Piezoelectric micro-electro-mechanical actuator device, movable in the plane

Patent metadata

Field	Value
Publication number	US-2018190895-A1
Application number	US-201715638195-A
Country	US
Kind code	A1
Filing date	Jun 29, 2017
Priority date	Dec 29, 2016
Publication date	Jul 5, 2018
Grant date	—

Abstract

A MEMS actuator device of a piezoelectric type formed on a substrate, with a base unit including a base beam element having a main extension in a extension plane and a thickness in a thickness direction perpendicular to the extension plane, smaller than the main extension. A piezoelectric region extends over the beam element. An anchor region is rigid to the base beam element and to the substrate. A base constraint structure is connected to one end of the base beam element and is configured to allow a deformation of the base beam element in the extension plane and substantially reduce a deformation of the base beam element in the thickness direction.

First claim

1 . A MEMS actuator device comprising:
a substrate; and a base unit, the base unit including:
a base beam element having a first end, a second end, a main extension in an extension plane and a thickness in a thickness direction that is perpendicular to the extension plane and smaller than the main extension;
a piezoelectric region on or in the base beam element;
an anchor region fixed with respect to the base beam element and to the substrate; and
a base constraint structure coupled to the second end of the base beam element, the base constraint structure being configured to allow a movement of the second end of the base beam element in the extension plane and prevent or substantially reduce a deformation of the base beam element in the thickness direction.

2 . The device according to claim 1 , wherein the base constraint structure includes a base constraint element that is undeformable in the thickness direction and a base hinge structure arranged between the base beam element and the base constraint element.

3 . The device according to claim 2 , wherein the base constraint element has a thickness greater than the base beam element.

4 . The device according to claim 2 , wherein the anchor region extends between the first end of the base beam element and the substrate, and the base constraint element includes a wall extending parallel to the base beam element and anchored to the substrate.

5 . The device according to claim 2 , wherein the base hinge structure includes a hinge region coupled to the second end of the base beam element and to the base constraint element, the hinge region having a smaller width than the base beam element and the constraint element and a thickness in the thickness direction greater than the base beam element.

6 . The device according to claim 1 , wherein the base unit is coupled to a first lateral unit through the base hinge structure, the first lateral unit being formed by a first lateral beam element and a first lateral constraint structure, the first lateral beam element having a main extension in the extension plane, a thickness in the thickness direction that is smaller than its main extension, a respective first end and a respective second end, and supporting a respective piezoelectric region, the first lateral constraint structure being rigid with the first end of the first lateral beam element and articulated to the second end of the first lateral beam element, the first lateral constraint structure being configured to allow a deformation of the first lateral beam element in the extension plane and prevent or substantially reduce a deformation of the first lateral beam element in the thickness direction.

7 . The device according to claim 6 , wherein the base unit is coupled to the first lateral unit through a base lever arm that is coupled to the base hinge structure and to the first lateral constraint structure.

8 . The device according to claim 7 , wherein the first lateral beam element extends, at rest, parallel to the base beam element, and the base lever arm extends, at rest, perpendicular to the base beam element.

9 . The device according to claim 8 , wherein the base hinge structure includes a first base hinge element arranged between the second end of the base beam element and an end of the base lever arm and a second base hinge element arranged between the end of the base lever arm and the base constraint structure, the first and second base hinge elements having respective thicknesses in the thickness direction greater than the base beam element and a width in the extension plane smaller than the base beam element and the base lever arm.

10 . The device according to claim 7 , wherein the first lateral unit includes a first lateral lever arm coupled to the second end of the first lateral beam element and coupled to the base lever arm.

11 . The device according to claim 10 , wherein the first lateral constraint structure includes a first lateral constrained arm and a first lateral hinge structure, the first lateral constrained arm extending, at rest, parallel to and at a distance from the first lateral beam element and having a first end rigidly coupled to the first end of the first lateral beam element and a second end coupled to the second end of the first lateral beam element through the first lateral hinge structure.

12 . The device according to claim 11 , wherein the first lateral hinge structure includes a first lateral hinge element arranged between the second end of the first lateral beam element and the first lateral lever arm and a second lateral hinge element arranged between the first lateral lever arm and the second end of the first lateral constrained arm, the first and second lateral hinge elements having respective thicknesses in the thickness direction greater than the first lateral beam element and a width in the extension plane smaller than the first lateral lever arm and the first lateral constrained arm.

13 . The device according to claim 10 , wherein the first lateral unit includes a second lateral lever arm coupled to the second end of the second lateral beam element on an opposite side to the first lateral lever arm, and the first lateral constraint structure further includes a second lateral constrained arm and a second lateral hinge structure, the second lateral constrained arm extending, at rest, parallel to and at a distance from the first lateral beam element and having a first end rigidly coupled to the first end of the first lateral beam element and a second end coupled to the second end of the first lateral beam element through the second lateral hinge structure.

14 . The device according to claim 13 , wherein the second lateral hinge structure includes a third lateral hinge element arranged between the second end of the first lateral beam element and the second lateral lever arm, and a fourth lateral hinge element arranged between the second lateral lever arm and the second end of the first lateral constrained arm, the third and fourth lateral hinge elements having respective thicknesses greater than the first lateral beam element and a width in the extension plane smaller than the second lateral lever arm and the second lateral constrained arm.

15 . The device according to claim 13 , wherein the first lateral unit is coupled to a second lateral unit through the second lateral lever arm, the second lateral unit being formed by a second lateral beam element and a second lateral constraint structure, the second lateral beam element having a main extension in the extension plane, a thickness in the thickness direction, a respective first end and a respective second end and supporting a respective piezoelectric region, the second lateral constraint structure being fixed with respect to the first end of the second lateral beam element and hinged to the second end of the second lateral beam element and to the first lateral unit, the second lateral constraint structure being configured to allow a deformation of the second lateral beam element in the extension plane and prevent or substantially reduce a deformation of the second lateral beam element in the thickness direction.

16 . The device according to claim 10 , further comprising a first connection arm rigidly coupled to the base lever arm and to the first lateral lever arm, the first lateral lever arm extending, at rest, parallel to and at a distance from the base lever arm, and the first connection arm extending, at rest, transverse to the base lever arm and to the first lateral lever arm between the base unit and the first lateral unit.

17 . The de

Assignees

• St Microelectronics Srl

Inventors

• Giusti Domenico
• Alessandri Anna

Classifications

• H01G5/18

  due to change in inclination, e.g. by flexing, by spiral wrapping · CPC title

• H01G5/38

  Multiple capacitors, e.g. ganged · CPC title

• H01L41/0946

  Electricity · mapped topic

• H01H2057/006

  Micromechanical piezoelectric relay · CPC title

• H01L41/0953 Primary

  Electricity · mapped topic