| 摘要 |
PURPOSE:To improve the rigidity of a diaphragm and to increase the reproduction band by bonding the surface material to the surface of a flat plate type core material made of a plastic foam along the projecting/recessing parts formed on the surface of said core material. CONSTITUTION:A core material 1 is made of a styrene foam, and surface materials 2 and 2' use the aluminum foils containing the recessed parts 3 and 3' having the 2mm. diameter and 0.3mm. thickness with about a 3mm. interval. In addition, a polyamide film adhesive is used between the material 1 and materials 2 and 2'. Then these materials 2 and 2' are adhered to the surface of the material 1 by means of metal molds 4 and 4'. In other words, the parts 3 and 3' of the materials 2 and 2' are pushed into the material 1, and at the same time the entire surfaces of the materials 2 and 2' are adhered along the surface of the material 1. |
