Bone conductive ear microphone and method

• US 5,280,524 A
• Filed: 05/11/1992
• Issued: 01/18/1994
• Est. Priority Date: 05/11/1992
• Status: Expired due to Fees

• Current Assignee: Jabra Corporation (GN Store Nord A/S)
• Original Assignee: Jabra Corporation (GN Store Nord A/S)
• Inventors: Norris, Elwood G.
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US07/881,425
• Time in Patent Office: 617 Days
• Field of Search: 379/430, 379/78, 379/85, 379/444, 379/388, 379/420, 379/387, 381/163, 381/169, 381/187
• US Class Current: 379/388.02
• CPC Class Codes: H04M 1/05 specially adapted for use on head, throat or breast
• CPC Class Codes: H04R 1/46 Special adaptations for use as contact microphones, e.g. on musical instrument, on stethoscope throat mountings H04R1/14
• CPC Class Codes: H04R 2460/13 Hearing devices using bone conduction transducers

Abstract

An ear piece device configured for being supported in the ear and providing a microphone which is sensitive only to sounds conducted within the skull of the user is contained within a housing which is configured at one end to fit snugly at the ear canal of the user, but not to extend within the ear canal. A microphone element is coupled within the housing in a position such that the microphone element is separated from contact with the skull of the user by the housing. This microphone element includes an inertial platform which has sufficient inertial mass to substantially resist movement associated with the housing by reason of audio vibration and which is cantilevered at one end within the housing and includes signal means for generating a signal representing vibrations transferred into the housing in the form of audio vibrations from the user. This signal is supplied to an audio circuit for processing and reproduction of the user'"'"'s voice. A speaker element may be included within the ear device and can be decoupled acoustically so as to avoid feedback. This system can operate with full duplex and enable hands free communication and direct voice command by user through computer modems, telephone networks and other communication systems.

Claims

1. An ear piece device configured for being supported at the ear and providing a microphone which is sensitive only to sounds conducted within the skull of the user, said ear piece including:

a housing which is configured at one end to fit snugly at the ear canal of the user but not extend into the ear canal, and includes means for passing sound waves into the housing, said housing being constructed of material which is sound conductive;

a microphone element coupled within the housing;

said microphone element including an inertial platform having sufficient inertial means to substantially resist movement associated with the housing by reason of audio vibration and which is cantilevered at one end within the housing and includes signal means for generating a signal representing vibrations transferred into the platform associated with the audio vibrations in the housing, wherein the inertial platform is suspended inside the housing but in a position which is not placed within the ear canal of the user during operation;

said signal means being coupled to electrical circuitry for converting relative movement of the inertial platform with respect to the housing into audio signal suitable for processing in an audio circuit.

2. A device as defined in claim 1, wherein the inertial platform is positioned at an opposing end of the housing from that portion of the housing which is configured to fit snugly at the ear canal.

3. A device as defined in claim 2, further comprising a speaker element positioned at an end of the housing adjacent the ear canal, said microphone element being positioned at the opposing end of the housing.

4. A device as defined in claim 3, wherein the housing includes an opening oriented toward the ear canal when in position, said opening including the speaker element being positioned thereat for direct exposure to the ear canal to enable the user to receive audio transmissions as well as send audio signal through the microphone element, said audio transmission and attendant vibration of the speaker element being isolated from the housing by sound insulation means to prevent pick up of the transmission through the housing and into the microphone element.

5. A device as defined in claim 4, wherein the isolation means comprises a nonvibrational ring extending around the speaker element and being coupled between the housing and perimeter of the speaker element to prevent transmission of vibration into the housing.

6. A device as defined in claim 5, further including means for isolating from the housing any vibration carried by connecting wires which supply power to the speaker element.

7. A device as defined in claim 5, said isolating means comprising a material which selectively limits passage of vibration for frequencies which could give rise to feed back between the speaker and microphone elements which are contained within the housing.

8. A device as defined in claim 3, wherein the housing portion which contains the speaker element includes a truncated conical section which tapers to a juncture with an acoustical lens configured to receive amplified speech vibrational energy applied to the housing from the skull of the user.

9. A device as defined in claim 8, wherein the acoustical lens comprises a small structural element having a cross-section configured as an I-beam, said housing being coupled to a face at one side of the 1-beam and said inertial platform being extended from the face at the other side of the I-beam, said I-beam thereby being operable to focus vibrations collected from the housing into the small I-beam structure for maximum relative movement with respect to the inertial platform.

10. A device as defined in claim 9, wherein the housing includes a rearward portion which extends at right angles with respect to the remaining portion of the housing, said rearward portion containing the inertial platform extending from the acoustical lens.

11. A device as defined in claim 10, further comprising a second housing portion extending at right angles from the remaining housing, said second housing portion comprising a conduit for carrying associated wiring from the microphone and speaker elements to an exterior portion of the device.

12. A device as defined in claim 3, further comprising a radio frequency transmitter/receiver unit coupled to the microphone element and speaker element respectively, thereby enabling the use of the ear piece device as part of a wireless system of communication.

13. A device as defined in claim 12, further comprising associated communication and transfer circuitry tuned to a common frequency with the transmitter/receiver unit, thereby enabling use of the ear piece device as part of a microcell communication system, said ear piece device providing direct communication into respective microcell communications satellite receiving and transmitting stations.

14. A device as defined in claim 3, further comprising telephone control circuitry coupled to the speaker element and microphone element, said telephone control circuitry providing access for the speaker element and microphone element as part of a telephone system which provides hands-free use based on both speaking and listening functions being provided through the user'"'"'s ear.

15. A device as defined in claim 3, further including connecting means for coupling the microphone element to a modem associated with a computer, said connecting means enabling direct audio transmission into the modem without outside audio signal other than the voice of the user.

16. A device as defined in claim 3, further comprising a sizing ring coupled to the housing, including means for modifying the diameter of the housing which is snugly fit at the ear canal.

17. A device as defined in claim 1, wherein the housing is configured with a tapering body to provide an acoustical lens which amplifies the sound vibrations received from the skull at a convergence of the housing.

18. A device as claimed in claim 17, wherein the acoustical lens includes a small structural element having a cross-section configured as an I-beam, said housing convergence being coupled to a face at one side of the I-beam and said inertial platform being extended from the face at the other side of the I-beam, said I-beam thereby being operable to focus vibrations collected from the housing into the small I-beam structure for maximum relative movement with respect to the inertial platform.

19. A device as defined in claim 1, wherein the inertial platform comprises an elongate piezoelectric crystal which is coupled at an end to the housing, said crystal being configured to enable displacement without substantial movement of the piezoelectric crystal, thereby imposing stress at the crystal to generate electrical output for development of the signal for audio processing. 1

20. A device as defined in claim 1, wherein the housing includes an elongate axis which is oriented along the portion of the housing which is supported at the ear canal, said axis being directionally oriented toward the ear canal when the housing is in position for use;

said inertial platform being suspended at right angles to the elongate axis to develop relative movement in response to sound vibrations transmitted into the housing along the elongate axis.

21. A device as in claim 1, further comprising a sizing ring positioned around the speaker end of the housing for adjusting housing size for snug fit at the ear canal.

22. An ear piece device for use in a communication system, said device comprising:

a housing having a speaker end and a microphone end, said speaker end being configured for a snug fit at the ear canal of a user without including structure which substantially enters the ear canal during operation;

a speaker element mounted with sound projection oriented toward the user'"'"'s ear canal and including isolation means coupled between the speaker element and the housing for selectively isolating undesirable frequencies that might interfere with sensitivity of audio pick up at the microphone end of the housing;

a microphone element mounted at the microphone end of the housing, said microphone element being coupled to an acoustical lens which is attached between the speaker end and microphone end of the housing;

said acoustical lens comprising a small vibration-sensitive element which is coupled between the speaker end and the microphone end of the housing such that audio vibrations received from the skull of the user are transmitted through the housing and into the acoustical lens;

the other end of the acoustical lens including an attached inertial platform which includes means for converting relative physical vibrations actuated by sound waves received from the user'"'"'s skull into an electric signal capable of audio processing for reproduction.

23. A device as defined in claim 22, wherein the isolation means comprises a nonvibrational ring extending around the speaker element and being coupled between the housing and perimeter of the speaker element, said ring being formed of material which is selective as to a range of frequencies which will be decoupled as compared to those which will be transmitted, to prevent transmission of interfering vibration into the housing.

24. A device as defined in claim 23, wherein the isolation means comprises a material which is tuned to acoustically isolate the housing from the speaker element to prevent feedback.

25. A device as defined in claim 24, wherein the material includes silicone.

26. A device as defined in claim 22, wherein the inertial platform comprises a piezoelectric crystal which is capable of detecting differences in stress arising because of vibration of the housing as a consequence of voice vibrations conducted through the user'"'"'s skull.

27. A device as defined in claim 22, wherein the acoustical lens comprises a small structural element having a cross-section configured as an I-beam, said housing being coupled to a face at one side of the I-beam and said inertial platform being extended from the face at the other side of the I-beam, said I-beam thereby being operable to focus vibrations collected from the housing into the small I-beam structure for maximum relative movement with respect to the inertial platform.

28. A device as in claim 22, further comprising a sizing ring positioned around the speaker end of the housing for adjusting housing size for snug fit at the ear canal.

29. A method for isolating an individual'"'"'s speech for reproduction from an environment of background noise which is not be detected, said method comprising the steps of:

a) positioning a housing device in contact with a portion of the individual'"'"'s skull but outside an ear canal such that vibrations arising within the skull from voice communications of the individual are transmitted into the housing;

b) gathering sound vibrations from the skull into the housing;

c) suspending a cantilevered inertial platform as part of a microphone element inside the housing but in a position which is not placed substantially within the ear canal of the user during operation;

d) detecting the sound vibrations within the housing by measuring movement with respect to the inertial platform contained within and cantilevered from the housing;

e) producing an electric signal corresponding to the detected sound vibrations with respect to the inertial platform; and

f) converting the electric signal to audio signal.

30. A method as defined in claim 29, further comprising the steps suspending one end of an elongate piezoelectric crystal within the housing as the inertial platform and producing the electric signal based on voltage generated by the crystal in response to changes in stress applied to the crystal by reason of vibrational movement of the housing.

31. A method as defined in claim 29, further comprising the steps of coupling a speaker element at one end of the housing next to the ear canal and acoustically isolating the speaker element from the attached housing by positioning an intermediate vibrationally nonconductive barrier operable over a selective range of sound vibration which is to be precluded from transmission to the housing. PG,42

32. An ear piece device configured for being supported at the ear and providing a microphone which is sensitive only to sounds conducted within the skull of the user, said ear piece including:

a housing which is configured at one end to fit snugly at the ear canal of the user but not extend substantially into the ear canal, and includes means for passing sound waves into the housing, said housing being constructed of material which is sound conductive;

a microphone element coupled within the housing, said microphone element including a support arm and a relatively larger inertial platform suspended at one end of the support arm, said inertial platform having sufficient inertial mass to substantially resist movement associated with the housing by reason of audio vibration, said support arm being cantilevered at a remaining end within the housing and including signal means for generating a signal representing vibrations transferred into the platform associated with the audio vibrations in the housing;

said signal means being coupled to electrical circuitry for converting relative movement of the inertial platform with respect to the housing into audio signal suitable for processing in an audio circuit.

33. A device as defined in claim 32, wherein the inertial platform is suspended inside the housing but in a position which is not placed within the ear canal of the user during operation.

34. A device as defined in claim 33, wherein the inertial platform is positioned at an opposing end of the housing from that portion of the housing which is configured to fit snugly at the ear canal.

35. A device as defined in claim 32, further comprising a speaker element positioned at an end of the housing adjacent the ear canal, said microphone element being positioned at the remaining end of the housing.

36. A device as defined in claim 35, wherein the housing portion which contains the speaker element includes a truncated conical section which tapers to a juncture with an acoustical lens configured to receive amplified speech vibrational energy applied to the housing from the skull of the user.

37. A device as defined in claim 32, wherein the inertial platform comprises an elongate piezoelectric crystal which is coupled at an end to the housing, said crystal being configured to enable displacement without substantial movement of the piezoelectric crystal, thereby imposing stress at the crystal to generate electrical output for development of the signal for audio processing.

38. A device as defined in claim 32, wherein the housing is configured with a tapering body to provide an acoustical lens which amplifies the sound vibrations received from the skull at a convergence of the housing.