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Description  |
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TECHNICAL FIELD
The present invention relates to portable entertainment and personal
communication systems, particularly wearable audio systems which use
earphones.
BACKGROUND OF THE INVENTION
There are many situations where it is desirable to provide audio output for
personal use to be worn or carried near the body. This audio output can be
used for portable entertainment, personal communications, hearing
prosthesis and the like. These personal and portable communications and
entertainment products include, for example, cellular and portable
telephones, AM and FM radios, cassette tape players, CD players, and audio
portions of portable video systems and personal monitors.
The audio output for many of these systems is typically presented to the
wearer through the use of transducers (a/k/a "speakers") physically
positioned in the ear or covering the ear, such as earphones and
headphones. Earphones offer privacy, easier integration with clothing, and
address concerns for fashion and social acceptability. Earphones also have
the additional advantage that when used in conjunction with microphones,
the problem of feedback control is greatly ameliorated. Further, they are
efficient in terms of sound pressure level (SPL) delivered for a given
electrical output.
Headphones, that is wearable devices which cover the wearer's ears, can
provide excellent high fidelity audio and are reasonably comfortable.
However, the headphones are rather obtrusive for many social circumstances
and attenuate environmental sounds.
Earphones, as well as headphones, are often uncomfortable to wear for long
periods of time. Also, earphones and headphones block or attenuate
environmental sounds causing the wearer to lose contact with his or her
surroundings. In this regard, this can compromise safety considerations if
the wearer is engaging in activity such as running, driving a vehicle, or
operating machinery.
There also are a number of small earphone devices in use today which are
placed on or over the wearer's ears, but these are not as efficient in
creating high fidelity sounds as headphones, and also block out
environmental sounds causing the wearer to lose contact with his or her
surroundings.
"Earbud" earphones are also in use today with portable entertainment
systems. These earphones are placed immediately adjacent the ear canal and
provide good audio fidelity, although their placement is sensitive in
order to obtain the best performance. Earbuds also generally become
uncomfortable after extended use and often block and attenuate
environmental sounds at the expense of safety and loss of audio contact
with the wearer's surroundings.
It is commonly desired to provide stereo output, that is two-channel sound,
from these portable entertainment and personal communication systems.
Stereo is particularly used for entertainment purposes and for other
applications of spatialized audio. Stereo audio output is usually provided
to provide a better high fidelity sound for the system. Small loud
speakers are inadequate to create broad-band high fidelity sound, however,
particularly in the low frequency ranges. Typically, an enclosure of some
type is required to secure the necessary reduction of net radiated
intensity, especially in the low frequency audio ranges, in order to
achieve optimum high fidelity sound. For wearable speakers, the
requirement of an enclosure creates a problem. In general, the volume of
the enclosure will be quite small and its acoustic stiffness will dominate
the speaker behavior. The result will be a high resonant frequency and
consequently a poor low frequency response.
Other devices commonly used to provide audio to wearer's ears include
hearing aids. Developments in this area have led to devices which are
comfortable for long periods of time, but they are usually designed
specifically to exclude sounds that might directly enter the ear canal in
order to control feedback. Also, hearing aids are directed specifically to
providing good audio response over the primary speech frequencies and
often specifically de-emphasize low and high frequencies in order to
enhance speech intelligibility. Some hearing aids utilize an electronic or
transducer module which is positioned behind the ear of the wearer or is
integrated into the earpiece portion of the temple of a pair of glasses.
People who wear glasses all the time, or desire to occasionally wear
sunglasses or safety glasses, or need to switch various pairs of
eyeglasses for reading, distance, or the like, encounter problems with
behind-the-ear and eyeglass temple modules. Every time the eyeglasses are
removed or exchanged, the audio function of the hearing aid may disappear.
Also, if the hearing aid utilizes an ear canal insert, it also needs to be
removed which can be an awkward process. Further, if the module is not
integrated into the eyeglass temple, then the temple of the glasses and
the behind-the-ear module may interfere and either cause discomfort, or
position the glasses such that vision of the wearer is impaired or
distorted.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved audio
system for portable entertainment and personal communication systems. It
is another object of the present invention to provide a portable audio
system which provides high quality sound, particularly at low audio
frequencies.
It is another object of the present invention to provide a wearable audio
system which can be easily worn and does not interfere with the person's
activity, whether sports related or otherwise. It is a still further
object of the present invention to provide a wearable audio system which
does not require headphones or speakers to be positioned covering the
wearer's ears and thus blocking environmental sounds.
It is an additional object of the present invention to provide a wearable
audio system which provides high quality audio to the wearer, provides an
insert in the ear, and still allows sufficient transmission of
environmental sounds. It is a still additional object of the present
invention to provide a wearable audio system which overcomes a number of
the problems and drawbacks with present wearable audio systems,
particularly those utilizing earphones.
A still further object of the present invention is to provide a wearable
audio system which allows quick and convenient changing of eyeglasses or
sunglasses without requiring multiple electronic audio modules.
The present invention fulfills these objects and overcomes the problems
with known systems by providing a personal audio system which provides
high quality sound and maintains contact with the wearer's environment
even though an insert is used in the wearer's ear. The present invention
utilizes a module with one or more sealed chambers, each with two
cavities, positioned to provide audio emissions to the wearer's ears
through a small tube. The cavities are separated by a common wall in which
is mounted one or more transducers whose diaphragms communicate directly
with the two cavities. When the transducer is driven at acoustic
frequencies, it produces acoustic pressure within the cavities.
The chamber can be positioned in a module positioned either behind the ear
of the wearer or in the temple portion of the wearer's eyeglasses. For
stereo systems, one of the modules is provided for each of the wearer's
ears. The electronics module can be included as part of the module, or
alternatively situated at another position on the wearer's body or
clothing and hard wired to one or more chambers positioned adjacent the
wearer's ears, such as behind the ears or incorporated in eyeglasses.
A tubular member ("tube") is used to transmit the audio signals to the
wearer's ears. The distal end of the tube is arranged so that its open end
is near the entrance of the ear canal. The open end is held and stabilized
in position in the ear with an acoustically transparent support member
which is inserted into the ear. The support member is preferably made from
an open cell foam material and can be coated for increased comfort. If a
coating is utilized, it is perforated in order to maintain overall
acoustic transparency.
The acoustic pressure at the open end of the tube of a chamber-tube
configuration, for constant transducer input, will be nominally constant
from sub-audio frequencies up to the chamber tube Helmholtz resonance
frequency, where there will occur a peak. Above that frequency, typically
1-4 kHz for small earphone modules, the asymptotic response is a 6 db per
octave rolloff in pressure (12 db in acoustic intensity). Superimposed on
this asymptote are a series of resonant peaks whose frequencies are
determined by the cavity-tube geometry. These resonances can be
substantially reduced by using known acoustic compensation techniques.
This compensation could involve the use of a parallel tube, which is
closed at the end, and acoustic damping elements. It is also possible to
compensate the resonances by using complementary electrical filtering,
e.g. with DSP (Digital Signal Processing). For high fidelity reproduction
of the audio source it is necessary to compensate for the high frequency
rolloff. This can be done electrically with an active filter or with DSP,
using well known techniques.
In another embodiment, compensation for the high frequency acoustical
rolloff can be accomplished by providing another transducer in addition to
the one in the chamber-tube mode, the additional transducer being placed
directly in the ear insert. This transducer is preferably fabricated from
perforated piezoelectric material. The piezo material could also be
positioned around the end of the tube and further could be divided into
annular portions and act as an acoustic peristaltic pump. The two
transducer system is preferably driven from a cross-over network which
directs the low frequencies to the chamber transducer and the high
frequencies to the ear insert transducer, the relative drive levels being
set to achieve a substantially uniform response.
To eliminate problems with eyeglass wearers, or wearers who need to
frequently change pairs of eyeglasses, a behind-the-ear module is provided
which is adapted to be quickly attached to and released from the wearer's
eyeglasses. An adapter mechanism is provided which connects the ends of
the eyeglass temples to the module such that the eyeglasses can be quickly
and easily removed and exchanged as desired.
These and other objects, features and advantages of the present invention
will become apparent from the following description of the invention when
viewed in accordance with the attached drawings and appended claims.
DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates an embodiment of the present invention which uses a
sample chamber, a tubular member and an ear insert member;
FIG. 2 illustrates an alternate embodiment of an ear insert member for use
with the present invention;
FIG. 3 illustrates an alternate embodiment of the present invention which
incorporates an additional transducer in the ear insert member;
FIG. 4 illustrates an alternate embodiment which also uses an additional
transducer in or adjacent to the ear insert member;
FIG. 5 illustrates still another embodiment of the invention utilizing an
additional transducer adjacent the ear insert member;
FIG. 6 illustrates use of the present invention with a behind-the-ear
electronics module;
FIG. 7 illustrates use of the present invention with an electronics module
incorporated into the temple of a pair of eyeglasses;
FIGS. 8 and 8A illustrate a quick-change adapter mechanism for use with the
present invention;
FIG. 9 depicts an alternate embodiment of an ear insert member; and
FIG. 10 depicts a cross-over network for use with the present invention.
BEST MODE(S) FOR CARRYING OUT THE INVENTION
In order to achieve high fidelity performance from a personal communication
system, it is desirable to produce audio at the low frequencies, such as
on the order of 80 Hz or less. Small enclosures and other earphones of
conventional design are unsatisfactory for this purpose. One system for
accomplishing high fidelity sound and providing the necessary low
frequencies, is shown in commonly-owned U.S. patent application Ser. No.
08/482,759, filed Jun. 7, 1995, entitled "Sampled Chamber Transducer With
Enhanced Low Frequency Response", the disclosure of which is hereby
incorporated by reference herein.
In the system shown in that application, sampling chambers are used to
produce the low frequency audio. The sampling chambers have a pair of
cavities and acoustical pressure is provided through a tube connected to
one or both of the cavities. When the open end of the tube is positioned
adjacent the ear of a wearer, the hearing of the low frequencies of the
system is substantially enhanced.
The acoustic pressure at the open end of the tube of a chamber-tube
configuration, for constant transducer input, will be nominally constant
from sub-audio frequencies up to the chamber tube Helmholtz resonance
frequency, where there will occur a peak. Above that frequency, typically
1-4 kHz for small earphone modules, the asymptotic response is a 6 db per
octave rolloff in pressure (12 db in acoustic intensity). Superimposed on
this asymptote are a series of resonant peaks whose frequencies are
determined by the cavity-tube geometry. These resonances can be
substantially reduced by using known acoustic compensation techniques.
This compensation could involve the use of a parallel tube, which is
closed at the end, and acoustic damping elements. It is also possible to
compensate the resonances by using complementary electrical filtering,
e.g. with DSP (Digital Signal Processing). For high fidelity reproduction
of the audio source it is necessary to compensate for the high frequency
rolloff. This can be done electrically with an active filter or with DSP,
using well known techniques.
In a preferred use of the system disclosed in U.S. patent application Ser.
No. 482,759, the sample chambers are combined with separate high frequency
transducers in an audio system. The additional transducers provide better
high frequency audio performance where desired. The sample chambers
transfer the low frequency audio very well. However, above the cavity
Helmholtz resonance, the pressure transfer falls at 6 dB per octave (12 dB
for intensity). The resonant frequency is typically on the order of
100-200 Hz or higher.
As a result, in some circumstances, a transducer or array of transducers in
a sample chamber with the audio output being supplied through a tubular
member, is sufficient to produce high quality sound. In other instances,
it is desirable to provide an additional transducer or array of
transducers to complement the audio from the sample chamber. Various
networks and circuit diagrams for combining the sample chamber and
additional transducers are shown in U.S. patent application Ser. No.
482,759.
In accordance with the present invention, the audio signals are produced by
a module having a sample chamber, as well as a tubular member which is
positioned and stabilized in the ear canal with an ear insert member. A
schematic diagram of such a system is shown in FIG. 1.
In FIG. 1, the sample chamber 10 is incorporated into a module 12. A
tubular member 14 is attached to the sample chamber at one end 16 and
attached to an ear insert member 20 at its other end 18. A small
transducer 22 is positioned in the chamber 10 which is divided into two
cavities 24 and 26. Cavity 24 is sealed, except for a small leak to
equalize atmospheric pressure changes. The second cavity 26 is coupled to
the outside by tubular member 14. The transducer 22 is mounted on a common
wall 28 separating the two cavities 24 and 26. The diaphragm of the
transducer functions as a moving boundary between the two cavities. The
volumes of the cavities 24 and 26 are designed for minimum volume
consistent with using a transducer with adequate volume displacement to
produce the desired acoustic pressure within the cavities and consequently
at the open end of the tube 14.
The module 12 also contains electronic circuitry 13, including amplifiers,
equalizers and the like, as well as the power source, which preferably is
a long life battery, which are standard in the art. Also, the module 12
could be formed as a behind-the-ear module 100, as shown in FIG. 6, or
included as an electronics module 120 positioned on the end of the temple
122 of a pair of glasses 124, as shown in FIG. 7.
In this regard, the present invention is adaptable for use either as a
personal communication system for one ear of the wearer or as a stereo
high fidelity system for both ears of the wearer. In the latter system, a
behind-the-ear module or eyeglass temple module is situated adjacent both
of the ears of the wearer. For stereo systems, the two modules are
connected by appropriate wiring to a common control system. The control
system could be positioned at another part of the wearer's body, such as
at the waist or at the wrist. In this regard, it is also possible to use
wireless transmission of signals from the control system to the module or
pair of modules.
In accordance with the present invention, the end 18 of the tube 14
emerging from the open cavity 26 is arranged so that its open end is
positioned at or near the entrance to the ear canal of the wearer. The
open end of the tube is stabilized in position in the ear with ear insert
member 20. The ear insert member 20 can be molded to fit the individual
wearer's ears, or can be an insert which is formable and usable for a wide
variety of sizes and shapes of ear canals.
The ear insert and support member 20 is made from an acoustically
transparent material, such as an open cell foam material. Acoustically
transparent materials are materials which allow essentially 100%
transmission of sounds through them. In this manner, the wearer has the
ability to hear sounds connected with his or her environment at the same
time that audio from the personal communication system is being supplied
through the tubular member 14.
Foam materials are available which have negligible acoustic loss up to
several centimeters in thickness. The tubular member 14 is secured to the
foam insert 20 either directly, for example, with an adhesive, or by
pressing the tube over or onto a fitting which has been secured into the
foam piece. A fitting 30 of this type is shown, for example, in FIG. 2.
Another embodiment of ear insert member 150 is shown in FIG. 9. A molded or
formed housing 152 is attached to the end 18 of the tubular member 14. The
circular housing 152 has a socket 154 for insertion of the end of the
tubular member, an annular groove 156 and a circular disc 158. The foam
insert member 20 has a central cavity 160, a first portion 162 which fits
over groove 156 and a second portion 164 which fits over the disc 158. The
foam insert member 20 is releasably held in place on the housing 132 in
this manner, and can be easily removed for replacement or the like by
manipulation of the soft foam material.
The housing 152 can be made of any conventional plastic or metal material,
such as Delrin or aluminum, but preferably is made from an acrylic
material.
The foam or other acoustically transparent material used for the ear insert
is shaped to fit comfortably in the wearer's ear. In order to reduce
possible discomfort or irritation caused by long periods of use, the foam
or other material forming the ear insert member can be covered with a thin
layer 32 of highly flexible plastic material. This is shown in FIG. 2. If
a coating 32 is utilized, it is extensively perforated with openings 34 in
order to maintain the overall acoustic transparency of the insert. In this
regard, it may be preferable to only coat the areas of the insert which
contact the ear of the wearer. This also makes it possible to maintain
maximum malleability of the insert to conform comfortably to the wearer's
ear. Further, full transparency of the insert can be maintained if there
are not two opposed perforated walls which may cause attenuating
resonances.
As an alternate embodiment of the invention, an additional transducer 40 is
integrated into the tubular member and ear insert member. This is shown in
FIG. 3. This embodiment provides better high frequency response. As
explained above, even though low frequencies are transferred very well by
the present invention, the cavity Helmholtz resonance may reduce the
efficiency of the system at high frequencies.
Where an additional transducer 40 is utilized, it preferably is made from a
piezoelectric material. In this regard, a satisfactory plastic piezo
material is PVDF, although other equivalent materials could be utilized.
The transducer is preferably on the order of 25 microns in thickness, and
approximately 0.5 cm in diameter. As shown in FIG. 3, the transducer 40 is
preferably molded directly into the foam ear insert member or bonded to
it. Also, the electrical wires or connectors 42 and 43 from the
electronics module to the transducer are protected in this manner from
contact with the wearer's skin.
The piezoelectric transducer 40 also is perforated with a plurality of
small holes or openings 44 in order to maintain acoustical transparency of
the entire ear insert member for external sounds. With appropriate
perforations, the system loses less than one dB of acoustical loss over
the entire audible spectrum.
If desired, additional resonant compensating tubular members with acoustic
damping resisters can be added to the system. These are known in the art.
Also, as indicated above, these additional components preferably, but not
necessarily, are situated in appropriate housings, such as the modules 100
and 120 (shown in FIGS. 6 and 7).
In FIG. 4, the piezoelectric material forming the additional transducer 50
is wrapped around the end 18 of the tubular member 14. The transducer 50
is preferably positioned in the ear insert member 20 or molded into it as
desired. Of course, the open end of tube 14 is positioned to maintain
proximity to the entrance of the wearer's ear canal.
Power is supplied to the transducer 50 by appropriate wires or connectors
52 and 53. If voltage is supplied so as to squeeze the tubular member 14,
as is known, for example, in inkier printers, the tube 14 will shrink and
expand in diameter and generate pressure within the tube. This can produce
the desired high frequency audio for the system.
Alternately, the piezo material can be divided into annular sections or
members 54 as shown in FIG. 5. The annular members are secured or molded
onto the end 18 of the tubular member 14 and connected by wires or
connectors 56 to the electronics module. When voltage is applied to the
separate members 54 on the tube with appropriate time delays which
correspond to the velocity of sound in the tube, an effective acoustic
peristaltic pump is created. This also could be used to produce the
requisite audio frequencies desired for the system.
The two transducer system is preferably driven from a cross-over network
which directs the low frequencies to the chamber transducer and the high
frequencies to the ear insert transducer. The relative drive levels of the
two frequencies are preferably set to achieve an overall subjectively
uniform response.
A cross-over network 180 which can be used in accordance with the present
invention is shown in FIG. 10. The audio signals S are split by band pass
fillers 181 and 182 into a first frequency band 184 which are the lower
frequency signals, and a second frequency band 186 which are the higher
frequency signals. The higher frequency signals are amplified by amplifier
188 and used to drive the piezoelectric transducer (PET) 190. Similarly,
the lower frequency signals are amplified by amplifier 192 and used to
drive the transducer 22 in the sampler chamber 10. Tubular member 14 is
connected to the chamber 10. The fillers 181 and 182 can have either an
analog or digital implementation.
As indicated above, the electronic components of the present system could
be provided in a wide variety of shapes and sizes and positioned at a wide
variety of positions on the wearer. Preferably, however, the components
are all integrated into an module 100 which fits behind the ear 80 of the
wearer, as shown in FIG. 6, or into an eyeglass module 120, as shown in
FIG. 7. In FIG. 6, the module 100 contains the sample chamber 10 and the
electronic components 13, such as the power supply, amplifiers, and the
like. The tubular member 14 is connected to the module 100 at one end and
stabilized and positioned in the ear canal with ear insert member 20 at
the other end. In FIG. 6, the ear of the wearer is referred to by the
reference numeral 80.
In FIG. 7, the module 120 is incorporated onto the ends of the temples 122
of a pair of eyeglasses 124 and preferably contains all of the electronics
13. The tubular member 14 is connected at one end to the module 120 and
positioned in proximity to the entrance of the ear canal of the wearer's
ear 80 within ear insert member 20.
As indicated above, the present invention provides improved systems for
personal communication and entertainment devices and hearing aid devices
which are lightweight, easily portable, wearable by the user, and provide
high quality audio. The audio for the systems could be provided by a
number of various electronic devices and mechanisms known today. These
include, but are not limited to, cellular and portable telephones,
personal communications systems (PCS), AM and FM radios, cassette tape
players, CD players, personal monitors and paging systems, and portable
video systems.
As indicated above, problems are often encountered by wearers who want to
utilize portable, wearable communication, entertainment and/or hearing aid
systems incorporated in behind-the-ear modules, or as part of a pair of
eyeglasses. Problems are encountered with behind-the-ear modules since
they interfere with placement of the earpieces of eyeglasses. Also, if the
module is incorporated into the temples of a pair of eyeglasses, then
problems are encountered when the wearer wants to switch to a pair of
sunglasses, reading glasses, etc. If the module is integrated into one
pair of glasses, then the audio function of the system is removed every
time the eyeglasses are taken off or the wearer must secure duplicates of
possibly expensive electronics and acoustics modules. Also, this may
require removing the ear insert at the same time, which may be awkward.
If there is no integration between the module and the eyeglasses, the
temple of the glasses and a behind-the-ear module could interfere and
cause discomfort, or position the glasses such that vision is impaired or
distorted. The problem becomes especially troublesome when the audio
system is required or desired to be used for long periods of time and
several changes of glasses or removal of the glasses for one reason or
another are required.
For this purpose, an adapter mechanism 60 is utilized, as shown in FIGS. 8
and 8A. The adapter 60 incorporates a first attachment member 62, a second
attachment member 64, and mating connector members 66 and 68. The
attachment member 62 is secured to the tubular member 14 (or alternately
to the module 100). The attachment member 64 is attached to the end of the
temple 122' of eyeglasses 124'. The temples 122' have been shortened by
removal of the earpiece and a tubular member 70 is connected to the
shortened end. The attachment member 64 is attached to or integrated as
part of the tubular connector 70.
The connecting members 66 and 68 are preferably made from Velcro-type
connecting hook and loop members, but can be of any conventional
releasable connector mechanisms known today. For example, a combination of
a permanent magnet and a mating ferrous material could be utilized. With
the quick change adapter mechanism 60, the eyeglasses 124' can be
connected to the module 100 or tubular member 14 in a relatively quick and
easy manner, simply by attaching and detaching the fasteners.
The adapter member 62 can be glued or otherwise affixed to the tubular
member 14. In this regard, a "peel-off" type of adhesive could be used to
secure the member 62 to the member 14. Alternately, the module 100 and
tubular member 14 could be manufactured with adapter member 62 molded or
otherwise integrated into its structure.
The tubular adapter 70 is provided to facilitate use of the adapter member
60 with various sizes and shapes of eyeglass frames. In this regard, with
standard eyeglasses, the temple 122' is cut off at an appropriate point
and the tubing 70 slipped over the end, designed for a snug fit. If
necessary, an adhesive may be supplied inside the tubing 70 to insure a
permanent fitting.
As is understood, if two behind-the-ear modules are utilized, both temples
of the pair of eyeglasses would need to be modified.
When putting on a pair of glasses, the wearer simply must make sure the two
members of the adapter mechanism 60 mate and are snugly engaged. Removal
of the glasses is straightforward. In this regard, the connector materials
forming the connector members 66 and 68 should be selected to provide the
best compromise between a solid, reliable connection and one which is
easily disengaged without dislodging the behind-the-ear module 100.
The subject matter of the present invention as defined by the following
claims is related to the subject matter of U.S. patent application Ser.
No. 08/530,760, entitled, "Earphones With Eyeglass Attachments", which was
filed on the same date herewith.
Although particular embodiments of the present invention have been
illustrated in the accompanying drawings and described in the foregoing
detailed description, it is to be understood that the present invention is
not to be limited to just the embodiments disclosed, but that they are
capable of numerous rearrangements, modifications and substitutions
without departing from the scope of the claims hereafter.
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