HIGH-PERFORMANCE BENDING ACCELEROMETER

• US 20130247662A1
• Filed: 12/08/2010
• Published: 09/26/2013
• Est. Priority Date: 12/08/2010
• Status: Abandoned Application

• Current Assignee: Microfine Materials Technologies Pte Ltd
• Original Assignee: Microfine Materials Technologies Pte Ltd
• Inventors: Jin, Jing, Teo, Wee Boon Dennis, Xia, Yuexue
• Application Number:
  US13/992,203
• Publication Number:
  US 20130247662A1
• Time in Patent Office: Days
• US Class Current: 73/504.03
• CPC Class Codes: G01P 15/0922 of the bending or flexing mode type

Abstract

An accelerometer comprises an elastic substrate beam having a first end and a second end and having upper and lower surfaces; supports to support the first and second ends of the substrate beam; sensing elements comprising piezoelectric material bonded onto the upper, lower or both the upper and lower surfaces of the substrate beam; and force applying elements for applying forces at two locations between the first and second ends. The substrate beam and the piezoelectric materials operate in a four-point bending configuration. Optionally the first and second ends of the substrate beam are formed by bending the substrate beam to reduce the physical dimensions of the device.

Claims

1. An accelerometer comprising:

an elastic substrate beam having a first end and a second end and having upper and lower surfaces;

supports to support the first and second ends of the substrate beam;

sensing elements comprising piezoelectric material bonded onto the upper, lower, or both the upper and lower surfaces of the substrate beam; and

force applying elements for applying forces at two locations between the first and second ends,

whereby the substrate beam and the piezoelectric materials operate in a four-point bending configuration.

2. The accelerometer of claim 1, wherein:

(a) the first and second ends of the substrate beam are fixed by the supports;

(b) the first and second ends of the substrate beam are simply-supported by the supports;

(c) the first and second ends of the substrate beam are supported by the supports in the way between fixed-end and simply-supported condition;

or

(d) the substrate beam is bent at both ends to reduce the physical dimensions of the device.

6. The accelerometer of claim 1:

(a) wherein two proof masses are positioned across the beam substrate in between the two ends to provide a load to the beam substrate;

(b) the accelerometer of (a), wherein the proof masses are each positioned at an equal distance from either support of the substrate beam;

(c) the accelerometer of (a) or (b), wherein each of the respective proof masses comprises two or more smaller masses.

9. The accelerometer of claim 1, wherein the substrate beam has a plate-like configuration with a beam width equal to or larger than its span.

10. The accelerometer of claim 1, wherein the piezoelectric material comprises piezoelectric single crystals with transverse piezoelectric coefficients in excess of 500 pC/N in absolute value.

11. The accelerometer of claim 1, wherein said sensing elements comprise single crystals with dielectric constants in excess of 1500₀ and wherein ₀ is permittivity of vacuum.

12. The accelerometer of claim 11, wherein the sensing elements comprise at least one of optimally poled PZN-PT or PMN-PT solid-solution single crystals or doped derivatives thereof, said crystals comprising:

Pb(Zn, A₁, A₂, A₃, . . . )_1/3(Nb, C₁, C₂, C₃, . . . )_2/3O₃-xPbTiO₃ with 0.045≦

x≦

0.09 and Pb(Mg, B₁, B₂, B₃, . . . )_1/3(Nb, C₁, C₂, C₃, . . . )_2/3O₃-yPbTiO₃ with 0.26≦

y≦

0.33

where

A₁, A₂, A₃, . . . includes at least one of Mg²⁺, Ni²⁺, Fe²⁺, Co²⁺, Yb²⁺, Sc³⁺, and In³⁺ and totals up to one-third of a mole fraction of Zn²⁺;

B₁, B₂, B₃, . . . includes at least one of Zn²⁺, Ni²⁺, Fe²⁺, Co²⁺, Yb²⁺, Sc³⁺, and In³⁺ and totals up to one-third of a mole fraction of Mg²⁺;

C₁, C₂, C₃, . . . includes at least one of Ta⁵⁺, W⁶⁺, and Mo⁶⁺ and totals up to one-quarter of a mole fraction of Nb⁵⁺.

13. The accelerometer of claim 11, wherein the sensing elements comprise at least one of optimally poled binary, ternary, or higher-order solid solution single crystals of suitable cuts and dimensions of the following components:

Pb(Zn_1/3Nb_2/3)O₃, Pb(Mg_1/3Nb_2/3)O₃, Pb(In_1/2Nb_1/2)O₃, Pb(Sc_1/2Nb_1/2)O₃, Pb(Fe_1/2Nb_1/2)O₃, Pb(Mn_1/2Nb_1/2)O₃, PbZrO₃ and PbTiO₃.

14. The accelerometer of claim 1, wherein the sensing elements comprise at least one of the poled PZT ceramics and doped derivatives thereof.

15. The accelerometer of claim 1, wherein the respective sensing elements are connected electrically in at least one of parallel, serial, or a combination thereof.

16. The accelerometer of claim 1, further comprising at least one mount structure.

17. The accelerometer of claim 1, further comprising a housing.

18. A multi-axial accelerometer comprising at least one accelerometer of claim 1.

19. A linear motion sensor comprising at least one accelerometer of claim 1.

20. A multi-axis motion sensor comprising at least one accelerometer of claim 1.

21. An angular rate sensor comprising at least one accelerometer of claim 1.

22. A multi-axis angular rate sensor comprising at least one accelerometer of claim 1.

23. A rotation motion sensor comprising at least one accelerometer of claim 1.

24. A linear-cum-rotation sensor comprising at least one accelerometer of claim 1.

25. A multi-axis linear-cum-rotation sensor comprising at least one accelerometer of claim 1.

3-5. -5. (canceled)

7-8. -8. (canceled)