U.S. patent application number 14/555899 was filed with the patent office on 2015-06-04 for medical device having an impulse force-resistant component.
The applicant listed for this patent is Cochlear Limited. Invention is credited to Wim BERVOETS.
Application Number | 20150156594 14/555899 |
Document ID | / |
Family ID | 53266438 |
Filed Date | 2015-06-04 |
United States Patent
Application |
20150156594 |
Kind Code |
A1 |
BERVOETS; Wim |
June 4, 2015 |
MEDICAL DEVICE HAVING AN IMPULSE FORCE-RESISTANT COMPONENT
Abstract
A vibrator including a housing, a transducer mounted in the
housing such that there is a gap between the housing and
transducer; and an impulse force damper that substantially fills
the gap. Such a damper includes: a first layer in contact with the
housing; and a second layer in contact with the transducer and the
first layer; wherein substantially no adhesion is exhibited between
the first and second layers or between at least one of the first
and second layers and at least one of the housing and the
transducer.
Inventors: |
BERVOETS; Wim; (Wilrijk,
BE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Cochlear Limited |
Macquarie University |
|
AU |
|
|
Family ID: |
53266438 |
Appl. No.: |
14/555899 |
Filed: |
November 28, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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61910227 |
Nov 29, 2013 |
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Current U.S.
Class: |
600/25 |
Current CPC
Class: |
H04R 2460/13 20130101;
H04R 2225/67 20130101; H04R 1/2876 20130101; H04R 17/00 20130101;
H04R 31/006 20130101; H04R 25/606 20130101 |
International
Class: |
H04R 25/00 20060101
H04R025/00; H04R 1/10 20060101 H04R001/10 |
Claims
1. A vibrator comprising: a housing; a transducer positioned within
the housing such that there is a gap between the transducer and
housing; and an impulse force damper, disposed in the gap between
the housing and at least a portion of the transducer, configured to
mechanically isolate at least a portion of the transducer and the
housing, and to minimize impulse forces applied to the transducer
relative to that which would be the case in the absence of the
impulse force damper.
2. The vibrator of claim 1, wherein for at least one of a plurality
of regions of the gap between the housing and the at least a
portion of the transducer, the impulse force damper fills the gap
in that at least one region, and wherein said impulse force damper
is configured to minimize adhesion between abutting surfaces of at
least one of the damper/housing interface and the damper/transducer
interface.
3. The vibrator of claim 1, wherein said damper is formed of an
elastic damping material.
4. The vibrator of claim 3, wherein, in response to a decrease in
distance between the housing and transducer in the at least one
region, the elastic damping material deforms by laterally expanding
thereby increasing dimensions of the at least one region.
5. The vibrator of claim 2, wherein the damper is configured to
provide at least an effectively negligible load on the transducer
relative to that which would be the case in the absence of the
damper.
6. The vibrator of claim 1, wherein the damper has a mass that is
effectively insubstantial relative to the mass of the transducer so
as to minimize an effect on an output response of the vibrator
relative to that which would be the case in the absence of the
presence of the damper.
7. The vibrator of claim 1, wherein the damper comprises: a first
layer of a first material in contact with one of either the housing
and the transducer; and a second layer of a second material in
contact with the other of either the housing and the transducer,
wherein the first and second layers have abutting surfaces defining
a first layer/second layer interface.
8. The vibrator of claim 7, wherein the first and second materials
are antifriction materials with respect to each other.
9. The vibrator of claim 8, wherein one of the first and second
materials is an elastic damping material.
10. The vibrator of claim 9, wherein the one of the first and
second layers formed by the elastic damping material is a
substantial volume of the damper, and the other of the first and
second layers has a negligible thickness.
11. The vibrator of claim 10, wherein the other of the first and
second layers substantially conforms to manufacturing and assembly
tolerances in the surface of the abutting surface of one of the
housing and transducer.
12. A bone conduction device, comprising: a mass; an actuator
configured to move the mass to generate vibrations to evoke a
hearing percept; and a housing encompassing the mass and the
actuator, wherein a damper is located in a space between a housing
wall of the housing and the mass.
13. The bone conduction device of claim 12, further including: an
arm, wherein the mass is located at a first end of the arm, and the
arm is connected to the actuator at a location away from the first
end of the arm, wherein the actuator moves the arm, thereby moving
the mass.
14. The bone conduction device of claim 12, wherein: the damper
extends from the mass to the wall of the housing.
15. The bone conduction device of claim 12, wherein: the damper
includes a damper material and an isolation layer that separates
the damper material from one of the mass and the housing wall.
16. The bone conduction device of claim 12, wherein: the damper is
a first damper; the bone conduction device includes a second damper
located in a second space between another portion of the housing
and another side of the mass on an opposite side of the mass from
the first damper.
17. The bone conduction device of claim 12, wherein: the bone
conduction device is configured such that output of the bone
conduction device to evoke a hearing percept is at least
effectively the same as that which would be the case in the absence
of the damper being present between the mass and the housing
wall.
18. A method of damping an impulse force to which a vibrator for an
auditory prosthesis is susceptible, the vibrator including a
housing, a transducer mounted in the housing and a multilayer
damper disposed between the housing and the transducer, the method
comprising: compressing the damper in response to the impulse
force, the compressing including: deforming at least one layer of
the damper so as to dissipate energy of the impulse force; and
slipping, due to there being substantially no adhesion between one
or more of: two layers of the damper with respect to each other; at
least one layer of the damper with respect to the housing; and at
least one layer of the damper with respect to the transducer.
19. The method of claim 18, further comprising: imposing, in a
quiescent state, substantially no static preload on the transducer
by the damper.
20. The method of claim 18, wherein the damper is configured to
cause a substantially insignificant effect on the frequency
response of the vibrator.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims priority to U.S. Provisional
Patent Application No. 61/910,227, filed on Nov. 29, 2013, naming
Wim Bervoets as an inventor, the contents of that application being
incorporated herein in its entirety.
BACKGROUND
[0002] 1. Field of the Disclosure
[0003] The present disclosure relates generally to medical devices,
and more particularly, to medical devices having an
impulse-force-resistant component.
[0004] 2. Related Art
[0005] Hearing loss, which may be due to many different causes, is
generally of two types, conductive and/or sensorineural. Conductive
hearing loss occurs when the normal mechanical pathways of the
outer and/or middle ear are impeded, for example, by damage to the
ossicular chain or ear canal. Sensorineural hearing loss occurs
when there is damage to the inner ear, or to the nerve pathways
from the inner ear to the brain.
[0006] Individuals suffering from conductive hearing loss typically
receive an auditory prosthesis that provides acoustic stimulation,
e.g., a hearing aid. Typically, a hearing aid is positioned in the
ear canal or on the outer ear to amplify received sound. This
amplified sound is delivered to the cochlea through the normal
middle ear mechanisms resulting in the increased perception of
sound by the recipient.
[0007] Individuals who suffer from conductive hearing loss
typically have some form of residual hearing because the cochlea
hair cells are often undamaged. As a result, individuals suffering
from conductive hearing loss might receive an auditory prosthesis
that provides mechanical stimulation to cause a hearing percept.
Such prostheses include, for example, bone conduction devices and
middle ear implants.
[0008] Auditory prostheses such as bone conduction devices function
by converting a received sound signal into a mechanical vibration
representative of the received sound. An electromechanical
transducer can be used for such conversion. The vibrations are
delivered or applied to the skull (cranium, mandible or teeth), and
travel through the bone structure of the skull. This skull
vibration results in relative motion of the cochlea and cochlea
fluid or perilymph, thereby stimulating the cochlea hair cells to
cause a hearing percept.
SUMMARY
[0009] In one aspect of the disclosed technology, a vibrator is
described. The vibrator comprises: a housing; a transducer
positioned within the housing such that there is a gap between the
transducer and housing; and an impulse force damper, disposed in
the gap between the housing and the transducer, configured to
mechanically isolate the transducer and the housing from each
other, and to minimize impulse forces applied to the
transducer.
[0010] In another aspect of the disclosed technology, a method for
making an impulse-force-resistant vibrator is described. The method
comprises: providing a vibrator including a transducer mounted in a
housing such that a gap exists between the transducer and the
housing; forming a first layer on a portion of one of the housing
and the transducer; and substantially filling the gap between the
first layer and the other of the housing and the transducer with a
second layer; and wherein substantially no adhesion is exhibited
between the second layer and one of the housing and the
transducer.
[0011] In a third aspect of the disclosed technology, a method of
damping an impulse force to which a vibrator for an auditory
prosthesis is susceptible, the vibrator including a housing, a
transducer mounted in the housing and a multilayer damper disposed
between the housing and the transducer, is described. The method
comprises: compressing the damper in response to the impulse force,
the compressing including: deforming at least one layer of the
damper so as to dissipate energy of the impulse force; and slipping
of at least one layer with respect to one of the housing and the
transducer, due to there being substantially no adhesion between
the at least one layer between and one of the housing and the
transducer. The damper comprises at least one layer that provides a
lack of adhesion between itself and one of the housing and the
transducer in order to achieve the slipping.
[0012] In another exemplary embodiment, there is a method of making
an impulse-force-resistant vibrator, the method comprising
providing a vibrator including a transducer mounted in a housing
such that a gap exists between the transducer and the housing,
forming a first layer on a portion of one of the housing and the
transducer, and substantially filling the gap between the first
layer and the other of the housing and the transducer with a second
layer, and wherein substantially no adhesion is exhibited between,
the first and second layers, or at least one of the first and
second layers and at least one of the housing and transducer.
[0013] In another exemplary embodiment of any one or more of the
methods detailed above or below, the forming includes coating the
portion of one of the housing and the transducer with an elastomer
substantially conforming to manufacturing tolerances of the surface
of the one of the housing and the transducer, and the substantially
filling includes injecting an uncured or semi-cured elastic
material into the gap via at least one of one or more openings or
more ducts in a mass component of the transducer. In another
exemplary embodiment of any one or more of the methods detailed
above or below, the method(s) further include curing the elastic
material. In another exemplary embodiment of any one or more of the
methods detailed above or below, the forming includes depositing
the first layer onto the portion of one of the housing and the
transducer so as to thereby substantially conform to manufacturing
tolerances thereof, and the substantially filling includes flowing
the second layer so as to thereby substantially conform to
manufacturing tolerances of the other of the housing and the
transducer.
[0014] In another exemplary embodiment of any one or more of the
methods detailed above or below, the forming of the first layer and
the substantially filling the gap with the second layer impose
substantially no static preload on the transducer. In another
exemplary embodiment of any one or more of the methods detailed
above or below, the vibrator is configured for incorporation in a
bone conduction device.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Exemplary embodiments of the present technology are best
understood from the following detailed description when read in
conjunction with the accompanying drawings. The accompanying
drawings, which are incorporated herein and form part of the
specification, illustrate exemplary embodiments of the present
disclosure and, together with the description, serve to explain
principles, aspects and features of the present disclosure, and
further serve to enable a person skilled in the relevant art to
make and use the present technology. It is emphasized that,
according to common practice, the various features of the drawings
are not to scale. On the contrary, the dimensions of the various
features are arbitrarily expanded or reduced for clarity. Common
numerical references represent like features/elements. Embodiments
of the present technology are described below with reference to the
attached drawings, in which:
[0016] FIG. 1A is a perspective view of an exemplary auditory
prosthesis, namely a percutaneous bone conduction device, in which
embodiments of the present technology may be implemented;
[0017] FIG. 1B is a perspective view of an exemplary auditory
prosthesis, namely a transcutaneous bone conduction device, in
which embodiments of the present technology may be implemented;
[0018] FIG. 1C is a schematic diagram illustrating an exemplary
active transcutaneous bone conduction device in which embodiments
of the present technology may be implemented;
[0019] FIG. 2A is a schematic cross-sectional simplified view of an
exemplary vibrator that may be implemented in the auditory
prostheses of FIGS. 1A-1C;
[0020] FIG. 2B is a schematic cross-sectional simplified view of an
exemplary vibrator having an impulse force damper that may be
implemented in the auditory prostheses of FIGS. 1A-1C;
[0021] FIG. 3A is a schematic side view of a vibrator having
impulse force dampers and dual counter-masses, in accordance with
exemplary embodiments of the present technology;
[0022] FIG. 3B depicts a vibrator having various multi-layer
arrangements of impulse force dampers, in accordance with
embodiments of the present technology;
[0023] FIG. 3C depicts a vibrator having various multi-layer
arrangements of impulse force dampers, in accordance with
embodiments of the present technology;
[0024] FIG. 3D depicts a vibrator having various multi-layer
arrangements of impulse force dampers, in accordance with
embodiments of the present technology;
[0025] FIG. 4 is a graph illustrating the effects of using impulse
force dampers in a auditory prostheses, in accordance with
embodiments of the present technology; and
[0026] FIG. 5 is a flowchart depicting steps by which an
impulse-force-resistant vibrator can be made, in accordance with
embodiments of the present technology.
DETAILED DESCRIPTION
[0027] Embodiments of the present technology are generally directed
to a medical device having an impact force-resistant component. In
some embodiments, the component is a vibrator. The component has a
housing in which a functional element is disposed. There is a gap
between the housing and functional element, and the functional
element may have some freedom of movement inside the housing. An
impulse force damper is disposed in, and in at least some exemplary
embodiments, fills, the gap between the functional element and the
housing so as to substantially absorb impulse forces thereby
minimizing potential damage to the functional element Impulse
forces may be created, for example, by rapid acceleration or
deceleration of the component and/or by physical contact of the
functional element with the component housing. Impulse forces can
be generated by external sources, such as, for example, an impulse
force applied to an external surface of the housing of the medical
device or an impulse force applied to the recipient's head. Impulse
forces can also originate from internal sources, such as, for
example, movement of the functional component within the housing,
or inertia of a moveable portion of the functional component. In
those applications in which, when operating, the functional element
translates, rotates, changes dimensions, or otherwise moves, the
impulse force damper substantially mechanically isolates the
functional element from the housing nor does it load the functional
element so as to minimize changes in the performance of the
functional element due to the presence of the impulse force
damper.
[0028] In specific disclosed embodiments, the impulse force damper
includes two layers of material: an isolation layer adjacent the
functional element or housing, and a force dissipation layer
disposed between the isolation layer and the other of the
functional element or housing. The isolation layer minimizes
adhesion of the force dissipation layer to the adjacent element or
housing on the opposing side of the isolation layer. This prevents
the housing from altering the physical movement of the functional
element during its operation. The isolation layer prevents the
housing from altering the physical movement functional element
during operation. In other words, the isolation layer mechanically
isolates the housing from the functional element so that they do
not become one element due to their respective connections to the
impulse force damper. The force dissipation layer absorbs an
impulse force by deforming to absorb the energy in the functional
element as it travels toward the housing. For example, in some
embodiments the force dissipation layer is elastic. As such,
deformation of this layer results in a change in the dimensions of
the layer to accommodate the closing gap between the functional
element and housing. That is, the force dissipation layer deforms
such that a portion of the force dissipation layer moves to/from
other regions of the gap or to/from the gap as the dimensions of
the gap change.
[0029] In some disclosed embodiments, the medical device is an
auditory prosthesis, such as a bone conduction device or a middle
ear implant, both of which convert received sound signals into
mechanical vibrational forces for delivery to a recipient of the
prosthesis. One component of such auditory prostheses is commonly
referred to as a vibrator. Disposed in the housing of the vibrator
are a variety of functional elements one of which is a transducer.
The transducer may be any transducer now or later developed, such
as an electro-acoustic transducer or an electro-mechanical
transducer. In some embodiments, the transducer comprises a
piezoelectric element. The transducer typically also includes one
or more mass components, and a coupling configured to attach the
vibrator to another component or the recipient. Movement of the
piezoelectric element induces the mass components to vibrate, which
in turn generates mechanical forces. The coupling transfers
mechanical forces generated by the transducer to the recipient.
[0030] In certain embodiments, the impulse force damper includes a
damping layer that absorbs impulse forces and an isolation layer
that creates slip between itself and one of the housing or the
transducer. In some embodiments, the isolation layer comprises
silicone (i.e., a silicone layer). The isolation layer allows slip
between itself and one of the housing or transducer, depending on
the position of the isolation layer, so as to mechanically isolate
the transducer from the housing. In some disclosed embodiments, the
impulse force damper provides isolation between the housing and
transducer including a piezoelectric element so as to protect the
piezoelectric element against impulse forces while maintaining the
transducer output. In exemplary embodiments, the impulse force
damper protects the piezoelectric element against external and
internal impulse forces without altering a frequency response of
the transducer. According to these embodiments, the impulse force
damper does not affect the output curve or resonance frequencies of
the transducer.
[0031] Vibrators and auditory prostheses having impulse force
dampers in accordance with certain embodiments of the present
technology may have the utilitarian feature, in at least some
embodiments, of delivering initial resonance frequency location, or
a resonance frequency location substantially the same as the
initial resonance frequency location, and output force levels
(OFLs) of the designed configurations without being adversely
influenced by impulse shock forces. Some embodiments of the impulse
force damper protects the transducer from impulse forces without
substantially altering the transfer function of the transducer.
[0032] As noted above, bone conduction devices have been found
suitable to treat a variety of types of hearing loss and may be
suitable for individuals who cannot derive sufficient benefit from
other types of auditory prostheses. FIGS. 1A and 1B are perspective
views of bone conduction devices 100 in which embodiments of the
present technology may be implemented. FIG. 1C is a schematic
diagram illustrating an active transcutaneous bone conduction
device 100C in which embodiments of the disclosed technology may be
implemented. As shown in FIGS. 1A and 1B, the recipient has an
outer ear 101, a middle ear 102 and an inner ear 103.
[0033] 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 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
tiny hair cells (not shown) that line the inside of cochlea 115.
Activation of the 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. 1A also illustrates the positioning of a bone
conduction device 100A relative to outer ear 101, middle ear 102
and inner ear 103 of a recipient of the device. As shown, exemplary
bone conduction device 100A is a percutaneous bone conduction
device positioned behind outer ear 101 of the recipient. In the
embodiment illustrated in FIG. 1A, bone conduction device 100A
comprises a vibrator 125 and a sound input element 126 positioned
in, on or coupled to vibrator 125. Sound input element 126 is
configured to receive sound signals and may comprise, for example,
a microphone, telecoil, etc. Sound input element 126 may also be a
component that receives an electronic signal indicative of sound,
such as, for example, from an external audio device. Typically,
vibrator 125 comprises a sound processor, a transducer, and various
other electronic circuits/components. Sound signals received by
sound input element 126 are converted to electrical signals which
are processed by the sound processor to generate drive signals
which cause the actuator to vibrate.
[0035] Bone conduction device 100A further includes a vibratory
coupling 160 that extends from the housing of vibrator 125 to
releasably connect to a percutaneous abutment fixed to the
recipient's skull bone 136. For example, with reference to the
embodiment shown in FIG. 1A, coupling 160 may be connected to a
percutaneous abutment implanted under the skin 132 of the
recipient, within muscle tissue 134 and/or fat tissue 128. In the
specific embodiment of FIG. 1A, coupling 160 can be attached to an
anchor system implanted in the recipient. Such an anchor system can
comprise a percutaneous abutment fixed to the recipient's skull
bone 136. The abutment can extend from bone 136 through muscle 134,
fat 128 and skin 132 so that coupling 160 may be attached thereto.
Such a percutaneous abutment provides an attachment location for
coupling 160 that facilitates efficient transmission of mechanical
vibrational forces generated by percutaneous bone conduction device
100A.
[0036] FIG. 1B is a perspective view of another bone conduction
device 100B in which embodiments of the present technology may be
implemented. Bone conduction device 100B is a transcutaneous bone
conduction device comprising external and implantable components.
Bone conduction device 100B includes a vibrator 125 and a sound
input element 126 to receive sound signals. In exemplary
embodiments, sound input element 126 is located, for example, on or
in vibrator 125, or it may be subcutaneously implanted in the
recipient.
[0037] In the arrangement illustrated in FIG. 1B, bone conduction
device 100B is a passive transcutaneous bone conduction device due
to all active components being external to the recipient. In such
an arrangement, vibrator 125 is located behind outer ear 101, and
the vibrations are transcutaneously transferred to the skull via a
pair of magnetic plates 149, 150. External magnetic plate 149 is
connected to vibrator 125 via coupling 160. During normal
operations, external magnetic plate 149 vibrates with the actuator.
Such vibrations are transcutaneously transferred to internal
magnetic plate 150 which is magnetically coupled to external
magnetic plate 149. The vibrations are transferred to skull 136 via
bone fixture 162.
[0038] It is to be appreciated that transcutaneous bone conduction
device 100B may be an active transcutaneous bone conduction device
in which at least one active component is implanted in the
recipient. In one such arrangement, a signal receiver and/or
various other electronic circuits/devices are implantable. An
example of such an active transcutaneous bone conduction device is
described below with reference to FIG. 1C. It is also to be
appreciated that embodiments of the present technology may be
implemented with other types of auditory prostheses including
implantable middle-ear mechanical stimulation devices (not shown).
Typically, implantable middle-ear mechanical stimulation devices
are implantable within middle ear 102 and are configured to deliver
mechanical forces to ossicles 111 or cochlea 115. Such mechanical
forces directly or indirectly cause fluid motion in the cochlea
which, in turn, cause the generation of nerve impulses which travel
through the spiral ganglion cells and auditory nerve 116 to the
brain (not shown), where they are perceived as sound.
[0039] FIG. 1C depicts an exemplary embodiment of a transcutaneous
bone conduction device 100C according to another embodiment of the
present technology that includes an external device 140 and an
implantable component 151. The transcutaneous bone conduction
device 100C of FIG. 1C is an active transcutaneous bone conduction
device in that the vibrating actuator 152 is located in the
implantable component 151. Specifically, a vibratory element in the
form of vibrating actuator 152 is located in housing 154 of the
implantable component 151. In exemplary embodiments, much like
vibrators 300A-D described below with respect to FIGS. 3A-3D, the
vibrating actuator 152 is a device that converts electrical signals
into vibration.
[0040] External component 140 includes a sound input element 126
that converts sound into electrical signals. Specifically, the
transcutaneous bone conduction device 100C provides these
electrical signals to vibrating actuator 152, or to a sound
processor (not shown) that processes the electrical signals, and
then provides those processed signals to the implantable component
151 through the skin 132 of the recipient via a magnetic inductance
link. In this regard, a transmitter coil 142 of the external
component 140 transmits these signals to implanted receiver coil
156 located in housing 158 of the implantable component 151.
Components (not shown) in the housing 158, such as, for example, a
signal generator or an implanted sound processor, then generate
electrical signals to be delivered to vibrating actuator 152 via
electrical lead assembly 161. The vibrating actuator 152 converts
the electrical signals into vibrations.
[0041] The vibrating actuator 152 is mechanically coupled to the
housing 154. Housing 154 and vibrating actuator 152 collectively
form a vibrating element. The housing 154 is substantially rigidly
attached to bone fixture 164. In this regard, housing 154 includes
through hole 162 that is contoured to the outer contours of the
bone fixture 164. Housing screw 146 is used to secure housing 154
to bone fixture 164. The portions of housing screw 146 that
interface with the bone fixture 164 substantially correspond to the
abutment screw detailed below, thus permitting housing screw 146 to
readily fit into an existing bone fixture used in a percutaneous
bone conduction device (or an existing passive bone conduction
device such as that detailed above). In an exemplary embodiment,
housing screw 146 is configured so that the same tools and
procedures that are used to install and/or remove an abutment screw
from bone fixture 164 can be used to install and/or remove housing
screw 146 from the bone fixture 164.
[0042] FIG. 2A is a simplified block diagram of an exemplary
auditory prosthesis vibrator 200 representing, for example,
vibrators 125 described above with reference to FIGS. 1A and 1B and
vibrating actuator 152 described above with reference to FIG. 1C.
Vibrator 200 (or vibrating element, "vibrator" herein) includes a
housing 208, a vibrating transducer 202 ("transducer" herein,
sometimes referred to as a transducer module), a coupling apparatus
160 that is mechanically connected to vibrating transducer 202 and
extends from housing 208. Transducer 202 and coupling apparatus 160
are suspended in housing 208 by flat spring 204. In an exemplary
embodiment, flat spring 204 is connected to coupling apparatus 160,
and transducer 202 is supported by coupling apparatus 160. The
configuration of the opposing distal end of coupling apparatus 160
varies depending on whether vibrator 202 is a component of an
active transcutaneous bone conduction device, such as the devices
shown in FIGS. 3A-3D, or passive transcutaneous bone conduction
device.
[0043] As shown in FIG. 2A, there is void, space or gap ("gap" 206
herein) between transducer 202 and housing 208 resulting from the
suspension of transducer 202 by flat spring 204 inside housing 208.
At times vibrator 200 may be subjected to a sudden increase or
decrease in velocity resulting from, for example, a shock or blow
to the component and/or to the recipient. When this occurs,
transducer 202 may experience rapid acceleration or deceleration
and/or may contact interior surface 214 of housing 208 with a force
referred to herein as an impulse force. Such an impulse force may
be sufficient to damage the transducer. Due to the configuration of
vibrator 200, impulse forces which are more likely to cause damage
to transducer 202 are those forces which have a vector component
that is parallel to vibration axis 210 since transducer 202 is
provided freedom of movement along axis 210. That is, an impulse
force may be applied to top surface 212 of transducer 202 when
transducer 202 travels through gap 206 to, perhaps, strike housing
interior surface 214. FIG. 2B depicts the same simplified block
diagram of auditory prosthesis vibrator 200 as shown in FIG. 2A.
However, in FIG. 2B, vibrator 200 includes an impulse force damper
216 disposed between transducer top surface 212 and housing
interior surface 214. Impulse force damper 216, in at least some
exemplary embodiments, fills gap 206, as shown in FIG. 2B. Impulse
force damper 216 does not adhere to at least one of the adjacent
transducer and housing interior surfaces 212 and 214, respectively.
Such mechanical isolation prevents housing 208 from interfering
with the operational performance of transducer 202. Impulse force
damper 216 substantially absorbs impulse forces created by physical
movement of transducer 202 along vibration axis 210.
[0044] FIGS. 3A-3D are block diagrams of a vibrator 200, referred
to herein as vibrators 300A-300D, respectively. Various embodiments
of impulse force damper 216 are implemented in vibrators 300A-300D,
which are described with reference to the bone conduction devices
illustrated in FIGS. 1A-1C. For brevity, only differences presented
in FIGS. 3A-3D are described below.
[0045] Referring to FIG. 3A, vibrator 300A has a transducer 302
comprised of a piezoelectric element 301 attached to two masses
307A, 307B, by extension arms 304A, 304B, respectively. As shown in
the exemplary embodiments of FIGS. 3A-3D, the piezoelectric element
301 can include piezoelectric extension arms 304A and 304B (i.e.,
extension arms 304A, 304B are piezoelectric elements and function
collectively, with the piezoelectric element 301, as a single
piezoelectric element). A piezoelectric element converts an
electrical signal applied thereto into a mechanical deformation
(i.e., expansion or contraction) of the piezoelectric element. The
extent of deformation of the piezoelectric element in response to a
given applied electrical signal depends on the material properties
of the element, the orientation of the electric field with respect
to the polarization direction of the element, the geometry of the
element, etc., as is well known in the art.
[0046] Each mass 307 is formed of material such as tungsten,
tungsten alloy, brass, etc., and may have a variety of shapes.
Additionally, the shape, size, configuration, orientation, etc., of
each mass 307 may be selected to optimize the transmission of the
mechanical force from piezoelectric transducer 302 to the
recipient's skull and to optimize the frequency response of the
transducer. In certain embodiments, the size and shape of each mass
307 is chosen to ensure that there sufficient mechanical force is
generated and to optimize the response of the transducer 302.
[0047] In specific embodiments, masses 307 have a weight between
approximately 1 g and approximately 50 g. Furthermore, the material
forming masses 307 may have a density, e.g., between approximately
2000 kg/m3 and approximately 22000 kg/m3. As shown, piezoelectric
element 301 is also attached to coupling 160 which is utilized to
transfer the mechanical force generated by the transducer to the
recipient's skull.
[0048] Transducer 302 is suspended in housing 125 such that there
is a gap 306 between housing 308 and transducer 302. That is,
housing interior surface 314 and the surface 312 of the masses are
in spaced juxtaposition to define a gap 306A-306D. As noted, gaps
306 allows for the vibration of transducer 302 in vibration axis
310. In the embodiment illustrated in FIG. 3A, impulse force
dampers 316A-D are disposed between housing interior surface 314
and the adjacent surfaces 312 of masses 307 to substantially fill
their respective gap 306 between housing interior surface 314 and
juxtaposed mass surface 312. In at least some embodiments, impulse
force dampers 316 prevent the rapid acceleration and deceleration
of masses 307. Such movement may cause a significant impulse force
to be applied to piezoelectric element 301 given the size of masses
307 and length of extension arms 304. For ease of description,
impulse force damper 316A will be described below. With the
exceptions noted below, the description of impulse force damper
316A applies to impulse force dampers 316B-D.
[0049] In certain embodiments, damper 316A includes at least two
layers, an elastic force dissipation layer 318A and an isolation
layer 320A. Force dissipation layer 318A substantially dissipates
the kinetic energy in the moving mass 307A thereby preventing the
mass from experiencing sudden acceleration or deceleration which
would cause piezoelectric element 301 from experiencing a
potentially damaging impulse force. Isolation layer 320A is
disposed between force dissipation layer 318A and transducer mass
307A. In some embodiments, isolation layer 320A is formed from a
silicone elastomer. In the same or other embodiments, force
dissipation layer 318A is substantially elastic shock absorbing
layer formed of a soft and elastic material such as a cured liquid
silicone rubber material. As noted, force dissipation layer 318A
deforms as mass 307A travels toward the housing. This deformation
absorbs energy, causing a decrease in the rate at which the
transducer travels and limits the amount of force transmitted to
the piezoelectric elements or the mass elements. In some
embodiments, frequency response and output of vibrator 300A is
maintained because housing 308 and mass 307 are decoupled and
prevented from adhering to each other. For example, as shown in the
exemplary embodiment of FIG. 3A, the isolation layer 320A disposed
between the force dissipation layer 318A and the housing interior
surface 314 decouples mass 307A from housing 308 and prevents mass
307A from adhering to housing 308.
[0050] Force dissipation layer 318A is formed of material(s)
configured to exhibit sufficiently low stiffness and/or sufficient
elasticity so as to flex or deform in response to a compressive
force caused by transducer mass 307A traveling toward housing
surface 314, thereby reducing the rate at which gap 306A decreases.
Elastic materials strain when stretched and return to their
original state relatively quickly once the stress is removed. In
certain embodiments, force dissipation layer 318A is an elastic
material made from one or more of a soft silicone type material, a
foam material, and a rubber material.
[0051] Thus, exemplary force damper 316A is configured to achieve
impulse force dissipation through a combination of deformation of
an elastic material exhibiting sufficiently low stiffness and shear
damping via substantial gross slip along the interface where a
surface of damper 316A abuts an adjacent layer or surface. In one
embodiment, impulse force dissipation layer 318A comprises a cured
liquid silicone rubber.
[0052] Isolation layer 320A is disposed between force dissipation
layer 318A and mass 307A to prevent adhesion of the force
dissipation layer to mass surface 312. Isolation layer 320A can be
configured to achieve this by preventing adhesion between itself
and mass 307A. In some embodiments, the force dissipation and
isolation layers are configured to exhibit substantially no
adhesion between each other.
[0053] Impulse force damper 316A comprises a relatively thin
isolation layer 320A and a relatively thick impulse force
dissipation layer 318A. It should be appreciated that the absolute
and relative thicknesses of force dissipation layer 318A and
isolation layer 320A depicted in FIG. 3A is for ease of
illustration, and is not intended to illustrate specific or
relative dimensions. In certain embodiments, isolation layer 320A
has a thickness between 0.1 mm and 0.6 mm and impulse force damper
316A has an overall thickness of between 0.2 mm and 10 mm. Force
dissipation layer 318A can have a thickness of between 0.4 mm to
0.9 mm. Other size ranges, larger or smaller, than the exemplary
size ranges described herein, are possible depending on the
dimensions of the vibrator and the gap. In alternative embodiments,
layers 320A and 318A have substantially the same thickness.
[0054] In some embodiments isolation layer 320 is a relatively thin
film or sheet arranged on either side of mass components 307 and
impulse force dissipation layer 318 is a relatively thicker shock
absorbing/damping material arranged between isolation layer 320 and
housing 125. In certain embodiments, the isolation layer 320 can
comprise a cured silicone elastomer having a thickness of less than
about 70 micrometers (.mu.m). The force dissipation layer 318 is
configured to deform laterally with respect to a surface of the
transducer (such as a surface 312 of mass component 307) and an
opposing surface 314 of housing 308 in order to dissipate an
impulse force applied to the vibrator. In embodiments, impulse
force dissipation layer 318 can comprise a cured silicone
rubber.
[0055] In certain embodiments, isolation layer 320A comprises a
material having one of more of the following: an American Society
for Testing and Materials (ASTM) technical standard D2240 Durometer
Type A scale value of about 50; a Tensile Strength of about 1450
psi (pounds per square inch); an Elongation of about 1000%; a Tear
Strength (Die B) of about 250 ppi (pounds per inch); a Stress @200%
Strain of about 300 psi; and a Specific Gravity of about 1.16. A
commercially available example of such a material is Model No. MED
49-01 (a type of silicone elastomer) manufactured by NUSIL.RTM.
Technology, LLC, in a cured state, which is available in sheets of
about 0.002 inches thick.
[0056] In certain embodiments, impulse force dissipation layer 318A
comprises a material having one of more of the following: an ASTM
technical standard D2240 Durometer Type OO scale value less than or
equal to about 40; a Tensile Strength of about 325 psi; an
Elongation of about 1075%; a Tear Strength of about 60 ppi; a
Stress @100% Strain of about 10 psi; a Stress @300% Strain of about
30 psi; and a Stress @500% Strain of about 65 psi. A commercially
available example of such a material is Model No. MED 82-50 1 0-02
(a type of liquid silicone rubber) manufactured by NUSIL.RTM.
Technology, LLC, in a cured state.
[0057] Thus, in the embodiment of FIG. 3A, force dissipation layer
318A is configured to exhibit non-negligible adhesion to housing
surface 314 and substantially no adhesion to isolation layer 320A.
This enables impulse force damper 316A to dissipate energy through
a combination of deformation and shear damping along the interface
between with isolation layer 320A. Shear damping refers to the
lateral sliding or slipping of the layers 318A and 320A, which is
possible due to lack of adhesion between the layers.
[0058] In certain embodiments, isolation layer 320A is configured
to exhibit substantially no adhesion with respect to an adjacent
surface of impulse force dissipation layer 318A so as to allow
gross slip via at least some shear damping along one or more of an
interface between: dissipation layer 318A and isolation layer 320A.
For example, isolation layer 320A can be configured to act as an
anti-adhesive or lubricant with respect to dissipation layer 318A.
Shear damping along an interface between dissipation layer 318A and
isolation layer 320A can be explained by considering the behavior
of two adjacent surfaces that are in contact with each other. A
clamping force may exist between these two surfaces. Such a
clamping force can result from externally applied loads, or from a
mating or press fit that produces an interface common to the two
parts. If an additional exciting force is gradually imposed, the
two parts may initially react as a single elastic body such that
there is shear on the interface, but not enough to produce relative
slip at any point. As the force increases in magnitude to the
extent that the force constitutes application of an impulse force,
the resulting shearing traction at some places on the interface can
exceed the limiting value permitted by the friction characteristics
of the two mating surfaces (e.g., a surface of isolation layer 320A
and an adjacent surface dissipation layer 318A). According to the
embodiments described herein, isolation layer 320A of impulse force
damper 316A exhibits substantially no adhesion to dissipation layer
318A such that the limiting value and shearing traction are
sufficiently low so as to allow gross slip to occur along the
interface where dissipation layer 318A and isolation layer 320A
mate with each other. In regions where a surface of impulse force
damper 316A mates with mass component 307A, 307B or housing 308,
microscopic slip of adjacent points on opposite sides of the
interface can occur. In an alternative embodiment, there is slip
between the two layers of the impulse force damper 316A. According
to this embodiment, there is slip between force dissipation layer
318A and isolation layer 320A. In an exemplary embodiment, the
slipped region extends substantially over the entire interface
between layers 318A and 320A so that gross slip can occur. In some
embodiments, slip occurs between isolation layer 320A and one of
the interior housing surface 314 or the mass 307 depending on which
is in contact with isolation layer 320A. Subsequent application of
a tangential force can produce slip over a portion of the interface
even if a peak tangential force is not great enough to affect gross
slip or sliding along the interface. In certain embodiments,
isolation layer 320A can comprise a relatively thin (with respect
to layer 318A) foil, sheet, or film of silicone elastomer coating a
surface of a portion of a transducer, such as a region or surface
of mass component 307. For example, isolation layer 320A can be a
cured silicone elastomer applied to mass components 307 so as to
allow gross slip between impulse force dissipation layer 318A and
isolation layer 320A. In some embodiments, gross slip occurs
between the isolation layer 320A and the housing 308 or mass 307,
depending on which one the isolation layer 320A is in contact with.
In an alternative embodiment, slip occurs between force dissipation
layer 318A and the isolation layer 320A.
[0059] As seen in FIGS. 3A-D, embodiments of impulse force dampers
comprise varying arrangements of layers 320 and 318 in which
isolation layer 320 is in contact with either housing surface 314
or transducer mass surface 312, and force dissipation layer 318 is
in contact with the other surface. In certain embodiments, layers
320 and 318 are arranged and configured so that the layers
substantially conform to manufacturing tolerances of a respective,
abutting housing interior surface 314 and mass surface 312. In FIG.
3B, isolation layers 320A, 320B are applied to or interface with
housing interior surfaces 314 and force dissipation layers 318A,
318B are applied to or interface with mass surfaces 312. Impulse
force dampers 316C, 316D are configured as described above with
reference to FIG. 3A. In FIG. 3C, all four impulse force dampers
316A-D are configured the same as impulse force dampers 316A, 316B
of FIG. 3B. In FIG. 3D, impulse force dampers 316A-D each have two
isolation layers 320 applied to or interfacing with housing
interior surface 314 and mass surface 312, with the respective
force dissipation layer 318 disposed between the two isolation
layers.
[0060] According to embodiments, the vibrators shown in FIGS. 3A-D
can be used in auditory prostheses, such as, but not limited to,
active transcutaneous bone conduction devices. The vibrators 300A-D
can be used for other bone conduction devices. For example, the
vibrators shown in FIGS. 3A-D with an impulse force damper 316
comprising a force dissipation layer 318 and an isolation layer 320
can be used in other types of bone conduction devices in a similar
manner to absorb impulse forces without substantially altering the
frequency response of the vibrator. In certain embodiments such
vibrators are configured for incorporation in bone conduction
devices. For example, the vibrators described below with reference
to FIGS. 3A-D can be implemented in transcutaneous bone conduction
devices 100B and 100C, percutaneous bone conduction devices 100A,
and in subcutaneous bone conduction devices.
[0061] Each layer of the exemplary impulse force dampers 316A-D are
shown in FIGS. 3A-3D as having a rectangular shape. It should be
understood that this is for ease of illustration, and that the
shape of each layer depends on the material used, the properties of
that material, and the manner in which the layers are applied.
[0062] FIG. 4 is a graph illustrating the operational performance
of a vibrator implementing different embodiments of impulse force
damper 216. Specifically, FIG. 4 illustrates the relationship
between transducer output force level (OFL) 410 for a given
operational frequency response 420 of the transducer. Because bone
conduction devices deliver sound as vibrations in skull bone 136,
FIG. 4 plots OFL 410 as a measure of vibration in relation to
sound. A decibel (dB) in relation to 1 micronewton (.mu.N) is a
measure of the vibrational force produced by the device at
different frequencies 420, which are expressed in Hertz (Hz).
[0063] Waveform 430 shows the OFLs across frequency range 420 for a
vibrator of a transducer which does not implement an impulse force
damper as described herein. Waveform 450 shows the OFLs across
frequency range 420 for the same vibrator of the same transducer
which implements an embodiment of the impulse force damper
described herein. As shown in FIG. 4, at most frequencies 420 the
OFL 410 of a vibrator implementing an impulse force damper is the
same or substantially the same as the OFL of a vibrator which does
not implement an impulse force damper. The similarity of waveforms
430 and 450 illustrates that the impulse force damper does not load
the transducer, and provides sufficient mechanical isolation of the
housing to prevent the housing from loading the transducer. The
similarity of waveforms 430 and 450 shows that the impulse force
damper with an isolation layer does not substantially affect the
frequency response of the vibrator, and that the locations of the
respective resonance peaks 460 and 470 are almost identical. FIG. 4
illustrates that the performance of the vibrator with and without
the impulse force damper with the isolation layer is substantially
similar. This is achieved in part because in a quiescent state, the
impulse force damper with the isolation layer imposes substantially
no static preload on the transducer. As shown in FIG. 4, the
impulse force damper is configured such that it causes a
substantially insignificant effect on the frequency response of the
vibrator. This is utilitarian in at least some embodiments because
the impulse force damper helps to absorb impulse forces without
affecting performance, thus ensuring that a recipient receives the
appropriate stimulation as designed.
[0064] More specifically, waveform 450 reflects a limited effect on
OFL 410 at lower values of frequencies 420, including only slight
damping (magnitude attenuation) and shifting of first resonance
peak 460, and substantially no effect at higher frequencies 420, as
evidenced by the lack of any amplitude change. In particular,
frequency response curve 450 shows that the amplitude of first
resonance peak 460 is slightly damped by about 2-3 dBs. Frequency
response curve 450 also shows first resonance peak 460 for a
vibrator with an impulse force damper comprising both layers is
shifted upwards by around 100 Hz from approximately 700 Hz to
approximately 800 Hz.
[0065] Waveform 440 shows the OFLs across frequency range 420 for a
vibrator of a transducer which implements the force dissipation
layer of the impulse force damper, and not the isolation layer. As
shown in FIG. 4, waveform 440 is offset from waveform 430,
resulting in the OFL of a vibrator implementing just the force
dissipation layer being different than the OFL of a vibrator
without an impulse force damper, at least for a substantial portion
of frequency range 420. This altering of the OFL at certain
frequencies is due to the load placed on the transducer by the
housing due to the reduced mechanical isolation which would
otherwise be provided by the absent isolation layer. The additional
loading occurs because the housing and mass effectively become a
single element due to contact with the dissipation layer, and move
as a unitary mass. This added mass of the housing on the transducer
significantly alters the performance of the transducer. This
altered performance of the transducer is undesirable as it results
in inappropriate stimulation signals being delivered to the
recipient, which can have the undesirable effects of altering
output quality or preventing a hearing percept from being
generated.
[0066] With continued reference to FIG. 4, frequency response curve
440 of a vibrator having an impulse force damper as described
herein, and lacking an isolation layer can exhibit a relatively
large effect on OFL 410. As shown the first peak 460 of such a
vibrator can be damped significantly (e.g., by more than 10 dBs)
and can be shifted upwards or downwards by as much as +-2000 Hz.
Such a large shift of first resonance peak 460 may cause a vibrator
to exhibit harmonic distortion in excess of 400 Hz, making the
vibrator unsuitable for incorporation into auditory prosthesis.
[0067] While various impulse force damper configurations and
arrangements may adequately protect a vibratory actuator/transducer
from shock forces, configurations affecting OFL 410 enough to shift
resonance peaks 460 or 470 to different frequencies 420 may not be
suitable for use in transducers for auditory prostheses. Relative
to a quiescent state in which no damper is mounted vis-a-vis the
transducer, a damper can be described as applying a preload to a
transducer if the mounted damper has the effect of applying a
static force (a bias force) to the transducer, however small the
preload might be. For example, a layer of damping material injected
in its uncured state into a gap between a mass (attached to a
transducer) and the housing so as to fill the might preload the
transducer if the damping material expands when it transitions into
its cured state. As another example, a vibrator relying solely upon
a mechanical element such as spring to dampen impulse forces may
preload a transducer or a mass component to the extent that OFL 410
is unduly affected. Impulse force dampers that have a minimal,
limited effect on a transducer's OFL 410 while also dissipating
impulse forces so as to substantially isolate a transducer from the
impulse force are more suitable for auditory prostheses such as
bone conduction devices Impulse force dampers configured to
dissipate an impulse force via deformation thereof thereby
preventing damage to transducer while also having minimal shifting
or damping effects on resonance peaks 460 and 470 are suitable
impulse-force-resistant transducers for incorporation in an
auditory prosthesis. In contrast, impulse force dampers applying
sufficient preload to a transducer or mass component affects OFL
410 in terms of the amplitudes of resonance peaks 460 or 470 being
altered and/or resonance peaks 460 or 470 being shifted to
different frequencies 420. Such alterations and shifts can make
such impulse force dampers less desirable for use in bone
conduction devices.
[0068] FIG. 5 is a flowchart depicting steps by which an
impulse-force-resistant vibrator can be made. The flowchart
depicted in FIG. 5 is described with reference to the embodiments
described above. However, FIG. 5 is not limited to those example
embodiments. The steps of methods for making
impulse-force-resistant vibrator do not necessarily have to occur
in the order shown in FIG. 5 and described below. According to
embodiments, some of the steps shown in FIG. 5 are optional.
Optional steps are indicated in the flowchart by dashed lines (see,
e.g., steps 504, 506, and 514).
[0069] The method begins in step 502 when a vibrator including a
transducer with preassembled mass components is provided. After the
vibrator is provided, the method optionally proceeds to step 504
where the masses are connected to a vibratory actuator of the
transducer, or alternatively to step 506 when no mass components
are to be included. In optional step 504, one or more mass
components are attached to a vibratory actuator. In certain
embodiments this step comprises attaching a piezoelectric element
to at least one mass component. By completing step 504, embodiments
such as those described above can be implemented whereby the
transducer comprises single or dual mass components attached to a
piezoelectric actuator. In embodiments, step 504 can comprise
connecting one or more mass components to piezoelectric
elements.
[0070] After the mass components are connected to the vibratory
actuator (if desired), the method optionally proceeds to step 506
where the transducer is attached to a supporting member, or
alternatively to step 508 when the provided transducer is already
attached or mounted to the supporting member. In embodiments,
optional step 506 comprises mounting the transducer or actuator to
a coupling of an anchor system such as those described above with
reference to FIGS. 1A-1C. In an embodiment, step 506 can comprise
attaching the transducer structure with its piezoelectric elements
and mass components to the supporting member. After the transducer
is optionally attached to a supporting member, flow proceeds to
step 508. In step 508, the transducer provided in step 502 is
suspended or mounted within a first portion of a housing so that
gaps are between the juxtaposed transducer and surfaces of the
first portion of the housing. In embodiments, step 506 comprises
positioning the transducer such that there is a gap between
internal surfaces of the first portion of the housing and the
transducer. In an embodiment, step 508 can comprise mounting the
transducer within a bottom portion of a housing so that gaps are
between the transducer and the bottom portion of the housing.
[0071] In step 510, a first layer is formed on one of a surface of
the housing and the transducer. Embodiments of this step can
comprise depositing the first layer of the impulse force damper as
an isolation layer via spray, sputter, or vapor deposition onto a
region of one of the housing and the transducer. This step forms
the first layer such that it substantially conforms to
manufacturing tolerances of the surface to which it is applied.
Embodiments such as those depicted herein can implemented by an
alternative implementation of step 510 that forms dual isolation
layers of the damper on surfaces of the housing and the transducer.
Embodiments can include applying the first layer as a film, foil,
or other suitable coating onto target surface(s) and region(s) of
the housing and/or transducer. Regardless of the coating and
application technique employed to implement step 510, the first
layer substantially conforms to manufacturing tolerances of target
surface(s) and region(s). It should be appreciated that step 510
may be performed prior to the assembly of the vibrator in the prior
steps. In embodiments, step 510 comprises positioning the isolation
layer on one of an internal surface of the housing and a surface of
the mass component(s). In an alternative embodiment, step 510
comprises positioning the force dissipation layer on one of an
internal surface of the housing and a surface of the mass
component(s). This step can comprise injecting one of the force
dissipation layer or the isolation layer through opening(s) in the
mass component(s) onto an interior surface of the bottom portion of
the housing. In additional or alternative embodiments, step 510 can
comprise forming one of the force dissipation layer or the
isolation layer directly onto a surface the mass component(s).
After the first layer is formed, flow proceeds to step 512.
[0072] In step 512, the remainder of the gap between the first
layer and an opposing surface of the other of the housing or the
transducer are substantially filled with a second layer of the
impulse damper. In an embodiment, when step 510 placed the force
dissipation layer on the mass component(s), step 512 comprises
positioning the isolation layer on the force dissipation layer.
According to embodiments, step 512 can comprise injecting a shock
absorbing elastic material such as, but not limited to, an uncured
or semi-cured gel into an opening in the transducer, such as, for
example, via ducts in the mass component(s). This step can comprise
injecting one of the force dissipation layer or the isolation layer
through opening(s) in the mass component(s) into the remainder of
the gap between an interior surface of the bottom portion of the
housing and the mass component(s). For example, step 512 can
comprise injecting an uncured or semi-cured elastic silicone gel
into a gap corresponding to the region via opening(s) and/or
duct(s) in the transducer. In certain embodiments the openings
and/or ducts have diameters of approximately 1.2 mm. This step can
comprise flowing the second layer onto the opposing surface of the
other of the housing or the transducer such that the second layer
conforms to manufacturing tolerances of the surface. After the gap
is substantially filled, flow optionally proceeds to step 514 when
an uncured or semi-cured material is used.
[0073] In optional step 514, any uncured or semi-cured material
used for the second layer in step 512 is cured as needed and then
flow proceeds to step 516. After curing in step 514, the impulse
force damper exhibits sufficient elastic properties (i.e.,
elasticity) so as to dissipate an impulse force via deformation
thereof thereby substantially isolating a vibratory
actuator/transducer from the impulse force.
[0074] In step 516, a second portion of housing is attached to the
first portion of the housing from step 508 and the housing is
sealed. In certain embodiments, step 516 can comprise sealing
opening(s) and/or duct(s) in the transducer, such as the opening(s)
or duct(s) used in step 512. After the housing is sealed, flow
proceeds to step 518 where the method ends.
[0075] The present technology described and claimed herein is not
to be limited in scope by the specific example embodiments herein
disclosed, since these embodiments are intended as illustrations,
and not limitations, of several aspects of the present technology.
Any equivalent embodiments are intended to be within the scope of
the present technology. Indeed, various modifications of the
present technology in addition to those shown and described herein
will become apparent to those skilled in the art from the foregoing
description. For example, the present technology has been described
in the context of a medical device, and specifically in the context
of a moving component of an auditory prosthesis. It should be
appreciated that the impulse force damper described herein may be
implemented in any device in which a component may be damaged due
to impulse forces. Such modifications are also intended to fall
within the scope of the appended claims.
* * * * *