Micromechanical device

Patent metadata

Field	Value
Publication number	US-9164277-B2
Application number	US-201313938276-A
Country	US
Kind code	B2
Filing date	Jul 10, 2013
Priority date	Jan 14, 2011
Publication date	Oct 20, 2015
Grant date	Oct 20, 2015

Abstract

The force on the electrodes of an electrostatic field is used so that lateral tensile or compressive forces result which can deform a deformable element or can strongly deflect a deflectable structure. For this, a micromechanical device includes, apart from an electrode and a deformable element, an insulating spacer layer via which the electrode is fixed to the deformable element, wherein the insulating spacer layer is structured into several spaced-apart segments along a lateral direction, so that by applying an electric voltage between the electrode and the deformable element lateral tensile or compressive forces bending the deformable element along the lateral direction result. Thereby, the problem that normally accompanies electrostatic drives, namely the problem of the pull-in effect, is overcome. The deflection of the deformable element can be much larger than the gaps of the two electrodes, i.e. the above-mentioned electrode and the deformable element. A usage as a sensor is also possible.

First claim

The invention claimed is:

1. A micromechanical device, comprising
an electrode;
a deformable element; and
an insulating spacer layer,
wherein the electrode is fixed to the deformable element via the insulating spacer layer, and
wherein

the insulating spacer layer is structured into several spaced-apart segments along a lateral direction, so that by applying an electric voltage between the electrode and the deformable element an area force acting in a thickness direction is applied to the electrode and the deformable element, as a consequence of which lateral tensile or compressive forces result that bend the deformable element along the lateral direction according to the bimorph principle.

2. The micromechanical device according to claim 1 , wherein the segments each comprise a longitudinal extension direction running transversely to the lateral direction.

3. The micromechanical device according to claim 2 , wherein the segments and the gaps between the same are stripe-shaped.

4. The micromechanical device according to claim 1 , wherein a periodicity of the structuring of the insulating spacer layer is approximately constant in the lateral direction across an area via which the electrode and the deformable element oppose one another.

5. The micromechanical device according to claim 1 , wherein the deformable element is a plate, a bowl, a membrane, a beam or a bar.

6. The micromechanical device according to claim 1 , wherein the deformable element is suspended and clamped such that it remains unbent by applying an electric voltage along a lateral direction perpendicular to the lateral direction, or is bent also in a same direction as along the lateral direction.

7. The micromechanical device according to claim 1 , which is formed in a substrate, wherein the electrode is fixed in a substrate direction above or below the deformable element, so that by bending the deformable element the same is bend out of the substrate plane, wherein the insulating spacer layer runs parallel to the substrate plane.

8. The micromechanical device according to claim 1 , which is formed in a substrate, wherein the electrode is laterally fixed to the deformable element, so that by bending the deformable element the same is bent within a substrate plane of the substrate, wherein the insulating spacer layer runs transversely to the substrate plane.

9. The micromechanical device according to claim 1 , wherein the electrode is a first electrode and the micromechanical device comprises a further electrode fixed to the side of the first electrode facing away from the deformable element via a further insulating spacer layer, wherein the further insulating spacer layer is structured into several spaced-apart segments along the lateral direction.

10. The micromechanical device according to claim 9 , wherein the spacer layer is a first insulating spacer layer and the segments of the further insulating spacer layer are positioned laterally in gaps of the segments of the first insulating spacer layer.

11. The micromechanical device according to claim 1 , wherein the electrode is a first electrode and the micromechanical device comprises a further electrode fixed to a side of the deformable element facing away from the first electrode via a further insulating spacer layer, wherein the further insulating spacer layer is structured into several spaced-apart segments along the lateral direction, so that by applying an electric voltage between the first electrode and the deformable element lateral tensile or compressive forces result that bend the deformable element along the lateral direction in a first direction, while by applying an electric voltage between the second electrode and the deformable element either the same of lateral tensile or compressive forces result that bend the deformable element along the lateral direction also in the first direction, or the other of the lateral or compressive forces that bend the deformable element along the lateral direction in a direction opposing the first.

12. The micromechanical device according to claim 1 , wherein a thickness of the insulating spacer layer is between 100 nm to 5 μm, each inclusively.

13. The micromechanical device according to claim 1 , wherein the deformable element is made of a conductive material, is made locally conductive or coated with a conductive material.

14. The micromechanical device according to claim 1 , wherein the electrode is formed in a planar manner and respectively curved away from the deformable element between the segments.

15. The micromechanical device according to claim 1 , wherein the electrode is formed in a planar manner and respectively curved towards the deformable element between the segments.

16. The micromechanical device according to claim 1 , wherein the electrode is formed in a planar manner and respectively comprises a V-shaped cross-section in a plane between the segments, which is spanned by the lateral direction and a thickness direction of the insulating spacer layer.

17. The micromechanical device according to claim 1 , wherein a surface of the deformable element facing the electrode is respectively formed curved away from the electrode between the segments.

18. The micromechanical device according to claim 1 , wherein a surface of the deformable element facing the electrode is respectively formed curved towards the electrode between the segments.

19. The micromechanical device according to claim 1 , wherein the electrode and a surface of the deformable element facing the electrode are respectively formed between the segments such that gaps therebetween comprise the same cross-section in a plane spanned by the lateral direction and a thickness direction of the insulating spacer layer.

20. The micromechanical device according to claim 1 comprising a driver circuit for applying the voltage to the micromechanical device, so that the micromechanical device acts as a micromechanical actuator.

21. The micromechanical device according to claim 1 , wherein the deformable element forms a spring portion between a suspension location and a functional element of the micromechanical device.

22. The micromechanical device according to claim 21 , wherein the functional element comprises a plate tiltably suspended around a tilting axis, and the spring portion forms a first distributed spring of the micromechanical device, which extends opposite to a second distributed spring of the micromechanical device along a circumference of the plate from a torsion spring of the micromechanical device, which extends along the tilting axis to a mounting location at the circumference of the plate, namely symmetrically to the second distributed spring.

23. The micromechanical device according to claim 22 , further comprising a further electrode fixed to the second distributed spring via a further spacer layer, such that in the first distributed spring the insulating spacer layer is structured such that by applying an electric voltage between the electrode and the deformable element lateral tensile and compressive forces result that bend the first distributed spring relative to the plate in a first normal direction, and wherein in the second distributed spring the insulating spacer layer is structured such that by applying an electric voltage between the electrode and the deformable element lateral tensile and compressive forces result that bend the second distributed spring relative to the plate in a second normal direction opposing

Assignees

• Fraunhofer Ges Forschung

Inventors

• Conrad Holger
• Schenk Harald
• Schirrmann Christian
• Sandner Thilo
• Zimmer Fabian
• Schmidt Jan-Uwe

Classifications

• H02N1/006

  of the gap-closing type (H02N1/004 takes precedence) · CPC title

• H04N1/08

  Mechanisms for mounting or holding the sheet around the drum · CPC title

• G02B26/0825 Primary

  the reflecting element being a flexible sheet or membrane, e.g. for varying the focus (flexible mirrors for cosmetic use A45D42/24) · CPC title

• G02B26/0841 Primary

  the reflecting element being moved or deformed by electrostatic means · CPC title

• H01G5/16

  using variation of distance between electrodes · CPC title