WO2001095014A1 - Systeme de miroir optique a commande de rotation multiaxiale - Google Patents

Systeme de miroir optique a commande de rotation multiaxiale Download PDF

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Publication number
WO2001095014A1
WO2001095014A1 PCT/US2001/040885 US0140885W WO0195014A1 WO 2001095014 A1 WO2001095014 A1 WO 2001095014A1 US 0140885 W US0140885 W US 0140885W WO 0195014 A1 WO0195014 A1 WO 0195014A1
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WO
WIPO (PCT)
Prior art keywords
mirror
optical
actuators
mirror system
frame member
Prior art date
Application number
PCT/US2001/040885
Other languages
English (en)
Inventor
Paul Merritt Hagelin
Original Assignee
C Speed Corporation
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
Application filed by C Speed Corporation filed Critical C Speed Corporation
Priority to AU2001267050A priority Critical patent/AU2001267050A1/en
Publication of WO2001095014A1 publication Critical patent/WO2001095014A1/fr

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B26/00—Optical devices or arrangements for the control of light using movable or deformable optical elements
    • G02B26/08—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light
    • G02B26/0816—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light by means of one or more reflecting elements
    • G02B26/0833—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light by means of one or more reflecting elements the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD
    • G02B26/0841—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light by means of one or more reflecting elements the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD the reflecting element being moved or deformed by electrostatic means

Definitions

  • the present invention relates generally to a Microelectromechanical System (MEMS) fabricated optical mirror system that is capable of being tilted on two orthogonal axes, by means of electrostatic actuation. Particular application to the use of these mirrors in the deflection of optical space beams is emphasized.
  • MEMS Microelectromechanical System
  • Fiber optic communication systems currently employ switching systems to route signals at central office switching centers. These electro-optic systems rely on converting the light output from each "incoming" fiber into electrical form, extracting the data content in the resultant electrical signal, then utilizing conventional electrical switches to route the data content to a modulatable optical source that is coupled to a " destination" optical fiber. This detection, switching, and remodulation process is expensive, complex, power consuming, and subject to component failure.
  • fiber-to-fiber switches employing Grating Waveguides, Rowland Circle Gratings, and planar gratings, permit dedicated switching based on optical wavelength.
  • An optical mirror system design is desired that has high-resolution 2-D scanning capability and deflection capability, made with a surface-micromachining process. In order to achieve high-resolution, large mirror size and rotation angles are necessary.
  • the present invention addresses such a need.
  • An optical mirror system includes a mirror and a first frame member coupled to and surrounding the mirror via a first plurality of suspension beams.
  • the system also includes a first plurality of actuators coupled to the first frame member, and a second frame member coupled to and surrounding the first frame member via a second plurality of suspension beams.
  • the mirror rotates about a first axis relative to the first plurality of suspension beams.
  • the system includes a second plurality of actuators coupled to the second frame member.
  • a key feature of the present invention is the incorporation of a comb drive, an electrostatic actuator with interdigitated electrodes, to provide actuation to the mirror.
  • This comb drive facilitates low- voltage and high-force actuation.
  • the design also features self- assembly using bimorphs. The bimorph separates the two halves of the comb drive. Electrostatic force pulls the halves together.
  • the comb (preferably fabricated from a layer of polyciystalline silicon at least 4 ⁇ m thick) enables large forces (one or two orders of magnitude larger than conventional micromachined mirrors) while maintaining low actuation voltage and high resonant frequencies.
  • the actuator is built into the frame that supports the mirror. Putting the actuator in the frame also provides great flexibility in the mirror design. Furthermore, the actuator can be situated in the frame surrounding the mirror. This can reduce the overall size of the mirror.
  • optical add-drop multiplexers for example, optical add-drop multiplexers, wavelength routers, free-space optical interconnects, chip-level optical I/O, optical scanning displays, optical scanner (bar-codes, micro cameras), optical storage read/write heads, laser printers, medical replacement for glasses (incorporated with adaptive optics), medical diagnostic equipment, optical scanning for security applications. Integration of an optical scanning mirror with optical detectors can reduce the cost of imaging applications by reducing the number of detectors needed to capture 1-D or 2-D optical information.
  • a device in accordance with the present invention meets the requirements for a directly scalable, high port count optical switch, utilizing a unique two mirror per optical I/O port configuration.
  • Figure 1 is a conceptual drawing of an optical mirror system in accordance with the present invention.
  • Figure la is a top view showing bimorph in an optical mirror system in accordance with the present invention.
  • Figure lb is a side view of bimorph detail of an assembled optical mirror system in accordance with the present invention.
  • Figure lc is a side view of bimorph detail of an unassembled optical mirror system in accordance with the present invention.
  • Figure 2a is a first cross section of torsion detail of the inner frame of an unassembled optical mirror system in accordance with the present invention.
  • Figure 2b is a second cross section of torsion detail of the inner frame of an assembled optical mirror system in accordance with the present invention, having the electrodes assembled.
  • Figure 2c is a third cross section of torsion detail of the inner frame of an optical mirror system in accordance with the present invention, showing mirror tilt.
  • Figure 3 illustrates a top view of an actuator in accordance with the present invention.
  • Figure 4 illustrates a side view of the actuator of Figure 3.
  • Figure 5 illustrates an optical mirror system coupled to a substrate via anchors.
  • the present invention relates to an optical mirror and more particularly to an optical mirror system with a multi-axis rotational control.
  • the following description is presented to enable one of ordinary skill in the art to make and use the invention and is provided in the context of a patent application and its requirements.
  • Various modifications to the preferred embodiment and the generic principles and features described herein will be readily apparent to those skilled in the art.
  • the present invention is not intended to be limited to the embodiment shown but is to be accorded the widest scope consistent with the principles and features described herein.
  • the comb enables large forces while maintaining low actuation voltage and high resonant frequencies.
  • the actuator is built-in to the frame that supports the mirror. Putting the actuator in the frame provides great flexibility in the mirror design, which can reduce the overall size of the mirror system.
  • a system and method in accordance with the present invention utilizes a comb-drive in tilt-up optical mirror system.
  • the comb-drive can be self- assembled, and the mirror can be made of thin polysilicon and supported by a stiff frame. This lowers the mass of the mirror, enhancing its resonant frequency.
  • FIG. 1 is a conceptual drawing of an optical mirror system 100 in accordance with the present invention.
  • the optical mirror system 100 has an outer frame 104, with a first plurality of actuators 110 and 112, and an inner frame 102, with a second plurality of comb actuators 106 and 108.
  • the inner frame 102 surrounds the mirror 103, and the outer frame 104 surrounds the inner frame 102.
  • the inner frame 102 and outer frame 104 are coupled together by a plurality of suspension beams 122, 124, 126, and 128 (I added 126 and 128 to the figure).
  • the suspension beams are flexure beams. Both frames are coupled to the first and second plurality of actuators with bimorph flexures 134-140.
  • the optical mirror system is fabricated flat on the surface of the chip. Upon release, the bimorph separates the bottom edge of the actuator from the bottom edge of the frame. When voltage is applied between a frame and the actuator, the actuator is pulled back to the frame. The actuation is stable and can achieve analog positioning control.
  • Figure la is a top view showing a bimorph in an optical mirror system in accordance with the present invention.
  • the frame 102 is coupled to one alf of the comb drive 208 and the bimorph 134.
  • the other half of the comb drive 106 (corrected call-out) is coupled through a plurality of flexure beams 114, 116 to the mirror 103.
  • a first plurality of flexure beams 210 are coupled to the bimorph 134 and the actuator half 106.
  • Figure lb is a side view of detail of an assembled bimorph 134 in accordance with the present invention.
  • Figure lc is a side view of detail of an unassembled bimorph 134 in accordance with the present invention.
  • the first plurality of actuators 106 and 108 connect to the mirror 103 through torsion flexure beams 114, 116, 118 and 120. Short, thin torsion beams are desired to minimize sagging that can reduce the angular range of the mirror.
  • actuator 106 When actuator 106 is activated, the position of actuator 108 does not change appreciably because the bimorph flexures are stiff in relation to torsion flexures 116- 120.
  • the differential height between actuators 106 and 108 cause the mirror to rotate.
  • the actuators 110 and 112 in the outer frame 104 connect to the inner frame 102 in the same manner. Bi-directional actuation on orthogonal axes is possible with this method.
  • Electrodes are routed to frame 102 with use conductors and insulators. If the torsion beams are electrically conductive, they can be used to route the driving signals between the frames 102 and 104. A total of five electrical connections are made to actuators 106, 108, 110 and 112 and to frame 102 and 104 to perform the bidirectional actuation. The frame can be connected to electrical ground. If bi-directional actuation is not necessary, two actuators can be used to perform unidirectional actuation on two rotational axes, requiring a total of three electrical connections.
  • Figure 2a (corrected call-outs) is a cross-section of detail of the flexure beam of an unassembled optical mirror system in accordance with the present invention.
  • Figure 2b is a cross-section of torsion detail of the flexure beam of an assembled optical mirror system in accordance with the present invention.
  • Figure 2c is a cross-section of torsion detail showing mirror rotation in response to activation of an actuator.
  • the comb drive enables large forces while maintaining low actuation voltage and high resonant frequencies.
  • the actuator is built-in to the frame that supports the mirror.
  • Figure 3 illustrates a top view of an actuator in accordance with the present invention.
  • Figure 4 illustrates a side view of the actuator of Figure 3.
  • the end portions 302 and 304 engage the middle portion 306 through interdigitated teeth 308 and 310.
  • each of the end portions 302 and 304 comprise three electrically isolated actuators 302a-302c and 304a-304c, respectively.
  • the middle portion 306 pulls "up". If actuators 302b and 304b are activated, the middle portion 306 holds the position shown, and if actuators 302c and 304c are activated, the middle portion 306 pulls down. Accordingly, the actuator system 105 can move the mirror in various ways dependent upon the voltages applied to the motors 302a-302c and 304a-304c.
  • actuator system 105 has been described in the context of a three position (up, down and hold position) system, one of ordinary skill in the art readily recognizes that a two position (up or down), (hold position or down), (hold position or up) could be provided by using two actuators rather than the three actuators in the system disclosed herein.
  • the system 105 could be operated in a rotational mode by activating electrodes on a diagonal, such as 304a and 302c.
  • this system could utilize a parallel plate drive actuator and its use would be within the spirit and scope of the present invention.
  • the frame 104 can be attached to actuator 501 that is connected to the substrate through flexures 503 and anchors 504.
  • the substrate can have actuators thereon used to elevate the mirror above the substrate, or to rotate the mirror.
  • the electrostatic actuators can be uni-directional or bi-directional and the actuators could be parallel plate or comb drive. Further, the actuators are not limited to electrostatic technology.
  • the electrodes in the electrostatic actuators can be separated by a bimorph, by a sacrifical layer or by any combination thereof.
  • the outer frame of the mirror is separated from the substrate by a self-assembly mechanism that provides clearance for mirror rotation.
  • This self- assembly mechanism can be powered by bimorphs or other forms of actuation, such as electrostatic.
  • Putting the actuator in the frame also provides great flexibility in the mirror design.
  • the actuator can be situated in the frame surrounding the mirror. This can reduce the overall size of the mirror.
  • a mirror in accordance with the present invention can be operated in a bi-directional mode, and electrodes on each axis can be used to perform bi-directional motion.
  • one electrode is dedicated to each direction of rotation on each axis which can add to the overall cost.
  • the number of mechanical connections to the mirror enables more independent electrical interconnects, which can be used for other features, such as active shaping of the mirror surface.
  • Another advantage of an optical mirror in accordance with the present invention is that, due to the distances between the actuators (on opposite sides of the mirror), there effectively is no electrical cross-talk.
  • the present invention has been described in accordance with the embodiments shown, one of ordinary skill in the art will readily recognize that there could be variations to the embodiments and those variations would be within the spirit and scope of the present invention.
  • the mirror can rotate in a plurality of directions (i.e. twisting motion) dependent upon the electrostatic forces applied thereto. Accordingly, many modifications may be made by one of ordinary skill in the art without departing from the spirit and scope of the appended claims.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Mechanical Light Control Or Optical Switches (AREA)

Abstract

L'invention concerne un système de miroir optique (103) comprenant des cadres extérieur et intérieur (104 et 102), le cadre intérieur étant relié au miroir et le cadre extérieur étant relié au cadre intérieur par des poutres de suspension et des éléments de flexion.
PCT/US2001/040885 2000-06-09 2001-06-07 Systeme de miroir optique a commande de rotation multiaxiale WO2001095014A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU2001267050A AU2001267050A1 (en) 2000-06-09 2001-06-07 Optical mirror system with multi-axis rotational control

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US59088800A 2000-06-09 2000-06-09
US09/590,888 2000-06-09

Publications (1)

Publication Number Publication Date
WO2001095014A1 true WO2001095014A1 (fr) 2001-12-13

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PCT/US2001/040885 WO2001095014A1 (fr) 2000-06-09 2001-06-07 Systeme de miroir optique a commande de rotation multiaxiale

Country Status (2)

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AU (1) AU2001267050A1 (fr)
WO (1) WO2001095014A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006022967A1 (fr) * 2004-08-02 2006-03-02 Advanced Nano Systems, Inc. Miroir mems a angle de rotation amplifie
WO2009127273A2 (fr) * 2008-04-18 2009-10-22 Robert Bosch Gmbh Procédé de fabrication d'un composant micromécanique et composant micromécanique
WO2019042982A1 (fr) * 2017-08-31 2019-03-07 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Plateforme de translation et d'inclinaison multidirectionnelle utilisant des actionneurs à flexion comme entité active

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5579148A (en) * 1993-11-29 1996-11-26 Nippondenso Co., Ltd. Two-dimensional optical scanner
US5969465A (en) * 1997-04-01 1999-10-19 Xros, Inc. Adjusting operating characteristics of micromachined torsional oscillators

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5579148A (en) * 1993-11-29 1996-11-26 Nippondenso Co., Ltd. Two-dimensional optical scanner
US5969465A (en) * 1997-04-01 1999-10-19 Xros, Inc. Adjusting operating characteristics of micromachined torsional oscillators

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006022967A1 (fr) * 2004-08-02 2006-03-02 Advanced Nano Systems, Inc. Miroir mems a angle de rotation amplifie
WO2009127273A2 (fr) * 2008-04-18 2009-10-22 Robert Bosch Gmbh Procédé de fabrication d'un composant micromécanique et composant micromécanique
WO2009127273A3 (fr) * 2008-04-18 2010-05-06 Robert Bosch Gmbh Procédé de fabrication d'un composant micromécanique et composant micromécanique
WO2019042982A1 (fr) * 2017-08-31 2019-03-07 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Plateforme de translation et d'inclinaison multidirectionnelle utilisant des actionneurs à flexion comme entité active
US11697584B2 (en) 2017-08-31 2023-07-11 Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.V. Multidirectional translating and tilting platform using bending actuators as active entity

Also Published As

Publication number Publication date
AU2001267050A1 (en) 2001-12-17

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