Membrane actuator with laterally oriented structural reinforcements to increase actuator travel

Abstract

A thin film actuator having a laterally oriented structural stiffener for increasing actuation travel caused by longitudinal curvature. The thin film actuator can be deployed within an electromechanical device such that an actuatable deflection of a top end of the actuator plate produces actuation travel. The thin film actuator can include an actuator plate that is fixed to a substantially rigid frame structure. The actuator plate projects away from the frame structure along a longitudinal axis such that the actuator plate cantilevers a distance from the frame structure along the longitudinal axis. The thin film actuator includes a piezoelectric film on a surface of the actuator plate. Activation of the piezoelectric film generates either a tensile or compressive stress at the surface, thereby inducing a bending moment that causes the actuator plate to experience longitudinal curvature and some lesser degree of lateral curvature.

Description

Background Technology

[0001] Thin-film actuators are widely used in electromechanical devices to induce controlled movement of components by applying a drive signal to a piezoelectric material. For example, microelectromechanical systems (MEMS) scanning devices modulate the angular position of a scanning mirror with extremely high accuracy by applying an external electric field to a piezoelectric film deposited on the top and / or bottom surfaces of an actuator plate mechanically coupled to the scanning mirror. When the piezoelectric film expands or contracts, mechanical stress is induced at any surface of the actuator plate to which the piezoelectric film is attached. This mechanical stress generates a bending moment within the actuator plate, which causes a longitudinal curvature that results in actuator travel (e.g., tip deflection in the vertical direction). The amount of actuator travel is inversely related to both the second planar area moment (also referred to herein as “moment of inertia” or “area moment of inertia” or “bending stiffness”) of a planar section taken along the longitudinal axis and the Young's modulus of the actuator plate material, and is proportional to the square of the actuator length in the longitudinal direction. The longitudinal direction specifically refers to the direction in which the actuator plate extends from the frame cantilever. Furthermore, the transverse direction refers to the direction orthogonal to the longitudinal direction and lying in a plane with the top surface of the actuator plate. Finally, the vertical direction is orthogonal to both the longitudinal and transverse directions.

[0002] Importantly, the smaller the moment of inertia of the actuator plate at various planar sections along the longitudinal axis, the greater the actuator stroke that will be generated by any particular bending moment within the actuator plate. Sufficiently high actuation force is also required, depending on the device design. Generating sufficient actuator stroke and force is a challenge in many thin-film actuator applications. Therefore, actuator plates are often designed to be thin and flat in height, as these geometries minimize the moment of inertia along the longitudinal axis, thereby increasing the longitudinal curvature of the actuator plate for any particular bending moment.

[0003] Unfortunately, the mechanical actuation sensed in a typical actuator plate via activation of the piezoelectric film results in a degree of lateral curvature, which causes a rapid increase in the moment of inertia of the actuator plate along the longitudinal axis. Since actuator stroke is inversely related to this moment of inertia, this lateral curvature has a performance hindering effect on reducing actuator stroke and force. That is, the increased lateral curvature tends to increase the stiffness of the actuator plate along the longitudinal axis, which in turn reduces the particularly desirable pattern of longitudinal curvature in order to generate actuator stroke.

[0004] Regarding these and other considerations, the content presented in this article is publicly available. Summary of the Invention

[0005] The technology described herein provides a thin-film actuator with laterally oriented structural reinforcements (e.g., ribs) to increase the actuation stroke generated by a bending pattern associated with longitudinal curvature. Embodiments of the thin-film actuator described herein are deployed within an electromechanical device such that an actuable deflection of the top of the actuator plate in the vertical direction generates the actuation stroke. Typically described, the thin-film actuator may include an actuator plate mechanically coupled to a generally rigid frame structure. The actuator plate cantilevers a distance from the frame structure along a longitudinal axis. The thin-film actuator includes a piezoelectric film on the surface of the actuator plate. Activation of the piezoelectric film generates tensile or compressive stress at the surface, thereby inducing an internal moment that causes the actuator plate to bend with a degree of longitudinal curvature (and a smaller degree of lateral curvature).

[0006] As described herein, the greater the amount of longitudinal curvature induced in the actuator plate, the greater the effective actuator stroke of the thin-film actuator. Therefore, the thin-film actuator may also include multiple laterally oriented structural reinforcements to reduce or substantially eliminate the amount of lateral curvature induced in the actuator plate during activation of the piezoelectric film. Mitigating this bending mode associated with lateral curvature tends to prevent an increase in the moment of inertia of the longitudinally acquired planar cross-section. Therefore, mitigating the bending mode associated with lateral curvature serves as an effective mechanism for increasing the bending mode associated with longitudinal curvature (e.g., the desired curvature mode, as it corresponds to actuator stroke).

[0007] To illustrate this point, consider that many piezoelectric materials expand and contract isotopically, and therefore, when activated (e.g., by applying a driving signal or voltage), stress is generated in substantially all directions. This isotopically induced stress can be described with respect to both the longitudinal and transverse components of the stress that induce longitudinal and transverse curvature, respectively. For the purpose of direct illustration, it is assumed that longitudinal curvature is desirable in the sense that a greater longitudinal curvature results in a greater braking stroke. It will be appreciated that the amount of longitudinal curvature decreases as bending stiffness increases along the longitudinal axis. Since bending stiffness along the longitudinal axis tends to increase due to transverse curvature, reducing transverse curvature is an effective means of increasing the desired bending modes associated with the longitudinal curvature that generate actuable stroke. To this end, various embodiments of the thin-film actuators described herein include structural reinforcements oriented laterally to increase the actuator plate's resistance to the bending modes associated with transverse curvature. Specifically, the laterally oriented structural reinforcements reduce (or even substantially eliminate) the amount of transverse curvature caused by the transverse stress components.

[0008] In an exemplary embodiment, the microelectromechanical system (MEMS) actuation device includes an actuator plate, a piezoelectric film deposited on a top surface of the actuator plate, and a plurality of structural reinforcements protruding from a bottom surface of the actuator plate opposite to the top surface. An exemplary piezoelectric film may be formed of lead zirconate titanate (PZT). A base of the actuator plate is mechanically coupled to a frame structure, and the actuator plate protrudes away from the frame structure along a longitudinal axis extending from the base to the top of the actuator plate. In this way, the actuator plate cantilevered from the frame structure.

[0009] Activation of the piezoelectric membrane via a drive signal (e.g., a voltage applied with extremely high accuracy by a controller) causes the piezoelectric membrane to expand and / or contract in a plane. This deformation of the piezoelectric membrane generates compressive and / or tensile stresses with both longitudinal and transverse components, typically equal to each other, and thus referred to as a bidirectional stress state. The longitudinal component can induce longitudinal curvature, as described above, which directly corresponds to the actuable tip deflection (e.g., actuator stroke). The greater the amount of induced longitudinal curvature, the greater the actuable stroke of the MEMS actuator. Furthermore, the amount of this longitudinal curvature tends to decrease as the moment of inertia (bending stiffness) of the MEMS actuator increases at a planar section taken along the longitudinal axis. Since transverse curvature tends to increase bending stiffness along the longitudinal axis, minimizing the bending modes associated with transverse curvature is likely desirable. Multiple structural reinforcements protruding from the bottom surface of the actuator plate are included to prevent such bending modes associated with transverse curvature.

[0010] In some embodiments, the nominal thickness of the actuator plate is at least three times greater than the nominal thickness of the piezoelectric film. Furthermore, the individual structural reinforcement can protrude from the actuator plate by a distance at least three times the nominal thickness of the actuator plate. As a specific but non-limiting example, the actuator plate may have a nominal thickness of 35 micrometers (35 μm) (i.e., the design thickness), while the piezoelectric film may have a nominal thickness of less than 5 micrometers (5 μm). Additionally, the individual structural reinforcement can extend from the bottom surface of the actuator plate by more than 100 micrometers (100 μm). Therefore, it can be appreciated that in some embodiments, the individual reinforcement can protrude to a height greater than 100 times the nominal thickness of the piezoelectric film.

[0011] These and various other features will become apparent from the following detailed description and a review of the accompanying drawings. This summary is provided to introduce a selection of concepts in a simplified form, which are further described in the detailed description below. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to limit the scope of the claimed subject matter. Furthermore, the claimed subject matter is not limited to implementations that address any or all of the shortcomings mentioned in any part of this disclosure. Attached Figure Description

[0012] Refer to the accompanying drawings for detailed description. In the figures, the leftmost digit of a reference numeral indicates the figure in which the reference numeral first appears. The same reference numeral in different figures indicates similar or identical items. References to individual items among multiple items can be made using a reference number enclosed in parentheses (and / or without parentheses) with another number. General references to items can be made using specific reference numerals that do not have an alphabetical sequence.

[0013] Figure 1 An exemplary microelectromechanical system (MEMS) scanning device is illustrated, which includes a set of thin-film actuators, each of which includes a laterally oriented structural reinforcement and is actuable to rotate a scanning mirror about a rotation axis.

[0014] Figure 2 The illustration shows a detailed view of a MEMS scanning device that displays the top portion of an individual thin-film actuator.

[0015] Figure 3A The illustration shows a MEMS scanning device in a neutral state, where the thin-film actuator is in an equilibrium position.

[0016] Figure 3B The illustration shows a bent state. Figure 3A A side view of a MEMS scanning device, in which a thin-film actuator has been actuated to induce the scanning mirror to rotate about a rotation axis.

[0017] Figure 4A The illustration shows a thin-film actuator in a synclastic (e.g., bidirectional) bending state due to stress being applied to the surface of the thin-film actuator by activating the actuating material deposited on the surface.

[0018] Figure 4B An exemplary cross-section of a thin-film actuator is shown in the figure, taken at a section orthogonal to the longitudinal axis.

[0019] Figure 5AThe illustration shows a thin-film actuator including a laterally oriented structural reinforcement that causes the thin-film actuator to bend in a more monoclavable (e.g., unidirectional) manner than that shown in FIG4 due to stresses similar to those applied to the thin-film actuator of FIG4.

[0020] Figure 5B The diagram shows Figure 5A An exemplary cross-section of the thin-film actuator is obtained along a section orthogonal to the longitudinal axis and not intersecting with any laterally oriented structural reinforcements.

[0021] Figure 5C The diagram shows Figure 5A An exemplary cross-section of the thin-film actuator is obtained along a section orthogonal to the transverse axis and intersecting with a laterally oriented structural reinforcement.

[0022] Figure 6A An isometric view of an exemplary microelectromechanical system (MEMS) actuation device is illustrated.

[0023] Figure 6B The diagram shows Figure 6A A top view of a MEMS actuation device.

[0024] Figure 6C The diagram shows Figure 6A and Figure 6B MEMS actuator along Figure 6B The cross-sectional view obtained by line AA.

[0025] Figure 7A An isometric view of an alternative embodiment of an exemplary microelectromechanical system (MEMS) actuation device with a nonlinear vertical axis is illustrated.

[0026] Figure 7B The diagram shows Figure 7A A top view of a MEMS actuation device.

[0027] Figure 8 An alternative embodiment of an exemplary microelectromechanical system (MEMS) actuation device is illustrated.

[0028] Figure 9 The diagram illustrates a block diagram of an exemplary control system for a microelectromechanical system (MEMS) component, which includes one or more actuators having various geometric details (e.g., structural reinforcements) as described herein.

[0029] Figure 10 An exemplary scanning beam display system is illustrated, in which various embodiments of the thin-film actuators described herein can be deployed. Detailed Implementation

[0030] This detailed description describes a thin-film actuator having a laterally oriented structural reinforcement for increasing actuation stroke. Generally, embodiments of the thin-film actuator described herein can be deployed within electromechanical devices such that an actuable deflection of a portion of the actuator plate in a desired direction corresponds to effective actuator stroke. For example, the thin-film actuator may include an actuator plate and / or a deposited actuating film mechanically coupled to a substantially rigid frame structure and protruding away from the substantially rigid frame structure along a longitudinal axis. In this way, the actuator plate cantilevered a distance from the frame structure along this longitudinal axis. The thin-film actuator may also include a piezoelectric film on the top surface of the actuator plate. Activation of the piezoelectric film generates tensile or compressive stress on the top surface, thereby inducing a bending moment that causes the actuator plate to deform according to a longitudinal curvature, causing the tip of the actuator to bend upward and / or downward (e.g., in a positive or negative vertical direction), thereby generating actuator stroke. In some embodiments described herein, the greater the amount of longitudinal curvature that occurs, the greater the effective actuator stroke of the thin-film actuator. Therefore, the thin-film actuator may also include a plurality of laterally oriented structural reinforcements to reduce or substantially eliminate the amount of lateral curvature that occurs by increasing bending stiffness along the lateral axis. Reducing this lateral curvature tends to prevent the bending stiffness from increasing along the longitudinal axis and thus serves as an effective mechanism for increasing the bending patterns associated with the longitudinal curvature (e.g., the desired bending / curvature pattern, as it corresponds to the actuator stroke).

[0031] To illustrate this, consider the combined bending modes that occur when the activation of the piezoelectric film induces mechanical stress on the surface of the actuator plate. Assuming the mechanical stress comprises both longitudinal and transverse components, it will be appreciated that these longitudinal and transverse stress components will induce bending modes associated with longitudinal curvature and transverse curvature, respectively. As described above, the bending mode associated with longitudinal curvature is desirable because a greater longitudinal curvature results in a greater actuation stroke. That is, the greater the longitudinal curvature induced in the actuator plate, the further the tip of the actuator plate deflects. As further described above, the amount of longitudinal curvature decreases as the bending stiffness increases along the longitudinal axis. Since the bending stiffness along the longitudinal axis tends to increase due to transverse curvature, reducing or eliminating transverse curvature can be used as an effective means of increasing the amount of achievable longitudinal curvature (and therefore, actuation stroke). To this end, various embodiments of the thin-film actuators described herein include substantially transversely oriented structural reinforcements to reduce (or substantially eliminate) transverse curvature by increasing the bending stiffness of the actuator plate along the transverse axis. In this way, structural stiffeners that are essentially lateral reduce or essentially eliminate the amount of lateral curvature caused by lateral stress components.

[0032] The techniques disclosed herein are widely applicable to various schemes for preventing the moment of inertia of the actuator plate along the longitudinal axis (“I”). z The lateral curvature of the actuator plate is unintentionally increased due to the drive signal causing this curvature. Many aspects of the techniques disclosed herein are described in the specific context of applying laterally oriented structural reinforcements to the underside of one or more actuator plates. These actuator plates can be coupled to a scanning mirror of a microelectromechanical system (MEMS) scanning device and induce an angle rotation into said scanning mirror. While the techniques disclosed herein are not necessarily limited to such embodiments, an understanding of various aspects of the techniques disclosed herein is readily available by discussing examples in this specific context of a MEMS scanning device. However, the concepts described herein can be applied to many other scenarios to improve actuable stroke and / or force in piezoelectrically actuated MEMS devices.

[0033] Turn now Figure 1 The illustration shows an exemplary microelectromechanical system (MEMS) scanning device 100 (also referred to herein as a MEMS scanner) having one or more thin-film actuators 102 actuated to rotate a scanning mirror 108 about a rotation axis 110. For example, individual thin-film actuators in the thin-film actuators 102 may have piezoelectric films (such as those on one or more surfaces) deposited thereon. Figure 3A (As shown in the diagram). For example, thin-film actuator 102 may each comprise a thin (e.g., 3 micrometers "3 μm") layer of lead zirconate titanate (PZT), a material exhibiting a significant piezoelectric effect, deposited on its top and / or bottom surfaces. As described above, activation of the piezoelectric film on any surface on which it is deposited in an individual thin-film actuator 102 induces tensile or compressive mechanical stresses (e.g., in kg × m²). -1 ×s -2 The mechanical stress (measured in Pascals, Pa) induces a bending moment (e.g., measured in Newton-meters per beam width) within the actuator plate 104. As described above, a component of this mechanical stress results in an amount of longitudinal curvature (i.e., bending about the transverse axis). In the illustrated embodiment, this bending pattern associated with longitudinal curvature is desirable because the achievable amount of longitudinal curvature determines the achievable amount of actuator stroke. Furthermore, the greater the achievable actuator stroke, the greater the achievable angular rotation of the scanning mirror 108 about the rotation axis 110.

[0034] Specifically, as illustrated, the scanning mirror 108 is suspended on the frame structure 112 via a first torsion beam flexure 114 (1) and a second torsion beam flexure 114 (2), wherein each torsion beam flexure is mechanically coupled to the opposite side of the scanning mirror 108. In the illustrated embodiment, each of the two torsion beam flexures 114 is mechanically coupled to a pair of thin-film actuators 102. Specifically, as in Figure 1 As illustrated, the first torsion beam flexure 114(1) is mechanically coupled to the top ends of both the first thin-film actuator 102(1) and the second thin-film actuator 102(2) via a lever arm 116 extending laterally (i.e., in a direction generally parallel to the transverse axis). Similarly, the second torsion beam flexure 114(2) is also mechanically coupled to both the third thin-film actuator 102(3) and the fourth thin-film actuator 102(4) via a lever arm extending laterally. Those skilled in the art of MEMS actuator design will recognize that the thin-film actuator 102 can be shared with these other system components and coupled to the scanning mirror 108, the torsion beam flexure 114, and / or the frame structure 112 via a continuous silicon film layer between the thin-film actuator 102 and these other system components.

[0035] Regarding the angular position of the modulated scanning mirror 108, a drive signal can be provided to actuate the first thin-film actuator 102(1) and the second thin-film actuator 102(2) in a relatively vertical direction (e.g., to change shape in a controlled manner, wherein the portion of the actuator plate coupled to the lever arm deflects), thereby inducing a torque on the first torsion beam flexure 114(1). The torque generated by each actuator can be in the same direction about the rotation axis 110 (e.g., clockwise or counterclockwise). Simultaneously, additional drive signals can also be provided to actuate the third thin-film actuator 102(3) and the fourth thin-film actuator 102(4) in a relatively vertical direction to induce additional torque on the second torsion beam flexure 114(2). These torques ultimately result in a degree of torsional deformation induced in the first torsion beam flexure 114(1) and / or the second torsion beam flexure 114(2). It will be recognized that the first thin-film actuator 102(1) and the fourth thin-film actuator 102(4) can be actuated in a consistent manner in the first vertical direction, while the second thin-film actuator 102(2) and the third thin-film actuator 102(3) can also be actuated in a consistent manner in the second “opposite” vertical direction.

[0036] Since the scanning mirror 108 is suspended from the frame structure 112 via the torsion beam flexure 114, the torsional deformation of the torsion beam flexure 114 causes the scanning mirror 108 to rotate angularly about the rotation axis 110. Therefore, activation of the thin-film actuator 102 causes the scanning mirror 108 to rotate relative to the frame structure 112 about the rotation axis 110. The actuable deflection at the connection point between the actuator plate 104 and the lever arm 116 corresponds to the effective actuator stroke for the thin-film actuator 102. As described above, in some applications, it may be desirable to increase this effective actuator stroke. For example, increasing the actuator stroke can increase the range of angles into which the MEMS scanning device 100 can actuate the scanning mirror 108.

[0037] As in Figure 1 As illustrated, an individual thin-film actuator in thin-film actuator 102 may have one or more structural reinforcements 118. The structural reinforcements 118 may be substantially laterally oriented, i.e., each reinforcement extends substantially parallel to a transverse axis (e.g., “Y”) corresponding to the actuator plate 104, and the structural reinforcement 118 protrudes from the actuator plate 104. In this way, the structural reinforcements 118 are included to mitigate (e.g., partially reduce or substantially eliminate) the transverse curvature, which is a result of mechanical stress induced during the activation of the piezoelectric film. Specifically, the laterally oriented structural reinforcements 118, as protrusions from the actuator plate 104, increase the moment of inertia (Ig) of the actuator plate 104 along the transverse axis corresponding to the axis from which the structural reinforcement 118 protrudes from the actuator plate 104. z Therefore, the laterally oriented structural reinforcement 118 serves as an effective means of reducing the lateral curvature of the actuator plate 104.

[0038] Conversely, along most of the longitudinal axis (X) corresponding to the actuator plate 104, the laterally oriented structural reinforcement 118, as a protrusion from the actuator plate 104, does not significantly increase the moment of inertia (I) when its total width is narrow or small compared to the length of the actuator plate 104. z For example, for most of the cross-section of the thin-film actuator 102 orthogonal to the longitudinal axis, the structural reinforcement 118 will have a moment of inertia (I) about the thin-film plate 104 (e.g., actuator arm). zThere is no effect (except, of course, on those cross sections orthogonal to the longitudinal axis and intersecting one of the structural stiffeners 118). Therefore, although used as an effective means of reducing lateral curvature, the laterally oriented structural stiffener 118 does not directly suppress the longitudinal curvature of the actuator plate 104. Furthermore, as described in more detail with respect to Figures 4 and 5, the inclusion of the structural stiffener 118 tends to increase the mononuclear nature of the bending of the thin-film actuator 102. This is not to say that the inclusion of the structural stiffener 118 achieves perfect mononuclear bending, but rather that the inclusion of the structural stiffener 118 increases the amount of longitudinal curvature and / or reduces the amount of lateral curvature. For example, the lateral orientation of the structural stiffener 118 reduces the degree of lateral curvature induced during activation of the thin-film actuator 102, which in turn reduces the moment of inertia (I) during activation. z The amount of increase along the longitudinal axis (although a slight increase may still occur) in turn increases the achievable tip deflection of the thin-film actuator 102.

[0039] Turn now Figure 2 The illustration shows a detailed view of the MEMS scanning device 100, which shows portion 202 of the fourth thin-film actuator 102(4). Figure 2 The detailed view shown corresponds to the view in Figure 1 Detail A is circled in the middle. (As shown in...) Figure 2 As illustrated, a portion 202 of actuator plate 104 is connected to flexible lever arm 116 in a manner that indirectly couples scanning mirror 108 to fourth thin-film actuator 102 (4). The actuable deflection of this portion 202 of actuator plate 104 defines the achievable actuator stroke 204. In the illustrated embodiment, the portion 202 of actuator plate 104 is located at or substantially near the top of the fourth thin-film actuator 102 (4). However, the portion 202 of actuator plate 104 for controllable deflection to achieve actuator stroke 204 can be located elsewhere along the longitudinal axis. For example, the portion 202 can be located relatively closer to the base of actuator plate 104, which is mechanically coupled to frame structure 112 and from which actuator plate 104 protrudes.

[0040] In the illustrated embodiment, at least a first structural reinforcement 118(1) and a second structural reinforcement 118(2) protrude from the bottom surface 206 of the actuator plate 104. Furthermore, each of the structural reinforcements 118 is substantially parallel to the transverse axis (Y). As described herein, the inclusion of these structural reinforcements 118, laterally oriented on the surface of the actuator plate 104 of the cantilevered thin-film actuator, has been determined to significantly increase the achievable tip deflection, which, as described herein, can directly correspond to the actuator stroke 204.

[0041] As a concrete example, consider a baseline scenario for a thin-film actuator mechanically fixed to a frame structure at a base having a first width of approximately two millimeters relative to the transverse axis and protruding approximately three and a half millimeters from the frame structure along the longitudinal axis to a apex having a second width of approximately half a millimeter. It has been empirically determined that, compared to a baseline embodiment without reinforcement, including three laterally oriented structural reinforcements at different distances along the longitudinal axis (e.g., as in…) Figure 1 and Figure 2 (As illustrated in the figure) this results in a significant gain (e.g., 1.60% or 60% gain) in achievable tip deflection, as a preventative effect against the increase in moment of inertia (I) along the longitudinal axis during activation due to unintentional / undesirable lateral curvature. z The direct result of ).

[0042] Figure 3A and Figure 3B Various flexural states of an exemplary MEMS scanning device 100 according to one or more embodiments described herein are illustrated. Specifically, as described herein, during operation of the MEMS scanning device 100, a thin-film actuator 102 induces torsional deformation in the torsion beam flexure 114 to cause the scanning mirror 108 to rotate about the rotation axis 110. The degree or amount of achievable torsional deformation is a direct result of the amount of actuator stroke 204 achievable by the thin-film actuator 102. Similarly, the degree or amount of achievable angular rotation of the scanning mirror 108 is a direct result of the amount of achievable torsional deformation.

[0043] Figure 3A The illustration shows a MEMS scanning device 100 in a neutral state, where thin-film actuators 102 are in an equilibrium position corresponding to the scanning mirror 108 being substantially parallel, or potentially even coplanar, with the top surface 302 of the frame structure 112. In the illustrated embodiment, individual thin-film actuators within the thin-film actuators 102 comprise corresponding thin-film layers of actuating material 304. As an example, each thin-film actuator 102 may comprise a thin layer (e.g., 3 micrometers "3 μm") of lead zirconate titanate (PZT), a material exhibiting a significant piezoelectric effect. For illustrative purposes, specific areas of the thin-film actuators 102 covered by the actuating material 304 are shown using a shading pattern. Figure 3A The neutral state illustrated in the figure can correspond to a static or equilibrium state, in which no driving signal is currently applied to the actuating material 304, and therefore no internal torque is induced in the thin film actuator 102.

[0044] In some embodiments, each thin-film actuator in the thin-film actuator 102 includes an actuator plate 104 (in... Figure 3A Below the actuating material in the middle— Figure 1 and Figure 2 (indicated by the Chinese character), the actuator plate 104 is formed of a selected material that extends continuously through one or more of the torsion beam flexure 114, the scanning mirror 108, and the frame structure 112. For example, the scanning mirror 108 may correspond to a portion of a thin (e.g., 35 micrometers "35 μm") plate of silicon 100 on which some mirror 306 or film is deposited; the thin film actuator 102 may correspond to a portion of the thin plate on which a thin (e.g., 3 micrometers "3 μm") layer of lead zirconate titanate (PZT) is deposited; and the frame structure 112 may correspond to a portion of the thin plate covering / coupled to a substantially thicker plate (e.g., 400 micrometers "400 μm") of silicon 100 to provide frame-like rigidity. In such an embodiment, since the boundary between the actuator plate 104 and the lever arm 116 is a continuous material, an important design consideration is to provide sufficient mechanical compliance to the tip 308 of the actuator plate 102 during the stroke of the thin-film actuator 102, which induces the rotational throwing of the scanning mirror 108. In some embodiments, such as illustrated herein, this mechanical compliance is achieved by tapering the actuator plate 104 toward the tip 308. In this way, substantially mononuclear bending can occur toward the base(s) 310 of the thin-film actuator 102, while toward the tip 308, the actuator plate 104 is compliant and will undergo torsional deformation due to the tension from the lever arm 116.

[0045] In the illustrated embodiment, the actuator plate is shown as a cantilever from a substantially rigid frame structure having a greater thickness relative to the actuator plate. For example, the frame structure may have a nominal thickness of 450 micrometers, while the actuator plate may have a nominal thickness of 35 micrometers, and the nominal thickness of the reinforcement is approximately five times that of the actuator plate. In some embodiments, the actuator plate and the rigid frame structure may have the same nominal thickness. For example, the frame structure may have a nominal thickness of 35 micrometers, and the actuator plate may also have a nominal thickness of 35 micrometers. In such embodiments, the actuable portion or arm corresponds to or is defined by a region of continuous material on which piezoelectric material is deposited (which constitutes both the rigid frame structure and the actuator plate).

[0046] Turn now Figure 3B The illustration shows a side view of a MEMS scanning device 100 in a bent state, wherein a thin-film actuator 102 has been actuated to induce the scanning mirror 108 to rotate about a rotation axis 110. (As shown in...) Figure 3BAs shown, the fourth thin-film actuator 102 (4) has been actuated upwards (i.e., raised above the top surface 302 of the frame structure 112), meaning that a longitudinal curvature of a radius p starting from the curvature center O' is induced in the actuator. As a result, the fourth thin-film actuator 102 (4) applies an upward actuating force to the lever arm 116, which transmits this force as torque to the torsion beam flexure 114 (hidden behind the frame structure 112). Since there are four thin-film actuators 102 in the MEMS scanning device 100, each of these actuators can be actuated uniformly to rotate the scanning mirror 108 about the rotation axis 110. Those skilled in the art of MEMS scanner design will appreciate that, during operation, the drive signal can be continuously applied and adjusted to drive the scanning mirror 108 with a desired waveform and frequency, or to maintain it at a desired angle between a positive displacement angle (φ) and a negative displacement angle (φ).

[0047] Turn now Figure 4A The figure illustrates a thin-film actuator 400 in a unidirectional bending state due to stress applied to surface 402 by activating an actuating material (e.g., PZT) deposited on surface 402. As illustrated, the unidirectional bending state can be characterized by the principal curvatures of surface 402 having the same sign or even magnitude. In other words, the centers of curvature for both the line indicating longitudinal curvature and the line indicating transverse curvature are on the same side of surface 402 (i.e., below the surface in the bending state shown in Figure 4). As used herein, the term "unidirectional bending" refers to a bending mode in which the bending surface is characterized by bending in both directions at any given time, and in which each bending direction is away from the initial neutral plane 404. As illustrated, the initial plane 404 can be defined by the transverse (Y) and longitudinal (X) axes of the thin-film actuator 400.

[0048] Regarding the lateral curvature that hinders the performance of the thin-film actuator 400, it is assumed that the thin-film actuator 400 is deployed in a scenario where the maximum longitudinal curvature is desired. In these cases, the moment of inertia (I) of the thin-film actuator 400 along the longitudinal axis is... z An increase in transverse curvature may hinder the desired maximization of longitudinal curvature. This is because transverse curvature tends to increase the moment of inertia (I) of the thin-film actuator 400 at various cross-sections along (and orthogonal to) the longitudinal axis. z Therefore, the lateral curvature shown in Figure 4 may hinder the performance of the thin film actuator 400.

[0049] Turn now Figure 4B The illustration shows an exemplary cross-section of the thin-film actuator 400 taken at section 406. At the illustrated cross-section, the moment of inertia (I) of the actuator plate is... zThe moment of inertia (I) will tend to increase with increasing transverse curvature. Furthermore, for any given cross-sectional area taken along the longitudinal axis, the moment of inertia calculated about the corresponding neutral axis (I0) will... z It can be determined based on the following equation 1:

[0050] I z =∫ A z 2 dA Equation 1

[0051] To address the problem of bending in one direction hindering (e.g., reducing) actuator travel caused by bending in another direction, the currently disclosed technology aims to provide a thin-film actuator that is highly resistant to one bending mode / direction while having appropriate compliance / flexibility to bending in another bending mode / direction.

[0052] Turn now Figure 5A The figure illustrates a thin-film actuator 500, which includes a laterally oriented structural reinforcement 504 and is in a state of “substantially” mononuclear bending due to stresses similar to those applied in Figure 4. As illustrated, the mononuclear bending state can be characterized by the fact that the relative amount of bending in one direction is significantly greater than the amount of bending in another perpendicular direction. It will be appreciated that, in the illustrated embodiment, the amount of bending associated with the longitudinal curvature is substantially greater than the amount of bending associated with the lateral curvature. Therefore, the bending state illustrated in Figure 5 can be aptly described as a state of “substantially” (though not “perfectly”) mononuclear bending.

[0053] Turn now Figure 5B An exemplary cross-section of a thin-film actuator 500 including a laterally oriented structural reinforcement 504 is illustrated. Figure 5B The cross section is obtained at section 506. Since this particular cross section does not fall directly on one of the laterally oriented structural stiffeners 504, these stiffeners will not affect the moment of inertia (I0). z Furthermore, since the relatively small number of cross sections obtained at equal intervals along the longitudinal axis will fall directly on the transversely oriented structural stiffeners 504, these stiffeners will not significantly increase the bending stiffness along the longitudinal axis.

[0054] Turn now Figure 5C The illustration shows an exemplary cross-section of the thin-film actuator 500 taken at section 508. As illustrated, compared to the thin-film actuator 400 without laterally oriented structural reinforcements, the cross-section taken along the lateral (longitudinal?) axis will have an increased moment of inertia (I) along the lateral axis. z The lateral curvature is reduced because the lateral direction of the structural reinforcement 504 is intersected in a manner that allows it to intersect with the transversely oriented structural reinforcement 504. Figure 5B and Figure 4BThe visual comparison reveals that the relative amount of lateral curvature of the reinforcing member 504 in the actuator 500 is smaller than that in the actuator 400. This reduction in lateral curvature serves to prevent an increase in bending stiffness along the longitudinal axis, and thus to increase actuator stroke.

[0055] Now specifically for reference Figure 6A An isometric view of an exemplary microelectromechanical system (MEMS) actuation device 600 is illustrated. As shown, the MEMS actuation device 600 includes an actuator plate 602 and a plurality of structural reinforcements 604 projecting from a first surface 606 of the actuator plate 602. In the illustrated embodiment, the MEMS actuation device 600 includes three individual structural reinforcements 604, each of which is substantially perpendicular to the linear longitudinal axis Axis. Long The linear longitudinal axis extends from the base 608 of the actuator plate 602 coupled to the frame structure 610 to the top 612 of the actuator plate 602.

[0056] Figure 6B The diagram shows Figure 6A A top view of a MEMS actuation device. Figure 6C The diagram shows Figure 6A and Figure 6B MEMS actuator along Figure 6B The cross-sectional view obtained from line AA. (As shown in...) Figure 6C As shown, the MEMS actuation device 600 includes an actuation material 614, such as, for example, a piezoelectric film on the side opposite to the side protruding from the structural reinforcement 604.

[0057] As in Figure 6A and Figure 6B As illustrated, the longitudinal axis is depicted as substantially parallel to one side of the actuator plate 602 and slightly offset, while the transverse axis is depicted as perfectly orthogonal to the longitudinal axis. However, other orientations and / or positions of the longitudinal axis are contemplated and are within the scope of this disclosure. For example, in some embodiments, the longitudinal axis may be defined as parallel to either side of the actuator plate 602. As another example, in some embodiments, the longitudinal axis may be defined as substantially orthogonal to the cantilever support. As another example, in some embodiments, the longitudinal axis may be defined as substantially collinear with the centerline of the actuator plate 602. As another example, in some embodiments, the longitudinal axis may be defined as substantially orthogonal to the cantilever support.

[0058] Special Reference Figure 6CThe actuator plate 602 may have a first nominal thickness T1, while the structural reinforcement 604 may protrude from the actuator plate 602 by a second nominal thickness T2. Furthermore, the actuating material 614 may have a third nominal thickness T3 (note: since the third nominal thickness T3 is relatively small in proportion to the first and second nominal thicknesses, the third thickness T3 is...). Figure 6C (Not graphically represented), which may differ from one of the first nominal thickness and the second nominal thickness, or both.

[0059] In some embodiments, the first nominal thickness T1 of the actuator plate may be at least five times greater than the third nominal thickness T3, and the second nominal thickness T2 may be at least twenty times greater than the third nominal thickness T3. For example, in a particular embodiment, the first nominal thickness T1 of the actuator plate may be 35 micrometers (35 μm), while the third nominal thickness T3 may be less than 5 micrometers (5 μm), and the second nominal thickness T2 may be greater than 140 micrometers (140 μm). In some embodiments, the length L of the MEMS actuator device 600 may be 80 times greater than the first nominal thickness T1 of the actuator plate 602. That is, the MEMS actuator device 600 may have an aspect ratio of 1 / 80 or even greater. In some embodiments, the length of the MEMS actuator device 600 may be fifty times greater than the first nominal thickness T1 of the actuator plate 602. That is, the MEMS actuator device 600 may have an aspect ratio of 1 / 50 or even greater. In some embodiments, the MEMS actuator 600 can extend to a length that is one thousand times greater than the first nominal thickness T1 of the actuator plate 602. That is, the MEMS actuator 600 can have an aspect ratio of 1 / 1000 or even greater. In some embodiments, the MEMS actuator 600 can extend to a length L that is ten times greater than the first nominal thickness T1 of the actuator plate 602. That is, the MEMS actuator 600 can have an aspect ratio of 1 / 10 or even greater.

[0060] Now specifically for reference Figure 7A The illustration shows an isometric view of an alternative embodiment of an exemplary microelectromechanical system (MEMS) actuation device 700. As illustrated, the MEMS actuation device 700 includes an actuator plate 702 and a plurality of structural reinforcements 704 projecting from a first surface 706 of the actuator plate 702. Figure 7B The diagram shows Figure 7A A top view of the MEMS actuator 700. (As shown in...) Figure 7B As shown, the MEMS actuation device 700 includes four individual structural reinforcements 704, each of which is coupled to a curved longitudinal axis Axis extending from the base 708 of the actuator plate 702 to the top 712 of the frame structure 710. LongA portion of them intersects. In some embodiments, each individual structural reinforcement 704 is substantially parallel to the transverse axis Axis. Trans The horizontal axis corresponds to the longitudinal axis (Axis) of the individual structural reinforcement and bending. Long Intersecting points

[0061] Turn now Figure 8 An alternative embodiment of an exemplary microelectromechanical system (MEMS) actuation device 800 is illustrated. Figure 8 In the illustrated embodiment, an alternative manual method is used to prevent unwanted longitudinal reinforcement due to lateral curvature. Specifically, the MEMS actuation device 800 does not include structural reinforcement to prevent lateral curvature, but instead includes one or more cutouts 802 within the actuator plate 804. The cutouts 802 effectively divide the actuator into two or more longitudinally curved narrow arms. The curvature along the lateral axis is smaller than the curvature without the cutouts 802. The reduced curvature along the lateral axis effectively reduces the degree of increase in the area moment of inertia caused by actuation. Figure 8 In the image, the shaded pattern on actuator plate 804 represents a thin piezoelectric actuation material.

[0062] Turn now Figure 9 The diagram illustrates a block diagram of an exemplary control system 900 for a microelectromechanical system (MEMS) 904, which includes one or more actuators 906 having various geometric details (e.g., structural reinforcements) as described herein. Figure 9 As illustrated herein, the control system 900 may include a controller 902 that provides drive signals 910 to one or more actuators 906, as described herein. The actuators 906 may be configured to controllably move various components of the MEMS 904. As further illustrated, the control system 900 also includes a strain sensor 908 that detects specific patterns of mechanical strain within the MEMS 904 and, in response, provides a feedback signal 912 to the controller 902. An exemplary strain sensor 908 may include a piezoresistive (PZR) sensor that converts mechanical movement of a specific portion of the MEMS 904 into an electrical signal to generate the feedback signal 912. In various embodiments, the MEMS 904 may be a component of a scanning beam display system, as described below. Figure 10 As shown and described. However, MEMS 904 can be any type of MEMS device that operates electromechanically in response to drive signal 910 and simultaneously returns feedback signal 912 to facilitate periodicity and / or continuous refinement of drive signal 910.

[0063] Turn now Figure 10This illustration depicts an exemplary scanning beam display system 1000 in which various embodiments of the thin-film actuators described herein may be deployed. As illustrated, the scanning beam display system 1000 may include a light engine 1002, which may include one or more light sources capable of emitting one or more beams 1004 toward one or more scanning mirrors 108. In some embodiments, the light engine 1002 includes multiple light sources individually capable of emitting light of a specific wavelength and / or within a specific wavelength range. As illustrated, one or more beams 1004 are incident on a MEMS 904 and reflected on one or more scanning mirrors 108. In the specifically illustrated but non-limiting scenario, the MEMS 904 includes a horizontal scanning mirror 108(H) and a vertical scanning mirror 108(V). As illustrated, one or more beams 1004 are initially incident on the horizontal scanning mirror 108(H), and then on the vertical scanning mirror 108(V), and then ultimately as a controlled output beam 1006 directed toward a display 1008. In one or more alternative embodiments, the beam(s) 1004 is initially incident on the vertical scanning mirror 108(V), and then reflected to the horizontal scanning mirror 108(H), and finally directed toward the display 1008 as a controlled output beam 1006. In one or more alternative embodiments, a single scanning mirror 108 may scan the beam(s) 1004 in both the horizontal and vertical directions.

[0064] In the illustrated embodiment, a horizontal drive signal 910(H) drives one or more actuators 102, while a vertical drive signal 910(V) drives one or more actuators 102, which may be different from those actuators 102 driven by the horizontal drive signal 910(H). Therefore, by providing the horizontal drive signal 910(H) and the vertical drive signal 910(V), the controller 902 causes the MEMS 904 to deflect one or more scanning mirrors 108, causing the output beam 1006 to generate a dual-axis scan 1010, thereby creating a display image via the display 1008. For example, the controller 902 can convert pixel information of the input image into laser modulation synchronized with the movement of the MEMS 904 to write image information as a display image based on the position of the output beam 1006 in the grating pattern and the corresponding intensity and / or color information at corresponding pixels in the image.

[0065] The controller 902 can also control various other functions of the scanning beam display system 1000. In one or more embodiments, the horizontal axis can refer to the horizontal direction of the dual-axis scan 1010, and the vertical axis can refer to the vertical direction of the dual-axis scan 1010. One or more scanning mirrors 108 can sweep the output beam 1006 horizontally at a relatively high frequency and vertically at a relatively low frequency over a portion of the scan. The result is a scanning trajectory of the laser beam 1006 that leads to the dual-axis scan 1010. The fast and slow axes can also be interchanged, such that the fast scan is in the vertical direction and the slow scan is in the horizontal direction. However, the scope of the claimed subject matter is not limited to these aspects.

[0066] In some embodiments, the scanning beam display system 1000 may be a component of a near-eye display device for implementing augmented reality (AR) / (MR, mixed reality) technology to generate a composite view including a computer-generated image superimposed on a real-world view. In these embodiments, the display 1008 may be a transparent display panel, such as, for example, a waveguide display, which includes one or more diffractive optical elements (DOEs) for coupling incident light inward into the waveguide, expanding the incident light in one or more directions for exit pupil expansion, and / or coupling incident light outward from the waveguide (e.g., toward the user's eye).

[0067] In the foregoing overview and / or detailed description, numerous specific details have been set forth to provide a thorough understanding of the claimed subject matter. However, those skilled in the art will understand that the claimed subject matter can be practiced without these specific details. In other instances, well-known methods, processes, components, and / or circuits have not been described in detail. Furthermore, the terms “coupled” and / or “connected,” along with their derivatives, may be used throughout this disclosure. In certain embodiments, a connection may be used to refer to two or more elements in direct physical and / or electrical contact with each other. Coupling may indicate that two or more elements are in direct physical and / or electrical contact. However, coupling may also indicate that two or more elements may not be in direct contact with each other, but can still cooperate and / or interact with each other. For example, “coupled” may indicate that two or more elements are not in contact with each other, but are indirectly joined together via another element or an intermediate element. Finally, the terms “on,” “covering,” and “above” may be used in the following description and claims. One or more of “on,” “covering,” and “above” may be used to indicate that two or more elements are in direct physical contact with each other. However, “on,” “covering,” and / or “above” may also describe a positional relationship between two or more elements that are not in direct contact with each other. For example, "above" can mean that one element is on top of another element, but not necessarily in direct contact with that other element (e.g., one or more others may be between the two elements).

[0068] Exemplary terms

[0069] The disclosures presented herein may be considered in accordance with the following terms.

[0070] Exemplary Clause 1, a microelectromechanical system (MEMS) actuation device, comprising: an actuator plate having a base mechanically coupled to a frame structure, wherein the actuator plate protrudes from the frame structure along a longitudinal axis extending from the base of the actuator plate to a top of the actuator plate; a piezoelectric film deposited on a first surface of the actuator plate, wherein activation of the piezoelectric film applies a bending moment to the actuator plate via a drive signal, resulting in: a lateral curvature of the actuator plate along a transverse axis, and a longitudinal curvature of the actuator plate along the longitudinal axis; and a plurality of structural reinforcements protruding from at least one of the first surface of the actuator plate or a second surface of the actuator plate opposite to the first surface, wherein individual structural reinforcements are aligned substantially parallel to the transverse axis to increase the moment of inertia resisting the lateral curvature.

[0071] Exemplary Clause 2, the MEMS actuation device described in Exemplary Clause 1, wherein the piezoelectric film has a first nominal thickness, and the actuator plate has a second nominal thickness that is at least three times greater than the first nominal thickness, and wherein the distance by which the individual structural reinforcement protrudes is at least three times the second nominal thickness.

[0072] Exemplary Clause 3, any one of Exemplary Clauses 1 to 2, wherein the plurality of structural reinforcements protrude from the second surface of the actuator plate by a distance at least twenty times the nominal thickness of the piezoelectric film.

[0073] Exemplary Clause 4, the MEMS actuation device according to any one of Exemplary Clauses 1 to 3, wherein the plurality of structural reinforcements include at least three individual reinforcements that protrude from the actuator plate at a distance of at least three times the nominal thickness of the actuator plate.

[0074] Exemplary Clause 5, any of Exemplary Clauses 1 to 4, wherein the nominal thickness of the actuator plate is at least five times greater than the nominal thickness of the piezoelectric film.

[0075] Exemplary Clause 6, any one of Exemplary Clauses 1 to 5, wherein the longitudinal curvature of the actuator plate about the transverse axis of the substantially parallel-aligned individual structural reinforcement produces an actuator stroke corresponding to the deflection of the top end of the actuator plate.

[0076] Exemplary Clause 7, any of Exemplary Clauses 1 to 6, wherein the plurality of structural reinforcements protrude from a second surface of the actuator plate opposite to the first surface on which the piezoelectric film is deposited.

[0077] Exemplary Clause 8, any of Exemplary Clauses 1 to 7, wherein the piezoelectric film is lead zirconate titanate (PZT).

[0078] Exemplary Clause 9, any one of Exemplary Clauses 1 to 8, wherein the length from the base of the actuator plate to the top of the actuator plate is at least fifty times the nominal thickness of the actuator plate, and wherein the structural reinforcement protrudes from the actuator plate by a distance at least three times the nominal thickness of the actuator plate.

[0079] Example 10, an actuation device, comprising: an actuator plate projecting from a frame structure along a longitudinal axis extending from a base of the actuator plate to a top of the actuator plate, wherein the actuator plate has a nominal thickness; a piezoelectric film, which, when activated via a drive signal, causes a combination of a lateral curvature of the actuator plate along a transverse axis and a longitudinal curvature of the actuator plate along the longitudinal axis; and one or more laterally oriented structural reinforcements substantially orthogonal to the longitudinal axis, which resist the lateral curvature of the actuator plate during activation of the piezoelectric film, thereby at least partially mitigating the increase in the area moment of inertia of the actuation device along the longitudinal axis, wherein the nominal height of each laterally oriented structural reinforcement is greater than the nominal thickness of the actuator plate.

[0080] The actuation device described in Exemplary Clause 11 and Exemplary Clause 10, wherein the nominal height of the individual laterally oriented structural reinforcement is at least three times greater than the nominal thickness of the actuator plate.

[0081] Exemplary Clause 12, the actuation device according to any one of Exemplary Clauses 10 to 11, wherein the individual laterally oriented structural reinforcement protrudes from a first surface of the actuator plate, the first surface being opposite to a second surface of the actuator plate, and the piezoelectric film is disposed on the second surface of the actuator plate.

[0082] Exemplary Clause 13, the actuation device according to any one of Exemplary Clauses 10 to 12, wherein the nominal height of the individual laterally oriented structural reinforcement protruding from the first surface is at least twenty times greater than the nominal thickness of the piezoelectric film on the second surface.

[0083] Exemplary Clause 14, the actuation device described in any one of Exemplary Clauses 10 to 13, wherein the lateral bending produces an actuator stroke corresponding to the deflection of the top end of the actuator plate.

[0084] Exemplary Clause 15, the actuation device according to any one of Exemplary Clauses 10 to 14, wherein the longitudinal axis extends linearly from the base of the actuator plate to the top of the actuator plate.

[0085] Exemplary Clause 16, the actuation device according to any one of Exemplary Clauses 10 to 15, wherein the longitudinal axis is a curved axis extending non-linearly from the base of the actuator plate to the top of the actuator plate.

[0086] Exemplary Clause 17, the actuation device according to any one of Exemplary Clauses 10 to 16, wherein the actuator plate is mechanically coupled to the scanning mirror, and wherein the amount of angular rotation induced in the scanning mirror increases directly with the increase of the longitudinal curvature of the actuation device.

[0087] Exemplary Clause 18, a system comprising: a controller for generating a drive signal; and an actuator comprising: an actuator plate extending along a longitudinal axis from a base fixed to a frame structure to a top end coupled to an actuable component; a plurality of laterally oriented reinforcements protruding from a first surface of the actuator plate; and an actuating material disposed on a second surface of the actuator plate opposite the first surface, wherein applying the drive signal to the actuating material results in a combination of a lateral curvature of the actuator plate along the transverse axis and a longitudinal curvature of the actuator plate along the longitudinal axis.

[0088] The system described in Exemplary Clause 19 and Exemplary Clause 18, wherein the longitudinal curvature produces an actuator stroke corresponding to the deflection of the top of the actuator plate.

[0089] The system described in any one of Exemplary Clause 20, Exemplary Clauses 18 to 19, wherein the nominal height of the plurality of laterally oriented reinforcements is at least twenty times greater than the nominal thickness of the actuating material.

[0090] in conclusion

[0091] Finally, although various techniques have been described in language specific to structural features and / or methodological actions, it should be understood that the subject matter defined in the appended representations is not necessarily limited to the specific features or actions described. Rather, specific features and actions are disclosed as exemplary forms for implementing the claimed subject matter.

Claims

1. A control system for microelectromechanical systems (MEMS), comprising: The controller generates drive signals; as well as Actuator, comprising: An actuator plate extends along the longitudinal axis from the base, which is fixed to the frame structure, to the top, which is coupled to the actuable component. Multiple laterally oriented reinforcing members protrude from the first surface of the actuator plate; and An actuating material is disposed on a second surface of the actuator plate opposite to the first surface, wherein the drive signal is applied to the actuating material and causes the actuator plate to bend, and wherein the bending of the actuator plate involves a combination of the transverse curvature of the actuator plate along the transverse axis and the longitudinal curvature of the actuator plate along the longitudinal axis.

2. The system according to claim 1, wherein, The longitudinal curvature produces an actuator stroke corresponding to the deflection of the top of the actuator plate.

3. The system according to claim 1, wherein, The nominal height of the plurality of laterally oriented reinforcements is at least twenty times greater than the nominal thickness of the actuating material.

4. A microelectromechanical system (MEMS) actuation device, comprising: An actuator plate having a base mechanically coupled to a frame structure, wherein the actuator plate protrudes from the frame structure along a longitudinal axis extending from the base of the actuator plate to the top of the actuator plate; A piezoelectric film is deposited on the first surface of the actuator plate, wherein activation of the piezoelectric film applies a bending moment to the actuator plate via a drive signal, resulting in: The lateral curvature of the actuator plate along the transverse axis, and The actuator plate has a longitudinal curvature along the longitudinal axis; and Multiple structural reinforcements protrude from at least one of the first surface of the actuator plate or the second surface of the actuator plate opposite to the first surface, wherein the individual structural reinforcements are substantially parallel to the transverse axis to increase the moment of inertia against the transverse curvature.

5. The MEMS actuation device according to claim 4, wherein, The piezoelectric film has a first nominal thickness, and the actuator plate has a second nominal thickness that is at least three times greater than the first nominal thickness, wherein the distance by which the individual structural reinforcement protrudes is at least three times the second nominal thickness.

6. The MEMS actuation device according to claim 4, wherein, The plurality of structural reinforcements protrude from the second surface of the actuator plate by a distance that is at least twenty times the nominal thickness of the piezoelectric film.

7. The MEMS actuation device according to claim 4, wherein, The plurality of structural reinforcements include at least three individual reinforcements that protrude from the actuator plate at a distance of at least three times the nominal thickness of the actuator plate.

8. The MEMS actuation device according to claim 7, wherein, The nominal thickness of the actuator plate is at least five times greater than the nominal thickness of the piezoelectric film.

9. The MEMS actuation device according to claim 7, wherein, The actuator plate generates an actuator stroke corresponding to the deflection of the top of the actuator plate by the longitudinal curvature of the transverse axis that is substantially parallel to and aligned with the individual structural reinforcement.

10. An actuation device, comprising: An actuator plate protrudes from the frame structure along a longitudinal axis extending from the base of the actuator plate to the top of the actuator plate, wherein the actuator plate has a nominal thickness; A piezoelectric film, when activated by a drive signal, causes a combination of the transverse curvature of the actuator plate along the transverse axis and the longitudinal curvature of the actuator plate along the longitudinal axis; and One or more laterally oriented structural reinforcements, substantially orthogonal to the longitudinal axis, resist the lateral curvature of the actuator plate during the activation of the piezoelectric film, thereby at least partially mitigating the increase in the area moment of inertia of the actuating device along the longitudinal axis, wherein the nominal height of each laterally oriented structural reinforcement is greater than the nominal thickness of the actuator plate.

11. The actuation device according to claim 10, wherein, The nominal height of the individual laterally oriented structural reinforcement is at least three times greater than the nominal thickness of the actuator plate.

12. The actuation device according to claim 10, wherein, The individual laterally oriented structural reinforcement protrudes from the first surface of the actuator plate, which is opposite to the second surface of the actuator plate, and the piezoelectric film is disposed on the second surface of the actuator plate.

13. The actuation device according to claim 12, wherein, The nominal height of the laterally oriented structural reinforcement protruding from the first surface is at least twenty times greater than the nominal thickness of the piezoelectric film on the second surface.

14. The actuation device according to claim 10, wherein, The longitudinal curvature produces an actuator stroke corresponding to the deflection of the top of the actuator plate.

15. The actuation device according to claim 10, wherein, The longitudinal axis extends linearly from the base of the actuator plate to the top of the actuator plate.

Images