Method for manufacturing an acoustic sensor, and acoustic sensor obtained thereby, having a substantially non-detachable protective layer

A method of manufacturing a shockwave acoustic sensor for sensing shockwaves comprising the steps of:

• providing an elongated support member having a front end positionable in a direction facing the shockwaves to be sensed, a rear end opposite said front end and at least one lateral surface joining said front and rear ends;
• providing a piezoelectric sheet having a first surface provided with a first metal strip defining a first electrode having first and second portions, and a second opposite surface provided with a second metal strip having first and second portions defining a second electrode, said first portions of said first and second electrodes overlapping for defining an active sensing area;
• mounting said piezoelectric sheet on said support member with said overlapping first positions of said first and second electrodes on said front end of said support member and with the second portions of said first and second electrodes on said at least one lateral surface of said support member;
• connecting said second portions of said first and second electrodes with respective electrical conductors;
• and
• coating said piezoelectric sheet with a macroscopically undeformable protective coating layer on said front end of said support member and at least a part of said at least one lateral surface of said support member comprising said second portions of said electrodes, said protective coating layer being made of a single polymerizable material having a thickness effective for sealing the piezoelectric sheet in a macroscopically undeformable block of material when receiving shockwaves.