| 摘要 |
PROBLEM TO BE SOLVED: To provide a small speaker where a directional characteristics in a high area is improved by installing a cap arranged on the upper side of a voice coil bobbin wound to a voice coil constituting a vibration system, forming the cap in a spherical form and forming a diffuser. SOLUTION: The length of a voice coil bobbin 8 is selected so that it protrudes to a side upper than an inner diameter part formed in the center of a corn 7. A diffuser sharing cap, which has an elliptic diameter or a spherical diameter similar to or larger than that of the voice coil bobbin 8 is jointed to the upper opening art of the voice coil bobbin 8 through adhesive. The diffuser sharing cap 15 can easily be constituted in a spherical or elliptic form by forming synthetic resin by a pressure back forming method and an air blow forming method. Thus, the directional characteristics of a high area is improved, the high area is diffused by the diffuser sharing cap and sound band can considerably be widened.
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