Excitation in Micromechanical Devices

• US 20070111362A1
• Filed: 10/06/2006
• Published: 05/17/2007
• Est. Priority Date: 11/04/2005
• Status: Active Grant

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies Sensonor AS (Infineon Technologies AG)
• Inventors: Westby, Eskild
• Granted Patent: US 7,637,158 B2
• Time in Patent Office: Days
• US Class Current: 438/50
• CPC Class Codes: G01C 19/5712 the devices involving a micromechanical structure
• CPC Class Codes: G01C 19/5769 Manufacturing; Mounting; Housings

Abstract

A resonant structure for a micromechanical device includes a crystalline silicon beam and at least one mass attached to the beam. An excitation plane of the resonant structure is defined by the predominant motion of the excited resonant structure. The beam includes crystal axes aligned such that none of the crystal axes are parallel to the length of the beam and/or none of the crystal axes are normal to the excitation plane.

Claims

1. A resonant structure for a micromechanical device, the resonant structure comprising:

a crystalline silicon beam; and

at least one mass attached to the beam;

wherein motion of the resonant structure predominantly occurs within an excitation plane, and the beam includes crystal axes aligned such that no crystal axis is parallel to the length of the beam and/or no crystal axis is normal to the excitation plane.

2. The resonant structure according to claim 1, wherein the resonant structure comprises a sensing element.

3. A micromechanical device comprising:

at least one resonant structure according to claim 1;

and

an excitation component arranged to excite motion of the resonant structure.

4. The micromechanical device according to claim 3, wherein the device comprises a sensing device and the excitation component is arranged to excite motion of the sensing element in a direction normal to the excitation plane, and the device further comprises a detection component arranged to detect motion in a direction normal to the excitation plane not caused by the excitation component.

5. The micromechanical device according to claim 3, wherein the resonant structure is arranged to be excitable to a predominantly rotational excitation mode.

6. The micromechanical device according to claim 3, wherein the device comprises a power generation device and the resonant structure is arranged to be excitable to a predominantly rotational excitation mode, the resonant structure is fixed to a wheel such that, during use, a rotational axis of the excited resonant structure is substantially perpendicular to a rotational axis of the wheel, and the micromechanical device further comprises a power extraction component configured to generate power via converting Coriolis motion of the excited resonant structure.

7. The micromechanical device according to claim 3, wherein the excitation component is arranged to electrostatically excite motion of the resonant structure.

8. A method of exciting a resonant structure in an excitation plane in a micromechanical device, the method comprising:

providing a resonant structure comprising a crystalline silicon beam including crystal axes aligned such that no crystal axis is parallel to the length of the beam and/or no crystal axis is normal to the excitation plane; and

exciting motion of the resonant structure in a direction normal to the excitation plane.