Electromagnetic bone conduction hearing device
An external component for a bone conduction hearing implant is described. An external housing is fixedly attached on the skin of a hearing implant patient over an implanted bone conduction hearing transducer. An electromagnetic drive coil arrangement is fixed within the external housing for conducting electrical current to develop electromagnetic drive signals. An attachment magnet arrangement is suspended within the external housing by a flexible spring arrangement and magnetically coupled to the drive coil arrangement and to a corresponding implant magnet arrangement within the implanted bone conduction transducer. The electromagnetic drive signals magnetically interact with the attachment magnet arrangement which reacts by vibrating on the spring arrangement and magnetically interacting with the implant magnet arrangement to generate a bone conduction vibration signal by the implanted bone conduction hearing transducer for perception by the patient as sound.
1. A bone conduction hearing implant system comprising:
an implanted bone conduction hearing transducer with an implant magnet arrangement comprising an inner center magnet having a first magnetic field direction and an outer ring magnet surrounding the inner center magnet and having a second magnetic field direction opposite to the first magnetic field direction; and
an external component comprising:
i. an external housing for fixed attachment on the skin of a hearing implant patient over the implanted bone conduction hearing transducer;
ii. an electromagnetic drive coil arrangement fixed within the external housing for conducting electrical current to develop electromagnetic drive signals; and
iii. an attachment magnet arrangement suspended within the external housing and the electromagnetic drive coil arrangement by a flexible spring arrangement and magnetically coupled to the drive coil arrangement and to the implant magnet arrangement within the implanted bone conduction hearing transducer;
iv. wherein the electromagnetic drive signals magnetically interact with the attachment magnet arrangement to cause the attachment magnet arrangement to vibrate on the spring arrangement and magnetically interact with the inner center magnet without significantly interacting with the outer ring magnet of the implant magnet arrangement to generate a bone conduction vibration signal by the implanted bone conduction hearing transducer for perception by the patient as sound.
2. A bone conduction hearing implant system according to claim 1 , further comprising:
at least one sensing microphone for developing an audio input signal to the external component.
3. A bone conduction hearing implant system according to claim 1 , wherein the attachment magnet arrangement is a cylindrical magnet suspended within and surrounded by the drive coil arrangement.
4. A bone conduction hearing implant system according to claim 1 , wherein the attachment magnet arrangement is suspended within and below the drive coil arrangement.