| Popis: |
An improvement in a capacitance type electrostatic transducer for transmitting and/or receiving pressure energy, wherein the transducer includes a relatively inflexible backplate with at least one major surface thereof formed of electrically conductive material, a relatively flexible membrane including a layer of electrically conductive material stretched across and coextensive with the one major surface of the backplate, electrically insulating means for maintaining a capacitor forming spacing between the major surface and the stretched membrane and wherein the major surface has protrusions extending through the spacing for supporting the membrane. The improvement is providing the protrusions as a multitude of discrete pedestals distributed over the major surface and formed by etching away the major surface except in photographically selected areas defining the pedestals. Each of the pedestals has a top surface covered by an individual thin piece of electrically insulating material remaining after a prior photographic developing process. |
