Acoustic radiation membrane for e.g. music watch, has asymmetrical regions i.e. ellipses, to maximize oscillation frequency of membrane in specific frequency band, where regions are excavated in membrane with different uniform thicknesses

摘要

The membrane (1) has asymmetrical regions i.e. ellipses (2, 3), for maximizing oscillation frequency of the membrane in a frequency band ranging from 1 kilohertz to 4 kilohertz, where the membrane is made of titanium or amorphous metal or metallic glass. The regions are excavated in the membrane with uniform thicknesses different from one another and smaller than overall thickness of the membrane. The regions are formed by locally modifying physicochemical properties of the material of the membrane in a deterministic manner. An independent claim is also included for a music or repeater watch comprising a case.