Surface-Laminated Piezoelectric-Film Sound Transducer..
Patent, Filed 18 Oct 93, Patented 30 Mar 99
OFFICE OF THE SECRETARY OF THE NAVY WASHINGTON DC
Pagination or Media Count:
A sound transducer, which may be a microphone or a speaker, is constructed using a metallic film sandwich of piezoelectric film as the active element. The sandwich is laminated to a flat inflexible substrate, such as a printed circuit board, over substantially its entire surface area, so that it operates as a transducer without flexing the piezoelectric film. Since the piezoelectric film is less sensitive in this more than when it flexes, either the area of the sandwich must he large, or, as a microphone, the transducer must be subject to powerful sound waves. Such powerful sound waves are most easily achieved by either putting the micro phone in physical contact with the sound source or placing the microphone in a container pressure-field with the sound source. This entire package is then provided with impedance matching to connect it to an external point where the resulting signal can be used, is provided with a ground shield, and is encased in waterproof layers.
- Metallurgy and Metallography
- Structural Engineering and Building Technology
- Electricity and Magnetism