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US 4,841,775 AGranted
Vibratory transducer
AssigneeYokogawa Electric Corporation
InventorsKyoichi Ikeda, Tetsuya Watanabe, Yasushi Higashino
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AssigneeYokogawa Electric Corporation
InventorsKyoichi Ikeda, Tetsuya Watanabe, Yasushi Higashino
Estimating the term…
A vibratory transducer comprising a vibratory beam composed of an n-type layer and having at least one end fixed. The vibratory beam is formed by selectively etching an n-type layer formed by adding impurities locally to a single silicon crystal. The vibratory transducer also comprises means for vibrating the vibratory beam and means for detecting vibration of the vibratory beam. The vibratory transducer measures pressure, temperature, density, etc, by detecting change in the resonant frequency of the vibratory beam. The vibratory beam can be finely etched irrespective of the density of the impurities therein by forming the vibratory beam in an alkaline aqueous solution while applying a negative DC or pulsed voltage to a p-type layer and a positive DC or pulsed voltage to an n-type layer. The vibrating and detecting means for the vibratory beam can be easily provided by making a diode and a transistor including the vibratory beam in the transducer.
A vibratory transducer for vibrating a vibratory beam formed on a single silicon crystal at a natural frequency thereof and for detecting a change in the frequency of vibration of the vibratory beam dependent on change in a force applied on said single silicon crystal or environment, said transducer comprising a single silicon crystal which comprises a p-type semiconductor conductor containing impurities at a concentration of 10.sup.. or 10.sup.17 atoms/cm.sup.3 or less, and an n.sup.+ diffused layer of a single silicon crystal containing impurities at a concentration ranging from 10.sup.17 to 10.sup.18 atoms/cm.sup.3 ;
Dependencies are inferred from the claim text.