| 摘要 |
A capacitive force transducer, particularly suited for use as a microphone or as a phonograph needle pick-up cartridge, comprises a diaphragm electrode insulatively held to a lip portion of a recess in a second electrode, thereby forming a capacitive detector. The lip structure of the second electrode structure has a capacitive face region diverging from a virtual pivot region at the lip where the diaphragm is pivotably affixed to the recessed electrode. In this manner, the quiescent capacitance is defined predominantly by the capacitance near the lip, which is relatively small and defined and the change in capacitance for a given deflection of the diaphragm is relatively large, thereby improving the sensitivity of the transducer. In the case of a phonographic pick-up cartridge, the pick-up needle is coupled to the diaphragm so that vibrations induced in the needle produce corresponding vibrations of the diaphragm. A batch method of fabricating the transducers comprises recessing a semiconductive wafer through a major face to define a plurality of capacitive regions around the margins of the recesses. The diaphragm is conveniently formed by a layer deposited over an insulative layer deposited on the non recessed face of the wafer. The wafer is diced to provide a batch of the transducers.
|
