Piezoelectric power generator portable power supply unit equipped with the same, and portable electronic device equipped with the same

摘要

In a power generator including a piezoelectric transducer which generates electric power upon application of a strain, efficiency of converting strain energy into electric energy is improved to achieve a small-sized piezoelectric power generator having a charging capability adaptable for practical use and to provide a portable electronic device equipped with the piezoelectric power generator. The power generator includes a vibrating arm (21) having a sandwich structure wherein a support layer (26) is held between piezoelectric portions (22a) and (22b) on both sides, the vibrating arm being wider in the side of a support end (24) than in the side of a free end (23). Since the piezoelectric portions (22a) and (22b) are extended to a root portion of the vibrating arm (21), strain energy can efficiently be converted into electric energy. Since the piezoelectric portions (22a) and (22b) each have a laminated structure, a piezoelectric power generator having the electromotive voltage and the capacitance optimum for charging can be realized. In one embodiment two vibrating arms are provided, having their ends coupled together, so that they are in the form of a tuning fork.