Patent 7377175 was granted and assigned to Sanyo on May, 2008 by the United States Patent and Trademark Office.
A sensor hard to break and capable of improving sensitivity is obtained. This sensor comprises an electrode plate and a diaphragm, opposed to the electrode plate, including a first elastic film arranged on a central portion and a second elastic film, arranged at least on a peripheral portion of the first elastic film, made of a material having a lower elastic modulus than the first elastic film.