| 摘要 |
PROBLEM TO BE SOLVED: To provide a bone conduction speaker which is small in size and light in weight, saves power, by which air conduction sound other than a bone conduction sound can also be heard well, and which is excellent in mounting property. SOLUTION: The bone conduction speaker is mounted with a laminated piezoelectric actuator (laminated piezoelectric element) 1 as a piezoelectric element for generating acoustic vibration in a through hole 5 of a rubber tube 4 being a cylindrical container composed of an elastic body through a basket-like transition magnification mechanism (an outer shell bar member 2 is shown) for magnifying the transition of its longitudinal direction. In order to also hear the air conduction sound other than the bone conduction sound in the mounting state, the speaker has a structure of forming a gap between the actuator 1 and the through hole 5. Moreover, as a driving signal for driving the actuator 1 for generating the acoustic vibration, a signal generated by applying a fixed DC bias voltage to a voice signal obtained from a voice signal source 8 by an amplifier circuit 7 is used. COPYRIGHT: (C)2006,JPO&NCIPI
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