INERTIA MEASUREMENT MODULE AND TRIAXIAL ACCELEROMETER

• US 20170363655A1
• Filed: 07/23/2015
• Published: 12/21/2017
• Est. Priority Date: 12/25/2014
• Status: Active Grant

• Current Assignee: Weifang Goertek Microelectronics Co., Ltd. (Goertek Incorporated)
• Original Assignee: Goertek Incorporated
• Inventors: ZHANG, Tingkai
• Granted Patent: US 10,473,686 B2
• Time in Patent Office: Days
• 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 2015/0814 for translational movement of the mass, e.g. shuttle type
• 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

An inertia measurement module and three-axis accelerometer, comprising a first pole piece (4) located on a substrate and a mass block (1) suspendingly connected above the substrate via elastic beams (11, 12); the elastic beams (11, 12) includes a first elastic beam (12) and a second elastic beam (11), two ends of the second elastic beams (11) being connected to an anchor point (6) of the substrate, two ends of the first elastic beam (11) being connected to the mass block (1); a center of the first elastic beam (12) and/or the second elastic beam (11) deviates from a center of gravity of the mass block (1); the mass block (1) is further provided with a first movable electrode (9) and a second movable electrode (10) in a Y-axis and an X-axis direction; the movement of one axis in a plane of the inertia measurement module cannot be affected by an eccentric structure feature, such that both X-axis movement and Y-axis movement are linear movements, thus not intensifying an inter-axis coupling, and also not reducing displacement of a mass block on the X-axis and the Y-axis, thus improving capacitance detection precision.

Claims

1-10. -10. (canceled)

11. An inertial measurement module, comprising:

a substrate;

a first pole piece (4), as a lower electrode, located on the substrate;

a mass block (1) suspended above the substrate, an upper electrode for forming a Z-axis detection capacitor with the first pole piece (4) being arranged on the mass block (1); and

elastic beams configured to connect the substrate with the mass block (1), wherein the elastic beams comprise a first elastic beam (12) located in the X-axis direction and a second elastic beam (11) located in the Y-axis direction and cross-connected with the first elastic beam (12);

two ends of the second elastic beam (11) are connected with anchor points (6) on the substrate and two ends of the first elastic beam (12) are connected with the mass block (1), or the two ends of the first elastic beam (12) are connected with the anchor points (6) on the substrate and the two ends of the second elastic beam (11) are connected with the mass block (1);

the center(s) of the first elastic beam and/or the second elastic beam are/is deviated from the gravity center of the mass block (1),

wherein the mass block (1) is further provided with a first movable electrode (9) and a second movable electrode (10) in the Y-axis and X-axis directions, respectively; and

the substrate is provided with a first fixed electrode (2) configured to form a Y-axis detection capacitor with the first movable electrode (9), and a second fixed electrode (3) configured to form an X-axis detection capacitor with the second movable electrode (10).

12. The inertial measurement module of claim 11, wherein there is one first elastic beam (12) located on the center line in the X-axis direction of the mass block (1), and the second elastic beam (11) is deviated from the center line in the Y-axis direction of the mass block (1).

13. The inertial measurement module of claim 11, wherein there are two first elastic beams (12) symmetrically distributed along the center line in the X-axis direction of the mass block (1), and the second elastic beams (11) are deviated from the center line in the Y-axis direction of the mass block (1).

14. A triaxial accelerometer, comprising:

two structurally symmetric inertial measurement modules of claim 12; and

a connecting beam for connecting the mass blocks (1) in the two inertial measurement modules.

15. The triaxial accelerometer of claim 14, wherein the connecting beam comprises transverse beams (7) located in the X-axis direction, and longitudinal beams (8) located in the Y-axis direction;

one end of the longitudinal beam is connected with the corresponding transverse beam (7), and the other end thereof is connected with the side wall of the corresponding mass block (1); and

the longitudinal beams (8) and the second elastic beams (11) are in the same straight line.

16. The triaxial accelerometer of claim 15, further comprising:

reinforcing beams (130) for connecting the two transverse beams (7),

wherein the second elastic beams (11) in the two inertial measurement modules are symmetrically distributed with respect to the reinforcing beams (130).

17. The triaxial accelerometer of claim 16, wherein:

two reinforcing beams (130) are provided parallel to each other, and

the two reinforcing beams (130) and the transverse beams (7) form a rectangular frame.

18. The triaxial accelerometer of claim 17, further comprising a cant beam (131) located in the rectangular frame.

19. A triaxial accelerometer, comprising:

two structurally symmetric inertial measurement modules of claim 11, the first elastic beams (12) thereof being deviated from center lines in the X-axis direction of the mass blocks (1);

a connecting beam for connecting two sides of the mass blocks (1) in the two inertial measurement modules, respectively, the connecting beam comprising transverse beams (7) located in the X-axis direction and longitudinal beams (8) located in the Y-axis direction, one end of the longitudinal beam being connected with the corresponding transverse beam (7), and the other end thereof being connected with the side wall of the corresponding mass block (1); and

reinforcing beams (130) for connecting the two transverse beams (7), wherein the second elastic beams (11) in the two inertial measurement modules are symmetrically distributed with respect to the reinforcing beams (130).

20. The triaxial accelerometer of claim 19, wherein there are two reinforcing beams (130) parallel to each other, and the two reinforcing beams (130) and the transverse beams (7) form a rectangular frame.