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EP-3843835-B1 - SYSTEM UTILIZING AN OFFSET EXTERNAL MAGNET

EP3843835B1EP 3843835 B1EP3843835 B1EP 3843835B1EP-3843835-B1

Inventors

  • FUNG, WILSON

Dates

Publication Date
20260506
Application Date
20190823

Claims (15)

  1. An apparatus (100) comprising: a cavity (210); and a ferromagnet assembly (220) having a first centroidal axis (222), the ferromagnet assembly (220) configured to be contained within the cavity (210) the ferromagnet assembly (220) comprising: a first portion (230) comprising at least one non-ferromagnetic material; and a second portion (240) comprising at least one ferromagnetic material, the second portion (240) having a second centroidal axis (242) that is offset from the first centroidal axis (222), characterised in that the ferromagnetic assembly (220) is configured to be removable from the cavity (210).
  2. The apparatus (100) of claim 1, wherein the second centroidal axis (242) is parallel to the first centroidal axis (222).
  3. The apparatus (100) of claim 1 or claim 2, wherein the cavity (210) has a third centroidal axis (212) and the ferromagnetic assembly (220) is configured to be contained within the cavity (210) such that the first centroidal axis (222) is coincident with the third centroidal axis (212).
  4. The apparatus (100) of claim 3, wherein the cavity (210) has a right circular cylindrical shape having a first diameter, the third centroidal axis (212) is an axis of symmetry of the cavity (210), the ferromagnet assembly (220) has a right circular cylindrical shape having a second diameter, the second diameter smaller than or equal to the first diameter such that the ferromagnet assembly (220) fits within the cavity (210), and the first centroidal axis (222) is an axis of symmetry of the ferromagnet assembly (220).
  5. The apparatus (100) of claim 4, wherein the cavity (210) has a first height, and the ferromagnet assembly (220) has a second height smaller than or equal to the first height such that the ferromagnet assembly (220) is configured to fit within the cavity (210).
  6. The apparatus (100) of claim 4, wherein the second portion (240) has a right circular cylindrical shape having a third diameter smaller than the second diameter and the second centroidal axis (242) is an axis of symmetry of the second portion (240).
  7. The apparatus (100) of claim 6, wherein the second portion (240) has a height substantially equal to the second height.
  8. The apparatus (100) of any of claims 4 to 6, wherein the first diameter is in a range of 6 millimeters to 14 millimeters, the first height is in a range of 2 millimeters to 12 millimeters, the second diameter is in a range of 6 millimeters to 14 millimeters, the second height is in a range of 2 millimeters to 12 millimeters, and the third diameter is in a range of 2 millimeters to 12 millimeters.
  9. The apparatus (100) of any preceding claim, wherein the at least one non-ferromagnetic material comprises at least one of: plastic, epoxy, ceramic, titanium, aluminum, and a non-ferromagnetic metal.
  10. The apparatus (100) of any preceding claim, wherein the at least one ferromagnetic material has an external magnetic field.
  11. The apparatus (100) of any preceding claim, wherein the cavity (210) and the ferromagnet assembly (220) both have a non-symmetric shape such that the ferromagnet assembly (220) is configured to be contained within the cavity (210) in only one orientation.
  12. The apparatus (100) of any preceding claim, wherein the ferromagnet assembly (220) is configured to substantially fill the cavity (210).
  13. The apparatus (100) of any preceding claim, further comprising a housing (150) defining the cavity (210), the housing (150) comprising a plurality of portions configured to be reversibly and repeatedly separated and rejoined to allow access to the cavity (210) for inserting and/or removing the ferromagnet assembly (220) from the cavity (210).
  14. The apparatus (100) of claim 13, wherein the plurality of portions of the housing (150) comprise a main body and a lid.
  15. The apparatus (100) of claim 13 or claim 14, wherein the plurality of portions of the housing (150) are shaped to define the cavity (210).

Description

BACKGROUND Field The present application relates generally to implantable auditory prostheses, and more specifically systems and methods using magnetic force to transcutaneously mechanically couple an external portion of an auditory prosthesis with an implanted portion of the auditory prosthesis. Description of the Related Art Hearing loss, which may be due to many different causes, is generally of two types, conductive and/or sensorineural. Conductive hearing loss occurs when the normal mechanical pathways of the outer and/or middle ear are impeded, for example, by damage to the ossicular chain or ear canal. Sensorineural hearing loss occurs when there is damage to the inner ear, or to the nerve pathways from the inner ear to the brain. Auditory prostheses of various types are widely used to improve the lives of users. Such devices include, for example, hearing aids, cochlear implants, bone conduction implants, middle ear implants, and electro-acoustic devices. Individuals who suffer from conductive hearing loss typically have some form of residual hearing because the hair cells in the cochlea are undamaged. As a result, individuals suffering from conductive hearing loss might receive an auditory prosthesis that generates mechanical motion of the cochlea fluid instead of a hearing aid based on the type of conductive loss, amount of hearing loss and customer preference. Such prostheses include, for example, bone conduction devices and direct acoustic stimulators. In many people who are profoundly deaf, however, the reason for their deafness is sensorineural hearing loss. Those suffering from some forms of sensorineural hearing loss are unable to derive suitable benefit from auditory prostheses that generate mechanical motion of the cochlea fluid. Such individuals can benefit from implantable auditory prostheses that stimulate nerve cells of the recipient's auditory system in other ways (e.g., electrical, optical, and the like). Cochlear implants are often proposed when the sensorineural hearing loss is due to the absence or destruction of the cochlea hair cells, which transduce acoustic signals into nerve impulses. Auditory brainstem stimulators might also be proposed when a recipient experiences sensorineural hearing loss due to damage to the auditory nerve. US 6 246 911 B1 describes a hearing prothesis comprising a pair of coil assemblies that are intended to be offset or displaced laterally by a predetermined distance to reduce variations in the signal transmission between the internal and external coils. This offset is achieved by locating a magnet at an eccentric position relative to a circular transmitter coil, and fixing said magnet to the transmitter coil with arms. US 6 246 911 B1 also describes another arrangement whereby the magnet of the external component can be selectively moved between different positions relative to its transmitter coil. This is achieved by locating the magnet within an elongate capsule and moving the magnet within the space defined by the elongate capsule. SUMMARY The invention is defined by the independent claim 1 to which reference is now made. Any methods disclosed hereinafter do not form part of the scope of the invention, and are mentioned for illustrative purposes only. In accordance with the invention, there is provided an apparatus which comprises a cavity and a ferromagnet assembly having a first centroidal axis. The ferromagnet assembly is configured to be contained within and removable from the cavity. The ferromagnet assembly comprises a first portion comprising at least one non-ferromagnetic material. The ferromagnet assembly further comprises a second portion comprising at least one ferromagnetic material, the second portion having a second centroidal axis that is offset from the first centroidal axis. The present disclosure includes an apparatus which comprises a housing configured to be placed over a portion of skin of a recipient, the portion of skin overlaying an implanted device. The implanted device comprises an internal inductive communication coil and an internal ferromagnetic material. The apparatus further comprises an external inductive communication coil within the housing. The external inductive communication coil is configured to be in inductive communication with the internal inductive communication coil. The apparatus further comprises an external ferromagnet contained within a cavity of the housing and substantially filling the cavity. The external ferromagnet comprises a ferromagnetic portion and a non-ferromagnetic portion. The ferromagnetic portion is configured to be magnetically attracted to the internal ferromagnetic material. The cavity has a center that defines a line with a center of the external inductive communication coil and the ferromagnetic portion has a center that is offset from the line. The present disclosure also includes a method which comprises providing a sound processor assembly of an auditory prosthesis. The assembly i