US Patent 7639829 Low-radiation electromagnetic earpiece

In an electromagnetic earpiece with a housing in which a coil through which an energizing current flows as well as a membrane are arranged such that the membrane can be excited to vibrate as a result of the energizing current, the parasitic leakage field generated by the electromagnetic earpiece is be reduced. This is accomplished by internally-running connection lines optimally close together between the ends of the coil and the electrical connections of the electromagnetic earpiece so that the leakage field thereby generated is kept optimally low according to the physical principle of a double conductor, producing an advantageous electromagnetic earpiece in a hearing aid device.