Microphone placement in open ear hearing assistance devices

Patent metadata

Field	Value
Publication number	US-12342121-B2
Application number	US-201916534588-A
Country	US
Kind code	B2
Filing date	Aug 7, 2019
Priority date	Aug 7, 2019
Publication date	Jun 24, 2025
Grant date	Jun 24, 2025

Abstract

A head-worn acoustic device includes at least one acoustic transducer disposed such that, in a head-worn state, the transducer is in an open-ear configuration in which an ear canal of a user of the head-worn acoustic device is unobstructed. The acoustic device also includes at least one microphone configured to capture audio that is processed and played back through the transducer, and an amplifier circuit configured to process signals representing the audio captured using the microphone and generate driver signals for the transducer. The transducer and the microphone are disposed on the head-worn acoustic device such that, in the head-worn state, a lobe of a radiation pattern of the at least one acoustic transducer is directed towards the ear canal of the user, and the at least one microphone is positioned in an acoustic null in a radiation pattern of the at least one acoustic transducer.

First claim

What is claimed is:

1. A head-worn acoustic device comprising:
at least one acoustic transducer disposed such that, in a head-worn state, the at least one acoustic transducer is in an open-ear configuration in which an ear canal of a user of the head-worn acoustic device is unobstructed, and wherein the acoustic transducer is disposed within an arm of an eyeglass frame and configured (i) to radiate acoustic waves originating from a first side of the acoustic transducer through a first acoustic channel defined within the arm and (ii) to radiate acoustic waves originating from a second side of the acoustic transducer through a second acoustic channel defined within the arm;
at least two microphones configured to capture audio that is processed and played back through the at least one acoustic transducer;
an active noise reduction (ANR) circuit configured to operate on input from one or more microphones of the at least two microphones to preferentially reduce effects of (i) components of the audio captured using the at least two microphones from a first direction as compared to (ii) components of the audio captured using the at least two microphones from a second direction, wherein the ANR circuit is configured to reduce effects of audio components in a 300-1500 Hz frequency band; and
an amplifier circuit configured to process signals representing the audio captured using the at least two microphones and generate driver signals for the at least one acoustic transducer,
wherein the at least one acoustic transducer and the at least two microphones are disposed on the head-worn acoustic device such that, in the head-worn state, a lobe of a radiation pattern of the at least one acoustic transducer is directed towards the ear canal of the user,
a feedforward microphone of the at least two microphones is positioned in an acoustic null in the radiation pattern of the at least one acoustic transducer and configured to capture audio originating from behind a head of the user as a portion of the input to the ANR circuit, and
a feedback microphone of the at least two microphones is positioned outside of a direct acoustic path between the at least one acoustic transducer and an ear of the user such that an amount of coupling between the at least one acoustic transducer and the feedback microphone is substantially equal to an amount of coupling between the at least one acoustic transducer and the ear of the user.

2. The acoustic device of claim 1 , wherein at least one microphone of the at least two microphones is disposed along a temple of an eyeglass frame.

3. The acoustic device of claim 2 , wherein the at least one microphone is disposed on a front portion of the eyeglass frame.

4. The acoustic device of claim 2 , wherein the at least one microphone is a portion of an array of multiple microphones disposed along the temple of the eyeglass frame.

5. The acoustic device of claim 4 , further comprising one or more processing devices configured to implement a beamforming process based on audio captured using the multiple microphones of the array.

6. The acoustic device of claim 5 , wherein the beamforming process is configured to preferentially capture audio from a gaze-direction of the user.

7. The acoustic device of claim 1 , wherein a power ratio of (i) a portion of output of the at least one acoustic transducer radiated towards the ear canal of the user and (ii) a portion of output of the at least one acoustic transducer radiated towards the feedforward microphone is at least 1 dB.

8. The acoustic device of claim 1 , wherein the at least one acoustic transducer is a part of an array of acoustic transducers.

9. The acoustic device of claim 1 , wherein in the head-worn state, a physical separation exists between the at least one acoustic transducer and the ear canal of the user.

10. The acoustic device of claim 1 , wherein in the head-worn state, a physical separation exists between the at least one acoustic transducer and a concha or pinna of the user.

11. The acoustic device of claim 1 , wherein the at least one acoustic transducer comprises an acoustic dipole.

12. A head-worn acoustic device comprising:
at least one acoustic transducer disposed such that, in a head-worn state, the at least one acoustic transducer is in an open-ear configuration in which an ear canal of a user of the head-worn acoustic device is at least partially unobstructed, and wherein the acoustic transducer is disposed within an arm of an eyeglass frame and configured (i) to radiate acoustic waves originating from a first side of the acoustic transducer through a first acoustic channel defined within the eyeglass arm and (ii) to radiate acoustic waves originating from a second side of the acoustic transducer through a second acoustic channel defined within the eyeglass arm;
at least two microphones configured to capture audio that is processed and played back through the at least one acoustic transducer;
an active noise reduction (ANR) circuit configured to operate on input from one or more microphones of the at least two microphones to preferentially reduce effects of (i) components of the audio captured using the at least two microphones from a first direction as compared to (ii) components of the audio captured using the at least two microphones from a second direction, wherein the ANR circuit is configured to reduce effects of audio components in a 300-1500 Hz frequency band,
wherein a feedforward microphone of the at least two microphones is positioned in an acoustic null in a radiation pattern of the at least one acoustic transducer and configured to capture audio originating from behind a head of the user as a portion of the input to the ANR circuit, and
wherein a feedback microphone of the at least two microphones is positioned outside of a direct acoustic path between the at least one acoustic transducer and an ear of the user such that an amount of coupling between the at least one acoustic transducer and the feedback microphone is substantially equal to an amount of coupling between the at least one acoustic transducer and the ear of the user;

an amplifier circuit configured to process signals representing the audio captured using a first subset of the at least two microphones to generate a first signal for the at least one acoustic transducer; and
an echo cancellation circuit configured to process the signals representing the audio captured using a second subset of the at least two microphones to generate a second signal for the at least one acoustic transducer, wherein a combination of the first signal and second signal reduces coupling between the at least one acoustic transducer and the at least two microphones by at least 3 dB.

13. The acoustic device of claim 1 , wherein the feedforward microphone is disposed at a back end of a temple of an eyeglass frame at a position wherein a power ratio of (i) a portion of output of the at least one acoustic transducer radiated towards the ear canal of the user and (ii) a portion of output of the at least one acoustic transducer radiated towards the feedforward microphone is at least 1 dB.

14. The acoustic device of claim 1 , wherein the feedback microphone is disposed along a temple of an eyeglass frame at a position wherein a power ratio of (i) a portion of output of the at least one acoustic transducer radiated towards the ear canal of the user and (ii) a portion of output of the at least one acoustic transducer radiated towards the feedback microphone is approximately 0 dB.

15. The acoustic device of claim 1 , wherein the eyeglass frame comprises a plurality of openings to allow acoustic radiation

Assignees

• Bose Corp

Inventors

• Sabin Andrew Todd
• Struzik Ryan C
• Wax Aric J
• Gauger Jr Daniel M

Classifications

• H04R2205/022

  Plurality of transducers corresponding to a plurality of sound channels in each earpiece of headphones or in a single enclosure · CPC title

• H04R1/105

  Earpiece supports, e.g. ear hooks (for stereophonic headphones H04R5/0335) · CPC title

• H04R2430/25

  Array processing for suppression of unwanted side-lobes in directivity characteristics, e.g. a blocking matrix · CPC title

• H04R2460/01

  Hearing devices using active noise cancellation · CPC title

• H04R1/1008

  Earpieces of the supra-aural or circum-aural type · CPC title