ALEXANDRIA, Va., Feb. 17 -- United States Patent no. 12,556,867, issued on Feb. 17, was assigned to ALMUS Corp. (Chungcheongnam-do, South Korea).
"Speaker unit for earphone" was invented by Jong Won Lee (Incheon, South Korea), Yun Uk Ha (Incheon, South Korea), Jeong Kwon Park (Gyeonggi-do, South Korea), Soon Hyuk Hong (Gyeonggi-do, South Korea) and Ji Wook Choi (Gyeonggi-do, South Korea).
According to the abstract* released by the U.S. Patent & Trademark Office: "A speaker unit for an earphone includes a frame including an internal accommodation space; a low-frequency diaphragm; a low-frequency voice coil of a tubular structure connected to the low-frequency diaphragm; a center magnet disposed at the center of the low-frequency voice coil...