General Electric Company

Paul Austin Lindsay

Oliver H Lieder

Jack E Howard

Brian Bowlds

Brian Burket Bowlds

A method for non-contact measurement of a displacement between a surface and a capacitive sensor comprised of at least two superimposed conductive plates electrically insulated one from the other and a sensor circuit coupled to the plates including: positioning the capacitive sensor proximate to the surface such that the displacement is a distance of a gap between the surface and one of the plates; applying a high frequency signal to the plates; applying the high frequency signal and a sensor plate to control a voltage gain of an amplifier in the circuit, where the capacitance on the sensor is indicative of the displacement between the sensor and surface; differentiating an output of the amplifier and the high frequency signal, and determining a value of the displacement based on the difference between the output of the amplifier and the high frequency signal.

Capacitive sensor and method for non-contacting gap and dielectric medium measurement

A non-contact capacitive sensor including: a sensor plate configured to be displaced from a surface and to measure a capacitance of a gap between the surface and sensor plate; an active shield plate over the sensor plate and insulated from said sensor plate, wherein a high frequency input signal is applied to the active shield plate and sensor plate; an effective ground shield plate connected through a first resistor to a ground, over the active shield plate to sandwich the active shield plate between the ground shield plate and the sensor plate, and the ground shield plate is insulated from the active shield plate, and a second resistor connected between the ground shield plate and the active shield plate to provide a direct current (dc) path through the sensor.

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Gardnerville, NV, United States of America

Paul Austin Lindsay