Patent Application
20150304759
The present device and methods relate to the structure, operation and manufacture of fluid pumps and the utilization of their output such as in an insertable sound transmission instrument for a user's ear. Specifically, the device and methods relate to such an instrument which can be coupled with any number of electronic sound devices, such as a hearing aid, MP3 player, Bluetooth® device, phone, and the like, while providing improved comfort and control to the user.
The use of headphones for private listening of an audio device, such as a phone, telegraph or the like, began back as early as the 1900's. The original devices provided very poor sound quality and even less comfort to the user. Such devices have come a long way in the last 20 years with noise-reduction, sound control, feedback control and comfort features as well. However, the prior art has typically taken the “one-size-fits-all” approach to function and comfort and has been unable to offer an in-ear device which is individually customizable for a particular user. The present device addresses this oversight in the prior art by providing an in-ear device which is adjustable to comfortably fit each user, while providing full rich sound quality.
U.S. Patent Publication No. 2009/0028356 A1 (the '356 application), published on Jan. 29, 2009, discloses an in-ear, inflatable, diaphonic member (bubble), for the coupling of sound to the ear, wherein a source of static and active pressure is utilized to inflate the bubble and to keep it inflated. As part of this invention disclosure, a diaphonic valve is described that can convert oscillating sound pressure into static pressure to inflate the bubble in the user's ear. This is accomplished while still passing the sound of the program material (music, voice, etc.) through the valve, into the bubble and thus into the ear, with a minimum of attenuation or distortion. Thus a speaker or acoustical driver of the type used in hearing aids, mp3 player ear buds, or professional in ear monitors may be used to generate static pressures to inflate the diaphonic member (bubble), in addition to playing the program material. The diaphonic valve of the '356 application uses a flat valve design where oscillating sound waves cause oscillations in thin elastic membranes, thus opening and closing ports to harvest the positive pressure, pushing cycles of the speaker and venting in outside air during the negative pressure, pulling cycles of the speaker. Embodiments of the present invention supplement the inventive pumping methods which utilize sound energy to both actively inflate and deflate a diaphonic bubble in a user's ear.
Sound waves generate a sound pressure level and transmit mechanical energy. However, the periodic reversal of the sound pressure, due to the oscillatory nature of the sound waves, makes it difficult to harness sound pressure in the form of the type of static pressure necessary to do PΔV work (where P is an applied pressure and ΔV is a change in volume). An example of PΔV work is the inflation of a balloon. Unfortunately, the sound pressure waves pull as much as they push in every wave cycle, resulting in no net pressure for balloon inflation.
Accordingly, it is desirable to achieve design improvements in the diaphonic valve, which harvests static (analog to DC) pressure from alternating (analog to AC) sound pressure waves. The diaphonic valve may be thought of as a fluid pump which uses sound as its energy source, or alternatively it is analogous to an electronic rectifier that converts alternating electrical current (AC) into direct electrical current (DC). In the present device, the diaphonic valve includes such changes as a reduction in the number of moving parts, increased simplicity of design and manufacture, and greater pressure generating capacity.
A synthetic jet is another featured improvement of the present device. A synthetic jet occurs when a fluid (a liquid or gas) is alternately pushed and pulled through a small orifice. As shown in
Luo and Xia have recently described the design of a “valve-less synthetic-jet-based micro-pump” [Z. Luo and Z. Xia Sensors and Actuators A 122 (2005) 131-140]. A schematic of their device, reproduced from their publication, is shown in
The present invention relates to fluid pumps and the utilization of their output. Also, the present invention addresses and solves numerous problems and provides uncountable improvements in the area of earphone devices and manufacturing methods of the same. Solutions to other problems associated with prior earphone devices, whether the intended use is to be in conjunction with hearing aids, MP3 players, mobile phones, or other similar devices, may be achieved by the present devices.
There is disclosed herein an improved fluid pump and the utilization of its output such as in an audio receiver device for in-ear placement of a user which avoids the disadvantages of prior devices while affording additional structural and operating advantages.
Generally speaking, an invention of the present application provides for converting acoustical vibrations, such as sound, into static pressure. This can be accomplished by an inventive pump that transports air or another fluid and pressurizes the air or the other fluid using acoustical vibrations as its power source. The pressurized fluid can be used for inflating a bubble within an ear or for many other useful applications. Moreover, the diaphonic valve described herein can include sound driven micropumps for microfluidic and mems devices, such as chip based medical diagnostic tests or devices.
Also, generally speaking, a closed system is provided around or over an orifice through which a synthetic jet expels its jet of fluid. This closed system, such as a bubble on one side of the orifice and an enclosed space (e.g., a transducer housing) on the other side of the orifice, can contain fluid pumped by the device and also contain the static pressure that the device generates. In providing the fluid pumped by the device, an ingress tube or ingress port can supply the source fluid to the synthetic jet, at or near the edge of the synthetic jet orifice. The other end of the ingress tube can be located outside the closed system into which the synthetic jet expels its jet of fluid.
Further, generally speaking, an invention of the present application, numerously embodied in countless combinations of components, is comprised of an electronic signal generator, an acoustical driver, a sound actuated pump, and an inflatable member.
It is an aspect of the present invention to provide a design and construction for pumping devices that use acoustical energy (sound) to produce air pressure for the inflation, and possible deflation, of a sealing device in the user's ear.
In an embodiment, an improved design for a diaphonic valve utilizes the principle of the Synthetic Jet. A synthetic jet is produced when a fluid is alternately pushed and then pulled back through a small orifice. This is frequently done using alternating pressure waves in the form of sound. Although there is no net mass transfer through the orifice, the asymmetry between the outward jet of fluid produced on the pushing strokes relative to the flow pattern of the fluid sucking on the pulling strokes, produces a net transfer of fluid from the edges of the exterior of the orifice to a sustained fluid jet in front of the orifice. A great deal of experimental and theoretical work has gone into understanding and modeling the operation of the Synthetic Jet. See, Reference No. 1. Papers have been published and patents issued covering devices that use synthetic jets. See, References Nos. 2-9.
In an embodiment of the present invention, a diaphonic valve pump is provided for the inflation of an in-ear balloon. More complex embodiments of the present invention include stacks of multiple synthetic jet generating orifices as well as an oscillating, thin polymer membrane. In one or more embodiments of the present invention, a novel application is provided for the creation of static pressure to inflate or to deflate an inflatable member (balloon). In addition, sound can be utilized to inflate or deflate an inflatable member in a person's ear for the purpose of listening to sound.
In an embodiment of the present invention, the design, fabrication and working mechanism of a diaphonic (sound driven) pumping device is also disclosed. This device works in conjunction with an existing balanced armature sound transducer, of the type currently used in hearing aids and high end audio ear pieces. Alternatively, this device can also work in conjunction with an existing moving coil speakers of the type currently used in headphones, headsets and ear buds. The inventive device acts both as an air pump to inflate an inflatable member in the listener's ear, and also allows the transducer to perform its conventional function of playing audio material. The inflatable member (bubble or balloon), when inflated by the inventive diaphonic pump, produces a comfortable, adjustable and variable ear seal and works with the ear canal to produce a variable volume resonant chamber for safe, comfortable, rich sounding and high fidelity reproduction of audio.
These and other aspects of the invention may be understood more readily from the following description and the appended drawings.
For the purpose of facilitating an understanding of the subject matter sought to be protected, there are illustrated in the accompanying drawings embodiments thereof, from an inspection of which, when considered in connection with the following description, the subject matter sought to be protected, its construction and operation, and many of its advantages should be readily understood and appreciated. The components in the drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. In the following description and throughout the numerous drawings, like reference numbers are used to designate corresponding parts.
a and 1b depict the working principle of a synthetic jet;
a and 2b depict a known synthetic jet based pump design;
a and 63b are bottom and side views of a schematic illustrating a conical orifice and a raised funnel, respectively;
a and 78b are illustrations of possible embodiments of the coupling shown in
While this invention is susceptible of embodiment in many different forms, there is shown in the drawings, and will herein be described in detail, preferred embodiments of the invention, including embodiments of the various components of the invention, with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspect of the invention to embodiments illustrated.
Referring to
The invention is generally comprised of four components, including a transducer, a diaphonic valve, an inflatable member, and a sound tube. The transducer 20 is powered by an electrical source, either AC or DC, to produce a, in some cases reversible, fluid flow using the diaphonic valve. The fluid is used to inflate the inflatable member 30 (aka, bubble) which fits within an ear canal of the user. The sound tube 40 is used to channel sound, fluid, or both, to and from the ear canal, the inflatable member 30, or both.
The following detailed description is organized to cover each of these general components in their numerous variations, as well as additional and alternative components, with specific combinations illustrated and described for exemplification purposes. However, due to the numerous embodiments of the various components, there are combinations of such components which are not specifically discussed herein but which should be considered to be implicit within the present disclosure and encompassed by the appended claims.
Generally, a transducer 20, which produces sound in response to an electrical signal supplied through a cord 50, may be outside of or enclosed within an inflatable member 30 (e.g., bubble 31). If within the bubble 31, the cord 26 passes through one end of the bubble 31 and the transducer sound output is directed out through the other end of the bubble 31 through a sound tube 40. In use, the device 10 is inserted into a user's ear with the cord 26 coming out of the ear and connecting the device to an audio signal generating device 60 such as a hearing aid, a cell phone, a Bluetooth® device, a digital music player, or another communication device. The opening of the sound tube 40, which provides a direct path, uninterrupted by the polymer bubble 31, from the transducer 20 to the outside of the polymer bubble 31, is directed down the user's ear canal toward the user's tympanic membrane, commonly referred to as the ear drum.
Experimental study based from working embodiments of the present device have allowed the evaluation of bubble inflation pressure versus transducer frequency and the power efficiency of bubble inflation versus transducer frequency. For example, these measurements were performed on a device pumped with the pressure generated by a diaphonic valve fitted to the back volume of one-half of a dual transducer (44A0300) manufactured and sold by Sonion of Denmark.
However, the condition of peak pressure generation, also as shown in
While the device can generate the highest pressure at about 4000 Hz (
By comparison,
Finally,
For the present device 10, which inflates a bubble in the ear using sound generated by the device itself (described below), it is important that the power required to inflate the bubble and to keep it inflated is a small enough percentage of the available battery power so as not to adversely impact the device performance. As a general rule, for a hearing aid application the bubble inflation and bubble pressure maintenance should not consume more than about five percent of the available battery energy.
The Data Sheet, shown in
The “Typical Discharge Curve” shown in FIG. 7 assumes a load impedance of 3000 ohms applied for twelve hour periods, with 12 hour rest periods between. This suggests a hearing aid user would use the device for 12 hours per day. The graph shows a battery voltage of about 1.3 volts as being maintained for about 180 hours. The end point voltage appears to be 0.9 volts after a little more than 200 hours. This would imply that the power being dissipated for 180 hours is 1.3×1.3/3000 equal to 0.00056 Watts or 0.56 milli-Watts. This further implies that the energy being expended from the battery over a 180 hour period is about 0.00056 Watts×180 Hours or about 0.101 Watt Hours.
Applying the guideline that the present inflation pump can at most consume five percent of the available battery energy, this would be about 0.005 Watt Hours or 5 milli-Watt hours. If the battery powers the hearing aid for 12 hours a day and provides such service for 180 hours, this would extrapolate to a battery lifespan of approximately 15 days. Thus, the device can consume about 0.3 milli-Watt hours/day for bubble inflation and bubble pressure maintenance. Based on measurements made on one prototype pump (i.e., device pumped with the pressure generated by a diaphonic valve fitted to the back volume of one half of a Sonion dual transducer 44A0300, as discussed above) operating at 3.15 kHz (the most energy efficient condition, as discussed above), capable of generating a bit more than one kPa with a power consumption of about 0.9 milli-Watts, this would indicate a maximum inflating time of about ⅓ of an hour or 20 minutes/day.
Twenty minutes of pumping per 12 hour day (theoretical maximum allowed by a limit of 5% of battery energy) is far in excess of the amount of pumping required to inflate and maintain inflation of a bubble of the present invention, provided that the bubble is a statically inflated (low permeability) bubble, and the diaphonic valve is prevented from leaking with the addition of a check valve, as described in more detail below.
Embodiments of the present device 10 work in conjunction with an existing balanced armature sound transducer, as illustrated in
The working of such a balanced armature transducer is well-known to those skilled in the art. Different designs and different physical embodiments of a balanced armature transducer 20 from different manufacturers may have different physical layouts of the components. However, all possible balanced armature transducers will have certain basic components. These include a diaphragm 28, for the production of sound, which is mechanically connected to the balanced armature 21. Using the interaction of a permanent magnetic field and an electromagnet produced by passing electricity through electrical coils 29, the armature is electronically actuated to produce vibrations of the diaphragm 28. The balanced armature 21 and electrical coils 29 reside in a back volume space behind the diaphragm 28. The front volume, on the opposite side of the diaphragm 28, is continuous with the sound tube by which the audio exits the transducer 20. The invention described here can be produced using any balanced armature transducer containing these basic components, regardless of the details of the layout or arrangement of these components in a particular balanced armature transducer embodiment. Additionally, embodiments of the invention described herein could use a moving coil speaker as its audio and sound energy source rather than a balanced armature transducer. The basic layout of such a device is similar regardless of whether the sound source is balanced armature or moving coil. Illustrations shown herein generally use a balanced armature sound source.
It is common in prior art transducers, as the one shown in
As will be appreciated after studying this disclosure, a closed system is provided in one or more embodiments around or over an orifice through which a synthetic jet expels its jet of fluid. This closed system, such as a bubble on one side of a synthetic jet orifice and an enclosed space (e.g., a transducer housing) on the other side of the orifice, can contain fluid pumped by the device, such as in the bubble, and also contain the static pressure that the device generates. In providing the fluid pumped by the device, an ingress tube or ingress port can supply the source fluid to the synthetic jet, at or near the edge of the synthetic jet orifice. The other end of the ingress tube can be located outside the closed system into which the synthetic jet expels its jet of fluid.
Through the use of the device, both positive pressure in the jet and negative pressure at the sides of the synthetic jet orifice may be directed, or stored in closed systems, and therefore isolated from each other. Accordingly, accumulated pressures, and or vacuums can be directed to do work.
Other additions to the fundamental device that are present in some embodiments include, but are not necessarily limited to, flaps covering the synthetic jet orifice and check valves to prevent backflow when the synthetic jet pump is not operating. The use of a flap or membrane over the synthetic jet orifice enhances the separation of the positive and negative pressures created by the diaphonic valve, thus allowing them to be both contained in separate closed systems with greater efficiency.
One particular embodiment of a diaphonic pumping device uses an orifice located in the surface of a moving diaphragm of a balanced armature transducer or the diaphragm of a moving coil speaker. When the diaphragm 28 vibrates back and forth, the orifice 61 in the diaphragm 28, see transducer 20 of
If the waveform driving the diaphragm 28 is symmetric, then the two synthetic jets (upward into the front volume and downward into the back volume) will be equal in strength, as shown in
With transducer 20 wired such that a rising wave, as shown in
Both the size and location of the ingress port 52 and the size and location of the orifice 61 on the diaphragm 28, if present, influence the acoustical impedance and the air flow impedance that each contributes to the device 10. By tuning these impedances it is possible to control the flow of both sound and air (pressure) through device 10. For example, it is desirable that the audio program sound generated by the diaphragm 28 propagates exclusively or at least predominantly through the front volume of the diaphragm 28, down the sound tube 40, and into the inflatable member 30 (i.e., toward the ear drum). Thus, the orifice 61 in the diaphragm 28 and the ingress port 52 have high acoustical impedance in the audible frequency range. One way this high acoustical impedance is achieved is my making these ports (52 and orifice 61) very small. The same consideration about acoustical impedance applies to the pressure equalization port 56 when it is present. Conversely, the sound tube 40 has a much lower acoustical impedance.
The balance of impedances for air flow influence the working of the device as a pump. If the air flow impedances of the ingress port 52 and the orifice 61 in the diaphragm are balanced or nearly balanced, then it is possible to reverse the direction of overall air flow by changing the wave form driving the diaphragm 28, as in
The end of the co-axial diaphonic valve tube 23 that extends outside of the transducer 20 into ambient air is open. The other end of the tube 23, within the back volume of the transducer 20, is closed off.
Note that the embodiment of
Returning to
An electronic signal is generated by a conventional prior art electronic device shown as a computer chip 64 in the schematic. This signal generates mechanical oscillations in the pressure generating receivers 65 shown. There are two sets of receivers 65 and the other components shown in the figure, one for each of the user's ears. The receivers 65 are electronically driven acoustical drivers (balanced armature or moving coil) of the general type used to create audio signals in prior art hearing aids, headsets and the like. However, the disclosed acoustical drivers (receivers 65) supply an oscillating sound-pressure to the pressure driven pumping devices 27. In the '356 application, a design is disclosed for a sound driven diaphonic valve that both supplies pressure to an in-ear bubble and also transmits sound. This device utilizes a sequence of oscillating flat, membrane valves. In an embodiment in accordance with the present invention, the sound driven pump 27 works in part or in whole on the principles of a synthetic jet (described further herein). Various embodiments of the pump 27 are available that can include, for example, a membrane that operates in cooperation with a valve seat. In such an embodiment, the sound pump 27 passes a static pressure on to the in-ear bubble as well as sound corresponding to the audio program material. In another embodiment, the pump 27 passes static pressure but blocks the transmission of sound, corresponding to noise made by the oscillating drivers (receivers) 65 driving the pumps 27, and prevents this sound from reaching the user's ear. In these embodiments, the acoustical program material is separately supplied via another set of acoustical drivers (not shown). The electrical signal to these other acoustical drivers is indicated by lines 14 and 16 in
The sound actuated pump 27 is connected to the pressure generating receivers (acoustical drivers) 65 via a short or long tube. Additionally, an ingress port 52 has a tube impedance and supplies air to sound actuated pump 27, and an outlet tube 41 carries the static pressure generated on to inflate a bubble of the in-ear device 10. In some embodiments, the tube 41 carrying the pressure from the sound actuated pump 27 to the bubble incorporate inertance filters 42 to dampen the sound created by the pressure generating receivers (acoustical drivers) 65.
In
The device of
Pumping efficiency may also be improved by the incorporation of a thin membrane 39 between the substrates. This membrane 39 contains a pore 43 (or pores) offset from the location of the orifice 36 of the most proximal substrate 34. The membrane material itself may be impermeable to air or it may be a semi-permeable material such as expanded polytetrafluoroethylene (ePTFE).
To allow ease of insertion and removal of the bubble 31 from the user's ear, it is desirable to have a means to switch the ingress and pressure outputs of the acoustically actuated pump 27. This allows the pump 27 to actively blow up the bubble 31 upon insertion into the ear and to also actively deflate, or pump air out of the bubble 31, upon removal from the ear. This functionality can be achieved in different ways. For instance, it can be achieved by manipulation of the electronic waveform signal sent to the acoustical driver providing the sound energy to the acoustically actuated pump 27. Another method of reversing the pumping direction is a routing manifold 46 of the general type shown in
While a manifold 46 or valve to reverse a pressure driven flow of a gas is not novel, its application, as shown in
In order to produce the most compact design for insertion into the ear canal, a flat diaphonic valve 50 was constructed which mounts to the side of a transducer case and which adds 0.4 mm or less to the overall device width. The working principle and practical operation of the flat diaphonic valve 50 is not different from that described above. However, the device disclosed here, has the advantage of compact design fitting onto the side of a balanced armature transducer 24. The entire device, including the transducer and the diaphonic valve 50 is small enough to fit into the user's ear, and is small enough to be partially or fully contained within a bubble 31.
Layer 1 of the valve structure is a plate containing a groove or slot 51 which will become an air ingress channel in the final valve when all the layers are stacked on top of one another. At the closed end of the slot 51 is a circular terminus 55. Layer 2 is a plate with a single small hole 53. When assembled, the hole 53 is aligned with the hole 57 in the transducer housing 45 as well as with the circular terminus 55 of the air ingress channel. The hole 53 in Layer 2 is the orifice of the synthetic jet, which is the heart of the diaphonic valve 50. This orifice is smaller than the hole 57 in the transducer housing 45 and it is smaller than the circular terminus 55 of the air ingress channel.
Layer 3 of the flat diaphonic valve is a rigid frame with a central region spanned by a thin and flexible polymer membrane or film 58. In this particular device, the membrane 58 is composed of polyethylene terephthalate (PET). The membrane 58 could be composed of any of the polymer materials disclosed in the '356 application, which has been incorporated herein by reference, as suitable for use as a membrane in flat diaphonic valves. The membrane 58 could also be a non-polymer film or foil such as a thin metal foil. The membrane 58 is mounted on the underside of the rigid frame of Layer 3 so that in the assembled device this flexible film rests directly on the top of the plate of Layer 2. Above the membrane 58 is a narrow gap, which allows the flexible film 58, below the bottom of Layer 4, to flex upward. A flap 54 is cut in the center of the membrane 58 of Layer 3. In the assembled device, the flap 54 is directly over the synthetic jet port 53 in Layer 2. Layer 4 is a top plate or cover for the diaphonic valve 50. This cover contains an egress port 59 by which air pumped by the diaphonic valve exits the device. In the particular embodiment shown, this egress port 59 connects to an egress air tube 38, which may be used to route the air into a bubble for inflation.
Experimentation with prototype devices has shown that it is often desirable to prevent escape of air from an inflated bubble by leakage back through the diaphonic valve, during time periods when the diaphonic valve is not pumping, but during which the bubble needs to remain statically inflated. To prevent air leakage back through the diaphonic valve, the diaphonic valve itself can be designed to minimize leakage or a check valve may be added to the diaphonic valve by addition of two more layers to the structure of
The disassembled layers of the diaphonic valve 50 with the added check valve 62 are shown schematically in
Layers 1 through 3 are the same as the first three layers in the flat diaphonic valve 50 discussed previously. Layer 4 is a plate with a single small hole 63. The hole 63 is not in the center of the plate, but is closer to one of the ends of the plate, along its long axis. Layer 5 is a rigid frame with a flexible membrane 58 on its lower side, similar to Layer 3. However, in Layer 5, there is no flap, but rather another small hole 66 in the membrane 58, which is located at the opposite end of the structure from the hole in the plate of Layer 4. Layers 4 and 5 comprise the check valve 62. The region of contact of the top of the plate of Layer 4 and the bottom of the film of Layer 5, between the hole 63 in Layer 4 and the hole 66 in the flexible film 58 of Layer 5, comprises the sealing function of the check valve 62. Placing the holes 63, 66 in Layers 4 and 5 at opposite ends of the structure creates the largest possible valve seat for the check valve 62 and thus improves the seal. Finally, Layer 6 is the same cover plate with an air egress port 59.
As shown in
In the device lacking an air ingress channel, air to inflate the bubble 31 is drawn from the ear canal, down the sound tube 40, into the front volume of the transducer 20, through the pressure compensation port 56, into the back volume of the transducer 20, through the pumping diaphonic valve 50 and finally into the bubble 31. This embodiment has the advantage of using air pressure to pull the bubble 31 into the user's ear, producing a good acoustic seal.
The diaphonic valve 50a on the front volume is turned around to pump from outside into the front volume, thus pressurizing the front volume. This pressure leaks through the compensation port 56 into the back volume, thus increasing the pressure of the back volume. The other diaphonic valve 50b on the back volume further increases pressure and pumps air out of the device via the egress port 59. This device can produce higher pressures than the single diaphonic valve on the back volume only. With two diaphonic valves 50, the first valve increases pressure inside the transducer 20 and the second boosts pressure even more before egress. The device in
This produces a cascade of pressure increases. Each transducer and diaphonic valve combination can only increase the pressure so much (about 1 kPa at most). However, by stacking the devices as shown, the second transducer/diaphonic valve combination begins with air which has already been pressurized. It can thus boost the pressure higher. When operating a device such as that shown in
The devices shown in
The devices of
The inflatable member 30 or, more specifically to the illustrated embodiments, bubble 31 is a key component of the present invention. The bubble 31, which can be comprised of an almost infinite number of shapes, sizes, colors, and materials, all as detailed below, serves a variety of functions, including providing retention, comfort, adjustability, and compactability.
Expanded polytetrafluoroethylene (ePTFE) or PTFE are favored materials for the production of bubbles due to a combination of properties including: strength, lightness (low density), tailorable air permeability (through controlled porosity), smoothness of surface feel, and low surface energy, which makes these materials resistant to soiling and dirt accumulation. ePTFE and PTFE suitable for bubble production is available commercially in the form of sheets and films of various thicknesses and porosities. Generally, thinner grades of the ePTFE or PTFE sheet are better for bubble production than thicker grades. Depending upon specifics of tailored bubble design and on the manufacturing processes used, the thickness of the starting film material is typically less than 10 mils, preferably less than three mils, and most preferably one mil or less.
At the time of this filing, bubble production from ePTFE and PTFE films has yielded best results using grades of polymer film having low or negligible air permeability. This is because, in use, it is easier to keep a low or negligible permeability bubble inflated by the action of acoustical pumps than a more porous bubble. However, there are acoustical properties and advantages for ear comfort and ear health that are enabled by more porous and, therefore, more breathable bubbles. This includes the lessening of cerumen buildup as discussed below. Thus, using more air permeable grades of ePTFE or PTFE film in bubbles is not excluded from the present invention.
Other thin flexible polymer films including polyurethane films, thermoplastic polyurethane films, aromatic polyurethane films and aliphatic polyurethane films are also favorable materials for bubble production due to their strength, expandability, processibility, and low air permeability. Polyurethanes are particularly useful when a statically inflated, non-breathable bubbles are desired. Depending upon specifics of tailored bubble design and on the manufacturing processes used, the thickness of the starting polyurethane film material is typically less than 10 mils, preferably less than three mils, and most preferably one mil or less.
In the manufacture of the polymer bubbles for the co-axial diaphonic valve 22 or any of the embodiments disclosed, there is the necessity to form a closed, convex bubble shape. In embodiments in which the sound tube 40 pierces the end of the bubble (various FIGURES), it is still often convenient to begin by producing a closed, convex bubble. The sound tube 40 can be later inserted down the middle of the bubble, attached to the bubble tip, and the bubble material covering the end of the sound tube then cut away. So, mass manufacture can involve production of closed, convex bubbles.
Some polymer films, ePTFE and PTFE thin films, as well as polyurethane films, can support in-plane stretching or expansion without breaking This in-plane expansion can produce some permanent set or deformation within the material which remains after the stretching or expanding force is removed. Thus, bubbles can be formed by stretching polymer films, ePTFE or PTFE films, or polyurethane films over convex mandrels with a variety of shapes: spherical, hemispherical, cylindrical with a hemispherical cap, spherical on top of a thinner cylindrical stem, light bulb shaped (approximately spherical top tapered into a narrower cylindrical stem). Bubble shapes with a larger bulbous top and a narrow stem, the light bulb shape for example, present a problem of removing the larger top of the mandrel through the thinner bubble stem without stretching, deforming, or destroying the thinner bubble stem. This problem is believed to be addressed by using an inflatable mandrel (not shown). In one embodiment of the method, the inflatable mandrel is a small rubber balloon which is blown up to form the polymer film, ePTFE film, or polyurethane film into the correct bubble shape. Then the rubber balloon is deflated so it can be easily removed through the neck of the formed polymer, ePTFE, or polyurethane bubble.
Another approach to stretching polymer film into bubbles with bulbous tops and narrower necks is to use a concave (female) mold of the desired shape (not shown). The polymer film is drawn into the mold cavity under vacuum and/or blown into the mold cavity under positive air or gas pressure. The polymer film enters through a narrow mold neck and expands in a bulbous mold shape. The bulbous ends of the bubbles can easily be removed through the narrow necks of the molds by deflating the bubbles before removal.
Bubbles can also be produced from polymer films, ePTFE or PTFE films, or polyurethane films without in-plane stretching of the film material. One way to do this is to fold or pleat the film material over a convex mandrel (not shown). The film material is gathered or cinched up around the base of the mandrel and can be fixed to a metal or plastic ring (not shown), which would define the base of the bubble. In this method of producing bubbles, it is also helpful if the mandrel is inflatable and can thus be easily removed from the inside of the bubble, by deflation.
Finally, formation of the bubble shape may involve a combination of some amount of polymer film, ePTFE or PTFE film, or polyurethane film stretching, some folding and pleating (especially around the bubble stem and base), and fixing the base of the bubble to a ring or collar. The ring or collar may be part of the sound tube of the co-axial device, it may be part of the separable coupling, or it may perform both these functions as well as being the connection for the base of the bubble.
The polymer film, ePTFE or PTFE film, or polyurethane film from which the bubble of the present invention may be produced can be modified by coatings applied to the surfaces of the films or infused into the porous structures of the films, in cases where the films are porous materials. Coating and infusing agents, include polymer latex coatings, especially polyurethane latex coatings and particularly water soluble polyurethane latex coatings, are preferred. These coatings may be used by themselves or they may be combined with other fillers, modifiers, pigments and the like. For example, colored polymer latex coatings may be used to color the bubble. Or, pigments or dyes may be added to uncolored latex coating materials in order to color the bubble. Coloring of the bubble is one means to distinguish different grades or prescriptions of bubbles (discussed in further detail below). Incorporating additional materials with the bubble material coatings, especially talc and fumed silica, may be used to modify the bubble surface properties to keep the bubble membrane from sticking to itself and/or to keep the bubble membrane from sticking to the user's ear canal.
Experimentally, coating bubbles made from porous materials such as ePTFE with a polyurethane latex was found to produce excellent bubble properties, including very low air permeability. The polyurethane coating was shown to be effective at filling to eliminate or at least reduce the size of most of the pore structures of the original bubble material. The use of a polyurethane latex coating mixed with fumed silica was also found to have excellent properties for bubbles including very low air permeability. The coating fills in some pores and reduces the size of other pores in the bubble film. Additionally, the surface of the film was shown, by electron microscope imaging, to have small jagged embedded particles of fumed silica. When two of such bubble surfaces contact one another, the fumed silica particles get in the way of intimate surface-to-surface contact and thus prevent the two surfaces from sticking together.
Surface coatings may be added to the polymer films, ePTFE or PTFE films, or polyurethane films prior to bubble fabrication. This can be done with conventional spraying or web coating techniques. Coating techniques such as silk screening and ink jet printing are used to apply the coatings to the bubble forming material in some areas and not in others or to apply the coatings in different amounts in different areas of the film. This process produces gradients or patterns in bubble material properties when the films are then fabricated into bubbles. Patterns in the coatings applied to the bubble forming film materials, for instance resulting in concentric rings on the bubble surface, may be used to focus, reflect, refract, damp, or otherwise modify sound in the present device.
Coatings may also be produced on the inner and/or outer surfaces of previously formed bubbles, by dipping the bubbles in coating solution or filling the bubbles with coating solution. Patterned or gradient coating patterns can be produced by these techniques if, for example, the top or the bottom half of an inflated bubble is dipped into the coating solution for a different amount of time than other parts of the bubble. Coating solution may be placed inside the top or the bottom part of an inflated bubble, thus producing patterns or gradients of coatings inside the bubble. The concentration of the coating solutions, and the time that the bubble material is exposed to such solutions can be varied in the dipping and interior coating processes to create additional patterning flexibility.
The following calculations determine the theoretical rate of air loss from a statically inflated bubble. The particular example calculation is for a bubble composed of Kraton® polymer (a block copolymer of polystyrene and a polydiene, or a hydrogenated version thereof). These calculations are also a good approximation for the behavior of expanded polytetrafluroethylene (ePTFE) bubbles that have been coated with Kraton®, as well as for bubbles composed of polyurethane or ePTFE bubbles coated with polyurethane latex. In the case of an ePTFE bubble coated with Kraton®, the Kraton® is much more air permeable than the PTFE scaffolding of the ePTFE. It is assumed that gas leaks through a membrane of Kraton® equal to the total bubble wall thickness (including Kraton® and ePTFE). This provides an overestimate of the air loss, and thus is a worst case scenario.
Characteristics of the bubble used for the estimate are one cm diameter, spherical, with a 0.1 mil (0.00025 cm) wall thickness. Calculations were done for two internal pressures of (relative to outside atmospheric pressure) 100 Pa and 1 kPa.
In general, for transport of a gas through a polymer:
J=P(dp/dx),
where
J is the flux of gas through a polymer membrane having units (cm3 of gas)/((cm2 of membrane) (second)), P is the gas permeability of the membrane, and (dp/dx) is the driving pressure gradient across the membrane, the x-coordinate representing distance in the membrane thickness direction.
The permeability of Kraton® to air is 1×10−9 ((cm3 of air) (cm of membrane thickness))/((cm2 membrane area) (second) (pressure in cm of Hg)) [Reference: K. S. Laverdure “Transport Phenomena within Block Copolymers: The Effect of Morphology and Grain Structure” Ph.D. Dissertation, Chemical Engineering, University of Massachusetts at Amherst, 2001.]
The driving pressure gradient (dp/dx)≈(Δp/Δx) is 295 (cm Hg)/(cm thickness) if the interior bubble pressurization is 100 Pa, and it is 2950 (cm Hg)/(cm thickness) if the interior bubble pressurization is one kPa.
The resulting flux of air through the membrane, J, is 3×10−7 (cm3 of air)/(cm2 of membrane) (second) when the interior bubble pressurization is 100 Pa, and J is 3×10−6 (cm3 of air)/(cm2 of membrane) (second) when the interior bubble pressurization is one kPa. Based on the volume and surface area of a one cm diameter bubble, these calculations indicate that with a 100 Pa internal pressure, the bubble will lose about two percent of its gas in 12 hours and that at one kPa it will lose about 20% of its gas in 12 hours, this time period being the assumed normal length of daily wear. The calculation is an estimate that assumes the air pressure inside the bubble remains constant throughout the process. This is a good approximation for the two percent loss found for 100 Pa, and thus the calculation is quite accurate. However, the estimate is poorer for the 20% loss at one kPa since such a significant loss will obviously reduce the bubble pressure and thus the driving force for further air loss. Thus, the 20% at one kPa is a worst case estimate. The calculation is sensitive to the thickness of the bubble wall. For example, a doubling of the wall thickness to 0.2 mil will cut the gas loss rate in half to one percent for 100 Pa. Increasing the wall thickness to one mil (still a perfectly viable bubble wall thickness for the invention) would cut all calculated loss percentages by a factor of 10.
The calculation is most accurate for a case in which the diaphonic valve is used to periodically top-off the pressure in the bubble. In the present case, to maintain a pressure of one kPa in the 0.1 mil thickness bubble for over 12 hours by intermittent use of a diaphonic valve (described further herein), the device would need to make up about 20% of the bubble volume in the 12 hour period. This is a very small amount of pumping and would fall below the approximate maximum of 20 minutes per day of pumping necessary to stay below five percent of battery use.
Actual experimental investigation of bubbles of the present invention has shown that they can be inflated and remain inflated, with no noticeable loss of pressure for at least a day and in some cases up to a week.
An inflatable ear canal sealing device, such as the present device, must be able to tolerate changes in the outside atmospheric pressure without either losing its seal or causing user discomfort. For instance, if a user with an inflated bubble in his or her ear ascends rapidly to the top of a tall building or ascends in an airplane, the resulting drop in atmospheric pressure will allow the bubble in the ear to expand. Too much expansion of the bubble in the ear may cause discomfort. Conversely, if a user with an inflated bubble in his or her ear descends rapidly from the top of a tall building or descends in an airplane, the resulting increase in atmospheric pressure will reduce the bubble volume. Too much contraction of the bubble may cause the loss of the acoustical ear seal.
As a first step, it is necessary to determine the maximum atmospheric pressure change that the inflated bubble might experience in a user's ear. Then, it is necessary to design the bubble and inflation system to tolerate these atmospheric pressure changes without undue adverse effects of the type described.
For the air in the bubble, pV=constant, where p is pressure and V is volume. This is a subpart of the ideal gas law, called Boyle's Law. It is valid for air over the range of pressures, temperatures and humidities found naturally on Earth.
If Δp is allowed to equal the change in pressure from an initial pressure value, P, and ΔV is allowed to equal the change in volume of the bubble from initial volume value, V, then pV is constant, and we get the equation:
pV=(p+Δp)(V+ΔV). (Eq. 1)
This can be rearranged to show that:
ΔV/V=Fractional Change in Volume=(1/(1+Δp/p))−1. (Eq. 2)
In Eq. 2, ΔV/V and Δp/p necessarily have opposite signs—that is, a positive change (increase) in pressure (Δp/p) leads to a negative change (decrease) in volume (ΔV/V). Also, note that −(100%)*ΔV/V gives the percentage change in volume of an inflated bubble (as positive number) that needs to be dealt with due to a pressure change.
Commercial airplane rides and trips up and down high mountains are more of a challenge with respect to pressure changes in the bubble. As
Another issue for the bubble of the present invention is surface wrinkles. Wrinkles in the bubble surface may result from the natural resting of the bubble along the ear canal surface, which may be rough, for instance, due to the presence of hairs. Also the bubble surface may be intentionally wrinkled by embossing or another mechanical or chemical processing technique. An advantage to wrinkles in the bubble wall is that they can aid the bubble in accommodating slight or moderate volume changes in response to slight or moderate changes in the external atmospheric pressure.
Depicted in
The embodiment in
All embodiments of the disclosed structure utilize sound to either inflate the polymer bubble 31 in the user's ear or to maintain inflation, which may be initially produced by another external means. The sound inflating the bubble 31 may be the program material itself, or it may be a special tone designed to inflate (deflate) the bubble 31. To the extent that the inflation tone may be unpleasant for the user, the end of the sound tube 40 may be closed off during the playing of the inflation tone. However, this feature is only possible for embodiments which employ a means for air ingress other than the sound tube 40. For example, an air ingress tube 37 or groove may be positioned on the outside of the sound tube 40. Without the air ingress tube 37, the only source of air to inflate the bubble 31 is through the sound tube 40. Closing off the sound tube 40 in a device with no air ingress tube, would make it impossible to inflate the bubble 31.
The inflation tone need not necessarily be unpleasant for the user. The synthetic jet based, sound driven pumping can be tuned to different frequencies by adjusting such design parameters and sound tube diameter and length, port location, port size, and the like. Thus the device 10 can be constructed such that that inflation tone or series of tones is pleasant to the user and may become a signature startup sound for the device, similar to the startup tunes commonly played by personal computers, cell phones, and the like. In addition the inflation tone may be at a frequency above or below the hearing range of the user.
The inflation tone may be programmed into a device specifically constructed to use the present technology. However, the inflation tone may also be supplied by an outside source. For example, in a hearing aid, which does not contain recorded program material but which only picks up, amplifies and transmits ambient sound, the inflation tone may be supplied to the device 10 by an external device playing the tone or start up sound sequence. This external device can take the form of a small, handle held, speaker or sound generator, which is held up to the ear as part of the process of starting up the device 10.
Accordingly, in this configuration, a volume of air is trapped in the ear canal between the inflatable seal and the ear drum. The sound tube 40 and sound port through the middle of the donut-shaped bubble 32 allows sound to pass directly from the acoustical driver (receiver) into the trapped volume in the ear canal. In this embodiment, the sound tube acts to both transport the sound energy towards the tympanic membrane and also as a transducer for delivering the sound energy into the bubble space surrounding the sound tube.
This configuration effectively turns around the sealed bubble configuration, which is discussed in detail in the '356 application. As previously indicated above, in this sealed bubble configuration, sound is transported into a sealed bubble 32, which forms a resonant cavity or variable volume in the ear.
In the donut configuration of the present application, sound is transported into the volume between the tympanic membrane (eardrum) and the donut-shaped bubble 32 in the ear canal. The space in the ear canal, therefore, becomes the resonant cavity of variable trapped volume. Additionally, the donut-shaped bubble 32 allows this resonant cavity in the ear drum to be a variable trapped volume because the position and the vibrational compliance of the bubble 32 can be tuned by adjusting the pressure in the donut-shaped bubble 32. This allows precise control of the acoustical properties of the resonating volume in the ear canal and thus of the sound registered on the tympanic membrane.
The tympanic membrane is a vibrating membrane with a back pressure provided by the volume of the inner ear. The inflatable donut-shaped bubble 32 is also a membrane, which vibrates in response to the sound transduced into the trapped volume of the ear canal. Thus, the trapped volume of the ear canal is a resonant cavity closed off by two vibrating membranes, the ear drum and the surface of the donut-shaped bubble 32. By adjusting the pressure in the donut-shaped bubble 32, the mechanical compliance can be adjusted. This influences what portion of the sound (amplitude and frequency) is transmitted into the bubble 32 versus into the tympanic membrane. This form of impedance matching allows precise control over volume and sound quality experienced by the user.
In an alternative or complementary view, the resonance cavity in the ear canal can be viewed as a trapped volume that acts as a compliance to couple acoustic signals from the receiver to the diaphragm/bubble.
The present device 10 can be constructed internal to conventional ear molds with at least one membrane window 71 in the ear mold facing the tympanic membrane, through which the vibrations of the device can access the tympanic membrane (ear drum) of the user. In some embodiments, at least one other port in the ear mold allows the inflatable bubble 31 to be exposed to the ambient environment external to the ear. Variable pressurization of the membrane bladder 72 affords the audio (variable impedance matching and variable resonant volume) and occlusion capabilities of the device within the context of conventional ear molds. Conventional ear molds by themselves (without the inclusion of an internal diaphonic ear lens) do not achieve variable impedance matching and variable resonant volume characteristics.
In
The physical properties of the bubble material, as discussed previously herein, influence the performance of the bubble in the ear. Relevant bubble material properties include thickness, areal density (mass per unit area of film), tensile modulus, strength, elasticity, air permeability, surface hydrophobicity or hydrophilicity, storage modulus, loss modulus, complex modulus, and mechanical damping coefficient. Certain directionally dependent properties (tensile modulus, strength, elasticity, storage modulus, loss modulus, complex modulus, mechanical damping coefficient) of the thin polymer film materials, used in bubble fabrication, may vary with changing in-plane direction. In other words, the polymer films for bubble construction may be anisotropic with respect to certain properties. The polymer films may also be isotropic with respect to directionally dependent, in plane properties. The polymer films used for bubble construction may be anisotropic with respect to some directionally dependent, in plane properties and isotropic with respect to other directionally dependent, in plane properties.
The values of these polymer film properties and the variations of these properties with direction and across the polymer bubble surface control bubble performance. Performance aspects thereby influenced include acoustical transmission of sound to the tympanic membrane, sealing of the ear canal, occlusion of the ear canal, wearer comfort, resonance and variable resonance of the sealed bubble and the sealed portion of the ear canal, sound impedance.
The various bubble material properties can be selected (by careful selection of various types and grades of bubble film material) to produce bubbles tailored to address the hearing problems of a given user or patient. For example, sound transmission and resonance may be maximized in the frequency range where the user has the greatest hearing loss. Different, predetermined prescription bubbles are produced to address common hearing problems, such as hearing loss in various commonly encountered frequency ranges. These prescription bubbles are distinguished by color coding or by different key codes in the separable couplings by which the bubbles are connected to the body of the listening device (including the transducer). Only the correct prescribed bubble and sound tube assembly will fit the coupling on the device. For more unusual hearing needs, it is possible to produce bubbles tailored to those needs of the individual. The individualized bubbles may be assigned a unique key code on their separable coupling. Thus, only the custom prescribed bubbles will fit the listening device of the user with a unique hearing or ear health issue.
Further, different portions of the bubble 31 can be optimized to selectively enhance different functions. For example, the back of the bubble (toward the outside of the ear) may be optimized to block sound transmission, thus improving isolation and avoiding feedback. The waist of the bubble (where it contacts the sides of the ear canal) may be optimized to improve the sealing function of the bubble, or to provide some air permeability for comfort and ear health. The front of the bubble (facing toward the tympanic membrane) may be optimized to enhance to acoustical properties of the trapped volume within the ear canal. A single bubble with gradients in various properties (moduli, permeability, elasticity, damping, etc.) across the surface, performs all or some of the specific functions sought.
An example of a way to produce tailored bubble material properties and to produce tailored gradients of those properties across the bubble surface is by coating or infusing a base polymer bubble material with a modifying agent. A specific example of the process is to take a bubble formed out of a semi-permeable polymer material and infuse a polymer latex into the semi-permeable structure, thus altering the density, permeability, thickness, and various mechanical moduli and coefficients of the bubble material. This type of infusion can be done to different degrees at different areas on the bubble surface, thus, leading to gradients in bubble material properties. A coating process can likewise be varied across the surface of the bubble material creating surface gradients in performance relevant properties.
The described process has yielded useful modifications of bubble properties when the base bubble material is expanded polytetrafluoroethylene (ePTFE) and the infusing latex is a water-based polyurethane latex. By infusing the polyurethane latex into the ePTFE bubble to different extents at different areas of the bubble, gradients in performance related properties are generated on the bubble surface. The extent of latex infusion into the ePTFE is controlled by controlling either the concentration of latex particles in the solution used to treat the ePTFE, or by the length of exposure of the ePTFE to the treating solution, or both.
The sound tube 40 of the present invention can be embodied in several forms based on desired characteristics of device 10.
One or more small ports or orifices 73 in the wall of the sound tube 40 provide a path between the inside of the sound tube 40 and the space inside the polymer bubble 31 (or donut-shaped bubble 32). The small ports or orifices in the sound tube can serve not only as ports for synthetic jet based pumps, as described herein, but also allow sound into the bubble. As such, the sound energy in the bubble is transducted to the ear canal walls, increasing the sound richness.
Accordingly, when the transducer 20 produces sound, the principle of the synthetic jet (described in more detail above) and when present other working aspects of diaphonic valves including flaps, polymer sleeves, ingress ports and the like, leads to a flow of air from the sound tube 40, through the small orifices 73 in the wall of the sound tube 40, and into the polymer bubble 31. In this way, sound energy from the transducer 20 can be used to inflate the polymer bubble 31 in the user's ear.
During the processes of insertion into the ear and inflation, the device, as shown in
The device, as shown in
Other embodiments of this technology include a device 10 similar to that shown in
The device 10 will also work if the sealed and open ends of the polymer sleeve 33 are reversed, i.e. the sleeve 33 is sealed at B and open at A. The device 10 will also work if both ends of the sleeve 33, A and B, are open.
In another working embodiment, both ends, A and B, of the sleeve 33 are sealed. In this embodiment, the polymer sleeve 33 has one or more small holes or ports 74. These holes 74 in the polymer sleeve 33 do not line up with the orifices or ports 73 in the sound tube 40 and they do not line up with any air ingress tube (discussed further herein) openings.
However, for the purposes of continuing the illustration of the invention, an embodiment where the sleeve 33 is sealed at A and open at B is considered.
As shown in the cross-section of
The embodiment of
The air ingress tube 37 has one end outside of the bubble 31 and outside of the ear canal. The air ingress tube 37 runs into the bubble 31 and makes its way to the side of one of the ports 73 in the wall of the sound tube 40.
There is a great deal of possible design variability in the configuration of air ingress tubing 37.
The air ingress tubes 76 do not necessarily need to intersect the ports in the wall of the sound tube 40. As shown in
Employing an air ingress tube manifold 75, of the type shown in
The design features of the ingress air tube system (length and diameter of tubing, size, location and number of ingress air inlets and outlets, etc.) control the amount of resistance or impedance to the flow of ingress air. Air is pulled through the ingress air tubing system under a pressure differential created by the acoustical pumping of the present device. This pump-generated pressure must be sufficient to overcome the line-resistance in the ingress air tube system. By balancing the flow resistance to ingress air and the pumping characteristics of the device 10, the source of air used to inflate the polymer bubble (or to maintain inflation) can be appropriately balance between air from the ear canal (coming down the sound tube 40) and ingress air. For example, it is desirable to use some of the air in the ear canal as part of the bubble inflation, so as to not over pressurize the ear canal upon device insertion. However, it is also desirable not to draw too hard on the air in the ear canal during bubble inflation (or to maintain inflation), since this leads to a partial vacuum in the ear canal, which is also uncomfortable for the user. By tuning the flow resistance of the air ingress tubes, a balance is achieved where the correct (most comfortable) amount of air is taken from the ear canal and the remainder is brought in through the air ingress tubing.
Embodiments of all the designs shown in
In other embodiments,
In all of the embodiments in
The waveform supplied to the acoustical driver providing the sound to operate the acoustically actuated pumping device as a great influence on the pumping performance. For example, the type of wave form shown in
By adjusting the waveform it is also possible to cause an acoustically actuated pump 27 of the type which do not contain seated membrane valves (described herein), to run backwards. Thus, electronic waveform control can be used in this case to achieve the same type of pumping reversal as previously shows with the pressure routing manifold.
It is also possible to reverse the pumping direction of the acoustically actuating pump 27 by manipulating impedance through the use of different sized ingress and pressure outlet ports. However, this approach is less useful for inflating and deflating the in-ear bubble 31 since it requires physically changing tubes. Use of pressure routing manifold 46 (
When using the diaphonic valve 22 or 50 to pressurize an inflatable member (such as the inflatable bubble 31) it may be desirable to be able to sense the pressure achieved and the regulate pumping through a feedback mechanism. This can prevent over- or under-inflation of the system. A backpressure on the diaphonic valve 22 or 50 increases the pressure loading on the transducer 20, which is driving the pumping system. The degree of pressure loading on the transducer 20 alters the electrical impedance of the transducer 20. Measurement of this transducer impedance, therefore, provides a measure of the speaker loading and thus of back pressure in the system. Feedback circuitry can then be used to monitor and control transducer operation, as sensed by transducer electrical impedance, for the purpose of maintaining control of system pressurization.
Additionally, the use of pressure sensing devices (not shown) within or external to the audio or pressurizing transducers may be coupled to appropriate feedback-servo circuitry to achieve pump/pressure regulation which can be programmable.
As described herein, the utility of being able to reverse the pumping direction of the diaphonic valve 22 or 50 is of some value. It allows control of pressure levels in the inflatable member 30 and also allows active deflation as well as active inflation of the bubble 31 (or 32). Two methods of achieving a reversal of pumping direction are disclosed herein, including a routing manifold 46 (
A third method of reversing the pumping direction of the diaphonic valve 22 or 50 is to mechanically alter the acoustic and static pressure impedance of the ingress port and tube to achieve a reverse flow operation of the valve. Appropriate restriction of the ingress flow and or changing the acoustic impedance of the ingress port orifice and tube to the audio frequencies used within the diaphonic valve 22 or 50 results in a reversal of flow within the device 10. This allows the diaphonic valve 22 or 50 to be variably switched between inflation and deflation modes without the use of the routing manifold or similar device. Without limitation to such approaches, flow restriction methods can include devices which mechanically reduce the inside diameter of malleable tubing attached to the diaphonic valve ingress tube 37, or in the case of a port which employs no ingress tube a cone tip may be variably advanced into the ingress port orifice to achieve flow reversal. Thus, application of a flow spoiler of some sort to the ingress port or ingress tube can be used to reverse the flow of the diaphonic valve 22 or 50.
If, however, the symmetry of the system is broken one of the two synthetic jets will be stronger than the other and the device 10 will pump in one direction over the other.
Additional ways to break the symmetry of the system is to have the orifice 61 in the moving diaphragm 28 shaped like one of either a conic depression or a raised funnel, each of which faces in one direction but not the other. These embodiments are illustrated in
In
The examples described and shown here have each had one ingress port 52, one pressure equalization port 56 and one port 61 in the diaphragm 28. However, other embodiments in accordance with the invention can include multiple ingress ports, multiple pressure equalization ports and multiple ports in the diaphragm. Moreover, other embodiments in accordance with the invention can combine pressure equalization port(s) with port(s) in the diaphragm. The location of the orifice 61 in the diaphragm 28 may be varied in different embodiments to produce different pumping effects. For example, a location of the port 61 near the center of the diaphragm 28, where excursions are greater, produces a larger pumping effect than locations of the port near the edge of the diaphragm 28.
In the pumping embodiment shown in
By reversing the asymmetry conditions of the moving orifice 61 in the system (making the conical pore entrance face the other way or changing the phase of the asymmetric wave form by 180 degrees) the device 10 can be made to pump in reverse. In this case the ingress will become the egress and vice versa. A device of the type in
The pumping efficiency of the device 10 in
In
The embodiment shown in
The effect can also be achieved through the use of a single transducer which employs the use of sound delivery tubes constructed so as to optimize the phase and attack differential at the membrane orifices between two sound waves emanating from the same transducer diaphragm, either from one side of the transducer diaphragm or from both.
Greater forward direction (inflation of the bubble) pumping efficiency can be generated by combining the co-axial diaphonic valve 22 in the transducer back volume with a port 61 in the diaphragm 28, as shown in
The embodiments of
In the various embodiments disclosed here, the transducer back volume acts like a pressure ballast tank. It must be pressurized before pressure can be transferred to the inflatable member 30. Thus, approaches to reduce the back volume of the transducer 20 result in a more responsive and efficient pumping device. This applies to all the embodiments disclosed herein.
The approach of adding a partition to the back volume can be applied to any of the embodiments presented in this disclosure. When this is done, it is necessary that these valves connect to or reside in the smaller partitioned off part of the back volume used for pressure generation.
The use of pressurizing mechanisms, such as an acoustically driven diaphonic valve, provides pneumatic operation of devices at or near the same location of the inflatable bubble 31. In an embodiment depicted in
As depicted in
In operation, as pressurized fluid enters the cylinder 93 from the pressure delivery tube 69 (
Once the inflatable bubble 31 is to be deflated and removed from the user's ear, pressure is relieved from the cylinder 93 via the pressure delivery tube 69 (
Previously, it was shown that a particular embodiment of device 10 built with a Sonion 44A0300 dual transducer has its best energy efficiency for pumping air to inflate a bubble in the ear at a frequency of about 3 kHz. At this operation frequency, the device 10 can inflate and maintain inflation of a bubble 31 in the ear over a 12 hour period, using less than five percent of the available battery power in a typical hearing aid. However, doing this requires initial and perhaps intermittent use of an inflation tone of about 3 kHz at a considerable amplitude (loudness). This tone may be unpleasant to the user.
Other embodiments, based on other transducers and other diaphonic valve configurations, may have their most energy efficient pumping at somewhat different frequencies. However, all such devices will have a frequency or range of frequencies in which pumping is most efficient, and this tone will often have the potential to be unpleasant to the user when played with sufficient amplitude (loudness) to effect bubble inflation.
To mitigate this potential problem of an unpleasant inflation tone, the present invention preferably uses two transducers in a device 10. The acoustical output of the two transducers, during the inflation of the bubble, is partially or completely out of phase so as to produce a noise cancellation (reduction in amplitude) and/or a shift in the audible frequency, so as to make the inflation process less objectionable to the user.
An embodiment of this invention includes a balanced armature transducer, as previously described, paired with a second transducer. The device generates pressure from sound pressure oscillations in the back volume of one of the transducers, and this pressure is used to inflate the bubble 31 (closed or donut-shaped) in the user's ear. The other transducer is used to produce a sound output which is matched (to the degree possible) in frequency and amplitude and is 180 degrees out of phase with the output of the first transducer. This arrangement quiets the device during bubble inflation.
For this device 10, during normal hearing aid (or other audio) operation, one of the two transducers can be turned off and the other transducer can provide the audio material to the user. This requires a switching scheme, which may be mechanical or electronic, in which one transducer is turned on and off. It is also possible to run both transducers in phase, and thus reinforcing each other's signal, during normal hearing aid operation. This requires a switching scheme, which may be mechanical or electronic, in which one transducer has its electrical input reversed (180 degrees out of phase for bubble inflation) and then switched back (in phase for normal listening).
Another example is a two transducer device, in which the audio output of the two transducers may be run out of phase during bubble inflation to quiet the device, but in which both transducers are incorporated into pumps working from their back volumes. With two pumps working to inflate the bubble 31, device 10 will inflate the bubble 31 more quickly. It is desirable to the application for the bubble inflation process to be quick (less than 20 seconds and preferably less than 10 seconds), as well as quiet.
A device providing active sound cancellation using two transducers can inflate a bubble 31 in the user's ear and can pump air to maintain inflation while continuing to play audio program material (hearing aid function, communications, MP3 audio, etc.). This can be achieved by superimposing the audio material signal on the inflation tone in one of the two transducers. The other transducer plays only the inflation tone, but 180 degrees out of phase. The net effect is that the inflation tone is fully or partially cancelled and the audio signal remains intact.
Alternatively, in a two transducer device (previously described herein), both transducers can play audio material, which may be the same or different, but which is not out of phase and which does not cancel itself out. At the same time, superimposed on this audio material, in each transducer, is the inflation tone. However, the two transducers play the same inflation tone 180 degrees out of phase with one another, producing a cancellation or partial cancellation of the inflation tone, while the audio material from both transducers is heard by the user.
As shown in
The prototype in
In normal use, the bubble 32 and the sound tube 40 may become soiled and may need to be cleaned. The separable coupling 100 allows the bubble 31 and sound tube 40 to be removed from the rest of the device 10 for easier cleaning
Additionally, the bubble 31 and sound tube 40 may become worn out due to usage or may be damaged in handling by the user. The separable coupling 100 allows a damaged, worn or soiled bubble and sound tube assembly to removed and replaced by a clean and/or new one. Due to the relatively delicate nature of the bubble 31 and the polymer sleeve 33 covering the sound tube 40, the bubble 31 and sound tube assembly is by design a disposable part of the device 10. It is designed to be periodically removed and replaced with a new bubble and sound tube assembly.
The use of a separable bubble 31 and sound tube assembly 40 can also be coupled with other pumping mechanisms besides the coaxial device 10. For instance, it can be coupled with a synthetic jet acoustical pumping device based on orifices in plates or with other diaphonic valve embodiments, each as described herein.
The separable coupling 100 between the replaceable bubble 31 and sound tube assembly 40 and the transducer 20 will necessarily include connections for the air ingress routes, in embodiments that employ such air ingress routes. The embodiment shown in
The bubble 31 (or 32) and sound tube assembly 40 can be made in different sizes to accommodate the natural variation in ear canal dimensions among users. Additionally, by tailoring the properties of the bubble material (strength, stiffness, elasticity, density, air permeability) different bubbles types can be produced, for example, to suit hearing aid patients with different hearing or ear related issues.
Thus, especially in the hearing aid application, the bubble 31 and sound tube assembly 40 can be considered a prescription analogous to prescription contact lenses for the eyes.
The simplest embodiment of the separable coupling, shown in
The coupling 100 connecting the removable bubble 31 and sound tube assembly 40 to the transducer 20 and the body of the device 10, may be color coded to help the user choose the correct prescription bubble. In this case, the audiologist, when prescribing the device will fit the body of the device 10 with a coupling of a specific color, which matches the color of the coupling on the prescription bubble appropriate for the particular patient.
b shows an example of a “lock and key” recognition system for the separable coupling by which the bubble 31 and sound tube assembly 40 are connected to the transducer 20. A pattern of markings on the mating surfaces of the separable coupling must match for the coupling to be made. Different prescription bubble and sound tube assemblies will have different patterns in their half of the separable coupling. These will need to match the markings in the other half of the coupling on the fixed body of the device, by the transducer. The half of the coupling fixed onto the device will be determined by the prescribing doctor and will make sure the patient is only using the appropriate bubble and sound tube assemblies. Lock and key matching of the appropriate prescription bubble and sound tube assembly with the body of a user's device can also be combined with color coding of the coupling previously described. This provides a convenient method for the user to select the correct bubbles based on color of the coupling combined with a failsafe mechanism, based on lock and key matching to prevent the attachment of the wrong bubble.
The lock and key aspect of the separable coupling can be achieved with the shape, spacing and depth of grooves in concentric cylindrical surfaces, as shown in
The lock and key coupling 100 may be held together by friction as shown in
Different combinations of two or more of the locking and recognition mechanisms described are possible.
When embodiments incorporating air ingress tubes that feed air from around the back of the transducer are combined with a removable sound tube and bubble assembly, then the separable coupling must including a feed-through for the air ingress route.
The air ingress tube 37 through embodiments shown in
The air ingress tube 37 through embodiments in
The inflation of the polymer bubble 31 may be supplemented mechanically by external devices located outside the ear canal, either directly outside the ear or on a cord connecting the device 10 to an external electronic device, such as a digital music player. These external pumping devices may be electronically or manually powered. Air is injected into the polymer bubble 31 through the air ingress tube 37 as illustrated in, for example,
An example of supplemental pumping methods for the device 10 include a syringe pump (not shown) or variations of the syringe pump concept. A plunger, which may be a rod or sphere, is moved through a tube to compress the air in front of it. The tube containing the compressed air of the syringe pump is connected to the inside of the bubble, and thus the syringe pump may be used to inflate or deflate the bubble by pushing or pulling the plunger in the tube.
Other examples of supplemental pumping methods for the device 10 include diaphragm pumps (not shown) in which a flexible diaphragm is mechanically depressed to squeeze air out of a chamber enclosed by the diaphragm. The chamber has two check valves, where one valve opens when the chamber is pressurized to allow air to flow from the chamber toward the polymer bubble and the other check valve closes under pressure, but opens under partial vacuum and thus allows the chamber to refill when the diaphragm is released.
Another example of a supplemental pumping method for the device 10 includes squeezing the tube itself that connects the bubble to the outside air. The tube containing appropriate check valves then functions in similar manner to the diaphragm pump described herein.
Still another example of a supplemental pumping method is to perform a peristaltic pumping motion on the tube connecting the bubble to the outside air. This peristaltic action may be performed manually or via a power driven peristaltic pump.
Inflation of the polymer bubble 31, deflation of the bubble 31, and maintenance of pressure during use of the device 10 can be achieved either by the external methods described herein, by the pumping action of the device pump 27, or by a combination of external methods and device pumping. For example, an external method may be used to supplement the pumping of the device 10 for quick inflation and deflation, while the pumping action of the device pump maintains bubble pressuring during use.
Loss of the ear canal seal in a hearing aid can lead to unpleasant and potentially dangerous feedback because the hearing aid speaker and microphone are in close physical proximity and are no longer isolated from one another. Embodiments of the present device 10 preferably include a control mechanism (not shown), which may be either hardware (electronics) or software based. When the feedback control is activated the gain of the electronic device is temporarily reduced. In response to this action, the device 10 is directed to increase its pumping action, thereby increasing the inflation in the polymer bubble 31 and improving the ear canal seal. This pressure increase, triggered by the onset of feedback, then reduces the feedback coupling path between the device receiver and microphone.
The ribs 105 may or may not be permeable to air. They function to set the distance between the inner wall 103 and outer wall 104 of the bubble 31 when inflated and they do not need to be impermeable to air to achieve this purpose. The ribs 105 may be made of an air permeable material or they may have holes in them. The ribs 105 may also be replaced by an arrangement of discrete posts that fix the distance between the inner and outer surfaces of the double-walled bubble 31.
This embodiment of the device 10 has less stringent pumping requirements to inflate the bubble than the embodiments shown in, for example,
Similar to the double-walled bubble 31 embodiment of
This design requires a circular pressure manifold, whereby pressure generated by the diaphonic valve is distributed to each of the tubular bubble wall sections. The example shown in
The inflatable, tubular sections 106 of the device in
The bubble 31 can be formed from as few as six tubes 106 and as many as twenty or more tubes 106. The number of tubes 106 is eventually limited by the need to distribute air flow and pressure to all of them via a pressure manifold.
A two tone ear seal test has been described for conventional ear tips including foam, silicone, or rubber inserts: http://www.sensaphonics.com/test/index.html. This approach can be applied to evaluate the ear seal obtained with the present device 10. In this approach the user inserts the device and then listens to a lower frequency tone (50 Hz as an example) and a higher frequency tone (500 Hz as an example) played in succession and then together at the same volume level. When the two tones are played together, if the user hears them both at about the same level, then the ear seal is good. If the two tones are not at or near the same level the device needs to be adjusted to obtain a better ear seal.
Any of a number of methods for venting the pressure in the bubble, either slowly for removal by the user, or rapidly (for example, via a rupture disk-like pressure release valve) as a safety feature to prevent over pressurization of the bubble and potential bursting in the ear are preferably employed for the embodiments of the present invention. Other safety features include a tether on the bubble or bubble and sound tube assembly that allows them to be removed from the ear should they become separated from the in-ear audio device. All of these previously disclosed methods and devices can be applied with the new embodiments described in the present disclosure.
Embodiments of the flat diaphonic valve 50 shown in
The layers of this structure can be made out of a wide range of materials such as steel, stainless steel, aluminum, other metals, polyethylene terephthalate (PET), polyether ketone (PEK), polyether etherketone (PEEK), polyamide (nylon), polyester, polyethylene, high density polyethylene, polytetrafluroethylene (PTFE), expanded polytetrafluorothylene (ePTFE), fluoropolymer, polycarbonate, acrylonitrile butadiene styrene (ABS), polybutylene terephthalate (PBT), polyphenylene oxide (PPO), polysulphone (PSU), polyimides, polyphenylene sulfide (PPS), polystyrene (PS), high impact polystyrene (HIPS), polyvinyl chloride (PVC), polypropylene (PP), polyolefins, plastics, engineering plastics, thermoplastics, thermoplastic elastomers, Kratons®, copolymers, or block copolymers. The layers can also be composed of blends or composites of these materials or versions of these materials to which have been added fillers, modifiers, colorants, and the like. Different layers of the structures may be composed of the same material or of different materials.
As an example, the version of the device shown in
The length and cross section of the channels in the layers of
The layered diaphonic valve structure of
An example of a manufacturing process to produce many assembled copies of the diaphonic valve of
Once all the sheets containing the substrates are bonded together (
The underside of Layer 1 of this diaphonic valve structure, which rests on the sound source, such as the casing of a balanced armature transducer may be produced with a coating of adhesive. This adhesive remains inactive throughout the manufacturing process of the multilayered diaphonic valve structure as described above. This adhesive on the underside of Layer 1 may be activated by heat, radiation, or the removal of a backing layer, and once activated allows the bonding of the entire, assembled diaphonic valve to the sound source.
Multiple diaphonic valves may be fabricated in the same layered, stacked, substrate arrangement. They may be arranged either in parallel or in series or in a combination of parallel and series connections.
Embodiments exist in which Layer 4, containing one flap for each synthetic jet orifice, is absent and the synthetic jets operate without a flap. Embodiments also exist in which a flap is present on the downstream side of the orifice for the reversed synthetic jet diaphonic valves, but there is no flap present on the forward operating synthetic jet diaphonic valves. Embodiments also exist in which a flap is present on the downstream side of the orifice for the forward operating synthetic jet diaphonic valves, but there is no flap present on the reverse operating synthetic jet diaphonic valves.
The build-up of cerumen on in-ear devices is a persistent problem, which can foul the transducers and other mechanical and electronic parts of hearing aids, headsets and other in-ear listening devices. Cerumen exists in the ear canal both as a waxy solid and also as a vapor phase. This cerumen vapor can permeate parts of an in-ear device (for instance a receiver in canal, RIC, hearing aid) such as the inside of sound tubes and the internal structure of balanced armature transducers, which are not in direct contact with the inner surface of the ear canal. The cerumen vapor can then condense to a solid, thereby fouling the internal structures of in-ear devices. Cerumen vapor fouling is also a problem for electronics and other structures placed within the ear. This fouling with cerumen is a major cause of the failure of hearing instruments and other in-ear devices.
The diaphonic valve in any of the embodiments disclosed in this patent can be used to reduce or eliminate the cerumen fouling of in-ear devices by creating a positive pressure in the front volume of the transducer and in the sound tube, which prevent the infiltration of cerumen vapor. A slow flow of air, pumped by a diaphonic valve or valves, through the in-ear device, which can include the body of a hearing aid, and ultimately out through the ear also can flush this vapor out of the ear canal and reduce cerumen in the ear canal an on the outside of the in-ear device. This flushing also mitigates heat and the effects of sudden atmospheric pressure changes which can be uncomfortable for the wearer. This flushing process requires the use of an ear tip or ear seal which allows for the escape of small amounts of flowing air. The various in-ear bubbles described herein provide an example of such a gentle ear seal which can allow the escape of small amounts of air. Additionally, this positive pressure, cerumen flushing system based on diaphonic valves generating pressure from sound is applicable to open architecture receiver in canal (RIC) listening devices, since the flowing air can escape the ear canal. A small vent can be placed in closed architecture ear tips for the expulsion of pressure, cerumen vapor, humidity and heated air.
A positive pressure and a slow flow of air to reduce cerumen build up can be achieved using a range of diaphonic valve embodiments.
It should be emphasized that the above-described embodiments of the present invention, particularly, any “preferred” embodiments, are possible examples of implementations merely set forth for a clear understanding of the principles for the invention. Many variations and modifications may be made to the above-described embodiment(s) of the invention without substantially departing from the spirit and principles of the invention. All such modifications are intended to be included herein within the scope of this disclosure and the present invention, and protected by the following claims.
The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only and not as a limitation. While particular embodiments have been shown and described, it will be apparent to those skilled in the art that changes and modifications may be made without departing from the broader aspects of applicants' contribution. The actual scope of the protection sought is intended to be defined in the following claims when viewed in their proper perspective based on the prior art.
The present application is a continuation of U.S. application Ser. No. 13/782,212, filed Mar. 1, 2013, which is a continuation of U.S. application Ser. No. 12/777,001 titled “Inflatable Ear Device” and filed on May 10, 2010, now U.S. Pat. No. 8,391,534, which claims priority to U.S. application Ser. No. 12/178,236, to Ambrose et al., filed on Jul. 23, 2008, now U.S. Pat. No. 8,340,310, and to each of the following provisional patent applications: U.S. Application Ser. No. 61/176,886, filed on May 9, 2009, Application Ser. No. 61/233,465, filed Sep. 12, 2009, Application Ser. No. 61/242,315, filed Sep. 14, 2009, Application Ser. No. 61/253,843, filed Oct. 21, 2009, and Application Ser. No. 61/297,976, filed Jan. 25, 2010. The complete content of each of the above-listed applications is hereby incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13782212 | Mar 2013 | US |
| Child | 14586293 | US | |
| Parent | 12777001 | May 2010 | US |
| Child | 13782212 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 12178236 | Jul 2008 | US |
| Child | 12777001 | US |
