Abstract

A sensor suitable for sensing the relative movement between at least part of the sensor and one or more target objects. The sensor includes at least one polarised or at least partially polarised dielectric material and at least one electrode. The interaction of the one or more target objects with the static electric field of the dielectric material produces a signal or voltage change in the electrode. The static field may be produced by a material having a permanent polarization, i.e. an electret, or it can be induced by an electrode. A control circuit may monitor the output signal and generate a charging current to achieve or restore a desired surface charge on the dielectric. The sensing dielectric and the electrode may be applied as coating layers to a body. A protecting surface layer may be applied to the sensor.

IPC Classes  ?

• G01P 3/481 - Devices characterised by the use of electric or magnetic means for measuring angular speed by measuring frequency of generated current or voltage of pulse signals
• G01D 5/24 - Mechanical means for transferring the output of a sensing memberMeans for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for convertingTransducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying capacitance
• G01P 3/483 - Devices characterised by the use of electric or magnetic means for measuring angular speed by measuring frequency of generated current or voltage of pulse signals delivered by variable capacitance detectors