ALEXANDRIA, Va., Sept. 3 -- United States Patent no. 12,407,987, issued on Sept. 2, was assigned to AAC Microtech (Changzhou) Co. Ltd. (Changzhou, China).
"Speaker device" was invented by Zhang Ren (Changzhou, China) and Zhiwei Zhong (Changzhou, China).
According to the abstract* released by the U.S. Patent & Trademark Office: "Provided is a speaker device, including a first frame, a first vibration system, a magnetic circuit system, a second frame, a second vibration system, a second voice coil, and a conductive member electrically connected to the second voice coil. The magnetic circuit system includes a lower splint, a first main magnetic steel, a first sub-magnetic steel, a pole core, a second main magnetic steel, and a second sub-mag...