| 摘要 |
PURPOSE:To eliminate effectively distortion of emitted sound, by forming a part of the voice coil structure of the speaker with Al and by subjecting Al to the anodic oxidation processing in the mixture solution of an organic acid and a sulfuric acid to prevent deformation. CONSTITUTION:Bobbin 8 and ring 9 constituting a voice coil are formed with Al thin plates of thickness 50-70mum, and both sides of all of them are subjected to anodic oxidation. The solution for anodic oxidation is generated by mixing 250g/l maleic acid and 3-5g/l sulfuric acid, and the temperature of this solution is set to 20-40 deg.C, and Al thin plates are soaked in this solution, and DC 3A/dm<2> is flowed to perform anodic oxidation. Formed Al2O3 has a very high hardness, and approximately 600Hv is obtained as Vickers hardness, and this Al2O3 does not generate crack and is uniform. Therefore, deformation is prevented effectively, and reinforcing ring 9 can be omitted in a certain case. Further, since the bobbin and the ring are made nonconductive, generation of a molten metal current is avoided, and distortion is avoided also. By the speaker dependent upon this constitution, emitted sound without distortion and with a high fidelity can be obtained. |
