Unidirectional ear microphone and method

• US 5,363,444 A
• Filed: 01/18/1994
• Issued: 11/08/1994
• Est. Priority Date: 05/11/1992
• Status: Expired due to Term

• 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): Dwyer, James L.
• Assistant Examiner(s): Chiang, Jack
• Application Number:
  US08/183,625
• Time in Patent Office: 294 Days
• Field of Search: 379/430, 379/433, 381/68.1, 381/68.3, 381/68.6, 381/151, 381/159, 381/183, 381/187, 381/169, 381/186, 381/191, 381/155
• US Class Current: 379/430
• CPC Class Codes: H04M 1/05 specially adapted for use on head, throat or breast
• CPC Class Codes: H04M 1/19 Arrangements of transmitters, receivers, or complete sets to prevent eavesdropping, to attenuate local noise or to prevent undesired transmission; Mouthpieces or receivers specially adapted therefor circuit arrangements for preventing eavesdropping H04M1/68; telephone cabinets E04H1/14
• CPC Class Codes: H04R 1/08 Mouthpieces; Microphones; Attachments therefor
• CPC Class Codes: H04R 1/1016 Earpieces of the intra-aural type
• CPC Class Codes: H04R 1/1075 Mountings of transducers in earphones or headphones
• CPC Class Codes: H04R 1/1083 Reduction of ambient noise active noise reduction per se G10K11/175; protective devices for the ear, e.g. providing acoustic protection A61F11/06
• CPC Class Codes: H04R 1/38 in which sound waves act upon both sides of a diaphragm and incorporating acoustic phase-shifting means, e.g. pressure-gradient microphone
• CPC Class Codes: H04R 2201/107 Monophonic and stereophonic headphones with microphone for two-way hands free communication
• CPC Class Codes: H04R 2499/11 Transducers incorporated or for use in hand-held devices, e.g. mobile phones, PDA's, camera's

Abstract

An ear piece device configured for being supported in the ear and providing a microphone which primarily detects only sounds originated by 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 is contained within a casement which is mechanically and acoustically isolated from vibrations occurring within the housing. Mounting rings formed of acoustical absorbing materials are interposed around the casement and between the housing and casement in a displaced configuration on opposing ends of the casement to result in cancellation of residual vibrations passing to the microphone element from the housing. 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 element which detects only sounds generated within the immediate vicinity of the skull of a user, said ear piece including:

a housing having a first end configured to fit snugly at the ear canal of the user, said housing including an interior surface defining a microphone compartment therein;

a microphone casing disposed within the microphone compartment and having first and second opposing walls, said casing defining a microphone enclosure therein;

a microphone support member for receiving mechanical vibrations disposed within the casing and having first and second opposing ends coupled to the first and second opposing walls of the casing, respectively, such that said support member spans the microphone enclosure and is substantially enclosed therein;

a microphone element coupled to the support member such that the microphone element is substantially enclosed within the microphone casing and is separated from contact with the skull by the housing, said microphone element and said support member being collectively interposed between the first and second opposing walls of the casing;

first and second mounting rings being relatively adjustable with respect to and circumscribing the microphone casing, said rings being positioned between an interior surface of the housing and an exterior surface of the microphone casing to receive mechanical waves from said housing, said rings defining first and second substantially parallel imaginary planes, respectively, said planes pass through the opposing walls of the casings, said rings further being positioned at approximate equal entry distances from and on opposing sides of the microphone element such that the support member and said microphone element reside approximately midway between said parallel planes, said mounting rings thereby enabling cancellation at the microphone element of substantially all mechanical and acoustical waves passing through said rings and into the casing to the microphone element wherein (1) said mechanical waves enter the microphone compartment from the housing and (2) said acoustical waves enter the microphone compartment through air transmission openings from a substantial distance as compared to the relatively near location of the user'"'"'s skull; and

means for coupling signal output from the microphone element to an audio circuit for processing.

2. A device as defined in claim 1, wherein the microphone element and compartment are positioned at a second end of the housing from the first end of the housing which is configured to fit snugly at the ear canal.

3. 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 microphone element being suspended askew to the elongate axis to provide directional orientation with respect to source of proximal sound vibrations to be detected.

4. A device as defined in claim 3, wherein the microphone compartment includes an elongate tubular bore which is oriented askew with respect to an elongate housing axis, said microphone element being positioned at a more interior portion of the tubular bore toward the elongate housing axis, said tubular bore including an opening communicating to the microphone compartment at an interior end of the tubular bore.

5. A device as defined in claim 1, wherein the housing tapers in configuration from the first end which fits snugly at the ear canal to a tubular body of lesser dimension at the microphone compartment at the second end of the housing, said microphone compartment having at least one forward opening positioned at a forward portion of the compartment and at least one distal opening being positioned at a distal portion of the compartment with respect to the ear canal.

6. A device as defined in claim 1, including (i) a first opening between the surrounding environment and the microphone, the first opening is positioned on an upper side and toward one end of the microphone compartment enabling entry of sound waves therein, and (ii) a second opening between the surrounding environment and the microphone, the second opening is positioned on a lower side and toward an opposite end of the compartment from the first opening, said microphone element being positioned therebetween to provide for cancellation of distant sound waves as they reach the microphone element out of phase.

7. A device as defined in claim 1, 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.

8. 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.

9. A device as defined in claim 7, 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, said audio transmission and attendant vibration of the speaker element being isolated from the housing by sound insulation means coupled between the speaker element and the housing to prevent pick up of the transmission through the housing and into the microphone element.

10. A device as defined in claim 9, wherein the isolation means comprises a vibration absorbing 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.

11. A device as defined in claim 10, further including means for isolating from the housing any vibration carried by connecting wires which supply power to the speaker element.

12. A device as defined in claim 7, wherein the microphone compartment comprises a rearward portion of the housing and includes a tubular bore which extends at right angles with respect to the remaining portion of the housing, said tubular bore having a substantially closed interior end and an open distal end, said microphone element being positioned in the interior end of the microphone compartment, said interior end also including a small opening for permitting entry of sound waves from the surrounding environment.

13. A device as defined in claim 1, wherein the respective mounting rings have been empirically positioned along the microphone casing to maximize the degree of noice cancellation at the microphone element.

14. A device as defined in claim 7, further comprising a second housing portion extending at right angles from the 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.

15. A device as defined in claim 7, 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.

16. A device as defined in claim 7, 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.

17. A device as defined in claim 7, further comprising associated communication and transfer circuitry tuned to a common frequency with a 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.

18. A device as defined in claim 7, 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.

19. A device as defined in claim 10, said isolating means comprising a material which selectively limits passage of vibration for frequencies which give rise to feed back between the speaker and microphone elements which are contained within the housing.

20. 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, said speaker end and microphone end being divided by an acoustically insulating wall which encloses the microphone end to form a microphone compartment;

a microphone casing disposed within the microphone compartment and having first and second opposing walls, said casing defining a microphone enclosure therein;

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 absorbing undesirable frequencies that interfere with sensitivity of audio pick up at the microphone end of the housing;

a microphone element contained within the microphone casing and having first and second opposing ends coupled to the first and second opposing walls of the casing, respectively, such that the microphone element spans the microphone enclosure and is substantially enclosed therein so as to be separated from contact with the skull by the housing, said microphone element being interposed between said first and second opposing walls of the casing;

first and second mounting rings comprised of acoustical insulation material, said first and second rings being relatively adjustable with respect to and circumscribing the microphone casing, said rings are positioned between an interior surface of the housing and an exterior surface of the microphone casing to receive mechanical vibrations from said housing, said rings defining first and second substantially parallel imaginary planes, respectively, said planes pass through the opposing walls of the casing, said rings further being positioned at approximate equal entry distances from and on opposing sides of the microphone element such that said microphone element resides approximately midway between said parallel planes, said mounting rings thereby enabling cancellation at the microphone element of substantially all mechanical and acoustical vibrations passing through said rings and into the casing to the microphone element wherein (1) said mechanical vibrations enter the microphone compartment from the housing and (2) said acoustical vibrations enter the microphone compartment through air transmission openings from a substantial distance as compared to the relatively nearby location of the user'"'"'s skull; and

means for coupling signal output from the microphone element to an audio circuit for processing.

21. A device as defined in claim 20, wherein the isolation means comprises a vibrational absorbing 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 frequencies which will be transmitted, to prevent transmission of interfering vibration into the housing from the speaker element.

22. A device as defined in claim 21, wherein the isolation means comprises a material which is tuned to acoustically isolate the housing from the speaker element to prevent feedback.

23. A device as in claim 20, further comprising a sizing ring positioned around the speaker end of the housing for adjusting housing size for snug fit at the ear canal.

24. 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 containing (i) a speaker element and (ii) a casement having first and second opposing walls and containing a microphone element, at an ear canal supported by a user'"'"'s ear cartilage;

b) mechanically and acoustically isolating the speaker element from the housing to limit the amount of sound vibration which is carried into the housing;

c) coupling a first and second end of the microphone element to the opposing walls, respectively, of the casement such that said microphone element is interposed between said opposing walls and substantially enclosed with said casement;

d) positioning first and second mounting rings between an interior surface of the housing and an exterior surface of the casement for receiving mechanical vibrations from the housing, and circumscribing the casement with the first and second rings which are relatively adjustable with respect to the casement, such that said rings surround the opposing walls of said casement and define first and second substantially parallel imaginary planes which pass through the opposing walls and the casement at approximate equal entry distances from and on opposing sides of the microphone element, such that the microphone element resides approximately midway between said planes to thereby mechanically and acoustically isolating the microphone element from the housing to limit the amount of sound vibration which is carried into the microphone element; and

e) concurrently channelling said sound vibration from the housing through the mounting rings and along sound paths having substantially equivalent lengths into opposite sides of the microphone element within the casement such that the sound vibration reaches the microphone element along the opposing sides of the casement at approximately the same time but in opposing phase relationship to result in wave cancellation at the microphone element.