Communication device using bone conduction

• US 20030048915A1
• Filed: 07/09/2002
• Published: 03/13/2003
• Est. Priority Date: 01/27/2000
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: New Transducers Limited (Alphabet Inc.)
• Inventors: Bank, Graham
• Granted Patent: US 6,885,753 B2
• Time in Patent Office: Days
• US Class Current: 381/326
• CPC Class Codes: H04M 1/05 specially adapted for use on head, throat or breast
• CPC Class Codes: H04R 1/028 associated with devices performing functions other than acoustics, e.g. electric candles
• 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 17/00 Piezoelectric transducers; Electrostrictive transducers piezoelectric or electrostrictive elements in general H10N30/00; details of piezoelectric or electrostrictive motors, generators or positioners H10N30/00
• CPC Class Codes: H04R 2460/13 Hearing devices using bone conduction transducers
• CPC Class Codes: H04R 2499/13 Acoustic transducers and sound field adaptation in vehicles
• CPC Class Codes: H04R 7/045 using the distributed mode principle, i.e. whereby the acoustic radiation is emanated from uniformly distributed free bending wave vibration induced in a stiff panel and not from pistonic motion

Abstract

A communication device comprising a microphone, a conduction interface and an electromechanical force transducer mounted to the conduction interface to drive the interface to conduct sound to a user by bone conduction, characterised in that the transducer has an intended operative frequency range and comprises a resonant element having a frequency distribution of modes in the operative frequency range and coupling means for mounting the transducer to the interface.

Claims

1. A communication device, comprising:

a microphone,

a conduction interface,

an electromechanical force transducer mounted to the conduction interface to drive the interface to conduct sound to a user by bone conduction, wherein the transducer has an intended operative frequency range and comprises a resonant element having a frequency distribution of modes in the operative frequency range, and

a coupler for mounting the transducer to the interface.

2. A communication device according to claim 1, wherein the conduction interface is mounted adjacent a user'"'"'s mastoid bone.

3. A communication device according to claim 1, wherein the coupler is attached to the resonant element at a position which is beneficial for coupling modal activity of the resonant element to the interface.

4. A communication device according to claim 1, wherein the parameters of the resonant element are selected to enhance the distribution of modes in the resonant element in the operative frequency range.

5. A communication device according to claim 4, wherein the distribution of modes in the resonant element has a density of modes which is sufficient for the resonant element to provide an effective mean average force which is substantially constant with frequency.

6. A communication device according to claim 4, wherein the modes are distributed substantially even over the intended operative frequency range.

7. A communication device according to claim 2, comprising:

a casing having an extension remote from the microphone, the transducer being mounted in the extension whereby in use the transducer is adjacent a user'"'"'s mastoid bone.

8. A communication device according to claim 1, wherein the resonant element is modal along two substantially normal axes, each axis having an associated fundamental frequency and the ratio of the two associated fundamental frequencies being adjusted for best modal distribution.

9. A communication device according to claim 8, wherein the ratio of the two fundamental frequencies is about 9:

7.

10. A communication device according to claim 1, wherein the transducer comprises a plurality of resonant elements each having a distribution of modes, the modes of the resonant elements being arranged to interleave in the operative frequency range whereby the distribution of modes in the transducer as a whole device is enhanced.

11. A communication device according to claim 1, wherein the resonant element is plate-like.

12. A communication device according to claim 1, wherein the shape of the resonant element is selected from the group consisting of beam-like, trapezoidal, hyperelliptical, generally disc shaped and rectangular.

13. A communication device according to claim 4, wherein the resonant element is plate-like.

14. A communication device according to claim 4, wherein the shape of the resonant element is selected from the group consisting of beam-like, trapezoidal, hyperelliptical, generally disc shaped and rectangular.

15. A communication device according to claim 1, wherein the communication device is selected from the group consisting of a telephone, a hearing aid, eyeglasses, and a headset.