| 摘要 |
PURPOSE:To compensate necessary frequency characteristics faithfully without any excess by fitting an oscillation-electricity transducing element of an electret in an insertion body to be inserted into the external auditory miatus. CONSTITUTION:The electret transducing element 5 has a fixed and a movable electrode, and an FET as an impedance transducing element inserted into an insertion hole 1b. An output level is adjusted according to the length and shape of the movable electrode 5d, the distribution ratio depending the position of a damper 5b, etc., and the frequency characteristics are determined by the elastic modulus of the damper 5b, weight of the movable electrode 5d, etc. When a user talks while the insertion body 1 is inserted into the external auditory miatus of the user, a bone conduction voice signal from the external auditory miatus wall is conducted to the transducing element 5 and transduced into an electric signal, which is sent to a transmitter to be radiated from an antenna in the form of a radio wave. Since the transducing element 5 uses the electret, output frequency characteristics are compensated best and converted into low impedance by an FET. Further, external oscillation such as a sound of friction against cloth which is conducted externally through a pipe 11 is damped temporarily by the elasticity of the pipe 11 and the mass of an external body 7 and further absorbed by the oscillation system consisting of a lead wire 5i, the damper 4, the tube 10, the spring elasticity of the elastic member 6, and the mass of the insertion body 1. |
