US20070064292A1 - Magnet on frame oscillating device - Google Patents
Magnet on frame oscillating device Download PDFInfo
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- US20070064292A1 US20070064292A1 US11/228,894 US22889405A US2007064292A1 US 20070064292 A1 US20070064292 A1 US 20070064292A1 US 22889405 A US22889405 A US 22889405A US 2007064292 A1 US2007064292 A1 US 2007064292A1
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- oscillating
- torsional
- hinged device
- central portion
- hinges
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- 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
- G02B26/085—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 means being moved or deformed by electromagnetic means
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- 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
- G02B26/0858—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 means being moved or deformed by piezoelectric means
Definitions
- the present invention relates generally to the field of torsional hinged MEMS (Micro Electro Mechanical Systems) oscillating devices. More particularly, the invention relates to methods and apparatus for providing a pivoting device such as a mirror, which includes a permanent magnet as a part of either the magnetic drive mechanism, a magnetic sensing mechanism, or both, and wherein the magnet(s) is not mounted on the back side of the mirror.
- a pivoting device such as a mirror, which includes a permanent magnet as a part of either the magnetic drive mechanism, a magnetic sensing mechanism, or both, and wherein the magnet(s) is not mounted on the back side of the mirror.
- a permanent magnet is mounted to the back side of the resonating device, such as the back side of a mirror surface.
- This permanent magnet interacts with a drive coil located very close to the device.
- the critical mass balance of the device requires that the permanent magnet be designed with a size, thickness, and mass having very close tolerances.
- Other resonant torsional hinged device arrangements may use the permanent magnet as a sensing magnet and use an inertia or piezoelectric drive mechanism to maintain the device or mirror oscillating at its resonant frequency.
- embodiments of the present invention which provides a torsional hinged pivoting device such as a mirror with a magnetic drive mechanism.
- the torsional hinged device comprises a pair of torsional hinges where each hinge of the pair of hinges extends along a pivot axis from a first end to a second end.
- An oscillating surface such as a mirror, is located between and connected to the first end of each one of the pair of torsional hinges.
- First and second anchor members include a support structure portion mounted to a support structure, a central portion lying along the pivot axis and connecting regions having a reduced cross-sectional area connecting the support portion to the central portion. The central portion of each anchor member is connected to the second end of a torsional hinge.
- An enlarged mounting area lies along the pivot axis and is connected to the central portion of the anchor members opposite the connection to the torsional hinge.
- the connecting regions having the reduced cross-sectional areas may have a thickness that is less than the thickness of the central portion.
- the reduced cross-sectional areas may be formed by etching trenches completely through the material and extending between the enlarged mounting area and the support portions of the anchor member.
- the reduced cross-sectional area results in the mounting area being rigidly connected to the torsional hinges and flexibility connected to the anchor support portions on either side of the hinge axis.
- a permanent magnet or a ferromagnetic high permeability material may be attached to the mounting area(s).
- both magnets can be used as drive magnets, or one magnet can be a drive magnet and the other could be used as a position sensing magnet.
- the structure may include a sensing magnet attached to the mounting area and a piezoelectric drive elements attached to the support portions of the anchors.
- a coil comprising a multiplicity of electrical windings mounted proximate each of the mounting areas where a magnet is mounted. If the magnet is to provide a driving force to oscillate the device, an alternating electric current provided from a power source flows through the multiplicity of winding and creates a magnetic force that interacts with the permanent magnet to pivot the mirror member about the torsional hinge. If the magnet is to operate as a sensing magnet, the magnetic flux created by the permanent magnet on the oscillating structure will move past the electrical coil and will induce a voltage in the coil that is representative of the angular motion or position of the oscillating device or mirror. The voltage induced in the coil can be monitored to track the angular movement of the mirror.
- FIG. 1 is a perspective view of a first embodiment of the present invention illustrating a permanent magnet mounted on the mounting area at both anchor members;
- FIG. 1A is a partial perspective view of another embodiment illustrating a piezoelectric element mounted on one of the support anchors;
- FIG. 2 is another embodiment of the present invention similar to FIG. 1 , but shows a multilayer oscillating structure
- FIG. 3 is yet another embodiment of the invention similar to FIG. 2 but illustrates a different method of attaching an enlarged mounting area to the support anchors;
- FIG. 4 is a perspective view of a prior art torsional hinged device, wherein a magnet is mounted to the back side of the device;
- FIG. 5 is a perspective view of a torsional hinged device, wherein a magnet is mounted to the mounting areas on the hinge.
- the mirror device 12 includes an anchor such as frame 14 and an operating portion or 16 .
- Operating portion 16 may be any selected device, including but not limited to mirrors, optical gratings, etc.
- the operating portion 16 illustrated in FIG. 4 is a mirror having reflective surface 18 for reflecting light, and is supported by a pair of torsional hinges 20 and 22 that extend from the operating portion or device 16 to the anchor or frame 14 .
- the anchor is illustrated as a frame 14 , however, it will be appreciated that instead of a complete frame around the device 16 , the anchor 14 may simply include a pair of anchor pads 14 a and 14 b as indicated by dotted lines.
- a drive mechanism applies torque to the operating surface of the device or mirror so that the device 16 such as mirror surface 18 will pivot or oscillate (preferably at a resonant frequency) about the torsional hinges 20 and 22 .
- the pivot axis or selected axis 24 lies along the torsional hinges 20 and 22 .
- the drive mechanism is illustrated as a permanent magnet 26 bonded to the back side of the operating portion or device 16 . Permanent magnet 26 interacts with magnetic forces created by coils or windings located proximate the permanent magnet.
- frame 14 or the anchor pads 14 a and 14 b are mounted to a support structure (not shown).
- FIG. 5 there is shown an example of a presently available single layer torsional hinged device 16 that includes enlarged mounting areas on each of the torsional hinges.
- Those components and elements of the device illustrated in FIG. 5 that are common to the structure of FIG. 4 will carry the same reference numbers as in the previously discussed prior art FIG. 4 .
- an elongated ellipse shaped portion 16 such as a mirror, supported by a first torsional hinged 20 having a first portion 20 a and a second portion 20 b separated by an enlarged mounting area 28 .
- one end of the torsional hinged portion 20 a is attached to anchor member 14 a and the other end is attached to the enlarged mounting area 28 .
- One end of torsional hinged portion 20 b is attached to the enlarged mounting area 28 and the other end is attached to the operating portion or mirror 16 .
- the structure of FIG. 5 includes a permanent magnet 30 attached to mounting area 28 that interacts with a winding or coil 32 .
- a second torsional hinge 22 also includes first and second hinge portions 22 a and 22 b, another enlarged mounting area 34 , and another permanent magnet 36 .
- each of the magnets 30 and 36 are comprised of first magnet portions 30 a and 36 a on one surface of enlarged areas 28 and 34 and second magnet portions 30 b and 36 b on the opposite surface of enlarged areas 28 and 34 respectively.
- first magnet portions 30 a and 36 a on one surface of enlarged areas 28 and 34
- second magnet portions 30 b and 36 b on the opposite surface of enlarged areas 28 and 34 respectively.
- one of the top or bottom portions of the magnets 30 and 36 mounted on enlarged areas 28 and 34 can be eliminated and only one portion of the magnets 30 a and 36 a used.
- both the combination of permanent magnet 30 and coil 32 and the combination of permanent magnet 36 and coil 38 may be used to drive the oscillations of operating surface or mirror 16 . More specifically, if a drive signal having a frequency substantially the same as the resonant frequency of the device 16 is applied across the coils 32 and/or 38 , device 16 should pivot back and forth around pivot axis 24 at its resonant frequency, as a result of the interaction of the torque applied by the coils 32 and 38 to the permanent magnets 30 and 36 .
- the drive signal can be applied across only one of the two coils or windings to cause the mirror to pivot at resonance. If only one coil and permanent magnet combination is used to drive and maintain the mirror oscillating at its resonant frequency, the other coil and permanent magnet combination may be used to monitor the angular position or movement of the oscillating mirror.
- the changing magnetic flux of the moving or oscillating permanent magnets (either 30 or 36 ) intersecting an adjacent coil 32 and 38 will induce an alternating voltage representative of the angular position of the oscillating device 16 . By monitoring this changing voltage, the angular position of the oscillating mirror is known or can be determined.
- the device of the structure of FIG. 5 also illustrates that the drive magnets may be moved from the back side of the operating surface or mirror (as shown in FIG. 4 ) to the hinge area.
- This change significantly reduces the rotational inertia and the hinge stress and allows a greater radius or curvature on the pivoting device 16 since the magnet does not go through the full angular motion that is traveled by the operating device 16 , such as for example the mirror surface 18 . Therefore, the resulting device is stronger and more robust.
- This approach solves many of the problems associated with the mirror structure of FIG. 4 .
- the distance between anchors 14 a and 14 b is longer than equivalent device or mirror of the type shown in FIG. 4 . This increase in size, and the corresponding increase in packaging size adds cost, which distracts from the other advantages of the structure.
- FIG. 1 there is illustrated a first embodiment of the present invention that can pivot or oscillate at its resonant frequency and that includes the advantages of the structure of FIG. 5 , but is not substantially larger than the structure of FIG. 4 .
- Those elements of the device of FIG. 1 that are the same as, and operate the same as the elements of the structures of FIGS. 4 and 5 carry the same reference numbers.
- the structure of FIG. 1 includes several of the elements of FIGS. 4 and 5 including a frame and/or anchor members 40 a and 40 b, the operating surface or mirror 16 , and torsional hinges 20 and 22 .
- the torsional hinges 20 and 22 do not include the enlarged mounting areas 28 and 34 , but instead extend directly between the operating device 16 and the anchors 40 a and 40 b.
- enlarged mounting areas 42 and 44 are attached to anchors 40 a and 40 b opposite hinges 20 and 22 .
- anchors 40 a and 40 b include a central portion that is attached to the torsional hinges.
- FIG. 1 The reduced area of FIG. 1 is defined by trenches 46 a and 46 b that separate the enlarged areas 42 and 44 from the anchor members. As is also illustrated in FIG. 1 , trenches 46 a and 46 b are etched completely through the material of anchors 40 a and 40 b.
- Permanent magnets 30 and 36 are mounted to the enlarged areas 42 and 44 in a manner similar to the structure of FIG. 2 . Also as discussed above, permanent magnets 30 and 36 interact with coils 32 and 38 to provide torque to the mirror and/or to monitor the angular position of the operating device 16 .
- the permanent magnets could be replaced with a ferromagnetic material such as a nickel/iron alloy since such materials are attracted to a magnetic field.
- the ferromagnetic material could be used to either drive the oscillating mirror or to sense the angular position.
- to use the ferromagnetic material to sense angular position will require sending changes in the inductance, rather than a voltage.
- FIG. 1A is a partial perspective view of another embodiment of the invention wherein piezoelectric elements 48 a and 48 b, with electrical connections 50 a, 50 b, 50 c, and 50 d are attached to at least one of the anchor pads (e.g. anchor pad 14 b ) for providing oscillations to the device 16 .
- the anchor pads e.g. anchor pad 14 b
- a piezoelectric element is used as the drive source at only one anchor pad and torsional hinge (e.g. 14 b and 18 )
- a magnet arrangement such as shown in FIGS. 1-3 may be used with the anchor pad 14 a and the torsional hinge 20 at the other side (e.g. 20 ), to monitor the angular position of the device.
- the device may be driven according to the teaching of this invention with a magnet arrangement as discussed above, and the piezoelectric element arrangement of FIG. 1A may be used to monitor the angular position of the device.
- FIG. 2 is similar to FIG. 1 and those elements of FIG. 2 that are common to FIG. 1 carry the same reference number.
- FIG. 2 illustrates that the oscillating mirror portion of the structure may be multilayered.
- a hinge layer that includes the torsional hinges 20 and 22 , and a truss portion 16 a.
- a reflective surface layer 16 b is attached to one side of the truss structure 16 a and a balancing layer 16 c is attached to the other surface of truss structure 16 a.
- Balancing layer 16 c is designed to balance the mass of reflective portion surface layer 16 b so that the center of mass lies along the axis 24 .
- all three layers 16 a, 16 b, and 16 c could be separate structures bonded together, or preferably the reflective surface portion 16 b and the truss structure 16 a could be etched from a single piece of silicon.
- FIG. 3 shows a multilayer structure similar to that of FIG. 2 , but attaches the enlarged mounting areas 42 and 44 to the outside edge of the central portion of the support anchors 52 a and 52 b and opposite the torsional hinges 20 and 27 respectively.
- the reduced areas connecting to support portions to the central portion are thinned areas 54 a, 54 b, 54 c, and 54 d. Thinned areas 54 a, 54 b, 54 c, and 54 d are used rather than the trenches 46 a and 46 b, discussed with respect to FIGS. 1 and 2 .
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- Physics & Mathematics (AREA)
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- Optics & Photonics (AREA)
- Electromagnetism (AREA)
- Mechanical Optical Scanning Systems (AREA)
- Mechanical Light Control Or Optical Switches (AREA)
Abstract
Description
- This application relates to the following co-pending and commonly assigned patent applications: (TI-60301) Ser. No. ______, filed herewith, entitled Resonant Oscillating Device Actuator Structure and (TI-60302) Ser. No. ______, filed herewith, entitled Apparatus And Method For Adjusting The Resonant Frequency Of An Oscillating Device, which applications are hereby incorporated herein by reference.
- The present invention relates generally to the field of torsional hinged MEMS (Micro Electro Mechanical Systems) oscillating devices. More particularly, the invention relates to methods and apparatus for providing a pivoting device such as a mirror, which includes a permanent magnet as a part of either the magnetic drive mechanism, a magnetic sensing mechanism, or both, and wherein the magnet(s) is not mounted on the back side of the mirror.
- The use of rotating polygon scanning mirrors in laser printers to provide a beam sweep or scan of the image of a modulated light source across a photoresisted medium, such as a rotating drum, is well known. More recently, there have been efforts to use a much less expensive flat member with a single reflective surface, such as a resonant oscillating mirror to provide the scanning beam. Further, resonant oscillating members other than mirrors may also be useful. These resonant scanning devices provide excellent performance at a very advantageous cost. However, because a permanent magnet (drive or sensing) is typically mounted on the back side of the resonant member, the center of mass of the magnet and other rotating elements have very close and critical tolerances.
- In addition, the critical mass of the device further complicates the task of maintaining the resonant frequency within acceptable tolerances. According to prior art magnetic drive mechanisms for these oscillating devices, a permanent magnet is mounted to the back side of the resonating device, such as the back side of a mirror surface. This permanent magnet interacts with a drive coil located very close to the device. The critical mass balance of the device requires that the permanent magnet be designed with a size, thickness, and mass having very close tolerances. Other resonant torsional hinged device arrangements may use the permanent magnet as a sensing magnet and use an inertia or piezoelectric drive mechanism to maintain the device or mirror oscillating at its resonant frequency.
- However, regardless of whether the magnet is used as a sensing magnet or a drive magnet, it causes problems in maintaining the flatness of the device and significantly increases the oscillating mass. Since a primary use of torsional hinged devices is the scanning mirror in laser printers, flatness and a stable resonant frequency is important. One solution to the problems discussed above is to move the permanent magnet from the back of the oscillating device or mirror onto the torsional hinges. Unfortunately, although this solution solves many of the problems discussed above, it also adds length to the device, which of course makes the device larger and more costly.
- Therefore, it would be advantageous to provide an inexpensive and easily manufactured mirror structure that has the advantages of a system wherein the magnets are mounted on the torsional hinges but does not require the extra length of such a structure.
- These and other problems are generally solved or circumvented, and technical advantages are generally achieved, by embodiments of the present invention, which provides a torsional hinged pivoting device such as a mirror with a magnetic drive mechanism.
- The torsional hinged device comprises a pair of torsional hinges where each hinge of the pair of hinges extends along a pivot axis from a first end to a second end. An oscillating surface, such as a mirror, is located between and connected to the first end of each one of the pair of torsional hinges. First and second anchor members include a support structure portion mounted to a support structure, a central portion lying along the pivot axis and connecting regions having a reduced cross-sectional area connecting the support portion to the central portion. The central portion of each anchor member is connected to the second end of a torsional hinge.
- An enlarged mounting area lies along the pivot axis and is connected to the central portion of the anchor members opposite the connection to the torsional hinge. The connecting regions having the reduced cross-sectional areas may have a thickness that is less than the thickness of the central portion. Alternately, the reduced cross-sectional areas may be formed by etching trenches completely through the material and extending between the enlarged mounting area and the support portions of the anchor member. The reduced cross-sectional area results in the mounting area being rigidly connected to the torsional hinges and flexibility connected to the anchor support portions on either side of the hinge axis. A permanent magnet or a ferromagnetic high permeability material may be attached to the mounting area(s). If the device includes mounting areas and magnets proximate both anchors, both magnets can be used as drive magnets, or one magnet can be a drive magnet and the other could be used as a position sensing magnet. Alternately, the structure may include a sensing magnet attached to the mounting area and a piezoelectric drive elements attached to the support portions of the anchors.
- There is also provided a coil comprising a multiplicity of electrical windings mounted proximate each of the mounting areas where a magnet is mounted. If the magnet is to provide a driving force to oscillate the device, an alternating electric current provided from a power source flows through the multiplicity of winding and creates a magnetic force that interacts with the permanent magnet to pivot the mirror member about the torsional hinge. If the magnet is to operate as a sensing magnet, the magnetic flux created by the permanent magnet on the oscillating structure will move past the electrical coil and will induce a voltage in the coil that is representative of the angular motion or position of the oscillating device or mirror. The voltage induced in the coil can be monitored to track the angular movement of the mirror.
- The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter, which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures or processes for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims.
- For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawing, in which:
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FIG. 1 is a perspective view of a first embodiment of the present invention illustrating a permanent magnet mounted on the mounting area at both anchor members; -
FIG. 1A is a partial perspective view of another embodiment illustrating a piezoelectric element mounted on one of the support anchors; -
FIG. 2 is another embodiment of the present invention similar toFIG. 1 , but shows a multilayer oscillating structure; -
FIG. 3 is yet another embodiment of the invention similar toFIG. 2 but illustrates a different method of attaching an enlarged mounting area to the support anchors; -
FIG. 4 is a perspective view of a prior art torsional hinged device, wherein a magnet is mounted to the back side of the device; and -
FIG. 5 is a perspective view of a torsional hinged device, wherein a magnet is mounted to the mounting areas on the hinge. - The making and using of the presently preferred embodiments are discussed in detail below. It should be appreciated, however, that the present invention provides many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific embodiments discussed are merely illustrative of specific ways to make and use the invention, and do not limit the scope of the invention.
- Referring now to
FIG. 4 , there is shown a prior art device or mirror 12 using torsional hinges. As shown inFIG. 4 , the mirror device 12 includes an anchor such asframe 14 and an operating portion or 16.Operating portion 16 may be any selected device, including but not limited to mirrors, optical gratings, etc. Theoperating portion 16 illustrated inFIG. 4 is a mirror havingreflective surface 18 for reflecting light, and is supported by a pair oftorsional hinges device 16 to the anchor orframe 14. In the embodiment ofFIG. 4 , the anchor is illustrated as aframe 14, however, it will be appreciated that instead of a complete frame around thedevice 16, theanchor 14 may simply include a pair of anchor pads 14 a and 14 b as indicated by dotted lines. - A drive mechanism applies torque to the operating surface of the device or mirror so that the
device 16 such asmirror surface 18 will pivot or oscillate (preferably at a resonant frequency) about thetorsional hinges selected axis 24 lies along thetorsional hinges permanent magnet 26 bonded to the back side of the operating portion ordevice 16.Permanent magnet 26 interacts with magnetic forces created by coils or windings located proximate the permanent magnet. - In the embodiment shown in
FIG. 4 ,frame 14 or the anchor pads 14 a and 14 b are mounted to a support structure (not shown). - Referring now to
FIG. 5 , there is shown an example of a presently available single layer torsional hingeddevice 16 that includes enlarged mounting areas on each of the torsional hinges. Those components and elements of the device illustrated inFIG. 5 that are common to the structure ofFIG. 4 will carry the same reference numbers as in the previously discussed prior artFIG. 4 . As shown inFIG. 5 , there is an elongated ellipse shapedportion 16, such as a mirror, supported by a first torsional hinged 20 having afirst portion 20 a and a second portion 20 b separated by an enlarged mounting area 28. As shown, one end of the torsional hingedportion 20 a is attached to anchor member 14 a and the other end is attached to the enlarged mounting area 28. One end of torsional hinged portion 20 b is attached to the enlarged mounting area 28 and the other end is attached to the operating portion ormirror 16. In addition, the structure ofFIG. 5 includes apermanent magnet 30 attached to mounting area 28 that interacts with a winding or coil 32. In a similar manner, a secondtorsional hinge 22 also includes first and second hinge portions 22 a and 22 b, another enlarged mountingarea 34, and anotherpermanent magnet 36. There is also included acoil 38 located proximate thepermanent magnet 36. - It should also be noted that in the illustration of
FIG. 5 , each of themagnets first magnet portions 30 a and 36 a on one surface ofenlarged areas 28 and 34 and second magnet portions 30 b and 36 b on the opposite surface ofenlarged areas 28 and 34 respectively. However, it will be appreciated by those skilled in the art that one of the top or bottom portions of themagnets enlarged areas 28 and 34 can be eliminated and only one portion of themagnets 30 a and 36 a used. - In the embodiment in
FIG. 5 , both the combination ofpermanent magnet 30 and coil 32 and the combination ofpermanent magnet 36 andcoil 38 may be used to drive the oscillations of operating surface ormirror 16. More specifically, if a drive signal having a frequency substantially the same as the resonant frequency of thedevice 16 is applied across the coils 32 and/or 38,device 16 should pivot back and forth aroundpivot axis 24 at its resonant frequency, as a result of the interaction of the torque applied by thecoils 32 and 38 to thepermanent magnets - Alternately, the drive signal can be applied across only one of the two coils or windings to cause the mirror to pivot at resonance. If only one coil and permanent magnet combination is used to drive and maintain the mirror oscillating at its resonant frequency, the other coil and permanent magnet combination may be used to monitor the angular position or movement of the oscillating mirror. As will be appreciated by those skilled in the art, the changing magnetic flux of the moving or oscillating permanent magnets (either 30 or 36) intersecting an
adjacent coil 32 and 38 will induce an alternating voltage representative of the angular position of theoscillating device 16. By monitoring this changing voltage, the angular position of the oscillating mirror is known or can be determined. - The device of the structure of
FIG. 5 also illustrates that the drive magnets may be moved from the back side of the operating surface or mirror (as shown inFIG. 4 ) to the hinge area. This change significantly reduces the rotational inertia and the hinge stress and allows a greater radius or curvature on thepivoting device 16 since the magnet does not go through the full angular motion that is traveled by the operatingdevice 16, such as for example themirror surface 18. Therefore, the resulting device is stronger and more robust. This approach solves many of the problems associated with the mirror structure ofFIG. 4 . Unfortunately, as can be seen, the distance between anchors 14 a and 14 b is longer than equivalent device or mirror of the type shown inFIG. 4 . This increase in size, and the corresponding increase in packaging size adds cost, which distracts from the other advantages of the structure. - Therefore, referring now to
FIG. 1 , there is illustrated a first embodiment of the present invention that can pivot or oscillate at its resonant frequency and that includes the advantages of the structure ofFIG. 5 , but is not substantially larger than the structure ofFIG. 4 . Those elements of the device ofFIG. 1 that are the same as, and operate the same as the elements of the structures ofFIGS. 4 and 5 carry the same reference numbers. - As shown, the structure of
FIG. 1 includes several of the elements ofFIGS. 4 and 5 including a frame and/oranchor members mirror 16, and torsional hinges 20 and 22. However, the torsional hinges 20 and 22 do not include the enlarged mountingareas 28 and 34, but instead extend directly between the operatingdevice 16 and theanchors areas anchors FIG. 1 , anchors 40 a and 40 b include a central portion that is attached to the torsional hinges. Support portions on each side of the hinges are connected together by a region having a reduced cross-sectional area. The reduced area ofFIG. 1 is defined bytrenches 46 a and 46 b that separate theenlarged areas FIG. 1 ,trenches 46 a and 46 b are etched completely through the material ofanchors Permanent magnets enlarged areas FIG. 2 . Also as discussed above,permanent magnets coils 32 and 38 to provide torque to the mirror and/or to monitor the angular position of the operatingdevice 16. It should also be appreciated that the permanent magnets could be replaced with a ferromagnetic material such as a nickel/iron alloy since such materials are attracted to a magnetic field. The ferromagnetic material could be used to either drive the oscillating mirror or to sense the angular position. However, to use the ferromagnetic material to sense angular position will require sending changes in the inductance, rather than a voltage. -
FIG. 1A is a partial perspective view of another embodiment of the invention wherein piezoelectric elements 48 a and 48 b, withelectrical connections 50 a, 50 b, 50 c, and 50 d are attached to at least one of the anchor pads (e.g. anchor pad 14 b) for providing oscillations to thedevice 16. - If a piezoelectric element is used as the drive source at only one anchor pad and torsional hinge (e.g. 14 b and 18), a magnet arrangement such as shown in
FIGS. 1-3 may be used with the anchor pad 14 a and thetorsional hinge 20 at the other side (e.g. 20), to monitor the angular position of the device. Alternately, the device may be driven according to the teaching of this invention with a magnet arrangement as discussed above, and the piezoelectric element arrangement ofFIG. 1A may be used to monitor the angular position of the device. -
FIG. 2 is similar toFIG. 1 and those elements ofFIG. 2 that are common toFIG. 1 carry the same reference number. However, instead of a single layer mirror structure,FIG. 2 illustrates that the oscillating mirror portion of the structure may be multilayered. As shown, there is a hinge layer that includes the torsional hinges 20 and 22, and a truss portion 16 a. A reflective surface layer 16 b is attached to one side of the truss structure 16 a and a balancing layer 16 c is attached to the other surface of truss structure 16 a. Balancing layer 16 c is designed to balance the mass of reflective portion surface layer 16 b so that the center of mass lies along theaxis 24. It will also be appreciated by those skilled in the art that all three layers 16 a, 16 b, and 16 c could be separate structures bonded together, or preferably the reflective surface portion 16 b and the truss structure 16 a could be etched from a single piece of silicon. -
FIG. 3 shows a multilayer structure similar to that ofFIG. 2 , but attaches the enlarged mountingareas areas 54 a, 54 b, 54 c, and 54 d. Thinnedareas 54 a, 54 b, 54 c, and 54 d are used rather than thetrenches 46 a and 46 b, discussed with respect toFIGS. 1 and 2 . - Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.
- Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, machines, methods, or steps, presently existing or later to be developed, that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such machines, means, methods, or steps.
Claims (19)
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
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US11/228,894 US7187483B1 (en) | 2005-09-16 | 2005-09-16 | Magnet on frame oscillating device |
EP06803751.4A EP1949168B1 (en) | 2005-09-16 | 2006-09-18 | Magnet on frame oscillating device |
CNA2006800425522A CN101310207A (en) | 2005-09-16 | 2006-09-18 | Magnet on frame oscillating device |
PCT/US2006/036218 WO2007035594A1 (en) | 2005-09-16 | 2006-09-18 | Magnet on frame oscillating device |
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US11/228,894 US7187483B1 (en) | 2005-09-16 | 2005-09-16 | Magnet on frame oscillating device |
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US7187483B1 US7187483B1 (en) | 2007-03-06 |
US20070064292A1 true US20070064292A1 (en) | 2007-03-22 |
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US11/228,894 Active US7187483B1 (en) | 2005-09-16 | 2005-09-16 | Magnet on frame oscillating device |
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US (1) | US7187483B1 (en) |
EP (1) | EP1949168B1 (en) |
CN (1) | CN101310207A (en) |
WO (1) | WO2007035594A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
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US20100002284A1 (en) * | 2008-07-02 | 2010-01-07 | Long-Sun Huang | Method of modulating resonant frequency of torsional mems device |
US20140118809A1 (en) * | 2011-07-06 | 2014-05-01 | Nec Corporation | Optical scanning device, image display apparatus and optical scanning method |
CN109683308A (en) * | 2019-02-01 | 2019-04-26 | 西安知微传感技术有限公司 | A kind of electromagnetic drive galvanometer reducing oscillating motion |
Families Citing this family (6)
Publication number | Priority date | Publication date | Assignee | Title |
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JP4329831B2 (en) * | 2007-03-12 | 2009-09-09 | セイコーエプソン株式会社 | Actuator, optical scanner and image forming apparatus |
JP2017181715A (en) * | 2016-03-30 | 2017-10-05 | セイコーエプソン株式会社 | Optical scanner component, optical scanner, manufacturing method of the same, image display unit, and head mount display |
US10895713B2 (en) * | 2018-10-18 | 2021-01-19 | Microsoft Technology Licensing, Llc | Actuator frame for scanning mirror |
CN109633893B (en) * | 2019-02-01 | 2024-05-14 | 西安知微传感技术有限公司 | Electromagnetic driving vibrating mirror |
CN111830701B (en) * | 2019-04-19 | 2022-02-15 | 华为技术有限公司 | Electromagnetic micromirror and laser device |
CN215932260U (en) * | 2020-08-14 | 2022-03-01 | 台湾东电化股份有限公司 | Optical element driving mechanism |
Citations (1)
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US6803938B2 (en) * | 2002-05-07 | 2004-10-12 | Texas Instruments Incorporated | Dynamic laser printer scanning alignment using a torsional hinge mirror |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
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EP1586933A4 (en) * | 2002-11-26 | 2006-02-22 | Brother Ind Ltd | Light scanner and image-forming apparatus |
JP4262574B2 (en) * | 2003-10-30 | 2009-05-13 | オリンパス株式会社 | Optical deflector |
KR101091129B1 (en) * | 2004-02-09 | 2011-12-09 | 세이코 엡슨 가부시키가이샤 | Mems scanner adapted to a laser printer |
US20070053045A1 (en) * | 2005-04-28 | 2007-03-08 | Texas Instruments Incorporated | Two sided torsional hinged mirror and method of manufacturing |
-
2005
- 2005-09-16 US US11/228,894 patent/US7187483B1/en active Active
-
2006
- 2006-09-18 CN CNA2006800425522A patent/CN101310207A/en active Pending
- 2006-09-18 WO PCT/US2006/036218 patent/WO2007035594A1/en active Application Filing
- 2006-09-18 EP EP06803751.4A patent/EP1949168B1/en not_active Expired - Fee Related
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6803938B2 (en) * | 2002-05-07 | 2004-10-12 | Texas Instruments Incorporated | Dynamic laser printer scanning alignment using a torsional hinge mirror |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20100002284A1 (en) * | 2008-07-02 | 2010-01-07 | Long-Sun Huang | Method of modulating resonant frequency of torsional mems device |
US20140118809A1 (en) * | 2011-07-06 | 2014-05-01 | Nec Corporation | Optical scanning device, image display apparatus and optical scanning method |
CN109683308A (en) * | 2019-02-01 | 2019-04-26 | 西安知微传感技术有限公司 | A kind of electromagnetic drive galvanometer reducing oscillating motion |
Also Published As
Publication number | Publication date |
---|---|
CN101310207A (en) | 2008-11-19 |
EP1949168A1 (en) | 2008-07-30 |
EP1949168B1 (en) | 2016-03-16 |
EP1949168A4 (en) | 2011-09-14 |
US7187483B1 (en) | 2007-03-06 |
WO2007035594A1 (en) | 2007-03-29 |
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