Implantable microphone device

Abstract

An implantable microphone device is provided. The device comprises a hermetically sealed housing ( 3 ) having an internal cavity ( 2 ). The internal cavity ( 2 ) has a microphone assembly arranged to receive sound waves originating from external the housing ( 3 ). The device further comprises a pressure sensor arrangement, arranged to detect and determine the differential pressure between the internal cavity ( 2 ) and the exterior of the housing ( 3 ). The determined differential pressure is used to determine a suitable transfer function to be applied to the output of the microphone assembly to produce a signal representative of the received sound waves.

What is claimed is: 
     
         1 . An implantable transducer assembly, comprising:
 a hermetically sealed housing having an internal cavity;   a transducer assembly located in the hermetically sealed housing, wherein   the implantable transducer assembly is configured to determine a suitable transfer function to be applied to a transducer signal of the implantable transducer so as to produce a signal that takes into account a pressure of an environment exterior of the housing.   
     
     
         2 . The implantable transducer assembly of  claim 1 , wherein the implantable transducer assembly is configured to determine the suitable transfer function to be applied to the transducer signal of the implantable transducer so as to produce a signal that takes into account a pressure difference between the internal cavity and the environment exterior of the housing. 
     
     
         3 . The implantable transducer assembly of  claim 1 , further comprising:
 a pressure sensor arrangement, arranged to obtain data based at least in part on a pressure external to the housing, wherein   the implantable transducer assembly is configured to determine the suitable transfer function based at least in part on the obtained data obtained by the pressure sensor arrangement.   
     
     
         4 . The implantable transducer assembly according to  claim 1 , wherein said pressure sensor arrangement comprises:
 an external pressure sensor configured to detect the pressure external said housing, wherein the implantable transducer assembly is configured to determine the suitable transfer function based at least in part on output from the external pressure sensor.   
     
     
         5 . The implantable transducer assembly according to  claim 3 , wherein:
 said pressure sensor arrangement comprises a differential pressure sensor configured to determine a pressure difference between the environment external to the housing and the internal cavity, wherein the implantable transducer assembly is configured to determine the suitable transfer function based at least in part on output from the differential pressure sensor.   
     
     
         6 . The implantable transducer assembly according to  claim 1 , wherein:
 the transducer assembly is a microphone assembly, and wherein the microphone assembly comprises a microphone transducer and a cavity dividing membrane having an aperture, and wherein said microphone transducer is configured to receive sound waves via said aperture.   
     
     
         7 . The implantable transducer assembly according to  claim 3 , wherein the pressure sensor apparatus includes a strain gauge configured to measure a change in resistance experienced by a material that stretches due to a change in pressure. 
     
     
         8 . The implantable hearing prosthesis of  claim 17 , wherein:
 the processor is configured such that the calibration executed by the processor entails determining a transfer function to be applied to a signal of the transducer to account for the change in pressure of the external environment that influences the internal pressure.   
     
     
         9 . The implantable hearing prosthesis of  claim 17 , wherein:
 the implantable hearing prosthesis includes a membrane forming a portion of the hermetically sealed enclosure, which membrane enables the influence of the internal pressure by the pressure of the external environment.   
     
     
         10 . A method, comprising:
 obtaining data relating to a pressure phenomenon that influences a transfer function of a transducer implanted in a recipient;   compensating for the pressure phenomenon's influence on the transfer function; and   evoking a hearing percept using an implanted hearing prosthesis that includes the implanted transducer, the hearing percept based at least in part on the compensated influence on the transfer function.   
     
     
         11 . The method of  claim 10 , wherein:
 the action of obtaining data relating to the pressure phenomenon is executed using a pressure sensor exposed to an ambient environment of the implanted hearing prosthesis.   
     
     
         12 . The method of  claim 10 , wherein:
 the action of compensating for the influence on the transfer function is executed by a processor using a look-up table.   
     
     
         13 . The method of  claim 10 , wherein:
 the action of obtaining data relating to a pressure phenomenon that influences a transfer function of a transducer implanted in a recipient is executed by obtaining an actual external pressure external to the implanted hearing prosthesis; and   the action of compensating for the influence on the transfer function is executed by relating the transfer function and the obtained actual external pressure.   
     
     
         14 . The method of  claim 10 , wherein:
 the action of compensating for the influence on the transfer function is executed by relating the transfer function and the obtained data relating to the pressure phenomenon.   
     
     
         15 . The method of  claim 10 , wherein:
 prior to the action of obtaining data, a change in a pressure of an ambient environment of the implanted hearing prosthesis has occurred relative to that which was the case at a temporal location precedent, which change in pressure changed the transfer function of the transducer; and   the action of compensating for the influence on the transfer function entails obtaining a new transfer function based on the obtained data.   
     
     
         16 . The method of  claim 10 , wherein:
 the action of obtaining data relating to a pressure phenomenon that influences a transfer function of a transducer implanted in a recipient is executed by obtaining an actual external pressure external to the implanted hearing prosthesis; and   the action of compensating for the influence on the transfer function is executed by relating the transfer function and the obtained actual external pressure using a lookup table.   
     
     
         17 . An implantable hearing prosthesis, comprising:
 a transducer in a hermetically sealed enclosure, wherein the hermetically sealed enclosure is configured such that an internal pressure of the hermetically sealed enclosure is influenced by a pressure of the external environment of the hermetically sealed enclosure; and   a processor configured to calibrate the implantable hearing prosthesis to account for a change in pressure of the external environment of the hermetically sealed enclosure that influences the internal pressure of the hermetically sealed enclosure, wherein   the implantable hearing prosthesis is configured to evoke a hearing percept based on the calibration accounting for the change in pressure.   
     
     
         18 . The implantable hearing prosthesis of  claim 17 , wherein:
 the implantable hearing prosthesis is configured such that a transfer function of the transducer is influenced by the pressure of the external environment of the hermetically sealed enclosure due to the influence of the pressure of the external environment on the internal environment; and   the processor configured to calibrate the transfer function of the transducer to account for a change in pressure of the external environment of the hermetically sealed enclosure that influences the transfer function; and   the implantable hearing prosthesis is configured to evoke a hearing percept based on the calibrated transfer function.   
     
     
         19 . The implantable hearing prosthesis of  claim 18 , wherein:
 the implantable hearing prosthesis includes a lookup table including data relating transfer functions to the external pressure; and   the processor uses the lookup table to account for the change in pressure of the external environment.   
     
     
         20 . The implantable hearing prosthesis of  claim 18 , further comprising:
 a pressure sensor arrangement, arranged to obtain data based at least in part on the pressure of the external environment, wherein   the implantable hearing prosthesis is configured to determine a suitable transfer function based at least in part on the obtained data obtained by the pressure sensor arrangement.