Implantable and external hearing system having a floating mass transducer

• US 20010003788A1
• Filed: 11/30/2000
• Published: 06/14/2001
• Est. Priority Date: 07/01/1993
• Status: Abandoned Application

• Current Assignee: Vibrant Med-El Hearing Technology GmbH
• Original Assignee: Vibrant Med-El Hearing Technology GmbH
• Inventors: Culp, James M., Dietz, Tim, Salisbury, John D., Ball, Geoffrey R., Mar, Craig
• Application Number:
  US09/728,765
• Publication Number:
  US 20010003788A1
• Time in Patent Office: Days
• US Class Current: 600/25
• CPC Class Codes: H04R 11/02 Loudspeakers
• CPC Class Codes: H04R 25/606 acting directly on the eardrum, the ossicles or the skull, e.g. mastoid, tooth, maxillary or mandibular bone, or mechanically stimulating the cochlea, e.g. at the oval window

Abstract

A floating mass transducer for improving hearing in a hearing impaired person is provided. The floating mass transducer (100) may be implanted or mounted externally for producing-vibrations in a vibratory structure of an ear. In an exemplary embodiment, the floating mass transducer comprises a magnet assembly (12) and a coil (14) secured inside a housing (10) which is fixed to an ossicle of a middle ear. The coil is more rigidly secured to the housing than the magnet. The magnet assembly and coil are configured such that conducting alternating electrical current through the coil results in vibration of the magnet assembly and coil relative to one another. The vibration is caused by the interaction of the magnetic fields of the magnet assembly and coil. Because the coil is more rigidly secured to the housing than the magnet assembly, the vibrations of the coil cause the housing to vibrate. The vibrations of the housing are conducted to the oval window of the ear via the ossicles. In alternate embodiments, the floating mass transducer produces vibrations using piezoelectric materials.

Claims

1. An apparatus for improving hearing, comprising:

a housing mountable on a vibratory structure of an ear;

a mass mechanically coupled to the housing, wherein the mass vibrates in direct response to an externally generated electrical signal; and

whereby vibration of the mass causes inertial vibration of the housing in order to stimulate the vibratory structure of the ear.

2. The apparatus of

claim 1

, wherein the mass includes a magnet which generates a first magnetic field.

3. The apparatus of

claim 2

, wherein the magnet is a permanent magnet or electromagnet.

4. The apparatus of

claim 2

, further comprising:

a coil disposed within the housing; and

leads connected to the coil that deliver the signal to the coil, the signal being an alternating current which causes the coil to generate a second magnetic field;

wherein the first magnetic field interacts with the second magnetic field to cause the magnet to vibrate.

5. The apparatus of

claim 2

, further comprising:

a first coil disposed within the housing on a first side of the magnet;

a second coil disposed within the housing on a second side of the magnet; and

leads connected to the first and second coils that deliver the signal to the coils, the signal being an alternating current which causes the first coil to generate a second magnetic field and the second coil to generate a third magnetic field;

wherein the first magnetic field interacts with the second and third magnetic fields to cause the magnet to vibrate.

6. The apparatus of

claim 1

, wherein the mass includes a coil and the apparatus further comprises leads connected to the coil that deliver the signal to the coil, the signal being an alternating current which causes the coil to generate a first magnetic field.

7. The apparatus of

claim 6

, wherein the housing includes a flexible diaphragm, the coil being coupled to the flexible diaphragm.

8. The apparatus of

claim 6

, further comprising a magnet disposed within the housing which generates a second magnetic field and wherein the first magnetic field interacts with the second magnetic field to cause the coil to vibrate.

9. The apparatus of

claim 8

, wherein the magnet is a permanent magnet or electromagnet.

10. The apparatus of

claim 1

, wherein the mass includes a piezoelectric assembly and the apparatus further comprises leads connected to the piezoelectric assembly that deliver the signal to the piezoelectric assembly, the signal being an alternating current which causes the piezoelectric assembly to vibrate.

11. The apparatus of

claim 10

, wherein the piezoelectric assembly is disposed within the housing.

12. The apparatus of

claim 10

, wherein the piezoelectric assembly comprises:

a piezoelectric material having first and second ends, the first end being coupled to the housing; and

a weight coupled to the second end of the piezoelectric material.

13. The apparatus of

claim 12

, wherein the piezoelectric material includes a piezoelectric bimorph.

14. The apparatus of

claim 12

, wherein the piezoelectric material includes a plurality of piezoelectric strips having a same polarity, each of the piezoelectric strips having a first end coupled to the housing and a second end coupled to the weight.

15. The apparatus of

claim 12

, wherein the piezoelectric material includes a stack of piezoelectric strips having a same polarity, the stack having a first piezoelectric strip coupled to the housing and a second piezoelectric strip coupled to the weight.

16. The apparatus of

claim 10

, wherein the housing includes a flexible diaphragm, the piezoelectric assembly being coupled to the flexible diaphragm.

17. The apparatus of

claim 1

, wherein the housing is mountable on the vibratory structure by a mounting mechanism, wherein the mounting mechanism is a clip, glue, adhesive, velcro, suture, screw, or spring.

18. The apparatus of

claim 1

, wherein the housing includes a hole passing therethrough and an ossicle is positioned in the hole such that the housing encircles the ossicle.

19. The apparatus of

claim 1

, further comprising an ossicular prosthesis coupled to the housing and positioned between a tympanic membrane and an ossicle of the middle ear.

20. The apparatus of

claim 1

, further comprising an ossicular prosthesis coupled to the housing and positioned between two ossicles of the middle ear.

21. The apparatus of

claim 1

, further comprising an ossicular prosthesis coupled to the housing and positioned between an ossicle and an oval window of the middle ear.

22. The apparatus of

claim 1

, further comprising an ossicular prosthesis coupled to the housing and positioned between a tympanic membrane and an oval window of the middle ear.

23. The apparatus of

claim 1

, further comprising:

a pickup coil that receives the signal; and

leads coupled to the pickup coil and the mass, the signal transmitted from the pickup coil to the mass via the leads.

24. The apparatus of

claim 23

, wherein the apparatus is placed in an ear canal such that the housing is in contact with a tympanic membrane.

25. The apparatus of

claim 23

, further comprising a demodulator chip coupled to the leads.

26. The apparatus of

claim 1

, wherein the vibratory structure is a tympanic membrane, ossicle, oval window, round window, or cochlea.

27. A method of improving hearing, comprising the steps of:

mounting a housing on a vibratory structure of the ear, wherein the housing is mechanically coupled to an inertial mass which vibrates in response to an externally generated electrical signal; and

connecting the inertial mass to an external microphone which produces the electrical signal in response to ambient sound.

28. The method of

claim 27

, wherein the housing is mounted on the vibratory structure by a mounting mechanism,

wherein the mounting mechanism is a clip, glue, adhesive, velcro, suture, screw, or spring.

29. The method of

claim 27

, wherein the mounting step includes the steps of:

connecting the housing to an ossicular prosthesis; and

positioning the ossicular prosthesis between a tympanic membrane and an ossicle of a middle ear.

30. The method of

claim 27

, wherein the mounting step includes the steps of:

connecting the housing to an ossicular prosthesis; and

positioning the ossicular prosthesis between two ossicles of a middle ear.

31. The method of

claim 27

, wherein the mounting step includes the steps of:

connecting the housing to an ossicular prosthesis; and

positioning the ossicular prosthesis between an ossicle and an oval window of a middle ear.

32. The method of

claim 27

, wherein the mounting step includes the steps of:

connecting the housing to an ossicular prosthesis; and

positioning the ossicular prosthesis between a tympanic membrane and an oval window of a middle ear.

33. An apparatus for improving hearing, comprising:

a housing adapted to generate mechanical vibrations of a vibratory structure of an ear upon movement of the housing; and

a mass coupled to the housing such that the mass is capable of being moved relative to the housing, the mass moving relative to the housing in response to an external signal;

whereby the signal causes the mass to move relative to the housing resulting in movement of the housing and the vibratory structure.

34. The apparatus of

claim 33

, wherein the mass includes a magnet which generates a first magnetic field.

35. The apparatus of

claim 34

, further comprising:

a coil disposed within the housing; and

leads connected to the coil that deliver the signal to the coil, the signal being an alternating current which causes the coil to generate a second magnetic field;

wherein the first magnetic field interacts with the second magnetic field to cause the magnet to move relative to the housing.

36. The apparatus of

claim 34

, further comprising:

a first coil disposed within the housing on a first side of the magnet;

a second coil disposed within the housing on a second side of the magnet; and

leads connected to the first and second coils that deliver the signal to the coils, the signal being an alternating current which causes the first coil to generate a second magnetic field and the second coil to generate a third magnetic field;

wherein the first magnetic field interacts with the second and third magnetic fields to cause the magnet to move relative to the housing.

37. The apparatus of

claim 33

, wherein the mass includes a coil and the apparatus further comprises leads connected to the coil that deliver the signal to the coil, the signal being an alternating current which causes the coil to generate a first magnetic field.

38. The apparatus of

claim 37

, wherein the housing includes a flexible diaphragm, the coil being coupled to the flexible diaphragm.

39. The apparatus of

claim 37

, further comprising a magnet disposed within the housing which generates a second magnetic field and wherein the first magnetic field interacts with the second magnetic field to cause the magnet to move relative to the housing.

40. The apparatus of

claim 33

, wherein the mass includes a piezoelectric assembly and the apparatus further comprises leads connected to the piezoelectric assembly that deliver the signal to the piezoelectric assembly, the signal being an alternating current which causes the piezoelectric assembly to move relative to the housing.

41. The apparatus of

claim 40

, wherein the piezoelectric assembly comprises:

a piezoelectric material having first and second ends, the first end being coupled to the housing; and

a weight coupled to the second end of the piezoelectric material.

42. The apparatus of

claim 41

, wherein the piezoelectric material includes a piezoelectric bimorph.

43. The apparatus of

claim 41

, wherein the piezoelectric material includes a plurality of piezoelectric strips having a same polarity, each of the piezoelectric strips having a first end coupled to the housing and a second end coupled to the weight.

44. The apparatus of

claim 41

, wherein the piezoelectric material includes a stack of piezoelectric strips having a same polarity, the stack having a first piezoelectric strip coupled to the housing and a second piezoelectric strip coupled to the weight.

45. The apparatus of

claim 40

, wherein the housing includes a flexible diaphragm, the piezoelectric assembly being coupled to the flexible diaphragm.

46. The apparatus of

claim 33

, wherein the vibratory structure is a tympanic membrane, ossicle, oval window, round window, or cochlea.

47. A method of improving hearing, comprising the steps of:

vibrating a mass in direct response to an electrical signal corresponding to ambient sound; and

vibrating a housing mechanically coupled to the mass, wherein vibration of the housing is caused by vibration of the mass and the housing is coupled to a vibratory structure of an ear.

48. The method of

claim 47

, further comprising the step of generating the signal in response to ambient sound.

49. An improved transducer for producing mechanical vibrations in a vibratory structure of an ear having a magnet and a coil, the magnet vibrating relative to the coil in response to an alternating current through the coil, wherein the improvement comprises a housing mountable to the vibratory structure having the magnet and coil disposed therein, the magnet being capable of moving more freely within the housing than the coil such that vibrations of the magnet cause the housing and vibratory structure to vibrate.