Yamaha Corporation

Hiroaki Itoh

Toshiharu Hoshi

Kenzaburou Iijima

Osamu Mochizuki

A speaker diaphragm has a laminated construction in which a core layer is made of a porous diamond type wafer or wafers and sandwiched by a pair of surface layers made of diamond type material. Presence of numerous small pores in the core layer reduces the specific gravity of the entire diaphragm, thereby increasing efficiency in acoustic conversion. The porous construction of the core layer reduces internal loss of the diaphragm, and suppresses resonance in the treble range.

Speaker diaphragm

A chemical vapor deposition apparatus deposits a thin film on a substrate according to a chemical vapor deposition method by using plasma energy and reaction gas. The chemical vapor deposition apparatus comprises at least a reaction tube, a waveguide and a substrate holder. The reaction tube is inserted through the waveguide to thereby form a reaction vessel. The reaction tube is connected with a reaction gas source, and reaction gas is introduced into the reaction tube. The substrate holder is placed at an area in which the reaction tube and the waveguide intersect. The substrate holder provides a rotation axis for rotating the substrate, and the waveguide is provided such that a center axis thereof is inclined in relation to a center axis of the substrate holder. In addition, the substrate holder can be freely rotated around the center axis thereof. By rotating the substrate so that a plasma is generated at the position opposite to and inclined against the substrate, all portions of the substrate are heated uniformly. Thus, a thin film having uniform thickness can be deposited over the entire surface of the substrate.

Growing community of inventors

Shizuoka, Japan

Hiroaki Itoh