DIAPHRAGM FOR SPEAKER AND ITS MANUFACTURE

摘要

PURPOSE:To prevent production of crack or chipping and to enhance a high frequency sound characteristic by forming a diamond on a semi-spherical part and an amorphous diamond on an outer circumferential flange so as to decrease an internal residual stress of the flange. CONSTITUTION:A silicon base 4 is fixed on a cooling support base 2 in a vacuum chamber 1. A raw material gas is introduced from an intake 8 of the chamber 1, the gas is heated by a filament 5, a gas-phase reaction is caused and a diamond film is formed on the base 4. Then a laser beam is emitted only to the outer circumferential flange to apply groove processing thereby forming an amorphous diamond onto the outer circumferential flange. The outer circumferential flange contains a graphite and an amorphous carbon. As a result, the stiffness of the part processed by the amorphous diamond is enhanced, the internal residual stress is decreased and the diaphragm having a sufficient stiffness is obtained in which a crack or chipping is hardly produced.