| 摘要 |
PURPOSE:To improve the rust-resistance and ridigity of a diaphragm and the reproducing characteristics in a high pitch region, by forming a film by a chemical conversion treatment and a synthetic resin film on said film on the diaphragm using Mg or Mg alloy as the base. CONSTITUTION:Mg-Al-Zn alloy, 44mum thick is pressed to form a dome shaped diaphragm 1. After rinsing the surface, the diaphragm is impregnated in a chromate processing liquid at 20-40 deg.C to form a chemical conversion film 2 and water rinsing and drying are processed immediately. A solution contg. 0.05wt% of mercaptan as polymerization catalyzer in methyl methacrylate and the diaphragm 1 are arranged in a vacuum-deposition device to form a film 3 of polymethyl methacrylate, about 1.5mum thick on the film 2 of chromate. Further, the diaphragm is taken out from the vacuum-deposition device for heat treatment and the methyl methacrylate is completely polymerized, then the desired diaphragm for speaker can be obtained. |
