To solve the problems, wherein a piezoelectric composition pressure sensitive element constituting a piezoelectric element absorbs water, electrical resistance, capacitance, and piezoelectric characteristics changes, and the durability and reliability deteriorate, when a conventional piezoelectric element is used under a high-temperature and high-humidity environment.
The piezoelectric element comprises the piezoelectric composition pressure sensitive element 1, containing a first coating layer 6 by a water-repellent material, piezoelectric ceramic powder 3 where a second coating layer 7 by a coupling agent is formed, and an organic polymer 4; a first electrode 2A, connected to the piezoelectric composition pressure-sensitive element 1; and a second electrode 2B that is connected to the piezoelectric composition pressure-sensitive element 1 and is insulated from the first electrode 2A. Thus, since the penetration of water to the piezoelectric composition pressure-sensitive element 1 is suppressed, even under high temperature and high humidity, the softening of the piezoelectric composition pressure-sensitive element 2 is prevented, and elution of the constituent of the piezoelectric ceramic powder 3 can be prevented, thus preventing electrical characteristics, such as electrical resistance and capacitance from changing, preventing mechanical strength from decreasing and realizing improved durability and reliability.
HASHIDA TAKU
FUJII YUKO
OGINO HIROYUKI
Hiroki Naito
Daisuke Nagano
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