(19)
(11)EP 3 389 771 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
04.12.2019 Bulletin 2019/49

(21)Application number: 16784703.7

(22)Date of filing:  11.10.2016
(51)Int. Cl.: 
A61N 1/372  (2006.01)
A61N 1/36  (2006.01)
A61N 1/375  (2006.01)
A61N 1/08  (2006.01)
A61N 1/05  (2006.01)
(86)International application number:
PCT/US2016/056351
(87)International publication number:
WO 2017/105604 (22.06.2017 Gazette  2017/25)

(54)

COCHLEAR IMPLANTS HAVING MRI-COMPATIBLE MAGNET APPARATUS

COCHLEAIMPLANTATE MIT MRT-KOMPATIBLER MAGNETVORRICHTUNG

IMPLANTS COCHLÉAIRES COMPRENANT UN APPAREIL MAGNÉTIQUE COMPATIBLE AVEC L'IRM


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 18.12.2015 WO PCT/US2015/066862

(43)Date of publication of application:
24.10.2018 Bulletin 2018/43

(73)Proprietor: Advanced Bionics AG
8712 Staefa (CH)

(72)Inventors:
  • LEE, Sung, Jin
    Valencia ,CA 91355 (US)
  • WALTER, Jeryle, L.
    Valencia, CA 91354 (US)
  • SMITH, James George, Elcoate
    Santa Clarita, CA 91350 (US)
  • GOMMEL, Uli
    Valencia, CA 91354 (US)
  • REED, Stephanie, M.
    Conshohocken, PA 19428 (US)

(74)Representative: Schwan Schorer & Partner mbB 
Patentanwälte Bauerstrasse 22
80796 München
80796 München (DE)


(56)References cited: : 
EP-A1- 2 853 287
WO-A1-2015/065442
US-A1- 2005 004 629
US-A1- 2010 046 778
US-A1- 2011 224 756
US-A1- 2013 343 588
US-A1- 2014 343 626
WO-A1-2014/164023
US-A- 5 824 022
US-A1- 2009 134 721
US-A1- 2010 046 779
US-A1- 2011 264 172
US-A1- 2014 012 349
US-A1- 2015 025 613
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    BACKGROUND


    1. Field



    [0001] The present disclosure relates generally to the implantable portion of implantable cochlear stimulation (or "ICS") systems.

    2. Description of the Related Art



    [0002] ICS systems are used to help the profoundly deaf perceive a sensation of sound by directly exciting the intact auditory nerve with controlled impulses of electrical current. Ambient sound pressure waves are picked up by an externally worn microphone and converted to electrical signals. The electrical signals, in turn, are processed by a sound processor, converted to a pulse sequence having varying pulse widths, rates, and/or amplitudes, and transmitted to an implanted receiver circuit of the ICS system. The implanted receiver circuit is connected to an implantable electrode array that has been inserted into the cochlea of the inner ear, and electrical stimulation current is applied to varying electrode combinations to create a perception of sound. The electrode array may, alternatively, be directly inserted into the cochlear nerve without residing in the cochlea. A representative ICS system is disclosed in U.S. Patent No. 5,824,022, which is entitled "Cochlear Stimulation System Employing Behind-The-Ear Sound processor With Remote Control" and incorporated herein by reference in its entirety. Examples of commercially available ICS sound processors include, but are not limited to, the Advanced Bionics Harmony™ BTE sound processor, the Advanced Bionics Naida CI Q Series BTE sound processors and the Advanced Bionics Neptune™ body worn sound processor.

    [0003] As alluded to above, some ICS systems include an implantable cochlear stimulator (or "cochlear implant"), a sound processor unit (e.g., a body worn processor or behind-the-ear processor), and a microphone that is part of, or is in communication with, the sound processor unit. The cochlear implant communicates with the sound processor unit and, some ICS systems include a headpiece that is in communication with both the sound processor unit and the cochlear implant. The headpiece communicates with the cochlear implant by way of a transmitter (e.g., an antenna) on the headpiece and a receiver (e.g., an antenna) on the implant. Optimum communication is achieved when the transmitter and the receiver are aligned with one another. To that end, the headpiece and the cochlear implant may include respective positioning magnets that are attracted to one another, and that maintain the position of the headpiece transmitter over the implant receiver. The implant magnet may, for example, be located within a pocket in the cochlear implant housing. The skin and subcutaneous tissue that separates the headpiece magnet and implant magnet is sometimes referred to as the "skin flap," which is frequently 3 mm to 10 mm thick.

    [0004] The magnitude of the retention force between the headpiece magnet and implant magnet is an important aspect of an ICS system. If the force is too low, the headpiece will not remain in place on the head during typical activities. If, on the other hand, the force is too high, the pressure on the skin flap can result is discomfort and tissue necrosis. The magnitude of the retention force is dictated by the strength of the magnets and the distance between the magnets, which is a function of the thickness of the skin flap. The strength of the headpiece magnet is frequently selected during the post-implantation headpiece fitting processes.

    [0005] The present inventors have determined that conventional cochlear implants are susceptible to improvement. For example, the magnets in many conventional cochlear implants are disk-shaped and have north and south magnetic dipoles that are aligned in the axial direction of the disk. Such magnets are not compatible with magnetic resonance imaging ("MRI") systems. In particular, the cochlear implant 10 illustrated in FIG. 1 includes, among other things, a housing 12 and a disk-shaped solid block magnet 14. The implant magnet produces a magnetic field M in a direction that is perpendicular to the patient's skin and parallel to the axis A, and this magnetic field direction is not aligned with, and may be perpendicular to (as shown), the direction of the MRI magnetic field B. The misalignment of the interacting magnetic fields M and B is problematic for a number of reasons. The dominant MRI magnetic field B (typically 1.5 Tesla or more) may demagnetize the implant magnet 14 or generate a significant amount of torque T on the implant magnet 14. The torque T may dislodge the implant magnet 14 from the pocket within the housing 12, reverse the magnet 14 and/or dislocate the cochlear implant 10, all of which may also induce tissue damage. One proposed solution involves surgically removing the implant magnet 14 prior to the MRI procedure and then surgically replacing the implant magnet thereafter.

    [0006] One proposed solution involves the use of freely rotatable ball magnets that create a magnetic field which can rotate, from the aforementioned direction that is perpendicular to the patient's skin, to a direction that is aligned with the direction of the MRI magnetic field B. To that end, and referring to FIG. 2, one proposed implantable magnet apparatus 20 includes a plurality of freely rotatable ball magnets 22 within a case 24. When the magnet apparatus 20 is in very close proximity to an external magnet 26, the ball magnets 22 will align with the external magnet 26 in the manner shown, with the N-S direction of the ball magnets being the same as that of the external magnet. When the external magnet 26 is removed (FIG. 3), the ball magnets 22 will align with one another. The ball magnets 22 will then rotate as necessary in response to the application of the MRI magnetic field, thereby minimizing the torque T, because the MRI magnetic field is far stronger than the attraction between the ball magnets. Turning to FIG. 4, the present inventors have determined that the use of freely rotatable ball magnets 22 is less than optimal because the distance between implanted ball magnets (located within a cochlear implant 28) and the external magnet 26 (located within an external headpiece 30) is so great that the magnetic attraction between the ball magnets is greater than the magnetic attraction between the ball magnets and the external magnet. The N-S direction of the ball magnets 22 is perpendicular to the N-S direction of the external magnet 26. The increased distance, as compared to the distance illustrated in FIG. 3, is a product of, for example, the presence of the implant and headpiece housings and the thickness of the skin flap. The weak magnetic attraction resulting from the misalignment of the magnetic fields prevents the headpiece from properly mounting to the patient's head. One possible solution is to simply increase the size of the external magnet, thereby increasing the strength of the associated magnetic field to the point at which the ball magnets 22 in a cochlear implant will rotate into the orientation illustrated in FIG. 2. The present inventors have determined, however, that the associated increase in the size and weight of the headpiece is undesirable.

    [0007] Another proposed solution is illustrated in FIG. 5. Here, the cochlear implant 32 includes a diametrically magnetized disk-shaped magnet 34 that is rotatable relative to the remainder of the implant about an axis A, and that has a N-S orientation which is perpendicular to the axis A. The external headpiece 36 includes a diametrically magnetized disk-shaped magnet 38 that is not rotatable relative to the remainder of the headpiece. The implanted magnet 34 is able to rotate about the axis A into alignment with the external magnet 38, and is also able to rotate about the axis A into alignment with an MRI magnetic that is perpendicular to the axis A. Turning to FIG. 6, the present inventors have determined that the use of the diametrically magnetized disk-shaped magnet 34 is less than optimal because a dominant magnetic field (e.g., the MRI magnetic field B) that is misaligned by 30° or more may demagnetize the magnet or generate an amount of torque T on the magnet that is sufficient to dislodge or reverse the magnet and/or dislocate the associated cochlear implant.

    [0008] Another issue is associated with those instances where the user does not precisely position the headpiece 38 over the cochlear implant 32. Referring to FIG. 5, when the headpiece 36 is precisely positioned over the cochlear implant 32, the diametrically magnetized implant magnet 34 will simply rotate into alignment with the non-rotatable diametrically magnetized headpiece magnet 38. The magnetic retention force will correspond to that selected during the fitting process. In those instances where the headpiece 36 is not precisely placed over the implant 32, and the implant magnet 34 will rotate into the magnetic alignment as shown in FIG. 6A. The magnetic retention force will not, however, be strong enough to pull the headpiece 36 (and its antenna) into alignment over the implant 32 (and its antenna). Moreover, even if the headpiece 36 eventually moves to the aligned position over the implant 32, the electronic lock between the sound processor unit and the cochlear implant will be based on the misaligned position.

    [0009] WO 2014/164023 A1 relates to a cochlear implant with an implantable magnet carried within an internal magnet pocket of a flexible implant housing. The internal magnet pocket is made of elastic material and has a magnet aperture through which the magnet may be inserted into or removed from the pocket by using an appropriate tool. US 2011/224756 A1 relates to a cochlear implant with an antenna case including a plurality of freely rotatable spherical magnets or a single cylindrical magnet rotatable around its longitudinal axis. US 2009/134721 A1 relates to an electromagnetic transducer with an antenna case including and one or more spherical magnets, which are freely rotatable and also moveable along an axis.

    SUMMARY



    [0010] The invention relates to a cochlear implant as defined in claim 1. A system in accordance with the present invention includes such a cochlear implant and an external device. The external device may include an antenna and an external magnet.

    [0011] Further aspects and preferred embodiments are defined in the appended claims. Aspects, embodiments and examples of the present disclosure which do not fall under the scope of the appended claims do not form part of the invention and are merely provided for illustrative purposes.

    [0012] There are a number of advantages associated with such apparatus. For example, a strong magnetic field, such as an MRI magnetic field, will not demagnetize the magnet apparatus. Nor will it generate a significant amount of torque on the magnet apparatus and associated cochlear implant. As a result, surgical removal of the cochlear implant magnet prior to an MRI procedure, and then surgically replacement thereafter, is not required. Moreover, in the absence of the strong magnetic field, the magnetic attraction between rotatable magnets in the magnet apparatus will not cause the magnets to rotate into an undesirable N-S orientation.

    [0013] The above described and many other features of the present invention will become apparent as the invention become better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings.

    BRIEF DESCRIPTION OF THE DRAWINGS



    [0014] Detailed descriptions of the exemplary embodiments will be made with reference to the accompanying drawings.

    FIG. 1 is a plan view showing a conventional cochlear implant in an MRI magnetic field.

    FIG. 2 is a partial section view of a conventional implant magnet apparatus and external magnet.

    FIG. 3 is a partial section view of a conventional implant magnet apparatus.

    FIG. 4 is a partial section view of a headpiece and an implanted cochlear implant with a conventional implant magnet apparatus.

    FIG. 5 is a partial section view of a headpiece and an implanted cochlear implant with a conventional implant magnet apparatus.

    FIG. 6 is a partial section view of the implanted cochlear implant with a conventional implant magnet apparatus illustrated in FIG. 5 in an MRI magnetic field.

    FIG. 6A is a partial section view of the implanted cochlear implant and headpiece illustrated in FIG. 5 with the headpiece misaligned.

    FIG. 7 is a perspective view of an implant magnet apparatus in accordance with one embodiment of a present invention.

    FIG. 8 is a perspective view of a portion of the implant magnet apparatus illustrated in FIG. 7.

    FIG. 9 is a diagrammatic view of a system including the magnet apparatus illustrated in FIG. 7 and a headpiece.

    FIG. 9A is a diagrammatic view of a system including the magnet apparatus illustrated in FIG. 7 and a misaligned headpiece.

    FIG. 10 is an exploded view of the implant magnet apparatus illustrated in FIG. 7.

    FIG. 11 is an end view of a portion of the implant magnet apparatus illustrated in FIG. 7.

    FIG. 12 is a perspective view of a portion of the implant magnet apparatus illustrated in FIG. 7.

    FIG. 13 is a plan view of a portion of the implant magnet apparatus illustrated in FIG. 7.

    FIG. 14 is a section view taken along line 14-14 in FIG. 7.

    FIG. 14A is a section view showing a portion of the implant magnet apparatus illustrated in FIG. 14 in a different orientation.

    FIG. 15 is a section view similar to FIG. 14 with the implant magnet apparatus in an MRI magnetic field.

    FIG. 16 is a perspective view of an implant magnet apparatus in accordance with one embodiment of a present invention.

    FIG. 17 is a section view taken along line 17-17 in FIG. 16.

    FIG. 18 is an exploded view of the implant magnet apparatus illustrated in FIG. 16.

    FIG. 18A is an enlarged portion of the section view illustrated in FIG. 17.

    FIG. 18B is an enlarged portion of the section view illustrated in FIG. 17.

    FIG. 19 is a perspective view of a portion of an implant magnet apparatus.

    FIG. 20 is an end view of the portion of an implant magnet apparatus illustrated in FIG. 19.

    FIG. 21 is a perspective view of an implant magnet apparatus in accordance with one embodiment of a present invention.

    FIG. 22 is a perspective view of a portion of the implant magnet apparatus illustrated in FIG. 21.

    FIG. 23 is a perspective view of a portion of the implant magnet apparatus illustrated in FIG. 21.

    FIG. 24 is a plan view of a portion of the implant magnet apparatus illustrated in FIG. 21.

    FIG. 25 is a section view taken along line 25-25 in FIG. 21.

    FIG. 26 is a perspective view of an implant magnet apparatus in accordance with one embodiment of a present invention.

    FIG. 27 is a perspective view of a portion of the implant magnet apparatus illustrated in FIG. 26.

    FIG. 28 is a perspective view of a portion of the implant magnet apparatus illustrated in FIG. 26.

    FIG. 29 is a section view taken along line 29-29 in FIG. 26.

    FIG. 30 is a plan view of a cochlear implant in accordance with one embodiment of a present invention.

    FIG. 31 is a block diagram of a cochlear implant system in accordance with one embodiment of a present invention.


    DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS



    [0015] The following is a detailed description of the best presently known modes of carrying out the inventions. This description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the inventions.

    [0016] As illustrated for example in FIGS. 7 and 8, an exemplary magnet apparatus 100 includes a case 102, with base 104 and a cover 106, a magnet frame 108, and a plurality of elongate diametrically magnetized magnets 110 within the frame that define a N-S direction. The magnet apparatus 100 may, in some instances, be employed a system 50 (FIG. 9) that includes a cochlear implant 200 (described below with reference to FIG. 30) with the magnet apparatus 100 and an external device such as a headpiece 400 (described below with reference to FIG. 31). The headpiece 400 includes, among other things, a housing 402 and a diametrically magnetized disk-shaped positioning magnet 410 that is not rotatable relative to the housing.

    [0017] The exemplary case 102 is disk-shaped and defines a central axis A1, which is also the central axis of the magnet frame 108. The magnet frame 108 is freely rotatable relative to the case 102 about the central axis A1 over 360°. The magnets 110 rotate with the magnet frame 108 about the central axis A1. Each magnet 110 is also freely rotatable relative to the magnet frame 108 about its own longitudinal axis A2 over 360°. As used herein, the phrase "freely rotatable about an axis" refers to an object that can rotate about an axis relative to an adjacent object, albeit with some friction between the two object, without mechanical limitation of the rotation (e.g., with a stop or biasing device that opposes the rotation). In the illustrated implementation, the longitudinal axes A2 are parallel to one another and are perpendicular to the central axis A1.

    [0018] Given the ability of each magnet 110 to freely rotate about its longitudinal axis A2, the magnets 110 align with one another in the N-S direction in the absence of a relatively strong external magnetic field (e.g., the MRI magnetic field discussed above), and the at rest N-S orientation of the magnets 110 will be perpendicular to the central axis A1, as is illustrated in FIGS. 9 and 14. So oriented, the magnetic fields of the diametrically magnetized magnets 110 are aligned with the magnetic field of the diametrically magnetized disk-shaped positioning magnet 410.

    [0019] It should also be noted here that the magnetic field of the positioning magnet 410 is not strong enough to cause the magnets 110 to rotate out of the illustrated at rest N-S orientation. Although the frame 108 will rotate as necessary, the magnets 110 will remain in the N-S orientation illustrated in FIG. 9 and will continue to function as a magnetic unit in the presence of a headpiece magnet. As a result, when the associated headpiece is initially misaligned in the manner illustrated in FIG. 9A, the magnetic retention force will be strong enough to pull the headpiece 400 (and its antenna) into alignment over the implant 200 (and its antenna).

    [0020] The exemplary case 102 is not limited to any particular configuration, size or shape. In the illustrated implementation, the case 102 is a two-part structure that includes the base 104 and the cover 106 which are secured to one another in such a manner that a hermetic seal is formed between the cover and the base. Suitable techniques for securing the cover 106 to the base 104 include, for example, seam welding with a laser welder. With respect to materials, the case 102 (as well as the cases 102b and 102c described below with reference to FIGS. 21-29) may be formed from biocompatible paramagnetic metals, such as titanium or titanium alloys, and/or biocompatible non-magnetic plastics such as polyether ether ketone (PEEK), low-density polyethylene (LDPE), high-density polyethylene (HDPE), ultra-high-molecular-weight polyethylene (UHMWPE), polytetrafluoroethylene (PTFE) and polyamide. In particular, exemplary metals include commercially pure titanium (e.g., Grade 2) and the titanium alloy Ti-6AI-4V (Grade 5), while exemplary metal thicknesses may range from 0.20 mm to 0.25 mm. With respect to size and shape, the case 102 may have an overall size and shape similar to that of conventional cochlear implant magnets so that the magnet apparatus 100 can be substituted for a conventional magnet in an otherwise conventional cochlear implant. In some implementations, the diameter that may range from 9 mm to 16 mm and the thickness may range from 1.5 mm to 3.0 mm. The diameter of the case 102 is 12.9 mm, and the thickness is 2.4 mm, in the illustrated embodiment.

    [0021] Although the present inventions are not limited to any particular number, there are four elongate diametrically magnetized magnets 110 in the exemplary magnet apparatus 100. Two of the otherwise identical magnets 110 are relatively long and two are relatively short in order to efficiently utilize the available volume within the case 102, as is best shown in FIG. 8. Turning to FIGS. 10-12, the exemplary magnets 110 are non-circular in a cross-section that is perpendicular to the longitudinal axis A2 and, in the illustrated implementation, include curved surfaces 112 and flat surfaces 114. The magnet width WM, which extends in the N-S direction, is greater than the magnet thickness TM, which extends in a direction perpendicular to the N-S direction. The use of elongate diametrically magnetized magnets that are larger in the N-S direction than in the direction perpendicular thereto reduces the likelihood of magnet damage, as is discussed in greater detail below with reference to FIG. 14. Nevertheless, in other implementations, the cross-sectional shape may be circular. The magnet lengths LM of the relatively long and short magnets 110, i.e. the length in the direction of axis A2, are greater than the magnet width WM and magnet thickness TM. Suitable materials for the magnets 110 include, but are not limited to, neodymium-boron-iron and samarium-cobalt.

    [0022] As illustrated in FIGS 10 and 13, the exemplary magnet frame 108 includes a disk 116 and a plurality of magnet receptacles 118 that extend completely through the disk and define walls 119 that are located between adjacent magnets 110. Two of the otherwise identical magnet receptacles 118 are relatively long and two are relatively short. The magnet receptacles 118, which are rectangular in shape, have receptacle lengths LR that are substantially equal to (i.e., about 50-100 µm greater than) the magnet lengths LM, and receptacle widths WR that are substantially equal to (i.e., about 25-50 µm greater than) the magnet widths WM. The receptacle thicknesses TR, one the other hand, are substantially greater than (i.e., about 100-200 µm greater than) the magnet thicknesses TM. The use of a magnet receptacle that is thicker than the magnet reduces the likelihood of magnet damage, as is discussed in greater detail below with reference to FIG. 14. In those instances where the apparatus includes magnets with circular cross-sections, similar magnet protection functionality can be achieved by employing a frame that is thicker than the magnet diameter. Suitable materials for the frame 108 (as well as the frames 108b and 108c described below with reference to FIGS. 21-29), which may be formed by machining or injection molding, include paramagnetic metals, polymers and plastics such as those discussed above in the context of the case 102.

    [0023] As illustrated for example in FIG. 14, absent a dominant MRI magnetic field B, the magnets 110 will remain aligned with one another in the N-S direction and the N-S orientation of the magnets will be perpendicular to the central axis A1 of the case 102. So oriented, the flat surfaces 114 of the magnets 110 will be aligned with one another, will be perpendicular to the central axis A1 and will face the inner surface 120 of the case 102. The N-S orientation of the magnets 110 remains the same, i.e. perpendicular to the central axis A1, both when the external diametrically magnetized disk-shaped positioning magnet 410 is present (FIG. 9) and when it is not (FIG. 14).

    [0024] A gap G, resulting from the difference in receptacle thicknesses TR and magnet thicknesses TM, is located between one of the flat surfaces 114 of each magnet and the inner surface 120 of the case 102 that the flat surface faces. The gap G protects the magnets 110, especially those formed from somewhat brittle ceramic materials, from impacts to the exterior surface of case 102. For example, when the magnet apparatus 100 is oriented in the manner illustrated in FIG. 14 and is impacted by a force F1, the deflection of the case 102 (if any) into the magnet receptacle 118 will not be large enough for the inner surface 120 to impact the adjacent magnet surface 114. If, on the other hand, a force F2 causes deflection of a portion of the case 102 into the magnet receptacle 118, the magnet 110 will slide into the gap G. In both instances, impact on the magnets 100 is minimized. Turning to FIG. 14A, it should be noted that the magnets 110 need not be posited such that one of the flat surfaces 114 is in contact with an inner surface 120 of case 102 to benefit from the gap G. Here, due to the position of the magnet 110, both of the flat surfaces 114 are located adjacent to a portion of the now-split gap G shown in FIG. 14. Accordingly, in those instances where deflection of the case 102 due to force F3 is sufficient to cause the inner surface 120 to come into contact with the adjacent flat surface 114, the magnet 110 can move into the portion of the gap adjacent to the opposite flat surface 114 to prevent magnet damage.

    [0025] Turning to FIG. 15, when exposed to a dominant MRI magnetic field B, the torque T on the magnets 110 will rotate the magnets about their axis A2 (FIG. 8), thereby aligning the magnetic fields of the magnets 110 with the MRI magnetic field B. The magnet frame 108 will also rotate about axis A1 as necessary to align the magnetic fields of the magnets 110 with the MRI magnetic field B. When the magnet apparatus 100 is removed from the MRI magnetic field B, the magnetic attraction between the magnets 110 will cause the magnets to rotate about axis A2 back to the orientation illustrated in FIG. 14, where they are aligned with one another in the N-S direction and the N-S orientation of the magnets is perpendicular to the central axis A1 of the case 102.

    [0026] To facilitate rotation of the magnet frame 108 and/or the magnets 110, lubricious friction reducing material may be provided between the case 102 and the magnet frame 108 and/or between the magnets 110 and the case 102 and magnet frame 108. For example, the magnet apparatus 100a illustrated in FIGS. 16-18 is substantially similar to the magnet apparatus 100 and similar elements are represented by similar reference numerals. Here, however, a pair of lubricious disks 122 and a lubricious ring 124 formed from PTFE, a hard material (e.g. titanium) with a lubricious coating, or other suitable materials are positioned between the case 102 and the magnet frame 108. Alternatively, instead of two lubricious disks, a single lubricious disk 122 may be positioned on the magnet frame 108 and the portion of the case 102 that will face the external headpiece. In other implementations, a lubricious layer 126 may be added to the inner surface of the case 102 and/or some or all of the various surfaces of the frame 108. The lubricious layer 126 may be in the form of a specific finish of the inner surface that reduces friction, as compared to an unfinished surface, or may be a coating of a lubricious material such as diamond-like carbon (DLC), titanium nitride (TiN), PTFE, polyethylene glycol (PEG), Parylene, fluorinated ethylene propylene (FEP) and electroless nickel sold under the tradenames Nedox® and Nedox PF™. The DLC coating, for example, may be only 0.5 to 5 microns thick. In those instances where the base 104 and a cover 106 are formed by stamping, the finishing process may occur prior to stamping. Micro-balls, biocompatible oils and lubricating powders may also be added to the interior of the case 102 to reduce friction.

    [0027] Alternatively, or in addition, the magnets 110 may be located within tubes 128 formed from low friction material, as is illustrated in FIGS. 19 and 20. Suitable materials for the tube 128 include polymers, such as silicone, PEEK and other plastics, PTFE, and PEEK-PTFE blends, and paramagnet metals. The magnets 110 may be secured to the tubes 128 such that the each tube rotates with the associated magnet about its axis A2, or the magnets may be free to rotate relative to the tubes. The magnet/tube combination is also more mechanically robust than a magnet alone. The magnets 110 may, in place of the tube 128, be coated with the lubricious materials discussed above.

    [0028] Another exemplary magnet apparatus, which is generally represented by reference numeral 100b in FIGS. 21-25, is substantially similar to the magnet apparatus 100 and similar elements are represented by similar reference numerals. To that end, the magnet apparatus 100b includes a case 102b, with a base 104b and a cover 106b, a magnet frame 108b, and a plurality of elongate diametrically magnetized magnets 110b within the frame. The frame 108b does not include a plurality of magnet receptacles and walls 119 (FIGS. 10 and 13) that separate adjacent magnets, as does the frame 108, or any other frame structures that separate the magnets. Instead, the frame 108b includes a disk 116b and a single magnet receptacle 118b that extends completely through the disk. The magnet receptacle 118b is configured to hold all of the magnets 110b (four in the illustrated embodiment) and includes a relatively long portion and two relatively short portions. The magnets 110b are elongate diametrically magnetized magnets that are circular in cross-section, located within low friction tubes 128, and include rounded corners 111b. The magnets 110 with flat surface 114 (described above with reference to FIGS. 19 and 20) may also be employed.

    [0029] In the illustrated implementation, the surfaces of the frame 108b are coated with a lubricious layer 126 (e.g., DLC), while the inner surfaces of the case 102 do not include a lubricious layer. The very thin lubricious layer 126 reduces friction between the case 102 and frame 108b, while the low friction tubes 128 reduce friction between adjacent magnets 110b as well as between the case 102 and the magnets 110b. As such, the aforementioned lubricious disks 122 and a lubricious ring 124 may be omitted, thereby reducing the diameter and thickness of the magnet apparatus 100b as compared to magnet apparatus 100a (FIGS. 16-18). Additionally, although the diameters of the magnets 110b in the exemplary magnet apparatus 100b are equal to the widths of the magnets 110 (FIG. 11) in the exemplary magnet apparatus 100, the omission of the walls 119 between the magnets reduces the overall diameter of the magnet apparatus 100b by an amount ΔD1 (FIG. 25). The diameter of the case 102b is 12.6 mm, and the thickness is 2.9 mm, in the illustrated embodiment.

    [0030] The overall diameter of the magnet apparatus may be further reduced by reducing the number of magnets in the apparatus while maintaining the same magnetic strength by including the same total volume of magnet material. To that end, and referring to FIGS. 26-29, the exemplary magnet apparatus 100c is substantially similar to magnet apparatus 100b and similar elements are represented by similar reference numbers. The magnet apparatus 100c includes a case 102c, with a base 104c and a cover 106c, a magnet frame 108c, and a plurality of elongate diametrically magnetized magnets 110c within the frame. The frame 108c includes a disk 116c and a single magnet receptacle 118c, with a relatively long portion and two relatively short portions, which extends completely through the disk.

    [0031] Here, three magnets 110c with flat portions 114c are located within the magnet receptacle 118c. Low friction tubes 128c cover the magnets 110c. The reduction in the number of magnets reduces the overall diameter of the magnet apparatus 100s, as compared to the magnet apparatus 100b, by an amount ΔD2 (FIG. 29). It should be noted that the widths of the magnets 110c (FIG. 29) are greater than diameters of the magnets 110b (FIG. 25) in order to provide the same volume of magnetic material, which results in a slight increase in the overall thickness of the magnet apparatus 100c as compared to the magnet apparatus 100b. The diameter of the case 102c is 11.6 mm, and the thickness is 3.2 mm, in the illustrated embodiment.

    [0032] One example of a cochlear implant (or "implantable cochlear stimulator") including the present magnet apparatus 100 (or 100a-100c) is the cochlear implant 200 illustrated in FIG. 30. The cochlear implant 200 includes a flexible housing 202 formed from a silicone elastomer or other suitable material, a processor assembly 204, a cochlear lead 206, and an antenna 208 that may be used to receive data and power by way of an external antenna that is associated with, for example, a sound processor unit. The cochlear lead 206 may include a flexible body 210, an electrode array 212 at one end of the flexible body, and a plurality of wires (not shown) that extend through the flexible body from the electrodes 212a (e.g., platinum electrodes) in the array 212 to the other end of the flexible body. The magnet apparatus 100 is located within a region encircled by the antenna 208 (e.g., within an internal pocket 202a defined by the housing 202) and insures that an external antenna (discussed below) will be properly positioned relative to the antenna 208. The exemplary processor assembly 204, which is connected to the electrode array 212 and antenna 208, includes a printed circuit board 214 with a stimulation processor 214a that is located within a hermetically sealed case 216. The stimulation processor 214a converts the stimulation data into stimulation signals that stimulate the electrodes 212a of the electrode array 212.

    [0033] Turning to FIG. 31, the exemplary cochlear implant system 60 includes the cochlear implant 200, a sound processor, such as the illustrated body worn sound processor 300 or a behind-the-ear sound processor, and a headpiece 400.

    [0034] The exemplary body worn sound processor 300 in the exemplary ICS system 60 includes a housing 302 in which and/or on which various components are supported. Such components may include, but are not limited to, sound processor circuitry 304, a headpiece port 306, an auxiliary device port 308 for an auxiliary device such as a mobile phone or a music player, a control panel 310, one or more microphones 312, and a power supply receptacle 314 for a removable battery or other removable power supply 316 (e.g., rechargeable and disposable batteries or other electrochemical cells). The sound processor circuitry 304 converts electrical signals from the microphone 312 into stimulation data. The exemplary headpiece 400 includes a housing 402 and various components, e.g., a RF connector 404, a microphone 406, an antenna (or other transmitter) 408 and a diametrically magnetized disk-shaped positioning magnet 410, that are carried by the housing. The headpiece 400 may be connected to the sound processor headpiece port 306 by a cable 412. The positioning magnet 410 is attracted to the magnet apparatus 100 of the cochlear stimulator 200, thereby aligning the antenna 408 with the antenna 208. The stimulation data and, in many instances power, is supplied to the headpiece 400. The headpiece 400 transcutaneously transmits the stimulation data, and in many instances power, to the cochlear implant 200 by way of a wireless link between the antennae. The stimulation processor 214a converts the stimulation data into stimulation signals that stimulate the electrodes 212a of the electrode array 212.

    [0035] In at least some implementations, the cable 412 will be configured for forward telemetry and power signals at 49 MHz and back telemetry signals at 10.7 MHz. It should be noted that, in other implementations, communication between a sound processor and a headpiece and/or auxiliary device may be accomplished through wireless communication techniques. Additionally, given the presence of the microphone(s) 312 on the sound processor 300, the microphone 406 may be also be omitted in some instances. The functionality of the sound processor 300 and headpiece 400 may also be combined into a single head wearable sound processor. Examples of head wearable sound processors are illustrated and described in U.S. Patent Nos. 8,811,643 and 8,983,102.

    [0036] Although the inventions disclosed herein have been described in terms of the preferred embodiments above, numerous modifications and/or additions to the above-described preferred embodiments would be readily apparent to one skilled in the art. The inventions include any combination of the elements from the various species and embodiments disclosed in the specification that are not already described. It is intended that the scope of the present inventions extend to all such modifications and/or additions and that the scope of the present inventions is limited solely by the claims set forth below.


    Claims

    1. A cochlear implant, comprising:

    a cochlear lead (206) including a plurality of electrodes (212);

    an antenna (208);

    a stimulation processor (214a) operably connected to the antenna and to the cochlear lead; and

    a magnet apparatus (100, 100a, 100b, 100c), associated with the antenna and including a case (102, 102b, 102c) defining a central axis (A1), characterized by the magnet apparatus further comprising a magnet frame (108, 108b, 108c) within the case and rotatable relative to the case about the central axis of the case and a plurality of elongate diametrically magnetized magnets (110, 110b, 110c) that are located in the magnet frame, the magnets defining a longitudinal axis (A2) and a N-S direction and being freely rotatable about the longitudinal axis relative to the magnet frame.


     
    2. A cochlear implant as claimed in claim 1, wherein
    the magnets (110, 110b, 110c) each define a N-S rotational orientation; and
    the magnets are magnetically attracted to one another in such manner that, absent the presence of a dominant magnetic field, the N-S rotational orientation of the magnets is perpendicular to the central axis (A1) of the case (102, 102b, 102c).
     
    3. A cochlear implant as claimed in claim 1, wherein
    the magnets (110, 110b, 110c) each define a length in the direction of the longitudinal axis (A2), a thickness, and a width; and
    the length is greater than the width and the thickness.
     
    4. A cochlear implant as claimed in claim 3, wherein
    the width is greater than the thickness, and wherein
    the width extends in the N-S direction.
     
    5. A cochlear implant as claimed in claim 3, wherein
    the magnets (110, 110c) each define a cross-section, including first and second curved surfaces that are connected to one another by first and second flat surfaces (114), in a plane perpendicular to the longitudinal axis (A2);
    the curved surfaces are separated from one another in the N-S direction; and
    the flat surfaces are separated from one another in a direction perpendicular to the N-S direction.
     
    6. A cochlear implant as claimed in claim 3, wherein
    the magnet frame (108, 108b, 108c) defines a thickness; and
    the thickness of the magnets (110, 110b, 110c) is less than the thickness of the magnet frame, wherein
    the magnet frame includes a plurality of magnet recesses (118, 118b, 118c) defining recess lengths and recess widths, in which the plurality of magnets are located;
    the magnet recess lengths are substantially equal to the magnet lengths; and
    the magnet recess widths are substantially equal to the magnet widths.
     
    7. A cochlear implant as claimed in claim 3, wherein
    at least one of the magnets (110, 110b, 110c) is longer than an adjacent magnet.
     
    8. A cochlear implant as claimed in claim 1, wherein
    the magnets (110, 110c) each define a non-circular cross-section in a plane perpendicular to the longitudinal axis (A2).
     
    9. A cochlear implant as claimed in claim 1, wherein
    the longitudinal axes (A2) of the magnets (110, 110b, 110c) are parallel to one another.
     
    10. A cochlear implant as claimed in claim 1, further comprising:
    lubricious material (122, 124, 126, 128, 128c) between the case (102, 102b, 102c) and the magnet frame (108, 108b, 108c) or between the magnets (110, 110b, 110c) and the magnet frame.
     
    11. A cochlear implant as claimed in claim 1, wherein
    the magnets (110, 110b, 110c) are located within respective tubes (128, 128c) formed from lubricious material.
     
    12. A cochlear implant as claimed in claim 1, wherein
    the magnet frame (108b, 108c) includes a single magnet recess (118b, 118c) in which all of the plurality of magnets (110b, 110c) are located with no portion of the magnet frame located between adjacent magnets, wherein
    the single magnet recess includes a first portion and second and third portions that are shorter than the first portion.
     
    13. A cochlear implant as claimed in claim 1, wherein
    the magnet frame (108, 108b, 108c) includes a lubricious outer layer (126), wherein the case (102, 102b, 102c) defines an inner surface that does not include a lubricious layer or wherein the magnets (110, 110b, 110c) define respective outer surfaces and at least a portion of the outer surfaces of the magnets is covered by lubricious material (126).
     
    14. A system, comprising
    a cochlear implant (200) as claimed in any one of claims 1-13; and
    an external device (400) including a diametrically magnetized disk-shaped positioning magnet (410), wherein
    the external device includes a housing (402) and the positioning magnet is not rotatable relative to the housing.
     
    15. A system, comprising
    a cochlear implant (200) as claimed in any one of claims 1-14; and
    a headpiece (400) including

    an antenna (408), and

    a diametrically magnetized disk-shaped positioning magnet (410) associated with the antenna, wherein the headpiece includes a housing (402) and the positioning magnet is not rotatable relative to the housing.


     


    Ansprüche

    1. Cochlea-Implantat mit:

    einer Cochlea-Zuleitung (206) mit einer Mehrzahl von Elektroden (212);

    einer Antenne (208);

    einem Stimulationsprozessor (214a), der in Wirkverbindung mit der Antenne und der Cochlea-Zuleitung steht; und

    einer Magnetvorrichtung (100, 100a, 100b, 100c), die mit der Antenne assoziiert ist und ein Gehäuse (102, 102b, 102c) aufweist, welches eine zentrale Achse (A1) festlegt, dadurch gekennzeichnet, dass die Magnetvorrichtung ferner einen Magnetrahmen (108, 108b, 108c) innerhalb des Gehäuses aufweist, der relativ zu dem Gehäuse um die zentrale Achse des Gehäuses drehbar ist, sowie eine Mehrzahl von langgestreckten diametral magnetisierten Magneten (110, 110b, 110c) aufweist, die in dem Magnetrahmen angeordnet sind, wobei die Magnete eine Längsachse (A2) und eine N-S Richtung festlegen und frei um die Längsachse relativ zu dem Magnetrahmen drehbar sind.


     
    2. Cochlea-Implantat gemäß Anspruch 1, wobei
    die Magneten (110, 110b, 110c) jeweils eine N-S Drehorientierung festlegen; und
    die Magneten wechselseitig magnetisch so angezogen werden, dass in Abwesenheit eines dominanten Magnetfelds die N-S Drehorientierung der Magneten senkrecht zu der zentralen Achse (A1) des Gehäuses (102, 102b, 102c) steht.
     
    3. Cochlea-Implantat gemäß Anspruch 1, wobei
    die Magneten (110, 110b, 110c) jeweils eine Länge in Richtung der Längsachse (A2), eine Dicke sowie eine Breite festlegen; und
    die Länge größer als die Breite und die Dicke ist.
     
    4. Cochlea-Implantat gemäß Anspruch 1, wobei
    die Breite größer als die Dicke ist und wobei
    sich die Breite in der N-S Richtung erstreckt.
     
    5. Cochlea-Implantat gemäß Anspruch 3, wobei
    die Magneten (110, 110c) jeweils einen Querschnitt, einschließlich erster und zweiter gekrümmter Flächen, die miteinander über erste und zweite flache Flächen (114) verbunden sind, in einer Ebene senkrecht zu der Längsachse (A2) festlegen; die gekrümmten Flächen in der N-S Richtung voneinander getrennt sind; und
    die flachen Flächen in einer Richtung senkrecht zu der N-S Richtung voneinander getrennt sind.
     
    6. Cochlea-Implantat gemäß Anspruch 3, wobei
    der Magnetrahmen (108, 108b, 108c) eine Dicke festlegt; und die
    die Dicke der Magneten (110, 110b, 110c) geringer als die Dicke des Magnetrahmens ist, wobei
    der Magnetrahmen eine Mehrzahl von Magnetaussparungen (118, 118b, 118c) aufweist, die Aussparungslängen und Aussparungsbreiten festlegen und in welchen die Mehrzahl von Magneten angeordnet sind;
    die Magnetausnehmungslängen im Wesentlichen gleich zu den Magnetlängen sind; und
    die Magnetaussparungsbreiten im Wesentlichen gleich den Magnetbreiten sind.
     
    7. Cochlea-Implantat gemäß Anspruch 3, wobei mindestens einer der Magneten (110, 110b, 110c) länger als ein benachbarter Magnet ist.
     
    8. Cochlea-Implantat gemäß Anspruch 1, wobei die Magneten (110, 110b, 110c) einen nicht-kreisförmigen Querschnitt in einer Ebene senkrecht zu der Längsachse (A2) festlegen.
     
    9. Cochlea-Implantat gemäß Anspruch 1, wobei die Längsachsen (A2) der Magneten (110, 110b, 110c) parallel zueinander sind.
     
    10. Cochlea-Implantat gemäß Anspruch 1, ferner versehen mit Schmiermaterial (122, 124, 126, 128, 128c) zwischen dem Gehäuse (102, 102b, 102c) und dem Magnetrahmen (108, 108b, 108c) oder zwischen den Magneten (110, 110b, 110c) und dem Magnetrahmen.
     
    11. Cochlea-Implantat gemäß Anspruch 1, wobei die Magneten (110, 110b, 110c) in jeweiligen aus Schmiermaterial gebildeten Röhren (128, 128c) angeordnet sind.
     
    12. Cochlea-Implantat gemäß Anspruch 1, wobei der Magnetrahmen (108b, 108c) eine einzelne Magnetaussparung (118b, 118c) aufweist, in welcher alle der Mehrzahl von Magneten (110b, 110c) angeordnet sind, wobei kein Teil des Magnetrahmens zwischen benachbarten Magneten angeordnet ist, wobei die einzelne Magnetaussparung einen ersten Abschnitt und zweite und dritte Abschnitte aufweist, die kürzer als der erste Abschnitt sind.
     
    13. Cochlea-Implantat gemäß Anspruch 1, wobei der Magnetrahmen (108, 108b, 108c) eine äußere Schmierschicht (126) aufweist, wobei das Gehäuse (102, 102b, 102c) eine Innenfläche aufweist, die keine Schmierschicht aufweist, oder wobei die Magneten (110, 110b, 110c) jeweilige Außenflächen aufweisen, wobei mindestens ein Teil der Außenflächen der Magnete von Schmiermaterial (126) bedeckt ist.
     
    14. System mit
    einem Cochlea-Implantat (200) gemäß einem der Ansprüche 1 bis 13; sowie einer externen Vorrichtung (400) mit einem diametral magnetisierten scheibenförmigen Positionierungsmagneten (410), wobei die externe Vorrichtung ein Gehäuse (402) aufweist und der Positionierungsmagnet relativ zu dem Gehäuse nicht drehbar ist.
     
    15. System mit
    einem Cochlea-Implantat (200) gemäß einem der Ansprüche 1 bis 14; und einem Kopfstück (400) mit

    einer Antenne (408), und

    einem diametral magnetisierten scheibenförmigen Positionierungsmagneten (410), der mit der Antenne assoziiert ist, wobei das Kopfstück ein Gehäuse (402) aufweist und der Positionierungsmagnet relativ zu dem Gehäuse nicht drehbar ist.


     


    Revendications

    1. Implant cochléaire, comprenant :

    un fil de sortie cochléaire (206) comportant une pluralité d'électrodes (212) ;

    une antenne (208) ;

    un processeur de stimulation (214a) fonctionnellement relié à l'antenne et au fil de sortie cochléaire ; et

    un appareil à aimants (100, 100a, 100b, 100c), associé à l'antenne et comportant un boîtier (102, 102b, 102c) définissant un axe central (A1), caractérisé en ce que l'appareil à aimants comprend en outre un châssis pour aimants (108, 108b, 108c) à l'intérieur du boîtier et rotatif par rapport au boîtier autour de l'axe central du boîtier et une pluralité d'aimants allongés diamétralement magnétisés (110, 110b, 110c) qui se situent dans le châssis pour aimants, les aimants définissant un axe longitudinal (A2) et une direction N-S et pouvant tourner librement autour de l'axe longitudinal par rapport au châssis pour aimants.


     
    2. Implant cochléaire selon la revendication 1, dans lequel
    les aimants (110, 110b, 110c) définissent chacun une orientation en rotation N-S ; et
    les aimants sont magnétiquement attirés les uns vers les autres de telle sorte que, en l'absence d'un champ magnétique dominant, l'orientation en rotation N-S des aimants est perpendiculaire à l'axe central (A1) du boîtier (102, 102b, 102c).
     
    3. Implant cochléaire selon la revendication 1, dans lequel
    les aimants (110, 110b, 110c) définissent chacun une longueur dans la direction de l'axe longitudinal (A2), une épaisseur, et une largeur ; et
    la longueur est plus grande que la largeur et l'épaisseur.
     
    4. Implant cochléaire selon la revendication 3, dans lequel
    la largeur est plus grande que l'épaisseur, dans lequel
    la largeur s'étend dans la direction N-S.
     
    5. Implant cochléaire selon la revendication 3, dans lequel
    les aimants (110, 110c) définissent chacun une section transversale, comportant des première et deuxième surfaces incurvées qui sont reliées l'une à l'autre par des première et deuxième surfaces plates (114), dans un plan perpendiculaire à l'axe longitudinal (A2) ;
    les surfaces incurvées sont séparées l'une de l'autre dans la direction N-S ; et
    les surfaces plates sont séparées l'une de l'autre dans une direction perpendiculaire à la direction N-S.
     
    6. Implant cochléaire selon la revendication 3, dans lequel
    le châssis pour aimants (108, 108b, 108c) définit une épaisseur ; et
    l'épaisseur des aimants (110, 110b, 110c) est inférieure à l'épaisseur du châssis pour aimants, dans lequel
    le châssis pour aimants comporte une pluralité d'encoches pour aimant (118, 118b, 118c) définissant des longueurs d'encoche et des largeurs d'encoche, dans lesquelles se situe la pluralité d'aimants ;
    les longueurs d'encoche pour aimant sont sensiblement égales aux longueurs d'aimant ; et
    les largeurs d'encoche pour aimant sont sensiblement égales aux largeurs d'aimant.
     
    7. Implant cochléaire selon la revendication 3, dans lequel
    au moins un des aimants (110, 110b, 110c) est plus long qu'un aimant adjacent.
     
    8. Implant cochléaire selon la revendication 1, dans lequel
    les aimants (110, 110c) définissent chacun une section transversale non circulaire dans un plan perpendiculaire à l'axe longitudinal (A2).
     
    9. Implant cochléaire selon la revendication 1, dans lequel
    les axes longitudinaux (A2) des aimants (110, 110b, 110c) sont parallèles les uns aux autres.
     
    10. Implant cochléaire selon la revendication 1, comprenant en outre :
    un matériau lubrifiant (122, 124, 126, 128, 128c) entre le boîtier (102, 102b, 102c) et le châssis pour aimants (108, 108b, 108c) ou entre les aimants (110, 110b, 110c) et le châssis pour aimants.
     
    11. Implant cochléaire selon la revendication 1, dans lequel
    les aimants (110, 110b, 110c) se situent à l'intérieur de tubes respectifs (128, 128c) formés à partir d'un matériau lubrifiant.
     
    12. Implant cochléaire selon la revendication 1, dans lequel
    le châssis pour aimants (108b, 108c) comporte une unique encoche pour aimants (118b, 118c) dans laquelle se situent tous les aimants de la pluralité d'aimants (110b, 110c) sans aucune partie du châssis pour aimants située entre aimants adjacents, dans lequel
    l'unique encoche pour aimants comporte une première partie et des deuxième et troisième parties qui sont plus courtes que la première partie.
     
    13. Implant cochléaire selon la revendication 1, dans lequel
    le châssis pour aimants (108, 108b, 108c) comporte une couche externe lubrifiante (126), dans lequel le boîtier (102, 102b, 102c) définit une surface interne qui ne comporte pas de couche lubrifiante ou dans lequel les aimants (110, 110b, 110c) définissent des surfaces externes respectives et au moins une partie des surfaces externes des aimants est recouverte par un matériau lubrifiant (126).
     
    14. Système, comprenant
    un implant cochléaire (200) selon l'une quelconque des revendications 1 à 13 ; et
    un dispositif externe (400) comportant un aimant de positionnement en forme de disque diamétralement magnétisé (410), dans lequel
    le dispositif externe comporte un boîtier (402) et l'aimant de positionnement ne peut pas tourner par rapport au boîtier.
     
    15. Système, comprenant
    un implant cochléaire (200) selon l'une quelconque des revendications 1 à 14 ; et
    une pièce à main (400) comportant

    une antenne (408), et

    un aimant de positionnement en forme de disque diamétralement magnétisé (410) associé à l'antenne, la pièce à main comportant un boîtier (402) et l'aimant de positionnement ne pouvant pas tourner par rapport au boîtier.


     




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    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description