| 摘要 |
PROBLEM TO BE SOLVED: To stably obtain frequency characteristics at a level ranging from 800 to 3 KHz with respect to the frequency characteristics due to the mounting structure of an electromagnetic actuator. SOLUTION: An electromagnetic actuator is improved, such that the actuator is provided with a coil for application of an electric current (10), a magnet (20) that forms a magnetic circuit with a magnetic gap (G) separating the magnet (20) and a magnetic york (21), a diaphragm (11) that vibrates by application of a high frequency electric current, and a vibration plate (22) that vibrates by application of a low-frequency electric current, wherein the coil (10) is arranged within the magnetic gap (G) and each part is housed within an enclosure (3). According to an embodiment of the invention, an enclosure is provided with a radial oriented magnet, a vibration plate with a double suspension structure, and a bottom plate made of a magnetic shielding member so as to avoid the leak of a magnetic flux and frequency characteristics can be further improved by the mounting structure of the electromagnetic actuator. Furthermore, an elastic packing (5, 7) is interposed not only between the enclosure of the electromagnetic actuator and the housing case of a portable electronic device, but also between the enclosure of the electromagnetic actuator and a mounting substrate. COPYRIGHT: (C)2009,JPO&INPIT
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