Magnet arrangement for bone conduction hearing implant
An implantable magnetic transducer arrangement is described for a hearing implant in a recipient patient. An implant housing hermetically encapsulates an interior housing volume and is fixedly attached to skull bone beneath the skin of the patient. A magnetic transducer is located within the housing volume and includes multiple permanent magnets wherein adjacent magnets have opposite magnetic polarities, and one or more suspension elements that resiliently couple adjacent magnets to allow their relative movement. The magnetic transducer forms a coupled oscillating system with an external magnetic drive component above the skin of the patient to develop a mechanical stimulation signal to the implant housing for delivery by bone conduction of the skull bone as an audio signal to the cochlea of the patient.
1. An implantable magnetic transducer arrangement for a hearing implant in a recipient patient, the arrangement comprising:
an implant housing hermetically encapsulating an interior housing volume and adapted to be fixedly attached to skull bone beneath the skin of the patient;
a magnetic transducer within the housing volume having:
i. a plurality of permanent magnets wherein adjacent magnets have opposite magnetic polarities;
wherein the magnets include: an inner cylindrical magnet, and at least one ring magnet positioned concentrically outside the inner cylindrical magnet; and
ii. one or more suspension elements configured for resilient coupling of adjacent magnets to allow movement between the adjacent magnets relative to each other;
wherein the suspension elements include a spring membrane positioned between the inner cylindrical magnet and the at least one ring magnet, the spring membrane directly coupled to the cylindrical magnet on one side and directly coupled to the at least one ring magnet on the opposite side;
wherein the magnetic transducer is operatively coupled to an external magnetic drive component located above the skin of the patient;
wherein the magnetic transducer and the external magnetic drive component are configured to cooperate together to form an oscillating system that develops a mechanical stimulation signal to the implant housing for delivery by bone conduction of the skull bone as an audio signal to the cochlea of the patient.
2. A transducer arrangement according to claim 1 , wherein at least one of the magnets interacts with an external holding magnet to affix the external drive coil in position on the skin of the patient.
3. A hearing implant system having an implantable magnetic transducer arrangement according to any of claim 1 , or 2 .