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
  • G02B26/085—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
• • 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
  • B81B3/004—Angular deflection
• • 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
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B81—MICROSTRUCTURAL TECHNOLOGY
  • B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
  • B81B2201/00—Specific applications of microelectromechanical systems
  • B81B2201/04—Optical MEMS
  • B81B2201/042—Micromirrors, not used as optical switches
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B81—MICROSTRUCTURAL TECHNOLOGY
  • B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
  • B81B2203/00—Basic microelectromechanical structures
  • B81B2203/01—Suspended structures, i.e. structures allowing a movement
  • B81B2203/0181—See-saws
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B81—MICROSTRUCTURAL TECHNOLOGY
  • B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
  • B81B2203/00—Basic microelectromechanical structures
  • B81B2203/05—Type of movement
  • B81B2203/058—Rotation out of a plane parallel to the substrate
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S359/00—Optical: systems and elements
  • Y10S359/904—Micromirror

Definitions

• the invention relates to a micromirror, in particular a micromirror mirror, according to the preamble of the main claim.
• a micromirror and in particular a micromirror mirror which is provided with an electrostatic drive has already been proposed in the application DE 198 57 946.2.
• a largely self-supporting mirror surface with two or possibly four spring bars or torsion bars opposite each other in pairs is connected to a surrounding supporting body.
• a micromirror with a magnetic drive is already known.
• a largely self-supporting membrane is also connected to a surrounding supporting body via two opposite torsion bars, conductor tracks in the form of conductor loops or windings being located on the underside of the mirror surface, through which an electric current can be passed, so that when an external magnetic field is applied, a Torque is exerted on the mirror surface.
• the object of the present invention was to develop a novel mirror design with increased mechanical load capacity, which is also particularly suitable for a magnetic drive.
• the increased mechanical load capacity is to be achieved in that the torsion bars or spring bars connecting the mirror surface to the supporting body are made stronger or more resilient to torsions and vibrations.
• the micromirror according to the invention has the advantage of a higher mechanical loading capacity and greater fracture stability, while at the same time relatively small electrical voltages are required in order to deflect the mirror surface from the rest position or to excite it to a torsional vibration.
• the mirror surface is connected to the supporting body via at least two torsion bars, which are at least approximately parallel and juxtaposed, with comparable bending strength compared to a single torsion bar, which takes up the entire width of the parallel torsion bar and the space between them , reduced torsional rigidity.
• the mirror surface is connected to the supporting body on two opposite sides in each case with two spaced-apart parallel torsion bars.
• a conductor track can be applied to the surface of each torsion bar, which can occupy the entire surface of the torsion bar, so that an optimal use of the width of the torsion bar results with simultaneous insulation of the conductor tracks from one another. It is thus particularly advantageously possible to conduct particularly high electrical currents of, for example, 10 mA to 1 A over the conductor tracks located on the surface of the torsion bars.
• the conductor tracks running on the surface of the torsion bars can now be made as wide as possible since the problem of electrical insulation from one another is eliminated.
• the design of the micromirror according to the invention now advantageously allows a more robust design of the torsion bars to be selected due to the greater forces that can be generated.
• the total width of the two torsion bars spaced parallel to one another, together with the width of the intermediate space between them, is greater than the width of a corresponding, single torsion bar known from the prior art.
• a torsional rigidity of the spring design according to the invention which is lower than the torsional rigidity of an individual torsion bar, which takes up the entire width of the two parallel torsion bars and the associated intermediate space.
• the spring design presented can also advantageously be transferred to micromirrors that have two mutually perpendicular torsion axes.
• the micromirror according to the invention can moreover be equipped with both an electrostatic and a magnetic drive.
• the provision of the actual mirror surface with two symmetrically attached loops in the outer region which leads to a significant increase in the magnetic flux enclosed by the conductor tracks guided on the surface of the mirror surface in an external magnetic field, finally has the advantage that these loops simultaneously act as Stop for the mirror surface can serve, and thus this and especially the torsion beam protects against bumps and short-term overloads.
• the loops strike the upper or lower side of the housing or the supporting body when the mirror surface is subjected to excessive torsion, and thus prevent the torsion bars from breaking.
• These additional loops on the mirror surface are particularly advantageous when the micromirror according to the invention is to be deflected statically and an air gap is provided between the mirror surface and the surrounding supporting body in order to achieve the smallest possible air vaporization.
• the micromirror according to the invention has the advantage of large driving forces with simultaneously low driving voltages, which at the same time results in improved stability of the micromirror and an increased yield in production, since the microstructures produced are overall more robust.
• the micromirror according to the invention can be produced entirely by means of production processes known per se, so that no new process steps and production technologies are required in production
• FIG. 1 shows a first exemplary embodiment of a micromirror with an electrostatic drive
• FIG. 2 shows a second embodiment with a magnetic drive
• FIG. 3 shows a third embodiment of a micromirror with a magnetic drive.
• FIG. 1 shows a micromirror 5, which is designed in the form of a micromirror mirror.
• the micromirror 5 shown has been structured out of a supporting body 11, 12 made of, for example, silicon in a manner known per se, a mirror surface 10 being provided in the form of a rectangle with dimensions of typically 100 ⁇ m ⁇ 100 ⁇ m to 400 ⁇ m ⁇ 400 ⁇ m , which is provided on two opposite sides with two parallel spaced torsion beams 13, 13 ⁇ .
• the torsion bars 13, 13 ⁇ which act as spring bars, connect the mirror surface 10 to the supporting body 11, 12, which surrounds the mirror surface, for example laterally and in the lower region, so that the mirror surface 10 is largely self-supporting.
• the supporting body 11, 12 is, for example, a silicon wafer.
• the torsion bars 13, 13 ⁇ also have a length of 10 ⁇ m to 100 ⁇ m, a height of 2 ⁇ m to 10 ⁇ m and a width of 5 ⁇ m to 15 ⁇ m. They are also arranged parallel to each other at a distance of 2 ⁇ m to 5 ⁇ m, so that there is a space corresponding to the distance between the torsion bars 13, 13 ⁇ .
• an electrode surface below the mirror surface 10 on which an electrode 18 is applied in regions in a manner known per se.
• an electrostatic force can be exerted between the mirror surface 10 and the electrode 18 such that a deflection of the mirror surface 10 about a torsion axis 17 occurs is parallel to the axis defined by the torsion bars 13, 13 x .
• Micromirror 5 for the electrical control and connection contact, should be dispensed with, since these details are known per se to the person skilled in the art.
• FIG. 2 shows an alternative embodiment of the exemplary embodiment according to FIG. 1, a magnetic drive now being used instead of an electrostatic drive.
• conductor tracks 15, 15 ⁇ are provided on the surface of the mirror surface 10 at least on one side, which are expediently guided on the outer edge of the mirror surface, so that they enclose as large an area as possible on the mirror surface 10.
• the conductor tracks 15, 15 ⁇ have been produced, for example, in a manner known per se by applying surface metallizations, for example made of gold, in regions. So that the conductor tracks 15, 15 ⁇ in FIG. 2 can carry the greatest possible electrical current, it is furthermore expedient to make the conductor tracks 15, 15 ⁇ as thick and flat as possible.
• the conductor tracks 15, 15 ⁇ are guided over the respectively assigned torsion bars 13 and 13 to electrical contact surfaces 14, 14, which are applied, for example, in a manner known per se to the supporting body 11, 12.
• the conductor tracks 15, 15 ⁇ each occupy the entire surface of the torsion bar 13 and 13 ⁇ respectively assigned to them.
• the electrical separation of the two conductor tracks 15, 15 ⁇ is ensured by the space between the torsion bars 13, 13 ⁇ .
• the thickness of the conductor tracks 15, 15 ⁇ is preferably 100 nm to 2 ⁇ m, but it can also reach 10 ⁇ m. Their width is expediently between 5 ⁇ m and 50 ⁇ m.
• the conductor tracks 15, 15 ⁇ are otherwise preferably made of gold.
• FIG. 2 it is further indicated by the symbol H that the micromirror 5 according to FIG. 2 is in an external magnetic field.
• an electrical current I therefore flows from for example 10 mA to 500 mA via the conductor tracks 15, 15 x , so that is explained by the
• Arrangement of the conductor tracks 15, 15 satisfies the requirements for the conductor tracks 15, 15 . Arrangement of the conductor tracks 15, 15 satisfies the requirements for the conductor tracks 15, 15 . Arrangement of the conductor tracks 15, 15 satisfies the requirements for the conductor tracks 15, 15 . Arrangement of the conductor tracks 15, 15 satisfies the requirements for the mirror surface 10.
• a torque T is thus exerted on the mirror surface 10 by the applied electrical current I and the external magnetic field H, where:
• This torque T which is proportional to the electrical current I present, the strength of the external magnetic field B or H and the area A enclosed by the conductor loop, thus causes the mirror area 10 to twist or twist about the torsion axis 17.
• the conductor tracks 15, 15 "are guided at least on one side on the surface of the mirror surface 10 in such a way that the largest possible in the external magnetic field H. magnetic flux from the conductor tracks 15, 15 ⁇ is included.
• FIG. 3 explains a further exemplary embodiment of the invention, which differs from FIG. 2 only in that the mirror surface 10 has lateral loops 16, 16 ⁇ due to a suitable structuring out of the supporting body 11, 12. These loops 16, 16 x are preferably arranged symmetrically and serve primarily to increase the torque T or the enclosed magnetic one
• the loops 16, 16 ⁇ according to FIG. 3 have, for example, an overall length of 500 ⁇ m to 1 mm and an overall width of 100 ⁇ m to 500 ⁇ m. Its thickness corresponds to the thickness of the mirror surface 10.
• the loops 16, 16 ⁇ are further formed similarly to the torsion bars 13, 13 ⁇ , that is to say they have the shape of narrow webs which enclose a space, the respectively assigned one on the surface of the webs Ladder- 15 or 15 ⁇ runs and this surface preferably completely covered.
• the conductor loop formed when the circuit is closed encloses a larger area overall, so that a significantly increased torque T can be generated with the same current I and the same external magnetic field H.
• the external magnetic field applied has a strength of preferably 1 mTesla to 1000 mTesla and is generated, for example, by a permanent or electromagnet arranged in the vicinity of the mirror surface 10.

Landscapes

• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Electromagnetism (AREA)
• Engineering & Computer Science (AREA)
• Computer Hardware Design (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Micromachines (AREA)
• Mechanical Light Control Or Optical Switches (AREA)
• Mechanical Optical Scanning Systems (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (2)

Family

ID=7934753

Family Applications (1)

Country Status (6)

Cited By (4)

Families Citing this family (53)

Family Cites Families (13)

• 1999
  • 1999-12-28 DE DE19963382A patent/DE19963382A1/de not_active Ceased
• 2000
  • 2000-11-22 ES ES00988634T patent/ES2228650T3/es not_active Expired - Lifetime
  • 2000-11-22 EP EP00988634A patent/EP1247131B1/de not_active Expired - Lifetime
  • 2000-11-22 WO PCT/DE2000/004116 patent/WO2001048527A2/de not_active Ceased
  • 2000-11-22 US US10/169,247 patent/US6749308B1/en not_active Expired - Lifetime
  • 2000-11-22 DE DE50007817T patent/DE50007817D1/de not_active Expired - Lifetime
  • 2000-11-22 JP JP2001549121A patent/JP4541627B2/ja not_active Expired - Lifetime

Also Published As

Similar Documents

Legal Events