ALEXANDRIA, Va., Sept. 10 -- United States Patent no. 12,413,912, issued on Sept. 9, was assigned to AAC Microtech (Changzhou) Co. Ltd. (Changzhou, China).
"Sound device" was invented by Li Ren (Changzhou, China) and Chao Zhang (Changzhou, China).
According to the abstract* released by the U.S. Patent & Trademark Office: "The present disclosure discloses a sound device including a frame, a magnet system, and a first vibration system and a second vibration system. The magnet system includes a first inner yoke, a main magnet fixed to the first inner yoke, and a second inner yoke fixed to one side of the main magnet away from the first inner yoke; the first vibration system includes a first diaphragm, a first coil surrounding the second inne...