| 摘要 |
<p>The artificial hearing aid is installed in the ear passage of the deaf person and connected to an amplifier. The ferrule portion is sealed by adding to the impression obtained by moulding from the ear an annular thickened portion (53, 54) offet in relation to the straight section of the ferrule, which has drillings calibrated in frequencies. There can be two or more of the latter, conducting sounds and selecting frequencies, one of them being central and intersecting an inclined one, both opening near the tympanum. The ferrule can be mounted on an external portion shaped to fit inside the external ear.</p> |
