(*) Notice:
`
`Subject to any disclaimer, the term ofthis
`patent is extended or adjusted under 35
`US.C. 154(b) by 0 days.
`(21) Appl. No.: 09/413,680
`(22)
`Filed:
`Oct. 7, 1999
`
`Related U.S. Application Data
`
`(62) Division of application No. 08/942,963, filed on Feb. 23,
`1998.
`
`HO4R 25/00
`Int. C1?
`(51)
`(52) U.S. Ch. cece 381/323; 381/328; 381/322
`:
`(58) Field of Search o....c.cccccccceeeeee 381/322, 323,
`381/327, 328, 331, FOR 127, FOR 132,
`FOR 133, FOR 135, FOR 137; 429/163,
`164, 175, 176, 94, 161, 209, 186
`
`56
`(56)
`
`ABSTRACT
`.
`.
`.
`.
`A contactless rechargeable hearing aid system in which a
`rechargeable hearing aid may be optically or inductively
`recharged by an optical or an inductive recharger. The
`optically rechargeable hearing aid may have a dual Purpose
`optical fiber that mayactas a light conduit for the recharging
`light, and that may also act as a draw string for the hearing
`aid. The rechargeable hearing aid may use a high energy
`nickel metal-hydride rechargeable battery or a high energy,
`high voltage lithium based rechargeable battery, in conjunc-
`tion with a DC to DC voltage regulating circuit for convert-
`ing the rechargeable battery’s declining DC output voltage
`Cited
`Ref
`to the fixed DC input voltage needed by the hearing aid’s
`&NE
`emerences
`audio related circuitry. The DC to DC voltage regulating
`U.S. PATENT DOCUMENTS
`circuit may also help to present a supply impedance that
`> 901.551
`179/107
`8/1959 Passow
`matchesthe input impedanceofthe audio related circuitry in
`2950357
`8/1960 Mitchelletal.cccccccceee.~ 179/107
`
`the hearing aid. The rechargeable battery may have an
`3,007,110
`10/1961 Rosemstrach seessevseseeseeeesenee 324/53
`
`alternately folded cell stack, a spiral wound cell stack or an
`3,272,653
`v.ecceeeeeeeeeeee 123/6
`9/1966 Solomonet al.
`
`
`accordion folded cell stack, in order to provide, in a mini-
`3,764,748
`10/1973 Branchetal. ..
`179/107 E
`mized volume, the large anode, cathode and electrolyte areas
`3,818,691
`6/1974 Uchiyama wi. 58/23
`
`3,844,840=10/1974 Bender weet seeeeee 136/89 that may be needed to reduce the rechargeable battery’s
`
`oscar
`11/1975 wos etal.
`.
`+» 320/2
`output impedance, in orderto help reduce internal resistance
`Foeea yor es TRUS vcecsceeseeeoeee 429/48
`losses during use of the battery.
`4,293,808
`10/1981 Varadi et al.
`.
`4,379,988
`4/1983 Mattatall .
`
`United States Patent
`US 6,310,960 B1
`(10) Patent No.:
`(12)
`Saaski etal.
`(45) Date of Patent:
`Oct. 30, 2001
`
`
`US006310960B1
`
`(54) RECHARGEABLE HEARING AID SYSTEM
`
`1/1989 Farmont.
`4,800,803
`11/1989 Grimmeretal. .
`4,882,239
`8/1990 Ohsawaet al.
`.
`4,948,685
`Inventors: Elric W. Saaski, Bothell, WA (US);
`(75)
`Boone B. Owens, Wrightsville Beach, 5,210,804=5/1993 Schmid .
`
`NC (US); Michael Bizak, Kirkland,
`5,253,300
`10/1993 Knapp.
`‘
`se
`5,279,292
`1/1994 Baumannetal. .
`WA(US); Stefano Passerini,
`5,303,305
`4/1994 Raimoetal. .
`Minneapolis, MN (US)
`_
`.
`:
`(73) Assignee: Research International, Inc.,
`Woodinville, WA (US)
`
`(List continued on next page.)
`
`OTHER PUBLICATIONS
`
`Long Life, Rechargeable Hearing Aid; Owens, Boone B.;
`Aug. 14, 1995; pp. 1-72; Small Business Research Program,
`Phase II Grant Application.
`(List continued on next page.)
`Primary Examiner—Sinh Tran
`(74) Attorney, Agent, or Firm—Gregory W. Moravan
`
`(57)
`
`27 Claims, 14 Drawing Sheets
`
`i6
`
`
`
`
`
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`N
`
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`1
`
`APPLE 1072
`Apple v. GUI
`IPR2021-00471
`
`1
`
`APPLE 1072
`Apple v. GUI
`IPR2021-00471
`
`

`

`US 6,310,960 B1
`
`Page 2
`
`U.S. PATENT DOCUMENTS
`
`5,303,306 *
`5,316,875
`5,411,535
`5,411,537
`5,455,999
`5,525,441
`5,567,548
`5,580,683
`5,610,494
`5,618,318
`5,646,815
`5,693,105
`5,807,645
`5,879,836
`
`.
`
`4/1994 Brillhart et al. oe 381/323
`5/1994 Murai et al.
`.
`5/1995 Fujii et al.
`.
`5/1995 Munshietal. .
`10/1995 Weiss et al.
`.
`6/1996 Reddyet al.
`10/1996 Walk etal. .
`12/1996 Takeuchiet al.
`3/1997 Grosfilley .
`4/1997 Reddyetal. .
`7/1997 Owensetal. .
`12/1997 Kawakami.
`9/1998 Takeuchi etal. .
`3/1999 Ikeda et al.
`.
`OTHER PUBLICATIONS
`
`.
`
`A Perspective On Batteries For High Power Hearing Instru-
`ments; Dopp et al.; The Hearing Review; Jun. 1996; pp. 42
`and 45.
`Handbook Of Batteries, Second Edition; Linden; 1995;
`entire book.
`
`The Hearing Aid Battery: A Hazard To Elderly Patients;
`Strachanet al.; Age and Aging; 1994; vol. 23; pp. 425-426.
`Design Evolution Of Defibrillator Batteries; Takeuchi; Pro-
`ceedings of The 6th Annual Battery Conference On Appli-
`cations and Advances, Jan. 15-17, 1991; Paper 91BM-1, pp.
`IV-1 to 9.
`
`The Rechargeable Hearing Instrument System; Gitleset al.;
`Hearing Instruments; vol. 38, No. 7, 1987; pp. 3-5.
`Sound Advice; Jul./Aug. 1997; Magnatone; pp. 1-6.
`Sound Advice; Sep./Oct. 1992; Magnatone; pp. 1-6.
`Sound Advice; Nov./Dec. 1997; Magnatone; pp. 1-6.
`Nickel—Metal Hydride Batteries; Leclanch; 1996; Brochure,
`pp. 1 to 6.
`Hearing Aid Battery Sheet; RAYOVAC; Jan. 1995; Bro-
`chure; pp. 1-7.
`Liberty; Magnatone; Apr. 1993; Brochure; pp. 1-7.
`Mineature Rechargeable Batteries; Plainview Batteries; Jul.
`19944; Brochure; pp. 1-6.
`
`* cited by examiner-
`
`2
`
`

`

`U.S. Patent
`
`Oct. 30, 2001
`
`Sheet 1 of 14
`
`US 6,310,960 B1
`
`NNNNN1NNNNNNNN\“
`
`RSS
`Os
`
`3
`
`

`

`U.S. Patent
`
`Oct. 30, 2001
`
`Sheet 2 of 14
`
`US 6,310,960 B1
`
`26a
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`

`

`U.S. Patent
`
`Oct. 30, 2001
`
`Sheet 3 of 14
`
`US 6,310,960 B1
`
`Power(P,pW)
`Current(I,ZA),
`
`0
`
`0.2
`
`0.4
`
`0.6
`
`0.8
`
`1.0
`
`1.2
`
`1.4
`
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`
`OutputVoltage (V)
`
`FIG.3
`
`4.0
`
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`
`2g
`$s 2.0
`>
`
`1.0
`
`° 0
`
`64
`
`66
`
`10
`
`t (hours)
`
`20
`
`30
`
`FIG.4
`
`5
`
`

`

`U.S. Patent
`
`Oct. 30, 2001
`
`Sheet 4 of 14
`
`US 6,310,960 B1
`
`‘\
`
`3p;
`
`l4b
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`22b,23b,
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`

`U.S. Patent
`
`Oct. 30, 2001
`
`Sheet 5 of 14
`
`US 6,310,960 B1
`
`7
`
`

`

`U.S. Patent
`
`Oct. 30, 2001
`
`Sheet 6 of 14
`
`US 6,310,960 B1
`
`0
`
`500
`
`1000
`
`1500
`
`2000
`
`2500
`
`(%)
`
`
`EnergyTransferEfficiency
`
`
`DC - DC Converter Load @ 1.30 V (uA)
`
`FIG.S
`
`8
`
`

`

`U.S. Patent
`
`Oct. 30, 2001
`
`Sheet 7 of 14
`
`US 6,310,960 B1
`
`I64
`
`IG2
`
`170
`
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`
`(70
`
`I66
`
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`
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`
`9
`
`

`

`U.S. Patent
`
`Oct. 30, 2001
`
`Sheet 8 of 14
`
`US 6,310,960 B1
`
`164,168
`
`170
`
`172
`
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`
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`
`162,168
`
`170
`
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`
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`
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`
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`
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`
`FIG.
`
`0
`
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`
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`
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`
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`
`

`

`U.S. Patent
`
`Oct. 30, 2001
`
`Sheet 9 of 14
`
`US 6,310,960 B1
`
`
`
`I62a
`
`i66a
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`
`1780
`
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`
`11
`
`

`

`Sheet 10 of 14
`
`US 6,310,960 B1
`
`U.S. Patent
`
`Oct. 30, 2001
`
`Lf=Cre
`
`12
`
`12
`
`

`

`U.S. Patent
`
`Oct. 30, 2001
`
`Sheet 11 of 14
`
`US 6,310,960 B1
`
`
`
`FIG.16
`
`I64b
`
`I66b
`
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`
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`
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`
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`
`13
`
`

`

`U.S. Patent
`
`Oct. 30, 2001
`
`Sheet 12 of 14
`
`US 6,310,960 B1
`
`\78b
`
`I80b
`
`I60b
`
`
`i66b
`
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`
`14
`
`14
`
`

`

`U.S. Patent
`
`Oct. 30, 2001
`
`Sheet 13 of 14
`
`US 6,310,960 B1
`
`a2
`
`FIG. 2]
`
`15
`
`15
`
`

`

`U.S. Patent
`
`Oct. 30, 2001
`
`Sheet 14 of 14
`
`US 6,310,960 B1
`
`ae
`
`224
`
`236
`
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`
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`
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`
`16
`
`16
`
`

`

`US 6,310,960 B1
`
`1
`RECHARGEABLE HEARING AID SYSTEM
`
`This application is a Divisional of Ser. No. 08/942,963
`filed Feb. 23, 1998.
`
`BACKGROUND OF THE INVENTION
`
`invention relates to hearing aids. More
`The present
`particularly, it may relate to a hearing aid system that may
`comprise a charger and a rechargeable hearing aid; wherein
`the hearing aid may be optically or inductively recharged.
`The rechargeable hearing aid may utilize any conven-
`tional rechargeable battery. However, preferably,
`the
`rechargeable hearing aid may utilize a high energy recharge-
`able battery that may comprise at least one high energy
`rechargeable cell, such as:
`(a) a NiMH (nickel metal-
`hydride) rechargeable cell; or (b) a lithium based recharge-
`able cell.
`
`As used herein, the generic term “lithtum based recharge-
`able cell (or battery)’ may be defined as an aqueous or
`non-aqueous cell or battery in which at least one of the
`Faradaic half cell reactions includeslithium ionsas reactants
`and/or products. In this context, non-aqueous meansthat the
`electrolyte does not contain a significant amountof water. In
`addition, as used herein, the “lithium based rechargeablecell
`(or battery)” may be classified as either a lithium recharge-
`able cell (or battery) (i.e., one having a lithium metal or a
`lithium alloy anode); oras a lithium-ion rechargeable cell (or
`battery) (ie., one having no significant amounts of metallic
`lithium in its anode). Further, the lithium based rechargeable
`cell (or battery) may havea solid electrolyte in the form of
`a polymeror gel; and the lithium-ion rechargeable cell (or
`battery) may have either a liquid electrolyte, or a solid
`electrolyte in the form of a polymerorgel. In this context,
`the polymer electrolyte may be either a true polymer, or the
`polymer maybeplasticized or gelled with the addition of at
`least one low molecular weight organic liquid.
`The materials and the chemical reactions in the high
`energy NiMH and lithium based rechargeable cells and
`batteries described herein are all conventional.
`
`However, each improved, high energy, rechargeable bat-
`tery that is described herein may have a novel cell stack
`design for maximizing the surface area of its cathode and
`anode, to reduce the battery’s impedance, while simulta-
`neously minimizing the battery’s overall size or volume. The
`rechargeable hearing aid may be provided with a DC to DC
`voltage regulating circuit to help match the high energy
`rechargeable battery’s output voltage the input voltage
`required by the hearing aid’s audio amplifier and related
`circuitry, and to help provide high current during transients
`due to loud sounds.
`
`SUMMARYOF THE INVENTION
`
`In the United States alone, about five to eight million
`people use hearing aids. The vast majority of those hearing
`aids are powered by disposable batteries. Since disposable
`hearing aid batteries may have, on the average, a life of from
`about one to two weeks,the typical hearing aid user may use
`about 30 disposable batteries per year. As a result, about 150
`million to 240 million disposable hearing aid batteries may
`be used each year in the United States alone.
`However, the use of disposable hearing aid batteries may
`present many major problems. One problem may bethat
`hearing aids using disposable batteries may have exposed
`battery contacts in their battery compartments, in order to
`makeelectrical contact with the disposable batteries. But if
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`55
`
`60
`
`65
`
`2
`those exposed battery contacts become bent or dirty; or if
`they become corroded, such as due to leakage from the
`disposable batteries,
`the hearing aid may not function
`properly, or may not function atall, until costly repairs are
`made.
`
`Another problem with using disposable hearing aid bat-
`teries may be that during replacement of the millions of
`disposable batteries used each year, a great number of the
`hearing aids involved may suffer damageto the hearing aid’s
`battery compartment door, battery contacts, or other com-
`ponents; or the hearing aid may even be completely ruined,
`such as if it
`is accidentally dropped on a hard surface.
`Besides being costly, such damage may also cause the user
`great inconvenience or hardship, by depriving the user of the
`use of the hearing aid until it is repaired or replaced.
`Disposable hearing aid batteries may also be a problem in
`that they may cause substantial difficulty and stress to the
`elderly, who constitute the vast majority of the users of
`hearing aids, and who may lack the manual dexterity, visual
`acuity, or skill needed to be able to easily replace the hearing
`aid batteries on their own.
`
`A further problem with disposable hearing aid batteries is
`that they may cause adverse environmental consequences
`unless they are properly disposed of.
`Disposable hearing aid batteries may also be a problem in
`that they are relatively costly. They are not only relatively
`costly to purchase, but they may also berelatively costly to
`properly dispose of when expended,
`in order to avoid
`adverse environmental consequences.
`A further problem presented by disposable hearing aid
`batteries may bethat the millions of disposable batteries that
`are discarded each year may present millions of chances
`each year for a small child to harm himself, or herself, by
`accidentally swallowing the battery, or by inserting it into
`his or her nose orear.
`
`Conventional rechargeable hearing aids using recharge-
`able NiCd (nickel cadmium) batteries have not been a
`commercial success, despite the relatively low cost of such
`batteries and their ability to deliver the high current pulses
`that may be required by hearing aids.
`The lack of commercial success may be due to the fact
`that there may be many problems with conventional hearing
`aids using NiCd rechargeable batteries. One problem may be
`that such rechargeable hearing aids may have external
`electrical contacts for receiving electrical energy from an
`external power supply to recharge the NiCd battery. Such
`external electrical contacts may be prone to poor
`performance, or even failure, due to becoming dirty or
`corroded since the hearing aid may be exposed to harsh
`environmental factors, such as the user’s perspiration.
`A further problem with using rechargeable NiCd batteries
`in hearing aids may bethat although rechargeable NiCd
`hearing aid batteries have been made small enough for BTE
`(behind the ear) and for some ITE (in the ear) hearing aids,
`it has not been possible to produce commercially successful,
`highly miniaturized rechargeable NiCd batteries suitable for
`use in the highly popular ITC (in the canal) and CIC
`(completely in the canal) hearing aids. This is because a
`conventional NiCd hearing aid battery that was small
`enoughto fit in an ITC or CIC hearing aid would likely not
`store enough energy to provide the hearing aid with a
`sufficient number of hours of use between charges.
`Using rechargeable NiCd hearing aid batteries may also
`be a problem in that they may havea relatively short cycle
`life (i.e., the numberof times the battery can go throughits
`discharge/recharge cycle). For example, although the cycle
`
`17
`
`17
`
`

`

`US 6,310,960 B1
`
`3
`life of a NiCd hearing aid battery may vary widely depend-
`ing on how it is used and recharged, it may have a usefullife
`of only a few hundred cycles, or less, before its energy
`storage capacity becomes too small to be satisfactory. As a
`result, rechargeable NiCd hearing aid batteries may need to
`be replaced more frequently than may be desirable, since an
`ideal rechargeable hearing aid battery would have a cycle
`life sufficient for it to last the normal expected life of the
`hearing aid with which it is used.
`In addition, rechargeable NiCd hearing aid batteries may
`have the further problem of suffering from a loss in their
`energy storage capacity after they have been in use for a
`while, due to what is knownas their discharge “memory”.
`Thatis, if a rechargeable NiCd hearing aid battery is only
`partially discharged before being recharged, the result may
`bethat it is only possible to discharge the battery to its earlier
`partial discharge point, rather than it being possible to
`discharge the battery to the full discharge capacity it had
`when it was new.
`
`Another problem with rechargeable NiCd hearing aid
`batteries may be that they have a relatively low energy
`capacity per unit volume. This meansthat such batteries may
`have an insufficient capacity to store a given, needed amount
`of energy, particularly if they are to be used in ITC or CIC
`hearing aids.
`Turning now to the present invention, one of its aspects
`may be to provide a rechargeable hearing aid system that
`does not need any electrical contacts on the external surface
`of the hearing aid in order to recharge the hearing aid’s
`rechargeable battery. Accordingly, the rechargeable hearing
`aid system of the present invention may comprise an optical
`charger that may be optically coupled to an optically
`rechargeable hearing aid having a rechargeable battery;
`wherein energy may betransferred from the optical charger
`to the optically rechargeable hearing aid by the use of light,
`rather than by the use of electrical contacts.
`The optical charger may comprise a light source and a
`hearing aid holder. The optically rechargeable hearing aid
`may comprise a housing having a window thatis transparent
`to the light emitted by the light source (such as visible or
`infrared (IR) light, for example); and may further comprise
`a photovoltaic cell for converting the light received from the
`light source into electrical energy for recharging the hearing
`aid’s rechargeable battery. The charger’s hearing aid holder
`may hold the hearing aid in such a waythat the light source
`and the photovoltaic cell are properly positioned with
`respect to each other during the recharging process.
`As is known, many CIC hearing aids may have a draw-
`string to help enable the user to easily remove the hearing
`aid from his or her ear when desired.
`
`Accordingly, one aspect of the present invention may be
`to provide an optically rechargeable hearing aid that may
`further comprise an optical fiber: (a) that may serve as a
`draw string for helping to remove the hearing aid from the
`user’s ear; and/or (b) that may serve as a conduit for helping
`to transport light from the charger’s light source to the
`hearing aid’s photovoltaic cell.
`invention may be to
`A further aspect of the present
`provide an optically rechargeable hearing aid that comprises
`a photovoltaic cell having output voltage, output current,
`and output powercurvesthat are highly suited for recharging
`the high energy NiMH and lithium based rechargeable
`batteries that are described herein.
`
`Anotheraspect of the present invention may beto provide
`an alternative, non-optical, hearing aid system that also does
`not need any electrical contacts on the external surface of the
`
`4
`hearing aid in order to recharge the hearing aid’s recharge-
`able battery. Accordingly, the rechargeable hearing aid sys-
`tem of the present invention may comprise an inductive
`charger that may be inductively coupled to an inductively
`rechargeable hearing aid having a rechargeable battery;
`wherein energy may be transferred from the charger to the
`hearing aid by the use of inductive transfer, rather than by
`the use of electrical contacts.
`
`The inductive charger may comprise an inductive trans-
`mitting circuit and a hearing aid holder; while the induc-
`tively rechargeable hearing aid may comprise an inductive
`receiving circuit. During use of such a rechargeable hearing
`aid system, the inductive transmitting and receiving circuits
`may be inductively coupled to each other, to permit electri-
`cal energy from the inductive transmitting circuit to be
`inductively transferred to the inductive receiving circuit.
`Electrical energy induced in the inductive receiving circuit
`may then be used for recharging the hearing aid’s recharge-
`able battery. The charger’s hearing aid holder may hold the
`hearing aid in such a way that the inductive transmitting
`circuit and the inductive receiving circuit are properly
`positioned with respect to each other.
`As was explained above, existing NiCd rechargeable
`batteries for hearing aids suffer numerous drawbacks.
`Accordingly, one aspect of the present invention may be to
`provide a superior, high energy rechargeable battery that
`mayat least partially achieve one or more of the following
`goals, as a minimum, due to such factors as its electrode
`(s)/electrolyte(s) design and its lower recharge voltage limit:
`(a) to have a relatively high energy capacity, i.e., an energy
`capacity sufficient so that the battery need not be recharged
`more than about once per day during normal use of the
`hearing aid; (b) to have a relatively low output impedance,
`to help avoid a drop in the battery’s output voltage when the
`battery is under load, such as when it is connected to the
`hearing aid’s audio amplifier andrelated circuitry; (c) to be
`highly compact, so that it may be small enough for use in
`even ITC and CIC hearing aids; and/or (d) to have a
`relatively long cycle life, 1e., a cycle life of at least about
`1,000 to 1,500 discharge/recharge cycles (equal to at least
`about 3 to 5 years of normal use).
`All of the above goals may beat least partially achieved
`by the use of the novel, high energy, NiMH and lithium
`based rechargeable batteries that are disclosed herein.
`Because of the materials used in them, the NiMH and the
`lithium based rechargeable batteries disclosed herein may
`inherently have an energy capacity per unit of volumethat
`may be several times that of conventional NiCd recharge-
`able hearing aid batteries, especially after numerous
`discharge/recharge cycles.
`The goalof trying to provide a lithium based rechargeable
`battery that has a relatively low impedance may present a
`rather difficult task to achieve, in view ofthe fact that lithium
`based rechargeable batteries may tend to inherently have a
`relatively high impedance, due to the materials used in them.
`This significant problem may beat least partially overcome
`by providing a lithium based rechargeable battery compris-
`ing elements (i.e., a least one anode, cathode, and layer of
`electrolyte), that may have a relatively large surface area
`since, in general, the battery’s impedance may be inversely
`proportional to the surface area of its elements.
`However, providing a lithium based rechargeable battery
`that may have a relatively low impedance (due to its
`elements having a relatively large surface area), seems at
`first blush to be mutually exclusive with the goal of provid-
`ing a lithium based rechargeable battery that may be highly
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`least partially
`compact. This major problem may be at
`overcome by making the battery’s elements into very thin,
`long strips; and by then: (a) alternately folding the strips
`over each other to form a highly compact alternately folded
`cell stack; (b) by forming the strips into a cell sandwich that
`may then be rolled up to form a spiral wrapped (e.,
`jelly-roll) cell stack; or (c) by forming the strips into a cell
`sandwich that may then be accordion folded into a highly
`compact accordion folded cell stack.
`Another goal of the present invention may be to provide
`a remarkably compact lithium based rechargeable battery.
`In particular, the lithium based rechargeable battery 160
`of FIGS. 10-14 12 having an alternately folded cell stack
`172 may have an external volumeofless than about 10 cubic
`centimeters. In addition, the ratio of the area of the battery
`160’s two largest external faces that are at least generally
`parallel to eachother, (e.g., the cover 178 and the base ofthe
`can 163), to the area of the remainderofthe entire external
`surface area of the battery 160 (e.g. the sidewall of the can
`163), may be greater than about 0.5.
`Similarly, the lithium based rechargeable battery 160a of
`FIGS. 13-15 having a spiral wrapped cell stack 198 may
`have an external volume of less than about one cubic
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`centimeter. In addition, the ratio of the area of the battery
`160a’s two largest external faces that are at least generally
`parallel to each other, (e.g., the cover 178a and the base of
`the can 163), to the area of the remainder of the entire
`external surface area of the battery 160a(e.g. the sidewall of
`the can 163a), may be greater than about 0.5.
`Similarly, the lithium based rechargeable battery 160b of
`FIGS. 16-19 having an accordion folded cell stack 216 may
`have an external volume of less than about one cubic
`centimeter. In addition, the ratio of the area of the battery
`160b’s two largest external faces that are at least generally
`parallel to each other, (e.g., the cover 178b and the base of
`the can 1635), to the area of the remainder of the entire
`external surface area of the battery 160b (e.g. the sidewall of
`the can 163b), may be greater than about 0.5.
`Optimum performance of any hearing aid may not be
`achieved unlessit’s audio amplifier and related circuitry are
`provided with a power source having the proper DC output
`voltage and a low output impedance. However, using the
`lithium based rechargeable batteries that are disclosed herein
`may present major problemsif their use in many conven-
`tional hearing aids is attempted.
`One such problem may be that the audio amplifier and
`related circuits of many conventional hearing aids on the
`market today may typically require a relatively constant
`input voltage of about 1.2 volts. But the lithium based
`rechargeable batteries disclosed herein may have output
`voltages in the range of from about 2.0 to about 4.5 volts
`when fully charged; and their output voltages may not be
`constant, since their output voltages may decline with time
`as they are discharged.
`A further problem with using the lithium based recharge-
`able batteries disclosed herein with such conventional hear-
`ing aids is that their audio amplifier and related circuits may
`be designed for a power source with an impedance in the
`range of a few ohmsto a few tens of ohms to meet high
`fidelity goals; while the impedance of the lithrum based
`rechargeable batteries disclosed herein may bein the range
`of from about 5 to about 100 ohms.
`
`Accordingly, an aspect of the present invention maybe to
`provide a suitable DC to DC voltage regulating circuit
`between the lithtum based rechargeable batteries disclosed
`herein and the audio amplifier and related circuitry of the
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`hearing aid in which they may be used. Such a DC to DC
`voltage regulating circuit may serve three tasks simulta-
`neously. First, it may provide the desired output DC voltage
`level, such as 1.2 volts, despite the fact that its input voltage
`from the lithium based rechargeable batteries may be at a
`considerably higher voltage level. Second, it may provide a
`relatively constant output voltage at
`the desired voltage
`level, despite the fact its input voltage from the lithium
`based rechargeable batteries may decline over time as the
`batteries are discharged. Third, it may help to provide a low
`powersupply impedanceto the hearing aid’s audio amplifier
`and related circuitry.
`An aspectof the present invention maybe to provide such
`a DC to DC voltage regulating circuit comprising inductive
`and/or capacitive energy transfer.
`Alternatively, such a DC to DC voltage regulating circuit
`may not be needed if the hearing aid’s rechargeable battery
`comprises a NiMH rechargeable battery having an output
`voltage of about 1.2 volts.
`It should be understood that the foregoing summaryofthe
`present
`invention does not set forth all of its features,
`advantages, characteristics, structures, methods and/or pro-
`cesses; since these and further features, advantages,
`characteristics, structures, methods and/or processes of the
`present invention will be directly or inherently disclosed to
`those skilled in the art to which it pertains by all of the
`disclosures herein.
`
`BRIEF DESCRIPTION OF THE FIGURES
`
`FIG. 1 is a perspective view,partially in cross-section and
`partially broken away,of a first embodimentof the optically
`rechargeable hearing aid system of the present invention;
`FIG. 2 is a perspective view,partially in cross-section and
`partially broken away, of a second embodimentthereof;
`FIG. 3 is a graph illustrating the output of a photovoltaic
`cell that may be used in the optically rechargeable hearing
`aid of the present invention;
`FIG. 4 is a graphillustrating the output of a high energy
`rechargeable lithium-ion battery that may be used in the
`rechargeable hearing aids of the present invention;
`FIG. 5 is a perspective view,partially in cross-section and
`partially broken away, of the inductively rechargeable hear-
`ing aid system of the present invention;
`FIG. 6 is an electrical schematic for the inductive trans-
`
`mitting and receiving circuits thereof;
`FIG. 7 is an electrical schematic of a first embodiment of
`
`a DC to DC voltage regulating circuit, one utilizing induc-
`tive energy transfer, that may be used in the rechargeable
`hearing aids of the present invention;
`FIG. 8 is a graph illustrating certain characteristics of the
`FIG. 7 electrical circuit during operation;
`FIG. 9 is an electrical schematic of a second embodiment
`
`of a DC to DC voltage regulating circuit, one utilizing
`capacitive energy transfer, that may be used in the recharge-
`able hearing aids of the present invention;
`FIG. 10 is a top elevational view, partially broken away,
`of a cathode and an anode that may be used to form an
`alternately folded cell stack that may be utilized in the
`rechargeable batteries for the rechargeable hearing aids of
`the present invention;
`FIG. 11 is a side elevational view,partially broken away,
`of an alternately folded cell stack that may be formed using
`the cathode and anode of FIG. 10;
`FIG. 12 is an exploded perspective view,partially broken
`away, showing the alternately folded cell stack of FIG. 11 as
`part of a rechargeable button cell battery;
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`FIG. 13 is a perspective view, partially broken away,of a
`cell sandwich and an anode rod that may be used to form a
`spiral wrapped cell stack that may be utilized in the
`rechargeable batteries for the rechargeable hearing aids of
`the present invention;
`taken along line
`FIG. 14 is an end elevational view,
`14—14of FIG. 15, of the can of a rechargeable button cell
`battery containing a spiral wrapped cell stack that may be
`formed using the cell sandwich and anode rod of FIG. 13;
`FIG. 15 is an exploded perspective view,partially broken
`away, showing the spiral wrapped cell stack of FIG. 14 as
`part of a rechargeable button cell battery;
`FIG. 16 is an exploded perspective view of a cell sand-
`wich that may be used to form an accordion foldedcell stack
`that may be utilized in the rechargeable batteries for the
`rechargeable hearing aids of the present invention;
`FIG. 17 is an exploded perspective view of a rechargeable
`button cell battery having an accordion folded cell stack
`formed from the FIG. 16 cell sandwich;
`taken along line
`FIG. 18 is an end elevational view,
`18—18 of FIG. 17, of the accordion folded cell stack;
`FIG. 19 is a top elevational view, taken along line 19—19
`of FIG. 17, of the accordion folded cell stack;
`FIG. 20 is a side elevational view of a folding tool that
`may be used to form the accordion folded cell stack of FIGS.
`17-19;
`FIG. 21 is a top elevational view, taken along line 21—21
`of FIG. 20, of the folding tool and the FIG. 16 cell sandwich,
`with the tool’s arms shownrotated to various positions about
`the tool’s post, for clarity; and
`FIG. 22 is an end elevational view,partially broken away,
`taken along line 22—22 of FIG. 21, showing the accordion
`folded cell stack of FIGS. 17-19 being formed by the
`folding tool.
`DESCRIPTION OF THE PREFERRED
`EMBODIMENTS
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`8
`30; a light source 32; a hollow light source holder 33; a
`powersupply 34 forthe light source 32; and an on/off switch
`36 for the power supply 34. Although the charger 12 is
`illustrated as being relatively small and having a generally
`cylindrical shape, it may have any other suitable size and
`shape.
`Instead of the switch 36, the charger 12 mayalternatively
`include sensor/switch circuitry for automatically turning on
`the power supply 34 whenthe hearing aid 10 is placed in the
`holder 28, and for automatically turning off the power
`supply 34 when the hearing aid 10 is removed from the
`holder 28. Any suitable conventional sensor/switch circuitry
`may be used, such as circuitry using a photointerruptor, or
`a magnetic Hall effect sensor.
`The power supply 34 may be supplied with power from
`any suitable external electrical power source. If the power
`from the external electrical power source is not suitable for
`directly powering the light source 32 and any otherelectrical
`components that may comprise a part of the charger 12, then
`the power supply 34 may comprise any conventional elec-
`trical circuitry that may be needed for converting its input
`powerinto the power needed bythe light source 32 and by
`any other electrical components that may comprise a part of
`the charger 12.
`Alternatively, the power supply 34 may comprise at least
`one disposable or rechargeable battery that may be located
`within the charger 12. If the powerdelivered by the battery
`is not suitable for directly powering the light source 32 and
`any other electrical components that may comprise a part of
`the charger 12,
`then the power supply 34 may further
`comprise any conventional electrical circuitry that may be
`needed for converting its input battery powerinto the power
`needed by the light source 32 and any other electrical
`componen