Patent ID: 8391520

Claim:
A flat speaker unit, comprising: a first vibrating membrane, having a first surface and a second surface, the first surface disposed with a first conductive electrode for blocking moisture; a second vibrating membrane, having a first surface and a second surface, the first surface disposed with a second conductive electrode for blocking moisture; an electrode structure, disposed between the second surface of the first vibrating membrane and the second surface of the second vibrating membrane; a first supporting member layer, disposed between the first vibrating membrane and the electrode structure; and a second supporting member layer, disposed between the second vibrating membrane and the electrode structure, wherein the first vibrating membrane, the first supporting member layer, the electrode structure, the second supporting member layer, and the second vibrating membrane stack into a stacked structure, and the first conductive electrode and the second conductive electrode are placed on opposite outer-sides of the stacked structure to form a resonance chamber within the stacked structure.