| 摘要 |
PURPOSE:To obtain remarkably efficient anti-magnetic device of a speaker cheaply y providing a back chamber for making a back cavity behind a speaker and constituting the back chaber by a magnetic material. CONSTITUTION:A general speaker is composed of a bottom plate 1, a magnet 2... a dust cap 11 or the like. Similarly to the conventional speaker, a leakage of magnetic flux (b) is generated from a magnetic circuit 4. But by providing the back chamber 16 composed of magnetic material, the magnetic flux (b) flows through the back chamber 16. Therefore the outside magmetic flux of the back chamber becomes extremely small. In this manner, by constituting the back chamber 16 for forming a back cavity with magnetic material, even in the conventional speaker, the leakage of the magnetic flux can be decreased and the anti-magnetic device eliminating te influence to the screen of a television can be realized inexpensively. |
