| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain high wide band frequency characteristics and high heat resistance by forming a diaphragm with the non-expansible thin metal film having thickness of a specified range. SOLUTION: Since a highly expansible metal is generally low in rigidity and there is the possibility of causing permanent deformation due to impulsive sound pressure or the like in the case of forming a very thin film, a non- expansible metal having sufficient rigidity even in the case of forming the thin film is used while evading the highly expansible metal. As the non- expansible metal, nickel, chromium, titanium and the like are exemplified. As the diaphragm of an electrostatic type microphone or the like, it is preferable to use the non-expansible thin metal film of 0.5 to 5μm thickness. A thin metal film layer is formed on the surface of a substrate by electrodeposition or the like, and the obtained thin metal film layer is separated from the substrate, thereby forming the non-expansible thin metal film. Thus, excellent wide band frequency characteristics can be obtained. Also the heat resistance is remarkably improved, so that the metal film meets a reflow type soldering.</p> |
