U.S. patent application number 12/251437 was filed with the patent office on 2009-10-01 for bone conduction hearing device having acoustic feedback reduction system.
This patent application is currently assigned to Cochlear Limited. Invention is credited to John L. Parker.
Application Number | 20090247813 12/251437 |
Document ID | / |
Family ID | 41117259 |
Filed Date | 2009-10-01 |
United States Patent
Application |
20090247813 |
Kind Code |
A1 |
Parker; John L. |
October 1, 2009 |
BONE CONDUCTION HEARING DEVICE HAVING ACOUSTIC FEEDBACK REDUCTION
SYSTEM
Abstract
A bone anchored hearing device, comprises: a housing, a sound
input element positioned in the housing configured to receive sound
signals, and a transducer positioned in the housing configured to
generate vibrations representative of the sound signals received by
the sound input device.
Inventors: |
Parker; John L.; (Roseville,
AU) |
Correspondence
Address: |
CONNOLLY BOVE LODGE & HUTZ LLP
1875 EYE STREET, N.W., SUITE 1100
WASHINGTON
DC
20006
US
|
Assignee: |
Cochlear Limited
Lane Cove, NSW
AU
|
Family ID: |
41117259 |
Appl. No.: |
12/251437 |
Filed: |
October 14, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61041185 |
Mar 31, 2008 |
|
|
|
Current U.S.
Class: |
600/25 |
Current CPC
Class: |
A61M 2210/0662 20130101;
H04R 25/606 20130101; Y10T 29/49572 20150115; H04R 25/00 20130101;
A61M 5/14276 20130101; A61M 2205/05 20130101; H04R 2460/13
20130101; H04R 25/70 20130101 |
Class at
Publication: |
600/25 |
International
Class: |
H04R 25/00 20060101
H04R025/00 |
Claims
1. A bone anchored hearing device, comprising: a housing; a sound
input element configured to receive sound signals and comprising a
moveable component configured to vibrate along a vibration axis in
response to the received sound signals; and a transducer positioned
in said housing configured to generate vibrations representative of
the sound signals received by said sound input element, wherein the
generated vibrations are directed along a displacement axis that is
substantially orthogonal to said vibration axis.
2. The bone anchored hearing device of claim 1, wherein said
moveable component has a substantially planar surface that is
substantially parallel to said displacement axis.
3. The bone anchored hearing device of claim 1, wherein said
transducer is a piezoelectric transducer.
4. The bone anchored hearing device of claim 3, wherein said
piezoelectric transducer is configured to control the amplitude of
the vibrations in the direction of the displacement axis.
5. The bone anchored hearing device of claim 1, wherein the sound
input element is mounted on a movable shaft.
6. The bone anchored hearing device of claim 3, wherein the movable
shaft is configured to adjust the sound input element to coincide
with the displacement axis.
7. The bone anchored hearing device of claim 1, wherein the sound
input element is a microphone.
8. The bone anchored hearing device of claim 1, wherein the
moveable component is a diaphragm.
9. A method of reducing the acoustic feedback in a bone conduction
hearing device, comprising: positioning a transducer in the bone
conduction hearing device such that the transducer generates
vibrations along one displacement axis; and positioning a sound
input element in the bone conduction hearing device such that a
moveable component of the sound input element vibrates along a
vibration axis that is substantially orthogonal with said
displacement axis.
10. The method of claim 9, wherein said sound input element is
positioned within a housing of the bone conduction hearing device
such that said moveable component has a sound impinging surface
that is substantially parallel to said displacement axis.
11. The method of claim 9, wherein said transducer is a
piezoelectric transducer.
12. The method of claim 11, wherein said piezoelectric transducer
is configured to control the amplitude of the vibrations in the
direction of the displacement axis.
13. The method of claim 9, wherein the sound input element is
mounted on a movable shaft.
14. The method of claim 13, further comprising adjusting the
movable shaft such that the sound input element coincides with the
displacement axis.
15. The method of claim 9, wherein the sound input element is a
microphone.
16. A system for reducing acoustic feedback in a bone anchored
hearing device, comprising: a transducer positioned within in the
bone conduction hearing device such that the transducer generates
vibrations along one displacement axis; and a sound input element
comprising a moveable component connected to the bone conduction
hearing device, said moveable component having a substantially
planar sound impinging surface that is substantially parallel with
said displacement axis such that said sound input device does not
substantially respond to vibrations generated by said
transducer.
17. The system of claim 16, wherein said moveable component
vibrates along a vibration axis that is substantially orthogonal to
said displacement axis.
18. The system of claim 16, wherein said transducer is a
piezoelectric transducer.
19. The system of claim 18, wherein said piezoelectric transducer
is configured to control the amplitude of the vibrations in the
direction of the displacement axis.
20. The system of claim 16, wherein the sound input element is
mounted on a movable shaft.
21. The system of claim 20, wherein the movable shaft is configured
to adjust the sound input element to coincide with the displacement
axis.
22. The system of claim 16, wherein the sound input element is a
microphone.
23. The system of claim 22, wherein the moveable component is a
diaphragm.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No. 61/041,185, entitled "Bone Conduction Devices For
The Rehabilitation OF Hearing Disorders," filed Mar. 31, 2008. This
application is hereby incorporated by reference herein.
BACKGROUND
[0002] 1. Field of the Invention
[0003] The present invention relates generally to bone anchored
hearing devices, and more particularly, to bone anchored hearing
devices having a feedback reduction system.
[0004] 2. Related Art
[0005] Hearing loss, which may be due to many different causes, is
generally of two types, conductive or sensorineural. In many people
who are profoundly deaf, the reason for their deafness is
sensorineural hearing loss. This type of hearing loss is due to the
absence or destruction of the hair cells in the cochlea which
transduce acoustic signals into nerve impulses. Various prosthetic
hearing implants have been developed to provide individuals who
suffer from sensorineural hearing loss with the ability to perceive
sound. One such prosthetic hearing implant is referred to as a
cochlear implant. Cochlear implants use an electrode array
implanted in the cochlea of a recipient to bypass the mechanisms of
the ear. More specifically, an electrical stimulus is provided via
the electrode array directly to the cochlea nerve, thereby causing
a hearing sensation.
[0006] Conductive hearing loss occurs when the normal mechanical
pathways to provide sound to hair cells in the cochlea are impeded,
for example, by damage to the ossicular chain to ear canal.
However, individuals who suffer from conductive hearing loss may
still have some form of residual hearing because the hair cells in
the cochlea are may remain undamaged.
[0007] Individuals who suffer from conductive hearing loss are
typically not candidates for a cochlear implant due to the
irreversible nature of the cochlear implant. Specifically,
insertion of the electrode array into a recipient's cochlea exposes
the recipient to risk of the destruction of the majority of hair
cells within the cochlea. The destruction of the cochlea hair cells
results in the loss of all residual hearing by the recipient.
[0008] Rather, individuals suffering from conductive hearing loss
typically receive an acoustic hearing aid, referred to as a hearing
aid herein. Hearing aids rely on principles of air conduction to
transmit acoustic signals through the outer and middle ears to the
cochlea. In particular, a hearing aid typically uses an arrangement
positioned in the recipient's ear canal to amplify a sound received
by the outer ear of the recipient. This amplified sound reaches the
cochlea and causes motion of the cochlea fluid and stimulation of
the cochlea hair cells.
[0009] Unfortunately, not all individuals who suffer from
conductive hearing loss are able to derive suitable benefit from
hearing aids. For example, some individuals are prone to chronic
inflammation or infection of the ear canal and cannot wear hearing
aids. Other individuals have malformed or absent outer ear and/or
ear canals as a result of a birth defect, or as a result of medical
conditions such as Treacher Collins syndrome or Microtia.
Furthermore, hearing aids are typically unsuitable for individuals
who suffer from single-sided deafness (total hearing loss only in
one ear). Cross aids have been developed for single sided deaf
individuals. These devices receive the sound from the deaf side
with one hearing aid and present this signal (either via a direct
electrical connection or wirelessly) to a hearing aid which is worn
on the opposite side. The disadvantage of this technology is the
need for the individual to wear two hearing aids and suffer the
complications of hearing aid use.
[0010] When an individual having fully functional hearing receives
an input sound, the sound is transmitted to the cochlea via two
primary mechanisms: air conduction and bone conduction. As noted
above, hearing aids rely primarily on the principles of air
conduction. In contrast, other devices, referred to as bone
conduction devices, rely predominantly on vibration of the bones of
the recipients skull to provide acoustic signals to the
cochlea.
[0011] Those individuals who cannot derive suitable benefit from
hearing aids may benefit from bone conduction devices. Bone
conduction devices function by converting a received sound into a
mechanical vibration representative of the received sound. This
vibration is then transferred to the bone structure of the skull,
causing vibration of the recipient's skull. This skull vibration
results in motion of the fluid of the cochlea. Hair cells inside
the cochlea are responsive to this motion of the cochlea fluid,
thereby generating nerve impulses resulting in the perception of
the received sound.
[0012] A known alternative to a normal air conduction hearing aid
is a bone conduction hearing aid which uses a hearing aid to drive
a vibrator which is pushed against the skull via a mechanism, such
as glasses or wire hoops. These devices are generally uncomfortable
to wear and, for some recipients, are incapable of generating
sufficient vibration to accurately present certain received sounds
to a recipient.
SUMMARY
[0013] In one aspect of the invention, a bone anchored hearing
device is provided. The device comprises: a housing, a sound input
element positioned in the housing configured to receive sound
signals, and a transducer positioned in the housing configured to
generate vibrations representative of the sound signals received by
the microphone, wherein the generated vibrations are directed along
a displacement axis, and wherein the sound input element is
substantially aligned with the displacement axis, such that
vibrations induced to the sound input element are reduced.
[0014] In another aspect of the invention, a method of reducing the
acoustic feedback in a bone conduction hearing device is provided.
The method, comprises: positioning a transducer in the bone
conduction hearing device such that the transducer generates
vibrations along one displacement axis, and positioning a sound
input element in the bone conduction hearing device such that it is
substantially aligned with the displacement axis, such that
vibrations induced to the sound input element are reduced.
[0015] In another aspect of the invention, a system for reducing
acoustic feedback in a bone anchored hearing device is provided.
The system comprises: a transducer positioned within in the bone
conduction hearing device such that the transducer generates
vibrations along one displacement axis, and a sound input element
positioned in the bone conduction hearing device and substantially
aligned with the displacement axis, such that the vibrations
induced to the sound input element are reduced.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Illustrative embodiments of the present invention are
described herein with reference to the accompanying drawings, in
which:
[0017] FIG. 1 is a perspective cutaway view of a human ear and a
bone conduction device implanted behind the ear in which
embodiments of the present invention may be advantageously
implemented;
[0018] FIG. 2A is a functional block diagram of an embodiment of a
bone conduction device in accordance with one embodiment of the
present invention;
[0019] FIG. 2B is a more detailed functional block diagram of the
bone conduction device of FIG. 2A in accordance with one embodiment
of the present invention;
[0020] FIG. 3 is an exploded view of an embodiment of a bone
conduction device in accordance with one embodiment of FIG. 2B in
accordance with one embodiment of the present invention;
[0021] FIG. 4A is a schematic diagram of a bone conduction device
with an internal sound input element suspended from the housing via
a vibration dampening coupling member;
[0022] FIG. 4B is a top perspective view of a bone conduction
device with a sound input element mounted externally to said
housing via a vibration dampening coupling member;
[0023] FIG. 4C is a cross sectional view of the flexible connector
of FIG. 4B taken along line 4C-4C in FIG. 4B;
[0024] FIG. 4D is a schematic diagram of a bone conduction device
with an internal sound input element suspended from the housing via
a plurality of vibration dampening coupling member;
[0025] FIG. 5A is a schematic diagram of a bone conduction device
with a microphone positioned such that a diaphragm of the
microphone is oriented substantially parallel to the transducer
vibrations in accordance with one embodiment of the present
invention;
[0026] FIG. 5B is a schematic diagram showing the relative
orientation of a diaphragmatic microphone and its concomitant
vibration axis and the displacement axis of the transducer, in
accordance with one embodiment of the present invention;
[0027] FIG. 5C is a simplified diagram of a dynamic microphone in
accordance with one embodiment of the present invention;
[0028] FIG. 5D is a simplified diagram of a condenser microphone in
accordance with one embodiment of the present invention;
[0029] FIG. 6A is a system block diagram of a bone conduction
device with a bone anchored housing and a separate microphone
housing;
[0030] FIG. 6B is a perspective view of a bone conduction device
having a microphone separated from the bone anchored housing;
and
[0031] FIG. 7 is a flow chart illustrating the implantation of the
bone conduction device of FIGS. 6A and 6B in accordance with one
embodiment of the present invention.
DETAILED DESCRIPTION
[0032] Embodiments of the present invention are generally directed
to a bone conduction device for converting a received acoustic
sound signal into a mechanical force for delivery to a recipient's
skull. The bone conduction device includes a housing having a sound
input component, such as microphone, to receive the acoustic sound
signal, an electronics module configured to generate an electrical
signal representing the acoustic sound signal, and a transducer to
convert the electrical signal into a mechanical force for delivery
to the recipient's skull. The transducer is configured to generate
vibrations substantially along one displacement axis.
[0033] FIG. 1 is a perspective view of embodiments of a bone
conduction device 100 in which embodiments of the present invention
may be advantageously implemented. In a fully functional human
hearing anatomy, outer ear 101 comprises an auricle 105 and an ear
canal 106. A sound wave or acoustic pressure 107 is collected by
auricle 105 and channeled into and through ear canal 106. Disposed
across the distal end of ear canal 106 is a tympanic membrane 104
which vibrates in response to acoustic wave 107. This vibration is
coupled to oval window or fenestra ovalis 110 through three bones
of middle ear 102, collectively referred to as the ossicles 111 and
comprising the malleus 112, the incus 113 and the stapes 114. Bones
112, 113 and 114 of middle ear 102 serve to filter and amplify
acoustic wave 107, causing oval window 110 to articulate, or
vibrate. Such vibration sets up waves of fluid motion within
cochlea 115. Such fluid motion, in turn, activates cochlear hair
cells (not shown). Cochlear hair cells come in two anatomically and
functionally distinct types: the outer and inner hair cells.
Activation of one or more types of these hair cells causes
appropriate nerve impulses to be transferred through the spiral
ganglion cells and auditory nerve 116 to the brain (not shown),
where they are perceived as sound.
[0034] FIG. 1 also illustrates the positioning of bone conduction
device 100 relative to outer ear 101, middle ear 102 and inner ear
103 of a recipient of device 100. As shown, bone conduction device
100 may be positioned behind outer ear 101 of the recipient.
[0035] In the embodiments illustrated in FIG. 1, bone conduction
device 100 comprises a housing 125 having a microphone 126
positioned therein or thereon. Housing 125 is coupled to the body
of the recipient via coupling 140. As described below, bone
conduction device 100 may comprise a sound processor, a transducer,
transducer drive components and/or various other electronic
circuits/devices.
[0036] In accordance with embodiments of the present invention, an
anchor system (not shown) may be implanted in the recipient. As
described below, the anchor system may be fixed to bone 136. In
various embodiments, the anchor system may be implanted under skin
132 within muscle 134 and/or fat 128. In certain embodiments, a
coupling 140 attaches device 100 to the anchor system.
[0037] A functional block diagram of one embodiment of bone
conduction 100, referred to as bone conduction device 200, is shown
in FIG. 2A. In the illustrated embodiment, a sound 207 is received
by a sound input element 202. In some embodiments, sound input
element 202 is a microphone configured to receive sound 207, and to
convert sound 207 into an electrical signal 222. As described
below, in other embodiments sound 207 may received by sound input
element 202 as an electrical signal.
[0038] As shown in FIG. 2A, electrical signal 222 is output by
sound input element 202 to an electronics module 204. Electronics
module 204 is configured to convert electrical signal 222 into an
adjusted electrical signal 224. As described below in more detail,
electronics module 204 may include a sound processor, control
electronics, transducer drive components, and a variety of other
elements.
[0039] As shown in FIG. 2A, a transducer 206 receives adjusted
electrical signal 224 and generates a mechanical output force that
is delivered to the skull of the recipient via an anchor system 208
coupled to bone conduction device 200. Delivery of this output
force causes one or more of motion or vibration of the recipients
skull, thereby activating the hair cells in the cochlea via cochlea
fluid motion.
[0040] FIG. 2A also illustrates a power module 210. Power module
210 provides electrical power to one or more components of bone
conduction device 200. For ease of illustration, power module 210
has been shown connected only to interface module 212 and
electronics module 204. However, it should be appreciated that
power module 210 may be used to supply power to any electrically
powered circuits/components of bone conduction device 200.
[0041] Bone conduction device 200 further includes an interface
module 212 that allows the recipient to interact with device 200.
For example, interface module 212 may allow the recipient to adjust
the volume, alter the speech processing strategies, power on/off
the device, etc. Interface module 212 communicates with electronics
module 204 via signal line 228.
[0042] In the embodiment illustrated in FIG. 2A, sound pickup
device 202, electronics module 204, transducer 206, power module
210 and interface module 212 have all been shown as integrated in a
single housing, referred to as housing 225. However, it should be
appreciated that in certain embodiments of the present invention,
one or more of the illustrated components may be housed in separate
or different housings. Similarly, it should also be appreciated
that in such embodiments, direct connections between the various
modules and devices are not necessary and that the components may
communicate, for example, via wireless connections.
[0043] FIG. 2B provides a more detailed view of bone conduction
device 200 of FIG. 2A. In the illustrated embodiment, electronics
module 204 comprises a sound processor 240, transducer drive
components 242 and control electronics 246. As explained above, in
certain embodiments sound input element 202 comprises a microphone
configured to convert a received acoustic signal into electrical
signal 222. In other embodiments, as detailed below, sound input
element 202 receives sound 207 as an electrical signal.
[0044] In embodiments of the present invention, electrical signal
222 is output from sound input element 202 to sound processor 240.
Sound processor 240 uses one or more of a plurality of techniques
to selectively process, amplify and/or filter electrical signal 222
to generate a processed signal 224A. In certain embodiments, sound
processor 240 may comprise substantially the same sound processor
as is used in an air conduction hearing aid. In further
embodiments, sound processor 240 comprises a digital signal
processor.
[0045] Processed signal 226A is provided to transducer drive
components 242. Transducer drive components 242 output a drive
signal 224B, to transducer 206. Based on drive signal 224B,
transducer 206 provides the output force to the skull of the
recipient.
[0046] For ease of description the electrical signal supplied by
transducer drive components 242 to transducer 206 has been referred
to as drive signal 224B. However, it should be appreciated that
processed signal 224B may comprise an unmodified version of
processed signal 224A.
[0047] As noted above, transducer 206 generates an output force to
the skull of the recipient via anchor system 208. As shown in FIG.
2B, anchor system 208 comprises a coupling 260 and an implanted
anchor 262. Coupling 260 may be attached to one or more of
transducer 206 or housing 225. For example, in certain embodiments,
coupling 260 is attached to transducer 206 and vibration is applied
directly thereto. In other embodiments, coupling 260 is attached to
housing 225 and vibration is applied from transducer 206 through
housing 225.
[0048] As shown in FIG. 2B, coupling 260 is coupled to an anchor
implanted in the recipient, referred to as implanted anchor 262. As
explained with reference to FIG. 3, implanted anchor 262 provides
an element that transfers the vibration from coupling 260 to the
skull of the recipient.
[0049] As noted above, a recipient may control various functions of
the device via interface module 212. Interface module 212 includes
one or more components that allow the recipient to provide inputs
to, or receive information from, elements of bone conduction device
200.
[0050] As shown, control electronics 246 may be connected to one or
more of interface module 212, sound pickup device 202, sound
processor 240 and/or transducer drive components 242. In
embodiments of the present invention, based on inputs received at
interface module 212, control electronics 246 may provide
instructions to, or request information from, other components of
bone conduction device 200. In certain embodiments, in the absence
of user inputs, control electronics 246 control the operation of
bone conduction device 200.
[0051] FIG. 3 illustrates an exploded view of one embodiment of
bone conduction 200 of FIGS. 2A and 2B, referred to herein as bone
conduction device 300. As shown, bone conduction device 300
comprises an embodiment of electronics module 204, referred to as
electronics module 304. As explained above, included within
electronics module 304 are a sound processor, transducer drive
components and control electronics. For ease of illustration, these
components have not been illustrated in FIG. 3.
[0052] In the illustrated embodiment, electronics module 304
includes a printed circuit board 314 (PCB) to electrically connect
and mechanically support the components of electronics module 304.
Attached to PCB 314 are one or more sound input elements, shown as
microphones 302 to receive a sound.
[0053] In the illustrated embodiment, bone conduction device 300
further comprises battery shoe 310 for supplying power to
components of device 300. Battery shoe 310 may include one or more
batteries. In certain embodiments, PCB 314 is attached to a
connector 376. Connector 376 is configured to mate with battery
shoe 310. In certain embodiments, connector 376 and battery shoe
310 may be releasably snap-locked to one another. Furthermore, in
such embodiments, one or more battery connects (not shown) are
disposed in connector 376 to electrically connect battery shoe 310
with electronics module 304.
[0054] In the embodiment illustrated in FIG. 3, bone conduction
device 300 further includes a two-part housing 325, comprising
first housing portion 325A and second housing portion 325B. Housing
portions 325 are configured to mate with one another to
substantially seal bone conduction device 300.
[0055] In the embodiment of FIG. 3, first housing portion 325A has
an opening therein for receiving battery shoe 310. In such
embodiments, battery shoe protrudes through first housing portion
325A and may be removed or inserted by the recipient. Also in the
illustrated embodiment, microphone covers 372 are releasably
attached to first housing portion 325A. Microphone covers 372
provide a barrier over microphones 302 to protect microphones 302
from dust, dirt or other debris.
[0056] Bone conduction device 300 further includes an embodiment of
interface module 212, referred to herein as interface module 312.
Interface module 312 is configured to provide or receive user
inputs from the recipient.
[0057] Also as shown in FIG. 3, bone conduction device 300
comprises an embodiment of transducer 206, referred to as
transducer 306. Transducer 306 generates an output force that
causes movement of the cochlea fluid so that a sound may be
perceived by the recipient. The output force may result in
mechanical vibration of the recipient's skull, or in physical
movement of the skull about the neck of the recipient. As noted
above, in certain embodiments, bone conduction device 300 delivers
the output force to the skull of the recipient via an anchor system
308. Anchor system 308 comprises a coupling 360 and implanted
anchor 362. In the embodiment illustrated in FIG. 3, coupling 360
is configured to be attached to second housing portion 325B. As
such, in this embodiment, vibration from transducer 306 is provided
to coupling 360 through housing 325B. In the embodiment shown in
FIG. 3, an opening 368 is provided in second housing portion 325B.
A screw (not shown) may be inserted through opening 368 to attach
transducer 306 to coupling 360. In such embodiments, an O-ring 380
may be provided to seal opening 368 around the screw.
[0058] As noted above, anchor system 308 includes implanted anchor
362. Implanted anchor 362 comprises a bone screw 366 implanted in
the skull of the recipient and an abutment 364. In an implanted
configuration, screw 366 protrudes from the recipient's skull
through the skin. Abutment 364 is attached to screw 366 above the
recipient's skin. In other embodiments, abutment 364 and screw 366
may be integrated into a single implantable component. Coupling 360
is configured to be releasably attached to abutment 364 to create a
vibratory pathway between transducer 306 and the skull of the
recipient.
[0059] In alternative embodiments of the present invention, bone
conduction device 300 may comprise one or more additional sound
input element. For example, bone conduction device 300 may
comprises an electrical input. In such embodiments, the electrical
input is configured to connect device 300 to external equipment and
receive an electrical sound signal directly therefrom. The
electrical input may permit bone conduction device 300 to be
connected to, for example, FM hearing systems, MP3 players,
televisions, mobile phones, etc.
[0060] In still other embodiments, a further sound input element in
the form of a telecoil may be integrated in, or connected to, bone
conduction device 300. The telecoil permits bone conduction device
300 to receive input signals from, for example, a telephone or
other similar device.
[0061] FIG. 4A illustrates one embodiment of bone conduction device
200, depicted as bone conduction device 400, which includes a
housing 402 and a coupler 404 for removeably attaching the housing
402 to an anchor, such as anchor 262 (FIG. 2B). In this embodiment,
the housing 402 includes, among other components, a microphone or
sound input element 406 and a transducer 408. Additionally, the
housing may include a sound processor, an electronics module, a
power source and an interface (each of each is not shown), or any
other suitable component, as described herein. The sound input
element, as described above, receives sound waves, which are sent
to the sound processor. Sound processor in turn may amplify or
alter the signal and send this altered signal to the transducer to
impart vibrations to the anchor.
[0062] In one embodiment, sound input element 406 is suspended from
the housing or coupled to any other suitable portion of the bone
anchored device 400 using flexible shaft or vibration dampening
coupling member 410. By attaching the sound input element in this
manner, the sound input element may be isolated from the mechanical
vibrations generated by the transducer, thus reducing feedback
through the sound input element. In other words, the recipient of
the bone conduction device will have feedback percept substantially
reduced or eliminated.
[0063] In one embodiment, the sound input element is mounted
internally of housing 402. The coupling member may be a rubber
sleeve or other configuration that is configured to allow the sound
input element to frictionally fit therein. In one embodiment,
coupling member may be coupled to the sound input element via
opening 411 at one end thereof that allows access to an internal
space therein. The sound input element may have a diameter slightly
larger than opening 411, thus creating a secure, but removable fit
for the sound input element. In other embodiments, the coupling is
a connector formed of other suitable material, such as silicon,
foam and/or any other suitable material or combination of
materials. It is noted that each of these materials may have a
different spring constant or ability to dampen the vibrations.
[0064] In one embodiment, coupling member 410 is coupled to housing
402 at point or location 409 and to the sound input element 406 at
a point or location 413. In this embodiment, the vibrations
imparted to the sound imparted to the sound input element are
reduced or attenuated from point or location 409 to point or
location 413. In other words, due to the spring constant and the
attenuation of the coupling member 410, the vibrations imparted to
the sound input element are reduced along the length of the
coupling member 410.
[0065] In some embodiments, an additional vibration absorbing
material may disposed between the coupling member and the sound
input element to further attenuate the vibrations generated by said
transducer. For example, the coupling member may be a rubber sleeve
and the additional vibration material may be a layer of foam
between the coupling and the sound input element.
[0066] In one embodiment, the coupling may be a spring or flexible
shaft with a low spring constant; however, the spring constant may
be any desired spring constant. The flexible shaft may be formed
from metal or plastic or any other suitable material or combination
of materials. In this embodiment, the sound input element may be
detachable from the housing, such that the spring constant or
stiffness of the flexible shaft may be easily changeable or
selectable as the power levels of the bone conduction device
increase or changes. In other words, some spring constants my
produce less feedback based on the amplitude of vibration of the
transducer. In this embodiment, the flexible shaft may be selected
from a plurality of flexible shafts, each flexible shaft having a
different spring constant or stiffness.
[0067] FIG. 4B illustrates one embodiment of bone conduction device
200, depicted as bone conduction device 450. In this embodiment,
bone conduction device 450, is substantially similar to device 400;
however, sound input element or microphone 452 is mounted
externally of housing 454 at point or location 458. In this
embodiment, vibration dampening coupling member is flexible shaft
or extension 456 that extends outwardly and externally from housing
454. In some embodiments, the shaft 456 has a substantially
rectangular cross section, wherein the width 459 is substantially
greater than its height 461 (FIG. 4C). The sound input element is
coupled to the shaft at point or location 458 along the width 459.
Such a configuration will enable the shaft to attenuate the
vibrations imparted to the sound input element. In this embodiment,
the vibrations imparted to the sound imparted to the sound input
element are reduced or attenuated from or location 455 to point or
location 458. In other words, due to the spring constant and the
attenuation of the shaft 456, the vibrations imparted to the sound
input element are reduced along the length of the shaft 456. By
mounting the sound input element externally in such a manner,
feedback is isolated, while allowing for the remaining components
to contribute to the mass that is vibrated.
[0068] The flexible shaft may be formed from any suitable flexible
material, such as rubber, metal, plastic, silicon, and/or any other
suitable material or the flexible shaft may be a spring, as
described above. Disposed at the distal end 458 of the flexible
shaft is sound input element 452. As with the embodiment of FIG.
4A, an additional vibration absorbing material may disposed between
the coupling member and the sound input element to further
attenuate the vibrations generated by said transducer.
[0069] Additionally, the sound input element and/or the flexible
shaft may be detachable form the housing, such that the flexible
shaft may be selected from a plurality of flexible shafts, each
flexible shaft having a different spring constant or stiffness.
Typically, the spring constant is be changed or selected based on
the power level of the output of the transducer; however, any
suitable spring constant may be selected. As with the above
described embodiments, housing 454 generally includes a transducer,
an electronics module, an interface and a power module (each of
which is not shown), or any other suitable component, as described
herein.
[0070] FIG. 4D illustrates another embodiment of bone conduction
device 200, depicted as bone conduction device 470. In this
embodiment, bone conduction device 470, is substantially similar to
device 400; however, sound input element or microphone 472 is
mounted using a plurality of vibration dampening coupling members
474a-d. In this embodiment, each of the vibration dampening
coupling members 474a-d may a spring configured to reduce or
attenuate the vibrations imparted to the sound input element 472.
Each vibration dampening coupling members 474a-d is coupled to the
housing 476 at a first or location 478a-d, respectively, and
coupled to the sound input element 472 at a second or location
480a-d, respectively. As described above, the vibrations imparted
to the sound input element are reduced or attenuated from points or
locations 478a-d to points or locations 480a-d. In other words, due
to the spring constant and the attenuation of the shaft 456, the
vibrations imparted to the sound input element are reduced along
the length of the vibration dampening coupling members 474a-d.
[0071] As with the embodiments described herein, vibration
dampening coupling members 474a-d may be removable and replaceable
by other vibration dampening coupling members having different
spring constants or vibration dampening properties. Additionally,
each vibration dampening coupling members 474a-d may have different
vibration dampening properties.
[0072] FIG. 5A illustrates one embodiment of bone conduction device
200, depicted as bone conduction device 500. As described above,
conduction device 500 may include a housing 502 and a coupler 504
for removeably attaching the housing 502 to an anchor, such as
anchor 262 (FIG. 2B). In this embodiment, housing 502 includes,
among other components, a microphone or sound input element 506
connected to housing 502 via extension arms 503, and a transducer
508. As with the above described embodiments, housing 502 may
included, an electronics module, an interface and a power module
(each of which is not shown), or any other suitable component. The
sound input element, as described above, receives sound waves,
which are sent to the sound processor. Sound processor in turn may
amplify or alter the signal and send this altered signal to the
transducer to impart vibrations to the anchor, along a displacement
axis 510.
[0073] In one embodiment, sound input element is positioned and
arranged such that the moveable component such as a diaphragm 505
of the sound input element 506 is configured to vibrate or move due
to acoustic sound is substantially parallel with displacement axis
510. As such, movable component 505 vibrates along a vibration axis
that is substantially orthogonal with displacement axis 510.
[0074] FIG. 5B is a schematic diagram of an exemplary moveable
component, diaphragm 558 of a sound input element (not shown)
according to one embodiment of the present invention. As
illustrated, movable component 558 is mounted such that its sound
impinging surface resides in a plane 550 which is substantially
parallel to displacement axis 510. By configuring the moveable
component to be positioned in a plane that is substantially
parallel to the displacement axis, the moveable component vibrates
along a vibration axis 552 that is substantially orthogonal with
displacement axis 510. Thus, the feedback to the sound input
element is reduced or substantially eliminated.
[0075] FIG. 5C illustrates an embodiment of the sound input element
for bone conduction device 500 in which the sound input element is
shown as dynamic microphone 520. Microphone 520 generally includes
a housing 521 which encloses a movable component or diaphragm 522,
a magnet 524 and internal wiring 526 that conveys the signal to an
amplifier. The microphone is configured to operate by having the
diaphragm vibrate when contacted by sound. The diaphragm is
attached to and thus, vibrates internal wiring 526, which is
configured as a coil. The movement of the coil in the magnetic
field generates small changes in electrical pressure or voltage,
producing a varying current in the coil through electromagnetic
induction.
[0076] FIG. 5D illustrates an embodiment of the sound input element
in which the sound input element is shown as a condenser microphone
530. Microphone 530 includes a housing 532 which encloses a movable
component or diaphragm 534, a plate 536, an amp 538 and a battery
540. In this embodiment, diaphragm 534 and plate 536 are oppositely
charged such that when moved closer or farther apart, a change in
voltage is created. This voltage change or audio signal is then
transmitted through wiring 542. Since the change in voltage is
typically small (e.g., a millionth of a volt) the signal may be
amplified by amp 538. The electrical charge may be a direct current
voltage supplied by battery 540 and may be applied through the same
wiring 542 that carries the alternating current voltage of the
audio signal.
[0077] In some embodiments, the diaphragm of a microphone (e.g.,
diaphragm 522 or 534) may be the moveable component that resides in
a plane parallel to the displacement axis 510. By configuring the
diaphragm to reside or be positioned in a plane that is
substantially parallel to the displacement axis, the diaphragm does
not vibrate or the vibrations are reduced when the transducer
vibrates. Thus, the feedback to the microphone will be reduced or
substantially eliminated. It is noted that the embodiments shown in
FIGS. 5C and 5D are merely exemplary and the invention is not
limited to microphones or sound input devices having these types of
diaphragms.
[0078] In one embodiment, transducer 508 is a piezoelectric
transducer that is configured to control the amplitude of the
vibrations in the direction of the displacement axis. The range of
the output force of the transducer 508 may be preselected by the
clinician or the recipient to accommodate certain threshold limits
for the recipient's hearing. The output force for the transducer is
generally a function of the mass and the velocity of the transducer
508 moving along the displacement axis 510 and the mass of the
moving part of the transducer.
[0079] In one embodiment, the sound input element is mounted on a
movable shaft. The movable shaft is configured to adjust the sound
input element to coincide with the displacement axis. Thus, in this
embodiment, a clinician or the recipient may adjust the direction
of the movable shaft to improve the sound percept of the
recipient.
[0080] To achieve the most desired feedback reduction, the
recipient's sound percept any be determined in any suitable manner.
For example, the recipient may listen to acoustic sound using the
bone conduction device. The sound input element may then be
adjusted on the moveable shaft to more precisely coincide with the
displacement axis. This adjustment may be made manually or using
any other suitable device. Once the sound input element is
adjusted, the recipient's sound percept may be determined again.
This procedure may be repeated until optimum feedback
reduction.
[0081] FIGS. 6A and 6B illustrate embodiments of bone conduction
device 200, depicted as bone conduction device, in which a sound
input element or microphone 602 is located in a separate housing,
remote from transducer 604, to reduce feedback percept by a
recipient. By positioning the second housing remote from the first
housing, transducer vibrations are substantially reduced in the
sound input element.
[0082] In this embodiment, bone conduction device 600 includes a
first housing 606 and a second housing 608. First housing 606
includes microphone or sound input element 602, a battery 609 and
an IR transmitter 610. Second housing includes transducer 604, an
IR receiver 612, an amp 614, electronics module (e.g., 204), an
interface (e.g., 212) and a battery 616. It is noted that the
components included in each housing are merely exemplary and each
housing may include any components desired, as long as the
microphone and the transducer are positioned in separate housings.
The components of bone conduction device 600 operate in
substantially similar manner to those described above.
[0083] In some embodiments, first housing 606 is positioned behind
the ear or in the ear; however, first housing 606 may be positioned
in any suitable area or place on the recipient. For example,
housing 606 may be positioned in the ear, behind the ear, remotely
from the ear or any other portion of the recipient's body. In
another embodiment, housing 606 may be implanted or attached to
skull 619. Second housing 608 may be removeably attached to the
anchor 617 using a coupling member 615 in a substantially similar
manner as described in the above embodiments or in any other manner
described herein.
[0084] In this embodiment, bone conduction device 600 operates in a
similar manner as described above; however, the signal 620 from the
sound input element 602 is sent via an infrared (IR) link 618. By
separating the sound input element from the transducer, the
microphone is not subject to the direct vibrations within housing
608 and thus, feedback is reduced. It is noted that communication
between the microphone and the transducer may be any type of
wireless communication (e.g., IR, radio frequency (RF) or any other
suitable communications) or the communications can be through a
wired connection. In the wired connection, the device would
communicate in a substantially similar to described above, except
the signal from the microphone would be sent to housing 608 through
an external wire, as discussed below.
[0085] It is noted that, in this embodiment, the housings 606 and
608 do not necessarily need to house the above described components
and each housing may have positioned therein any of the above
described or other suitable components positioned therein, as long
as the sound input element and the transducer are separate. For
example, in one embodiment, second housing 608 may only include
transducer 604 battery, IR receiver 612 and a battery 616, while
housing 606 contains the remainder of the components.
[0086] In some embodiments, as depicted in FIG. 6B, the microphone
or sound input element is connected via wires 622 to housing 608.
In this embodiment, housing 608 may include all the bone conduction
hearing device components other than sound input element 602. As
noted housing 606 may be a small platform to which sound input
element is attached. In this embodiment, feedback may be isolated,
while allowing for the remaining components to contribute to the
mass that is vibrated.
[0087] Microphone 602 may be connected to the ear using clip 624 or
in any suitable manner. For example, microphone may be positioned
in or on the ear, on any portion of the recipient's head and/or
body. Thus, the microphone may be concealed in a suitable area or
may be attached to the body, ear or head for optimum reception.
[0088] FIG. 7 illustrates the general procedure for implanting the
bone conduction device 600. As noted in block 702, an anchor (e.g.,
anchor 262) is implanted into the skull of the recipient. As
discussed above, the anchor system may be fixed to bone 136. In
various embodiments, the anchor system may be implanted under skin
132 within muscle 134 and/or fat 128. In block 704, a housing that
includes a transducer (e.g., 608) is coupled to the anchor.
[0089] At block 706, a housing that includes a microphone is
positioned adjacent the skull of the recipient (e.g., housing 606).
As discussed herein, the microphone housing may be placed in the
ear, behind the ear or any suitable position on the recipient.
Communications between the transducer housing and the microphone
housing may then be established, at block 708. such communications
may be wireless or wired and may use any type of communication
described herein.
[0090] Further features and advantages of the present invention are
described in U.S. Provisional Application No. 61/041,185, entitled
"Bone Conduction Devices For The Rehabilitation OF Hearing
Disorders," filed Mar. 31, 2008. This application is hereby
incorporated by reference herein.
[0091] While various embodiments of the present invention have been
described above, it should be understood that they have been
presented by way of example only, and not limitation. It will be
apparent to persons skilled in the relevant art that various
changes in form and detail can be made therein without departing
from the spirit and scope of the invention. Thus, the breadth and
scope of the present invention should not be limited by any of the
above-described exemplary embodiments, but should be defined only
in accordance with the following claims and their equivalents. All
patents and publications discussed herein are incorporated in their
entirety by reference thereto.
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