Patent ID: 6543573
Filing Date: 2003-04-08
Classification: H04R

Abstract:
A speaker unit, comprising:a diaphragm and a mechanism for driving the diaphragm, said diaphragm formed into a foam sheet or plate of aromatic polycarbonate resin having a 0.5 to 10 mm thickness, a density of 0.03 to 0.6 g/cm3, an elastic modulus in tension of said foam sheet or plate of at least 1 MPa at temperatures of 25Â° C., 50Â° C., 80Â° C. and 105Â° C., and a tan &dgr; of said foam sheet or plate at least 0.02 at a temperature ranging from 25 to 105Â° C. during measurement of the dynamic viscoelasticity in bending tests giving 1 Hz frequency oscillation strain.