| 摘要 |
PURPOSE:To increase the rigidity of a diaphragm, to enlarge a piston area and to improve sound pressure levels by providing a flat part formed by the 1st groove disposed in the circumferential direction and the 2nd groove disposed in the diameter direction. CONSTITUTION:A generation line 14 in the diameter direction of approximately inverse truncated cone paper is set to a trough line. V-shaped grooves 15a and 15b which open upward to a voice coil joint part and plural V-shaped grooves 16a extending to an arbitrary circle at the inner diameter side are provided in the circumferential direction. Furthermore, coaxial shallow V-shaped grooves 17a-17d which intersect the V-shaped grooves in the diameter direction three- dimensionally are formed, while flat parts 18a-18d are formed between both V- shaped grooves. Thus the rigidity is increased with respect to a vertical curvature of a flat diaphragm, and its weight can be reduced substantially, compared with conventional one. |
