| 摘要 |
PURPOSE:To improve a frequency characteristic, by placing the center part and the end part of a diaphragm which is obtained by printing a voice coil conductor on a heat resisting insulation foil, between a pole piece, and a plate for forming a magnetic pole, which have been divided into two parts, respectively. CONSTITUTION:On an E-shape pole piece 12 are provided a substrate part 12a, a center part 12b and also a split piece 12c to be connected to the upper surface of the center part 12b. A plate 10 is divided into two parts and its split pieces 10a, 10b are connected to the upper surface of magnets 11, 11 provided on both sides of the pole piece 12. Also, the center part of a diaphragm 13 which has been manufactured by printing a voice coil 14 on a heat resisting insulation foil of polyamide, etc. by means of photoetching is held between the pole pieces 12b, 12c, and its both side parts are held between the split plates 10a, 10b. In this way, since the diaphragm is operated in the center part of the magnetic circuit, improvement for high efficiency and low distortion rate is realized easily. |
