Transducer with Integrated Sensor

• US 20120177211A1
• Filed: 01/06/2011
• Published: 07/12/2012
• Est. Priority Date: 01/06/2011
• Status: Active Grant

• Current Assignee: Bose Corporation
• Original Assignee: Bose Corporation
• Inventors: Yamkovoy, Paul G., Wendell, John H.
• Granted Patent: US 9,241,227 B2
• Time in Patent Office: Days
• US Class Current: 381/59
• CPC Class Codes: G01D 5/2417 by varying separation
• CPC Class Codes: H04R 29/003 of the moving-coil type
• CPC Class Codes: H04R 3/002 Damping circuit arrangements for transducers, e.g. motional feedback circuits

Abstract

An electroacoustic transducer includes a housing and a moving portion adapted to move relative to the housing. The moving portion has a first surface and includes a first electrode. A second electrode on a first surface of the housing is located proximate to a first region of the first electrode, and a third electrode on the first surface of the housing is located proximate to a second region of the first electrode. A capacitance between the first and second electrodes and a capacitance between the first and third electrodes vary similarly with displacement of the moving portion relative to the housing. An impedance buffer is coupled to the second electrode and the third electrode.

Claims

1. An electroacoustic transducer comprising:

a housing;

a moving portion located proximate to the housing, adapted to move relative to the housing;

a displacement sensor comprising;

a first electrode adhered to the moving portion,

a second electrode on a first surface of the housing located proximate to a first region of the first electrode, and

a third electrode on the first surface of the housing located proximate to a second region of the first electrode,

wherein a first capacitance between the first electrode and the second electrode and a second capacitance between the first electrode and the third electrode each vary similarly with a displacement of the moving portion relative to the housing; and

an impedance buffer coupled to the second electrode and the third electrode.

2. The electroacoustic transducer of claim 1 wherein the change in distance between a first surface of the housing and the first surface of the moving portion resulting from movement of the moving portion is substantially uniform over the area of the second and third electrodes.

7. The electroacoustic transducer of claim 1 wherein the moving portion is metal and comprises the first electrode.

8. The electroacoustic transducer of claim 1 wherein the moving portion comprises a diaphragm.

12. The electroacoustic transducer of claim 1 wherein the first surface of the housing is a surface of a block of conductive material, and the second and third electrodes comprise portions of the block that are electrically insulated from each other.

13. The electroacoustic transducer of claim 1 wherein the first surface of the housing is a surface of a block of non-conductive material, and the second and third electrodes comprise layers of metal adhered to the block of non-conductive material.

15. The electroacoustic transducer of claim 1 wherein the housing comprises a basket.

16. The electroacoustic transducer of claim 1 wherein the housing comprises a pole piece.

17. The electroacoustic transducer of claim 1 wherein the moving portion comprises a voice coil mechanically coupled to a diaphragm.

18. The electroacoustic transducer of claim 1 wherein the moving portion comprises a magnet mechanically coupled to a diaphragm.

19. The electroacoustic transducer of claim 1 wherein the layer of metal of the first electrode comprises a coating on a non-conductive substrate.

3. -6. (canceled)

9. -11. (canceled)

14. (canceled)

20. An electroacoustic transducer comprising:

a housing;

a diaphragm located proximate to the housing and adapted to move relative to the housing;

a displacement sensor comprising;

a first electrode adhered to the housing,

a second electrode on a first surface of the diaphragm located proximate to a first region of the first electrode, and

a third electrode on the first surface of the diaphragm located proximate to a second region of the first electrode,

wherein a first capacitance between the first electrode and the second electrode and a second capacitance between the first electrode and the third electrode each vary similarly with a displacement of the diaphragm relative to the housing; and

an impedance buffer coupled to the second electrode and the third electrode at non-moving points at a periphery of the diaphragm.

21. The electroacoustic transducer of claim 20 wherein:

the second and third electrode each comprise a layer of metal adhered to a top surface of the diaphragm facing away from the first surface of the housing;

the diaphragm is attached to the housing by a ring surrounding a periphery of the diaphragm; and

electrical connections to the second and third electrodes are made via the ring at the periphery of the diaphragm.

22. The electroacoustic transducer of claim 20 wherein:

the second and third electrode each comprise a layer of metal adhered to a bottom surface of the diaphragm facing towards the first surface of the housing; and

electrical connections to the second and third electrodes are made via the housing where the housing contacts an outer periphery of the diaphragm.

23. (canceled)