Inertial sensor

• US 9,121,864 B2
• Filed: 10/18/2012
• Issued: 09/01/2015
• Est. Priority Date: 11/18/2011
• Status: Active Grant

• Current Assignee: Samsung Electro-Mechanics Co., Ltd. (Samsung Group)
• Original Assignee: Samsung Electro-Mechanics Co., Ltd. (Samsung Group)
• Inventors: Kim, Jong Woon, Jeung, Won Kyu
• Primary Examiner(s): Williams, Hezron E
• Assistant Examiner(s): Shabman, Mark A
• Application Number:
  US13/655,109
• Publication Number:
  US 20130125652A1
• Time in Patent Office: 1,048 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: G01C 19/56 Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces
• CPC Class Codes: G01P 15/09 by piezoelectric pick-up
• CPC Class Codes: G01P 2015/084 the mass being suspended at more than one of its sides, e.g. membrane-type suspension, so as to permit multi-axis movement of the mass

Abstract

Disclosed herein is an inertial sensor. An inertial sensor according to preferred embodiments of the present invention is configured to include a membrane, a plurality of first electrodes patterned on the membrane, a plurality of piezoelectric elements patterned on the first electrodes, and a second electrode integrally formed to cover the piezoelectric elements. By the configuration, the piezoelectric element is encapsulated with the second electrode that is integrally formed to prevent water or humidity from being permeated into the piezoelectric element, thereby preventing physical properties of the piezoelectric element from being changed or preventing the piezoelectric element from being delaminated.

Claims

1. An inertial sensor, comprising:

a membrane;

a plurality of first electrodes patterned on the membrane;

a plurality of piezoelectric elements patterned on the first electrodes;

a second electrode integrally formed to cover the piezoelectric elements; and

second insulators formed at the outer surface of the piezoelectric element formed at the outside among the patterned piezoelectric elements,

wherein the second electrode is formed to cover the piezoelectric elements and the second insulators.

2. The inertial sensor as set forth in claim 1, further comprising:

insulators formed between adjacent piezoelectric elements among the patterned piezoelectric elements;

wherein the second electrode is formed to cover the piezoelectric elements and the insulator.

3. The inertial sensor as set forth in claim 1, wherein the piezoelectric element and the first electrode are patterned to be identical to each other.

4. The inertial sensor as set forth in claim 1, wherein the piezoelectric elements are made of lead zirconate titanate (PZT), barium titanate (BaTiO₃), lead titanate (PbTiO₃), lithium niobate (LiNbO₃), or quartz (SiO₂).

5. The inertial sensor as set forth in claim 1, wherein the piezoelectric elements is patterned by etching.

6. The inertial sensor as set forth in claim 5, wherein a transverse sectional area of the piezoelectric element is expanded toward the membrane.

7. The inertial sensor as set forth in claim 1, further comprising:

a mass body formed on a bottom portion of a central portion of the membrane; and

a post formed on a bottom portion of an edge of the membrane.

8. The inertial sensor as set forth in claim 1, further comprising:

an insulating layer formed between the membrane and the first electrode.

9. The inertial sensor as set forth in claim 8, wherein the insulating layer is made of silicon oxide (SiO₂).

10. An inertial sensor, comprising:

a membrane;

a plurality of first electrodes patterned on the membrane;

a piezoelectric element integrally formed on the first electrodes;

a second electrode integrally formed to cover the piezoelectric element; and

second insulators formed at the outside of the patterned piezoelectric element,

wherein the second electrode is formed to cover the piezoelectric elements and the second insulator.

11. The inertial sensor as set forth in claim 10, wherein the piezoelectric element is made of lead zirconate titanate (PZT), barium titanate (BaTiO₃), lead titanate (PbTiO₃), lithium niobate (LiNbO₃), or quartz (SiO₂).

12. The inertial sensor as set forth in claim 10, further comprising:

a mass body formed on a bottom portion of a central portion of the membrane; and

a post formed on a bottom portion of an edge of the membrane.

13. The inertial sensor as set forth in claim 10, further comprising:

an insulating layer formed between the membrane and the first electrode.

14. The inertial sensor as set forth in claim 13, wherein the insulating layer is made of silicon oxide (SiO₂).