| 摘要 |
<p>A hollow inner section is formed when a pair of frames (16, 17) are combined, and a plate (38) which concentrates a magnetic flux is arranged on permanent magnets (32, 33) arranged inside the pair of frames (16, 17). In a diaphragm (21), a coil pattern (21b) which receives the magnetic flux from the plate (38) is formed on the vibrating film (21a), and the vibrating film (21a) having uniform thickness is formed as an uneven solid structure.</p> |
