Rotation rate sensor

• US 9,909,874 B2
• Filed: 04/07/2014
• Issued: 03/06/2018
• Est. Priority Date: 04/11/2013
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Reinmuth, Jochen
• Primary Examiner(s): Kwok, Helen
• Application Number:
  US14/783,792
• Publication Number:
  US 20160047654A1
• Time in Patent Office: 1,429 Days
• CPC Class Codes: G01C 19/5712 the devices involving a micromechanical structure
• CPC Class Codes: G01C 19/5719 using planar vibrating masses driven in a translation vibration along an axis
• CPC Class Codes: G01C 19/574 the devices having two sensing masses in anti-phase motion

Abstract

A micromechanical rotation rate sensor includes: a substrate having a main plane of extension; a first Coriolis element; a second Coriolis element; a drive device for deflecting the first and second Coriolis elements from a neutral position; and a detection device. The first Coriolis element, with regard to a first axis extending in parallel to the main plane of extension, has a mass-symmetrical design with respect to the second Coriolis element. The first and second Coriolis elements have a common main plane of extension, and in the neutral position the shared main plane of extension extends in parallel to the main plane of extension of the substrate. The first and second Coriolis elements each have a mass-symmetrical design with respect to a second axis extending perpendicularly with respect to the first axis. The first and second Coriolis elements are drivable by the drive device.

Claims

1. A micromechanical structure configured as a rotation rate sensor, comprising:

a substrate having a main plane of extension;

a first Coriolis element;

a second Coriolis element;

at least one drive device for deflecting the first Coriolis element and the second Coriolis element from a neutral position;

at least one detection device;

at least one first deflection element; and

at least one second deflection element;

wherein;

the first Coriolis element, with regard to a first axis extending in parallel to the main plane of extension, has a mass-symmetrical design with respect to the second Coriolis element;

the first Coriolis element and the second Coriolis element have a common main plane of extension;

in the neutral position the common main plane of extension extends in parallel to the main plane of extension of the substrate;

the first Coriolis element and the second Coriolis element each have a mass-symmetrical design with respect to a second axis extending perpendicularly with respect to the first axis;

the first Coriolis element and the second Coriolis element being drivable by the drive device to undergo a rotational vibration about the first axis;

in the case of a rotation rate acting in parallel to the projection of the second axis onto the main plane of extension to provide an action of force of a Coriolis force, in the sense of a rotational vibration, the first Coriolis element and the second Coriolis element being deflectable about a third axis extending perpendicularly with respect to the main plane of extension and extending through an intersection point of the first axis and the second axis;

the first deflection element and the second deflection element having a mass-symmetrical design with respect to the first axis and with respect to the second axis;

the first deflection element is coupled at least to the first Coriolis element, and the second deflection element is coupled at least to the second Coriolis element, in such a way that the action of force of the Coriolis force on the first Coriolis element and on the second Coriolis element, in the sense of a rotational vibration of the first deflection element and of the second deflection element about the third axis, is detectable by the detection device;

the drive device includes electrodes having a main plane of extension in parallel to the main plane of extension of the substrate and being located between the substrate and at least one of the first and second Coriolis elements, a distance of the drive device from the first axis being less than 40% of the extension of at least one of the first and second Coriolis elements along the second axis; and

coupling of the first deflection element to the first Coriolis element and of the second deflection element to the second Coriolis element is hard with regard to a rotational vibration about the third axis.

2. The micromechanical structure as recited in claim 1, wherein the first axis includes at least one torsion spring, a length of the torsion spring being greater than a height of the torsion spring, and the height of the torsion spring being greater than a width of the torsion spring.

3. The micromechanical structure as recited in claim 2, wherein the micromechanical structure is formed by a surface micromechanical process.

4. The micromechanical structure as recited in claim 1, wherein the detection device includes electrodes.

5. The micromechanical structure as recited in claim 4, wherein the detection device includes first finger electrodes situated in a comb structure, the first deflection element and the second deflection element including second finger electrodes which mesh with the first finger electrodes.

6. The micromechanical structure as recited in claim 1, wherein at least one of:

the detection device is situated circumferentially around at least one central substrate suspension;

the first Coriolis element and the second Coriolis element are situated circumferentially around at least one central substrate suspension; and

the first deflection element and the second deflection element are situated circumferentially around at least one central substrate suspension.

7. The micromechanical structure as recited in claim 1, wherein:

the first Coriolis element includes multiple segments, adjacent segments of the first Coriolis element being coupled by torsion springs; and

the second Coriolis element includes multiple segments, adjacent segments of the second Coriolis element being coupled by torsion springs.

8. The micromechanical structure as recited in claim 1, wherein the substrate has recesses which enable the first Coriolis element and the second Coriolis element to have a larger maximum deflection angle of a rotational vibration than is the case without the recesses.

9. The micromechanical structure as recited in claim 1, wherein:

coupling of the first Coriolis element and of the second Coriolis element with the substrate is (i) soft with regard to a rotational vibration about the first axis and with regard to a rotational vibration about the third axis, and (ii) is hard with regard to a rotational vibration about the second axis;

coupling of the first deflection element and of the second deflection element to the substrate is (iii) soft with regard to a rotational vibration about the third axis, and (iv) hard with regard to a rotational vibration about the first axis and with regard to a rotational vibration about the second axis; and

coupling of the first deflection element to the first Coriolis element and of the second deflection element to the second Coriolis element is (v) soft with regard to a rotational vibration about the first axis, and (vi) is hard with regard to a rotational vibration about the second axis.