PIEZOELECTRIC-TYPE ELECTROACOUSTIC CONVERSION DEVICE

摘要

[PROBLEM TO BE SOLVED] Even when a shock due to a fall or the like is received, a piezoelectric element can be made resistant to damage, and the flatness of a frequency sound pressure characteristic can be improved. [SOLUTION] An outer periphery portion of a lower surface of a circular support plate 2, made of resin, is fixed to an upper surface of a ring-shaped frame 1. A circular through hole 3 is provided in the center portion of the support plate 2. An outer periphery portion of a lower surface of a circular metal plate 4 is fixed to a portion of an upper surface of the support plate 2 positioned at the circumference of the through hole 3. A groove 6 is provided in a ring shape and positioned inward from an outer periphery portion of an upper surface of the metal plate 4. A shock absorbing member 7, made of elastic materials such as a carbon-based material and poly urethane, is provided in the groove 6 of the metal plate 4. A piezoelectric element 8 is provided on a portion of the upper surface of the metal plate 4 positioned inward from the shock absorbing member 7, and a portion of an upper surface of the shock absorbing member 7 positioned on an inner periphery portion of the shock absorbing member 7 and at a circumference of the portion of the upper surface of the metal plate 4. Then, as a result of the presence of the shock absorbing member 7, even when a shock due to a fall or the like is received, the piezoelectric element 8 can be made resistant to damage, and the flatness of a frequency sound pressure characteristic can be improved.