CAPACITIVE ACCELEROMETER

• US 20130074599A1
• Filed: 02/16/2012
• Published: 03/28/2013
• Est. Priority Date: 09/26/2011
• Status: Active Grant

• Current Assignee: RichWave Technology Corp
• Original Assignee: RichWave Technology Corp
• Inventors: Shen, Ching-Kai
• Granted Patent: US 8,910,523 B2
• Time in Patent Office: Days
• US Class Current: 73/514.32
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: G01P 15/18 in two or more dimensions
• CPC Class Codes: G01P 2015/082 for two degrees of freedom of movement of a single mass
• CPC Class Codes: G01P 2015/0831 the mass being of the paddle type having the pivot axis between the longitudinal ends of the mass, e.g. see-saw configuration

Abstract

A capacitive accelerometer includes a substrate and a first semiconductor layer. The first semiconductor layer is disposed on the substrate and includes a first mass, first and second support bases, first and second elastic members, and first and second comb capacitor sets. The first and second support bases are disposed at positions corresponding to first and second axes respectively. The first elastic member is connected to the first mass and the first support base in a manner of bending back and forth perpendicular to the first axis. The second elastic member is connected to the first mass and the second support base in a manner of bending back and forth perpendicular to the second axis. The first and second comb capacitor sets are disposed at positions corresponding to the second and first axes respectively and connected to the first mass. The first axis is perpendicular to the second axis.

Claims

1. A capacitive accelerometer comprising:

a substrate; and

a first semiconductor layer disposed on the substrate, the first semiconductor layer comprising;

a first mass;

at least one first support base located at least one side of the first mass corresponding to a first axis;

a first elastic member connected to the first mass and the first support base in a manner of bending back and forth perpendicular to the first axis, for making the first mass move elastically along the first axis when a force is applied to the first mass in the first axis;

at least one first combo capacitor set connected to at least one side of the first mass corresponding to a second axis;

at least one second support base located at least one side of the first mass corresponding to the second axis;

a second elastic member connected to the first mass and the second support base in a manner of bending back and forth perpendicular to the second axis, for making the first mass move elastically along the second axis when a force is applied to the first mass in the second axis; and

at least one second combo capacitor set connected to at least one side of the first mass corresponding to the first axis;

wherein the first axis is perpendicular to the second axis.

2. The capacitive accelerometer of claim 1, wherein the substrate has at least one sensing electrode and the capacitive accelerometer further comprises:

a second semiconductor layer disposed on the substrate and located at a side of the first second semiconductor layer, the second semiconductor layer comprising;

a second mass having a rotating shaft along the first axis or the second axis for generating a sensing capacity with the sensing electrode; and

at least one third support base connected to the rotating shaft for making the second mass asymmetrically disposed above the sensing electrode;

wherein the second mass is rotated relative to the rotating shaft when a force is applied to the second mass in a third axis, and the third axis is perpendicular to the first axis and the second axis.

3. The capacitive accelerometer of claim 1, wherein the first semiconductor layer comprises two first combo capacitor sets and each first combo capacitor set comprises:

a plurality of combo capacitor boards extendedly formed from the first mass; and

a plurality of fixed combo capacitor boards fixed to the substrate, arranged alternatively with the plurality of combo capacitor boards, and parallel to the plurality of combo capacitor boards;

wherein numbers of the combo capacitor board and the fixed combo capacitor board on the two first combo capacitor sets are different to each other.

4. The capacitive accelerometer of claim 1, wherein the first semiconductor layer comprises two first support bases and two first elastic members, each first elastic member is connected to the first mass and the corresponding first support base in a manner of bending back and forth perpendicular to the first axis, and the bending times of the two first elastic members are different to each other.

5. A capacitive accelerometer comprising:

a substrate; and

a first semiconductor layer disposed on the substrate, the first semiconductor layer comprising;

a first mass;

at least two first support bases respectively located at least one side of the first mass corresponding to a first axis;

two first elastic members respectively connected to the first mass and the first support base in a manner of bending back and forth parallel to the first axis, for making the first mass move elastically along a second axis when a force is applied to the first mass in the second axis;

at least one first combo capacitor set connected to at least one side of the first mass corresponding to the first axis;

at least two second support bases respectively located at least one side of the first mass corresponding to the first axis;

two second elastic members respectively connected to the first mass and the corresponding second support base in a manner of bending back and forth parallel to the second axis, for making the first mass move elastically along the first axis when a force is applied to the first mass in the first axis; and

at least one second combo capacitor set connected to at least one side of the first mass corresponding to the second axis;

wherein the bending times of the two first elastic members are different to each other, and the first axis is perpendicular to the second axis.

6. The capacitive accelerometer of claim 5, wherein the substrate has at least one sensing electrode and the capacitive accelerometer further comprises:

a second semiconductor layer disposed on the substrate and located at a side of the first second semiconductor layer, the second semiconductor layer comprising;

a second mass having a rotating shaft along the first axis or the second axis for generating a sensing capacity with the sensing electrode; and

at least one third support base connected to the rotating shaft for making the second mass asymmetrically disposed above the sensing electrode;

wherein the second mass is rotated relative to the rotating shaft when a force is applied to the second mass in a third axis, and the third axis is perpendicular to the first axis and the second axis.

7. The capacitive accelerometer of claim 5, wherein the first semiconductor layer comprises two first combo capacitor sets and each first combo capacitor set comprises:

a plurality of combo capacitor boards extendedly formed from the first mass; and

a plurality of fixed combo capacitor boards fixed to the substrate, arranged alternatively with the plurality of combo capacitor boards, and parallel to the plurality of combo capacitor boards;

wherein numbers of the combo capacitor board and the fixed combo capacitor board on the two first combo capacitor sets are different to each other.

8. A capacitive accelerometer comprising:

a substrate; and

a first semiconductor layer disposed on the substrate, the first semiconductor layer comprising;

a first mass;

at least one first support base located at least one side of the first mass corresponding to a first axis;

a first elastic member having a first bending structure and a first step structure, the first bending structure being connected to the first support base in a manner of bending back and forth corresponding to the first axis, the first step structure being connected between the first mass and the first bending structure;

at least one first combo capacitor set connected to at least one side of the first mass corresponding to the first axis;

at least one second support base located at least one side of the first mass corresponding to a second axis;

a second elastic member having a second bending structure and a second step structure, the second bending structure being connected to the second support base in a manner of bending back and forth corresponding to the second axis, the second step structure being connected between the first mass and the second bending structure; and

at least one second combo capacitor set connected to at least one side of the first mass corresponding to the second axis;

wherein the first axis is perpendicular to the second axis.

9. The capacitive accelerometer of claim 8, wherein a protruding block is respectively formed on the first mass corresponding to the first step structure and the second step structure.

10. The capacitive accelerometer of claim 8, wherein the substrate has at least one sensing electrode and the capacitive accelerometer further comprises:

a second semiconductor layer disposed on the substrate and located at a side of the first second semiconductor layer, the second semiconductor layer comprising;

a second mass having a rotating shaft along the first axis or the second axis for generating a sensing capacity with the sensing electrode; and

at least one third support base connected to the rotating shaft for making the second mass asymmetrically disposed above the sensing electrode;

wherein the second mass is rotated relative to the rotating shaft when a force is applied to the second mass in a third axis, and the third axis is perpendicular to the first axis and the second axis.

11. The capacitive accelerometer of claim 8, wherein the first semiconductor layer comprises two first combo capacitor sets and each first combo capacitor set comprises:

a plurality of combo capacitor boards extendedly formed from the first mass;

a plurality of fixed combo capacitor boards fixed to the substrate, arranged alternatively with the plurality of combo capacitor boards, and parallel to the plurality of combo capacitor boards;

wherein numbers of the combo capacitor board and the fixed combo capacitor board on the two first combo capacitor sets are different to each other.

12. The capacitive accelerometer of claim 8, wherein the first bending structure is connected between the first support base and the first step structure in a manner of bending back and forth perpendicular to the first axis and the second bending structure is connected between the second support base and the second step structure in a manner of bending back and forth perpendicular to the second axis.

13. The capacitive accelerometer of claim 8, wherein the first bending structure is connected between the first support base and the first step structure in a manner of bending back and forth parallel to the first axis, and the second bending structure is connected between the second support base and the second step structure in a manner of bending back and forth parallel to the second axis.

14. The capacitive accelerometer of claim 8, wherein the first semiconductor layer comprises two first support bases and two first elastic members, each first bending structure is connected between the first mass and the corresponding first support base in a manner of bending back and forth corresponding to the first axis, and the bending times of the two first bending structures are different to each other.

15. A capacitive accelerometer comprising:

a substrate; and

a first semiconductor layer disposed on the substrate, the first semiconductor layer comprising;

a first mass;

at least two first combo capacitor sets connected to least one side of the first mass corresponding to a first axis;

at least one first support base disposed between the two first combo capacitor sets;

a first elastic member connected between the first mass and the first support base in a manner of bending back and forth corresponding to the first axis;

at least two second combo capacitor sets connected to at least one side of the first mass corresponding to a second axis;

at least one second support base disposed between the two second combo capacitor sets; and

a second elastic member connected between the first mass and the second support base in a manner of bending back and forth corresponding to the second axis;

wherein the first axis is perpendicular to the second axis.

16. The capacitive accelerometer of claim 15, wherein the substrate has at least one sensing electrode and the capacitive accelerometer further comprises:

a second semiconductor layer disposed on the substrate and located at a side of the first second semiconductor layer, the second semiconductor layer comprising;

a second mass having a rotating shaft along the first axis or the second axis for generating a sensing capacity with the sensing electrode; and

at least one third support base connected to the rotating shaft for making the second mass asymmetrically disposed above the sensing electrode;

wherein the second mass is rotated relative to the rotating shaft when a force is applied to the second mass in a third axis, and the third axis is perpendicular to the first axis and the second axis.

17. The capacitive accelerometer of claim 15, wherein the first semiconductor layer comprises two first combo capacitor sets and each first combo capacitor set comprises:

a plurality of combo capacitor boards extendedly formed from the first mass;

a plurality of fixed combo capacitor boards fixed to the substrate, arranged alternatively with the plurality of combo capacitor boards, and parallel to the plurality of combo capacitor boards;

wherein numbers of the combo capacitor board and the fixed combo capacitor board on the two first combo capacitor sets are different to each other.

18. The capacitive accelerometer of claim 15, wherein the first elastic member is connected between the first support base and the first mass in a manner of bending back and forth perpendicular to the first axis, and the second elastic member is connected between the second support base and the second mass in a manner of bending back and forth perpendicular to the second axis.

19. The capacitive accelerometer of claim 15, wherein the first elastic member is connected between the first support base and the first mass in a manner of bending back and forth parallel to the first axis, and the second elastic member is connected between the second support base and the second mass in a manner of bending back and forth parallel to the second axis.

20. The capacitive accelerometer of claim 15, wherein the first semiconductor layer comprises two first support bases and two first elastic members, each first elastic member is connected between the first mass and the corresponding first support base in a manner of bending back and forth corresponding to the first axis, and the bending times of the two first elastic members are different to each other.