DIAPHRAGM FOR SPEAKER AND ITS PRODUCTION

摘要

PURPOSE:To obtain a light-weight and high-rigidity speaker diaphragm by forming aluminum oxide having a large specific modulus into a sheet of several 10mum thickness to press mold. CONSTITUTION:First, a 5% aluminum oxide sol is mixed with an aqueous solution of 5% polyvinyl alcohol 1:3 ratio to cast on a glass plate and to obtain a sheet of 140mum thickness. This sheet is exposed into steam for 2-3sec and then undergoes a press molding by menas of an upper and a laver die which are heated up to about 70 deg.C. Then this molded dome is baked 2hr at about 1,500 deg.C to obtain a dome diaphragm made of aluminum oxide with 70mum thickness. Such aluminum oxide is porous to attain 1.5g/cm<3> density and 6X10<11>cm<3>/sec<2> Young's modulus.