload, e.g., a mounting platform and lens in 3 DOFs of movement, viz., ±Z, ±θ X  and ±θ Y , is described in commonly owned U.S. patent application Ser. No. 12/946,515, filed Nov. 15, 2010, the entire disclosure of which is incorporated herein by reference. 
     Another embodiment of an actuator device incorporating three one-DOF actuators that is capable of moving a payload in 3 DOFs of movement, viz., ±X, ±Y and ±θ Z , is described in commonly owned U.S. patent application Ser. Nos. 13/247,895 and 13/247,888, both filed Sep. 28, 2011, both entire disclosures of which are incorporated herein by reference. 
     Yet another embodiment of an actuator device incorporating three two-DOF actuators that is capable of moving a payload in six DOFs of movement, viz., ±X, ±Y, ±Z, ±θ X , =θ Y  and ±θ Z , is described in commonly owned U.S. patent application Ser. No. 13/247,898, filed Sep. 28, 2011, the entire disclosure of which is incorporated herein by reference. 
     As discussed in the foregoing references, the multiple DOF actuator devices can be advantageously fabricated as monolithic, generally planar microelectromechanical (MEMS) structures incorporating electrostatic “comb drives” from a silicon wafer using well-known wafer-scale photolithographic techniques. 
       FIGS. 1A-1C  are schematic representations of three actuator devices or assemblies  100 A,  100 B and  100 C, each incorporating a plurality of actuators, each of which is capable of either one-, two- or three-DOFs of movement. Each of the three actuators  100 A,  100 B and  100 C is capable of moving a payload P, centered on the Z axis, in six DOFs of movement, viz., ±X, ±Y, ±Z, ±θ X , ±θ Y  and ±θ Z . 
     For example, in  FIG. 1A , the actuator assembly  100 A comprises three two-DOF actuators  102 , i.e., each capable of exerting an “in-plane” force  104 , i.e., one lying in the X-Y plane, and an “out-of-plane” force  106 , i.e., one normal to the X-Y plane. Each of the actuators  102  is coupled to the payload P by flexures, represented by the dashed lines  108 , such that the respective in-plane forces  104  exerted by the actuators  102  act tangentially on the payload P. Thus, simultaneous in-plane actuation of the actuators  102  causes rotation of the payload P about the Z axis, i.e., ±θ Z  displacement, and independent in-plane actuation of the actuators  102  can cause translation of the payload P along an axis in the X-Y plane, i.e., ±X and/or ±Y displacements. Similarly, simultaneous actuation of the actuators  102  in the out-of-plane direction causes translation of the payload P along the Z axis, i.e., ±Z displacement, and independent out-of-plane actuation of the actuators  102  causes rotation of the payload P about an axis lying in the X-Y plane, i.e., ±θ X  and/or ±θ Y  displacements. 
     In  FIG. 1B , the actuator assembly  100 B comprises six one-DOF actuators  110 , three of which are capable of exerting an in-plane force  104 , and three of which are capable of exerting an out-of-plane force  106 , i.e., normal to the X-Y plane. As those of some skill will appreciate, suitable in-plane and/or out-plane actuation of each of the six one-DOF actuators  110  will result in movement of the payload P in six DOFs, viz., ±X, ±Y, ±Z, ±θ X , ±θ Y  and ±θ Z . 
     In  FIG. 1C , the actuator assembly  100 C incorporates three actuators, viz., one 3-DOF actuator  114 , i.e., one capable of exerting 2 orthogonal in-plane forces  104  and one out-of plane force  106 , as well as one 2-DOF actuator  102  and one one-DOF actuator  110  of the types described above. And as above, suitable simultaneous and/or independent actuation of the three actuators  102 ,  110  and  114  will result in movement of the payload P in six DOFs, viz., ±X, ±Y, ±Z, ±θX, ±θY and ±θZ. 
     In the context of miniature cameras, for example, cellphone cameras, it is desirable to provide miniature, six DOF (or less) actuator assemblies for moving, e.g., a single lens, to effect, for example, autofocus, zooming and/or image stabilization functions. As discussed above in connection with  FIG. 1A , one advantageous embodiment of a 6 DOF actuator assembly can include three two-DOF actuators, wherein each actuator has one out-of-plane or vertical (e.g., parallel to an optical axis of the lens) DOF and one in-plane, tangentially acting DOF. 
     However, as discussed above in U.S. patent application Ser. No. 13/247,898, fabrication of a 2 DOF actuator using MEMS techniques results, at least initially, in a generally planar actuator with two orthogonal in-plane actuation sections, and additional fabrication steps must be taken to convert one of these sections to out-of-plane operation. It therefore becomes desirable to provide alternative embodiments of actuator assembly methods that utilize exclusively planar arrangements. However, as discussed in more detail below, through the use of a flexible actuator assembly substrate, assembly and wiring of an actuator assembly can take place in a substantially planar fashion, and then the substrate can be folded into the final three-dimensional configuration necessary for the desired orthogonal in-plane and out-of-plane operation. 
       FIG. 2A  is a top plan view of an example embodiment of a two-DOF MEMS actuator device  200  in accordance with the present invention, shown in an as-fabricated state and prior to its “deployment” for operational use, and  FIG. 2B  is a top plan view of the example actuator device  200 , shown after being deployed for use. As can be seen in  FIGS. 2A and 2B , the actuator device  200  comprises two substantially similar one-DOF electrostatic comb drive actuators  202  and  204  coupled together in a mutually orthogonal arrangement by a fixed, L-shaped support frame comprising an upright leg  206  and a lateral leg  208  extending perpendicularly therefrom. 
     As illustrated in  FIGS. 2A and 2B , in each actuator  202  and  204 , respective pluralities of fixed frames  210  extend perpendicular to the fixed upright and lateral legs  206  and  208 , and a moving or output leg  212  is coupled to a corresponding one of each of the upright and lateral legs  206  and  208  by a pair of elongated flexures  214  that are configured to enable each moving leg  212  to move substantially parallel to its corresponding upright or lateral leg  206  or  208 . Respective pluralities of moving frames  216  extend perpendicular to each of the two moving legs  212 . Each of the moving or output legs  212  of the two actuators  202  and  204  is coupled to a single output coupler  218  through an elongated output shaft  220 . As discussed in more detail below, an output end of each output shaft  220  is coupled to the output coupler  218  by a first “cross-axis” or “monopod” flexure  222 , and an input end of each output shaft  220  is coupled to an associated one of the output legs  212  through a second monopod flexure  222 . 
     As further illustrated in  FIGS. 2A and 2B , each of the fixed and moving frames  210  and  216  includes an associated plurality of electrostatic comb drive teeth  224  extending perpendicularly therefrom which are interdigitated with each other to define an electrostatic comb drive “bank.” When a differential voltage is selectively applied to the fixed and moving frames  210  and  216  of the comb drive banks of a given actuator  202  or  204 , the moving frames  210 , and hence, the associated output leg  212  and output shaft  220  of the given actuator, are urged orthogonally toward or away from the associated fixed frames  210  of the actuator. Thus, actuation of the vertical one-DOF actuator  202  will result in a movement of the associated output shaft  220 , and hence, the output coupler  218 , in the plane of the actuator device  200  and vertically in the direction of the double-headed arrow  226  in  FIG. 2B . Similarly, actuation of the lateral one-DOF actuator  204  will result in movement of the output coupler  218  in the plane of the actuator device  200  and laterally in the direction of the double-headed arrow  228  of  FIG. 2B . As will be evident to those of some skill, the one-DOF actuators  202  and  204  can be simultaneously actuated with selective differential voltages so as to cause the output coupler  218 , and hence, a “payload” coupled to it, to move in any direction lying in the plane of the actuator device  200 . 
     In the particular example embodiment illustrated in  FIGS. 2A and 2B , each of the actuators  202  and  204  includes three electrostatic comb banks. However, it should be understood that the number of comb banks, as well as the number, length, width and pitch of the teeth  224  of the comb banks, can be widely varied, depending on the particular application at hand. 
     It should be further understood that, as discussed above, the interdigitated teeth  214  of the two one-DOF actuators of  FIG. 2B  are shown in a “deployed” position, i.e., spread apart from one another, for substantially rectilinear movement relative to each other. However, as illustrated in the enlarged detail view of the teeth  214  in  FIG. 3A , it may be seen that the interdigitated teeth  214  of the actuators  202  and  204  are initially disposed after manufacture such that the associated fixed and moving frames  210  and  216  are spaced apart by about the length of the teeth  214  for manufacturing efficiencies. Accordingly, the application of a voltage differential to the teeth  214  in this configuration cannot result in any substantial in-plane rectilinear movement of the moving frames  216  toward the fixed frames  210 , and hence, any corresponding movement of the output coupler  218  in the plane of the actuator device  200 . Therefore, to effect the latter type of movement, each of the two actuators  202  and  204  must first be deployed into a configuration that enables this type of actuation. 
     In the particular example embodiment of  FIGS. 2A and 2B , this deployment can include the provision of an over-center latch  230  on each of the upright and lateral legs  206  and  208 . The latches  230  are respectively coupled to the upright and lateral legs  206  and  208  with, e.g., a spring flexure. Each of a pair of deployment levers  232  is respectively coupled to the associated moving frames  216  with a recurvate deployment flexure  234 . Each of the deployment levers  232  has a surface disposed at an upper end of the lever that is configured as an inclined plane for a camming actuation of and a latching engagement with a corresponding one of the latches  230 . A pull ring  236  can be attached to each of the deployment flexures  234  by a spring flexure adjacent to the upper end of the deployment levers  232 . 
     During deployment, a force is applied to the pull ring  236  of each actuator  202  and  204  in the direction of the arrows  238  in  FIG. 2A . This causes the deployment levers  232  to rotate relative to their associated upright or lateral legs  206  or  208 . The rotation of the deployment levers  232  causes the deployment flexures  234  to urge the respective moving frames  216  rectilinearly and perpendicularly away from their associated fixed frames  210 , and to the deployed position, where the camming surface at the upper end of the each deployment lever  232  first actuates, and is then engaged by, a corresponding one of the latches  230  so as to fix the moving frames  216  in the deployed position, as illustrated in  FIG. 2B . This, in turn, results in a deployment of the teeth  214  of the moving frames  216  to the position, indicated by the phantom line  240  in the enlarged detail view of  FIG. 3B , for movement relative to the teeth  214  of the fixed frames  210  in the direction indicated by the double-headed arrows  242  in  FIG. 3B . The deployment levers  232  can then be, for example, adhesively bonded to their associated latches  230  to prevent the moving frames  216  and associated teeth  214  from returning to their previous, “un-deployed” positions as a result of, e.g., vibration or shock acting on the actuator device  200 . In this regard, it should be understood that, in some embodiments, after the actuators  202  and  204  have been deployed, the “deployment” components, i.e., the latches  230 , deployment levers  232 , deployment flexures  234  and pull rings  236  become redundant and serve no further purpose in the operation of the actuators  202  and  204 . In other embodiments, such “deployment” components may be adapted to provide various biasing and/or other actuator forces, such as spring forces related to flexing of deployment flexures  234 , for example, and/or other structurally-based influences (e.g., motion limits, shock mitigation, general alignment) on operation of actuators  202  and/or  204 , throughout the operational life of actuators  202  and/or  204 . 
     As those of some skill will understand, the elongated output shafts  220  of the actuators  202  and  204  are susceptible to “cross-talk” or “cross-coupling,” i.e., non-axial forces exerted on one of the shafts  220  by the other shaft  220 , or a force acting in a non-axial direction exerted by the associated moving leg  212  during actuation. Since both output shafts  220  are coupled to the single output coupler  218 , this can lead to some imprecision in the positioning of the latter, and hence, in the positioning of any payload coupled to it for movement. However, it has been discovered that the cross-talk, parasitic stiffness, and/or cross-coupling problems can be substantially eliminated by the provision of the “monopod” flexures  222  described above. 
       FIGS. 4A and 4B  are upper, left side and upper, right side perspective views, respectively, of the monopod flexure  222  in accordance with one example embodiment of the present invention. As can be seen in the figures, the monopod flexure  222  can comprise two “solid hinges” coupled to each other end-to-end, i.e., a corrugated “in-plane” hinge  244  that is relatively stiff in an out-of-plane direction, i.e., one normal to the plane of the actuator device  200 , and relatively flexible in an in-plane direction, and a U-shaped out-of-plane hinge  246  that is relatively flexible in the out-of-plane direction and relatively stiff in the in-plane direction. As discussed above in connection with  FIGS. 2A and 2B , the output end of each output shaft  220  is coupled to the output coupler  218  by a monopod flexure  222 , and the input end of each output shaft  220  is coupled to its associated actuator output leg  212  by another monopod flexure  222 . As a result, the output shafts  220  of each of the two actuators  204  are stiff in their respective axial directions and soft or flexible in all other directions. This effectively ensures that each actuator  202  or  204  is capable of exerting forces on the output connector  218  only in an axial direction, and that all cross-talk or cross-coupling between the two actuators  202  and  204  is eliminated. In alternative embodiments, hinge  244  may be implemented as a substantially straight and/or flat (e.g., as opposed to corrugated) in-plane hinge. In additional embodiments, hinge  246  may be coupled to an end of hinge  244  near a center-line of hinge  244  rather than at an off-center edge of an end of hinge  244 . In a similar embodiment, hinge  246  may be coupled to an end of shaft  222  near a center-line of shaft  222  rather than at an off-center edge of an end of shaft  222 . 
     It should be noted that actuator device  200  exhibits a number of benefits over other two-DOF actuator implementations. For example, embodiments of actuator device  200  may be fabricated in a smaller area than, for example, a similarly responsive two-DOF actuator device comprising a pair of nested actuators. In general, nested two-DOF actuator devices include a one-DOF actuator situated within another one-DOF actuator. As such, the outer one-DOF actuator must include sufficient structure to support and/or snub the inner one-DOF actuator, and the additional supporting/snubbing structure takes up area that could otherwise be used for comb drive structures, for example. Further, the outer one-DOF actuator must additionally manipulate the full inertia of the inner one-DOF actuator whenever it is energized, and this reduces its available power and general responsiveness, in addition to necessitating an increase in the size of its associated snubbers, which results in an additional loss of area. 
     Embodiments of the present disclosure (e.g., actuator device  200 ) may be implemented to alleviate such detriments by interconnecting substantially planar and non-nested one-DOF actuators in a manner that eliminates cross-talk and/or parasitic stiffness (e.g., characteristics analogous to inertial disadvantages in nested designs). Moreover, embodiments of actuator device  200  may be implemented with substantially smaller and/or less complex snubber structures due to, at least in part, their relatively small size and simple motion and/or operation. Because complex snubber structures are often less reliable than simpler snubber structures, in addition to being more costly to fabricate, devices including one or more embodiments of actuator device  200  are typically more reliable and/or cost effective than devices including conventional multiple-DOF actuator devices. 
     As discussed above, the assembly and electrical wiring of a multiple DOF actuator assembly can take place in a substantially planar fashion by attaching one or more generally planar multiple DOF actuator devices, such as the two-DOF actuator device  200  described above, to a flexible substrate, and the substrate can then be folded into the final three-dimensional configuration necessary to effect the desired orthogonal in-plane and out-of-plane actuations of a payload.  FIGS. 5A-5H  are top-and-side perspective views of the sequential steps involved in an example embodiment of a method for assembling a miniature lens barrel assembly  500  incorporating a six-DOF actuator assembly  502  utilizing a substrate  504  and a plurality, viz., three, of the two-DOF actuator devices  200  discussed above in connection  FIG. 2B . 
     As illustrated in  FIG. 5A , the substrate  504  can comprise, for example, a flexible printed circuit board (PCB) containing conductive traces and bonding pads and comprising, e.g., a suitable dielectric, such as Mylar, Kapton, a fiber reinforced resin, or the like. In the particular example embodiment illustrated in the figures, the substrate  504  is generally Y-shaped, with three arms  506  extending radially outward from a central portion  508 . The central portion  508  can include, e.g., a circular central aperture  510  through which light from an image can pass. Of importance, the substrate  504  should be flexible enough to allow the arms to fold downward relative to the central portion  508  about respective fold lines  512  without damaging the substrate  504 . This flexibility can be enhanced by, e.g., notching, scribing or indenting the substrate  504  along the fold lines  512  during manufacture or assembly. 
     As those of some skill will understand, it is desirable to mount the actuator devices  200  slightly above the substrate  504  such that movement of the respective moving frames  216 , output legs  212  and drive shafts  200  of the actuator devices  200  are not impeded by friction between the lower surfaces of the foregoing structures and the upper surface of the substrate  504 . To this end, a plurality, i.e., at least three, electrically conductive standoffs or solder bumps  514  can be disposed on the upper surfaces of each of the arms  506  of the substrate  504 . 
     If corresponding conductive mounting and connection pads (not illustrated) are provided on the bottom surfaces of the fixed components of the actuator devices  200 , e.g., on the L-shaped frames thereof, then, as illustrated in  FIG. 5B , respective sets of these conductive mounting and connection pads can be soldered to the standoffs or solder bumps  514  on corresponding ones of the substrate arms  508  in, e.g., a known type of solder reflow operation, and thereby effect several desirable results. For example, the actuator devices  200  will be mounted on the substrate  504  with a slight clearance below the actuator devices to enable free movement of respective moving parts, as above, an electrical connection of the actuator devices  200  to the substrate for the routing of power and control signals can be effected, and the reflow operation can be used to precisely position the actuator devices  200  relative to the substrate  504  and each other. As illustrated in  FIG. 5B , after the solder reflow operation, the substrate  504  and actuator devices  200  define a generally planar six-DOF actuator assembly  502  that can be functionally tested in the planar state, e.g., for appropriate motion of the respective output couplers  218  in the orthogonal in-plane directions  226  and  228 . 
     As illustrated in  FIG. 5C , in the next step of the method, a generally cylindrical lens barrel  516  is provided for assembly with the actuator assembly  502 . The lens barrel  516  can comprise, for example, an injection molded plastic structure having a central lumen  518  corresponding to the central aperture  510  in the central portion  508  of the substrate  504 , and flats on its side surface corresponding in location and size to corresponding ones of the arms  506  of the substrate  504 . As illustrated in  FIG. 5C , the generally planar actuator assembly  502  can be disposed over an upper end of the lens barrel  516  such that the central portion  508  of the substrate  504  is disposed on an upper end of the lens barrel  516  and the central aperture  510  of the substrate  504  is disposed concentric to the central lumen  518  of the lens barrel  516 . The central portion  508  of the substrate  504  can then be attached, e.g., by adhesive bonding, to the upper end of the lens barrel  516  such that each of the arms  508  of the substrate  504 , each bearing a corresponding one of the actuator devices  200 , overhangs an upper edge of a corresponding one of the flats on the sides of the lens barrel  516  at a corresponding one of the fold lines  512  of the substrate  504  discussed above in connection with  FIG. 5A . The interim assembly resulting from this step is illustrated in  FIG. 5C . 
     As illustrated in  FIGS. 5D-5F , the assembly method proceeds with folding the arms  506  of the substrate  502 , each bearing a corresponding one of the actuator devices  200 , downward in the direction of the arrows  520  in  FIG. 5D , until each of the arms  506  is disposed against a corresponding one of the flats on the side of the lens barrel  516 , to which a lower surfaces of the arm  506  can then be bonded using, e.g., a suitable adhesive. The resulting interim lens barrel assembly is illustrated in  FIG. 5F  and in the enlarged perspective view of  FIG. 5G . 
     In various embodiments, arms  506  may be folded downward by a mechanical press, for example, or through the action of placing a cover over lens barrel  516  (e.g., similar to annular housing  1002  described herein). In other embodiments, arms  506  may be folded downwards by capillary action developed by an adhesive applied to lens barrel  516 , such as a liquid or semi-liquid epoxy, for example. In further embodiments, arms  506  may be folded downwards by a combination of one or more of mechanical pressing, cover placement, capillary action, and/or gravity. In still further embodiments, an interim lens barrel assembly, similar to that shown in  FIG. 5F , for example, may forego substrate  504  and the various methods of folding arms  506  and, instead, mount actuator devices  200  onto appropriate surfaces of lens barrel  516  using a pick and place machine, for example. In some embodiments, substrate  504  and/or arms  506  may be adhered to lens barrel  516  (e.g., utilizing any of the folding methods described herein) prior to being coupled to actuator devices  200 , for example, and one or more actuator devices  200  may subsequently be mounted onto arms  506  by a pick and place machine (e.g., by rotating lens barrel  516  and/or arms  506  in the pick and place machine). 
     As can be seen in  FIG. 5G , the upper surfaces of the output couplings  218  of the actuator devices  200  define a plane that is disposed slightly above and parallel to an upper surface of the of the central portion  508  of the substrate  502 , i.e., slightly above the upper surface of the interim lens barrel assembly. Additionally, each of the output couplings  218  is disposed to move in the same two orthogonal directions  226  and  228  discussed above in connection with  FIG. 2B . However, as a result of the “folding” steps discussed above in connection with  FIGS. 5D-5F , while the direction of movement  228  of each actuator output coupling  218  remains in the plane defined by the upper surfaces of the output couplings  218 , the direction of movement  226  of each output coupling  218  is now disposed orthogonal to that plane, i.e., for out-of-plane movement. 
     As illustrated in  FIG. 5H , a lens support platform  522  can be attached to the upper surfaces of the output couplers  218  of the actuator devices  200  to complete the lens barrel assembly  500 . The platform  522  can be generally planar, include tangentially extending arms  524  corresponding in number and relative position of the output couplers  218  of the actuator devices  200 , and a central aperture  526  generally corresponding to the central lumen  518  of the lens barrel  516 . The platform  522  can be attached, for example, by bonding a lower surface of each of the tangential arms  524  to the upper surface of a corresponding one of actuator output couplers  218 . As discussed above in connection with  FIG. 1A , the tangential arms  524  of the platform  522  are preferably arranged such that in-plane forces exerted on the platform  522  by the two-DOF actuator devices  200 , i.e., in the direction of movement  228 , act on the platform  522  tangentially, and out-of-plane forces exerted on the platform  522  by the two-DOF actuator devices  200 , i.e., in the direction of movement  226 , act perpendicularly thereon. As discussed above, this arrangement results in a lens barrel assembly  500  that is capable of moving the platform  522 , and hence, a lens mounted thereon, in six DOFs of movement, viz., ±X, ±Y, ±Z, ±θ X , ±θ Y  and ±θ Z . 
     It may be noted that, in the particular example embodiment of  FIGS. 5A-5F , the two-DOF actuator devices  200  are three in number and are arranged in 120 degree equal angular increments around the circumfery of the substrate  504 , i.e., as in the arrangement discussed above in connection with  FIG. 1A . However, as discussed in more detail below, the techniques and methods described herein can be used to make a wide variety of useful embodiments of single and multiple DOF actuator assemblies incorporating any practical number of actuator devices and disposed in any practical arrangement desired. 
     For example, it may be noted in  FIGS. 2A and 2B  above that if the two-DOF actuator device  200  is split apart along the phantom line  250  extending through the upright leg  206  of the L-shaped support frame, a pair of substantially identical one-DOF actuator devices  202  and  204  are produced that can be used make a wide variety of single- and multiple-DOF actuator assemblies, although as a practical matter, it may be preferable to produce standalone one-DOF actuators  202  or  204  having the same features as those discussed above using the same wafer scale MEMS fabrication techniques used to produce the two-DOF devices  200 . In either case, however, as discussed below, the one-DOF actuators  202  or  204  can also be used advantageously to produce a variety of useful actuator assemblies, including six-DOF actuator assemblies. 
     Thus, as discussed above in connection with  FIG. 1B , a six-DOF actuator assembly  100 B can be fabricated using six one-DOF actuators  110  arrayed in around an axis, e.g., a Z axis, in an “alternating” hexagonal pattern, i.e., one in which the one-DOF actuators  110  alternately exert in-plane and out-of-plane forces on the payload P. 
       FIG. 6  is a top-and-side perspective view of six example embodiments of one DOF actuator devices  203  in accordance with the present invention, shown disposed in such an alternating hexagonal arrangement  600 , and  FIG. 7  is a side elevation of the hexagonal arrangement  600 . As can be seen in  FIGS. 6 and 7 , the one-DOF actuators  203  are substantially identical to each other, except that the actuators and their respective output shafts  220  and output couplers  218  are arranged to exert forces alternately in in-plane and an out-of-plane directions, respectively. As in the embodiment of  FIGS. 5A-5H  discussed above, the upper surfaces of the output couplers  218  of the out-of-plane actuators  303  define a plane  702  within which the output couplers  218  of the in-plane actuators  203  move rectilinearly. Additionally, it can be noted in  FIGS. 6 and 7  that the output couplers  218  of adjacent ones of the actuators  203  are disposed immediately adjacent to each other. 
     As illustrated in  FIG. 8 , the hexagonal pattern  600  of the one-DOF actuators  203  can be superimposed onto the generally planar side surfaces of a hexagonal lens barrel  802  in a manner similar to that discussed above in connection with  FIGS. 5A-5H , in which each of the actuators  203  occupies a corresponding flat on the lens barrel  802 . The lens barrel  802  can be fabricated from, e.g., an injection molded plastic to include a central lumen  804  within which, for example, one or more fixed lenses (not illustrated) can be disposed. The hexagonal pattern  600  can, for example, be superimposed onto the lens barrel  802  using the fold-down substrate technique discussed above in connection with  FIGS. 5A-5H . Alternatively, the actuators  203  can be attached directly to the flats of the lens barrel  802 , e.g., using three-sided recesses  806  surrounding the flats in the lens barrel  802  to precisely align the actuators  203 , but with due regard being had for the requirements of providing a slight clearance between the actuators  203  and their respective mounting surfaces and conveying electrical power and control signals to the actuators  203 , as discussed above. 
     As illustrated in  FIG. 9 , a lens support platform  902  can be attached to the upper surfaces of the respective output couplers  218  of the out-of-plane actuators  203  in a manner similar to that discussed above in connection with the embodiment of  FIG. 5H . As in that embodiment, the support platform  902  can be generally planar, include tangentially extending arms  904  corresponding in number and relative position of the output couplers  218  of the out-of-plane actuator devices  203 , and a central aperture  906  generally corresponding to the central lumen  804  of the lens barrel  802 . And, as above, the tangential arms  904  of the platform  902  are preferably arranged such that in-plane forces exerted on the platform  902  by the output couplers  218  of the in-plane actuators  203  act tangentially on the platform  902 , and out-of-plane forces exerted on the platform  902  by the output couplers  218  of the out-of plane actuators  203  act perpendicularly thereon. As discussed above, this arrangement results in a lens barrel assembly  900  that is capable of moving the platform  902 , and hence, a lens mounted thereon, in six DOFs of movement, viz., ±X, ±Y, ±Z, ±θ X , ±θ Y  and ±θ Z . 
     As illustrated in  FIG. 10 , in some embodiments, an annular housing  1002  can be disposed concentrically around the lens barrel assembly  900  to protect the actuators  203  and lens mounting platform  902  from, e.g., dirt and moisture. The protective housing can also be fabricated from an injection molded plastic, and can be configured to mount on the lens barrel assembly  900  in a snap-on fashion. Further, as discussed in more detail below, in some embodiments, an imaging device (not illustrated), such as a digital camera image sensor (i.e., a “camera on a chip”) can be disposed at the base of the lens barrel assembly  900  to convert it to a miniature camera module  1000 . 
       FIG. 11  is a top-and-side perspective view of three of the example one-DOF actuators  203  disposed in an arrangement  1100  corresponding to the sides of an equilateral triangle. It may be noted that in the actuator arrangement  1100 , the output shafts  220  of the actuators  203  are all directed vertically, i.e., out-of-plane, and that the respective upper surfaces of the output couplers  218  all face up. 
     As illustrated in  FIG. 12 , the triangular arrangement  1100  of the actuators  203  can be superimposed on the generally planar side surfaces  1204  of a lens barrel  1202  having a central lumen  1206  in a manner similar to that discussed above in connection with  FIG. 8 , i.e., using either the fold-down substrate technique described above in connection with  FIGS. 5A-5H  or by using a direct attachment technique. 
     As illustrated in  FIG. 13 , in a manner similar to that discussed above in connection with  FIG. 9 , a lens support platform  1302  can be attached to the upper surfaces of the respective output couplers  218  of the out-of-plane actuators  203  in a manner similar to that discussed above in connection with the embodiments of  FIGS. 5H and 9 . As in those embodiments, the support platform  1302  can be generally planar, include radial arms  1304  corresponding in number and relative position of the output couplers  218  of the out-of-plane actuator devices  203 , and a central aperture  1306  generally corresponding to the central lumen  1206  of the lens barrel  1202 . The radial arms  1304  of the platform  1302  are respectively coupled to the upper surfaces of the output couplers  218  such that the out-of-plane forces exerted on the platform  1302  by the output couplers  218  of the out-of plane actuators  203  act normal thereon. As those of some skill will understand, this arrangement results in a lens barrel assembly  1300  that is capable of moving the platform  1302 , and hence, a lens mounted thereon, in three DOFs of movement, viz., ±Z, θ X  and θ Y . 
       FIGS. 14A-14E  are top plan views of the sequential steps of an example embodiment of a method for assembling an example embodiment of a miniature camera module  1400  incorporating a six-DOF actuator assembly  1402  utilizing a plurality of the two-DOF actuator devices  200  of  FIG. 2B  in accordance with the present invention, and  FIG. 14F  is a top-and-side perspective view of the example camera module  1400 . 
     As discussed above in connection with  FIGS. 5A-5H , the example method of  FIGS. 14A-14F  can make use of the fold-down substrate technique, including mechanical pressing, cover placement, adhesive capillary action, gravity, and other techniques described herein. Thus, as illustrated in  FIG. 14A , the substrate  1404  can comprise, for example, a single-layer flexible PCB containing conductive traces and bonding pads and fabricated of a suitable dielectric material. In the particular example embodiment illustrated in the figures, the substrate  1404  is generally Y-shaped, with three arms  1406  extending radially outward from a central portion  1408 . As above, each arm  1406  of the substrate  1404  can be provided with at least three conductive pads or standoffs  1410 , e.g., solder bumps, for mounting and making electrical connections with the actuator devices  200 , as described above. 
     The central portion  1408  of the substrate  1404  can include, e.g., a circular central aperture  1412  within which, for example, a lens (not illustrated) can be mounted. Additionally, the central portion  1408  can be coupled to the arms  1406  by a plurality of connector parts  1414  that are subsequently cut away to free the central portion  1408  from the pads for movement relative thereto in a manner discussed below. Additionally, the central portion  1408  can be reinforced with a laminated stiffener corresponding to shape of the central portion  1408  so as to define a lens mounting platform of the types described above in connection with  FIGS. 5H, 9 and 13 . Thus the laminated central portion/stiffener  1408  can include, for example, a central aperture corresponding the central aperture  1412  in the central portion  1408 , and three tangentially extending arms  1416 . 
     Since the manner of assembly of the six-DOF actuator assembly  1402  and its superimposition on the associated frusto-conical lens barrel  1500  described in more detail below is substantially similar to that described above in connection with  FIGS. 5A-5H , further description thereof is omitted here for the sake of brevity, except to note the following differences. 
     In particular,  FIG. 14C  illustrates a step in which the connector parts  1414  can be cut away in the areas indicated by the arrows  1418  to free the mounting platform defined by the central portion/stiffener lamination  1408  discussed above from the substrate arms  1406  for its independent movement in six DOFs relative to the substrate. In some embodiments, only the portion of connector parts  1414  radially connecting to central portion  1408  may be cut, for example, and the remaining uncut portions of connector parts  1414  may be used to support one or more electrically and/or thermally conductive traces between one or more of actuator devices  200 . 
     Further, as illustrated in, e.g.,  FIGS. 14D-14F , since the associated lens barrel  1500  is generally frusto-conical in shape, it may be desirable in some embodiments to provide flats  1502  on the lens barrel  1500 , as illustrated in  FIG. 14D , to provide convenient surfaces for the attachment of the arms  1406  of the actuator assembly  1402  to the lens barrel  1500 , e.g., with an adhesive bond. Lastly, as can be seen in  FIG. 14F , when the actuator assembly  1402  is affixed to the frusto-conical lens barrel  1500  to form the six-DOF miniature camera module  1400 , the respective out-of-plane actuators  202  of the two-DOF actuator devices  200  are disposed so as to act on the mounting platform  1408  at an angle corresponding to the slope of the sides of the camera module  1500 , rather than vertically, as in the embodiments described above in connection with, e.g.,  FIGS. 5H, 9 and 13 . 
       FIGS. 15A and 15B  are top plan and elevational cross-sectional views, respectively, of an example embodiment of the frustoconical miniature camera lens barrel  1500  of type used in the example miniature camera module  1400  of  FIGS. 14A-14F  in accordance with the present invention. As can be seen in these figures, the lens barrel  1500  comprises a frusto-conical housing  1502 , which can be fabricated of, e.g., an injection molded plastic, e.g., polyurethane, to include a plurality of stepped recesses  1504  respectively configured to receive a corresponding one of an image sensor  1506  or a plurality of fixed lenses  1508 , some of which can comprise compound lenses, forming the photographic objective of the camera module  1400 . As illustrated in  FIG. 15B , annular spacers  1510  can be used to separate and space the image sensor  1506  and lenses  1508  apart from each other at the appropriate distances, and the lenses  1508  and the image sensor  1506  can be bonded permanently in place with, e.g., a suitable adhesive. 
       FIGS. 16A and 16B  are top-and-side perspective and elevational cross-sectional views, respectively, of the miniature camera module  1400  of  FIGS. 14A-14F , shown surrounded by a concentric protective housing  1600 . In the particular embodiment illustrated, the housing  1600  has a substantially cylindrical outer circumference and a frusto-conical central bore, or lumen  1602 , having an interior surface that generally conforms to the frusto-conical outer surface of the lens barrel  1500  so as to create a protected space  1604  around the actuator devices  200  of the actuator assembly  1400 . The protective cover can comprise, e.g., an injection molded plastic, and as illustrated in  FIG. 16B , a single objective lens  1606  can be mounted on the mounting platform  1408  for movement by the actuators  200  of the actuator assembly  1400  in six DOFs. 
       FIG. 17  is a schematic cross-sectional side elevation view of another example embodiment of a miniature camera module  1700  in accordance with the present invention. As illustrated in  FIG. 17  the example camera module  1700  comprises first and second actuator assemblies  1702  and  1704  of the type discussed above in connection with  FIGS. 14A-14F , which are disposed along an optical axis  1706  of the camera module  1700  to move corresponding ones of two lenses  1708  and  1710  respectively mounted on mounting platforms  1712  and  1714  independently of each other and relative to a plurality of fixed lenses  1716  and an image sensor  1718  disposed within the example camera module  1700  so as to effect, for example a zooming function. Either or both of the actuator assemblies  1702  can comprise either three- or six-DOF actuators of the types discussed above. As those of some skill will appreciate, the fold-down substrate technique for forming the actuator assemblies discussed above, coupled with the tapering outer surface of the frusto-conical shape of the associated lens barrel enables any practical number of independent actuator assemblies to be “staged” along the optical axis  1706  of the camera module  1700  without unduly increasing the diameter of the module. 
     In light of the foregoing description, it should be clear that many modifications, substitutions and variations can be made in and to the materials, apparatus, configurations and methods of use the multiple DOF actuator assemblies of the present disclosure, and in light of this, that the scope of the present disclosure should not be limited to that of the particular embodiments illustrated and described herein, as they are merely by way of some examples thereof, but rather, should be fully commensurate with that of the claims appended hereafter and their functional equivalents.