Patent ID: 8625824

Claim:
A flat speaker unit, comprising a first porous electrode, a second porous electrode, a vibrating membrane with an electret layer and an electrode layer disposed therebetween, wherein the first porous electrode comprises a first porous metal thin film and a first porous layer, the second porous electrode comprises a second porous metal thin film and a second porous layer, and an air gap is respectively formed between the first porous electrode and the vibrating membrane and between the second porous electrode and the vibrating membrane, so as to produce sounds through forces between the first porous electrode, the second porous electrode and the vibrating membrane, wherein the electrode layer is formed on the electret layer, a plurality of first supporting members are disposed between and contacted to the first porous electrode and the vibrating membrane, a plurality of second supporting members are disposed between and contacted to the second porous electrode and the vibrating membrane, and the first porous electrode, the second porous electrode and the vibrating membrane are combined, supported and spaced from each other by a frame supporter, wherein the flat speaker unit is fixed by the frame supporter.