The invention relates to a
piezoelectric sensor for the improved measurement of mechanical variables such as force, pressure or measurement variables which are derived there from, particularly a PVDF film sensor having an improved sensitivity and temperature stability of the measurement
signal for pressure measurements that vary in time and / or space, and for the one- and two-dimensional determination of the position and propagation velocity of pressure fluctuations and pressure
waves with a
single measurement sensor at a measurement location. A preferred field of application of the invention is the non-invasive, low strain and
continuous measurement of the
pulse rate and the systolic and diastolic
blood pressure of humans and animals by determining the velocity and the
signal form of the pulse
waves. The object of the invention is to allow the measurements of the
blood pressure and the
pulse rate, for example even in the case of emergency patients having only a very low
blood pressure and patients having circulatory disorders in the extremities, for example patients which have developed diabetes or the “smoker's leg”, by using only one sensor at a measurement location due to the improved measurement sensitivity of the
piezoelectric sensor, with the result that the continuous application of a pressurized jacket for continuously measuring and monitoring the blood pressure is not necessary. The present invention solves this problem in that a plurality of parallel strips of a piezoelectric material (1) are associated as a measurement membrane in the
pressure sensor according to the invention with a sensor base body (4) in such a manner that the parallel strips are tension preloaded in a one-dimensional and elastic manner in the direction of the piezo
dipole orientation and that an empty cavity (5) is provided between the tension preloaded
piezoelectric sensor material (1) in the measurement portion and the sensor base body (4), formed by a recess / cutout.