Rotation sensing apparatus and method for manufacturing the same

• US 20060156812A1
• Filed: 01/05/2005
• Published: 07/20/2006
• Est. Priority Date: 01/05/2005
• Status: Active Grant

• Current Assignee: Industrial Technology Research Institute
• Original Assignee: Industrial Technology Research Institute
• Inventors: Ming-Hsiu, Hsu, Kai-Cheng, Chang, Pei-Fang, Liang, Yi-Ru, Chen, Ya-Ping, Chen
• Granted Patent: US 7,155,976 B2
• Time in Patent Office: Days
• US Class Current: 73/504.120
• CPC Class Codes: G01C 19/5719 using planar vibrating masses driven in a translation vibration along an axis

Abstract

The invention provides a rotation sensing apparatus and method for manufacturing the same, in which the rotation sensing apparatus comprises at least a pair of vibration parts and a sensing electrode. The pair of vibration parts is disposed on a substrate symmetrically and each vibration part comprises an electrostatic vibrating body, a fixed support and an elastic body. The electrostatic vibrating body is away from the substrate with an appropriate distance. The fixed support connects with the electrostatic vibrating body and the substrate. The elastic body connects the fixed support with some rods thereof and connects with the electrostatic vibrating body with some other rods thereof. The sensing electrode is disposed on the substrate and under the at least pair of vibration parts. The pair of vibration parts can vibrate horizontally by electrostatic force and will sway vertically to the substrate by Coriolis force when a rotation occurs. The rotation can be measured by detecting the change of capacitance between the electrostatic vibrating body and the sensing electrode.

Claims

1. A rotation sensing apparatus, comprising:

at least a pair of vibration parts disposed on a substrate symmetrically, each vibration part comprises;

an electrostatic vibrating body, which is a conductor and is away from the substrate with an appropriate distance, the electrostatic vibrating body is electrically connected to a driving circuit;

a fixed support, which connects with the electrostatic vibrating body and the substrate;

an elastic body, which connects the fixed support with some rods thereof and connects with the electrostatic vibrating body with some other rods thereof; and

a sensing electrode disposed on the substrate and under the at least pair of vibration parts.

2. The rotation sensing apparatus of claim 1, wherein the electrostatic vibrating body further comprises a plurality of mass bodies separated with each other and disposed on the electrostatic vibrating body.

3. The rotation sensing apparatus of claim 2, wherein the plurality of mass bodies are made of a conductor material or a semiconductor material.

4. The rotation sensing apparatus of claim 1, wherein each vibration part further comprises a feedback electrode for a closed loop control when driving the electrostatic vibrating bodies to vibrate.

5. The rotation sensing apparatus of claim 4, wherein the feedback electrode is a comb electrode structure mutually interlaced with a feedback comb drive of each electrostatic vibrating body.

6. The rotation sensing apparatus of claim 1, further comprising a driving circuit for providing the electrostatic vibrating bodies with an electric field such that the electrostatic vibrating bodies vibrate due to electrostatic forces.

7. The rotation sensing apparatus of claim 6, wherein the electric field is generated by a periodic electrical signal.

8. The rotation sensing apparatus of claim 1, further comprising a sensing circuit connected to the sensing electrode for detecting capacitance variations between the electrostatic vibrating bodies and the sensing electrode.

9. The rotation sensing apparatus of claim 1, wherein the at least pair of vibration parts comprising a first pair of vibration parts and a second pair of vibration parts and the first pair of vibration parts is orthogonal to the second pair of vibration parts.

10. The rotation sensing apparatus of claim 9, wherein the first pair of vibration parts can detect rotations of a first axis and the second pair of vibration parts can detect rotations of a second axis.

11. The rotation sensing apparatus of claim 9, wherein at least one side adjacent to the first pair of vibration parts and the second pair of vibration parts has a mutually interlaced comb electrode structure.

12. The rotation sensing apparatus of claim 1, wherein the at least pair of vibration parts comprising four pairs of vibration parts for detecting rotations of a first axis, a second axis, and a third axis.

13. The rotation sensing apparatus of claim 1, wherein the elastic body comprises multiple long rods.

14. The rotation sensing apparatus of claim 1, wherein the electrostatic vibrating body has a symmetrical center line through the connecting position of the elastic body and the fixed support and along the long rods of the elastic body.

15. A method for manufacturing a rotation sensing apparatus, comprising the following steps:

(a) forming a first conducting layer on a substrate;

(b) forming an insulating layer on the first conducting layer;

(c) removing a part of the insulating layer on the first conducting layer to form a trough;

(d) forming a sacrificial layer on the insulating layer and filling the trough;

(e) removing the sacrificial layer filled in the trough to expose the first conducting layer and form a contact hole;

(f) forming a second conducting layer on the sacrificial layer and filling the contact hole;

(g) etching a part of the second conducting layer to form at least a pair of electrostatic vibrating structures; and

(h) removing the sacrificial layer.

16. The method for manufacturing a rotation sensing apparatus of claim 15, a step of forming at least an inertial array layer on the at least pair of electrostatic vibrating structures is further comprised between the steps of (g) and (h).

17. The method for manufacturing a rotation sensing apparatus of claim 16, the inertial array layer is made of a conductor material or a semiconductor material.

18. The method for manufacturing a rotation sensing apparatus of claim 17, the conductor material is gold (Au).

19. The method for manufacturing a rotation sensing apparatus of claim 15, the sacrificial layer is made of SiO₂.

20. The method for manufacturing a rotation sensing apparatus of claim 15, the insulating layer is made of Si₃N₄.