Piezoelectric sensor

A piezoelectric sensor comprising a piezoelectric element and a support with said piezoelectric element secured thereto for obtaining a measurement signal from an object under measurement through said support, wherein:

• said support is entirely or partly made of a material having a coefficient of thermal expansion equal to or near the coefficient of thermal expansion of a piezoelectric body used for said piezoelectric element;
• said support includes a vessel accommodating said piezoelectric element and a lower membrane interposed between said vessel and said piezoelectric element, at least said lower membrane being made of a material having said coefficient of thermal expansion;
• said piezoelectric sensor further comprises an upper member provided on the surface of said piezoelectric sensor on the side thereof opposite said support, said upper member being made of a material having a coefficient of thermal expansion equal to or near the coefficient of thermal expansion used for said piezoelectric element and having electrodes connected to electrodes of said piezoelectric element, said piezoelectric element and said upper member being spaced apart and facing each other, outer leads being connected to electrodes of said upper member;
• and wherein
• said piezoelectric sensor further comprises a cover member covering the periphery of a lamination including said lower member, said piezoelectric element and said upper member such that a space is secured around the periphery of said piezoelectric element, said lamination covered by said cover member being sealed by a sealing material.