Patent ID: 9420377
Filing Date: 2016-08-16
CPC Classification: H04R

Claim Text:
1. An audio playback device comprising: a magnetic module comprising a magnetic source and two yokes, wherein each of the two yokes is connected to one of two magnetic poles generated by the magnetic source, and the two yokes extend substantially in parallel to form a magnetic field therebetween; an annular armature comprising a first arm, a second arm, a third arm and a fourth arm that form a hollow area, wherein the third arm and the fourth arm are respectively connected the first arm and the second arm, and at least part of the first arm is located in the magnetic field; at least one coil module, wound on the second arm and generating two varying electro-magnetic poles corresponding to the third arm and the fourth arm respectively according to an alternating current signal in the annular armature, such that the annular armature vibrates according to a magnetic relation of the two varying electro-magnetic poles and the magnetic field; and a diaphragm connected to the annular armature through a driving rod to vibrate according to a vibration of the annular armature so as to generate a sound wave.