Implantable medical device and method to manufacture such a device
An implantable medical device includes a first substrate based on a biocompatible material, wherein the first substrate constitutes a part of a housing of the device and has an external side configured to be put in contact with the biological tissues of a user, wherein the device comprises at least one ultrasonic transducer within a cavity created on an internal side of the first substrate, wherein the transducer is configured so that no layer of air, of gas or of void separates the transducer from the first substrate.
1 . An implantable medical device comprising:
a first substrate based on a biocompatible material, wherein the first substrate constitutes a part of an encapsulation housing of the device and has an external side, defining an external side of the encapsulation housing, configured to be put in contact with the biological tissues of a user, and an internal side opposite to the external side; and
at least one ultrasonic transducer within a non-through cavity formed in the first substrate on the internal side of the first substrate,
wherein the ultrasonic transducer comprises a layer of a piezoelectric material distinct from the first substrate, the ultrasonic transducer being configured so that no layer of air, of gas or of void separates from the internal side of the first substrate.
2 . The device according to claim 1 , wherein the first substrate is based on an electrically isolating material, for example on sapphire.
3 . The device according to claim 1 , additionally comprising, over the internal side of the first substrate, interconnecting metal elements respectively connected to first and second electrodes of the transducer.
4 . The device according to claim 3 , additionally comprising, over the internal side of the first substrate, a control electronic circuit connected to the first and second electrodes of the transducer via said interconnecting metal elements.
5 . The device according to claim 1 , wherein the piezoelectric layer of the transducer is based on a piezoelectric ceramic, for example on PZT.
6 . The device according to claim 1 , wherein the housing additionally comprises an upper cover based on the same material as the first substrate, for example soldered to the first substrate, that hermetically encapsulates the ultrasonic transducer.
7 . A method to manufacture the device according to claim 1 , comprising a step of manufacturing said cavity, following by a step of transfer and fixation of the transducer into the cavity.
8 . The method according to claim 7 , wherein the cavity is manufactured by laser ablation.
9 . The device according to claim 1 , wherein the ultrasonic transducer comprises a lower metallic electrode disposed on and in contact with the internal side of the first substrate.