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WO2014144925A1 - Commande de mouvement arqué dans des actionneurs électrostatiques - Google Patents

Commande de mouvement arqué dans des actionneurs électrostatiques Download PDF

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Publication number
WO2014144925A1
WO2014144925A1 PCT/US2014/029529 US2014029529W WO2014144925A1 WO 2014144925 A1 WO2014144925 A1 WO 2014144925A1 US 2014029529 W US2014029529 W US 2014029529W WO 2014144925 A1 WO2014144925 A1 WO 2014144925A1
Authority
WO
WIPO (PCT)
Prior art keywords
moving frame
frame
actuator
moving
angle
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US2014/029529
Other languages
English (en)
Inventor
Robert J. Calvet
Xiaolei Liu
Roman C. Gutierrez
Ankur Jain
Guiqin Wang
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
DigitalOptics Corp MEMS
Original Assignee
DigitalOptics Corp MEMS
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US13/843,107 external-priority patent/US8947797B2/en
Priority claimed from US13/843,817 external-priority patent/US8712229B2/en
Application filed by DigitalOptics Corp MEMS filed Critical DigitalOptics Corp MEMS
Priority to KR1020157028922A priority Critical patent/KR102048335B1/ko
Priority to JP2016503122A priority patent/JP6397478B2/ja
Priority to CN201480026711.4A priority patent/CN105209370B/zh
Publication of WO2014144925A1 publication Critical patent/WO2014144925A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02N—ELECTRIC MACHINES NOT OTHERWISE PROVIDED FOR
    • H02N1/00—Electrostatic generators or motors using a solid moving electrostatic charge carrier
    • H02N1/002—Electrostatic motors
    • H02N1/006—Electrostatic motors of the gap-closing type
    • H02N1/008—Laterally driven motors, e.g. of the comb-drive type
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
    • B81B3/00—Devices comprising flexible or deformable elements, e.g. comprising elastic tongues or membranes
    • B81B3/0035—Constitution or structural means for controlling the movement of the flexible or deformable elements
    • B81B3/0051—For defining the movement, i.e. structures that guide or limit the movement of an element
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
    • B81B2201/00—Specific applications of microelectromechanical systems
    • B81B2201/03—Microengines and actuators
    • B81B2201/033—Comb drives
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
    • G02B7/02—Mountings, adjusting means, or light-tight connections, for optical elements for lenses
    • G02B7/04—Mountings, adjusting means, or light-tight connections, for optical elements for lenses with mechanism for focusing or varying magnification
    • G02B7/08—Mountings, adjusting means, or light-tight connections, for optical elements for lenses with mechanism for focusing or varying magnification adapted to co-operate with a remote control mechanism

Definitions

  • One or more embodiments of the present invention relates to electrostatic actuators in general, and in particular for example, to methods and apparatus for controlling undesirable arcuate motion in them.
  • 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 electrostatic comb drives, scratch drives, and thermal drives. Microminiature electrostatic MEMS actuators can be fabricated using well known wafer- scale integrated circuit (IC) fabrication techniques, and can be used in a variety of applications. For example, electrostatic MEMS actuators can be used to move an objective lens so as to effect autofocus, zoom and image stabilization functions in miniature cameras useful in various host devices, e.g., mobile phones, computers, laptops, personal digital assistants (PDAs), surveillance cameras and the like. Accordingly, it is desirable to provide improved electrostatic MEMS actuator devices for such applications.
  • PDAs personal digital assistants
  • Electrostatic MEMS actuators are susceptible to a problem known as "arcuate motion.”
  • the comb drives of such actuators include a plurality of interdigitated fingers or teeth, portions of which are attached to a fixed stage or frame, and portions of which are attached to a moving frame. It is desirable that the teeth of the comb drives move substantially parallel to each other during operation to avoid contact, interference, "stalling,” and “chattering” problems, which in turn, requires the moving frame to move substantially parallel to the fixed frame.
  • the resilient parallel motion flexures that couple the moving frame to the fixed frame, the former necessarily experiences some second order arcuate movement relative to the latter during movement, which if not controlled, can lead to the foregoing and other problems.
  • methods and apparatus are provided for controlling arcuate motion in the comb drives of electrostatic actuators that are inexpensive, reliable and relatively easy to implement during fabrication.
  • an actuator comprises a moving frame coupled to a fixed frame by a plurality of elongated parallel motion flexures for generally parallel motion relative to the fixed frame and between an as-fabricated position and a deployed position.
  • the flexures are disposed at a first angle relative to a line extending perpendicularly to both the moving frame and the fixed frame when the moving frame is disposed in the as- fabricated position, and at a second angle relative to that same line when the moving frame is disposed in the deployed position.
  • Arcuate movement of the first frame relative to the second frame is controlled by constraining the first angle to a value that is less than about half of the sum of the first and second angles.
  • the improved actuators are particularly well suited 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, laptops, personal digital assistants (PDAs), surveillance cameras and the like.
  • electronic host devices such as mobile phones, computers, laptops, personal digital assistants (PDAs), surveillance cameras and the like.
  • Fig. IB is a top plan view of the example actuator device of Fig. 1 A, shown after being deployed for operational use in accordance with an embodiment of the disclosure.
  • Fig. 2A is an enlarged partial detail view of fixed and moving frames and associated portions of interdigitated teeth of the example actuator of Fig. 1A, showing the relative position of the frames and teeth prior to deployment in accordance with an embodiment of the disclosure.
  • Fig. 2B is an enlarged partial detail plan view of the fixed and moving frames and associated portions of interdigitated teeth of the example actuator of Fig. 2B, showing the relative position of the frames and teeth after deployment in accordance with an embodiment of the disclosure.
  • Fig. 3 is a diagrammatic illustration of a moving frame of an actuator that is moving relative to a fixed frame thereof with first order parallel motion and second order arcuate movement in accordance with an embodiment of the disclosure.
  • Fig. 4 is an enlarged partial detail view similar to Fig. 2A, showing the fixed and moving frames and associated portions of interdigitated teeth of the example actuator of Fig. IB, showing the direction of movement of the moving frame relative to the fixed frame during a closing stroke in one mode of operation in accordance with an embodiment of the disclosure.
  • Fig. 5 is a graph of the lateral displacement of the moving frame of an example actuator versus its longitudinal displacement during a full stroke of the actuator in accordance with an embodiment of the disclosure.
  • Fig. 6 is a graph of the lateral displacement of the moving frame of another example actuator versus its longitudinal displacement during a full stroke of the actuator in accordance with an embodiment of the disclosure.
  • Fig. 7 is a graph of the lateral displacement of the moving frame of an actuator configured in accordance with one or more embodiments of the present invention versus its longitudinal displacement during a full stroke of the actuator in accordance with an embodiment of the disclosure.
  • Fig. 8 is a schematic top plan view of an example electrostatic actuator in which the teeth and associated frame portions have been omitted, showing a moving frame coupled to a fixed frame by a pair of parallel motion flexures in accordance with an embodiment of the disclosure.
  • Fig. 9 is a graph similar to Fig. 7, showing the lateral displacement of the moving frame of another example actuator configured in accordance with one or more embodiments of the present invention versus its longitudinal displacement during a full stroke of the actuator.
  • This disclosure provides various embodiments of methods and apparatus for controlling arcuate movement in the comb drives of electrostatic actuators.
  • the methods and apparatus are reliable, inexpensive, and easily implemented during actuator fabrication.
  • Fig. 1 A is a top plan view of an example embodiment of an electrostatic comb drive MEMS actuator 100, shown in an as-fabricated state and prior to its "deployment" for operational use
  • Fig. IB is a top plan view of the example actuator device 100, shown after being deployed for use.
  • a moving frame 102 is coupled to a fixed frame
  • each of the fixed and moving frames 104 and 102 includes an associated plurality of electrostatic comb drive "fingers" or “teeth” 108 extending perpendicularly therefrom, which are interdigitated with each other to define electrostatic comb drive "banks.”
  • electrostatic comb drive "fingers" or “teeth” 108 extending perpendicularly therefrom, which are interdigitated with each other to define electrostatic comb drive "banks.”
  • a differential actuating voltage is selectively applied to the fixed and moving frames 104 and 102 of the comb drive banks of the actuator 100, the respective teeth 108 of the fixed and moving frames 204 and 102 move perpendicularly toward or away from each other, causing the moving frame 102 to move parallel to the fixed frame 104, i.e., in the direction of the double-headed arrow 1 10 seen in Fig. IB.
  • the actuator 100 includes three electrostatic comb drive banks.
  • the number of comb banks, as well as the number, length, width and pitch of the teeth 108 of the comb banks can vary widely, depending on the particular application at hand.
  • the interdigitated teeth 108 of the actuator 100 are shown in a "deployed" position in Fig. IB, i.e., spread apart from one another, for substantially perpendicular, rectilinear movement relative to each other.
  • the interdigitated teeth 108 of the actuator 100 are, for manufacturing reasons, initially disposed in a fully “closed” position, such that the associated fixed and moving frames 104 and 102 are spaced apart from each other by about the length of the teeth 108.
  • the actuator 100 must first be "deployed" into a configuration that enables this type of actuation.
  • this deployment can include the provision of an over-center latch 112 on the fixed frame 104.
  • the latch 112 is pivotably coupled to the fixed frame 104 with, e.g., a spring flexure 1 14.
  • An elongated deployment lever 1 16 has an outer end pivotably coupled to the fixed frame 104 with another spring flexure 118 and an inner end coupled to an end of a recurvate deployment flexure 120.
  • the other end of the deployment flexure 120 is coupled to the moving frame 102.
  • the deployment lever 116 has a surface disposed at its inner end that is configured as an inclined plane for a camming actuation of, and an over-center latching engagement with, the latch 112.
  • a pull ring 122 can be attached to the deployment flexure 120 by a spring flexure 124 disposed adjacent to the inner end of the deployment lever 116.
  • a force is applied to the pull ring 122 of the actuator 110 in the direction of the arrow 126 in Fig. 1A.
  • This causes the deployment lever 116 to rotate relative to fixed frame 104.
  • the rotation of the deployment lever 116 causes the deployment flexure 120 to urge the moving frame 102 rectilinearly and perpendicularly away from the fixed frame 104, and to the deployed position shown in Fig. IB, where the camming surface at the inner end of the deployment lever 1 16 first actuates the latch 112, i.e., causes it to pivot away from the fixed frame 104, and to then be engaged by the latch 112 so as to hold the moving frame 104 in the deployed position, as illustrated in Fig. IB.
  • Fig. 2B This, in turn, results in a deployment of the teeth 108 of the moving frame 102 to the position, indicated by the phantom line 126 in the enlarged detail view of Fig. 2B, for movement relative to the teeth 10.8 of the fixed frame 104 in the direction indicated by the double-headed arrows 128 in Fig. 2B.
  • the deployment lever 116 can then be fixed permanently, e.g., with an adhesive, to the latch 1 12 to prevent the moving frame 102 and associated moving teeth 108 from returning to their previous, "un-deployed" position shown in Fig. 1A as a result of, e.g., vibration or shock acting on the actuator device 200.
  • each of the flexures 106 comprises an elongated bar or rod having opposite ends respectively hinged by "solid hinges" 130 to the fixed and moving frames 102 and 104 for arcuate movement relative to the fixed frame 104.
  • the parallel motion flexures 106 can be approximated as linear springs, and the aspect ratio of their longitudinal vs.
  • transversal dimensions as well as their respective stiffnesses in those directions, is so large that they can be considered to be substantially rigid in the radial direction of the arcuate trajectory, i.e., the motion of the moving stage 102 will follow the arcuate trajectory of the flexures 106 rigidly.
  • the in-plane motion of the moving frame 102 relative to the fixed frame 106 will include two components, viz., the desired, first order parallel motion, as indicated by the double-headed arrow 302, and an undesirable, second order arcuate component, as indicated by the double-headed arrow 304.
  • the arcuate component 304 manifests itself as a lateral movement of the teeth 108 of the moving frame 102 relative to the teeth 108 of the fixed frame 104, i.e., in the X direction of Fig. 4.
  • a "stall" of the actuator may occur when the longitudinal force of the actuator, which is developed by a voltage difference between the frames, is less than the spring force of the parallel flexures and/or deployment flexures being applied in a direction opposite to the longitudinal force.
  • the longitudinal force may be dependent on the lateral displacement of the moving frame and/or teeth of an electrostatic drive of the actuator (e.g., as shown in Figs. 2A and 2B), such that lateral displacement reduces the longitudinal force developed by a particular voltage, and reduces it by increasing amounts as the teeth increasingly overlap (e.g., move towards the closed position illustrated in Fig. 2A).
  • a design feature may be to adapt embodiments of the present disclosure to minimize such lateral displacement (e.g., so that adjacent teeth are close to equidistant from each other throughout the comb drive) when the teeth and/or frames are near the full insertion position (e.g., Fig. 2A), for example, and/or at the longitudinal position corresponding to the highest applied voltage.
  • embodiments of the present disclosure may be adapted to shape a transduction curve of the actuator (e.g., a curve representing the responsiveness of the actuator to applied voltage, as a function of longitudinal distance and/or travel of the actuator) according to a particular application need.
  • such shaping may include fabricating an actuator according to one or more parallel flexure fabrication angles (e.g., measured away from perpendicular to the adjoining frame and/or frames, where a fabrication angle relative to the fixed frame may be different from the fabrication angle relative to the moving frame, for example), and/or according to a particular desired lateral displacement (e.g., measured between adjacent teeth relative to an equidistant position) at a deployment and/or fabrication position, for example.
  • shaping such transduction curve may be commensurate with shaping an arcuate trajectory of the actuator, as described herein.
  • the actuator has an "opening stroke," i.e., the length of movement of the moving frame 102 from the fully open or deployed position to the fully closed position, of about 130 ⁇ (130 microns, or 130X10 "6 meters) in the y direction, and that the length of the parallel motion flexures 106 is about 2.5 millimeters (mm), then deflection of the moving teeth 108 relative to the fixed teeth 108 in the lateral or x direction in Fig. 4 of only about 0.2 ⁇ (i.e., a stroke length/lateral deflection ratio of about 650/1) will adversely affect actuator performance.
  • an "opening stroke” i.e., the length of movement of the moving frame 102 from the fully open or deployed position to the fully closed position, of about 130 ⁇ (130 microns, or 130X10 "6 meters) in the y direction, and that the length of the parallel motion flexures 106 is about 2.5 millimeters (mm)
  • the arcuate motion would be as illustrated in the graph of Fig. 5.
  • the arcuate motion of the moving frame 102 will be as depicted in the graph of Fig. 7.
  • the lateral displacement of the frame 102 is balanced to either side of the nominal gap between the teeth 108, i.e., about 0.58 ⁇ on either side, thereby providing the minimum lateral deflection for a given flexure length and stroke.
  • Fig. 8 is a schematic plan view of another example electrostatic actuator 100 in which the teeth 108 and associated portions of the moving and fixed frames 102 and 104 have been omitted for purposes illustration.
  • the relevant parameters assumed for this particular example embodiment are given in the following table:
  • the as-fabricated or closed angle a c is about 0.32 times the full stroke angle a.
  • This results in the arcuate motion of the moving frame 102 illustrated in Fig. 9, wherein it can be seen that the maximum negative lateral displacement of about -8X10 "4 mm occurs at the open, or "lower voltage,” position of the teeth 108 described above, and that the largest maximum positive lateral displacement of about +2.1X10 "4 , which is about a fourth of the maximum negative displacement, occurs at a displacement of about two-thirds of the full stroke length Y 0.120 mm.
  • the arcuate motion of the moving frame 102 can be greatly reduced in critical, or higher actuation-voltage regions of its stroke, at the expense of a larger arcuate motion in less critical, i.e., lower actuation-voltage areas in which it can be more easily tolerated.
  • the example moving frame 102 X-Y displacement curve of Fig.
  • a fabrication position may be any position between and/or including a deployment position (e.g., Fig. 2B) and a fully closed position (e.g., Fig. 2A).

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  • Engineering & Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Micromachines (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Lens Barrels (AREA)

Abstract

Selon un mode de réalisation, un actionneur comprend un cadre mobile accouplé à un cadre fixe par une pluralité de joints flexibles allongées à mouvement parallèle destinés à un mouvement globalement parallèle par rapport au cadre fixe et entre une position telle que fabriquée et une position déployée. Les joints flexibles sont disposés selon un premier angle par rapport à une ligne s'étendant perpendiculairement au cadre mobile et au cadre fixe lorsque le cadre mobile est disposé dans la position telle que fabriquée, et selon un second angle par rapport à cette même ligne lorsque le cadre mobile est disposé dans la position déployée. Le déplacement arqué du premier cadre par rapport au second cadre est commandé en limitant le premier angle à une valeur inférieure à environ la moitié de la somme des premier et second angles.
PCT/US2014/029529 2013-03-15 2014-03-14 Commande de mouvement arqué dans des actionneurs électrostatiques Ceased WO2014144925A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
KR1020157028922A KR102048335B1 (ko) 2013-03-15 2014-03-14 정전기 액추에이터에서 아치형 모션을 제어하는 방법 및 장치
JP2016503122A JP6397478B2 (ja) 2013-03-15 2014-03-14 静電アクチュエータにおける弧状運動の制御
CN201480026711.4A CN105209370B (zh) 2013-03-15 2014-03-14 静电致动器中的弧形运动控制

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US13/843,107 US8947797B2 (en) 2010-11-15 2013-03-15 Miniature MEMS actuator assemblies
US13/843,817 US8712229B2 (en) 2010-11-15 2013-03-15 Arcuate motion control in electrostatic actuators
US13/843,817 2013-03-15
US13/843,107 2013-03-15

Publications (1)

Publication Number Publication Date
WO2014144925A1 true WO2014144925A1 (fr) 2014-09-18

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PCT/US2014/029529 Ceased WO2014144925A1 (fr) 2013-03-15 2014-03-14 Commande de mouvement arqué dans des actionneurs électrostatiques

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Country Link
JP (1) JP6397478B2 (fr)
KR (1) KR102048335B1 (fr)
CN (1) CN105209370B (fr)
WO (1) WO2014144925A1 (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9549107B2 (en) * 2014-06-20 2017-01-17 Qualcomm Incorporated Autofocus for folded optic array cameras

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999037013A1 (fr) * 1998-01-13 1999-07-22 Seagate Technology, Inc. Microrupteur optique a micro-organe de commande electrostatique et son procede d'utilisation
US6384510B1 (en) * 1998-12-15 2002-05-07 Iolon, Inc. Electrostatic microactuator with offset and/or inclined comb drive fingers
US20120081598A1 (en) * 2010-11-15 2012-04-05 DigitalOptics Corporation MEMS Mems actuator device deployment

Family Cites Families (6)

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Publication number Priority date Publication date Assignee Title
US6411589B1 (en) * 1998-07-29 2002-06-25 Hewlett-Packard Company System and method for forming electrostatically actuated data storage mechanisms
WO2001096930A1 (fr) * 2000-06-09 2001-12-20 C Speed Corporation Systeme de miroir optique a commande rotative multi-axiale
JP4161950B2 (ja) * 2004-02-27 2008-10-08 セイコーエプソン株式会社 マイクロメカニカル静電アクチュエータ
JP4834443B2 (ja) * 2006-03-31 2011-12-14 株式会社東芝 圧電駆動型ｍｅｍｓアクチュエータ
CA2612206A1 (fr) * 2006-11-30 2008-05-30 Jds Uniphase Corporation Matrice a micromiroirs avec actionneur hybride
JP4219383B2 (ja) * 2006-12-28 2009-02-04 日本航空電子工業株式会社 櫛歯型静電アクチュエータ

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999037013A1 (fr) * 1998-01-13 1999-07-22 Seagate Technology, Inc. Microrupteur optique a micro-organe de commande electrostatique et son procede d'utilisation
US6384510B1 (en) * 1998-12-15 2002-05-07 Iolon, Inc. Electrostatic microactuator with offset and/or inclined comb drive fingers
US20120081598A1 (en) * 2010-11-15 2012-04-05 DigitalOptics Corporation MEMS Mems actuator device deployment

Also Published As

Publication number Publication date
KR20150140682A (ko) 2015-12-16
KR102048335B1 (ko) 2019-11-25
JP2016515793A (ja) 2016-05-30
JP6397478B2 (ja) 2018-09-26
CN105209370A (zh) 2015-12-30
CN105209370B (zh) 2018-01-19

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