Microelectromechanical or/and nanoelectromechanical device with out-of-plane displacement having capacitive elements having a variable surface

Patent metadata

Field	Value
Publication number	US-11156459-B2
Application number	US-201715625314-A
Country	US
Kind code	B2
Filing date	Jun 16, 2017
Priority date	Jun 17, 2016
Publication date	Oct 26, 2021
Grant date	Oct 26, 2021

Abstract

Microelectromechanical sensor comprising a fixed part and a mobile part suspended from the fixed part such that the mobile part can move at least in an out-of-plane displacement direction, the fixed part comprising at least first electrodes extending parallel to the displacement direction of the mobile part, the mobile part comprising a seismic mass and at least second electrodes extending parallel to the out-of-plane displacement direction, the first electrodes and the second electrodes being located relative to each other so as to be interdigitated, in which the second electrodes are directly connected to the inertial mass and only part of the face of each mobile electrode is facing an electrode fixed at rest.

First claim

The invention claimed is:

1. A microelectromechanical and/or nanoelectromechanical device comprising:
at least two assemblies including a first assembly and a second assembly, wherein
the first assembly comprises at least one first part and at least one second part free to move relative to each other at least in an out-of-plane displacement direction,
the second assembly comprises at least one third part and at least one fourth part free to move relative to each other at least in the out-of-plane displacement direction,
the first part comprises a first support and at least first electrodes extending parallel to the out-of-plane displacement direction,
the second part comprises a second support and at least second electrodes extending parallel to said out-of-plane displacement direction,
the third part comprises a third support and at least third electrodes extending parallel to the out-of-plane displacement direction,
the fourth part comprises a fourth support and at least fourth electrodes extending parallel to said out-of-plane displacement direction,
the first electrodes and the second electrodes are arranged relative to each other such that they are interdigitated,
the third electrodes and the fourth electrodes are arranged relative to each other such that they are interdigitated,
the second support comprises at least one face perpendicular to the out-of-plane displacement direction,
the fourth support comprises at least one face perpendicular to the out-of-plane displacement direction,
the first electrodes each comprise a first end and a second end in the out-of-plane displacement direction,
the second electrodes each comprise a first end and a second end in the out-of-plane displacement direction,
the third electrodes each comprise a first end and a second end in the out-of-plane displacement direction,
the fourth electrodes each comprise a first end and a second end in the out-of-plane displacement direction,
the second ends of the second electrodes are directly connected to the face of the second support and a first end of the second electrodes is located between two ends of the first electrodes such that only part of a face of each of the second electrodes is facing a first electrode at rest,
the second ends of the fourth electrodes are directly connected to the face of the fourth support and a first end of the fourth electrodes is located between two ends of the third electrodes such that only part of a face of each of the second electrodes is facing a third electrode at rest,
the first part of the first assembly is mechanically connected to the fourth part of the second assembly and the second part of the first assembly is mechanically connected to the third part of the second assembly,
one of the first and second parts forms a first inertial mass,
one of the third and fourth parts comprises a set of second inertial masses, and
the set of second inertial masses surrounds the first inertial mass in a plan view in the out-of-plane displacement direction.

2. The device according to claim 1 , wherein
one of said first or second parts is mobile and the other of said first or second parts is fixed, and one of said third or fourth parts is mobile and the other of said third or fourth parts is fixed, or
said first and second parts are both mobile and displaced relative to each other, and said third and fourth parts are both mobile and displaced relative to each other.

3. The device according to claim 1 , wherein
one of said first or second parts is mobile and the other of said first or second parts is fixed, and
one of said third or fourth parts is mobile and the other of said third or fourth parts is fixed.

4. The device according to claim 1 , wherein a part of the first support forms an inertial mass which is suspended from the second part, a part of the second support forms an inertial mass which is suspended from the first part, a part of the third support forms an inertial mass which is suspended from the fourth part, or a part of the fourth support foil is an inertial mass which is suspended from the third part.

5. The device according to claim 1 , wherein
the first part of the first assembly and the fourth part of the second assembly are electrically insulated from each other, and/or
the second part of the first assembly and the third part of the second assembly are electrically insulated from each other.

6. The device according to claim 1 , wherein
the second support of the first assembly and the fourth support of the second assembly are located on one side of a plane perpendicular to the out-of-plane displacement direction, and
the first support of the first assembly and the third support of the second assembly are located on another side of said plane.

7. The device according to claim 6 , wherein
the second support forming an inertial mass of the first assembly comprises four housings to house four fourth supports of the second assembly,
the second electrodes of the first assembly form a cross between the four housings, and
the second assembly comprises four third supports suspended from the second support of the first assembly.

8. The device according to claim 1 , wherein
a cross-section of the first electrodes and the second electrodes are such that the first or the second electrodes continuously surround the second or first electrodes respectively, and
a cross-section of the third electrodes and the fourth electrodes are such that the third or the fourth electrodes continuously surround the fourth or third electrodes respectively.

9. The device according to claim 1 , further comprising:
at least one guiding means guiding the first part or the second part along the out-of-plane displacement direction.

10. The device according to claim 9 , wherein
the guiding means guides the first part or the second part in translation,
the guiding means comprises at least two rigid arms extending in a longitudinal direction, a first pivot articulation between each of the rigid arms and the first part or the second part, a second pivot articulation between each of the rigid arms and a support, and a coupling articulation between the two rigid arms comprising at least one third pivot articulation,
at least two of the first through third pivot articulations connected to each of the rigid arms have a degree of freedom in translation in a plane of the device along the rigid arms, and
said first through third pivot articulations have rotation axes at least parallel to each other such that, during translational displacement of the first part or the second part, the rigid arms pivot relative to each other in opposite directions.

11. The device according to claim 10 , wherein the least two of the first through third pivot articulations having the degree of freedom in translation in the plane of the device along the rigid aims comprise at least one beam that can be deformed in torsion.

12. The device according to claim 9 , wherein the guiding means is located at least along one external edge of a mobile element.

13. The device according to claim 9 , further comprising at least two guiding means,
wherein rotation axes of the two guiding means intersect each other.

14. A capacitive detection device comprising at least one device according to claim 1 .

15. An actuator comprising at least one device according to claim 1 .

16. The actuator according to claim 15 , wherein the mobile parts are suspended from the fixed parts by a pivot articulation.

17. A micromirror device comprising at least one actuator according to claim 15 , where

Assignees

• Commissariat Energie Atomique

Inventors

• Maspero Federico
• Joet Loic

Classifications

• B81B3/0051 Primary

  For defining the movement, i.e. structures that guide or limit the movement of an element (mechanical arrangements for preventing or damping vibration or shock H01H3/60) · CPC title

• B81B2203/053

  Translation according to an axis perpendicular to the substrate · CPC title

• B81B2201/033

  Comb drives · CPC title

• H01G5/14

  due to longitudinal movement of electrodes · CPC title

• G01C19/5762 Primary

  the sensing mass being connected to a driving mass, e.g. driving frames · CPC title