ALEXANDRIA, Va., Oct. 28 -- United States Patent no. 12,452,605, issued on Oct. 21, was assigned to ALPS ALPINE Co. LTD. (Tokyo).
"Speaker" was invented by Hiroki Toita (Fukushima, Japan) and Yusuke Yoshida (Fukushima, Japan).
According to the abstract* released by the U.S. Patent & Trademark Office: "A speaker includes a diaphragm having a perfectly circular hole in which a bobbin is attached and an oval or elliptical outer peripheral end. The diaphragm includes a perfectly circular cross-sectional area in the range of a predetermined height above a base having the perfectly circular hole. The diaphragm further includes an intermediate area whose outer surface has a small curvature radius above the perfectly circular cross-sectional area...