| 摘要 |
PURPOSE:To make a vibration within an ear difficult to be transmitted to a unit by positioning, symmetrically to the center axis of the unit, an adjustable aperture for specific character of a unit case and the through holes of an insertion instrument for holding within an earhole or a concha. CONSTITUTION:Through holes 8' are provided on an insertion instrument 8 for holding within the concha and a mutual position between the through holes 8' and the backward aperture of a unit case 2 is constituted so as to make a distance larger between an aperture 7 and the through holes 8' by positioning the through holes symmetrically to a unit 1, in other words, the axis of the case 2. Thereby, keeping an enough space between the through holes 8' and the aperture 7, the transmission of a filled tone peculiar to a bone conduction that is caused by the transmission of a speaker's voice, in use of a microphone, which is transferred to an earhole through the bone conduction and is transferred from through holes 8' to the unit 1 through the aperture 7 of the case 2 is screened or dampted, or a vibration within an ear is difficult to be transmitted to the unit 1. |
