Micromechanical piezoelectric actuators for implementing large forces and deflections

Patent metadata

Field	Value
Publication number	US-10349182-B2
Application number	US-201715448846-A
Country	US
Kind code	B2
Filing date	Mar 3, 2017
Priority date	Sep 5, 2014
Publication date	Jul 9, 2019
Grant date	Jul 9, 2019

Abstract

A MEMS includes a diaphragm, a stroke structure coupled to the diaphragm, and at least two piezoelectric actuators coupled to a plurality of mutually spaced-apart contact points of the stroke structure via a plurality of mutually spaced-apart connecting elements, the at least two piezoelectric actuators being configured to cause a stroke movement of the stroke structure so as to deflect the diaphragm.

First claim

The invention claimed is:

1. A MEMS comprising:
a diaphragm;
a stroke structure coupled to the diaphragm; and
at least two piezoelectric actuators coupled to a plurality of mutually spaced-apart contact points of the stroke structure via a plurality of mutually spaced-apart connecting elements;
the at least two piezoelectric actuators being configured to cause a stroke movement of the stroke structure so as to deflect the diaphragm; and
wherein each of the at least two piezoelectric actuators is connected to at least two mutually spaced-apart contact points of the stroke structure via at least two mutually spaced-apart connecting elements.

2. The MEMS as claimed in claim 1 , wherein the plurality of mutually spaced-apart connecting elements are connected to a plurality of mutually spaced-apart contact points of the at least two piezoelectric actuators.

3. The MEMS as claimed in claim 1 , wherein the stroke structure spans, perpendicularly to a direction of the stroke movement, an area which corresponds to at least 30% of an area of the diaphragm.

4. The MEMS as claimed in claim 1 , wherein the stroke structure is coupled to the diaphragm via a plurality of regions arranged in a distributed manner.

5. The MEMS as claimed in claim 1 , wherein a cross-sectional area of the stroke structure that is perpendicular to a direction of the stroke movement of the stroke structure is smaller than a sum of piezoelectrically active actuator areas of the at least two piezoelectric actuators.

6. The MEMS as claimed in claim 1 , wherein the stroke structure comprises a plurality of stroke bodies.

7. A system comprising:
a MEMS as claimed in claim 1 ; and
a controller configured to control the at least two piezoelectric actuators of the MEMS;
the MEMS comprising at least one piezoelectric position sensor configured to provide a sensor signal dependent on the deflection of the diaphragm; and
the controller being configured to control the at least two piezoelectric actuators of the MEMS in a regulated manner on the basis of the sensor signal.

8. A utilization of the MEMS as claimed in claim 1 for sound generation, for ultrasound generation, for displacing liquids, for displacing gasses, or for generating droplets of liquid.

9. A MEMS loudspeaker for generating sound waves within the audible wavelength spectrum, comprising
a diaphragm,
a stroke structure coupled to the diaphragm, and
at least two piezoelectric actuators,
by means of which a stroke movement of the stroke structure can be caused for deflecting the diaphragm,
wherein
the piezoelectric actuators are connected to a plurality of mutually spaced-apart contact points of the stroke structure via a plurality of mutually spaced-apart flexible connecting elements, and that each of the at least two piezoelectric actuators is connected to at least two mutually spaced-apart contact points of the stroke structure via at least two mutually spaced-apart connecting elements.

10. The MEMS loudspeaker as claimed in claim 9 , wherein the diaphragm is connected to the stroke structure at a front end of the stroke structure in a direct manner, and/or the piezoelectric actuators are connected to the stroke structure on at least one side face of the stroke structure, in particular on two opposite side faces, in an indirect manner via the connecting elements.

11. The MEMS loudspeaker as claimed in claim 9 , wherein the plurality of connecting elements that are mutually spaced-apart in particular in the transverse direction of the MEMS loudspeaker are connected to a plurality of mutually spaced-apart contact points of the at least two piezoelectric actuators.

12. The MEMS loudspeaker as claimed in claim 9 , wherein the stroke structure is coupled to the diaphragm via a plurality of regions arranged along at least two at least partly mutually spaced-apart straight lines or curves.

13. A MEMS loudspeaker for generating sound waves within the audible wavelength spectrum, comprising
a diaphragm,
a stroke structure coupled to the diaphragm, and
at least one piezoelectric actuator by means of which a stroke movement of the stroke structure can be caused for deflecting the diaphragm,
wherein
the MEMS loudspeaker comprises at least one position sensor configured to provide a sensor signal dependent on the deflection of the diaphragm, and that each of the at least two piezoelectric actuators is connected to at least two mutually spaced-apart contact points of the stroke structure via at least two mutually spaced-apart connecting elements.

14. The MEMS loudspeaker as claimed in claim 13 , wherein the actuator is configured to be operated in a regulated manner as a function of the sensor signal by means of a controller provided therefor;
or that the position sensor is integrated in the actuator;
or that the sensor electrodes of the integrated position sensor are configured as two-dimensional or interdigital electrodes and/or are electrically insulated from the actuator electrodes;
or that the piezoelectric position sensor and the piezoelectric actuator are configured by a common piezoelectric layer.

15. A regulating unit for operating a MEMS loudspeaker in a regulated manner, comprising a MEMS loudspeaker as claimed in claim 13 , and
a controller configured to control a piezoelectric actuator of the MEMS loudspeaker,
wherein
the MEMS loudspeaker comprises at least one piezoelectric position sensor configured to provide the controller with a sensor signal dependent on the deflection of a diaphragm of the MEMS loudspeaker, and
in that the controller is configured to control the at least one piezoelectric actuator of the MEMS loudspeaker in a regulated manner on the basis of the sensor signal.

Assignees

• Fraunhofer Ges Forschung

Inventors

• Stoppel Fabian
• Wagner Bernhard

Classifications

• H04R17/00 Primary

  Piezoelectric transducers; Electrostrictive transducers (piezoelectric or electrostrictive elements in general H10N30/00; details of piezoelectric or electrostrictive motors, generators or positioners {H10N30/00}) · CPC title

• H04R3/002

  Damping circuit arrangements for transducers, e.g. motional feedback circuits · CPC title

• H04R2201/003

  Mems transducers or their use · CPC title

• H04R29/001

  for loudspeakers (H04R29/007 takes precedence) · CPC title

• H01L41/0946

  Electricity · mapped topic